vk: testing a robin_map key hash failure

Executable on device with: ./build.sh -p android -q arm64-v8a release test_compiler && adb push out/cmake-android-release-aarch64/filament/test/test_compiler /data/local/tmp/ && adb shell chmod 777 /data/local/tmp/test_compiler && adb shell /data/local/tmp/test_compiler
2024-07-26 12:23:28 +08:00
245 changed files with 6157 additions and 10434 deletions
--- a/.github/actions/android-continuous/action.yml
+++ b/.github/actions/android-continuous/action.yml
@@ -1,17 +0,0 @@
-name: 'Android Continuous'
-inputs:
-  build-abi:
-    description: 'The target platform ABI'
-    required: true
-    default: 'armeabi-v7a'
-runs:
-  using: "composite"
-  steps:
-    - uses: actions/setup-java@v3
-      with:
-        distribution: 'temurin'
-        java-version: '17'
-    - name: Run build script
-      run: |
-        cd build/android && printf "y" | ./build.sh continuous ${{ inputs.build-abi }}
-      shell: bash
--- a/.github/workflows/android-continuous.yml
+++ b/.github/workflows/android-continuous.yml
@@ -8,35 +8,32 @@ on:
      - rc/**

 jobs:
-  build-android-armv7:
-    name: build-android-armv7
+  build-android:
+    name: build-android
    runs-on: macos-14

    steps:
      - uses: actions/checkout@v4.1.6
-      - name: Run Android Continuous
-        uses: ./.github/actions/android-continuous
+      - uses: actions/setup-java@v3
        with:
-          build-abi: armeabi-v7a
-
-  build-android-armv8a:
-    name: build-android-armv8a
-    runs-on: macos-14
-
-    steps:
-      - uses: actions/checkout@v4.1.6
-      - name: Run Android Continuous
-        uses: ./.github/actions/android-continuous
+          distribution: 'temurin'
+          java-version: '17'
+      - name: Run build script
+        run: |
+          cd build/android && printf "y" | ./build.sh continuous
+      - uses: actions/upload-artifact@v1.0.0
        with:
-          build-abi: arm64-v8a
-
-  build-android-x86_64:
-    name: build-android-x86_64
-    runs-on: macos-14
-
-    steps:
-      - uses: actions/checkout@v4.1.6
-      - name: Run Android Continuous
-        uses: ./.github/actions/android-continuous
+          name: filament-android
+          path: out/filament-android-release.aar
+      - uses: actions/upload-artifact@v1.0.0
        with:
-          build-abi: x86_64
+          name: filamat-android-full
+          path: out/filamat-android-release.aar
+      - uses: actions/upload-artifact@v1.0.0
+        with:
+          name: gltfio-android-release
+          path: out/gltfio-android-release.aar
+      - uses: actions/upload-artifact@v1.0.0
+        with:
+          name: filament-utils-android-release
+          path: out/filament-utils-android-release.aar
--- a/.github/workflows/presubmit.yml
+++ b/.github/workflows/presubmit.yml
@@ -49,10 +49,8 @@ jobs:
          distribution: 'temurin'
          java-version: '17'
      - name: Run build script
-        # Only build 1 64 bit target during presubmit to cut down build times during presubmit
-        # Continuous builds will build everything
        run: |
-          cd build/android && printf "y" | ./build.sh presubmit arm64-v8a
+          cd build/android && printf "y" | ./build.sh presubmit

  build-ios:
    name: build-iOS
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -120,7 +120,7 @@ jobs:
        env:
          TAG: ${{ steps.git_ref.outputs.tag }}
        run: |
-          cd build/android && printf "y" | ./build.sh release armeabi-v7a,arm64-v8a,x86,x86_64
+          cd build/android && printf "y" | ./build.sh release
          cd ../..
          mv out/filament-android-release.aar out/filament-${TAG}-android.aar
          mv out/filamat-android-release.aar out/filamat-${TAG}-android.aar
--- a/NEW_RELEASE_NOTES.md
+++ b/NEW_RELEASE_NOTES.md
@@ -7,5 +7,3 @@ for next branch cut* header.
 appropriate header in [RELEASE_NOTES.md](./RELEASE_NOTES.md).

 ## Release notes for next branch cut
-
- Add support for multi-layered render target with array textures.
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ repositories {
 }

 dependencies {
-    implementation 'com.google.android.filament:filament-android:1.54.2'
+    implementation 'com.google.android.filament:filament-android:1.53.2'
 }
 ```

@@ -51,9 +51,19 @@ Here are all the libraries available in the group `com.google.android.filament`:
 iOS projects can use CocoaPods to install the latest release:

 ```shell
-pod 'Filament', '~> 1.54.2'
+pod 'Filament', '~> 1.53.2'
 ```

+### Snapshots
+
+If you prefer to live on the edge, you can download a continuous build by following the following
+steps:
+
+1. Find the [commit](https://github.com/google/filament/commits/main) you're interested in.
+2. Click the green check mark under the commit message.
+3. Click on the _Details_ link for the platform you're interested in.
+4. On the top left click _Summary_, then in the _Artifacts_ section choose the desired artifact.
+
 ## Documentation

 - [Filament](https://google.github.io/filament/Filament.html), an in-depth explanation of
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -7,29 +7,6 @@ A new header is inserted each time a *tag* is created.
 Instead, if you are authoring a PR for the main branch, add your release note to
 [NEW_RELEASE_NOTES.md](./NEW_RELEASE_NOTES.md).

-## v1.54.3
-
-
-## v1.54.2
-
- Add a `name` API to Filament objects for debugging handle use-after-free assertions
-
-## v1.54.1
-
-
-## v1.54.0
-
- materials: add a new `stereoscopicType` material parameter. [⚠️ **New Material Version**]
- Fix a crash when compiling shaders on IMG devices
-
-## v1.53.5
-
- engine: Fix bug causing certain sampler parameters to not be applied correctly in GLES 2.0 and on
-  certain GLES 3.0 drivers.
-
-## v1.53.4
-
-
 ## v1.53.3

 - Add drag and drop support for IBL files for desktop gltf_viewer.
--- a/android/gradle.properties
+++ b/android/gradle.properties
@@ -1,5 +1,5 @@
 GROUP=com.google.android.filament
-VERSION_NAME=1.54.2
+VERSION_NAME=1.53.2

 POM_DESCRIPTION=Real-time physically based rendering engine for Android.

--- a/build/android/build.sh
+++ b/build/android/build.sh
@@ -60,7 +60,13 @@ if [[ ! -d "${ANDROID_HOME}/ndk/$FILAMENT_NDK_VERSION" ]]; then
    yes | ${ANDROID_HOME}/cmdline-tools/latest/bin/sdkmanager --licenses
    ${ANDROID_HOME}/cmdline-tools/latest/bin/sdkmanager "ndk;$FILAMENT_NDK_VERSION"
 fi
+
+# Only build 1 64 bit target during presubmit to cut down build times during presubmit
+# Continuous builds will build everything
 ANDROID_ABIS=
+if [[ "$TARGET" == "presubmit" ]]; then
+  ANDROID_ABIS="-q arm64-v8a"
+fi

 # Build the Android sample-gltf-viewer APK during release.
 BUILD_SAMPLES=
@@ -68,19 +74,5 @@ if [[ "$TARGET" == "release" ]]; then
    BUILD_SAMPLES="-k sample-gltf-viewer"
 fi

-function build_android() {
-    local ABI=$1
-
-    # Do the following in two steps so that we do not run out of space
-    if [[ -n "${BUILD_DEBUG}" ]]; then
-        FILAMENT_NDK_VERSION=${FILAMENT_NDK_VERSION} ./build.sh -p android -q ${ABI} -c ${BUILD_SAMPLES} ${GENERATE_ARCHIVES} ${BUILD_DEBUG}
-        rm -rf out/cmake-android-debug-*
-    fi
-    if [[ -n "${BUILD_RELEASE}" ]]; then
-        FILAMENT_NDK_VERSION=${FILAMENT_NDK_VERSION} ./build.sh -p android -q ${ABI} -c ${BUILD_SAMPLES} ${GENERATE_ARCHIVES} ${BUILD_RELEASE}
-        rm -rf out/cmake-android-release-*
-    fi
-}
-
 pushd `dirname $0`/../.. > /dev/null
-build_android $2
+FILAMENT_NDK_VERSION=${FILAMENT_NDK_VERSION} ./build.sh -p android $ANDROID_ABIS -c $BUILD_SAMPLES $GENERATE_ARCHIVES $BUILD_DEBUG $BUILD_RELEASE
--- a/docs/Materials.md.html
+++ b/docs/Materials.md.html
@@ -1308,12 +1308,7 @@ Description
      declare a variable called `eyeDirection` you can access it in the fragment shader using
      `variable_eyeDirection`. In the vertex shader, the interpolant name is simply a member of
      the `MaterialVertexInputs` structure (`material.eyeDirection` in your example). Each
-      interpolant is of type `float4` (`vec4`) in the shaders. By default the precision of the
-      interpolant is `highp` in *both* the vertex and fragment shaders.
-      An alternate syntax can be used to specify both the name and precision of the interpolant.
-      In this case the specified precision is used as-is in both fragment and vertex stages, in
-      particular if `default` is specified the default precision is used is the fragment shader
-      (`mediump`) and in the vertex shader (`highp`).
+      interpolant is of type `float4` (`vec4`) in the shaders.

 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ JSON
 material {
@@ -1325,11 +1320,7 @@ material {
        }
    ],
    variables : [
-         eyeDirection,
-         {
-            name : eyeColor,
-            precision : medium
-         }
+         eyeDirection
    ],
    vertexDomain : device,
    depthWrite : false,
--- a/filament/CMakeLists.txt
+++ b/filament/CMakeLists.txt
@@ -61,7 +61,6 @@ set(SRCS
        src/Engine.cpp
        src/Exposure.cpp
        src/Fence.cpp
-        src/FilamentBuilder.cpp
        src/FrameInfo.cpp
        src/FrameSkipper.cpp
        src/Froxelizer.cpp
@@ -76,6 +75,8 @@ set(SRCS
        src/MaterialInstance.cpp
        src/MaterialParser.cpp
        src/MorphTargetBuffer.cpp
+        src/PerViewUniforms.cpp
+        src/PerShadowMapUniforms.cpp
        src/PostProcessManager.cpp
        src/RenderPass.cpp
        src/RenderPrimitive.cpp
@@ -124,12 +125,6 @@ set(SRCS
        src/details/Texture.cpp
        src/details/VertexBuffer.cpp
        src/details/View.cpp
-        src/ds/ColorPassDescriptorSet.cpp
-        src/ds/DescriptorSet.cpp
-        src/ds/DescriptorSetLayout.cpp
-        src/ds/PostProcessDescriptorSet.cpp
-        src/ds/ShadowMapDescriptorSet.cpp
-        src/ds/SsrPassDescriptorSet.cpp
        src/fg/Blackboard.cpp
        src/fg/DependencyGraph.cpp
        src/fg/FrameGraph.cpp
@@ -157,16 +152,19 @@ set(PRIVATE_HDRS
        src/HwVertexBufferInfoFactory.h
        src/Intersections.h
        src/MaterialParser.h
+        src/PerViewUniforms.h
+        src/PerShadowMapUniforms.h
        src/PIDController.h
        src/PostProcessManager.h
+        src/RendererUtils.h
        src/RenderPass.h
        src/RenderPrimitive.h
-        src/RendererUtils.h
        src/ResourceAllocator.h
        src/ResourceList.h
        src/ShadowMap.h
        src/ShadowMapManager.h
        src/SharedHandle.h
+        src/TypedUniformBuffer.h
        src/UniformBuffer.h
        src/components/CameraManager.h
        src/components/LightManager.h
@@ -194,14 +192,6 @@ set(PRIVATE_HDRS
        src/details/Texture.h
        src/details/VertexBuffer.h
        src/details/View.h
-        src/downcast.h
-        src/ds/ColorPassDescriptorSet.h
-        src/ds/DescriptorSetLayout.h
-        src/ds/PostProcessDescriptorSet.h
-        src/ds/ShadowMapDescriptorSet.h
-        src/ds/SsrPassDescriptorSet.h
-        src/ds/TypedBuffer.h
-        src/ds/TypedUniformBuffer.h
        src/fg/Blackboard.h
        src/fg/FrameGraph.h
        src/fg/FrameGraphId.h
@@ -219,6 +209,7 @@ set(PRIVATE_HDRS
        src/materials/fsr/ffx_a.h
        src/materials/fsr/ffx_fsr1.h
        src/materials/fsr/ffx_fsr1_mobile.fs
+        src/downcast.h
 )

 set(MATERIAL_SRCS
--- a/filament/backend/CMakeLists.txt
+++ b/filament/backend/CMakeLists.txt
@@ -12,7 +12,6 @@ set(PUBLIC_HDRS
        include/backend/AcquiredImage.h
        include/backend/BufferDescriptor.h
        include/backend/CallbackHandler.h
-        include/backend/DescriptorSetOffsetArray.h
        include/backend/DriverApiForward.h
        include/backend/DriverEnums.h
        include/backend/Handle.h
@@ -70,13 +69,9 @@ set(PRIVATE_HDRS
 if (FILAMENT_SUPPORTS_OPENGL AND NOT FILAMENT_USE_EXTERNAL_GLES3)
    list(APPEND SRCS
            include/backend/platforms/OpenGLPlatform.h
-            src/opengl/BindingMap.h
            src/opengl/gl_headers.cpp
            src/opengl/gl_headers.h
            src/opengl/GLBufferObject.h
-            src/opengl/GLDescriptorSet.cpp
-            src/opengl/GLDescriptorSet.h
-            src/opengl/GLDescriptorSetLayout.h
            src/opengl/GLTexture.h
            src/opengl/GLUtils.cpp
            src/opengl/GLUtils.h
@@ -500,38 +495,21 @@ endif()

 # ==================================================================================================
 # Compute tests
-#
-#if (NOT IOS AND NOT WEBGL)
-#
-#add_executable(compute_test
-#        test/ComputeTest.cpp
-#        test/Arguments.cpp
-#        test/test_ComputeBasic.cpp
-#        )
-#
-#target_link_libraries(compute_test PRIVATE
-#        backend
-#        getopt
-#        gtest
-#        )
-#
-#set_target_properties(compute_test PROPERTIES FOLDER Tests)
-#
-#endif()

-# ==================================================================================================
-# Metal utils tests
+if (NOT IOS AND NOT WEBGL)

-if (APPLE AND NOT IOS)
+add_executable(compute_test
+        test/ComputeTest.cpp
+        test/Arguments.cpp
+        test/test_ComputeBasic.cpp
+        )

-add_executable(metal_utils_test test/MetalTest.mm)
-
-target_link_libraries(metal_utils_test PRIVATE
+target_link_libraries(compute_test PRIVATE
        backend
        getopt
        gtest
        )

-set_target_properties(metal_utils_test PROPERTIES FOLDER Tests)
+set_target_properties(compute_test PROPERTIES FOLDER Tests)

 endif()
--- a/filament/backend/include/backend/DescriptorSetOffsetArray.h
+++ b/filament/backend/include/backend/DescriptorSetOffsetArray.h
@@ -1,101 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef TNT_FILAMENT_BACKEND_COMMANDSTREAMVECTOR_H
-#define TNT_FILAMENT_BACKEND_COMMANDSTREAMVECTOR_H
-
-#include <backend/DriverApiForward.h>
-
-#include <initializer_list>
-#include <memory>
-
-#include <stddef.h>
-#include <stdint.h>
-
-
-namespace filament::backend {
-
-void* allocateFromCommandStream(DriverApi& driver, size_t size, size_t alignment) noexcept;
-
-class DescriptorSetOffsetArray {
-public:
-    using value_type = uint32_t;
-    using reference = value_type&;
-    using const_reference = value_type const&;
-    using size_type = uint32_t;
-    using difference_type = int32_t;
-    using pointer = value_type*;
-    using const_pointer = value_type const*;
-    using iterator = pointer;
-    using const_iterator = const_pointer;
-
-    DescriptorSetOffsetArray() noexcept = default;
-
-    ~DescriptorSetOffsetArray() noexcept = default;
-
-    DescriptorSetOffsetArray(size_type size, DriverApi& driver) noexcept {
-        mOffsets = (value_type *)allocateFromCommandStream(driver,
-                size * sizeof(value_type), alignof(value_type));
-        std::uninitialized_fill_n(mOffsets, size, 0);
-    }
-
-    DescriptorSetOffsetArray(std::initializer_list<uint32_t> list, DriverApi& driver) noexcept {
-        mOffsets = (value_type *)allocateFromCommandStream(driver,
-                list.size() * sizeof(value_type), alignof(value_type));
-        std::uninitialized_copy(list.begin(), list.end(), mOffsets);
-    }
-
-    DescriptorSetOffsetArray(DescriptorSetOffsetArray const&) = delete;
-    DescriptorSetOffsetArray& operator=(DescriptorSetOffsetArray const&) = delete;
-
-    DescriptorSetOffsetArray(DescriptorSetOffsetArray&& rhs) noexcept
-            : mOffsets(rhs.mOffsets) {
-        rhs.mOffsets = nullptr;
-    }
-
-    DescriptorSetOffsetArray& operator=(DescriptorSetOffsetArray&& rhs) noexcept {
-        if (this != &rhs) {
-            mOffsets = rhs.mOffsets;
-            rhs.mOffsets = nullptr;
-        }
-        return *this;
-    }
-
-    bool empty() const noexcept { return mOffsets == nullptr; }
-
-    value_type* data() noexcept { return mOffsets; }
-    const value_type* data() const noexcept { return mOffsets; }
-
-
-    reference operator[](size_type n) noexcept {
-        return *(data() + n);
-    }
-
-    const_reference operator[](size_type n) const noexcept {
-        return *(data() + n);
-    }
-
-    void clear() noexcept {
-        mOffsets = nullptr;
-    }
-
-private:
-    value_type *mOffsets = nullptr;
-};
-
-} // namespace filament::backend
-
-#endif //TNT_FILAMENT_BACKEND_COMMANDSTREAMVECTOR_H
--- a/filament/backend/include/backend/DriverEnums.h
+++ b/filament/backend/include/backend/DriverEnums.h
@@ -19,16 +19,13 @@
 #ifndef TNT_FILAMENT_BACKEND_DRIVERENUMS_H
 #define TNT_FILAMENT_BACKEND_DRIVERENUMS_H

+#include <utils/BitmaskEnum.h>
 #include <utils/unwindows.h> // Because we define ERROR in the FenceStatus enum.

 #include <backend/Platform.h>
 #include <backend/PresentCallable.h>

-#include <utils/BitmaskEnum.h>
-#include <utils/FixedCapacityVector.h>
 #include <utils/Invocable.h>
-#include <utils/compiler.h>
-#include <utils/debug.h>
 #include <utils/ostream.h>

 #include <math/vec4.h>
@@ -100,8 +97,6 @@ static constexpr size_t MAX_VERTEX_ATTRIBUTE_COUNT  = 16;   // This is guarantee
 static constexpr size_t MAX_SAMPLER_COUNT           = 62;   // Maximum needed at feature level 3.
 static constexpr size_t MAX_VERTEX_BUFFER_COUNT     = 16;   // Max number of bound buffer objects.
 static constexpr size_t MAX_SSBO_COUNT              = 4;    // This is guaranteed by OpenGL ES.
-static constexpr size_t MAX_DESCRIPTOR_SET_COUNT    = 4;    // This is guaranteed by Vulkan.
-static constexpr size_t MAX_DESCRIPTOR_COUNT        = 64;   // per set

 static constexpr size_t MAX_PUSH_CONSTANT_COUNT     = 32;   // Vulkan 1.1 spec allows for 128-byte
                                                            // of push constant (we assume 4-byte
@@ -196,61 +191,6 @@ static constexpr const char* shaderLanguageToString(ShaderLanguage shaderLanguag
    }
 }

-enum class ShaderStage : uint8_t {
-    VERTEX = 0,
-    FRAGMENT = 1,
-    COMPUTE = 2
-};
-
-static constexpr size_t PIPELINE_STAGE_COUNT = 2;
-enum class ShaderStageFlags : uint8_t {
-    NONE        =    0,
-    VERTEX      =    0x1,
-    FRAGMENT    =    0x2,
-    COMPUTE     =    0x4,
-    ALL_SHADER_STAGE_FLAGS = VERTEX | FRAGMENT | COMPUTE
-};
-
-static inline constexpr bool hasShaderType(ShaderStageFlags flags, ShaderStage type) noexcept {
-    switch (type) {
-        case ShaderStage::VERTEX:
-            return bool(uint8_t(flags) & uint8_t(ShaderStageFlags::VERTEX));
-        case ShaderStage::FRAGMENT:
-            return bool(uint8_t(flags) & uint8_t(ShaderStageFlags::FRAGMENT));
-        case ShaderStage::COMPUTE:
-            return bool(uint8_t(flags) & uint8_t(ShaderStageFlags::COMPUTE));
-    }
-}
-
-enum class DescriptorType : uint8_t {
-    UNIFORM_BUFFER,
-    SHADER_STORAGE_BUFFER,
-    SAMPLER,
-    INPUT_ATTACHMENT,
-};
-
-enum class DescriptorFlags : uint8_t {
-    NONE = 0x00,
-    DYNAMIC_OFFSET = 0x01
-};
-
-using descriptor_set_t = uint8_t;
-
-using descriptor_binding_t = uint8_t;
-
-struct DescriptorSetLayoutBinding {
-    DescriptorType type;
-    ShaderStageFlags stageFlags;
-    descriptor_binding_t binding;
-    DescriptorFlags flags;
-    uint16_t count;
-};
-
-struct DescriptorSetLayout {
-    utils::FixedCapacityVector<DescriptorSetLayoutBinding> bindings;
-};
-
-
 /**
 * Bitmask for selecting render buffers
 */
@@ -330,6 +270,15 @@ enum class FenceStatus : int8_t {
    TIMEOUT_EXPIRED = 1,        //!< wait()'s timeout expired. The Fence condition is not satisfied.
 };

+/**
+ * Status codes for sync objects
+ */
+enum class SyncStatus : int8_t {
+    ERROR = -1,          //!< An error occurred. The Sync is not signaled.
+    SIGNALED = 0,        //!< The Sync is signaled.
+    NOT_SIGNALED = 1,    //!< The Sync is not signaled yet
+};
+
 static constexpr uint64_t FENCE_WAIT_FOR_EVER = uint64_t(-1);

 /**
@@ -419,18 +368,6 @@ enum class SamplerType : uint8_t {
    SAMPLER_CUBEMAP_ARRAY,  //!< Cube map array texture (feature level 2)
 };

-inline const char* stringify(SamplerType samplerType) {
-    switch (samplerType) {
-        case SamplerType::SAMPLER_2D: return "SAMPLER_2D";
-        case SamplerType::SAMPLER_2D_ARRAY: return "SAMPLER_2D_ARRAY";
-        case SamplerType::SAMPLER_CUBEMAP: return "SAMPLER_CUBEMAP";
-        case SamplerType::SAMPLER_EXTERNAL: return "SAMPLER_EXTERNAL";
-        case SamplerType::SAMPLER_3D: return "SAMPLER_3D";
-        case SamplerType::SAMPLER_CUBEMAP_ARRAY: return "SAMPLER_CUBEMAP_ARRAY";
-    }
-    return "UNKNOWN";
-}
-
 //! Subpass type
 enum class SubpassType : uint8_t {
    SUBPASS_INPUT
@@ -759,23 +696,6 @@ enum class TextureUsage : uint16_t {
    DEFAULT             = UPLOADABLE | SAMPLEABLE   //!< Default texture usage
 };

-inline const char* stringify(TextureUsage usage) {
-    switch (usage) {
-        case TextureUsage::NONE: return "NONE";
-        case TextureUsage::COLOR_ATTACHMENT: return "COLOR_ATTACHMENT";
-        case TextureUsage::DEPTH_ATTACHMENT: return "DEPTH_ATTACHMENT";
-        case TextureUsage::STENCIL_ATTACHMENT: return "STENCIL_ATTACHMENT";
-        case TextureUsage::UPLOADABLE: return "UPLOADABLE";
-        case TextureUsage::SAMPLEABLE: return "SAMPLEABLE";
-        case TextureUsage::SUBPASS_INPUT: return "SUBPASS_INPUT";
-        case TextureUsage::BLIT_SRC: return "BLIT_SRC";
-        case TextureUsage::BLIT_DST: return "BLIT_DST";
-        case TextureUsage::PROTECTED: return "PROTECTED";
-        case TextureUsage::DEFAULT: return "DEFAULT";
-        default: return "UNKNOWN";
-    }
-}
-
 //! Texture swizzle
 enum class TextureSwizzle : uint8_t {
    SUBSTITUTE_ZERO,
@@ -967,9 +887,6 @@ struct SamplerParams { // NOLINT

    struct EqualTo {
        bool operator()(SamplerParams lhs, SamplerParams rhs) const noexcept {
-            assert_invariant(lhs.padding0 == 0);
-            assert_invariant(lhs.padding1 == 0);
-            assert_invariant(lhs.padding2 == 0);
            auto* pLhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&lhs));
            auto* pRhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&rhs));
            return *pLhs == *pRhs;
@@ -978,9 +895,6 @@ struct SamplerParams { // NOLINT

    struct LessThan {
        bool operator()(SamplerParams lhs, SamplerParams rhs) const noexcept {
-            assert_invariant(lhs.padding0 == 0);
-            assert_invariant(lhs.padding1 == 0);
-            assert_invariant(lhs.padding2 == 0);
            auto* pLhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&lhs));
            auto* pRhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&rhs));
            return *pLhs == *pRhs;
@@ -988,12 +902,6 @@ struct SamplerParams { // NOLINT
    };

 private:
-    friend inline bool operator == (SamplerParams lhs, SamplerParams rhs) noexcept {
-        return SamplerParams::EqualTo{}(lhs, rhs);
-    }
-    friend inline bool operator != (SamplerParams lhs, SamplerParams rhs) noexcept {
-        return  !SamplerParams::EqualTo{}(lhs, rhs);
-    }
    friend inline bool operator < (SamplerParams lhs, SamplerParams rhs) noexcept {
        return SamplerParams::LessThan{}(lhs, rhs);
    }
@@ -1150,7 +1058,7 @@ struct RasterState {
            bool inverseFrontFaces                      : 1;        // 31

            //! padding, must be 0
-            bool depthClamp                             : 1;        // 32
+            uint8_t padding                             : 1;        // 32
        };
        uint32_t u = 0;
    };
@@ -1161,6 +1069,32 @@ struct RasterState {
 * \privatesection
 */

+enum class ShaderStage : uint8_t {
+    VERTEX = 0,
+    FRAGMENT = 1,
+    COMPUTE = 2
+};
+
+static constexpr size_t PIPELINE_STAGE_COUNT = 2;
+enum class ShaderStageFlags : uint8_t {
+    NONE        =    0,
+    VERTEX      =    0x1,
+    FRAGMENT    =    0x2,
+    COMPUTE     =    0x4,
+    ALL_SHADER_STAGE_FLAGS = VERTEX | FRAGMENT | COMPUTE
+};
+
+static inline constexpr bool hasShaderType(ShaderStageFlags flags, ShaderStage type) noexcept {
+    switch (type) {
+        case ShaderStage::VERTEX:
+            return bool(uint8_t(flags) & uint8_t(ShaderStageFlags::VERTEX));
+        case ShaderStage::FRAGMENT:
+            return bool(uint8_t(flags) & uint8_t(ShaderStageFlags::FRAGMENT));
+        case ShaderStage::COMPUTE:
+            return bool(uint8_t(flags) & uint8_t(ShaderStageFlags::COMPUTE));
+    }
+}
+
 /**
 * Selects which buffers to clear at the beginning of the render pass, as well as which buffers
 * can be discarded at the beginning and end of the render pass.
@@ -1310,7 +1244,7 @@ enum class Workaround : uint16_t {
    ADRENO_UNIFORM_ARRAY_CRASH,
    // Workaround a Metal pipeline compilation error with the message:
    // "Could not statically determine the target of a texture". See light_indirect.fs
-    METAL_STATIC_TEXTURE_TARGET_ERROR,
+    A8X_STATIC_TEXTURE_TARGET_ERROR,
    // Adreno drivers sometimes aren't able to blit into a layer of a texture array.
    DISABLE_BLIT_INTO_TEXTURE_ARRAY,
    // Multiple workarounds needed for PowerVR GPUs
@@ -1325,8 +1259,6 @@ template<> struct utils::EnableBitMaskOperators<filament::backend::ShaderStageFl
        : public std::true_type {};
 template<> struct utils::EnableBitMaskOperators<filament::backend::TargetBufferFlags>
        : public std::true_type {};
-template<> struct utils::EnableBitMaskOperators<filament::backend::DescriptorFlags>
-        : public std::true_type {};
 template<> struct utils::EnableBitMaskOperators<filament::backend::TextureUsage>
        : public std::true_type {};
 template<> struct utils::EnableBitMaskOperators<filament::backend::StencilFace>
--- a/filament/backend/include/backend/Handle.h
+++ b/filament/backend/include/backend/Handle.h
@@ -41,8 +41,6 @@ struct HwTexture;
 struct HwTimerQuery;
 struct HwVertexBufferInfo;
 struct HwVertexBuffer;
-struct HwDescriptorSetLayout;
-struct HwDescriptorSet;

 /*
 * A handle to a backend resource. HandleBase is for internal use only.
@@ -132,21 +130,19 @@ private:

 // Types used by the command stream
 // (we use this renaming because the macro-system doesn't deal well with "<" and ">")
-using BufferObjectHandle        = Handle<HwBufferObject>;
-using FenceHandle               = Handle<HwFence>;
-using IndexBufferHandle         = Handle<HwIndexBuffer>;
-using ProgramHandle             = Handle<HwProgram>;
-using RenderPrimitiveHandle     = Handle<HwRenderPrimitive>;
-using RenderTargetHandle        = Handle<HwRenderTarget>;
-using SamplerGroupHandle        = Handle<HwSamplerGroup>;
-using StreamHandle              = Handle<HwStream>;
-using SwapChainHandle           = Handle<HwSwapChain>;
-using TextureHandle             = Handle<HwTexture>;
-using TimerQueryHandle          = Handle<HwTimerQuery>;
-using VertexBufferHandle        = Handle<HwVertexBuffer>;
-using VertexBufferInfoHandle    = Handle<HwVertexBufferInfo>;
-using DescriptorSetLayoutHandle = Handle<HwDescriptorSetLayout>;
-using DescriptorSetHandle       = Handle<HwDescriptorSet>;
+using BufferObjectHandle     = Handle<HwBufferObject>;
+using FenceHandle            = Handle<HwFence>;
+using IndexBufferHandle      = Handle<HwIndexBuffer>;
+using ProgramHandle          = Handle<HwProgram>;
+using RenderPrimitiveHandle  = Handle<HwRenderPrimitive>;
+using RenderTargetHandle     = Handle<HwRenderTarget>;
+using SamplerGroupHandle     = Handle<HwSamplerGroup>;
+using StreamHandle           = Handle<HwStream>;
+using SwapChainHandle        = Handle<HwSwapChain>;
+using TextureHandle          = Handle<HwTexture>;
+using TimerQueryHandle       = Handle<HwTimerQuery>;
+using VertexBufferHandle     = Handle<HwVertexBuffer>;
+using VertexBufferInfoHandle = Handle<HwVertexBufferInfo>;

 } // namespace filament::backend

--- a/filament/backend/include/backend/PipelineState.h
+++ b/filament/backend/include/backend/PipelineState.h
@@ -22,23 +22,15 @@

 #include <utils/ostream.h>

-#include <array>
-
 #include <stdint.h>

 namespace filament::backend {

 //! \privatesection

-struct PipelineLayout {
-    using SetLayout = std::array<Handle<HwDescriptorSetLayout>, MAX_DESCRIPTOR_SET_COUNT>;
-    SetLayout setLayout;      // 16
-};
-
 struct PipelineState {
    Handle<HwProgram> program;                                              //  4
    Handle<HwVertexBufferInfo> vertexBufferInfo;                            //  4
-    PipelineLayout pipelineLayout;                                          // 16
    RasterState rasterState;                                                //  4
    StencilState stencilState;                                              // 12
    PolygonOffset polygonOffset;                                            //  8
--- a/filament/backend/include/backend/Program.h
+++ b/filament/backend/include/backend/Program.h
@@ -24,11 +24,9 @@

 #include <backend/DriverEnums.h>

-#include <array>
-#include <unordered_map>
-#include <tuple>
-#include <utility>
-#include <variant>
+#include <array>    // FIXME: STL headers are not allowed in public headers
+#include <utility>  // FIXME: STL headers are not allowed in public headers
+#include <variant>  // FIXME: STL headers are not allowed in public headers

 #include <stddef.h>
 #include <stdint.h>
@@ -42,36 +40,29 @@ public:
    static constexpr size_t UNIFORM_BINDING_COUNT = CONFIG_UNIFORM_BINDING_COUNT;
    static constexpr size_t SAMPLER_BINDING_COUNT = CONFIG_SAMPLER_BINDING_COUNT;

-    struct Descriptor {
-        utils::CString name;
-        backend::DescriptorType type;
-        backend::descriptor_binding_t binding;
+    struct Sampler {
+        utils::CString name = {};   // name of the sampler in the shader
+        uint32_t binding = 0;       // binding point of the sampler in the shader
    };

-    struct SpecializationConstant {
-        using Type = std::variant<int32_t, float, bool>;
-        uint32_t id;    // id set in glsl
-        Type value;     // value and type
+    struct SamplerGroupData {
+        utils::FixedCapacityVector<Sampler> samplers;
+        ShaderStageFlags stageFlags = ShaderStageFlags::ALL_SHADER_STAGE_FLAGS;
    };

-    struct Uniform { // For ES2 support
+    struct Uniform {
        utils::CString name;    // full qualified name of the uniform field
        uint16_t offset;        // offset in 'uint32_t' into the uniform buffer
        uint8_t size;           // >1 for arrays
        UniformType type;       // uniform type
    };

-    using DescriptorBindingsInfo = utils::FixedCapacityVector<Descriptor>;
-    using DescriptorSetInfo = std::array<DescriptorBindingsInfo, MAX_DESCRIPTOR_SET_COUNT>;
-    using SpecializationConstantsInfo = utils::FixedCapacityVector<SpecializationConstant>;
+    using UniformBlockInfo = std::array<utils::CString, UNIFORM_BINDING_COUNT>;
+    using UniformInfo = utils::FixedCapacityVector<Uniform>;
+    using SamplerGroupInfo = std::array<SamplerGroupData, SAMPLER_BINDING_COUNT>;
    using ShaderBlob = utils::FixedCapacityVector<uint8_t>;
    using ShaderSource = std::array<ShaderBlob, SHADER_TYPE_COUNT>;

-    using AttributesInfo = utils::FixedCapacityVector<std::pair<utils::CString, uint8_t>>;
-    using UniformInfo = utils::FixedCapacityVector<Uniform>;
-    using BindingUniformsInfo = utils::FixedCapacityVector<
-            std::tuple<uint8_t, utils::CString, Program::UniformInfo>>;
-
    Program() noexcept;

    Program(const Program& rhs) = delete;
@@ -88,19 +79,43 @@ public:
    Program& diagnostics(utils::CString const& name,
            utils::Invocable<utils::io::ostream&(utils::io::ostream& out)>&& logger);

-    // Sets one of the program's shader (e.g. vertex, fragment)
+    // sets one of the program's shader (e.g. vertex, fragment)
    // string-based shaders are null terminated, consequently the size parameter must include the
    // null terminating character.
    Program& shader(ShaderStage shader, void const* data, size_t size);

-    // Sets the language of the shader sources provided with shader() (defaults to ESSL3)
+    // sets the language of the shader sources provided with shader() (defaults to ESSL3)
    Program& shaderLanguage(ShaderLanguage shaderLanguage);

-    // Descriptor binding (set, binding, type -> shader name) info
-    Program& descriptorBindings(backend::descriptor_set_t set,
-            DescriptorBindingsInfo descriptorBindings) noexcept;
+    // Note: This is only needed for GLES3.0 backends, because the layout(binding=) syntax is
+    //       not permitted in glsl. The backend needs a way to associate a uniform block
+    //       to a binding point.
+    Program& uniformBlockBindings(
+            utils::FixedCapacityVector<std::pair<utils::CString, uint8_t>> const& uniformBlockBindings) noexcept;

-    Program& specializationConstants(SpecializationConstantsInfo specConstants) noexcept;
+    // Note: This is only needed for GLES2.0, this is used to emulate UBO. This function tells
+    // the program everything it needs to know about the uniforms at a given binding
+    Program& uniforms(uint32_t index, UniformInfo const& uniforms) noexcept;
+
+    // Note: This is only needed for GLES2.0.
+    Program& attributes(
+            utils::FixedCapacityVector<std::pair<utils::CString, uint8_t>> attributes) noexcept;
+
+    // sets the 'bindingPoint' sampler group descriptor for this program.
+    // 'samplers' can be destroyed after this call.
+    // This effectively associates a set of (BindingPoints, index) to a texture unit in the shader.
+    // Or more precisely, what layout(binding=) is set to in GLSL.
+    Program& setSamplerGroup(size_t bindingPoint, ShaderStageFlags stageFlags,
+            Sampler const* samplers, size_t count) noexcept;
+
+    struct SpecializationConstant {
+        using Type = std::variant<int32_t, float, bool>;
+        uint32_t id;                                // id set in glsl
+        Type value;                                 // value and type
+    };
+
+    Program& specializationConstants(
+            utils::FixedCapacityVector<SpecializationConstant> specConstants) noexcept;

    struct PushConstant {
        utils::CString name;
@@ -114,40 +129,33 @@ public:

    Program& multiview(bool multiview) noexcept;

-    // For ES2 support only...
-    Program& uniforms(uint32_t index, utils::CString name, UniformInfo uniforms) noexcept;
-    Program& attributes(AttributesInfo attributes) noexcept;
-
-    //
-    // Getters for program construction...
-    //
-
    ShaderSource const& getShadersSource() const noexcept { return mShadersSource; }
    ShaderSource& getShadersSource() noexcept { return mShadersSource; }

+    UniformBlockInfo const& getUniformBlockBindings() const noexcept { return mUniformBlocks; }
+    UniformBlockInfo& getUniformBlockBindings() noexcept { return mUniformBlocks; }
+
+    SamplerGroupInfo const& getSamplerGroupInfo() const { return mSamplerGroups; }
+    SamplerGroupInfo& getSamplerGroupInfo() { return mSamplerGroups; }
+
+    auto const& getBindingUniformInfo() const { return mBindingUniformInfo; }
+    auto& getBindingUniformInfo() { return mBindingUniformInfo; }
+
+    auto const& getAttributes() const { return mAttributes; }
+    auto& getAttributes() { return mAttributes; }
+
    utils::CString const& getName() const noexcept { return mName; }
    utils::CString& getName() noexcept { return mName; }

    auto const& getShaderLanguage() const { return mShaderLanguage; }

-    uint64_t getCacheId() const noexcept { return mCacheId; }
-
-    bool isMultiview() const noexcept { return mMultiview; }
-
-    CompilerPriorityQueue getPriorityQueue() const noexcept { return mPriorityQueue; }
-
-    SpecializationConstantsInfo const& getSpecializationConstants() const noexcept {
+    utils::FixedCapacityVector<SpecializationConstant> const& getSpecializationConstants() const noexcept {
        return mSpecializationConstants;
    }
-
-    SpecializationConstantsInfo& getSpecializationConstants() noexcept {
+    utils::FixedCapacityVector<SpecializationConstant>& getSpecializationConstants() noexcept {
        return mSpecializationConstants;
    }

-    DescriptorSetInfo& getDescriptorBindings() noexcept {
-        return mDescriptorBindings;
-    }
-
    utils::FixedCapacityVector<PushConstant> const& getPushConstants(
            ShaderStage stage) const noexcept {
        return mPushConstants[static_cast<uint8_t>(stage)];
@@ -157,29 +165,27 @@ public:
        return mPushConstants[static_cast<uint8_t>(stage)];
    }

-    auto const& getBindingUniformInfo() const { return mBindingUniformsInfo; }
-    auto& getBindingUniformInfo() { return mBindingUniformsInfo; }
+    uint64_t getCacheId() const noexcept { return mCacheId; }

-    auto const& getAttributes() const { return mAttributes; }
-    auto& getAttributes() { return mAttributes; }
+    bool isMultiview() const noexcept { return mMultiview; }
+
+    CompilerPriorityQueue getPriorityQueue() const noexcept { return mPriorityQueue; }

 private:
    friend utils::io::ostream& operator<<(utils::io::ostream& out, const Program& builder);

+    UniformBlockInfo mUniformBlocks = {};
+    SamplerGroupInfo mSamplerGroups = {};
    ShaderSource mShadersSource;
    ShaderLanguage mShaderLanguage = ShaderLanguage::ESSL3;
    utils::CString mName;
    uint64_t mCacheId{};
-    CompilerPriorityQueue mPriorityQueue = CompilerPriorityQueue::HIGH;
    utils::Invocable<utils::io::ostream&(utils::io::ostream& out)> mLogger;
-    SpecializationConstantsInfo mSpecializationConstants;
+    utils::FixedCapacityVector<SpecializationConstant> mSpecializationConstants;
    std::array<utils::FixedCapacityVector<PushConstant>, SHADER_TYPE_COUNT> mPushConstants;
-    DescriptorSetInfo mDescriptorBindings;
-
-    // For ES2 support only
-    AttributesInfo mAttributes;
-    BindingUniformsInfo mBindingUniformsInfo;
-
+    utils::FixedCapacityVector<std::pair<utils::CString, uint8_t>> mAttributes;
+    std::array<UniformInfo, Program::UNIFORM_BINDING_COUNT> mBindingUniformInfo;
+    CompilerPriorityQueue mPriorityQueue = CompilerPriorityQueue::HIGH;
    // Indicates the current engine was initialized with multiview stereo, and the variant for this
    // program contains STE flag. This will be referred later for the OpenGL shader compiler to
    // determine whether shader code replacement for the num_views should be performed.
--- a/filament/backend/include/private/backend/Driver.h
+++ b/filament/backend/include/private/backend/Driver.h
@@ -18,7 +18,6 @@
 #define TNT_FILAMENT_BACKEND_PRIVATE_DRIVER_H

 #include <backend/CallbackHandler.h>
-#include <backend/DescriptorSetOffsetArray.h>
 #include <backend/DriverApiForward.h>
 #include <backend/DriverEnums.h>
 #include <backend/Handle.h>
--- a/filament/backend/include/private/backend/DriverAPI.inc
+++ b/filament/backend/include/private/backend/DriverAPI.inc
@@ -162,10 +162,6 @@ DECL_DRIVER_API_0(finish)
 // reset state tracking, if the driver does any state tracking (e.g. GL)
 DECL_DRIVER_API_0(resetState)

-DECL_DRIVER_API_N(setDebugTag,
-        backend::HandleBase::HandleId, handleId,
-        utils::CString, tag)
-
 /*
 * Creating driver objects
 * -----------------------
@@ -200,33 +196,20 @@ DECL_DRIVER_API_R_N(backend::TextureHandle, createTexture,
        uint32_t, depth,
        backend::TextureUsage, usage)

-DECL_DRIVER_API_R_N(backend::TextureHandle, createTextureView,
-        backend::TextureHandle, texture,
-        uint8_t, baseLevel,
-        uint8_t, levelCount)
-
-DECL_DRIVER_API_R_N(backend::TextureHandle, createTextureViewSwizzle,
-        backend::TextureHandle, texture,
+DECL_DRIVER_API_R_N(backend::TextureHandle, createTextureSwizzled,
+        backend::SamplerType, target,
+        uint8_t, levels,
+        backend::TextureFormat, format,
+        uint8_t, samples,
+        uint32_t, width,
+        uint32_t, height,
+        uint32_t, depth,
+        backend::TextureUsage, usage,
        backend::TextureSwizzle, r,
        backend::TextureSwizzle, g,
        backend::TextureSwizzle, b,
        backend::TextureSwizzle, a)

-DECL_DRIVER_API_R_N(backend::TextureHandle, createTextureExternalImage,
-        backend::TextureFormat, format,
-        uint32_t, width,
-        uint32_t, height,
-        backend::TextureUsage, usage,
-        void*, image)
-
-DECL_DRIVER_API_R_N(backend::TextureHandle, createTextureExternalImagePlane,
-        backend::TextureFormat, format,
-        uint32_t, width,
-        uint32_t, height,
-        backend::TextureUsage, usage,
-        void*, image,
-        uint32_t, plane)
-
 DECL_DRIVER_API_R_N(backend::TextureHandle, importTexture,
        intptr_t, id,
        backend::SamplerType, target,
@@ -238,6 +221,9 @@ DECL_DRIVER_API_R_N(backend::TextureHandle, importTexture,
        uint32_t, depth,
        backend::TextureUsage, usage)

+DECL_DRIVER_API_R_N(backend::SamplerGroupHandle, createSamplerGroup,
+        uint32_t, size, utils::FixedSizeString<32>, debugName)
+
 DECL_DRIVER_API_R_N(backend::RenderPrimitiveHandle, createRenderPrimitive,
        backend::VertexBufferHandle, vbh,
        backend::IndexBufferHandle, ibh,
@@ -271,53 +257,25 @@ DECL_DRIVER_API_R_N(backend::SwapChainHandle, createSwapChainHeadless,

 DECL_DRIVER_API_R_0(backend::TimerQueryHandle, createTimerQuery)

-DECL_DRIVER_API_R_N(backend::DescriptorSetLayoutHandle, createDescriptorSetLayout,
-        backend::DescriptorSetLayout&&, info)
-
-DECL_DRIVER_API_R_N(backend::DescriptorSetHandle, createDescriptorSet,
-        backend::DescriptorSetLayoutHandle, dslh)
-
-DECL_DRIVER_API_N(updateDescriptorSetBuffer,
-        backend::DescriptorSetHandle, dsh,
-        backend::descriptor_binding_t, binding,
-        backend::BufferObjectHandle, boh,
-        uint32_t, offset,
-        uint32_t, size
-)
-
-DECL_DRIVER_API_N(updateDescriptorSetTexture,
-        backend::DescriptorSetHandle, dsh,
-        backend::descriptor_binding_t, binding,
-        backend::TextureHandle, th,
-        SamplerParams, params
-)
-
-DECL_DRIVER_API_N(bindDescriptorSet,
-        backend::DescriptorSetHandle, dsh,
-        backend::descriptor_set_t, set,
-        backend::DescriptorSetOffsetArray&&, offsets
-)
-

 /*
 * Destroying driver objects
 * -------------------------
 */

-DECL_DRIVER_API_N(destroyVertexBuffer,          backend::VertexBufferHandle, vbh)
-DECL_DRIVER_API_N(destroyVertexBufferInfo,      backend::VertexBufferInfoHandle, vbih)
-DECL_DRIVER_API_N(destroyIndexBuffer,           backend::IndexBufferHandle, ibh)
-DECL_DRIVER_API_N(destroyBufferObject,          backend::BufferObjectHandle, ibh)
-DECL_DRIVER_API_N(destroyRenderPrimitive,       backend::RenderPrimitiveHandle, rph)
-DECL_DRIVER_API_N(destroyProgram,               backend::ProgramHandle, ph)
-DECL_DRIVER_API_N(destroyTexture,               backend::TextureHandle, th)
-DECL_DRIVER_API_N(destroyRenderTarget,          backend::RenderTargetHandle, rth)
-DECL_DRIVER_API_N(destroySwapChain,             backend::SwapChainHandle, sch)
-DECL_DRIVER_API_N(destroyStream,                backend::StreamHandle, sh)
-DECL_DRIVER_API_N(destroyTimerQuery,            backend::TimerQueryHandle, sh)
-DECL_DRIVER_API_N(destroyFence,                 backend::FenceHandle, fh)
-DECL_DRIVER_API_N(destroyDescriptorSetLayout,   backend::DescriptorSetLayoutHandle, dslh)
-DECL_DRIVER_API_N(destroyDescriptorSet,         backend::DescriptorSetHandle, dsh)
+DECL_DRIVER_API_N(destroyVertexBuffer,    backend::VertexBufferHandle, vbh)
+DECL_DRIVER_API_N(destroyVertexBufferInfo,backend::VertexBufferInfoHandle, vbih)
+DECL_DRIVER_API_N(destroyIndexBuffer,     backend::IndexBufferHandle, ibh)
+DECL_DRIVER_API_N(destroyBufferObject,    backend::BufferObjectHandle, ibh)
+DECL_DRIVER_API_N(destroyRenderPrimitive, backend::RenderPrimitiveHandle, rph)
+DECL_DRIVER_API_N(destroyProgram,         backend::ProgramHandle, ph)
+DECL_DRIVER_API_N(destroySamplerGroup,    backend::SamplerGroupHandle, sbh)
+DECL_DRIVER_API_N(destroyTexture,         backend::TextureHandle, th)
+DECL_DRIVER_API_N(destroyRenderTarget,    backend::RenderTargetHandle, rth)
+DECL_DRIVER_API_N(destroySwapChain,       backend::SwapChainHandle, sch)
+DECL_DRIVER_API_N(destroyStream,          backend::StreamHandle, sh)
+DECL_DRIVER_API_N(destroyTimerQuery,      backend::TimerQueryHandle, sh)
+DECL_DRIVER_API_N(destroyFence,           backend::FenceHandle, fh)

 /*
 * Synchronous APIs
@@ -347,7 +305,6 @@ DECL_DRIVER_API_SYNCHRONOUS_0(bool, isParallelShaderCompileSupported)
 DECL_DRIVER_API_SYNCHRONOUS_0(bool, isDepthStencilResolveSupported)
 DECL_DRIVER_API_SYNCHRONOUS_N(bool, isDepthStencilBlitSupported, backend::TextureFormat, format)
 DECL_DRIVER_API_SYNCHRONOUS_0(bool, isProtectedTexturesSupported)
-DECL_DRIVER_API_SYNCHRONOUS_0(bool, isDepthClampSupported)
 DECL_DRIVER_API_SYNCHRONOUS_0(uint8_t, getMaxDrawBuffers)
 DECL_DRIVER_API_SYNCHRONOUS_0(size_t, getMaxUniformBufferSize)
 DECL_DRIVER_API_SYNCHRONOUS_0(math::float2, getClipSpaceParams)
@@ -384,6 +341,15 @@ DECL_DRIVER_API_N(updateBufferObjectUnsynchronized,
 DECL_DRIVER_API_N(resetBufferObject,
        backend::BufferObjectHandle, ibh)

+DECL_DRIVER_API_N(updateSamplerGroup,
+        backend::SamplerGroupHandle, ubh,
+        backend::BufferDescriptor&&, data)
+
+DECL_DRIVER_API_N(setMinMaxLevels,
+        backend::TextureHandle, th,
+        uint32_t, minLevel,
+        uint32_t, maxLevel)
+
 DECL_DRIVER_API_N(update3DImage,
        backend::TextureHandle, th,
        uint32_t, level,
@@ -398,12 +364,10 @@ DECL_DRIVER_API_N(update3DImage,
 DECL_DRIVER_API_N(generateMipmaps,
        backend::TextureHandle, th)

-// Deprecated
 DECL_DRIVER_API_N(setExternalImage,
        backend::TextureHandle, th,
        void*, image)

-// Deprecated
 DECL_DRIVER_API_N(setExternalImagePlane,
        backend::TextureHandle, th,
        void*, image,
@@ -450,16 +414,37 @@ DECL_DRIVER_API_N(commit,
 * -----------------------
 */

+DECL_DRIVER_API_N(bindUniformBuffer,
+        uint32_t, index,
+        backend::BufferObjectHandle, ubh)
+
+DECL_DRIVER_API_N(bindBufferRange,
+        BufferObjectBinding, bindingType,
+        uint32_t, index,
+        backend::BufferObjectHandle, ubh,
+        uint32_t, offset,
+        uint32_t, size)
+
+DECL_DRIVER_API_N(unbindBuffer,
+        BufferObjectBinding, bindingType,
+        uint32_t, index)
+
+DECL_DRIVER_API_N(bindSamplers,
+        uint32_t, index,
+        backend::SamplerGroupHandle, sbh)
+
 DECL_DRIVER_API_N(setPushConstant,
        backend::ShaderStage, stage,
        uint8_t, index,
        backend::PushConstantVariant, value)

 DECL_DRIVER_API_N(insertEventMarker,
-        const char*, string)
+        const char*, string,
+        uint32_t, len = 0)

 DECL_DRIVER_API_N(pushGroupMarker,
-        const char*, string)
+        const char*, string,
+        uint32_t, len = 0)

 DECL_DRIVER_API_0(popGroupMarker)

--- a/filament/backend/include/private/backend/DriverApi.h
+++ b/filament/backend/include/private/backend/DriverApi.h
@@ -18,17 +18,6 @@
 #define TNT_FILAMENT_BACKEND_PRIVATE_DRIVERAPI_H

 #include "backend/DriverApiForward.h"
-
 #include "private/backend/CommandStream.h"

-#include <stddef.h>
-
-namespace filament::backend {
-
-inline void* allocateFromCommandStream(DriverApi& driver, size_t size, size_t alignment) noexcept {
-    return driver.allocate(size, alignment);
-}
-
-} // namespace filament::backend
-
 #endif // TNT_FILAMENT_BACKEND_PRIVATE_DRIVERAPI_H
--- a/filament/backend/include/private/backend/HandleAllocator.h
+++ b/filament/backend/include/private/backend/HandleAllocator.h
@@ -20,12 +20,11 @@
 #include <backend/Handle.h>

 #include <utils/Allocator.h>
-#include <utils/CString.h>
 #include <utils/Log.h>
-#include <utils/Panic.h>
 #include <utils/compiler.h>
 #include <utils/debug.h>
 #include <utils/ostream.h>
+#include <utils/Panic.h>

 #include <tsl/robin_map.h>

@@ -38,9 +37,9 @@
 #include <stddef.h>
 #include <stdint.h>

-#define HandleAllocatorGL  HandleAllocator<32,  96, 136>    // ~4520 / pool / MiB
+#define HandleAllocatorGL  HandleAllocator<32,  64, 136>    // ~4520 / pool / MiB
 #define HandleAllocatorVK  HandleAllocator<64, 160, 312>    // ~1820 / pool / MiB
-#define HandleAllocatorMTL HandleAllocator<32,  64, 552>    // ~1660 / pool / MiB
+#define HandleAllocatorMTL HandleAllocator<32,  48, 552>    // ~1660 / pool / MiB

 namespace filament::backend {

@@ -174,10 +173,8 @@ public:
                uint8_t const age = (tag & HANDLE_AGE_MASK) >> HANDLE_AGE_SHIFT;
                auto const pNode = static_cast<typename Allocator::Node*>(p);
                uint8_t const expectedAge = pNode[-1].age;
-                // getHandleTag() is only called if the check fails.
-                FILAMENT_CHECK_POSTCONDITION(expectedAge == age)
-                        << "use-after-free of Handle with id=" << handle.getId()
-                        << ", tag=" << getHandleTag(handle.getId()).c_str_safe();
+                FILAMENT_CHECK_POSTCONDITION(expectedAge == age) <<
+                        "use-after-free of Handle with id=" << handle.getId();
            }
        }

@@ -204,29 +201,6 @@ public:
        return handle_cast<Dp>(const_cast<Handle<B>&>(handle));
    }

-    void associateTagToHandle(HandleBase::HandleId id, utils::CString&& tag) noexcept {
-        // TODO: for now, only pool handles check for use-after-free, so we only keep tags for
-        // those
-        if (isPoolHandle(id)) {
-            // Truncate the age to get the debug tag
-            uint32_t const key = id & ~(HANDLE_DEBUG_TAG_MASK ^ HANDLE_AGE_MASK);
-            // This line is the costly part. In the future, we could potentially use a custom
-            // allocator.
-            mDebugTags[key] = std::move(tag);
-        }
-    }
-
-    utils::CString getHandleTag(HandleBase::HandleId id) const noexcept {
-        if (!isPoolHandle(id)) {
-            return "(no tag)";
-        }
-        uint32_t const key = id & ~(HANDLE_DEBUG_TAG_MASK ^ HANDLE_AGE_MASK);
-        if (auto pos = mDebugTags.find(key); pos != mDebugTags.end()) {
-            return pos->second;
-        }
-        return "(no tag)";
-    }
-
 private:

    template<typename D>
@@ -344,24 +318,12 @@ private:
        }
    }

-    // number if bits allotted to the handle's age (currently 4 max)
-    static constexpr uint32_t HANDLE_AGE_BIT_COUNT = 4;
-    // number if bits allotted to the handle's debug tag (HANDLE_AGE_BIT_COUNT max)
-    static constexpr uint32_t HANDLE_DEBUG_TAG_BIT_COUNT = 2;
-    // bit shift for both the age and debug tag
-    static constexpr uint32_t HANDLE_AGE_SHIFT = 27;
-    // mask for the heap (vs pool) flag
-    static constexpr uint32_t HANDLE_HEAP_FLAG = 0x80000000u;
-    // mask for the age
-    static constexpr uint32_t HANDLE_AGE_MASK =
-            ((1 << HANDLE_AGE_BIT_COUNT) - 1) << HANDLE_AGE_SHIFT;
-    // mask for the debug tag
-    static constexpr uint32_t HANDLE_DEBUG_TAG_MASK =
-            ((1 << HANDLE_DEBUG_TAG_BIT_COUNT) - 1) << HANDLE_AGE_SHIFT;
-    // mask for the index
-    static constexpr uint32_t HANDLE_INDEX_MASK = 0x07FFFFFFu;
-
-    static_assert(HANDLE_DEBUG_TAG_BIT_COUNT <= HANDLE_AGE_BIT_COUNT);
+    // we handle a 4 bits age per address
+    static constexpr uint32_t HANDLE_HEAP_FLAG      = 0x80000000u;      // pool vs heap handle
+    static constexpr uint32_t HANDLE_AGE_MASK       = 0x78000000u;      // handle's age
+    static constexpr uint32_t HANDLE_INDEX_MASK     = 0x07FFFFFFu;      // handle index
+    static constexpr uint32_t HANDLE_TAG_MASK       = HANDLE_AGE_MASK;
+    static constexpr uint32_t HANDLE_AGE_SHIFT      = 27;

    static bool isPoolHandle(HandleBase::HandleId id) noexcept {
        return (id & HANDLE_HEAP_FLAG) == 0u;
@@ -376,7 +338,7 @@ private:
        // a non-pool handle.
        if (UTILS_LIKELY(isPoolHandle(id))) {
            char* const base = (char*)mHandleArena.getArea().begin();
-            uint32_t const tag = id & HANDLE_AGE_MASK;
+            uint32_t const tag = id & HANDLE_TAG_MASK;
            size_t const offset = (id & HANDLE_INDEX_MASK) * Allocator::getAlignment();
            return { static_cast<void*>(base + offset), tag };
        }
@@ -391,7 +353,7 @@ private:
        size_t const offset = (char*)p - base;
        assert_invariant((offset % Allocator::getAlignment()) == 0);
        auto id = HandleBase::HandleId(offset / Allocator::getAlignment());
-        id |= tag & HANDLE_AGE_MASK;
+        id |= tag & HANDLE_TAG_MASK;
        assert_invariant((id & HANDLE_HEAP_FLAG) == 0);
        return id;
    }
@@ -401,7 +363,6 @@ private:
    // Below is only used when running out of space in the HandleArena
    mutable utils::Mutex mLock;
    tsl::robin_map<HandleBase::HandleId, void*> mOverflowMap;
-    tsl::robin_map<HandleBase::HandleId, utils::CString> mDebugTags;
    HandleBase::HandleId mId = 0;
    bool mUseAfterFreeCheckDisabled = false;
 };
--- a/filament/backend/src/CircularBuffer.cpp
+++ b/filament/backend/src/CircularBuffer.cpp
@@ -24,7 +24,7 @@
 #include <utils/debug.h>
 #include <utils/ostream.h>

-#if !defined(WIN32) && !defined(__EMSCRIPTEN__)
+#if !defined(WIN32) && !defined(__EMSCRIPTEN__) && !defined(IOS)
 #    include <sys/mman.h>
 #    include <unistd.h>
 #    define HAS_MMAP 1
--- a/filament/backend/src/CommandBufferQueue.cpp
+++ b/filament/backend/src/CommandBufferQueue.cpp
@@ -101,8 +101,9 @@ void CommandBufferQueue::flush() noexcept {
    size_t const used = std::distance(
            static_cast<char const*>(begin), static_cast<char const*>(end));

-
    std::unique_lock<utils::Mutex> lock(mLock);
+    mCommandBuffersToExecute.push_back({ begin, end });
+    mCondition.notify_one();

    // circular buffer is too small, we corrupted the stream
    FILAMENT_CHECK_POSTCONDITION(used <= mFreeSpace) <<
@@ -111,13 +112,11 @@ void CommandBufferQueue::flush() noexcept {
            "Space used at this time: " << used <<
            " bytes, overflow: " << used - mFreeSpace << " bytes";

-    mFreeSpace -= used;
-    mCommandBuffersToExecute.push_back({ begin, end });
-    mCondition.notify_one();
-
    // wait until there is enough space in the buffer
+    mFreeSpace -= used;
    if (UTILS_UNLIKELY(mFreeSpace < requiredSize)) {

+
 #ifndef NDEBUG
        size_t const totalUsed = circularBuffer.size() - mFreeSpace;
        slog.d << "CommandStream used too much space (will block): "
@@ -154,10 +153,8 @@ std::vector<CommandBufferQueue::Range> CommandBufferQueue::waitForCommands() con
 }

 void CommandBufferQueue::releaseBuffer(CommandBufferQueue::Range const& buffer) {
-    size_t const used = std::distance(
-            static_cast<char const*>(buffer.begin), static_cast<char const*>(buffer.end));
    std::lock_guard<utils::Mutex> const lock(mLock);
-    mFreeSpace += used;
+    mFreeSpace += uintptr_t(buffer.end) - uintptr_t(buffer.begin);
    mCondition.notify_one();
 }

--- a/filament/backend/src/CommandStream.cpp
+++ b/filament/backend/src/CommandStream.cpp
@@ -20,16 +20,11 @@
 #include <utils/CallStack.h>
 #endif

-#include <utils/compiler.h>
 #include <utils/Log.h>
-#include <utils/ostream.h>
 #include <utils/Profiler.h>
 #include <utils/Systrace.h>

-#include <cstddef>
 #include <functional>
-#include <string>
-#include <utility>

 #ifdef __ANDROID__
 #include <sys/system_properties.h>
@@ -79,8 +74,8 @@ CommandStream::CommandStream(Driver& driver, CircularBuffer& buffer) noexcept
 }

 void CommandStream::execute(void* buffer) {
-    // NOTE: we can't use SYSTRACE_CALL() or similar here because, execute() below, also
-    // uses systrace BEGIN/END and the END is not guaranteed to be happening in this scope.
+    SYSTRACE_CALL();
+    SYSTRACE_CONTEXT();

    Profiler profiler;

@@ -105,7 +100,6 @@ void CommandStream::execute(void* buffer) {
            // we want to remove all this when tracing is completely disabled
            profiler.stop();
            UTILS_UNUSED Profiler::Counters const counters = profiler.readCounters();
-            SYSTRACE_CONTEXT();
            SYSTRACE_VALUE32("GLThread (I)", counters.getInstructions());
            SYSTRACE_VALUE32("GLThread (C)", counters.getCpuCycles());
            SYSTRACE_VALUE32("GLThread (CPI x10)", counters.getCPI() * 10);
--- a/filament/backend/src/DriverBase.h
+++ b/filament/backend/src/DriverBase.h
@@ -101,14 +101,6 @@ struct HwProgram : public HwBase {
    HwProgram() noexcept = default;
 };

-struct HwDescriptorSetLayout : public HwBase {
-    HwDescriptorSetLayout() noexcept = default;
-};
-
-struct HwDescriptorSet : public HwBase {
-    HwDescriptorSet() noexcept = default;
-};
-
 struct HwSamplerGroup : public HwBase {
    HwSamplerGroup() noexcept = default;
 };
--- a/filament/backend/src/HandleAllocator.cpp
+++ b/filament/backend/src/HandleAllocator.cpp
@@ -80,9 +80,6 @@ HandleAllocator<P0, P1, P2>::HandleAllocator(const char* name, size_t size,
        bool disableUseAfterFreeCheck) noexcept
    : mHandleArena(name, size, disableUseAfterFreeCheck),
      mUseAfterFreeCheckDisabled(disableUseAfterFreeCheck) {
-    // Reserve initial space for debug tags. This prevents excessive calls to malloc when the first
-    // few tags are set.
-    mDebugTags.reserve(512);
 }

 template <size_t P0, size_t P1, size_t P2>
--- a/filament/backend/src/Program.cpp
+++ b/filament/backend/src/Program.cpp
@@ -14,18 +14,7 @@
 * limitations under the License.
 */

-#include <backend/Program.h>
-#include <backend/DriverEnums.h>
-
-#include <utils/debug.h>
-#include <utils/CString.h>
-#include <utils/ostream.h>
-#include <utils/Invocable.h>
-
-#include <utility>
-
-#include <stddef.h>
-#include <stdint.h>
+#include "backend/Program.h"

 namespace filament::backend {

@@ -63,24 +52,41 @@ Program& Program::shaderLanguage(ShaderLanguage shaderLanguage) {
    return *this;
 }

-Program& Program::descriptorBindings(backend::descriptor_set_t set,
-        DescriptorBindingsInfo descriptorBindings) noexcept {
-    mDescriptorBindings[set] = std::move(descriptorBindings);
+Program& Program::uniformBlockBindings(
+        FixedCapacityVector<std::pair<utils::CString, uint8_t>> const& uniformBlockBindings) noexcept {
+    for (auto const& item : uniformBlockBindings) {
+        assert_invariant(item.second < UNIFORM_BINDING_COUNT);
+        mUniformBlocks[item.second] = item.first;
+    }
    return *this;
 }

-Program& Program::uniforms(uint32_t index, utils::CString name, UniformInfo uniforms) noexcept {
-    mBindingUniformsInfo.reserve(mBindingUniformsInfo.capacity() + 1);
-    mBindingUniformsInfo.emplace_back(index, std::move(name), std::move(uniforms));
+Program& Program::uniforms(uint32_t index, UniformInfo const& uniforms) noexcept {
+    assert_invariant(index < UNIFORM_BINDING_COUNT);
+    mBindingUniformInfo[index] = uniforms;
    return *this;
 }

-Program& Program::attributes(AttributesInfo attributes) noexcept {
+
+Program& Program::attributes(
+        utils::FixedCapacityVector<std::pair<utils::CString, uint8_t>> attributes) noexcept {
    mAttributes = std::move(attributes);
    return *this;
 }

-Program& Program::specializationConstants(SpecializationConstantsInfo specConstants) noexcept {
+Program& Program::setSamplerGroup(size_t bindingPoint, ShaderStageFlags stageFlags,
+        const Program::Sampler* samplers, size_t count) noexcept {
+    auto& groupData = mSamplerGroups[bindingPoint];
+    groupData.stageFlags = stageFlags;
+    auto& samplerList = groupData.samplers;
+    samplerList.reserve(count);
+    samplerList.resize(count);
+    std::copy_n(samplers, count, samplerList.data());
+    return *this;
+}
+
+Program& Program::specializationConstants(
+        FixedCapacityVector<SpecializationConstant> specConstants) noexcept {
    mSpecializationConstants = std::move(specConstants);
    return *this;
 }
--- a/filament/backend/src/metal/MetalBuffer.h
+++ b/filament/backend/src/metal/MetalBuffer.h
@@ -160,8 +160,6 @@ public:
         size_t size, bool forceGpuBuffer = false);
    ~MetalBuffer();

-    [[nodiscard]] bool wasAllocationSuccessful() const noexcept { return mBuffer || mCpuBuffer; }
-
    MetalBuffer(const MetalBuffer& rhs) = delete;
    MetalBuffer& operator=(const MetalBuffer& rhs) = delete;

@@ -182,7 +180,7 @@ public:
     * is no device allocation.
     *
     */
-    id<MTLBuffer> getGpuBufferForDraw() noexcept;
+    id<MTLBuffer> getGpuBufferForDraw(id<MTLCommandBuffer> cmdBuffer) noexcept;

    void* getCpuBuffer() const noexcept { return mCpuBuffer; }

--- a/filament/backend/src/metal/MetalBuffer.mm
+++ b/filament/backend/src/metal/MetalBuffer.mm
@@ -40,15 +40,12 @@ MetalBuffer::MetalBuffer(MetalContext& context, BufferObjectBinding bindingType,
    // If the buffer is less than 4K in size and is updated frequently, we don't use an explicit
    // buffer. Instead, we use immediate command encoder methods like setVertexBytes:length:atIndex:.
    // This won't work for SSBOs, since they are read/write.
-
-    /*
    if (size <= 4 * 1024 && bindingType != BufferObjectBinding::SHADER_STORAGE &&
            usage == BufferUsage::DYNAMIC && !forceGpuBuffer) {
        mBuffer = nil;
        mCpuBuffer = malloc(size);
        return;
    }
-    */

    // Otherwise, we allocate a private GPU buffer.
    {
@@ -56,8 +53,8 @@ MetalBuffer::MetalBuffer(MetalContext& context, BufferObjectBinding bindingType,
        mBuffer = { [context.device newBufferWithLength:size options:MTLResourceStorageModePrivate],
            TrackedMetalBuffer::Type::GENERIC };
    }
-    // mBuffer might fail to be allocated. Clients can check for this by calling
-    // wasAllocationSuccessful().
+    FILAMENT_CHECK_POSTCONDITION(mBuffer)
+            << "Could not allocate Metal buffer of size " << size << ".";
 }

 MetalBuffer::~MetalBuffer() {
@@ -97,7 +94,7 @@ void MetalBuffer::copyIntoBufferUnsynchronized(void* src, size_t size, size_t by
    copyIntoBuffer(src, size, byteOffset);
 }

-id<MTLBuffer> MetalBuffer::getGpuBufferForDraw() noexcept {
+id<MTLBuffer> MetalBuffer::getGpuBufferForDraw(id<MTLCommandBuffer> cmdBuffer) noexcept {
    // If there's a CPU buffer, then we return nil here, as the CPU-side buffer will be bound
    // separately.
    if (mCpuBuffer) {
@@ -140,7 +137,7 @@ void MetalBuffer::bindBuffers(id<MTLCommandBuffer> cmdBuffer, id<MTLCommandEncod
        }
        // getGpuBufferForDraw() might return nil, which means there isn't a device allocation for
        // this buffer. In this case, we'll bind the buffer below with the CPU-side memory.
-        id<MTLBuffer> gpuBuffer = buffer->getGpuBufferForDraw();
+        id<MTLBuffer> gpuBuffer = buffer->getGpuBufferForDraw(cmdBuffer);
        if (!gpuBuffer) {
            continue;
        }
--- a/filament/backend/src/metal/MetalContext.h
+++ b/filament/backend/src/metal/MetalContext.h
@@ -21,8 +21,6 @@
 #include "MetalShaderCompiler.h"
 #include "MetalState.h"

-#include <backend/DriverEnums.h>
-
 #include <CoreVideo/CVMetalTextureCache.h>
 #include <Metal/Metal.h>
 #include <QuartzCore/QuartzCore.h>
@@ -48,13 +46,13 @@ class MetalBlitter;
 class MetalBufferPool;
 class MetalBumpAllocator;
 class MetalRenderTarget;
+class MetalSamplerGroup;
 class MetalSwapChain;
 class MetalTexture;
 class MetalTimerQueryInterface;
 struct MetalUniformBuffer;
 struct MetalIndexBuffer;
 struct MetalVertexBuffer;
-struct MetalDescriptorSet;

 constexpr static uint8_t MAX_SAMPLE_COUNT = 8;  // Metal devices support at most 8 MSAA samples

@@ -70,53 +68,6 @@ private:
    bool mDirty = false;
 };

-class MetalDynamicOffsets {
-public:
-    void setOffsets(uint32_t set, const uint32_t* offsets, uint32_t count) {
-        assert(set < MAX_DESCRIPTOR_SET_COUNT);
-
-        auto getStartIndexForSet = [&](uint32_t s) {
-            uint32_t startIndex = 0;
-            for (uint32_t i = 0; i < s; i++) {
-                startIndex += mCounts[i];
-            }
-            return startIndex;
-        };
-
-        const bool resizeNecessary = mCounts[set] != count;
-        if (UTILS_UNLIKELY(resizeNecessary)) {
-            int delta = count - mCounts[set];
-
-            auto thisSetStart = mOffsets.begin() + getStartIndexForSet(set);
-            if (delta > 0) {
-                mOffsets.insert(thisSetStart, delta, 0);
-            } else {
-                mOffsets.erase(thisSetStart, thisSetStart - delta);
-            }
-
-            mCounts[set] = count;
-        }
-
-        if (resizeNecessary ||
-                !std::equal(
-                        offsets, offsets + count, mOffsets.begin() + getStartIndexForSet(set))) {
-            std::copy(offsets, offsets + count, mOffsets.begin() + getStartIndexForSet(set));
-            mDirty = true;
-        }
-    }
-    bool isDirty() const { return mDirty; }
-    void setDirty(bool dirty) { mDirty = dirty; }
-
-    std::pair<uint32_t, const uint32_t*> getOffsets() const {
-        return { mOffsets.size(), mOffsets.data() };
-    }
-
-private:
-    std::array<uint32_t, MAX_DESCRIPTOR_SET_COUNT> mCounts = { 0 };
-    std::vector<uint32_t> mOffsets;
-    bool mDirty = false;
-};
-
 struct MetalContext {
    explicit MetalContext(size_t metalFreedTextureListSize)
        : texturesToDestroy(metalFreedTextureListSize) {}
@@ -125,12 +76,8 @@ struct MetalContext {
    id<MTLDevice> device = nullptr;
    id<MTLCommandQueue> commandQueue = nullptr;

-    // The ID of pendingCommandBuffer (or the next command buffer, if pendingCommandBuffer is nil).
-    uint64_t pendingCommandBufferId = 1;
-    // read from driver thread, set from completion handlers
-    std::atomic<uint64_t> latestCompletedCommandBufferId = 0;
-    id<MTLCommandBuffer> pendingCommandBuffer = nil;
-    id<MTLRenderCommandEncoder> currentRenderPassEncoder = nil;
+    id<MTLCommandBuffer> pendingCommandBuffer = nullptr;
+    id<MTLRenderCommandEncoder> currentRenderPassEncoder = nullptr;

    std::atomic<bool> memorylessLimitsReached = false;

@@ -146,7 +93,7 @@ struct MetalContext {
    } highestSupportedGpuFamily;

    struct {
-        bool staticTextureTargetError;
+        bool a8xStaticTextureTargetError;
    } bugs;

    // sampleCountLookup[requestedSamples] gives a <= sample count supported by the device.
@@ -161,9 +108,10 @@ struct MetalContext {
    // State trackers.
    PipelineStateTracker pipelineState;
    DepthStencilStateTracker depthStencilState;
+    std::array<BufferState, Program::UNIFORM_BINDING_COUNT> uniformState;
+    std::array<BufferState, MAX_SSBO_COUNT> ssboState;
    CullModeStateTracker cullModeState;
    WindingStateTracker windingState;
-    DepthClampStateTracker depthClampState;
    Handle<HwRenderPrimitive> currentRenderPrimitive;

    // State caches.
@@ -176,15 +124,13 @@ struct MetalContext {

    std::array<MetalPushConstantBuffer, Program::SHADER_TYPE_COUNT> currentPushConstants;

-    // Keeps track of descriptor sets we've finalized for the current render pass.
-    tsl::robin_set<MetalDescriptorSet*> finalizedDescriptorSets;
-    std::array<MetalDescriptorSet*, MAX_DESCRIPTOR_SET_COUNT> currentDescriptorSets = {};
-    MetalBufferBindings<MAX_DESCRIPTOR_SET_COUNT, ShaderStage::VERTEX> vertexDescriptorBindings;
-    MetalBufferBindings<MAX_DESCRIPTOR_SET_COUNT, ShaderStage::FRAGMENT> fragmentDescriptorBindings;
-    MetalBufferBindings<MAX_DESCRIPTOR_SET_COUNT, ShaderStage::COMPUTE> computeDescriptorBindings;
-    MetalDynamicOffsets dynamicOffsets;
+    MetalSamplerGroup* samplerBindings[Program::SAMPLER_BINDING_COUNT] = {};

-    // Keeps track of all alive textures.
+    // Keeps track of sampler groups we've finalized for the current render pass.
+    tsl::robin_set<MetalSamplerGroup*> finalizedSamplerGroups;
+
+    // Keeps track of all alive sampler groups, textures.
+    tsl::robin_set<MetalSamplerGroup*> samplerGroups;
    tsl::robin_set<MetalTexture*> textures;

    // This circular buffer implements delayed destruction for Metal texture handles. It keeps a
@@ -207,7 +153,6 @@ struct MetalContext {

    // Empty texture used to prevent GPU errors when a sampler has been bound without a texture.
    id<MTLTexture> emptyTexture = nil;
-    id<MTLBuffer> emptyBuffer = nil;

    MetalBlitter* blitter = nullptr;

--- a/filament/backend/src/metal/MetalContext.mm
+++ b/filament/backend/src/metal/MetalContext.mm
@@ -101,14 +101,9 @@ id<MTLCommandBuffer> getPendingCommandBuffer(MetalContext* context) {
    context->pendingCommandBuffer = [context->commandQueue commandBuffer];
    // It's safe for this block to capture the context variable. MetalDriver::terminate will ensure
    // all frames and their completion handlers finish before context is deallocated.
-    uint64_t thisCommandBufferId = context->pendingCommandBufferId;
    [context->pendingCommandBuffer addCompletedHandler:^(id <MTLCommandBuffer> buffer) {
        context->resourceTracker.clearResources((__bridge void*) buffer);
-
-        // Command buffers should complete in order, so latestCompletedCommandBufferId will only
-        // ever increase.
-        context->latestCompletedCommandBufferId = thisCommandBufferId;
-
+        
        auto errorCode = (MTLCommandBufferError)buffer.error.code;
        if (@available(macOS 11.0, *)) {
            if (errorCode == MTLCommandBufferErrorMemoryless) {
@@ -130,7 +125,6 @@ void submitPendingCommands(MetalContext* context) {
    assert_invariant(context->pendingCommandBuffer.status != MTLCommandBufferStatusCommitted);
    [context->pendingCommandBuffer commit];
    context->pendingCommandBuffer = nil;
-    context->pendingCommandBufferId++;
 }

 id<MTLTexture> getOrCreateEmptyTexture(MetalContext* context) {
@@ -173,6 +167,7 @@ void MetalPushConstantBuffer::setPushConstant(PushConstantVariant value, uint8_t

 void MetalPushConstantBuffer::setBytes(id<MTLCommandEncoder> encoder, ShaderStage stage) {
    constexpr size_t PUSH_CONSTANT_SIZE_BYTES = 4;
+    constexpr size_t PUSH_CONSTANT_BUFFER_INDEX = 26;

    static char buffer[MAX_PUSH_CONSTANT_COUNT * PUSH_CONSTANT_SIZE_BYTES];
    assert_invariant(mPushConstants.size() <= MAX_PUSH_CONSTANT_COUNT);
--- a/filament/backend/src/metal/MetalDriver.h
+++ b/filament/backend/src/metal/MetalDriver.h
@@ -32,7 +32,6 @@
 #include <functional>
 #include <mutex>
 #include <vector>
-#include <deque>

 namespace filament {
 namespace backend {
@@ -58,11 +57,11 @@ class MetalDriver final : public DriverBase {

 public:
    static Driver* create(MetalPlatform* platform, const Platform::DriverConfig& driverConfig);
+    void runAtNextTick(const std::function<void()>& fn) noexcept;

 private:

    friend class MetalSwapChain;
-    friend struct MetalDescriptorSet;

    MetalPlatform& mPlatform;
    MetalContext* mContext;
@@ -74,23 +73,10 @@ private:

    /*
     * Tasks run regularly on the driver thread.
-     * Not thread-safe; tasks are run from the driver thead and must be enqueued from the driver
-     * thread.
     */
-    void runAtNextTick(const std::function<void()>& fn) noexcept;
    void executeTickOps() noexcept;
    std::vector<std::function<void()>> mTickOps;
-
-    // Tasks regularly executed on the driver thread after a command buffer has completed
-    struct DeferredTask {
-        DeferredTask(uint64_t commandBufferId, utils::Invocable<void()>&& fn) noexcept
-            : commandBufferId(commandBufferId), fn(std::move(fn)) {}
-        uint64_t commandBufferId;     // after this command buffer completes
-        utils::Invocable<void()> fn;  // execute this task
-    };
-    void executeAfterCurrentCommandBufferCompletes(utils::Invocable<void()>&& fn) noexcept;
-    void executeDeferredOps() noexcept;
-    std::deque<DeferredTask> mDeferredTasks;
+    std::mutex mTickOpsLock;

    /*
     * Driver interface
@@ -151,6 +137,7 @@ private:
    inline void setRenderPrimitiveBuffer(Handle<HwRenderPrimitive> rph, PrimitiveType pt,
            Handle<HwVertexBuffer> vbh, Handle<HwIndexBuffer> ibh);

+    void finalizeSamplerGroup(MetalSamplerGroup* sg);
    void enumerateBoundBuffers(BufferObjectBinding bindingType,
            const std::function<void(const BufferState&, MetalBuffer*, uint32_t)>& f);

--- a/filament/backend/src/metal/MetalDriver.mm
+++ b/filament/backend/src/metal/MetalDriver.mm
--- a/filament/backend/src/metal/MetalExternalImage.h
+++ b/filament/backend/src/metal/MetalExternalImage.h
@@ -32,75 +32,100 @@ struct MetalContext;
 * texture.
 */
 class MetalExternalImage {
+
 public:
-    MetalExternalImage() = default;

-    MetalExternalImage(MetalExternalImage&&);
-    MetalExternalImage& operator=(MetalExternalImage&&);
-    ~MetalExternalImage() noexcept;
-
-    MetalExternalImage(const MetalExternalImage&) = delete;
-    MetalExternalImage& operator=(const MetalExternalImage&) = delete;
+    MetalExternalImage(MetalContext& context,
+            TextureSwizzle r = TextureSwizzle::CHANNEL_0,
+            TextureSwizzle g = TextureSwizzle::CHANNEL_1,
+            TextureSwizzle b = TextureSwizzle::CHANNEL_2,
+            TextureSwizzle a = TextureSwizzle::CHANNEL_3) noexcept;

    /**
-     * While the texture is used for rendering, this MetalExternalImage must be kept alive.
+     * @return true, if this MetalExternalImage is holding a live external image. Returns false
+     * until set has been called with a valid CVPixelBuffer. The image can be cleared via
+     * set(nullptr), and isValid will return false again.
     */
-    id<MTLTexture> getMtlTexture() const noexcept;
-
-    bool isValid() const noexcept {
-        return mImage != nil || mRgbTexture != nullptr;
-    }
-
-    NSUInteger getWidth() const noexcept;
-    NSUInteger getHeight() const noexcept;
+    bool isValid() const noexcept;

    /**
-     * Create an external image with the passed-in CVPixelBuffer.
+     * Set this external image to the passed-in CVPixelBuffer. Future calls to
+     * getMetalTextureForDraw will return a texture backed by this CVPixelBuffer. Previous
+     * CVPixelBuffers and related resources will be released when all GPU work using them has
+     * finished.
     *
-     * Ownership is taken of the CVPixelBuffer, which will be released when the returned
-     * MetalExternalImage is destroyed (or, in the case of a YCbCr image, after the conversion has
-     * completed).
-     *
-     * Calling set with a YCbCr image will encode a compute pass to convert the image from
-     * YCbCr to RGB.
+     * Calling set with a YCbCr image will encode a compute pass to convert the image from YCbCr to
+     * RGB.
     */
-    static MetalExternalImage createFromImage(MetalContext& context, CVPixelBufferRef image);
+    void set(CVPixelBufferRef image) noexcept;

    /**
-     * Create an external image with a specific plane of the passed-in CVPixelBuffer.
-     *
-     * Ownership is taken of the CVPixelBuffer, which will be released when the returned
-     * MetalExternalImage is destroyed.
+     * Set this external image to a specific plane of the passed-in CVPixelBuffer. Future calls to
+     * getMetalTextureForDraw will return a texture backed by a single plane of this CVPixelBuffer.
+     * Previous CVPixelBuffers and related resources will be released when all GPU work using them
+     * has finished.
     */
-    static MetalExternalImage createFromImagePlane(
-            MetalContext& context, CVPixelBufferRef image, uint32_t plane);
+    void set(CVPixelBufferRef image, size_t plane) noexcept;

-    static void assertWritableImage(CVPixelBufferRef image);
+    /**
+     * Returns the width of the external image, or 0 if one is not set. For YCbCr images, returns
+     * the width of the luminance plane.
+     */
+    size_t getWidth() const noexcept { return mWidth; }
+
+    /**
+     * Returns the height of the external image, or 0 if one is not set. For YCbCr images, returns
+     * the height of the luminance plane.
+     */
+    size_t getHeight() const noexcept { return mHeight; }
+
+    /**
+     * Get a Metal texture used to draw this image and denote that it is used for the current frame.
+     * For future frames that use this external image, getMetalTextureForDraw must be called again.
+     */
+    id<MTLTexture> getMetalTextureForDraw() const noexcept;

    /**
     * Free resources. Should be called at least once when no further calls to set will occur.
     */
    static void shutdown(MetalContext& context) noexcept;

-private:
-    MetalExternalImage(CVPixelBufferRef image, CVMetalTextureRef texture) noexcept
-        : mImage(image), mTexture(texture) {}
-    explicit MetalExternalImage(id<MTLTexture> texture) noexcept : mRgbTexture(texture) {}
+    static void assertWritableImage(CVPixelBufferRef image);

-    static id<MTLTexture> createRgbTexture(id<MTLDevice> device, size_t width, size_t height);
-    static CVMetalTextureRef createTextureFromImage(CVMetalTextureCacheRef textureCache,
-            CVPixelBufferRef image, MTLPixelFormat format, size_t plane);
-    static void ensureComputePipelineState(MetalContext& context);
-    static id<MTLCommandBuffer> encodeColorConversionPass(MetalContext& context,
-            id<MTLTexture> inYPlane, id<MTLTexture> inCbCrTexture, id<MTLTexture> outTexture);
+private:
+
+    void unset();
+
+    CVMetalTextureRef createTextureFromImage(CVPixelBufferRef image, MTLPixelFormat format,
+            size_t plane);
+    id<MTLTexture> createRgbTexture(size_t width, size_t height);
+    id<MTLTexture> createSwizzledTextureView(id<MTLTexture> texture) const;
+    id<MTLTexture> createSwizzledTextureView(CVMetalTextureRef texture) const;
+    void ensureComputePipelineState();
+    id<MTLCommandBuffer> encodeColorConversionPass(id<MTLTexture> inYPlane, id<MTLTexture>
+            inCbCrTexture, id<MTLTexture> outTexture);

    static constexpr size_t Y_PLANE = 0;
    static constexpr size_t CBCR_PLANE = 1;

-    // TODO: this could probably be a union.
+    MetalContext& mContext;
+
+    // If the external image has a single plane, mImage and mTexture hold references to the image
+    // and created Metal texture, respectively.
+    // mTextureView is a view of mTexture with any swizzling applied.
    CVPixelBufferRef mImage = nullptr;
    CVMetalTextureRef mTexture = nullptr;
+    id<MTLTexture> mTextureView = nullptr;
+    size_t mWidth = 0;
+    size_t mHeight = 0;
+
+    // If the external image is in the YCbCr format, this holds the result of the converted RGB
+    // texture.
    id<MTLTexture> mRgbTexture = nil;
+
+    struct {
+        TextureSwizzle r, g, b, a;
+    } mSwizzle;
 };

 } // namespace backend
--- a/filament/backend/src/metal/MetalExternalImage.mm
+++ b/filament/backend/src/metal/MetalExternalImage.mm
@@ -34,6 +34,10 @@
 namespace filament {
 namespace backend {

+static const auto cvBufferDeleter = [](const void* buffer) {
+    CVBufferRelease((CVMetalTextureRef) buffer);
+};
+
 static const char* kernel = R"(
 #include <metal_stdlib>
 #include <simd/simd.h>
@@ -67,30 +71,18 @@ ycbcrToRgb(texture2d<half, access::read>  inYTexture    [[texture(0)]],
 }
 )";

-NSUInteger MetalExternalImage::getWidth() const noexcept {
-    if (mImage) {
-        return CVPixelBufferGetWidth(mImage);
-    }
-    if (mRgbTexture) {
-        return mRgbTexture.width;
-    }
-    return 0;
+MetalExternalImage::MetalExternalImage(MetalContext& context, TextureSwizzle r, TextureSwizzle g,
+        TextureSwizzle b, TextureSwizzle a) noexcept : mContext(context), mSwizzle{r, g, b, a} { }
+
+bool MetalExternalImage::isValid() const noexcept {
+    return mRgbTexture != nil || mImage != nullptr;
 }

-NSUInteger MetalExternalImage::getHeight() const noexcept {
-    if (mImage) {
-        return CVPixelBufferGetHeight(mImage);
-    }
-    if (mRgbTexture) {
-        return mRgbTexture.height;
-    }
-    return 0;
-}
+void MetalExternalImage::set(CVPixelBufferRef image) noexcept {
+    unset();

-MetalExternalImage MetalExternalImage::createFromImage(
-        MetalContext& context, CVPixelBufferRef image) {
    if (!image) {
-        return {};
+        return;
    }

    OSType formatType = CVPixelBufferGetPixelFormatType(image);
@@ -104,29 +96,30 @@ MetalExternalImage MetalExternalImage::createFromImage(
            << ".";

    if (planeCount == 0) {
-        CVMetalTextureRef texture =
-                createTextureFromImage(context.textureCache, image, MTLPixelFormatBGRA8Unorm, 0);
-        return { CVPixelBufferRetain(image), texture };
+        mImage = image;
+        mTexture = createTextureFromImage(image, MTLPixelFormatBGRA8Unorm, 0);
+        mTextureView = createSwizzledTextureView(mTexture);
+        mWidth = CVPixelBufferGetWidth(image);
+        mHeight = CVPixelBufferGetHeight(image);
    }

    if (planeCount == 2) {
-        CVPixelBufferRetain(image);
-
-        CVMetalTextureRef yPlane =
-                createTextureFromImage(context.textureCache, image, MTLPixelFormatR8Unorm, Y_PLANE);
-        CVMetalTextureRef cbcrPlane =
-                createTextureFromImage(context.textureCache, image, MTLPixelFormatRG8Unorm, CBCR_PLANE);
+        CVMetalTextureRef yPlane = createTextureFromImage(image, MTLPixelFormatR8Unorm, Y_PLANE);
+        CVMetalTextureRef cbcrPlane = createTextureFromImage(image, MTLPixelFormatRG8Unorm,
+                CBCR_PLANE);

        // Get the size of luminance plane.
-        NSUInteger width = CVPixelBufferGetWidthOfPlane(image, Y_PLANE);
-        NSUInteger height = CVPixelBufferGetHeightOfPlane(image, Y_PLANE);
+        mWidth = CVPixelBufferGetWidthOfPlane(image, Y_PLANE);
+        mHeight = CVPixelBufferGetHeightOfPlane(image, Y_PLANE);

-        id<MTLTexture> rgbTexture = createRgbTexture(context.device, width, height);
-        id<MTLCommandBuffer> commandBuffer = encodeColorConversionPass(context,
+        id<MTLTexture> rgbTexture = createRgbTexture(mWidth, mHeight);
+        id<MTLCommandBuffer> commandBuffer = encodeColorConversionPass(
                CVMetalTextureGetTexture(yPlane),
                CVMetalTextureGetTexture(cbcrPlane),
                rgbTexture);

+        mRgbTexture = createSwizzledTextureView(rgbTexture);
+
        [commandBuffer addCompletedHandler:^(id <MTLCommandBuffer> o) {
            CVBufferRelease(yPlane);
            CVBufferRelease(cbcrPlane);
@@ -134,83 +127,70 @@ MetalExternalImage MetalExternalImage::createFromImage(
        }];

        [commandBuffer commit];
-        return MetalExternalImage { rgbTexture };
    }
-
-    return {};
 }

-MetalExternalImage MetalExternalImage::createFromImagePlane(
-        MetalContext& context, CVPixelBufferRef image, uint32_t plane) {
+void MetalExternalImage::set(CVPixelBufferRef image, size_t plane) noexcept {
+    unset();
+
    if (!image) {
-        return {};
+        return;
    }

    const OSType formatType = CVPixelBufferGetPixelFormatType(image);
    FILAMENT_CHECK_POSTCONDITION(formatType == kCVPixelFormatType_420YpCbCr8BiPlanarFullRange)
            << "Metal planar external images must be in the 420f format.";
-    FILAMENT_CHECK_POSTCONDITION(plane == 0 || plane == 1)
-            << "Metal planar external images must be created from planes 0 or 1.";

-    auto getPlaneFormat = [](size_t plane) {
-        // Right now Metal only supports kCVPixelFormatType_420YpCbCr8BiPlanarFullRange planar
-        // external images, so we can make the following assumptions about the format of each plane.
-        if (plane == 0) {
-            return MTLPixelFormatR8Unorm;  // luminance
-        }
-        if (plane == 1) {
-            return MTLPixelFormatRG8Unorm;  // CbCr
-        }
-        return MTLPixelFormatInvalid;
+    mImage = image;
+
+    auto getPlaneFormat = [] (size_t plane) {
+      // Right now Metal only supports kCVPixelFormatType_420YpCbCr8BiPlanarFullRange planar
+      // external images, so we can make the following assumptions about the format of each plane.
+      if (plane == 0) {
+        return MTLPixelFormatR8Unorm; // luminance
+      }
+      if (plane == 1) {
+        // CbCr
+        return MTLPixelFormatRG8Unorm; // CbCr
+      }
+      return MTLPixelFormatInvalid;
    };

    const MTLPixelFormat format = getPlaneFormat(plane);
    assert_invariant(format != MTLPixelFormatInvalid);
-    CVMetalTextureRef mTexture = createTextureFromImage(context.textureCache, image, format, plane);
-    return { CVPixelBufferRetain(image), mTexture };
+    mTexture = createTextureFromImage(image, format, plane);
+    mTextureView = createSwizzledTextureView(mTexture);
 }

-MetalExternalImage::MetalExternalImage(MetalExternalImage&& rhs) {
-    std::swap(mImage, rhs.mImage);
-    std::swap(mTexture, rhs.mTexture);
-    std::swap(mRgbTexture, rhs.mRgbTexture);
-}
-
-MetalExternalImage& MetalExternalImage::operator=(MetalExternalImage&& rhs) {
-    CVPixelBufferRelease(mImage);
-    CVBufferRelease(mTexture);
-    mImage = nullptr;
-    mTexture = nullptr;
-    mRgbTexture = nullptr;
-    std::swap(mImage, rhs.mImage);
-    std::swap(mTexture, rhs.mTexture);
-    std::swap(mRgbTexture, rhs.mRgbTexture);
-    return *this;
-}
-
-MetalExternalImage::~MetalExternalImage() noexcept {
-    CVPixelBufferRelease(mImage);
-    CVBufferRelease(mTexture);
-}
-
-id<MTLTexture> MetalExternalImage::getMtlTexture() const noexcept {
+id<MTLTexture> MetalExternalImage::getMetalTextureForDraw() const noexcept {
    if (mRgbTexture) {
        return mRgbTexture;
    }
-    if (mTexture) {
-        return CVMetalTextureGetTexture(mTexture);
+
+    // Retain the image and Metal texture until the GPU has finished with this frame. This does
+    // not need to be done for the RGB texture, because it is an Objective-C object whose
+    // lifetime is automatically managed by Metal.
+    auto& tracker = mContext.resourceTracker;
+    auto commandBuffer = getPendingCommandBuffer(&mContext);
+    if (tracker.trackResource((__bridge void*) commandBuffer, mImage, cvBufferDeleter)) {
+        CVPixelBufferRetain(mImage);
    }
-    return nil;
+    if (tracker.trackResource((__bridge void*) commandBuffer, mTexture, cvBufferDeleter)) {
+        CVBufferRetain(mTexture);
+    }
+
+    assert_invariant(mTextureView);
+    return mTextureView;
 }

-CVMetalTextureRef MetalExternalImage::createTextureFromImage(CVMetalTextureCacheRef textureCache,
-        CVPixelBufferRef image, MTLPixelFormat format, size_t plane) {
+CVMetalTextureRef MetalExternalImage::createTextureFromImage(CVPixelBufferRef image,
+        MTLPixelFormat format, size_t plane) {
    const size_t width = CVPixelBufferGetWidthOfPlane(image, plane);
    const size_t height = CVPixelBufferGetHeightOfPlane(image, plane);

    CVMetalTextureRef texture;
-    CVReturn result = CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault, textureCache,
-            image, nullptr, format, width, height, plane, &texture);
+    CVReturn result = CVMetalTextureCacheCreateTextureFromImage(kCFAllocatorDefault,
+            mContext.textureCache, image, nullptr, format, width, height, plane, &texture);
    FILAMENT_CHECK_POSTCONDITION(result == kCVReturnSuccess)
            << "Could not create a CVMetalTexture from CVPixelBuffer.";

@@ -221,19 +201,58 @@ void MetalExternalImage::shutdown(MetalContext& context) noexcept {
    context.externalImageComputePipelineState = nil;
 }

-id<MTLTexture> MetalExternalImage::createRgbTexture(
-        id<MTLDevice> device, size_t width, size_t height) {
+void MetalExternalImage::assertWritableImage(CVPixelBufferRef image) {
+    OSType formatType = CVPixelBufferGetPixelFormatType(image);
+    FILAMENT_CHECK_PRECONDITION(formatType == kCVPixelFormatType_32BGRA)
+            << "Metal SwapChain images must be in the 32BGRA format.";
+}
+
+void MetalExternalImage::unset() {
+    CVPixelBufferRelease(mImage);
+    CVBufferRelease(mTexture);
+
+    mImage = nullptr;
+    mTexture = nullptr;
+    mTextureView = nil;
+    mRgbTexture = nil;
+    mWidth = 0;
+    mHeight = 0;
+}
+
+id<MTLTexture> MetalExternalImage::createRgbTexture(size_t width, size_t height) {
    MTLTextureDescriptor *descriptor =
            [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatRGBA8Unorm
                                                               width:width
                                                              height:height
                                                           mipmapped:NO];
    descriptor.usage = MTLTextureUsageShaderWrite | MTLTextureUsageShaderRead;
-    return [device newTextureWithDescriptor:descriptor];
+    return [mContext.device newTextureWithDescriptor:descriptor];
 }

-void MetalExternalImage::ensureComputePipelineState(MetalContext& context) {
-    if (context.externalImageComputePipelineState != nil) {
+id<MTLTexture> MetalExternalImage::createSwizzledTextureView(id<MTLTexture> texture) const {
+    const bool isDefaultSwizzle =
+            mSwizzle.r == TextureSwizzle::CHANNEL_0 &&
+            mSwizzle.g == TextureSwizzle::CHANNEL_1 &&
+            mSwizzle.b == TextureSwizzle::CHANNEL_2 &&
+            mSwizzle.a == TextureSwizzle::CHANNEL_3;
+    if (!isDefaultSwizzle && mContext.supportsTextureSwizzling) {
+        // Even though we've already checked supportsTextureSwizzling, we still need to guard these
+        // calls with @availability, otherwise the API usage will generate compiler warnings.
+        if (@available(iOS 13, *)) {
+            texture = createTextureViewWithSwizzle(texture,
+                    getSwizzleChannels(mSwizzle.r, mSwizzle.g, mSwizzle.b, mSwizzle.a));
+        }
+    }
+    return texture;
+}
+
+id<MTLTexture> MetalExternalImage::createSwizzledTextureView(CVMetalTextureRef ref) const {
+    id<MTLTexture> texture = CVMetalTextureGetTexture(ref);
+    return createSwizzledTextureView(texture);
+}
+
+void MetalExternalImage::ensureComputePipelineState() {
+    if (mContext.externalImageComputePipelineState != nil) {
        return;
    }

@@ -241,28 +260,29 @@ void MetalExternalImage::ensureComputePipelineState(MetalContext& context) {

    NSString* objcSource = [NSString stringWithCString:kernel
                                              encoding:NSUTF8StringEncoding];
-    id<MTLLibrary> library = [context.device newLibraryWithSource:objcSource
-                                                          options:nil
-                                                            error:&error];
+    id<MTLLibrary> library = [mContext.device newLibraryWithSource:objcSource
+                                                            options:nil
+                                                              error:&error];
    NSERROR_CHECK("Unable to compile Metal shading library.");

    id<MTLFunction> kernelFunction = [library newFunctionWithName:@"ycbcrToRgb"];

-    context.externalImageComputePipelineState =
-            [context.device newComputePipelineStateWithFunction:kernelFunction error:&error];
+    mContext.externalImageComputePipelineState =
+            [mContext.device newComputePipelineStateWithFunction:kernelFunction
+                                                           error:&error];
    NSERROR_CHECK("Unable to create Metal compute pipeline state.");
 }

-id<MTLCommandBuffer> MetalExternalImage::encodeColorConversionPass(MetalContext& context,
-        id<MTLTexture> inYPlane, id<MTLTexture> inCbCrTexture, id<MTLTexture> outTexture) {
-    ensureComputePipelineState(context);
+id<MTLCommandBuffer> MetalExternalImage::encodeColorConversionPass(id<MTLTexture> inYPlane,
+        id<MTLTexture> inCbCrTexture, id<MTLTexture> outTexture) {
+    ensureComputePipelineState();

-    id<MTLCommandBuffer> commandBuffer = [context.commandQueue commandBuffer];
+    id<MTLCommandBuffer> commandBuffer = [mContext.commandQueue commandBuffer];
    commandBuffer.label = @"YCbCr to RGB conversion";

    id<MTLComputeCommandEncoder> computeEncoder = [commandBuffer computeCommandEncoder];

-    [computeEncoder setComputePipelineState:context.externalImageComputePipelineState];
+    [computeEncoder setComputePipelineState:mContext.externalImageComputePipelineState];
    [computeEncoder setTexture:inYPlane atIndex:0];
    [computeEncoder setTexture:inCbCrTexture atIndex:1];
    [computeEncoder setTexture:outTexture atIndex:2];
@@ -280,11 +300,5 @@ id<MTLCommandBuffer> MetalExternalImage::encodeColorConversionPass(MetalContext&
    return commandBuffer;
 }

-void MetalExternalImage::assertWritableImage(CVPixelBufferRef image) {
-    OSType formatType = CVPixelBufferGetPixelFormatType(image);
-    FILAMENT_CHECK_PRECONDITION(formatType == kCVPixelFormatType_32BGRA)
-            << "Metal SwapChain images must be in the 32BGRA format.";
-}
-
 } // namespace backend
 } // namespace filament
--- a/filament/backend/src/metal/MetalHandles.h
+++ b/filament/backend/src/metal/MetalHandles.h
@@ -44,7 +44,6 @@
 #include <condition_variable>
 #include <memory>
 #include <type_traits>
-#include <vector>

 namespace filament {
 namespace backend {
@@ -85,8 +84,6 @@ public:
    NSUInteger getSurfaceWidth() const;
    NSUInteger getSurfaceHeight() const;

-    bool isPixelBuffer() const { return type == SwapChainType::CVPIXELBUFFERREF; }
-
 private:

    enum class SwapChainType {
@@ -96,6 +93,7 @@ private:
    };
    bool isCaMetalLayer() const { return type == SwapChainType::CAMETALLAYER; }
    bool isHeadless() const { return type == SwapChainType::HEADLESS; }
+    bool isPixelBuffer() const { return type == SwapChainType::CVPIXELBUFFERREF; }

    void scheduleFrameScheduledCallback();
    void scheduleFrameCompletedCallback();
@@ -140,6 +138,12 @@ public:
    void updateBufferUnsynchronized(void* data, size_t size, uint32_t byteOffset);
    MetalBuffer* getBuffer() { return &buffer; }

+    // Tracks which uniform/ssbo buffers this buffer object is bound into.
+    static_assert(Program::UNIFORM_BINDING_COUNT <= 32);
+    static_assert(MAX_SSBO_COUNT <= 32);
+    utils::bitset32 boundUniformBuffers;
+    utils::bitset32 boundSsbos;
+
 private:
    MetalBuffer buffer;
 };
@@ -196,10 +200,12 @@ public:
    MetalProgram(MetalContext& context, Program&& program) noexcept;

    const MetalShaderCompiler::MetalFunctionBundle& getFunctions();
+    const Program::SamplerGroupInfo& getSamplerGroupInfo() { return samplerGroupInfo; }

 private:
    void initialize();

+    Program::SamplerGroupInfo samplerGroupInfo;
    MetalContext& mContext;
    MetalShaderCompiler::MetalFunctionBundle mFunctionBundle;
    MetalShaderCompiler::program_token_t mToken;
@@ -221,42 +227,43 @@ struct PixelBufferShape {
 class MetalTexture : public HwTexture {
 public:
    MetalTexture(MetalContext& context, SamplerType target, uint8_t levels, TextureFormat format,
-            uint8_t samples, uint32_t width, uint32_t height, uint32_t depth,
-            TextureUsage usage) noexcept;
-
-    // constructors for creating texture views
-    MetalTexture(MetalContext& context, MetalTexture const* src, uint8_t baseLevel,
-            uint8_t levelCount) noexcept;
-    MetalTexture(MetalContext& context, MetalTexture const* src, TextureSwizzle r, TextureSwizzle g,
-            TextureSwizzle b, TextureSwizzle a) noexcept;
+            uint8_t samples, uint32_t width, uint32_t height, uint32_t depth, TextureUsage usage,
+            TextureSwizzle r, TextureSwizzle g, TextureSwizzle b, TextureSwizzle a)
+            noexcept;

    // Constructor for importing an id<MTLTexture> outside of Filament.
    MetalTexture(MetalContext& context, SamplerType target, uint8_t levels, TextureFormat format,
            uint8_t samples, uint32_t width, uint32_t height, uint32_t depth, TextureUsage usage,
            id<MTLTexture> texture) noexcept;

-    // Constructors for importing external images.
-    MetalTexture(MetalContext& context, TextureFormat format, uint32_t width, uint32_t height,
-            TextureUsage usage, CVPixelBufferRef image) noexcept;
-    MetalTexture(MetalContext& context, TextureFormat format, uint32_t width, uint32_t height,
-            TextureUsage usage, CVPixelBufferRef image, uint32_t plane) noexcept;
+    ~MetalTexture();

-    // Returns an id<MTLTexture> suitable for reading in a shader, taking into account swizzle.
-    id<MTLTexture> getMtlTextureForRead() const noexcept;
+    // Returns an id<MTLTexture> suitable for reading in a shader, taking into account swizzle and
+    // LOD clamping.
+    id<MTLTexture> getMtlTextureForRead() noexcept;

    // Returns the id<MTLTexture> for attaching to a render pass.
-    id<MTLTexture> getMtlTextureForWrite() const noexcept {
+    id<MTLTexture> getMtlTextureForWrite() noexcept {
        return texture;
    }

-    std::shared_ptr<MetalExternalImage> getExternalImage() const noexcept { return externalImage; }
-
    void loadImage(uint32_t level, MTLRegion region, PixelBufferDescriptor& p) noexcept;
    void generateMipmaps() noexcept;

+    // A texture starts out with none of its mip levels (also referred to as LODs) available for
+    // reading. 4 actions update the range of LODs available:
+    // - calling loadImage
+    // - calling generateMipmaps
+    // - using the texture as a render target attachment
+    // - calling setMinMaxLevels
+    // A texture's available mips are consistent throughout a render pass.
+    void setLodRange(uint16_t minLevel, uint16_t maxLevel);
+    void extendLodRangeTo(uint16_t level);
+
    static MTLPixelFormat decidePixelFormat(MetalContext* context, TextureFormat format);

    MetalContext& context;
+    MetalExternalImage externalImage;

    // A "sidecar" texture used to implement automatic MSAA resolve.
    // This is created by MetalRenderTarget and stored here so it can be used with multiple
@@ -295,16 +302,97 @@ private:

    id<MTLTexture> texture = nil;

-    std::shared_ptr<MetalExternalImage> externalImage;
-
    // If non-nil, a swizzled texture view to use instead of "texture".
    // Filament swizzling only affects texture reads, so this should not be used when the texture is
    // bound as a render target attachment.
    id<MTLTexture> swizzledTextureView = nil;
+    id<MTLTexture> lodTextureView = nil;
+
+    uint16_t minLod = std::numeric_limits<uint16_t>::max();
+    uint16_t maxLod = 0;

    bool terminated = false;
 };

+class MetalSamplerGroup : public HwSamplerGroup {
+public:
+    explicit MetalSamplerGroup(size_t size, utils::FixedSizeString<32> name) noexcept
+        : size(size),
+          debugName(name),
+          textureHandles(size, Handle<HwTexture>()),
+          textures(size, nil),
+          samplers(size, nil) {}
+
+    inline void setTextureHandle(size_t index, Handle<HwTexture> th) {
+        assert_invariant(!finalized);
+        textureHandles[index] = th;
+    }
+
+    // This method is only used for debugging, to ensure all texture handles are alive.
+    const auto& getTextureHandles() const {
+        return textureHandles;
+    }
+
+    // Encode a MTLTexture into this SamplerGroup at the given index.
+    inline void setFinalizedTexture(size_t index, id<MTLTexture> t) {
+        assert_invariant(!finalized);
+        textures[index] = t;
+    }
+
+    // Encode a MTLSamplerState into this SamplerGroup at the given index.
+    inline void setFinalizedSampler(size_t index, id<MTLSamplerState> s) {
+        assert_invariant(!finalized);
+        samplers[index] = s;
+    }
+
+    // A SamplerGroup is "finalized" when all of its textures have been set and is ready for use in
+    // a draw call.
+    // Once a SamplerGroup is finalized, it must be reset or mutated to be written into again.
+    void finalize();
+    bool isFinalized() const noexcept { return finalized; }
+
+    // Both of these methods "unfinalize" a SamplerGroup, allowing it to be updated via calls to
+    // setFinalizedTexture or setFinalizedSampler. The difference is that when reset is called, all
+    // the samplers/textures must be rebound. The MTLArgumentEncoder must be specified, in case
+    // the texture types have changed.
+    // Mutate re-encodes the current set of samplers/textures into the new argument
+    // buffer.
+    void reset(id<MTLCommandBuffer> cmdBuffer, id<MTLArgumentEncoder> e, id<MTLDevice> device);
+    void mutate(id<MTLCommandBuffer> cmdBuffer);
+
+    id<MTLBuffer> getArgumentBuffer() const {
+        assert_invariant(finalized);
+        return argBuffer->getCurrentAllocation().first;
+    }
+
+    NSUInteger getArgumentBufferOffset() const {
+        return argBuffer->getCurrentAllocation().second;
+    }
+
+    inline std::pair<Handle<HwTexture>, id<MTLTexture>> getFinalizedTexture(size_t index) {
+        return {textureHandles[index], textures[index]};
+    }
+
+    // Calls the Metal useResource:usage:stages: method for all the textures in this SamplerGroup.
+    void useResources(id<MTLRenderCommandEncoder> renderPassEncoder);
+
+    size_t size;
+    utils::FixedSizeString<32> debugName;
+
+public:
+
+    // These vectors are kept in sync with one another.
+    utils::FixedCapacityVector<Handle<HwTexture>> textureHandles;
+    utils::FixedCapacityVector<id<MTLTexture>> textures;
+    utils::FixedCapacityVector<id<MTLSamplerState>> samplers;
+
+    id<MTLArgumentEncoder> encoder;
+
+    std::unique_ptr<MetalRingBuffer> argBuffer = nullptr;
+
+    bool finalized = false;
+};
+
 class MetalRenderTarget : public HwRenderTarget {
 public:

@@ -459,61 +547,6 @@ struct MetalTimerQuery : public HwTimerQuery {
    std::shared_ptr<Status> status;
 };

-class MetalDescriptorSetLayout : public HwDescriptorSetLayout {
-public:
-    MetalDescriptorSetLayout(DescriptorSetLayout&& layout) noexcept;
-
-    const auto& getBindings() const noexcept { return mLayout.bindings; }
-
-    size_t getDynamicOffsetCount() const noexcept { return mDynamicOffsetCount; }
-
-    /**
-     * Get an argument encoder for this descriptor set and shader stage.
-     * textureTypes should only include the textures present in the corresponding shader stage.
-     */
-    id<MTLArgumentEncoder> getArgumentEncoder(id<MTLDevice> device, ShaderStage stage,
-            utils::FixedCapacityVector<MTLTextureType> const& textureTypes);
-
-private:
-    id<MTLArgumentEncoder> getArgumentEncoderSlow(id<MTLDevice> device, ShaderStage stage,
-            utils::FixedCapacityVector<MTLTextureType> const& textureTypes);
-
-    DescriptorSetLayout mLayout;
-    size_t mDynamicOffsetCount = 0;
-    std::array<id<MTLArgumentEncoder>, Program::SHADER_TYPE_COUNT> mCachedArgumentEncoder = { nil };
-    std::array<utils::FixedCapacityVector<MTLTextureType>, Program::SHADER_TYPE_COUNT>
-            mCachedTextureTypes;
-};
-
-struct MetalDescriptorSet : public HwDescriptorSet {
-    MetalDescriptorSet(MetalDescriptorSetLayout* layout) noexcept;
-
-    void finalize(MetalDriver* driver);
-
-    id<MTLBuffer> finalizeAndGetBuffer(MetalDriver* driver, ShaderStage stage);
-
-    MetalDescriptorSetLayout* layout;
-
-    struct BufferBinding {
-        id<MTLBuffer> buffer;
-        uint32_t offset;
-        uint32_t size;
-    };
-    struct TextureBinding {
-        id<MTLTexture> texture;
-        SamplerParams sampler;
-    };
-    tsl::robin_map<descriptor_binding_t, BufferBinding> buffers;
-    tsl::robin_map<descriptor_binding_t, TextureBinding> textures;
-
-    std::vector<id<MTLResource>> vertexResources;
-    std::vector<id<MTLResource>> fragmentResources;
-
-    std::vector<std::shared_ptr<MetalExternalImage>> externalImages;
-
-    std::array<id<MTLBuffer>, Program::SHADER_TYPE_COUNT> cachedBuffer = { nil };
-};
-
 } // namespace backend
 } // namespace filament

--- a/filament/backend/src/metal/MetalHandles.mm
+++ b/filament/backend/src/metal/MetalHandles.mm
@@ -74,6 +74,7 @@ MetalSwapChain::MetalSwapChain(MetalContext& context, CAMetalLayer* nativeWindow
      depthStencilFormat(decideDepthStencilFormat(flags)),
      layer(nativeWindow),
      layerDrawableMutex(std::make_shared<std::mutex>()),
+      externalImage(context),
      type(SwapChainType::CAMETALLAYER) {

    if (!(flags & SwapChain::CONFIG_TRANSPARENT) && !nativeWindow.opaque) {
@@ -99,15 +100,17 @@ MetalSwapChain::MetalSwapChain(MetalContext& context, int32_t width, int32_t hei
      depthStencilFormat(decideDepthStencilFormat(flags)),
      headlessWidth(width),
      headlessHeight(height),
+      externalImage(context),
      type(SwapChainType::HEADLESS) {}

 MetalSwapChain::MetalSwapChain(MetalContext& context, CVPixelBufferRef pixelBuffer, uint64_t flags)
    : context(context),
      depthStencilFormat(decideDepthStencilFormat(flags)),
-      externalImage(MetalExternalImage::createFromImage(context, pixelBuffer)),
+      externalImage(context),
      type(SwapChainType::CVPIXELBUFFERREF) {
    assert_invariant(flags & SWAP_CHAIN_CONFIG_APPLE_CVPIXELBUFFER);
    MetalExternalImage::assertWritableImage(pixelBuffer);
+    externalImage.set(pixelBuffer);
    assert_invariant(externalImage.isValid());
 }

@@ -118,6 +121,7 @@ MTLPixelFormat MetalSwapChain::decideDepthStencilFormat(uint64_t flags) {
 }

 MetalSwapChain::~MetalSwapChain() {
+    externalImage.set(nullptr);
 }

 NSUInteger MetalSwapChain::getSurfaceWidth() const {
@@ -167,7 +171,7 @@ id<MTLTexture> MetalSwapChain::acquireDrawable() {
    }

    if (isPixelBuffer()) {
-        return externalImage.getMtlTexture();
+        return externalImage.getMetalTextureForDraw();
    }

    assert_invariant(isCaMetalLayer());
@@ -253,6 +257,10 @@ void MetalSwapChain::present() {
    }
 }

+#ifndef FILAMENT_RELEASE_PRESENT_DRAWABLE_MAIN_THREAD
+#define FILAMENT_RELEASE_PRESENT_DRAWABLE_MAIN_THREAD 1
+#endif
+
 class PresentDrawableData {
 public:
    PresentDrawableData() = delete;
@@ -271,10 +279,14 @@ public:
           [that->mDrawable present];
        }

+#if FILAMENT_RELEASE_PRESENT_DRAWABLE_MAIN_THREAD == 1
        // mDrawable is acquired on the driver thread. Typically, we would release this object on
        // the same thread, but after receiving consistent crash reports from within
        // [CAMetalDrawable dealloc], we suspect this object requires releasing on the main thread.
        dispatch_async(dispatch_get_main_queue(), ^{ cleanupAndDestroy(that); });
+#else
+        that->mDriver->runAtNextTick([that]() { cleanupAndDestroy(that); });
+#endif
    }

 private:
@@ -470,6 +482,11 @@ void MetalRenderPrimitive::setBuffers(MetalVertexBufferInfo const* const vbi,

 MetalProgram::MetalProgram(MetalContext& context, Program&& program) noexcept
    : HwProgram(program.getName()), mContext(context) {
+
+    // Save this program's SamplerGroupInfo, it's used during draw calls to bind sampler groups to
+    // the appropriate stage(s).
+    samplerGroupInfo = program.getSamplerGroupInfo();
+
    mToken = context.shaderCompiler->createProgram(program.getName(), std::move(program));
    assert_invariant(mToken);
 }
@@ -489,9 +506,10 @@ void MetalProgram::initialize() {

 MetalTexture::MetalTexture(MetalContext& context, SamplerType target, uint8_t levels,
        TextureFormat format, uint8_t samples, uint32_t width, uint32_t height, uint32_t depth,
-        TextureUsage usage) noexcept
-    : HwTexture(target, levels, samples, width, height, depth, format, usage), context(context) {
-    assert_invariant(target != SamplerType::SAMPLER_EXTERNAL);
+        TextureUsage usage, TextureSwizzle r, TextureSwizzle g, TextureSwizzle b,
+        TextureSwizzle a) noexcept
+    : HwTexture(target, levels, samples, width, height, depth, format, usage), context(context),
+        externalImage(context, r, g, b, a) {

    devicePixelFormat = decidePixelFormat(&context, format);
    FILAMENT_CHECK_POSTCONDITION(devicePixelFormat != MTLPixelFormatInvalid)
@@ -577,28 +595,16 @@ MetalTexture::MetalTexture(MetalContext& context, SamplerType target, uint8_t le
            << ", levels = " << int(levels) << ", MTLPixelFormat = " << int(devicePixelFormat)
            << ", width = " << width << ", height = " << height << ", depth = " << depth
            << "). Out of memory?";
-}

-MetalTexture::MetalTexture(MetalContext& context, MetalTexture const* src, uint8_t baseLevel,
-        uint8_t levelCount) noexcept
-    : HwTexture(src->target, src->levels, src->samples, src->width, src->height, src->depth,
-              src->format, src->usage),
-      context(context),
-      devicePixelFormat(src->devicePixelFormat),
-      externalImage(src->externalImage) {
-    texture = createTextureViewWithLodRange(
-            src->getMtlTextureForRead(), baseLevel, baseLevel + levelCount - 1);
-}
-
-MetalTexture::MetalTexture(MetalContext& context, MetalTexture const* src, TextureSwizzle r,
-        TextureSwizzle g, TextureSwizzle b, TextureSwizzle a) noexcept
-    : HwTexture(src->target, src->levels, src->samples, src->width, src->height, src->depth,
-              src->format, src->usage),
-      context(context),
-      devicePixelFormat(src->devicePixelFormat),
-      externalImage(src->externalImage) {
-    texture = src->getMtlTextureForRead();
-    if (context.supportsTextureSwizzling) {
+    // If swizzling is set, set up a swizzled texture view that we'll use when sampling this texture.
+    const bool isDefaultSwizzle =
+            r == TextureSwizzle::CHANNEL_0 &&
+            g == TextureSwizzle::CHANNEL_1 &&
+            b == TextureSwizzle::CHANNEL_2 &&
+            a == TextureSwizzle::CHANNEL_3;
+    // If texture is nil, then it must be a SAMPLER_EXTERNAL texture.
+    // Swizzling for external textures is handled inside MetalExternalImage.
+    if (!isDefaultSwizzle && texture && context.supportsTextureSwizzling) {
        // Even though we've already checked context.supportsTextureSwizzling, we still need to
        // guard these calls with @availability, otherwise the API usage will generate compiler
        // warnings.
@@ -612,38 +618,44 @@ MetalTexture::MetalTexture(MetalContext& context, MetalTexture const* src, Textu
 MetalTexture::MetalTexture(MetalContext& context, SamplerType target, uint8_t levels, TextureFormat format,
        uint8_t samples, uint32_t width, uint32_t height, uint32_t depth, TextureUsage usage,
        id<MTLTexture> metalTexture) noexcept
-    : HwTexture(target, levels, samples, width, height, depth, format, usage), context(context) {
+    : HwTexture(target, levels, samples, width, height, depth, format, usage), context(context),
+        externalImage(context) {
    texture = metalTexture;
-}
-
-MetalTexture::MetalTexture(MetalContext& context, TextureFormat format, uint32_t width,
-        uint32_t height, TextureUsage usage, CVPixelBufferRef image) noexcept
-    : HwTexture(SamplerType::SAMPLER_EXTERNAL, 1, 1, width, height, 1, format, usage),
-      context(context),
-      externalImage(std::make_shared<MetalExternalImage>(
-              MetalExternalImage::createFromImage(context, image))) {
-    texture = externalImage->getMtlTexture();
-}
-
-MetalTexture::MetalTexture(MetalContext& context, TextureFormat format, uint32_t width,
-        uint32_t height, TextureUsage usage, CVPixelBufferRef image, uint32_t plane) noexcept
-    : HwTexture(SamplerType::SAMPLER_EXTERNAL, 1, 1, width, height, 1, format, usage),
-      context(context),
-      externalImage(std::make_shared<MetalExternalImage>(
-              MetalExternalImage::createFromImagePlane(context, image, plane))) {
-    texture = externalImage->getMtlTexture();
+    setLodRange(0, levels - 1);
 }

 void MetalTexture::terminate() noexcept {
    texture = nil;
    swizzledTextureView = nil;
+    lodTextureView = nil;
    msaaSidecar = nil;
-    externalImage = nullptr;
+    externalImage.set(nullptr);
    terminated = true;
 }

-id<MTLTexture> MetalTexture::getMtlTextureForRead() const noexcept {
-    return swizzledTextureView ? swizzledTextureView : texture;
+MetalTexture::~MetalTexture() {
+    externalImage.set(nullptr);
+}
+
+id<MTLTexture> MetalTexture::getMtlTextureForRead() noexcept {
+    if (lodTextureView) {
+        return lodTextureView;
+    }
+    // The texture's swizzle remains constant throughout its lifetime, however its LOD range can
+    // change. We'll cache the LOD view, and set lodTextureView to nil if minLod or maxLod is
+    // updated.
+    id<MTLTexture> t = swizzledTextureView ? swizzledTextureView : texture;
+    if (!t) {
+        return nil;
+    }
+    if (UTILS_UNLIKELY(minLod > maxLod)) {
+        // If the texture does not have any available LODs, provide a view of only level 0.
+        // Filament should prevent this from ever occurring.
+        lodTextureView = createTextureViewWithLodRange(t, 0, 0);
+        return lodTextureView;
+    }
+    lodTextureView = createTextureViewWithLodRange(t, minLod, maxLod);
+    return lodTextureView;
 }

 MTLPixelFormat MetalTexture::decidePixelFormat(MetalContext* context, TextureFormat format) {
@@ -762,12 +774,15 @@ void MetalTexture::loadImage(uint32_t level, MTLRegion region, PixelBufferDescri
            assert_invariant(false);
        }
    }
+
+    extendLodRangeTo(level);
 }

 void MetalTexture::generateMipmaps() noexcept {
    id <MTLBlitCommandEncoder> blitEncoder = [getPendingCommandBuffer(&context) blitCommandEncoder];
    [blitEncoder generateMipmapsForTexture:texture];
    [blitEncoder endEncoding];
+    setLodRange(0, texture.mipmapLevelCount - 1);
 }

 void MetalTexture::loadSlice(uint32_t level, MTLRegion region, uint32_t byteOffset, uint32_t slice,
@@ -891,6 +906,98 @@ void MetalTexture::loadWithBlit(uint32_t level, uint32_t slice, MTLRegion region
    context.blitter->blit(getPendingCommandBuffer(&context), args, "Texture upload blit");
 }

+void MetalTexture::extendLodRangeTo(uint16_t level) {
+    assert_invariant(!isInRenderPass(&context));
+    minLod = std::min(minLod, level);
+    maxLod = std::max(maxLod, level);
+    lodTextureView = nil;
+}
+
+void MetalTexture::setLodRange(uint16_t min, uint16_t max) {
+    assert_invariant(!isInRenderPass(&context));
+    assert_invariant(min <= max);
+    minLod = min;
+    maxLod = max;
+    lodTextureView = nil;
+}
+
+void MetalSamplerGroup::finalize() {
+    assert_invariant(encoder);
+    // TODO: we should be able to encode textures and samplers inside setFinalizedTexture and
+    // setFinalizedSampler as they become available, but Metal doesn't seem to like this; the arg
+    // buffer gets encoded incorrectly. This warrants more investigation.
+
+    auto [buffer, offset] = argBuffer->getCurrentAllocation();
+    [encoder setArgumentBuffer:buffer offset:offset];
+
+    // Encode all textures and samplers.
+    for (size_t s = 0; s < size; s++) {
+        [encoder setTexture:textures[s] atIndex:(s * 2 + 0)];
+        [encoder setSamplerState:samplers[s] atIndex:(s * 2 + 1)];
+    }
+
+    finalized = true;
+}
+
+void MetalSamplerGroup::reset(id<MTLCommandBuffer> cmdBuffer, id<MTLArgumentEncoder> e,
+        id<MTLDevice> device) {
+    encoder = e;
+
+    // The number of slots in the ring buffer we use to manage argument buffer allocations.
+    // This number was chosen to avoid running out of slots and having to allocate a "fallback"
+    // buffer when SamplerGroups are updated multiple times a frame. This value can reduced after
+    // auditing Filament's calls to updateSamplerGroup, which should be as few times as possible.
+    // For example, the bloom downsample pass should be refactored to maintain two separate
+    // MaterialInstances instead of "ping ponging" between two texture bindings, which causes a
+    // single SamplerGroup to be updated many times a frame.
+    static constexpr auto METAL_ARGUMENT_BUFFER_SLOTS = 32;
+
+    MTLSizeAndAlign argBufferLayout;
+    argBufferLayout.size = encoder.encodedLength;
+    argBufferLayout.align = encoder.alignment;
+    // Chances are, even though the MTLArgumentEncoder might change, the required size and alignment
+    // probably won't. So we can re-use the previous ring buffer.
+    if (UTILS_UNLIKELY(!argBuffer || !argBuffer->canAccomodateLayout(argBufferLayout))) {
+        argBuffer = std::make_unique<MetalRingBuffer>(device, MTLResourceStorageModeShared,
+                argBufferLayout, METAL_ARGUMENT_BUFFER_SLOTS);
+    } else {
+        argBuffer->createNewAllocation(cmdBuffer);
+    }
+
+    // Clear all textures and samplers.
+    assert_invariant(textureHandles.size() == textures.size());
+    assert_invariant(textures.size() == samplers.size());
+    for (size_t s = 0; s < textureHandles.size(); s++) {
+        textureHandles[s] = {};
+        textures[s] = nil;
+        samplers[s] = nil;
+    }
+
+    finalized = false;
+}
+
+void MetalSamplerGroup::mutate(id<MTLCommandBuffer> cmdBuffer) {
+    assert_invariant(finalized);    // only makes sense to mutate if this sampler group is finalized
+    assert_invariant(argBuffer);
+    argBuffer->createNewAllocation(cmdBuffer);
+    finalized = false;
+}
+
+void MetalSamplerGroup::useResources(id<MTLRenderCommandEncoder> renderPassEncoder) {
+    assert_invariant(finalized);
+    if (@available(iOS 13, *)) {
+        // TODO: pass only the appropriate stages to useResources.
+        [renderPassEncoder useResources:textures.data()
+                                  count:textures.size()
+                                  usage:MTLResourceUsageRead | MTLResourceUsageSample
+                                 stages:MTLRenderStageFragment | MTLRenderStageVertex];
+    } else {
+        [renderPassEncoder useResources:textures.data()
+                                  count:textures.size()
+                                  usage:MTLResourceUsageRead | MTLResourceUsageSample];
+    }
+}
+
 MetalRenderTarget::MetalRenderTarget(MetalContext* context, uint32_t width, uint32_t height,
        uint8_t samples, Attachment colorAttachments[MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT],
        Attachment depthAttachment, Attachment stencilAttachment) :
@@ -1236,189 +1343,5 @@ FenceStatus MetalFence::wait(uint64_t timeoutNs) {
    return FenceStatus::ERROR;
 }

-MetalDescriptorSetLayout::MetalDescriptorSetLayout(DescriptorSetLayout&& l) noexcept
-    : mLayout(std::move(l)) {
-    size_t dynamicBindings = 0;
-    for (const auto& binding : mLayout.bindings) {
-        if (any(binding.flags & DescriptorFlags::DYNAMIC_OFFSET)) {
-            dynamicBindings++;
-        }
-    }
-    mDynamicOffsetCount = dynamicBindings;
-}
-
-id<MTLArgumentEncoder> MetalDescriptorSetLayout::getArgumentEncoder(id<MTLDevice> device, ShaderStage stage,
-        utils::FixedCapacityVector<MTLTextureType> const& textureTypes) {
-    auto const index = static_cast<size_t>(stage);
-    assert_invariant(index < mCachedArgumentEncoder.size());
-    if (mCachedArgumentEncoder[index] &&
-            std::equal(
-                    textureTypes.begin(), textureTypes.end(), mCachedTextureTypes[index].begin())) {
-        return mCachedArgumentEncoder[index];
-    }
-    mCachedArgumentEncoder[index] = getArgumentEncoderSlow(device, stage, textureTypes);
-    mCachedTextureTypes[index] = textureTypes;
-    return mCachedArgumentEncoder[index];
-}
-
-id<MTLArgumentEncoder> MetalDescriptorSetLayout::getArgumentEncoderSlow(id<MTLDevice> device,
-        ShaderStage stage, utils::FixedCapacityVector<MTLTextureType> const& textureTypes) {
-    auto const& bindings = getBindings();
-    NSMutableArray<MTLArgumentDescriptor*>* arguments = [NSMutableArray new];
-    // Important! The bindings must be sorted by binding number. This has already been done inside
-    // createDescriptorSetLayout.
-    size_t textureIndex = 0;
-    for (auto const& binding : bindings) {
-        if (!hasShaderType(binding.stageFlags, stage)) {
-            continue;
-        }
-        switch (binding.type) {
-            case DescriptorType::UNIFORM_BUFFER:
-            case DescriptorType::SHADER_STORAGE_BUFFER: {
-                MTLArgumentDescriptor* bufferArgument = [MTLArgumentDescriptor argumentDescriptor];
-                bufferArgument.index = binding.binding * 2;
-                bufferArgument.dataType = MTLDataTypePointer;
-                bufferArgument.access = MTLArgumentAccessReadOnly;
-                [arguments addObject:bufferArgument];
-                break;
-            }
-            case DescriptorType::SAMPLER: {
-                MTLArgumentDescriptor* textureArgument = [MTLArgumentDescriptor argumentDescriptor];
-                textureArgument.index = binding.binding * 2;
-                textureArgument.dataType = MTLDataTypeTexture;
-                MTLTextureType textureType = MTLTextureType2D;
-                if (textureIndex < textureTypes.size()) {
-                    textureType = textureTypes[textureIndex++];
-                }
-                textureArgument.textureType = textureType;
-                textureArgument.access = MTLArgumentAccessReadOnly;
-                [arguments addObject:textureArgument];
-
-                MTLArgumentDescriptor* samplerArgument = [MTLArgumentDescriptor argumentDescriptor];
-                samplerArgument.index = binding.binding * 2 + 1;
-                samplerArgument.dataType = MTLDataTypeSampler;
-                textureArgument.access = MTLArgumentAccessReadOnly;
-                [arguments addObject:samplerArgument];
-                break;
-            }
-            case DescriptorType::INPUT_ATTACHMENT:
-                // TODO: support INPUT_ATTACHMENT
-                assert_invariant(false);
-                break;
-        }
-    }
-    return [device newArgumentEncoderWithArguments:arguments];
-}
-
-MetalDescriptorSet::MetalDescriptorSet(MetalDescriptorSetLayout* layout) noexcept
-    : layout(layout) {}
-
-void MetalDescriptorSet::finalize(MetalDriver* driver) {
-    [driver->mContext->currentRenderPassEncoder useResource:driver->mContext->emptyBuffer
-                                                      usage:MTLResourceUsageRead];
-    [driver->mContext->currentRenderPassEncoder
-            useResource:getOrCreateEmptyTexture(driver->mContext)
-                  usage:MTLResourceUsageRead];
-
-    if (@available(iOS 13.0, *)) {
-        [driver->mContext->currentRenderPassEncoder useResources:vertexResources.data()
-                                                           count:vertexResources.size()
-                                                           usage:MTLResourceUsageRead
-                                                          stages:MTLRenderStageVertex];
-        [driver->mContext->currentRenderPassEncoder useResources:fragmentResources.data()
-                                                           count:fragmentResources.size()
-                                                           usage:MTLResourceUsageRead
-                                                          stages:MTLRenderStageFragment];
-    } else {
-        [driver->mContext->currentRenderPassEncoder useResources:vertexResources.data()
-                                                           count:vertexResources.size()
-                                                           usage:MTLResourceUsageRead];
-        [driver->mContext->currentRenderPassEncoder useResources:fragmentResources.data()
-                                                           count:fragmentResources.size()
-                                                           usage:MTLResourceUsageRead];
-    }
-}
-
-id<MTLBuffer> MetalDescriptorSet::finalizeAndGetBuffer(MetalDriver* driver, ShaderStage stage) {
-    auto const index = static_cast<size_t>(stage);
-    assert_invariant(index < cachedBuffer.size());
-    auto& buffer = cachedBuffer[index];
-
-    if (buffer) {
-        return buffer;
-    }
-
-    // Map all the texture bindings to their respective texture types.
-    auto const& bindings = layout->getBindings();
-    auto textureTypes = utils::FixedCapacityVector<MTLTextureType>::with_capacity(bindings.size());
-    for (auto const& binding : bindings) {
-        if (!hasShaderType(binding.stageFlags, stage)) {
-            continue;
-        }
-        MTLTextureType textureType = MTLTextureType2D;
-        if (auto found = textures.find(binding.binding); found != textures.end()) {
-            auto const& textureBinding = textures[binding.binding];
-            textureType = textureBinding.texture.textureType;
-        }
-        textureTypes.push_back(textureType);
-    }
-
-    MetalContext const& context = *driver->mContext;
-
-    id<MTLArgumentEncoder> encoder =
-            layout->getArgumentEncoder(context.device, stage, textureTypes);
-
-    buffer = [context.device newBufferWithLength:encoder.encodedLength
-                                         options:MTLResourceStorageModeShared];
-    [encoder setArgumentBuffer:buffer offset:0];
-
-    for (auto const& binding : bindings) {
-        if (!hasShaderType(binding.stageFlags, stage)) {
-            continue;
-        }
-        switch (binding.type) {
-            case DescriptorType::UNIFORM_BUFFER:
-            case DescriptorType::SHADER_STORAGE_BUFFER: {
-                auto found = buffers.find(binding.binding);
-                if (found == buffers.end()) {
-                    [encoder setBuffer:driver->mContext->emptyBuffer
-                                offset:0
-                               atIndex:binding.binding * 2];
-                    continue;
-                }
-
-                auto const& bufferBinding = buffers[binding.binding];
-                [encoder setBuffer:bufferBinding.buffer
-                            offset:bufferBinding.offset
-                           atIndex:binding.binding * 2];
-                break;
-            }
-            case DescriptorType::SAMPLER: {
-                auto found = textures.find(binding.binding);
-                if (found == textures.end()) {
-                    [encoder setTexture:driver->mContext->emptyTexture atIndex:binding.binding * 2];
-                    id<MTLSamplerState> sampler =
-                            driver->mContext->samplerStateCache.getOrCreateState({});
-                    [encoder setSamplerState:sampler atIndex:binding.binding * 2 + 1];
-                    continue;
-                }
-
-                auto const& textureBinding = textures[binding.binding];
-                [encoder setTexture:textureBinding.texture atIndex:binding.binding * 2];
-                SamplerState samplerState { .samplerParams = textureBinding.sampler };
-                id<MTLSamplerState> sampler =
-                        driver->mContext->samplerStateCache.getOrCreateState(samplerState);
-                [encoder setSamplerState:sampler atIndex:binding.binding * 2 + 1];
-                break;
-            }
-            case DescriptorType::INPUT_ATTACHMENT:
-                assert_invariant(false);
-                break;
-        }
-    }
-
-    return buffer;
-}
-
 } // namespace backend
 } // namespace filament
--- a/filament/backend/src/metal/MetalState.h
+++ b/filament/backend/src/metal/MetalState.h
@@ -33,28 +33,32 @@
 namespace filament {
 namespace backend {

+inline bool operator==(const SamplerParams& lhs, const SamplerParams& rhs) {
+    return SamplerParams::EqualTo{}(lhs, rhs);
+}
+
 //   Rasterization Bindings
 //   ----------------------
 //   Bindings    Buffer name                          Count
 //   ------------------------------------------------------
 //   0           Zero buffer (placeholder vertex buffer)  1
 //   1-16        Filament vertex buffers                 16   limited by MAX_VERTEX_BUFFER_COUNT
-//   20          Push constants                           1
-//   21-24       Descriptor sets (argument buffers)       4   limited by MAX_DESCRIPTOR_SET_COUNT
-//   25          Dynamic offset buffer                    1
+//   17-25       Uniform buffers                          9   Program::UNIFORM_BINDING_COUNT
+//   26          Push constants                           1
+//   27-30       Sampler groups (argument buffers)        4   Program::SAMPLER_BINDING_COUNT
 //
-//   Total                                               23
+//   Total                                               31

 //   Compute Bindings
 //   ----------------------
 //   Bindings    Buffer name                          Count
 //   ------------------------------------------------------
 //   0-3         SSBO buffers                             4   MAX_SSBO_COUNT
-//   20          Push constants                           1
-//   21-24       Descriptor sets (argument buffers)       4   limited by MAX_DESCRIPTOR_SET_COUNT
-//   25          Dynamic offset buffer                    1
+//   17-25       Uniform buffers                          9   Program::UNIFORM_BINDING_COUNT
+//   26          Push constants                           1
+//   27-30       Sampler groups (argument buffers)        4   Program::SAMPLER_BINDING_COUNT
 //
-//   Total                                               10
+//   Total                                               18

 // The total number of vertex buffer "slots" that the Metal backend can bind.
 // + 1 to account for the zero buffer, a placeholder buffer used internally by the Metal backend.
@@ -67,11 +71,10 @@ static constexpr uint32_t ZERO_VERTEX_BUFFER_BINDING = 0u;

 static constexpr uint32_t USER_VERTEX_BUFFER_BINDING_START = 1u;

-
 // These constants must match the equivalent in CodeGenerator.h.
-static constexpr uint32_t PUSH_CONSTANT_BUFFER_INDEX = 20u;
-static constexpr uint32_t DESCRIPTOR_SET_BINDING_START = 21u;
-static constexpr uint32_t DYNAMIC_OFFSET_BINDING = 25u;
+static constexpr uint32_t UNIFORM_BUFFER_BINDING_START = 17u;
+static constexpr uint32_t SSBO_BINDING_START = 0u;
+static constexpr uint32_t SAMPLER_GROUP_BINDING_START = 27u;

 // Forward declarations necessary here, definitions at end of file.
 inline bool operator==(const MTLViewport& lhs, const MTLViewport& rhs);
@@ -379,22 +382,18 @@ using SamplerStateCache = StateCache<SamplerState, id<MTLSamplerState>, SamplerS

 using CullModeStateTracker = StateTracker<MTLCullMode>;
 using WindingStateTracker = StateTracker<MTLWinding>;
-using DepthClampStateTracker = StateTracker<MTLDepthClipMode>;

 // Argument encoder

 struct ArgumentEncoderState {
-    NSUInteger bufferCount;
    utils::FixedCapacityVector<MTLTextureType> textureTypes;

-    explicit ArgumentEncoderState(
-            NSUInteger bufferCount, utils::FixedCapacityVector<MTLTextureType>&& types)
-        : bufferCount(bufferCount), textureTypes(std::move(types)) {}
+    explicit ArgumentEncoderState(utils::FixedCapacityVector<MTLTextureType>&& types)
+        : textureTypes(std::move(types)) {}

    bool operator==(const ArgumentEncoderState& rhs) const noexcept {
        return std::equal(textureTypes.begin(), textureTypes.end(), rhs.textureTypes.begin(),
-                       rhs.textureTypes.end()) &&
-                bufferCount == rhs.bufferCount;
+                rhs.textureTypes.end());
    }

    bool operator!=(const ArgumentEncoderState& rhs) const noexcept {
@@ -416,30 +415,6 @@ struct ArgumentEncoderCreator {
 using ArgumentEncoderCache = StateCache<ArgumentEncoderState, id<MTLArgumentEncoder>,
        ArgumentEncoderCreator, ArgumentEncoderHasher>;

-template <NSUInteger N, ShaderStage stage>
-class MetalBufferBindings {
-public:
-    MetalBufferBindings() { invalidate(); }
-
-    void invalidate() {
-        mDirtyBuffers.reset();
-        mDirtyOffsets.reset();
-        for (int i = 0; i < int(N); i++) {
-            mDirtyBuffers.set(i, true);
-            mDirtyOffsets.set(i, true);
-        }
-    }
-    void setBuffer(const id<MTLBuffer> buffer, NSUInteger offset, NSUInteger index);
-    void bindBuffers(id<MTLCommandEncoder> encoder, NSUInteger startIndex);
-
-private:
-    static_assert(N <= 8);
-    std::array<__unsafe_unretained id<MTLBuffer>, N> mBuffers = { nil };
-    std::array<NSUInteger, N> mOffsets = { 0 };
-    utils::bitset8 mDirtyBuffers;
-    utils::bitset8 mDirtyOffsets;
-};
-
 } // namespace backend
 } // namespace filament

--- a/filament/backend/src/metal/MetalState.mm
+++ b/filament/backend/src/metal/MetalState.mm
@@ -166,40 +166,28 @@ id<MTLSamplerState> SamplerStateCreator::operator()(id<MTLDevice> device,
 id<MTLArgumentEncoder> ArgumentEncoderCreator::operator()(id<MTLDevice> device,
        const ArgumentEncoderState &state) noexcept {
    const auto& textureTypes = state.textureTypes;
-    const auto& textureCount = textureTypes.size();
-    const auto& bufferCount = state.bufferCount;
-    assert_invariant(textureCount > 0);
+    const auto& count = textureTypes.size();
+    assert_invariant(count > 0);

    // Metal has separate data types for textures versus samplers, so the argument buffer layout
    // alternates between texture and sampler, i.e.:
-    // buffer0
-    // buffer1
    // textureA
    // samplerA
    // textureB
    // samplerB
    // etc
    NSMutableArray<MTLArgumentDescriptor*>* arguments =
-            [NSMutableArray arrayWithCapacity:(bufferCount + textureCount * 2)];
-    size_t i = 0;
-    for (size_t j = 0; j < bufferCount; j++) {
-        MTLArgumentDescriptor* bufferArgument = [MTLArgumentDescriptor argumentDescriptor];
-        bufferArgument.index = i++;
-        bufferArgument.dataType = MTLDataTypePointer;
-        bufferArgument.access = MTLArgumentAccessReadOnly;
-        [arguments addObject:bufferArgument];
-    }
-
-    for (size_t j = 0; j < textureCount; j++) {
+            [NSMutableArray arrayWithCapacity:(count * 2)];
+    for (size_t i = 0; i < count; i++) {
        MTLArgumentDescriptor* textureArgument = [MTLArgumentDescriptor argumentDescriptor];
-        textureArgument.index = i++;
+        textureArgument.index = i * 2 + 0;
        textureArgument.dataType = MTLDataTypeTexture;
        textureArgument.textureType = textureTypes[i];
        textureArgument.access = MTLArgumentAccessReadOnly;
        [arguments addObject:textureArgument];

        MTLArgumentDescriptor* samplerArgument = [MTLArgumentDescriptor argumentDescriptor];
-        samplerArgument.index = i++;
+        samplerArgument.index = i * 2 + 1;
        samplerArgument.dataType = MTLDataTypeSampler;
        textureArgument.access = MTLArgumentAccessReadOnly;
        [arguments addObject:samplerArgument];
@@ -208,64 +196,5 @@ id<MTLArgumentEncoder> ArgumentEncoderCreator::operator()(id<MTLDevice> device,
    return [device newArgumentEncoderWithArguments:arguments];
 }

-template <NSUInteger N, ShaderStage stage>
-void MetalBufferBindings<N, stage>::setBuffer(const id<MTLBuffer> buffer, NSUInteger offset, NSUInteger index) {
-    assert_invariant(offset + 1 <= N);
-
-    if (mBuffers[index] != buffer) {
-        mBuffers[index] = buffer;
-        mDirtyBuffers.set(index);
-    }
-
-    if (mOffsets[index] != offset) {
-        mOffsets[index] = offset;
-        mDirtyOffsets.set(index);
-    }
-}
-
-template <NSUInteger N, ShaderStage stage>
-void MetalBufferBindings<N, stage>::bindBuffers(
-        id<MTLCommandEncoder> encoder, NSUInteger startIndex) {
-    if (mDirtyBuffers.none() && mDirtyOffsets.none()) {
-        return;
-    }
-
-    utils::bitset8 onlyOffsetDirty = mDirtyOffsets & ~mDirtyBuffers;
-    onlyOffsetDirty.forEachSetBit([&](size_t i) {
-        if constexpr (stage == ShaderStage::VERTEX) {
-            [(id<MTLRenderCommandEncoder>)encoder setVertexBufferOffset:mOffsets[i]
-                                                                atIndex:i + startIndex];
-        } else if constexpr (stage == ShaderStage::FRAGMENT) {
-            [(id<MTLRenderCommandEncoder>)encoder setFragmentBufferOffset:mOffsets[i]
-                                                                  atIndex:i + startIndex];
-        } else if constexpr (stage == ShaderStage::COMPUTE) {
-            [(id<MTLComputeCommandEncoder>)encoder setBufferOffset:mOffsets[i]
-                                                           atIndex:i + startIndex];
-        }
-    });
-    mDirtyOffsets.reset();
-
-    mDirtyBuffers.forEachSetBit([&](size_t i) {
-        if constexpr (stage == ShaderStage::VERTEX) {
-            [(id<MTLRenderCommandEncoder>)encoder setVertexBuffer:mBuffers[i]
-                                                           offset:mOffsets[i]
-                                                          atIndex:i + startIndex];
-        } else if constexpr (stage == ShaderStage::FRAGMENT) {
-            [(id<MTLRenderCommandEncoder>)encoder setFragmentBuffer:mBuffers[i]
-                                                             offset:mOffsets[i]
-                                                            atIndex:i + startIndex];
-        } else if constexpr (stage == ShaderStage::COMPUTE) {
-            [(id<MTLComputeCommandEncoder>)encoder setBuffer:mBuffers[i]
-                                                      offset:mOffsets[i]
-                                                     atIndex:i + startIndex];
-        }
-    });
-    mDirtyBuffers.reset();
-}
-
-template class MetalBufferBindings<MAX_DESCRIPTOR_SET_COUNT, ShaderStage::VERTEX>;
-template class MetalBufferBindings<MAX_DESCRIPTOR_SET_COUNT, ShaderStage::FRAGMENT>;
-template class MetalBufferBindings<MAX_DESCRIPTOR_SET_COUNT, ShaderStage::COMPUTE>;
-
 } // namespace backend
 } // namespace filament
--- a/filament/backend/src/noop/NoopDriver.cpp
+++ b/filament/backend/src/noop/NoopDriver.cpp
@@ -99,6 +99,9 @@ void NoopDriver::destroyProgram(Handle<HwProgram> ph) {
 void NoopDriver::destroyRenderTarget(Handle<HwRenderTarget> rth) {
 }

+void NoopDriver::destroySamplerGroup(Handle<HwSamplerGroup> sbh) {
+}
+
 void NoopDriver::destroySwapChain(Handle<HwSwapChain> sch) {
 }

@@ -108,12 +111,6 @@ void NoopDriver::destroyStream(Handle<HwStream> sh) {
 void NoopDriver::destroyTimerQuery(Handle<HwTimerQuery> tqh) {
 }

-void NoopDriver::destroyDescriptorSetLayout(Handle<HwDescriptorSetLayout> tqh) {
-}
-
-void NoopDriver::destroyDescriptorSet(Handle<HwDescriptorSet> tqh) {
-}
-
 Handle<HwStream> NoopDriver::createStreamNative(void* nativeStream) {
    return {};
 }
@@ -205,10 +202,6 @@ bool NoopDriver::isProtectedTexturesSupported() {
    return true;
 }

-bool NoopDriver::isDepthClampSupported() {
-    return false;
-}
-
 bool NoopDriver::isWorkaroundNeeded(Workaround) {
    return false;
 }
@@ -251,6 +244,9 @@ void NoopDriver::setVertexBufferObject(Handle<HwVertexBuffer> vbh, uint32_t inde
        Handle<HwBufferObject> boh) {
 }

+void NoopDriver::setMinMaxLevels(Handle<HwTexture> th, uint32_t minLevel, uint32_t maxLevel) {
+}
+
 void NoopDriver::update3DImage(Handle<HwTexture> th,
        uint32_t level, uint32_t xoffset, uint32_t yoffset, uint32_t zoffset,
        uint32_t width, uint32_t height, uint32_t depth,
@@ -276,6 +272,11 @@ void NoopDriver::setExternalStream(Handle<HwTexture> th, Handle<HwStream> sh) {

 void NoopDriver::generateMipmaps(Handle<HwTexture> th) { }

+void NoopDriver::updateSamplerGroup(Handle<HwSamplerGroup> sbh,
+        BufferDescriptor&& data) {
+    scheduleDestroy(std::move(data));
+}
+
 void NoopDriver::compilePrograms(CompilerPriorityQueue priority,
        CallbackHandler* handler, CallbackHandler::Callback callback, void* user) {
    if (callback) {
@@ -298,14 +299,27 @@ void NoopDriver::makeCurrent(Handle<HwSwapChain> drawSch, Handle<HwSwapChain> re
 void NoopDriver::commit(Handle<HwSwapChain> sch) {
 }

+void NoopDriver::bindUniformBuffer(uint32_t index, Handle<HwBufferObject> ubh) {
+}
+
+void NoopDriver::bindBufferRange(BufferObjectBinding bindingType, uint32_t index,
+        Handle<HwBufferObject> ubh, uint32_t offset, uint32_t size) {
+}
+
+void NoopDriver::unbindBuffer(BufferObjectBinding bindingType, uint32_t index) {
+}
+
+void NoopDriver::bindSamplers(uint32_t index, Handle<HwSamplerGroup> sbh) {
+}
+
 void NoopDriver::setPushConstant(backend::ShaderStage stage, uint8_t index,
        backend::PushConstantVariant value) {
 }

-void NoopDriver::insertEventMarker(char const* string) {
+void NoopDriver::insertEventMarker(char const* string, uint32_t len) {
 }

-void NoopDriver::pushGroupMarker(char const* string) {
+void NoopDriver::pushGroupMarker(char const* string,  uint32_t len) {
 }

 void NoopDriver::popGroupMarker(int) {
@@ -374,28 +388,4 @@ void NoopDriver::endTimerQuery(Handle<HwTimerQuery> tqh) {
 void NoopDriver::resetState(int) {
 }

-void NoopDriver::updateDescriptorSetBuffer(
-        backend::DescriptorSetHandle dsh,
-        backend::descriptor_binding_t binding,
-        backend::BufferObjectHandle boh,
-        uint32_t offset,
-        uint32_t size) {
-}
-
-void NoopDriver::updateDescriptorSetTexture(
-        backend::DescriptorSetHandle dsh,
-        backend::descriptor_binding_t binding,
-        backend::TextureHandle th,
-        SamplerParams params) {
-}
-
-void NoopDriver::bindDescriptorSet(
-        backend::DescriptorSetHandle dsh,
-        backend::descriptor_set_t set,
-        backend::DescriptorSetOffsetArray&& offsets) {
-}
-
-void NoopDriver::setDebugTag(HandleBase::HandleId handleId, utils::CString tag) {
-}
-
 } // namespace filament
--- a/filament/backend/src/opengl/BindingMap.h
+++ b/filament/backend/src/opengl/BindingMap.h
@@ -1,89 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef TNT_FILAMENT_BACKEND_OPENGL_BINDINGMAP_H
-#define TNT_FILAMENT_BACKEND_OPENGL_BINDINGMAP_H
-
-#include <backend/DriverEnums.h>
-
-#include "gl_headers.h"
-
-#include <utils/bitset.h>
-#include <utils/debug.h>
-
-#include <new>
-
-#include <stddef.h>
-#include <stdint.h>
-#include <string.h>
-
-namespace filament::backend {
-
-class BindingMap {
-    struct CompressedBinding {
-        // this is in fact a GLuint, but we only want 8-bits
-        uint8_t binding : 7;
-        uint8_t sampler : 1;
-    };
-
-    CompressedBinding (*mStorage)[MAX_DESCRIPTOR_COUNT];
-
-    utils::bitset64 mActiveDescriptors[MAX_DESCRIPTOR_SET_COUNT];
-
-public:
-    BindingMap() noexcept
-            : mStorage(new (std::nothrow) CompressedBinding[MAX_DESCRIPTOR_SET_COUNT][MAX_DESCRIPTOR_COUNT]) {
-#ifndef NDEBUG
-        memset(mStorage, 0xFF, sizeof(CompressedBinding[MAX_DESCRIPTOR_SET_COUNT][MAX_DESCRIPTOR_COUNT]));
-#endif
-    }
-
-    ~BindingMap() noexcept {
-        delete [] mStorage;
-    }
-
-    BindingMap(BindingMap const&) noexcept = delete;
-    BindingMap(BindingMap&&) noexcept = delete;
-    BindingMap& operator=(BindingMap const&) noexcept = delete;
-    BindingMap& operator=(BindingMap&&) noexcept = delete;
-
-    struct Binding {
-        GLuint binding;
-        DescriptorType type;
-    };
-
-    void insert(descriptor_set_t set, descriptor_binding_t binding, Binding entry) noexcept {
-        assert_invariant(set < MAX_DESCRIPTOR_SET_COUNT);
-        assert_invariant(binding < MAX_DESCRIPTOR_COUNT);
-        assert_invariant(entry.binding < 128); // we reserve 1 bit for the type right now
-        mStorage[set][binding] = { (uint8_t)entry.binding, entry.type == DescriptorType::SAMPLER };
-        mActiveDescriptors[set].set(binding);
-    }
-
-    GLuint get(descriptor_set_t set, descriptor_binding_t binding) const noexcept {
-        assert_invariant(set < MAX_DESCRIPTOR_SET_COUNT);
-        assert_invariant(binding < MAX_DESCRIPTOR_COUNT);
-        return mStorage[set][binding].binding;
-    }
-
-    utils::bitset64 getActiveDescriptors(descriptor_set_t set) const noexcept {
-        return mActiveDescriptors[set];
-    }
-};
-
-} // namespace filament::backend
-
-#endif //TNT_FILAMENT_BACKEND_OPENGL_BINDINGMAP_H
--- a/filament/backend/src/opengl/GLDescriptorSet.cpp
+++ b/filament/backend/src/opengl/GLDescriptorSet.cpp
@@ -1,361 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "GLDescriptorSet.h"
-
-#include "GLBufferObject.h"
-#include "GLDescriptorSetLayout.h"
-#include "GLTexture.h"
-#include "GLUtils.h"
-#include "OpenGLDriver.h"
-#include "OpenGLContext.h"
-#include "OpenGLProgram.h"
-
-#include "gl_headers.h"
-
-#include <private/backend/HandleAllocator.h>
-
-#include <backend/DriverEnums.h>
-#include <backend/Handle.h>
-
-#include <utils/BitmaskEnum.h>
-#include <utils/Log.h>
-#include <utils/Panic.h>
-#include <utils/bitset.h>
-#include <utils/compiler.h>
-#include <utils/debug.h>
-#include <algorithm>
-
-#include <type_traits>
-#include <utility>
-#include <variant>
-
-#include <stddef.h>
-#include <stdint.h>
-
-namespace filament::backend {
-
-GLDescriptorSet::GLDescriptorSet(OpenGLContext& gl, DescriptorSetLayoutHandle dslh,
-        GLDescriptorSetLayout const* layout) noexcept
-        : descriptors(layout->maxDescriptorBinding + 1),
-          dslh(std::move(dslh)) {
-
-    // We have allocated enough storage for all descriptors. Now allocate the empty descriptor
-    // themselves.
-    for (auto const& entry : layout->bindings) {
-        size_t const index = entry.binding;
-
-        // now we'll initialize the alternative for each way we can handle this descriptor.
-        auto& desc = descriptors[index].desc;
-        switch (entry.type) {
-            case DescriptorType::UNIFORM_BUFFER: {
-                // A uniform buffer can have dynamic offsets or not and have special handling for
-                // ES2 (where we need to emulate it). That's four alternatives.
-                bool const dynamicOffset = any(entry.flags & DescriptorFlags::DYNAMIC_OFFSET);
-                dynamicBuffers.set(index, dynamicOffset);
-                if (UTILS_UNLIKELY(gl.isES2())) {
-                    dynamicBufferCount++;
-                    desc.emplace<BufferGLES2>(dynamicOffset);
-                } else {
-                    auto const type = GLUtils::getBufferBindingType(BufferObjectBinding::UNIFORM);
-                    if (dynamicOffset) {
-                        dynamicBufferCount++;
-                        desc.emplace<DynamicBuffer>(type);
-                    } else {
-                        desc.emplace<Buffer>(type);
-                    }
-                }
-                break;
-            }
-            case DescriptorType::SHADER_STORAGE_BUFFER: {
-                // shader storage buffers are not supported on ES2, So that's two alternatives.
-                bool const dynamicOffset = any(entry.flags & DescriptorFlags::DYNAMIC_OFFSET);
-                dynamicBuffers.set(index, dynamicOffset);
-                auto const type = GLUtils::getBufferBindingType(BufferObjectBinding::SHADER_STORAGE);
-                if (dynamicOffset) {
-                    dynamicBufferCount++;
-                    desc.emplace<DynamicBuffer>(type);
-                } else {
-                    desc.emplace<Buffer>(type);
-                }
-                break;
-            }
-            case DescriptorType::SAMPLER:
-                if (UTILS_UNLIKELY(gl.isES2())) {
-                    desc.emplace<SamplerGLES2>();
-                } else {
-                    const bool anisotropyWorkaround =
-                            gl.ext.EXT_texture_filter_anisotropic &&
-                            gl.bugs.texture_filter_anisotropic_broken_on_sampler;
-                    if (anisotropyWorkaround) {
-                        desc.emplace<SamplerWithAnisotropyWorkaround>();
-                    } else {
-                        desc.emplace<Sampler>();
-                    }
-                }
-                break;
-            case DescriptorType::INPUT_ATTACHMENT:
-                break;
-        }
-    }
-}
-
-void GLDescriptorSet::update(OpenGLContext&,
-        descriptor_binding_t binding, GLBufferObject* bo, size_t offset, size_t size) noexcept {
-    assert_invariant(binding < descriptors.size());
-    std::visit([=](auto&& arg) {
-        using T = std::decay_t<decltype(arg)>;
-        if constexpr (std::is_same_v<T, Buffer> || std::is_same_v<T, DynamicBuffer>) {
-            assert_invariant(arg.target != 0);
-            arg.id = bo ? bo->gl.id : 0;
-            arg.offset = uint32_t(offset);
-            arg.size = uint32_t(size);
-            assert_invariant(arg.id || (!arg.size && !offset));
-        } else if constexpr (std::is_same_v<T, BufferGLES2>) {
-            arg.bo = bo;
-            arg.offset = uint32_t(offset);
-        } else {
-            // API usage error. User asked to update the wrong type of descriptor.
-            PANIC_PRECONDITION("descriptor %d is not a buffer", +binding);
-        }
-    }, descriptors[binding].desc);
-}
-
-void GLDescriptorSet::update(OpenGLContext& gl,
-        descriptor_binding_t binding, GLTexture* t, SamplerParams params) noexcept {
-    assert_invariant(binding < descriptors.size());
-    std::visit([=, &gl](auto&& arg) mutable {
-        using T = std::decay_t<decltype(arg)>;
-        if constexpr (std::is_same_v<T, Sampler> ||
-                      std::is_same_v<T, SamplerWithAnisotropyWorkaround> ||
-                      std::is_same_v<T, SamplerGLES2>) {
-            if (UTILS_UNLIKELY(t && t->target == SamplerType::SAMPLER_EXTERNAL)) {
-                // From OES_EGL_image_external spec:
-                // "The default s and t wrap modes are CLAMP_TO_EDGE, and it is an INVALID_ENUM
-                //  error to set the wrap mode to any other value."
-                params.wrapS = SamplerWrapMode::CLAMP_TO_EDGE;
-                params.wrapT = SamplerWrapMode::CLAMP_TO_EDGE;
-                params.wrapR = SamplerWrapMode::CLAMP_TO_EDGE;
-            }
-            // GLES3.x specification forbids depth textures to be filtered.
-            if (t && isDepthFormat(t->format)
-                    && params.compareMode == SamplerCompareMode::NONE) {
-                params.filterMag = SamplerMagFilter::NEAREST;
-                switch (params.filterMin) {
-                    case SamplerMinFilter::LINEAR:
-                        params.filterMin = SamplerMinFilter::NEAREST;
-                        break;
-                    case SamplerMinFilter::LINEAR_MIPMAP_NEAREST:
-                    case SamplerMinFilter::NEAREST_MIPMAP_LINEAR:
-                    case SamplerMinFilter::LINEAR_MIPMAP_LINEAR:
-                        params.filterMin = SamplerMinFilter::NEAREST_MIPMAP_NEAREST;
-                        break;
-                    default:
-                        break;
-                }
-            }
-
-            arg.target = t ? t->gl.target : 0;
-            arg.id = t ? t->gl.id : 0;
-            if constexpr (std::is_same_v<T, Sampler> ||
-                          std::is_same_v<T, SamplerWithAnisotropyWorkaround>) {
-                if constexpr (std::is_same_v<T, SamplerWithAnisotropyWorkaround>) {
-                    arg.anisotropy = float(1u << params.anisotropyLog2);
-                }
-                if (t) {
-                    arg.ref = t->ref;
-                    arg.baseLevel = t->gl.baseLevel;
-                    arg.maxLevel = t->gl.maxLevel;
-                    arg.swizzle = t->gl.swizzle;
-                }
-#ifndef FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2
-                arg.sampler = gl.getSampler(params);
-#else
-                (void)gl;
-#endif
-            } else {
-                arg.params = params;
-            }
-        } else {
-            // API usage error. User asked to update the wrong type of descriptor.
-            PANIC_PRECONDITION("descriptor %d is not a texture", +binding);
-        }
-    }, descriptors[binding].desc);
-}
-
-template<typename T>
-void GLDescriptorSet::updateTextureView(OpenGLContext& gl,
-        HandleAllocatorGL& handleAllocator, GLuint unit, T const& desc) noexcept {
-    // The common case is that we don't have a ref handle (we only have one if
-    // the texture ever had a View on it).
-    assert_invariant(desc.ref);
-    GLTextureRef* const ref = handleAllocator.handle_cast<GLTextureRef*>(desc.ref);
-    if (UTILS_UNLIKELY((desc.baseLevel != ref->baseLevel || desc.maxLevel != ref->maxLevel))) {
-        // If we have views, then it's still uncommon that we'll switch often
-        // handle the case where we reset to the original texture
-        GLint baseLevel = GLint(desc.baseLevel); // NOLINT(*-signed-char-misuse)
-        GLint maxLevel = GLint(desc.maxLevel); // NOLINT(*-signed-char-misuse)
-        if (baseLevel > maxLevel) {
-            baseLevel = 0;
-            maxLevel = 1000; // per OpenGL spec
-        }
-        // that is very unfortunate that we have to call activeTexture here
-        gl.activeTexture(unit);
-        glTexParameteri(desc.target, GL_TEXTURE_BASE_LEVEL, baseLevel);
-        glTexParameteri(desc.target, GL_TEXTURE_MAX_LEVEL,  maxLevel);
-        ref->baseLevel = desc.baseLevel;
-        ref->maxLevel = desc.maxLevel;
-    }
-    if (UTILS_UNLIKELY(desc.swizzle != ref->swizzle)) {
-        using namespace GLUtils;
-        gl.activeTexture(unit);
-#if !defined(__EMSCRIPTEN__)  && !defined(FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2)
-        glTexParameteri(desc.target, GL_TEXTURE_SWIZZLE_R, (GLint)getSwizzleChannel(desc.swizzle[0]));
-        glTexParameteri(desc.target, GL_TEXTURE_SWIZZLE_G, (GLint)getSwizzleChannel(desc.swizzle[1]));
-        glTexParameteri(desc.target, GL_TEXTURE_SWIZZLE_B, (GLint)getSwizzleChannel(desc.swizzle[2]));
-        glTexParameteri(desc.target, GL_TEXTURE_SWIZZLE_A, (GLint)getSwizzleChannel(desc.swizzle[3]));
-#endif
-        ref->swizzle = desc.swizzle;
-    }
-}
-
-void GLDescriptorSet::bind(
-        OpenGLContext& gl,
-        HandleAllocatorGL& handleAllocator,
-        OpenGLProgram const& p,
-        descriptor_set_t set, uint32_t const* offsets, bool offsetsOnly) const noexcept {
-    // TODO: check that offsets is sized correctly
-    size_t dynamicOffsetIndex = 0;
-
-    utils::bitset64 activeDescriptorBindings = p.getActiveDescriptors(set);
-    if (offsetsOnly) {
-        activeDescriptorBindings &= dynamicBuffers;
-    }
-
-    // loop only over the active indices for this program
-    activeDescriptorBindings.forEachSetBit(
-            [this,&gl, &handleAllocator, &p, set, offsets, &dynamicOffsetIndex]
-            (size_t binding) {
-
-        // This would fail here if we're trying to set a descriptor that doesn't exist in the
-        // program. In other words, a mismatch between the program's layout and this descriptor-set.
-        assert_invariant(binding < descriptors.size());
-
-        auto const& entry = descriptors[binding];
-        std::visit(
-                [&gl, &handleAllocator, &p, &dynamicOffsetIndex, set, binding, offsets]
-                (auto&& arg) {
-            using T = std::decay_t<decltype(arg)>;
-            if constexpr (std::is_same_v<T, Buffer>) {
-                GLuint const bindingPoint = p.getBufferBinding(set, binding);
-                GLintptr const offset = arg.offset;
-                assert_invariant(arg.id || (!arg.size && !offset));
-                gl.bindBufferRange(arg.target, bindingPoint, arg.id, offset, arg.size);
-            } else if constexpr (std::is_same_v<T, DynamicBuffer>) {
-                GLuint const bindingPoint = p.getBufferBinding(set, binding);
-                GLintptr const offset = arg.offset + offsets[dynamicOffsetIndex++];
-                assert_invariant(arg.id || (!arg.size && !offset));
-                gl.bindBufferRange(arg.target, bindingPoint, arg.id, offset, arg.size);
-            } else if constexpr (std::is_same_v<T, BufferGLES2>) {
-                GLuint const bindingPoint = p.getBufferBinding(set, binding);
-                GLintptr offset = arg.offset;
-                if (arg.dynamicOffset) {
-                    offset += offsets[dynamicOffsetIndex++];
-                }
-                if (arg.bo) {
-                    auto buffer = static_cast<char const*>(arg.bo->gl.buffer) + offset;
-                    p.updateUniforms(bindingPoint, arg.bo->gl.id, buffer, arg.bo->age);
-                }
-            } else if constexpr (std::is_same_v<T, Sampler>) {
-                GLuint const unit = p.getTextureUnit(set, binding);
-                if (arg.target) {
-                    gl.bindTexture(unit, arg.target, arg.id);
-                    gl.bindSampler(unit, arg.sampler);
-                    if (UTILS_UNLIKELY(arg.ref)) {
-                        updateTextureView(gl, handleAllocator, unit, arg);
-                    }
-                } else {
-                    gl.unbindTextureUnit(unit);
-                }
-            } else if constexpr (std::is_same_v<T, SamplerWithAnisotropyWorkaround>) {
-                GLuint const unit = p.getTextureUnit(set, binding);
-                if (arg.target) {
-                    gl.bindTexture(unit, arg.target, arg.id);
-                    gl.bindSampler(unit, arg.sampler);
-                    if (UTILS_UNLIKELY(arg.ref)) {
-                        updateTextureView(gl, handleAllocator, unit, arg);
-                    }
-#if defined(GL_EXT_texture_filter_anisotropic)
-                    // Driver claims to support anisotropic filtering, but it fails when set on
-                    // the sampler, we have to set it on the texture instead.
-                    glTexParameterf(arg.target, GL_TEXTURE_MAX_ANISOTROPY_EXT,
-                            std::min(gl.gets.max_anisotropy, float(arg.anisotropy)));
-#endif
-                } else {
-                    gl.unbindTextureUnit(unit);
-                }
-            } else if constexpr (std::is_same_v<T, SamplerGLES2>) {
-                // in ES2 the sampler parameters need to be set on the texture itself
-                GLuint const unit = p.getTextureUnit(set, binding);
-                if (arg.target) {
-                    gl.bindTexture(unit, arg.target, arg.id);
-                    SamplerParams const params = arg.params;
-                    glTexParameteri(arg.target, GL_TEXTURE_MIN_FILTER,
-                            (GLint)GLUtils::getTextureFilter(params.filterMin));
-                    glTexParameteri(arg.target, GL_TEXTURE_MAG_FILTER,
-                            (GLint)GLUtils::getTextureFilter(params.filterMag));
-                    glTexParameteri(arg.target, GL_TEXTURE_WRAP_S,
-                            (GLint)GLUtils::getWrapMode(params.wrapS));
-                    glTexParameteri(arg.target, GL_TEXTURE_WRAP_T,
-                            (GLint)GLUtils::getWrapMode(params.wrapT));
-#if defined(GL_EXT_texture_filter_anisotropic)
-                    glTexParameterf(arg.target, GL_TEXTURE_MAX_ANISOTROPY_EXT,
-                            std::min(gl.gets.max_anisotropy, arg.anisotropy));
-#endif
-                } else {
-                    gl.unbindTextureUnit(unit);
-                }
-            }
-        }, entry.desc);
-    });
-    CHECK_GL_ERROR(utils::slog.e)
-}
-
-void GLDescriptorSet::validate(HandleAllocatorGL& allocator,
-        DescriptorSetLayoutHandle pipelineLayout) const {
-
-    if (UTILS_UNLIKELY(dslh != pipelineLayout)) {
-        auto* const dsl = allocator.handle_cast < GLDescriptorSetLayout const * > (dslh);
-        auto* const cur = allocator.handle_cast < GLDescriptorSetLayout const * > (pipelineLayout);
-
-        UTILS_UNUSED_IN_RELEASE
-        bool const pipelineLayoutMatchesDescriptorSetLayout = std::equal(
-                dsl->bindings.begin(), dsl->bindings.end(),
-                cur->bindings.begin(),
-                [](DescriptorSetLayoutBinding const& lhs,
-                        DescriptorSetLayoutBinding const& rhs) {
-                    return lhs.type == rhs.type &&
-                           lhs.stageFlags == rhs.stageFlags &&
-                           lhs.binding == rhs.binding &&
-                           lhs.flags == rhs.flags &&
-                           lhs.count == rhs.count;
-                });
-
-        assert_invariant(pipelineLayoutMatchesDescriptorSetLayout);
-    }
-}
-
-} // namespace filament::backend
--- a/filament/backend/src/opengl/GLDescriptorSet.h
+++ b/filament/backend/src/opengl/GLDescriptorSet.h
@@ -1,171 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef TNT_FILAMENT_BACKEND_OPENGL_GLDESCRIPTORSET_H
-#define TNT_FILAMENT_BACKEND_OPENGL_GLDESCRIPTORSET_H
-
-#include "DriverBase.h"
-
-#include "gl_headers.h"
-
-#include <private/backend/HandleAllocator.h>
-
-#include <backend/DriverEnums.h>
-#include <backend/Handle.h>
-
-#include <utils/bitset.h>
-#include <utils/FixedCapacityVector.h>
-
-#include <math/half.h>
-
-#include <array>
-#include <variant>
-
-#include <stddef.h>
-#include <stdint.h>
-
-namespace filament::backend {
-
-struct GLBufferObject;
-struct GLTexture;
-struct GLTextureRef;
-struct GLDescriptorSetLayout;
-class OpenGLProgram;
-class OpenGLContext;
-class OpenGLDriver;
-
-struct GLDescriptorSet : public HwDescriptorSet {
-
-    using HwDescriptorSet::HwDescriptorSet;
-
-    GLDescriptorSet(OpenGLContext& gl, DescriptorSetLayoutHandle dslh,
-            GLDescriptorSetLayout const* layout) noexcept;
-
-    // update a buffer descriptor in the set
-    void update(OpenGLContext& gl,
-            descriptor_binding_t binding, GLBufferObject* bo, size_t offset, size_t size) noexcept;
-
-    // update a sampler descriptor in the set
-    void update(OpenGLContext& gl,
-            descriptor_binding_t binding, GLTexture* t, SamplerParams params) noexcept;
-
-    // conceptually bind the set to the command buffer
-    void bind(
-            OpenGLContext& gl,
-            HandleAllocatorGL& handleAllocator,
-            OpenGLProgram const& p,
-            descriptor_set_t set, uint32_t const* offsets, bool offsetsOnly) const noexcept;
-
-    uint32_t getDynamicBufferCount() const noexcept {
-        return dynamicBufferCount;
-    }
-
-    void validate(HandleAllocatorGL& allocator, DescriptorSetLayoutHandle pipelineLayout) const;
-
-private:
-    // a Buffer Descriptor such as SSBO or UBO with static offset
-    struct Buffer {
-        Buffer() = default;
-        explicit Buffer(GLenum target) noexcept : target(target) { }
-        GLenum target;                          // 4
-        GLuint id = 0;                          // 4
-        uint32_t offset = 0;                    // 4
-        uint32_t size = 0;                      // 4
-    };
-
-    // a Buffer Descriptor such as SSBO or UBO with dynamic offset
-    struct DynamicBuffer {
-        DynamicBuffer() = default;
-        explicit DynamicBuffer(GLenum target) noexcept : target(target) { }
-        GLenum target;                          // 4
-        GLuint id = 0;                          // 4
-        uint32_t offset = 0;                    // 4
-        uint32_t size = 0;                      // 4
-    };
-
-    // a UBO descriptor for ES2
-    struct BufferGLES2 {
-        BufferGLES2() = default;
-        explicit BufferGLES2(bool dynamicOffset) noexcept : dynamicOffset(dynamicOffset) { }
-        GLBufferObject const* bo = nullptr;     // 8
-        uint32_t offset = 0;                    // 4
-        bool dynamicOffset = false;             // 4
-    };
-
-    // A sampler descriptor
-    struct Sampler {
-        GLenum target = 0;                      // 4
-        GLuint id = 0;                          // 4
-        GLuint sampler = 0;                     // 4
-        Handle<GLTextureRef> ref;               // 4
-        int8_t baseLevel = 0x7f;                // 1
-        int8_t maxLevel = -1;                   // 1
-        std::array<TextureSwizzle, 4> swizzle{  // 4
-                TextureSwizzle::CHANNEL_0,
-                TextureSwizzle::CHANNEL_1,
-                TextureSwizzle::CHANNEL_2,
-                TextureSwizzle::CHANNEL_3
-        };
-    };
-
-    struct SamplerWithAnisotropyWorkaround {
-        GLenum target = 0;                      // 4
-        GLuint id = 0;                          // 4
-        GLuint sampler = 0;                     // 4
-        Handle<GLTextureRef> ref;               // 4
-        math::half anisotropy = 1.0f;           // 2
-        int8_t baseLevel = 0x7f;                // 1
-        int8_t maxLevel = -1;                   // 1
-        std::array<TextureSwizzle, 4> swizzle{  // 4
-                TextureSwizzle::CHANNEL_0,
-                TextureSwizzle::CHANNEL_1,
-                TextureSwizzle::CHANNEL_2,
-                TextureSwizzle::CHANNEL_3
-        };
-    };
-
-    // A sampler descriptor for ES2
-    struct SamplerGLES2 {
-        GLenum target = 0;                      // 4
-        GLuint id = 0;                          // 4
-        SamplerParams params{};                 // 4
-        float anisotropy = 1.0f;                // 4
-    };
-    struct Descriptor {
-        std::variant<
-                Buffer,
-                DynamicBuffer,
-                BufferGLES2,
-                Sampler,
-                SamplerWithAnisotropyWorkaround,
-                SamplerGLES2> desc;
-    };
-    static_assert(sizeof(Descriptor) <= 32);
-
-    template<typename T>
-    static void updateTextureView(OpenGLContext& gl,
-            HandleAllocatorGL& handleAllocator, GLuint unit, T const& desc) noexcept;
-
-    utils::FixedCapacityVector<Descriptor> descriptors;     // 16
-    utils::bitset64 dynamicBuffers;                         // 8
-    DescriptorSetLayoutHandle dslh;                         // 4
-    uint8_t dynamicBufferCount = 0;                         // 1
-};
-static_assert(sizeof(GLDescriptorSet) <= 32);
-
-} // namespace filament::backend
-
-#endif //TNT_FILAMENT_BACKEND_OPENGL_GLDESCRIPTORSET_H
--- a/filament/backend/src/opengl/GLDescriptorSetLayout.h
+++ b/filament/backend/src/opengl/GLDescriptorSetLayout.h
@@ -1,52 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef TNT_FILAMENT_BACKEND_OPENGL_GLDESCRIPTORSETLAYOUT_H
-#define TNT_FILAMENT_BACKEND_OPENGL_GLDESCRIPTORSETLAYOUT_H
-
-#include "DriverBase.h"
-
-#include <backend/DriverEnums.h>
-
-#include <algorithm>
-#include <utility>
-
-#include <stdint.h>
-
-namespace filament::backend {
-
-struct GLDescriptorSetLayout : public HwDescriptorSetLayout, public DescriptorSetLayout {
-    using HwDescriptorSetLayout::HwDescriptorSetLayout;
-    explicit GLDescriptorSetLayout(DescriptorSetLayout&& layout) noexcept
-            : DescriptorSetLayout(std::move(layout)) {
-
-        std::sort(bindings.begin(), bindings.end(),
-                [](auto&& lhs, auto&& rhs){
-            return lhs.binding < rhs.binding;
-        });
-
-        auto p = std::max_element(bindings.cbegin(), bindings.cend(),
-                [](auto const& lhs, auto const& rhs) {
-            return lhs.binding < rhs.binding;
-        });
-        maxDescriptorBinding = p->binding;
-    }
-    uint8_t maxDescriptorBinding = 0;
-};
-
-} // namespace filament::backend
-
-#endif //TNT_FILAMENT_BACKEND_OPENGL_GLDESCRIPTORSETLAYOUT_H
--- a/filament/backend/src/opengl/GLTexture.h
+++ b/filament/backend/src/opengl/GLTexture.h
@@ -21,32 +21,12 @@

 #include "gl_headers.h"

-#include <backend/Handle.h>
-#include <backend/DriverEnums.h>
 #include <backend/platforms/OpenGLPlatform.h>

-#include <array>
-
 #include <stdint.h>

 namespace filament::backend {

-struct GLTextureRef {
-    GLTextureRef() = default;
-    // view reference counter
-    uint16_t count = 1;
-    // current per-view values of the texture (in GL we can only have a single View active at
-    // a time, and this tracks that state). It's used to avoid unnecessarily change state.
-    int8_t baseLevel = 127;
-    int8_t maxLevel = -1;
-    std::array<TextureSwizzle, 4> swizzle{
-            TextureSwizzle::CHANNEL_0,
-            TextureSwizzle::CHANNEL_1,
-            TextureSwizzle::CHANNEL_2,
-            TextureSwizzle::CHANNEL_3
-    };
-};
-
 struct GLTexture : public HwTexture {
    using HwTexture::HwTexture;
    struct GL {
@@ -64,14 +44,8 @@ struct GLTexture : public HwTexture {
        bool imported           : 1;
        uint8_t sidecarSamples  : 4;
        uint8_t reserved1       : 3;
-        std::array<TextureSwizzle, 4> swizzle{
-                TextureSwizzle::CHANNEL_0,
-                TextureSwizzle::CHANNEL_1,
-                TextureSwizzle::CHANNEL_2,
-                TextureSwizzle::CHANNEL_3
-        };
    } gl;
-    mutable Handle<GLTextureRef> ref;
+
    OpenGLPlatform::ExternalTexture* externalTexture = nullptr;
 };

--- a/filament/backend/src/opengl/OpenGLContext.cpp
+++ b/filament/backend/src/opengl/OpenGLContext.cpp
@@ -676,7 +676,6 @@ void OpenGLContext::initExtensionsGLES(Extensions* ext, GLint major, GLint minor
 #ifndef __EMSCRIPTEN__
    ext->EXT_debug_marker = exts.has("GL_EXT_debug_marker"sv);
 #endif
-    ext->EXT_depth_clamp = exts.has("GL_EXT_depth_clamp"sv);
    ext->EXT_discard_framebuffer = exts.has("GL_EXT_discard_framebuffer"sv);
 #ifndef __EMSCRIPTEN__
    ext->EXT_disjoint_timer_query = exts.has("GL_EXT_disjoint_timer_query"sv);
@@ -747,7 +746,6 @@ void OpenGLContext::initExtensionsGL(Extensions* ext, GLint major, GLint minor)
    ext->EXT_color_buffer_half_float = true;  // Assumes core profile.
    ext->EXT_clip_cull_distance = true;
    ext->EXT_debug_marker = exts.has("GL_EXT_debug_marker"sv);
-    ext->EXT_depth_clamp = true;
    ext->EXT_discard_framebuffer = false;
    ext->EXT_disjoint_timer_query = true;
    ext->EXT_multisampled_render_to_texture = false;
--- a/filament/backend/src/opengl/OpenGLContext.h
+++ b/filament/backend/src/opengl/OpenGLContext.h
@@ -60,19 +60,10 @@ public:
    struct RenderPrimitive {
        static_assert(MAX_VERTEX_ATTRIBUTE_COUNT <= 16);

-        GLuint vao[2] = {};                                     // 8
+        GLuint vao[2] = {};                                     // 4
        GLuint elementArray = 0;                                // 4
-        GLenum indicesType = 0;                                 // 4
-
-        // The optional 32-bit handle to a GLVertexBuffer is necessary only if the referenced
-        // VertexBuffer supports buffer objects. If this is zero, then the VBO handles array is
-        // immutable.
-        Handle<HwVertexBuffer> vertexBufferWithObjects;         // 4
-
        mutable utils::bitset<uint16_t> vertexAttribArray;      // 2

-        uint8_t reserved[2] = {};                               // 2
-
        // if this differs from vertexBufferWithObjects->bufferObjectsVersion, this VAO needs to
        // be updated (see OpenGLDriver::updateVertexArrayObject())
        uint8_t vertexBufferVersion = 0;                        // 1
@@ -85,11 +76,16 @@ public:
        // See OpenGLContext::bindVertexArray()
        uint8_t nameVersion = 0;                                // 1

-        // Size in bytes of indices in the index buffer (1 or 2)
-        uint8_t indicesShift = 0;                                // 1
+        // Size in bytes of indices in the index buffer
+        uint8_t indicesSize = 0;                                // 1
+
+        // The optional 32-bit handle to a GLVertexBuffer is necessary only if the referenced
+        // VertexBuffer supports buffer objects. If this is zero, then the VBO handles array is
+        // immutable.
+        Handle<HwVertexBuffer> vertexBufferWithObjects;         // 4

        GLenum getIndicesType() const noexcept {
-            return indicesType;
+            return indicesSize == 4 ? GL_UNSIGNED_INT : GL_UNSIGNED_SHORT;
        }
    } gl;

@@ -224,9 +220,8 @@ public:
        bool EXT_color_buffer_float;
        bool EXT_color_buffer_half_float;
        bool EXT_debug_marker;
-        bool EXT_depth_clamp;
-        bool EXT_discard_framebuffer;
        bool EXT_disjoint_timer_query;
+        bool EXT_discard_framebuffer;
        bool EXT_multisampled_render_to_texture2;
        bool EXT_multisampled_render_to_texture;
        bool EXT_protected_textures;
@@ -244,10 +239,10 @@ public:
        bool KHR_parallel_shader_compile;
        bool KHR_texture_compression_astc_hdr;
        bool KHR_texture_compression_astc_ldr;
-        bool OES_EGL_image_external_essl3;
-        bool OES_depth24;
        bool OES_depth_texture;
+        bool OES_depth24;
        bool OES_packed_depth_stencil;
+        bool OES_EGL_image_external_essl3;
        bool OES_rgb8_rgba8;
        bool OES_standard_derivatives;
        bool OES_texture_npot;
@@ -478,6 +473,12 @@ public:

    void unbindEverything() noexcept;
    void synchronizeStateAndCache(size_t index) noexcept;
+    void setEs2UniformBinding(size_t index, GLuint id, void const* data, uint16_t age) noexcept {
+        mUniformBindings[index] = { id, data, age };
+    }
+    auto getEs2UniformBinding(size_t index) const noexcept {
+        return mUniformBindings[index];
+    }

 #ifndef FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2
    GLuint getSamplerSlow(SamplerParams sp) const noexcept;
@@ -504,6 +505,9 @@ private:
    std::vector<std::function<void(OpenGLContext&)>> mDestroyWithNormalContext;
    RenderPrimitive mDefaultVAO;
    std::optional<GLuint> mDefaultFbo[2];
+    std::array<
+            std::tuple<GLuint, void const*, uint16_t>,
+            CONFIG_UNIFORM_BINDING_COUNT> mUniformBindings = {};
    mutable tsl::robin_map<SamplerParams, GLuint,
            SamplerParams::Hasher, SamplerParams::EqualTo> mSamplerMap;

@@ -623,7 +627,6 @@ constexpr size_t OpenGLContext::getIndexForCap(GLenum cap) noexcept { //NOLINT
 #ifdef BACKEND_OPENGL_VERSION_GL
        case GL_PROGRAM_POINT_SIZE:             index = 10; break;
 #endif
-        case GL_DEPTH_CLAMP:                    index = 11; break;
        default: break;
    }
    assert_invariant(index < state.enables.caps.size());
--- a/filament/backend/src/opengl/OpenGLDriver.cpp
+++ b/filament/backend/src/opengl/OpenGLDriver.cpp
--- a/filament/backend/src/opengl/OpenGLDriver.h
+++ b/filament/backend/src/opengl/OpenGLDriver.h
@@ -21,8 +21,6 @@
 #include "OpenGLContext.h"
 #include "OpenGLTimerQuery.h"
 #include "GLBufferObject.h"
-#include "GLDescriptorSet.h"
-#include "GLDescriptorSetLayout.h"
 #include "GLTexture.h"
 #include "ShaderCompilerService.h"

@@ -38,7 +36,6 @@
 #include "private/backend/Driver.h"
 #include "private/backend/HandleAllocator.h"

-#include <utils/bitset.h>
 #include <utils/FixedCapacityVector.h>
 #include <utils/compiler.h>
 #include <utils/debug.h>
@@ -55,7 +52,6 @@
 #include <tuple>
 #include <type_traits>
 #include <utility>
-#include <variant>
 #include <vector>

 #include <stddef.h>
@@ -85,7 +81,7 @@ public:
            const Platform::DriverConfig& driverConfig) noexcept;

    class DebugMarker {
-        UTILS_UNUSED OpenGLDriver& driver;
+        OpenGLDriver& driver;
    public:
        DebugMarker(OpenGLDriver& driver, const char* string) noexcept;
        ~DebugMarker() noexcept;
@@ -127,6 +123,16 @@ public:
        } gl;
    };

+    struct GLSamplerGroup : public HwSamplerGroup {
+        using HwSamplerGroup::HwSamplerGroup;
+        struct Entry {
+            Handle<HwTexture> th;
+            GLuint sampler = 0u;
+        };
+        utils::FixedCapacityVector<Entry> textureUnitEntries;
+        explicit GLSamplerGroup(size_t size) noexcept : textureUnitEntries(size) { }
+    };
+
    struct GLRenderPrimitive : public HwRenderPrimitive {
        using HwRenderPrimitive::HwRenderPrimitive;
        OpenGLContext::RenderPrimitive gl;
@@ -139,10 +145,6 @@ public:

    using GLTimerQuery = filament::backend::GLTimerQuery;

-    using GLDescriptorSetLayout = filament::backend::GLDescriptorSetLayout;
-
-    using GLDescriptorSet = filament::backend::GLDescriptorSet;
-
    struct GLStream : public HwStream {
        using HwStream::HwStream;
        struct Info {
@@ -315,6 +317,10 @@ private:
    void resolvePass(ResolveAction action, GLRenderTarget const* rt,
            TargetBufferFlags discardFlags) noexcept;

+    const std::array<GLSamplerGroup*, Program::SAMPLER_BINDING_COUNT>& getSamplerBindings() const {
+        return mSamplerBindings;
+    }
+
    using AttachmentArray = std::array<GLenum, MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT + 2>;
    static GLsizei getAttachments(AttachmentArray& attachments, TargetBufferFlags buffers,
            bool isDefaultFramebuffer) noexcept;
@@ -327,16 +333,8 @@ private:
    GLboolean mRenderPassStencilWrite{};

    GLRenderPrimitive const* mBoundRenderPrimitive = nullptr;
-    OpenGLProgram* mBoundProgram = nullptr;
    bool mValidProgram = false;
-    utils::bitset8 mInvalidDescriptorSetBindings;
-    utils::bitset8 mInvalidDescriptorSetBindingOffsets;
-    void updateDescriptors(utils::bitset8 invalidDescriptorSets) noexcept;

-    struct {
-        backend::DescriptorSetHandle dsh;
-        std::array<uint32_t, CONFIG_UNIFORM_BINDING_COUNT> offsets;
-    } mBoundDescriptorSets[MAX_DESCRIPTOR_SET_COUNT];

    void clearWithRasterPipe(TargetBufferFlags clearFlags,
            math::float4 const& linearColor, GLfloat depth, GLint stencil) noexcept;
@@ -348,6 +346,9 @@ private:
    // ES2 only. Uniform buffer emulation binding points
    GLuint mLastAssignedEmulatedUboId = 0;

+    // sampler buffer binding points (nullptr if not used)
+    std::array<GLSamplerGroup*, Program::SAMPLER_BINDING_COUNT> mSamplerBindings = {};   // 4 pointers
+
    // this must be accessed from the driver thread only
    std::vector<GLTexture*> mTexturesWithStreamsAttached;

@@ -358,6 +359,8 @@ private:
    void detachStream(GLTexture* t) noexcept;
    void replaceStream(GLTexture* t, GLStream* stream) noexcept;

+    void updateTextureLodRange(GLTexture* texture, int8_t targetLevel) noexcept;
+
 #ifndef FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2
    // tasks executed on the main thread after the fence signaled
    void whenGpuCommandsComplete(const std::function<void()>& fn) noexcept;
@@ -381,7 +384,6 @@ private:
    bool mRec709OutputColorspace = false;

    PushConstantBundle* mCurrentPushConstants = nullptr;
-    PipelineLayout::SetLayout mCurrentSetLayout;
 };

 // ------------------------------------------------------------------------------------------------
--- a/filament/backend/src/opengl/OpenGLProgram.cpp
+++ b/filament/backend/src/opengl/OpenGLProgram.cpp
@@ -17,7 +17,6 @@
 #include "OpenGLProgram.h"

 #include "GLUtils.h"
-#include "GLTexture.h"
 #include "OpenGLDriver.h"
 #include "ShaderCompilerService.h"

@@ -25,7 +24,6 @@
 #include <backend/Program.h>
 #include <backend/Handle.h>

-#include <utils/BitmaskEnum.h>
 #include <utils/compiler.h>
 #include <utils/debug.h>
 #include <utils/FixedCapacityVector.h>
@@ -34,10 +32,9 @@

 #include <algorithm>
 #include <array>
-#include <algorithm>
-#include <new>
 #include <string_view>
 #include <utility>
+#include <new>

 #include <stddef.h>
 #include <stdint.h>
@@ -49,8 +46,9 @@ using namespace utils;
 using namespace backend;

 struct OpenGLProgram::LazyInitializationData {
-    Program::DescriptorSetInfo descriptorBindings;
-    Program::BindingUniformsInfo bindingUniformInfo;
+    Program::UniformBlockInfo uniformBlockInfo;
+    Program::SamplerGroupInfo samplerGroupInfo;
+    std::array<Program::UniformInfo, Program::UNIFORM_BINDING_COUNT> bindingUniformInfo;
    utils::FixedCapacityVector<Program::PushConstant> vertexPushConstants;
    utils::FixedCapacityVector<Program::PushConstant> fragmentPushConstants;
 };
@@ -59,14 +57,16 @@ struct OpenGLProgram::LazyInitializationData {
 OpenGLProgram::OpenGLProgram() noexcept = default;

 OpenGLProgram::OpenGLProgram(OpenGLDriver& gld, Program&& program) noexcept
-        : HwProgram(std::move(program.getName())), mRec709Location(-1) {
+        : HwProgram(std::move(program.getName())) {
    auto* const lazyInitializationData = new(std::nothrow) LazyInitializationData();
+    lazyInitializationData->samplerGroupInfo = std::move(program.getSamplerGroupInfo());
    if (UTILS_UNLIKELY(gld.getContext().isES2())) {
        lazyInitializationData->bindingUniformInfo = std::move(program.getBindingUniformInfo());
+    } else {
+        lazyInitializationData->uniformBlockInfo = std::move(program.getUniformBlockBindings());
    }
    lazyInitializationData->vertexPushConstants = std::move(program.getPushConstants(ShaderStage::VERTEX));
    lazyInitializationData->fragmentPushConstants = std::move(program.getPushConstants(ShaderStage::FRAGMENT));
-    lazyInitializationData->descriptorBindings = std::move(program.getDescriptorBindings());

    ShaderCompilerService& compiler = gld.getShaderCompilerService();
    mToken = compiler.createProgram(name, std::move(program));
@@ -124,86 +124,36 @@ void OpenGLProgram::initializeProgramState(OpenGLContext& context, GLuint progra

    SYSTRACE_CALL();

-    // from the pipeline layout we compute a mapping from {set, binding} to {binding}
-    // for both buffers and textures
-
-    for (auto&& entry: lazyInitializationData.descriptorBindings) {
-        std::sort(entry.begin(), entry.end(),
-                [](Program::Descriptor const& lhs, Program::Descriptor const& rhs) {
-                    return lhs.binding < rhs.binding;
-                });
-    }
-
-    GLuint tmu = 0;
-    GLuint binding = 0;
-
-    // needed for samplers
-    context.useProgram(program);
-
-    UTILS_NOUNROLL
-    for (backend::descriptor_set_t set = 0; set < MAX_DESCRIPTOR_SET_COUNT; set++) {
-        for (Program::Descriptor const& entry: lazyInitializationData.descriptorBindings[set]) {
-            switch (entry.type) {
-                case DescriptorType::UNIFORM_BUFFER:
-                case DescriptorType::SHADER_STORAGE_BUFFER: {
-                    if (!entry.name.empty()) {
 #ifndef FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2
-                        if (UTILS_LIKELY(!context.isES2())) {
-                            GLuint const index = glGetUniformBlockIndex(program,
-                                    entry.name.c_str());
-                            if (index != GL_INVALID_INDEX) {
-                                // this can fail if the program doesn't use this descriptor
-                                glUniformBlockBinding(program, index, binding);
-                                mBindingMap.insert(set, entry.binding,
-                                        { binding, entry.type });
-                                ++binding;
-                            }
-                        } else
-#endif
-                        {
-                            auto pos = std::find_if(lazyInitializationData.bindingUniformInfo.begin(),
-                                    lazyInitializationData.bindingUniformInfo.end(),
-                                    [&name = entry.name](const auto& item) {
-                                return std::get<1>(item) == name;
-                            });
-                            if (pos != lazyInitializationData.bindingUniformInfo.end()) {
-                                binding = std::get<0>(*pos);
-                                mBindingMap.insert(set, entry.binding, { binding, entry.type });
-                            }
-                        }
-                    }
-                    break;
+    if (!context.isES2()) {
+        // Note: This is only needed, because the layout(binding=) syntax is not permitted in glsl
+        // (ES3.0 and GL4.1). The backend needs a way to associate a uniform block to a binding point.
+        UTILS_NOUNROLL
+        for (GLuint binding = 0, n = lazyInitializationData.uniformBlockInfo.size();
+                binding < n; binding++) {
+            auto const& name = lazyInitializationData.uniformBlockInfo[binding];
+            if (!name.empty()) {
+                GLuint const index = glGetUniformBlockIndex(program, name.c_str());
+                if (index != GL_INVALID_INDEX) {
+                    glUniformBlockBinding(program, index, binding);
                }
-                case DescriptorType::SAMPLER: {
-                    if (!entry.name.empty()) {
-                        GLint const loc = glGetUniformLocation(program, entry.name.c_str());
-                        if (loc >= 0) {
-                            // this can fail if the program doesn't use this descriptor
-                            mBindingMap.insert(set, entry.binding, { tmu, entry.type });
-                            glUniform1i(loc, GLint(tmu));
-                            ++tmu;
-                        }
-                    }
-                    break;
-                }
-                case DescriptorType::INPUT_ATTACHMENT:
-                    break;
+                CHECK_GL_ERROR(utils::slog.e)
            }
-            CHECK_GL_ERROR(utils::slog.e)
        }
-    }
-
-    if (context.isES2()) {
+    } else
+#endif
+    {
        // ES2 initialization of (fake) UBOs
        UniformsRecord* const uniformsRecords = new(std::nothrow) UniformsRecord[Program::UNIFORM_BINDING_COUNT];
        UTILS_NOUNROLL
-        for (auto&& [index, name, uniforms] : lazyInitializationData.bindingUniformInfo) {
-            uniformsRecords[index].locations.reserve(uniforms.size());
-            uniformsRecords[index].locations.resize(uniforms.size());
+        for (GLuint binding = 0, n = Program::UNIFORM_BINDING_COUNT; binding < n; binding++) {
+            Program::UniformInfo& uniforms = lazyInitializationData.bindingUniformInfo[binding];
+            uniformsRecords[binding].locations.reserve(uniforms.size());
+            uniformsRecords[binding].locations.resize(uniforms.size());
            for (size_t j = 0, c = uniforms.size(); j < c; j++) {
                GLint const loc = glGetUniformLocation(program, uniforms[j].name.c_str());
-                uniformsRecords[index].locations[j] = loc;
-                if (UTILS_UNLIKELY(index == 0)) {
+                uniformsRecords[binding].locations[j] = loc;
+                if (UTILS_UNLIKELY(binding == 0)) {
                    // This is a bit of a gross hack here, we stash the location of
                    // "frameUniforms.rec709", which obviously the backend shouldn't know about,
                    // which is used for emulating the "rec709" colorspace in the shader.
@@ -215,11 +165,51 @@ void OpenGLProgram::initializeProgramState(OpenGLContext& context, GLuint progra
                    }
                }
            }
-            uniformsRecords[index].uniforms = std::move(uniforms);
+            uniformsRecords[binding].uniforms = std::move(uniforms);
        }
        mUniformsRecords = uniformsRecords;
    }

+    uint8_t usedBindingCount = 0;
+    uint8_t tmu = 0;
+
+    UTILS_NOUNROLL
+    for (size_t i = 0, c = lazyInitializationData.samplerGroupInfo.size(); i < c; i++) {
+        auto const& samplers = lazyInitializationData.samplerGroupInfo[i].samplers;
+        if (samplers.empty()) {
+            // this binding point doesn't have any samplers, skip it.
+            continue;
+        }
+
+        // keep this in the loop, so we skip it in the rare case a program doesn't have
+        // sampler. The context cache will prevent repeated calls to GL.
+        context.useProgram(program);
+
+        bool atLeastOneSamplerUsed = false;
+        UTILS_NOUNROLL
+        for (const Program::Sampler& sampler: samplers) {
+            // find its location and associate a TMU to it
+            GLint const loc = glGetUniformLocation(program, sampler.name.c_str());
+            if (loc >= 0) {
+                // this can fail if the program doesn't use this sampler
+                glUniform1i(loc, tmu);
+                atLeastOneSamplerUsed = true;
+            }
+            tmu++;
+        }
+
+        // if this program doesn't use any sampler from this HwSamplerGroup, just cancel the
+        // whole group.
+        if (atLeastOneSamplerUsed) {
+            // Cache the sampler uniform locations for each interface block
+            mUsedSamplerBindingPoints[usedBindingCount] = i;
+            usedBindingCount++;
+        } else {
+            tmu -= samplers.size();
+        }
+    }
+    mUsedBindingsCount = usedBindingCount;
+
    auto& vertexConstants = lazyInitializationData.vertexPushConstants;
    auto& fragmentConstants = lazyInitializationData.fragmentPushConstants;

@@ -236,8 +226,41 @@ void OpenGLProgram::initializeProgramState(OpenGLContext& context, GLuint progra
    }
 }

-void OpenGLProgram::updateUniforms(
-        uint32_t index, GLuint id, void const* buffer, uint16_t age) const noexcept {
+void OpenGLProgram::updateSamplers(OpenGLDriver* const gld) const noexcept {
+    using GLTexture = OpenGLDriver::GLTexture;
+
+#ifndef FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2
+    bool const es2 = gld->getContext().isES2();
+#endif
+
+    // cache a few member variable locally, outside the loop
+    auto const& UTILS_RESTRICT samplerBindings = gld->getSamplerBindings();
+    auto const& UTILS_RESTRICT usedBindingPoints = mUsedSamplerBindingPoints;
+
+    for (uint8_t i = 0, tmu = 0, n = mUsedBindingsCount; i < n; i++) {
+        size_t const binding = usedBindingPoints[i];
+        assert_invariant(binding < Program::SAMPLER_BINDING_COUNT);
+        auto const * const sb = samplerBindings[binding];
+        assert_invariant(sb);
+        if (!sb) continue; // should never happen, this would be a user error.
+        for (uint8_t j = 0, m = sb->textureUnitEntries.size(); j < m; ++j, ++tmu) { // "<=" on purpose here
+            Handle<HwTexture> th = sb->textureUnitEntries[j].th;
+            if (th) { // program may not use all samplers of sampler group
+                GLTexture const* const t = gld->handle_cast<GLTexture const*>(th);
+                gld->bindTexture(tmu, t);
+#ifndef FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2
+                if (UTILS_LIKELY(!es2)) {
+                    GLuint const s = sb->textureUnitEntries[j].sampler;
+                    gld->bindSampler(tmu, s);
+                }
+#endif
+            }
+        }
+    }
+    CHECK_GL_ERROR(utils::slog.e)
+}
+
+void OpenGLProgram::updateUniforms(uint32_t index, GLuint id, void const* buffer, uint16_t age) noexcept {
    assert_invariant(mUniformsRecords);
    assert_invariant(buffer);

--- a/filament/backend/src/opengl/OpenGLProgram.h
+++ b/filament/backend/src/opengl/OpenGLProgram.h
@@ -19,20 +19,17 @@

 #include "DriverBase.h"

-#include "BindingMap.h"
 #include "OpenGLContext.h"
 #include "ShaderCompilerService.h"

 #include <private/backend/Driver.h>
-
-#include <backend/DriverEnums.h>
 #include <backend/Program.h>

-#include <utils/bitset.h>
 #include <utils/compiler.h>
 #include <utils/FixedCapacityVector.h>
 #include <utils/Slice.h>

+#include <array>
 #include <limits>

 #include <stddef.h>
@@ -72,25 +69,32 @@ public:
        }

        context.useProgram(gl.program);
+        if (UTILS_UNLIKELY(mUsedBindingsCount)) {
+            // We rely on GL state tracking to avoid unnecessary glBindTexture / glBindSampler
+            // calls.
+
+            // we need to do this if:
+            // - the content of mSamplerBindings has changed
+            // - the content of any bound sampler buffer has changed
+            // ... since last time we used this program
+
+            // Turns out the former might be relatively cheap to check, the latter requires
+            // a bit less. Compared to what updateSamplers() actually does, which is
+            // pretty little, I'm not sure if we'll get ahead.
+
+            updateSamplers(gld);
+        }
        return true;
    }

-    GLuint getBufferBinding(descriptor_set_t set, descriptor_binding_t binding) const noexcept {
-        return mBindingMap.get(set, binding);
-    }
-
-    GLuint getTextureUnit(descriptor_set_t set, descriptor_binding_t binding) const noexcept {
-        return mBindingMap.get(set, binding);
-    }
-
-    utils::bitset64 getActiveDescriptors(descriptor_set_t set) const noexcept {
-        return mBindingMap.getActiveDescriptors(set);
-    }
-
    // For ES2 only
-    void updateUniforms(uint32_t index, GLuint id, void const* buffer, uint16_t age) const noexcept;
+    void updateUniforms(uint32_t index, GLuint id, void const* buffer, uint16_t age) noexcept;
    void setRec709ColorSpace(bool rec709) const noexcept;

+    struct {
+        GLuint program = 0;
+    } gl;                                               // 4 bytes
+
    PushConstantBundle getPushConstants() {
        auto fragBegin = mPushConstants.begin() + mPushConstantFragmentStageOffset;
        return {
@@ -108,15 +112,22 @@ private:
    void initializeProgramState(OpenGLContext& context, GLuint program,
            LazyInitializationData& lazyInitializationData) noexcept;

-    BindingMap mBindingMap;     // 8 bytes + out-of-line 256 bytes
+    void updateSamplers(OpenGLDriver* gld) const noexcept;
+
+    // number of bindings actually used by this program
+    std::array<uint8_t, Program::SAMPLER_BINDING_COUNT> mUsedSamplerBindingPoints;   // 4 bytes

    ShaderCompilerService::program_token_t mToken{};    // 16 bytes

-    // Note that this can be replaced with a raw pointer and an uint8_t (for size) to reduce the
-    // size of the container to 9 bytes if there is a need in the future.
-    utils::FixedCapacityVector<std::pair<GLint, ConstantType>> mPushConstants;// 16 bytes
+    uint8_t mUsedBindingsCount = 0u;                    // 1 byte
+    UTILS_UNUSED uint8_t padding[2] = {};               // 2 byte
+
+    // Push constant array offset for fragment stage constants.
+    uint8_t mPushConstantFragmentStageOffset = 0u;      // 1 byte

    // only needed for ES2
+    GLint mRec709Location = -1;                         // 4 bytes
+
    using LocationInfo = utils::FixedCapacityVector<GLint>;
    struct UniformsRecord {
        Program::UniformInfo uniforms;
@@ -124,20 +135,15 @@ private:
        mutable GLuint id = 0;
        mutable uint16_t age = std::numeric_limits<uint16_t>::max();
    };
-    UniformsRecord const* mUniformsRecords = nullptr;
-    GLint mRec709Location : 24;     // 4 bytes
+    UniformsRecord const* mUniformsRecords = nullptr;               // 8 bytes

-    // Push constant array offset for fragment stage constants.
-    GLint mPushConstantFragmentStageOffset : 8;      // 1 byte
-
-public:
-    struct {
-        GLuint program = 0;
-    } gl;                                               // 4 bytes
+    // Note that this can be replaced with a raw pointer and an uint8_t (for size) to reduce the
+    // size of the container to 9 bytes if there is a need in the future.
+    utils::FixedCapacityVector<std::pair<GLint, ConstantType>> mPushConstants;// 16 bytes
 };

-// if OpenGLProgram is larger than 96 bytes, it'll fall in a larger Handle bucket.
-static_assert(sizeof(OpenGLProgram) <= 96); // currently 96 bytes
+// if OpenGLProgram is larger tha 64 bytes, it'll fall in a larger Handle bucket.
+static_assert(sizeof(OpenGLProgram) <= 64); // currently 64 bytes

 } // namespace filament::backend

--- a/filament/backend/src/opengl/OpenGLTimerQuery.cpp
+++ b/filament/backend/src/opengl/OpenGLTimerQuery.cpp
@@ -143,25 +143,21 @@ void TimerQueryNativeFactory::endTimeElapsedQuery(OpenGLDriver& driver, GLTimerQ

    driver.runEveryNowAndThen([&context = mContext, weak]() -> bool {
        auto state = weak.lock();
-        if (!state) {
-            // The timer query state has been destroyed on the way, very likely due to the IBL
-            // prefilter context destruction. We still return true to get this element removed from
-            // the query list.
-            return true;
+        if (state) {
+            GLuint available = 0;
+            context.procs.getQueryObjectuiv(state->gl.query, GL_QUERY_RESULT_AVAILABLE, &available);
+            CHECK_GL_ERROR(utils::slog.e)
+            if (!available) {
+                // we need to try this one again later
+                return false;
+            }
+            GLuint64 elapsedTime = 0;
+            // we won't end-up here if we're on ES and don't have GL_EXT_disjoint_timer_query
+            context.procs.getQueryObjectui64v(state->gl.query, GL_QUERY_RESULT, &elapsedTime);
+            state->elapsed.store((int64_t)elapsedTime, std::memory_order_relaxed);
+        } else {
+            state->elapsed.store(int64_t(TimerQueryResult::ERROR), std::memory_order_relaxed);
        }
-
-        GLuint available = 0;
-        context.procs.getQueryObjectuiv(state->gl.query, GL_QUERY_RESULT_AVAILABLE, &available);
-        CHECK_GL_ERROR(utils::slog.e)
-        if (!available) {
-            // we need to try this one again later
-            return false;
-        }
-        GLuint64 elapsedTime = 0;
-        // we won't end-up here if we're on ES and don't have GL_EXT_disjoint_timer_query
-        context.procs.getQueryObjectui64v(state->gl.query, GL_QUERY_RESULT, &elapsedTime);
-        state->elapsed.store((int64_t)elapsedTime, std::memory_order_relaxed);
-
        return true;
    });
 }
--- a/filament/backend/src/opengl/ShaderCompilerService.cpp
+++ b/filament/backend/src/opengl/ShaderCompilerService.cpp
@@ -26,28 +26,16 @@

 #include <utils/compiler.h>
 #include <utils/CString.h>
-#include <utils/debug.h>
-#include <utils/FixedCapacityVector.h>
 #include <utils/JobSystem.h>
 #include <utils/Log.h>
-#include <utils/ostream.h>
-#include <utils/Panic.h>
 #include <utils/Systrace.h>

-#include <array>
 #include <cctype>
 #include <chrono>
-#include <mutex>
-#include <memory>
 #include <string>
 #include <string_view>
-#include <thread>
-#include <utility>
 #include <variant>

-#include <stddef.h>
-#include <stdint.h>
-
 namespace filament::backend {

 using namespace utils;
@@ -488,12 +476,6 @@ GLuint ShaderCompilerService::initialize(program_token_t& token) noexcept {
    // check status of program linking and shader compilation, logs error and free all resources
    // in case of error.
    bool const success = checkProgramStatus(token);
-
-    // Unless we have matdbg, we panic if a program is invalid. Otherwise, we'd get a UB.
-    // The compilation error has been logged to log.e by this point.
-    FILAMENT_CHECK_POSTCONDITION(FILAMENT_ENABLE_MATDBG || success)
-            << "OpenGL program " << token->name.c_str_safe() << " failed to link or compile";
-
    if (UTILS_LIKELY(success)) {
        program = token->gl.program;
        // no need to keep the shaders around
@@ -597,31 +579,24 @@ void ShaderCompilerService::compileShaders(OpenGLContext& context,
                version = "#version 310 es\n";
            }

-            std::array<std::string_view, 5> sources = {
-                version,
-                prolog,
-                specializationConstantString,
-                packingFunctions,
-                { body.data(), body.size() - 1 }  // null-terminated
+            const std::array<const char*, 5> sources = {
+                    version.data(),
+                    prolog.data(),
+                    specializationConstantString.c_str(),
+                    packingFunctions.data(),
+                    body.data()
            };

-            // Some of the sources may be zero-length. Remove them as to avoid passing lengths of
-            // zero to glShaderSource(). glShaderSource should work with lengths of zero, but some
-            // drivers instead interpret zero as a sentinel for a null-terminated string.
-            auto partitionPoint = std::stable_partition(
-                    sources.begin(), sources.end(), [](std::string_view s) { return !s.empty(); });
-            size_t count = std::distance(sources.begin(), partitionPoint);
-
-            std::array<const char*, 5> shaderStrings;
-            std::array<GLint, 5> lengths;
-            for (size_t i = 0; i < count; i++) {
-                shaderStrings[i] = sources[i].data();
-                lengths[i] = sources[i].size();
-            }
+            const std::array<GLint, 5> lengths = {
+                    (GLint)version.length(),
+                    (GLint)prolog.length(),
+                    (GLint)specializationConstantString.length(),
+                    (GLint)packingFunctions.length(),
+                    (GLint)body.length() - 1 // null terminated
+            };

            GLuint const shaderId = glCreateShader(glShaderType);
-            glShaderSource(shaderId, count, shaderStrings.data(), lengths.data());
-
+            glShaderSource(shaderId, sources.size(), sources.data(), lengths.data());
            glCompileShader(shaderId);

 #ifndef NDEBUG
--- a/filament/backend/src/opengl/gl_headers.h
+++ b/filament/backend/src/opengl/gl_headers.h
@@ -201,12 +201,6 @@ using namespace glext;
 #   define GL_CLIP_DISTANCE1                        0x3001
 #endif

-#if defined(GL_EXT_depth_clamp)
-#   define GL_DEPTH_CLAMP                           GL_DEPTH_CLAMP_EXT
-#else
-#   define GL_DEPTH_CLAMP                           0x864F
-#endif
-
 #if defined(GL_KHR_debug)
 #   define GL_DEBUG_OUTPUT                          GL_DEBUG_OUTPUT_KHR
 #   define GL_DEBUG_OUTPUT_SYNCHRONOUS              GL_DEBUG_OUTPUT_SYNCHRONOUS_KHR
--- a/filament/backend/src/vulkan/VulkanBlitter.cpp
+++ b/filament/backend/src/vulkan/VulkanBlitter.cpp
@@ -15,7 +15,6 @@
 */

 #include "VulkanBlitter.h"
-#include "VulkanCommands.h"
 #include "VulkanContext.h"
 #include "VulkanFboCache.h"
 #include "VulkanHandles.h"
@@ -34,10 +33,9 @@ namespace filament::backend {

 namespace {

-inline void blitFast(VulkanCommandBuffer* commands, VkImageAspectFlags aspect, VkFilter filter,
+inline void blitFast(const VkCommandBuffer cmdbuffer, VkImageAspectFlags aspect, VkFilter filter,
        VulkanAttachment src, VulkanAttachment dst,
        const VkOffset3D srcRect[2], const VkOffset3D dstRect[2]) {
-    VkCommandBuffer const cmdbuf = commands->buffer();
    if constexpr (FVK_ENABLED(FVK_DEBUG_BLITTER)) {
        FVK_LOGD << "Fast blit from=" << src.texture->getVkImage() << ",level=" << (int) src.level
                      << " layout=" << src.getLayout()
@@ -51,8 +49,8 @@ inline void blitFast(VulkanCommandBuffer* commands, VkImageAspectFlags aspect, V
    VulkanLayout oldSrcLayout = src.getLayout();
    VulkanLayout oldDstLayout = dst.getLayout();

-    src.texture->transitionLayout(commands, srcRange, VulkanLayout::TRANSFER_SRC);
-    dst.texture->transitionLayout(commands, dstRange, VulkanLayout::TRANSFER_DST);
+    src.texture->transitionLayout(cmdbuffer, srcRange, VulkanLayout::TRANSFER_SRC);
+    dst.texture->transitionLayout(cmdbuffer, dstRange, VulkanLayout::TRANSFER_DST);

    const VkImageBlit blitRegions[1] = {{
            .srcSubresource = { aspect, src.level, src.layer, 1 },
@@ -60,7 +58,7 @@ inline void blitFast(VulkanCommandBuffer* commands, VkImageAspectFlags aspect, V
            .dstSubresource = { aspect, dst.level, dst.layer, 1 },
            .dstOffsets = { dstRect[0], dstRect[1] },
    }};
-    vkCmdBlitImage(cmdbuf,
+    vkCmdBlitImage(cmdbuffer,
            src.getImage(), imgutil::getVkLayout(VulkanLayout::TRANSFER_SRC),
            dst.getImage(), imgutil::getVkLayout(VulkanLayout::TRANSFER_DST),
            1, blitRegions, filter);
@@ -71,13 +69,12 @@ inline void blitFast(VulkanCommandBuffer* commands, VkImageAspectFlags aspect, V
    if (oldDstLayout == VulkanLayout::UNDEFINED) {
        oldDstLayout = imgutil::getDefaultLayout(dst.texture->usage);
    }
-    src.texture->transitionLayout(commands, srcRange, oldSrcLayout);
-    dst.texture->transitionLayout(commands, dstRange, oldDstLayout);
+    src.texture->transitionLayout(cmdbuffer, srcRange, oldSrcLayout);
+    dst.texture->transitionLayout(cmdbuffer, dstRange, oldDstLayout);
 }

-inline void resolveFast(VulkanCommandBuffer* commands, VkImageAspectFlags aspect,
+inline void resolveFast(const VkCommandBuffer cmdbuffer, VkImageAspectFlags aspect,
        VulkanAttachment src, VulkanAttachment dst) {
-    VkCommandBuffer const cmdbuffer = commands->buffer();
    if constexpr (FVK_ENABLED(FVK_DEBUG_BLITTER)) {
        FVK_LOGD << "Fast blit from=" << src.texture->getVkImage() << ",level=" << (int) src.level
                      << " layout=" << src.getLayout()
@@ -91,8 +88,8 @@ inline void resolveFast(VulkanCommandBuffer* commands, VkImageAspectFlags aspect
    VulkanLayout oldSrcLayout = src.getLayout();
    VulkanLayout oldDstLayout = dst.getLayout();

-    src.texture->transitionLayout(commands, srcRange, VulkanLayout::TRANSFER_SRC);
-    dst.texture->transitionLayout(commands, dstRange, VulkanLayout::TRANSFER_DST);
+    src.texture->transitionLayout(cmdbuffer, srcRange, VulkanLayout::TRANSFER_SRC);
+    dst.texture->transitionLayout(cmdbuffer, dstRange, VulkanLayout::TRANSFER_DST);

    assert_invariant(
            aspect != VK_IMAGE_ASPECT_DEPTH_BIT && "Resolve with depth is not yet supported.");
@@ -114,8 +111,8 @@ inline void resolveFast(VulkanCommandBuffer* commands, VkImageAspectFlags aspect
    if (oldDstLayout == VulkanLayout::UNDEFINED) {
        oldDstLayout = imgutil::getDefaultLayout(dst.texture->usage);
    }
-    src.texture->transitionLayout(commands, srcRange, oldSrcLayout);
-    dst.texture->transitionLayout(commands, dstRange, oldDstLayout);
+    src.texture->transitionLayout(cmdbuffer, srcRange, oldSrcLayout);
+    dst.texture->transitionLayout(cmdbuffer, dstRange, oldDstLayout);
 }

 struct BlitterUniforms {
@@ -152,9 +149,10 @@ void VulkanBlitter::resolve(VulkanAttachment dst, VulkanAttachment src) {
 #endif

    VulkanCommandBuffer& commands = mCommands->get();
+    VkCommandBuffer const cmdbuffer = commands.buffer();
    commands.acquire(src.texture);
    commands.acquire(dst.texture);
-    resolveFast(&commands, aspect, src, dst);
+    resolveFast(cmdbuffer, aspect, src, dst);
 }

 void VulkanBlitter::blit(VkFilter filter,
@@ -177,9 +175,10 @@ void VulkanBlitter::blit(VkFilter filter,
    // src and dst should have the same aspect here
    VkImageAspectFlags const aspect = src.texture->getImageAspect();
    VulkanCommandBuffer& commands = mCommands->get();
+    VkCommandBuffer const cmdbuffer = commands.buffer();
    commands.acquire(src.texture);
    commands.acquire(dst.texture);
-    blitFast(&commands, aspect, filter, src, dst, srcRectPair, dstRectPair);
+    blitFast(cmdbuffer, aspect, filter, src, dst, srcRectPair, dstRectPair);
 }

 void VulkanBlitter::terminate() noexcept {
--- a/filament/backend/src/vulkan/VulkanCommands.cpp
+++ b/filament/backend/src/vulkan/VulkanCommands.cpp
@@ -297,11 +297,11 @@ bool VulkanCommands::flush() {
 #endif

    auto& cmdfence = currentbuf->fence;
-    UTILS_UNUSED_IN_RELEASE VkResult result = VK_SUCCESS;
-    {
-        auto scope = cmdfence->setValue(VK_NOT_READY);
-        result = vkQueueSubmit(mQueue, 1, &submitInfo, cmdfence->getFence());
-    }
+    std::unique_lock<utils::Mutex> lock(cmdfence->mutex);
+    cmdfence->status.store(VK_NOT_READY);
+    UTILS_UNUSED_IN_RELEASE VkResult result = vkQueueSubmit(mQueue, 1, &submitInfo, cmdfence->fence);
+    cmdfence->condition.notify_all();
+    lock.unlock();

 #if FVK_ENABLED(FVK_DEBUG_COMMAND_BUFFER)
    if (result != VK_SUCCESS) {
@@ -340,7 +340,7 @@ void VulkanCommands::wait() {
        auto wrapper = mStorage[i].get();
        if (wrapper->buffer() != VK_NULL_HANDLE
                && mCurrentCommandBufferIndex != static_cast<int8_t>(i)) {
-            fences[count++] = wrapper->fence->getFence();
+            fences[count++] = wrapper->fence->fence;
        }
    }
    if (count > 0) {
@@ -361,13 +361,12 @@ void VulkanCommands::gc() {
        if (wrapper->buffer() == VK_NULL_HANDLE) {
            continue;
        }
-        auto const vkfence = wrapper->fence->getFence();
-        VkResult const result = vkGetFenceStatus(mDevice, vkfence);
+        VkResult const result = vkGetFenceStatus(mDevice, wrapper->fence->fence);
        if (result != VK_SUCCESS) {
            continue;
        }
-        fences[count++] = vkfence;
-        wrapper->fence->setValue(VK_SUCCESS);
+        fences[count++] = wrapper->fence->fence;
+        wrapper->fence->status.store(VK_SUCCESS);
        wrapper->reset();
        mAvailableBufferCount++;
    }
@@ -384,9 +383,9 @@ void VulkanCommands::updateFences() {
        if (wrapper->buffer() != VK_NULL_HANDLE) {
            VulkanCmdFence* fence = wrapper->fence.get();
            if (fence) {
-                VkResult status = vkGetFenceStatus(mDevice, fence->getFence());
+                VkResult status = vkGetFenceStatus(mDevice, fence->fence);
                // This is either VK_SUCCESS, VK_NOT_READY, or VK_ERROR_DEVICE_LOST.
-                fence->setValue(status);
+                fence->status.store(status, std::memory_order_relaxed);
            }
        }
    }
--- a/filament/backend/src/vulkan/VulkanCommands.h
+++ b/filament/backend/src/vulkan/VulkanCommands.h
@@ -61,40 +61,8 @@ private:

 // Wrapper to enable use of shared_ptr for implementing shared ownership of low-level Vulkan fences.
 struct VulkanCmdFence {
-    struct SetValueScope {
-    public:
-        ~SetValueScope() {
-            mHolder->mutex.unlock();
-            mHolder->condition.notify_all();
-        }
-
-    private:
-        SetValueScope(VulkanCmdFence* fenceHolder, VkResult result) :
-            mHolder(fenceHolder) {
-            mHolder->mutex.lock();
-            mHolder->status.store(result);
-        }
-        VulkanCmdFence* mHolder;
-        friend struct VulkanCmdFence;
-    };
-
    VulkanCmdFence(VkFence ifence);
    ~VulkanCmdFence() = default;
-
-    SetValueScope setValue(VkResult value) {
-        return {this, value};
-    }
-
-    VkFence& getFence() {
-        return fence;
-    }
-
-    VkResult getStatus() {
-        std::unique_lock<utils::Mutex> lock(mutex);
-        return status.load(std::memory_order_acquire);
-    }
-
-private:
    VkFence fence;
    utils::Condition condition;
    utils::Mutex mutex;
--- a/filament/backend/src/vulkan/VulkanContext.cpp
+++ b/filament/backend/src/vulkan/VulkanContext.cpp
@@ -59,11 +59,7 @@ VkExtent2D VulkanAttachment::getExtent2D() const {

 VkImageView VulkanAttachment::getImageView() {
    assert_invariant(texture);
-    VkImageSubresourceRange range = getSubresourceRange();
-    if (range.layerCount > 1) {
-        return texture->getMultiviewAttachmentView(range);
-    }
-    return texture->getAttachmentView(range);
+    return texture->getAttachmentView(getSubresourceRange());
 }

 bool VulkanAttachment::isDepth() const {
@@ -77,7 +73,7 @@ VkImageSubresourceRange VulkanAttachment::getSubresourceRange() const {
            .baseMipLevel = uint32_t(level),
            .levelCount = 1,
            .baseArrayLayer = uint32_t(layer),
-            .layerCount = layerCount,
+            .layerCount = 1,
    };
 }

--- a/filament/backend/src/vulkan/VulkanContext.h
+++ b/filament/backend/src/vulkan/VulkanContext.h
@@ -43,8 +43,6 @@ struct VulkanCommandBuffer;
 struct VulkanAttachment {
    VulkanTexture* texture = nullptr;
    uint8_t level = 0;
-    uint8_t baseViewIndex = 0;
-    uint8_t layerCount = 1;
    uint16_t layer = 0;

    bool isDepth() const;
@@ -125,10 +123,6 @@ public:
        return mPhysicalDeviceFeatures.imageCubeArray == VK_TRUE;
    }

-    inline bool isDepthClampSupported() const noexcept {
-        return mPhysicalDeviceFeatures.depthClamp == VK_TRUE;
-    }
-
    inline bool isDebugMarkersSupported() const noexcept {
        return mDebugMarkersSupported;
    }
--- a/filament/backend/src/vulkan/VulkanDriver.cpp
+++ b/filament/backend/src/vulkan/VulkanDriver.cpp
@@ -90,9 +90,9 @@ VmaAllocator createAllocator(VkInstance instance, VkPhysicalDevice physicalDevic

 VulkanTexture* createEmptyTexture(VkDevice device, VkPhysicalDevice physicalDevice,
        VulkanContext const& context, VmaAllocator allocator, VulkanCommands* commands,
-        VulkanResourceAllocator* handleAllocator, VulkanStagePool& stagePool) {
+        VulkanStagePool& stagePool) {
    VulkanTexture* emptyTexture = new VulkanTexture(device, physicalDevice, context, allocator,
-            commands, handleAllocator, SamplerType::SAMPLER_2D, 1, TextureFormat::RGBA8, 1, 1, 1, 1,
+            commands, SamplerType::SAMPLER_2D, 1, TextureFormat::RGBA8, 1, 1, 1, 1,
            TextureUsage::DEFAULT | TextureUsage::COLOR_ATTACHMENT | TextureUsage::SUBPASS_INPUT,
            stagePool, true /* heap allocated */);
    uint32_t black = 0;
@@ -149,7 +149,6 @@ VKAPI_ATTR VkBool32 VKAPI_CALL debugUtilsCallback(VkDebugUtilsMessageSeverityFla
 }
 #endif // FVK_EANBLED(FVK_DEBUG_DEBUG_UTILS)

-
 }// anonymous namespace

 #if FVK_ENABLED(FVK_DEBUG_DEBUG_UTILS)
@@ -257,11 +256,15 @@ VulkanDriver::VulkanDriver(VulkanPlatform* platform, VulkanContext const& contex
    mTimestamps = std::make_unique<VulkanTimestamps>(mPlatform->getDevice());

    mEmptyTexture = createEmptyTexture(mPlatform->getDevice(), mPlatform->getPhysicalDevice(),
-            mContext, mAllocator, &mCommands, &mResourceAllocator, mStagePool);
+            mContext, mAllocator, &mCommands, mStagePool);
    mEmptyBufferObject = createEmptyBufferObject(mAllocator, mStagePool, &mCommands);

    mDescriptorSetManager.setPlaceHolders(mSamplerCache.getSampler({}), mEmptyTexture,
            mEmptyBufferObject);
+
+    mGetPipelineFunction = [this](VulkanDescriptorSetLayoutList const& layouts, VulkanProgram* program) {
+        return mPipelineLayoutCache.getLayout(layouts, program);
+    };
 }

 VulkanDriver::~VulkanDriver() noexcept = default;
@@ -384,6 +387,7 @@ void VulkanDriver::collectGarbage() {
    mStagePool.gc();
    mFramebufferCache.gc();
    mPipelineCache.gc();
+    mDescriptorSetManager.gc();

 #if FVK_ENABLED(FVK_DEBUG_RESOURCE_LEAK)
    mResourceAllocator.print();
@@ -418,36 +422,6 @@ void VulkanDriver::endFrame(uint32_t frameId) {
    FVK_SYSTRACE_END();
 }

-void VulkanDriver::updateDescriptorSetBuffer(
-        backend::DescriptorSetHandle dsh,
-        backend::descriptor_binding_t binding,
-        backend::BufferObjectHandle boh,
-        uint32_t offset,
-        uint32_t size) {
-    VulkanDescriptorSet* set = mResourceAllocator.handle_cast<VulkanDescriptorSet*>(dsh);
-    VulkanBufferObject* obj = mResourceAllocator.handle_cast<VulkanBufferObject*>(boh);
-    mDescriptorSetManager.updateBuffer(set, binding, obj, offset, size);
-}
-
-void VulkanDriver::updateDescriptorSetTexture(
-        backend::DescriptorSetHandle dsh,
-        backend::descriptor_binding_t binding,
-        backend::TextureHandle th,
-        SamplerParams params) {
-    VulkanDescriptorSet* set = mResourceAllocator.handle_cast<VulkanDescriptorSet*>(dsh);
-    VulkanTexture* texture = mResourceAllocator.handle_cast<VulkanTexture*>(th);
-
-    // We need to make sure the initial layout transition has been completed before we can write
-    // the sampler descriptor. We flush and wait until the transition has been completed.
-    if (!texture->transitionReady()) {
-        mCommands.flush();
-        mCommands.wait();
-    }
-
-    VkSampler const vksampler = mSamplerCache.getSampler(params);
-    mDescriptorSetManager.updateSampler(set, binding, texture, vksampler);
-}
-
 void VulkanDriver::flush(int) {
    FVK_SYSTRACE_CONTEXT();
    FVK_SYSTRACE_START("flush");
@@ -466,6 +440,12 @@ void VulkanDriver::finish(int dummy) {
    FVK_SYSTRACE_END();
 }

+void VulkanDriver::createSamplerGroupR(Handle<HwSamplerGroup> sbh, uint32_t count,
+        utils::FixedSizeString<32> debugName) {
+    auto sg = mResourceAllocator.construct<VulkanSamplerGroup>(sbh, count);
+    mResourceManager.acquire(sg);
+}
+
 void VulkanDriver::createRenderPrimitiveR(Handle<HwRenderPrimitive> rph,
        Handle<HwVertexBuffer> vbh, Handle<HwIndexBuffer> ibh,
        PrimitiveType pt) {
@@ -548,56 +528,23 @@ void VulkanDriver::createTextureR(Handle<HwTexture> th, SamplerType target, uint
        TextureFormat format, uint8_t samples, uint32_t w, uint32_t h, uint32_t depth,
        TextureUsage usage) {
    auto vktexture = mResourceAllocator.construct<VulkanTexture>(th, mPlatform->getDevice(),
-            mPlatform->getPhysicalDevice(), mContext, mAllocator, &mCommands, &mResourceAllocator,
-            target, levels,
+            mPlatform->getPhysicalDevice(), mContext, mAllocator, &mCommands, target, levels,
            format, samples, w, h, depth, usage, mStagePool);
    mResourceManager.acquire(vktexture);
 }

-//void VulkanDriver::createTextureSwizzledR(Handle<HwTexture> th, SamplerType target, uint8_t levels,
-//        TextureFormat format, uint8_t samples, uint32_t w, uint32_t h, uint32_t depth,
-//        TextureUsage usage,
-//        TextureSwizzle r, TextureSwizzle g, TextureSwizzle b, TextureSwizzle a) {
-//    TextureSwizzle swizzleArray[] = {r, g, b, a};
-//    const VkComponentMapping swizzleMap = getSwizzleMap(swizzleArray);
-//    auto vktexture = mResourceAllocator.construct<VulkanTexture>(th, mPlatform->getDevice(),
-//            mPlatform->getPhysicalDevice(), mContext, mAllocator, &mCommands, &mResourceAllocator,
-//            target, levels, format, samples, w, h, depth, usage, mStagePool,
-//            false /*heap allocated */, swizzleMap);
-//    mResourceManager.acquire(vktexture);
-//}
-
-void VulkanDriver::createTextureViewR(Handle<HwTexture> th, Handle<HwTexture> srch,
-        uint8_t baseLevel, uint8_t levelCount) {
-    VulkanTexture const* src = mResourceAllocator.handle_cast<VulkanTexture const*>(srch);
+void VulkanDriver::createTextureSwizzledR(Handle<HwTexture> th, SamplerType target, uint8_t levels,
+        TextureFormat format, uint8_t samples, uint32_t w, uint32_t h, uint32_t depth,
+        TextureUsage usage,
+        TextureSwizzle r, TextureSwizzle g, TextureSwizzle b, TextureSwizzle a) {
+    TextureSwizzle swizzleArray[] = {r, g, b, a};
+    const VkComponentMapping swizzleMap = getSwizzleMap(swizzleArray);
    auto vktexture = mResourceAllocator.construct<VulkanTexture>(th, mPlatform->getDevice(),
-            mPlatform->getPhysicalDevice(), mContext, mAllocator, &mCommands, &mResourceAllocator,
-            src, baseLevel, levelCount);
+            mPlatform->getPhysicalDevice(), mContext, mAllocator, &mCommands, target, levels,
+            format, samples, w, h, depth, usage, mStagePool, false /*heap allocated */, swizzleMap);
    mResourceManager.acquire(vktexture);
 }

-void VulkanDriver::createTextureViewSwizzleR(Handle<HwTexture> th, Handle<HwTexture> srch,
-        backend::TextureSwizzle r, backend::TextureSwizzle g, backend::TextureSwizzle b,
-        backend::TextureSwizzle a) {
-    TextureSwizzle const swizzleArray[] = {r, g, b, a};
-    VkComponentMapping const swizzle = getSwizzleMap(swizzleArray);
-
-    VulkanTexture const* src = mResourceAllocator.handle_cast<VulkanTexture const*>(srch);
-    auto vktexture = mResourceAllocator.construct<VulkanTexture>(th, mPlatform->getDevice(),
-            mPlatform->getPhysicalDevice(), mContext, mAllocator, &mCommands, &mResourceAllocator,
-            src, swizzle);
-    mResourceManager.acquire(vktexture);
-}
-
-void VulkanDriver::createTextureExternalImageR(Handle<HwTexture> th, backend::TextureFormat format,
-        uint32_t width, uint32_t height, backend::TextureUsage usage, void* image) {
-}
-
-void VulkanDriver::createTextureExternalImagePlaneR(Handle<HwTexture> th,
-        backend::TextureFormat format, uint32_t width, uint32_t height, backend::TextureUsage usage,
-        void* image, uint32_t plane) {
-}
-
 void VulkanDriver::importTextureR(Handle<HwTexture> th, intptr_t id,
        SamplerType target, uint8_t levels,
        TextureFormat format, uint8_t samples, uint32_t w, uint32_t h, uint32_t depth,
@@ -624,6 +571,7 @@ void VulkanDriver::destroyProgram(Handle<HwProgram> ph) {
        return;
    }
    auto vkprogram = mResourceAllocator.handle_cast<VulkanProgram*>(ph);
+    mDescriptorSetManager.clearProgram(vkprogram);
    mResourceManager.release(vkprogram);
 }

@@ -647,8 +595,6 @@ void VulkanDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
            colorTargets[i] = {
                .texture = mResourceAllocator.handle_cast<VulkanTexture*>(color[i].handle),
                .level = color[i].level,
-                .baseViewIndex = color[i].baseViewIndex,
-                .layerCount = layerCount,
                .layer = color[i].layer,
            };
            UTILS_UNUSED_IN_RELEASE VkExtent2D extent = colorTargets[i].getExtent2D();
@@ -663,8 +609,6 @@ void VulkanDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
        depthStencil[0] = {
            .texture = mResourceAllocator.handle_cast<VulkanTexture*>(depth.handle),
            .level = depth.level,
-            .baseViewIndex = depth.baseViewIndex,
-            .layerCount = layerCount,
            .layer = depth.layer,
        };
        UTILS_UNUSED_IN_RELEASE VkExtent2D extent = depthStencil[0].getExtent2D();
@@ -677,8 +621,6 @@ void VulkanDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
        depthStencil[1] = {
            .texture = mResourceAllocator.handle_cast<VulkanTexture*>(stencil.handle),
            .level = stencil.level,
-            .baseViewIndex = stencil.baseViewIndex,
-            .layerCount = layerCount,
            .layer = stencil.layer,
        };
        UTILS_UNUSED_IN_RELEASE VkExtent2D extent = depthStencil[1].getExtent2D();
@@ -693,10 +635,9 @@ void VulkanDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
    assert_invariant(tmin == tmax);
    assert_invariant(tmin.x >= width && tmin.y >= height);

-    auto renderTarget = mResourceAllocator.construct<VulkanRenderTarget>(rth,
-            mPlatform->getDevice(), mPlatform->getPhysicalDevice(), mContext, mAllocator,
-            &mCommands, &mResourceAllocator, width, height, samples, colorTargets, depthStencil,
-            mStagePool, layerCount);
+    auto renderTarget = mResourceAllocator.construct<VulkanRenderTarget>(rth, mPlatform->getDevice(),
+            mPlatform->getPhysicalDevice(), mContext, mAllocator, &mCommands, width, height,
+            samples, colorTargets, depthStencil, mStagePool);
    mResourceManager.acquire(renderTarget);
 }

@@ -724,7 +665,7 @@ void VulkanDriver::createSwapChainR(Handle<HwSwapChain> sch, void* nativeWindow,
        flags = flags | ~(backend::SWAP_CHAIN_CONFIG_SRGB_COLORSPACE);
    }
    auto swapChain = mResourceAllocator.construct<VulkanSwapChain>(sch, mPlatform, mContext,
-            mAllocator, &mCommands, &mResourceAllocator, mStagePool, nativeWindow, flags);
+            mAllocator, &mCommands, mStagePool, nativeWindow, flags);
    mResourceManager.acquire(swapChain);
 }

@@ -737,8 +678,7 @@ void VulkanDriver::createSwapChainHeadlessR(Handle<HwSwapChain> sch, uint32_t wi
    }
    assert_invariant(width > 0 && height > 0 && "Vulkan requires non-zero swap chain dimensions.");
    auto swapChain = mResourceAllocator.construct<VulkanSwapChain>(sch, mPlatform, mContext,
-            mAllocator, &mCommands, &mResourceAllocator, mStagePool,
-            nullptr, flags, VkExtent2D{width, height});
+            mAllocator, &mCommands, mStagePool, nullptr, flags, VkExtent2D{width, height});
    mResourceManager.acquire(swapChain);
 }

@@ -746,22 +686,6 @@ void VulkanDriver::createTimerQueryR(Handle<HwTimerQuery> tqh, int) {
    // nothing to do, timer query was constructed in createTimerQueryS
 }

-void VulkanDriver::createDescriptorSetLayoutR(Handle<HwDescriptorSetLayout> dslh,
-        backend::DescriptorSetLayout&& info) {
-    VulkanDescriptorSetLayout* layout = mResourceAllocator.construct<VulkanDescriptorSetLayout>(
-            dslh, mPlatform->getDevice(), info);
-    mResourceManager.acquire(layout);
-}
-
-void VulkanDriver::createDescriptorSetR(Handle<HwDescriptorSet> dsh,
-        Handle<HwDescriptorSetLayout> dslh) {
-    auto layout = mResourceAllocator.handle_cast<VulkanDescriptorSetLayout*>(dslh);
-    mDescriptorSetManager.createSet(dsh, layout);
-
-    auto set = mResourceAllocator.handle_cast<VulkanDescriptorSet*>(dsh);
-    mResourceManager.acquire(set);
-}
-
 Handle<HwVertexBufferInfo> VulkanDriver::createVertexBufferInfoS() noexcept {
    return mResourceAllocator.allocHandle<VulkanVertexBufferInfo>();
 }
@@ -782,19 +706,7 @@ Handle<HwTexture> VulkanDriver::createTextureS() noexcept {
    return mResourceAllocator.allocHandle<VulkanTexture>();
 }

-Handle<HwTexture> VulkanDriver::createTextureViewS() noexcept {
-    return mResourceAllocator.allocHandle<VulkanTexture>();
-}
-
-Handle<HwTexture> VulkanDriver::createTextureViewSwizzleS() noexcept {
-    return mResourceAllocator.allocHandle<VulkanTexture>();
-}
-
-Handle<HwTexture> VulkanDriver::createTextureExternalImageS() noexcept {
-    return mResourceAllocator.allocHandle<VulkanTexture>();
-}
-
-Handle<HwTexture> VulkanDriver::createTextureExternalImagePlaneS() noexcept {
+Handle<HwTexture> VulkanDriver::createTextureSwizzledS() noexcept {
    return mResourceAllocator.allocHandle<VulkanTexture>();
 }

@@ -802,6 +714,10 @@ Handle<HwTexture> VulkanDriver::importTextureS() noexcept {
    return mResourceAllocator.allocHandle<VulkanTexture>();
 }

+Handle<HwSamplerGroup> VulkanDriver::createSamplerGroupS() noexcept {
+    return mResourceAllocator.allocHandle<VulkanSamplerGroup>();
+}
+
 Handle<HwRenderPrimitive> VulkanDriver::createRenderPrimitiveS() noexcept {
    return mResourceAllocator.allocHandle<VulkanRenderPrimitive>();
 }
@@ -840,12 +756,21 @@ Handle<HwTimerQuery> VulkanDriver::createTimerQueryS() noexcept {
    return tqh;
 }

-Handle<HwDescriptorSetLayout> VulkanDriver::createDescriptorSetLayoutS() noexcept {
-    return mResourceAllocator.allocHandle<VulkanDescriptorSetLayout>();
-}
-
-Handle<HwDescriptorSet> VulkanDriver::createDescriptorSetS() noexcept {
-    return mResourceAllocator.allocHandle<VulkanDescriptorSet>();
+void VulkanDriver::destroySamplerGroup(Handle<HwSamplerGroup> sbh) {
+    if (!sbh) {
+        return;
+    }
+    // Unlike most of the other "Hw" handles, the sampler buffer is an abstract concept and does
+    // not map to any Vulkan objects. To handle destruction, the only thing we need to do is
+    // ensure that the next draw call doesn't try to access a zombie sampler buffer. Therefore,
+    // simply replace all weak references with null.
+    auto* hwsb = mResourceAllocator.handle_cast<VulkanSamplerGroup*>(sbh);
+    for (auto& binding : mSamplerBindings) {
+        if (binding == hwsb) {
+            binding = nullptr;
+        }
+    }
+    mResourceManager.release(hwsb);
 }

 void VulkanDriver::destroySwapChain(Handle<HwSwapChain> sch) {
@@ -870,17 +795,6 @@ void VulkanDriver::destroyTimerQuery(Handle<HwTimerQuery> tqh) {
    mThreadSafeResourceManager.release(vtq);
 }

-void VulkanDriver::destroyDescriptorSetLayout(Handle<HwDescriptorSetLayout> dslh) {
-    VulkanDescriptorSetLayout* layout = mResourceAllocator.handle_cast<VulkanDescriptorSetLayout*>(dslh);
-    mResourceManager.release(layout);
-}
-
-void VulkanDriver::destroyDescriptorSet(Handle<HwDescriptorSet> dsh) {
-    mDescriptorSetManager.destroySet(dsh);
-    VulkanDescriptorSet* set = mResourceAllocator.handle_cast<VulkanDescriptorSet*>(dsh);
-    mResourceManager.release(set);
-}
-
 Handle<HwStream> VulkanDriver::createStreamNative(void* nativeStream) {
    return {};
 }
@@ -918,7 +832,8 @@ FenceStatus VulkanDriver::getFenceStatus(Handle<HwFence> fh) {

    // Internally we use the VK_INCOMPLETE status to mean "not yet submitted".
    // When this fence gets submitted, its status changes to VK_NOT_READY.
-    if (cmdfence->getStatus() == VK_SUCCESS) {
+    std::unique_lock<utils::Mutex> lock(cmdfence->mutex);
+    if (cmdfence->status.load() == VK_SUCCESS) {
        return FenceStatus::CONDITION_SATISFIED;
    }

@@ -969,9 +884,7 @@ bool VulkanDriver::isRenderTargetFormatSupported(TextureFormat format) {
 }

 bool VulkanDriver::isFrameBufferFetchSupported() {
-    // TODO: we must fix this before landing descriptor set change.  Otherwise, the scuba tests will fail.
-    //return true;
-    return false;
+    return true;
 }

 bool VulkanDriver::isFrameBufferFetchMultiSampleSupported() {
@@ -1025,10 +938,6 @@ bool VulkanDriver::isProtectedTexturesSupported() {
    return false;
 }

-bool VulkanDriver::isDepthClampSupported() {
-    return mContext.isDepthClampSupported();
-}
-
 bool VulkanDriver::isWorkaroundNeeded(Workaround workaround) {
    switch (workaround) {
        case Workaround::SPLIT_EASU: {
@@ -1159,6 +1068,10 @@ void VulkanDriver::resetBufferObject(Handle<HwBufferObject> boh) {
    // This is only useful if updateBufferObjectUnsynchronized() is implemented unsynchronizedly.
 }

+void VulkanDriver::setMinMaxLevels(Handle<HwTexture> th, uint32_t minLevel, uint32_t maxLevel) {
+    mResourceAllocator.handle_cast<VulkanTexture*>(th)->setPrimaryRange(minLevel, maxLevel);
+}
+
 void VulkanDriver::update3DImage(Handle<HwTexture> th, uint32_t level, uint32_t xoffset,
        uint32_t yoffset, uint32_t zoffset, uint32_t width, uint32_t height, uint32_t depth,
        PixelBufferDescriptor&& data) {
@@ -1244,6 +1157,23 @@ void VulkanDriver::generateMipmaps(Handle<HwTexture> th) {
        srcw = dstw;
        srch = dsth;
    } while ((srcw > 1 || srch > 1) && level < t->levels);
+    t->setPrimaryRange(0, t->levels - 1);
+}
+
+void VulkanDriver::updateSamplerGroup(Handle<HwSamplerGroup> sbh,
+        BufferDescriptor&& data) {
+    auto* sb = mResourceAllocator.handle_cast<VulkanSamplerGroup*>(sbh);
+
+    // FIXME: we shouldn't be using SamplerGroup here, instead the backend should create
+    //        a descriptor or any internal data-structure that represents the textures/samplers.
+    //        It's preferable to do as much work as possible here.
+    //        Here, we emulate the older backend API by re-creating a SamplerGroup from the
+    //        passed data.
+    SamplerGroup samplerGroup(data.size / sizeof(SamplerDescriptor));
+    memcpy(samplerGroup.data(), data.buffer, data.size);
+    *sb->sb = std::move(samplerGroup);
+
+    scheduleDestroy(std::move(data));
 }

 void VulkanDriver::compilePrograms(CompilerPriorityQueue priority,
@@ -1258,7 +1188,7 @@ void VulkanDriver::beginRenderPass(Handle<HwRenderTarget> rth, const RenderPassP
    FVK_SYSTRACE_START("beginRenderPass");

    VulkanRenderTarget* const rt = mResourceAllocator.handle_cast<VulkanRenderTarget*>(rth);
-    VkExtent2D const extent = rt->getExtent();
+    const VkExtent2D extent = rt->getExtent();
    assert_invariant(rt == mDefaultRenderTarget || extent.width > 0 && extent.height > 0);

    // Filament has the expectation that the contents of the swap chain are not preserved on the
@@ -1288,6 +1218,36 @@ void VulkanDriver::beginRenderPass(Handle<HwRenderTarget> rth, const RenderPassP
    // the non-sampling case.
    VulkanCommandBuffer& commands = mCommands.get();
    VkCommandBuffer const cmdbuffer = commands.buffer();
+
+    UTILS_NOUNROLL
+    for (uint8_t samplerGroupIdx = 0; samplerGroupIdx < Program::SAMPLER_BINDING_COUNT;
+            samplerGroupIdx++) {
+        VulkanSamplerGroup* vksb = mSamplerBindings[samplerGroupIdx];
+        if (!vksb) {
+            continue;
+        }
+        SamplerGroup* sb = vksb->sb.get();
+        for (size_t i = 0; i < sb->getSize(); i++) {
+            SamplerDescriptor const* boundSampler = sb->data() + i;
+            if (UTILS_LIKELY(boundSampler->t)) {
+                VulkanTexture* texture
+                        = mResourceAllocator.handle_cast<VulkanTexture*>(boundSampler->t);
+                if (!any(texture->usage & TextureUsage::DEPTH_ATTACHMENT)) {
+                    continue;
+                }
+                if (texture->getPrimaryImageLayout() == VulkanLayout::DEPTH_SAMPLER) {
+                    continue;
+                }
+                commands.acquire(texture);
+
+                // Transition the primary view, which is the sampler's view into the right layout.
+                texture->transitionLayout(cmdbuffer, texture->getPrimaryViewRange(),
+                        VulkanLayout::DEPTH_SAMPLER);
+                break;
+            }
+        }
+    }
+
    VulkanLayout currentDepthLayout = depth.getLayout();

    TargetBufferFlags clearVal = params.flags.clear;
@@ -1300,13 +1260,13 @@ void VulkanDriver::beginRenderPass(Handle<HwRenderTarget> rth, const RenderPassP
        // If the depth attachment texture was previously sampled, then we need to manually
        // transition it to an attachment. This is necessary to also set up a barrier between the
        // previous read and the potentially coming write.
-        depth.texture->transitionLayout(&commands, depth.getSubresourceRange(),
-                VulkanLayout::DEPTH_ATTACHMENT);
-        currentDepthLayout = VulkanLayout::DEPTH_ATTACHMENT;
+        if (currentDepthLayout == VulkanLayout::DEPTH_SAMPLER) {
+            depth.texture->transitionLayout(cmdbuffer, depth.getSubresourceRange(),
+                    VulkanLayout::DEPTH_ATTACHMENT);
+            currentDepthLayout = VulkanLayout::DEPTH_ATTACHMENT;
+        }
    }

-    uint8_t const renderTargetLayerCount = rt->getLayerCount();
-
    // Create the VkRenderPass or fetch it from cache.
    VulkanFboCache::RenderPassKey rpkey = {
        .initialColorLayoutMask = 0,
@@ -1317,17 +1277,20 @@ void VulkanDriver::beginRenderPass(Handle<HwRenderTarget> rth, const RenderPassP
        .discardEnd = discardEndVal,
        .samples = rt->getSamples(),
        .subpassMask = uint8_t(params.subpassMask),
-        .viewCount = renderTargetLayerCount,
    };
    for (int i = 0; i < MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT; i++) {
-        VulkanAttachment const& info = rt->getColor(i);
+        const VulkanAttachment& info = rt->getColor(i);
        if (info.texture) {
-            assert_invariant(info.layerCount == renderTargetLayerCount);
            rpkey.initialColorLayoutMask |= 1 << i;
            rpkey.colorFormat[i] = info.getFormat();
            if (rpkey.samples > 1 && info.texture->samples == 1) {
                rpkey.needsResolveMask |= (1 << i);
            }
+            if (info.texture->getPrimaryImageLayout() != VulkanLayout::COLOR_ATTACHMENT) {
+                ((VulkanTexture*) info.texture)
+                        ->transitionLayout(cmdbuffer, info.getSubresourceRange(),
+                                VulkanLayout::COLOR_ATTACHMENT);
+            }
        } else {
            rpkey.colorFormat[i] = VK_FORMAT_UNDEFINED;
        }
@@ -1346,39 +1309,28 @@ void VulkanDriver::beginRenderPass(Handle<HwRenderTarget> rth, const RenderPassP
    };
    auto& renderPassAttachments = mRenderPassFboInfo.attachments;
    for (int i = 0; i < MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT; i++) {
-        VulkanAttachment& attachment = rt->getColor(i);
-        if (!attachment.texture) {
+        if (!rt->getColor(i).texture) {
            fbkey.color[i] = VK_NULL_HANDLE;
            fbkey.resolve[i] = VK_NULL_HANDLE;
-            continue;
-        }
-
-        if (fbkey.samples == 1) {
-            auto const& range = attachment.getSubresourceRange();
-            attachment.texture->transitionLayout(&commands,
-                    range, VulkanLayout::COLOR_ATTACHMENT);
-            renderPassAttachments.insert(attachment);
-            fbkey.color[i] = attachment.getImageView();
+        } else if (fbkey.samples == 1) {
+            auto& colorAttachment = rt->getColor(i);
+            renderPassAttachments.insert(colorAttachment);
+            fbkey.color[i] = colorAttachment.getImageView();
            fbkey.resolve[i] = VK_NULL_HANDLE;
            assert_invariant(fbkey.color[i]);
        } else {
            auto& msaaColorAttachment = rt->getMsaaColor(i);
-            auto const& msaaRange = attachment.getSubresourceRange();
-            msaaColorAttachment.texture->transitionLayout(&commands,
-                    msaaRange, VulkanLayout::COLOR_ATTACHMENT);
            renderPassAttachments.insert(msaaColorAttachment);

+            auto& colorAttachment = rt->getColor(i);
            fbkey.color[i] = msaaColorAttachment.getImageView();

-            VulkanTexture* texture = attachment.texture;
+            VulkanTexture* texture = colorAttachment.texture;
            if (texture->samples == 1) {
                mRenderPassFboInfo.hasColorResolve = true;

-                auto const& range = attachment.getSubresourceRange();
-                attachment.texture->transitionLayout(&commands,
-                        range, VulkanLayout::COLOR_ATTACHMENT);
-                renderPassAttachments.insert(attachment);
-                fbkey.resolve[i] = attachment.getImageView();
+                renderPassAttachments.insert(colorAttachment);
+                fbkey.resolve[i] = colorAttachment.getImageView();
                assert_invariant(fbkey.resolve[i]);
            }
            assert_invariant(fbkey.color[i]);
@@ -1496,27 +1448,57 @@ void VulkanDriver::endRenderPass(int) {
    assert_invariant(rt);

    // Since we might soon be sampling from the render target that we just wrote to, we need a
-    // pipeline barrier between framebuffer writes and shader reads.
+    // pipeline barrier between framebuffer writes and shader reads. This is a memory barrier rather
+    // than an image barrier. If we were to use image barriers here, we would potentially need to
+    // issue several of them when considering MRT. This would be very complex to set up and would
+    // require more state tracking, so we've chosen to use a memory barrier for simplicity and
+    // correctness.
    if (!rt->isSwapChain()) {
-        for (auto& attachment: mRenderPassFboInfo.attachments) {
-            auto const& range = attachment.getSubresourceRange();
+        for (auto const& attachment: mRenderPassFboInfo.attachments) {
            bool const isDepth = attachment.isDepth();
-            auto texture = attachment.texture;
-            if (isDepth) {
-                texture->setLayout(range, VulkanFboCache::FINAL_DEPTH_ATTACHMENT_LAYOUT);
-                if (!texture->transitionLayout(&commands, range, VulkanLayout::DEPTH_SAMPLER)) {
-                    texture->attachmentToSamplerBarrier(&commands, range);
-                }
-            } else {
-                texture->setLayout(range, VulkanFboCache::FINAL_COLOR_ATTACHMENT_LAYOUT);
-                if (!texture->transitionLayout(&commands, range, VulkanLayout::READ_WRITE)) {
-                    texture->attachmentToSamplerBarrier(&commands, range);
-                }
+            VkPipelineStageFlags srcStageMask = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;
+
+            // This is a workaround around a validation issue (might not be an actual driver issue).
+            if (mRenderPassFboInfo.hasColorResolve && !isDepth) {
+                srcStageMask = VK_PIPELINE_STAGE_ALL_GRAPHICS_BIT;
            }
+
+            VkPipelineStageFlags dstStageMask =
+                    VK_PIPELINE_STAGE_VERTEX_SHADER_BIT | VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT;
+            VkAccessFlags srcAccess = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT;
+            VkAccessFlags dstAccess = VK_ACCESS_SHADER_READ_BIT;
+            VulkanLayout layout = VulkanFboCache::FINAL_COLOR_ATTACHMENT_LAYOUT;
+            if (isDepth) {
+                srcAccess = VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_WRITE_BIT;
+                dstAccess = VK_ACCESS_DEPTH_STENCIL_ATTACHMENT_READ_BIT;
+                srcStageMask = VK_PIPELINE_STAGE_LATE_FRAGMENT_TESTS_BIT;
+                dstStageMask = VK_PIPELINE_STAGE_EARLY_FRAGMENT_TESTS_BIT;
+                layout =  VulkanFboCache::FINAL_DEPTH_ATTACHMENT_LAYOUT;
+            }
+
+            auto const vkLayout = imgutil::getVkLayout(layout);
+            auto const& range = attachment.getSubresourceRange();
+            VkImageMemoryBarrier barrier = {
+                .sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER,
+                .pNext = nullptr,
+                .srcAccessMask = srcAccess,
+                .dstAccessMask = dstAccess,
+                .oldLayout = vkLayout,
+                .newLayout = vkLayout,
+                .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                .image = attachment.getImage(),
+                .subresourceRange = range,
+            };
+
+            attachment.texture->setLayout(range, layout);
+            vkCmdPipelineBarrier(cmdbuffer, srcStageMask, dstStageMask, 0, 0, nullptr, 0, nullptr,
+                    1, &barrier);
        }
    }

    mRenderPassFboInfo.clear();
+    mDescriptorSetManager.clearState();
    mCurrentRenderPass.renderTarget = nullptr;
    mCurrentRenderPass.renderPass = VK_NULL_HANDLE;
    FVK_SYSTRACE_END();
@@ -1575,6 +1557,33 @@ void VulkanDriver::commit(Handle<HwSwapChain> sch) {
    FVK_SYSTRACE_END();
 }

+void VulkanDriver::bindUniformBuffer(uint32_t index, Handle<HwBufferObject> boh) {
+    auto* bo = mResourceAllocator.handle_cast<VulkanBufferObject*>(boh);
+    VkDeviceSize const offset = 0;
+    VkDeviceSize const size = VK_WHOLE_SIZE;
+    mDescriptorSetManager.updateBuffer({}, (uint32_t) index, bo, offset, size);
+}
+
+void VulkanDriver::bindBufferRange(BufferObjectBinding bindingType, uint32_t index,
+        Handle<HwBufferObject> boh, uint32_t offset, uint32_t size) {
+
+    assert_invariant(bindingType == BufferObjectBinding::UNIFORM);
+
+    // TODO: implement BufferObjectBinding::SHADER_STORAGE case
+
+    auto* bo = mResourceAllocator.handle_cast<VulkanBufferObject*>(boh);
+    mDescriptorSetManager.updateBuffer({}, (uint32_t) index, bo, offset, size);
+}
+
+void VulkanDriver::unbindBuffer(BufferObjectBinding bindingType, uint32_t index) {
+    mDescriptorSetManager.clearBuffer((uint32_t) index);
+}
+
+void VulkanDriver::bindSamplers(uint32_t index, Handle<HwSamplerGroup> sbh) {
+    auto* hwsb = mResourceAllocator.handle_cast<VulkanSamplerGroup*>(sbh);
+    mSamplerBindings[index] = hwsb;
+}
+
 void VulkanDriver::setPushConstant(backend::ShaderStage stage, uint8_t index,
        backend::PushConstantVariant value) {
    assert_invariant(mBoundPipeline.program && "Expect a program when writing to push constants");
@@ -1583,13 +1592,13 @@ void VulkanDriver::setPushConstant(backend::ShaderStage stage, uint8_t index,
            value);
 }

-void VulkanDriver::insertEventMarker(char const* string) {
+void VulkanDriver::insertEventMarker(char const* string, uint32_t len) {
 #if FVK_ENABLED(FVK_DEBUG_GROUP_MARKERS)
-    mCommands.insertEventMarker(string, strlen(string));
+    mCommands.insertEventMarker(string, len);
 #endif
 }

-void VulkanDriver::pushGroupMarker(char const* string) {
+void VulkanDriver::pushGroupMarker(char const* string, uint32_t) {
    // Turns out all the markers are 0-terminated, so we can just pass it without len.
 #if FVK_ENABLED(FVK_DEBUG_GROUP_MARKERS)
    mCommands.pushGroupMarker(string);
@@ -1775,8 +1784,8 @@ void VulkanDriver::bindPipeline(PipelineState const& pipelineState) {
            *mResourceAllocator.handle_cast<VulkanVertexBufferInfo*>(pipelineState.vertexBufferInfo);

    Handle<HwProgram> programHandle = pipelineState.program;
-    RasterState const& rasterState = pipelineState.rasterState;
-    PolygonOffset const& depthOffset = pipelineState.polygonOffset;
+    RasterState rasterState = pipelineState.rasterState;
+    PolygonOffset depthOffset = pipelineState.polygonOffset;

    auto* program = mResourceAllocator.handle_cast<VulkanProgram*>(programHandle);
    commands->acquire(program);
@@ -1797,7 +1806,6 @@ void VulkanDriver::bindPipeline(PipelineState const& pipelineState) {
        .dstAlphaBlendFactor = getBlendFactor(rasterState.blendFunctionDstAlpha),
        .colorWriteMask = (VkColorComponentFlags) (rasterState.colorWrite ? 0xf : 0x0),
        .rasterizationSamples = rt->getSamples(),
-        .depthClamp = rasterState.depthClamp,
        .colorTargetCount = rt->getColorTargetCount(mCurrentRenderPass),
        .colorBlendOp = rasterState.blendEquationRGB,
        .alphaBlendOp =  rasterState.blendEquationAlpha,
@@ -1820,26 +1828,59 @@ void VulkanDriver::bindPipeline(PipelineState const& pipelineState) {
    mPipelineCache.bindPrimitiveTopology(topology);
    mPipelineCache.bindVertexArray(attribDesc, bufferDesc, vbi.getAttributeCount());

-    auto& setLayouts = pipelineState.pipelineLayout.setLayout;
-    VulkanDescriptorSetLayout::DescriptorSetLayoutArray layoutList;
-    uint8_t layoutCount = 0;
-    std::transform(setLayouts.begin(), setLayouts.end(), layoutList.begin(),
-            [&](Handle<HwDescriptorSetLayout> handle) -> VkDescriptorSetLayout {
-                if (!handle) {
-                    return VK_NULL_HANDLE;
-                }
-                auto layout = mResourceAllocator.handle_cast<VulkanDescriptorSetLayout*>(handle);
-                layoutCount++;
-                return layout->vklayout;
-            });
-    auto pipelineLayout = mPipelineLayoutCache.getLayout(layoutList, program);
+    // Query the program for the mapping from (SamplerGroupBinding,Offset) to (SamplerBinding),
+    // where "SamplerBinding" is the integer in the GLSL, and SamplerGroupBinding is the abstract
+    // Filament concept used to form groups of samplers.

-    constexpr uint8_t descriptorSetMaskTable[4] = {0x1, 0x3, 0x7, 0xF};
+    auto const& bindingToSamplerIndex = program->getBindingToSamplerIndex();
+#if FVK_ENABLED_DEBUG_SAMPLER_NAME
+    auto const& bindingToName = program->getBindingToName();
+#endif

+    for (auto binding: program->getBindings()) {
+        uint16_t const indexPair = bindingToSamplerIndex[binding];
+        if (indexPair == 0xffff) {
+            continue;
+        }
+
+        uint16_t const samplerGroupInd = (indexPair >> 8) & 0xff;
+        uint16_t const samplerInd = (indexPair & 0xff);
+
+        VulkanSamplerGroup* vksb = mSamplerBindings[samplerGroupInd];
+        if (!vksb) {
+            continue;
+        }
+        SamplerDescriptor const* boundSampler = ((SamplerDescriptor*) vksb->sb->data()) + samplerInd;
+
+        if (UTILS_UNLIKELY(!boundSampler->t)) {
+            continue;
+        }
+        VulkanTexture* texture = mResourceAllocator.handle_cast<VulkanTexture*>(boundSampler->t);
+
+        // TODO: can this uninitialized check be checked in a higher layer?
+        // This fallback path is very flaky because the dummy texture might not have
+        // matching characteristics. (e.g. if the missing texture is a 3D texture)
+        if (UTILS_UNLIKELY(texture->getPrimaryImageLayout() == VulkanLayout::UNDEFINED)) {
+#if FVK_ENABLED(FVK_DEBUG_TEXTURE) && FVK_ENABLED_DEBUG_SAMPLER_NAME
+            FVK_LOGW << "Uninitialized texture bound to '" << bindingToName[binding] << "'";
+            FVK_LOGW << " in material '" << program->name.c_str() << "'";
+            FVK_LOGW << " at binding point " << +binding << utils::io::endl;
+#endif
+            texture = mEmptyTexture;
+        }
+
+        VkSampler const vksampler = mSamplerCache.getSampler(boundSampler->s);
+#if FVK_ENABLED_DEBUG_SAMPLER_NAME
+        VulkanDriver::DebugUtils::setName(VK_OBJECT_TYPE_SAMPLER,
+                reinterpret_cast<uint64_t>(vksampler), bindingToName[binding].c_str());
+#endif
+        mDescriptorSetManager.updateSampler({}, binding, texture, vksampler);
+    }
+
+    auto const pipelineLayout = mDescriptorSetManager.bind(commands, program, mGetPipelineFunction);
    mBoundPipeline = {
        .program = program,
        .pipelineLayout = pipelineLayout,
-        .descriptorSetMask = DescriptorSetMask(descriptorSetMaskTable[layoutCount]),
    };

    mPipelineCache.bindLayout(pipelineLayout);
@@ -1882,14 +1923,6 @@ void VulkanDriver::bindRenderPrimitive(Handle<HwRenderPrimitive> rph) {
    FVK_SYSTRACE_END();
 }

-void VulkanDriver::bindDescriptorSet(
-        backend::DescriptorSetHandle dsh,
-        backend::descriptor_set_t setIndex,
-        backend::DescriptorSetOffsetArray&& offsets) {
-    VulkanDescriptorSet* set = mResourceAllocator.handle_cast<VulkanDescriptorSet*>(dsh);
-    mDescriptorSetManager.bind(setIndex, set, std::move(offsets));
-}
-
 void VulkanDriver::draw2(uint32_t indexOffset, uint32_t indexCount, uint32_t instanceCount) {
    FVK_SYSTRACE_CONTEXT();
    FVK_SYSTRACE_START("draw2");
@@ -1897,8 +1930,8 @@ void VulkanDriver::draw2(uint32_t indexOffset, uint32_t indexCount, uint32_t ins
    VulkanCommandBuffer& commands = mCommands.get();
    VkCommandBuffer cmdbuffer = commands.buffer();

-    mDescriptorSetManager.commit(&commands, mBoundPipeline.pipelineLayout,
-            mBoundPipeline.descriptorSetMask);
+    // Bind "dynamic" UBOs if they need to change.
+    mDescriptorSetManager.dynamicBind(&commands, {});

    // Finally, make the actual draw call. TODO: support subranges
    const uint32_t firstIndex = indexOffset;
@@ -1946,7 +1979,7 @@ void VulkanDriver::scissor(Viewport scissorBox) {
            .extent = { uint32_t(r - l), uint32_t(t - b) }
    };

-    VulkanRenderTarget const* rt = mCurrentRenderPass.renderTarget;
+    const VulkanRenderTarget* rt = mCurrentRenderPass.renderTarget;
    rt->transformClientRectToPlatform(&scissor);
    vkCmdSetScissor(cmdbuffer, 0, 1, &scissor);
 }
@@ -1989,10 +2022,6 @@ void VulkanDriver::debugCommandBegin(CommandStream* cmds, bool synchronous, cons
 void VulkanDriver::resetState(int) {
 }

-void VulkanDriver::setDebugTag(HandleBase::HandleId handleId, utils::CString tag) {
-    mResourceAllocator.associateHandle(handleId, std::move(tag));
-}
-
 // explicit instantiation of the Dispatcher
 template class ConcreteDispatcher<VulkanDriver>;

--- a/filament/backend/src/vulkan/VulkanDriver.h
+++ b/filament/backend/src/vulkan/VulkanDriver.h
@@ -159,11 +159,12 @@ private:
    VulkanReadPixels mReadPixels;
    VulkanDescriptorSetManager mDescriptorSetManager;

+    VulkanDescriptorSetManager::GetPipelineLayoutFunction mGetPipelineFunction;
+
    // This is necessary for us to write to push constants after binding a pipeline.
    struct BoundPipeline {
        VulkanProgram* program;
        VkPipelineLayout pipelineLayout;
-        DescriptorSetMask descriptorSetMask;
    };
    BoundPipeline mBoundPipeline = {};
    RenderPassFboBundle mRenderPassFboInfo;
--- a/filament/backend/src/vulkan/VulkanFboCache.cpp
+++ b/filament/backend/src/vulkan/VulkanFboCache.cpp
@@ -43,7 +43,6 @@ bool VulkanFboCache::RenderPassEq::operator()(const RenderPassKey& k1,
    if (k1.samples != k2.samples) return false;
    if (k1.needsResolveMask != k2.needsResolveMask) return false;
    if (k1.subpassMask != k2.subpassMask) return false;
-    if (k1.viewCount != k2.viewCount) return false;
    return true;
 }

@@ -187,25 +186,6 @@ VkRenderPass VulkanFboCache::getRenderPass(RenderPassKey config) noexcept {
        .pDependencies = dependencies
    };

-    VkRenderPassMultiviewCreateInfo multiviewCreateInfo = {};
-    uint32_t const subpassViewMask = (1 << config.viewCount) - 1;
-    // Prepare a view mask array for the maximum number of subpasses. All subpasses have all views
-    // activated.
-    uint32_t const viewMasks[2] = {subpassViewMask, subpassViewMask};
-    if (config.viewCount > 1) {
-        // Fill the multiview create info.
-        multiviewCreateInfo.sType = VK_STRUCTURE_TYPE_RENDER_PASS_MULTIVIEW_CREATE_INFO;
-        multiviewCreateInfo.pNext = nullptr;
-        multiviewCreateInfo.subpassCount = hasSubpasses ? 2u : 1u;
-        multiviewCreateInfo.pViewMasks = viewMasks;
-        multiviewCreateInfo.dependencyCount = 0;
-        multiviewCreateInfo.pViewOffsets = nullptr;
-        multiviewCreateInfo.correlationMaskCount = 1;
-        multiviewCreateInfo.pCorrelationMasks = &subpassViewMask;
-
-        renderPassInfo.pNext = &multiviewCreateInfo;
-    }
-
    int attachmentIndex = 0;

    // Populate the Color Attachments.
--- a/filament/backend/src/vulkan/VulkanFboCache.h
+++ b/filament/backend/src/vulkan/VulkanFboCache.h
@@ -64,7 +64,7 @@ public:
        uint8_t samples; // 1 byte
        uint8_t needsResolveMask; // 1 byte
        uint8_t subpassMask; // 1 byte
-        uint8_t viewCount; // 1 byte
+        uint8_t padding2; // 1 byte
    };
    struct RenderPassVal {
        VkRenderPass handle;
--- a/filament/backend/src/vulkan/VulkanHandles.cpp
+++ b/filament/backend/src/vulkan/VulkanHandles.cpp
@@ -16,11 +16,13 @@

 #include "VulkanHandles.h"

+#include "VulkanDriver.h"
 #include "VulkanConstants.h"
+#include "VulkanDriver.h"
 #include "VulkanMemory.h"
-#include "VulkanResourceAllocator.h"
 #include "VulkanUtility.h"
 #include "spirv/VulkanSpirvUtils.h"
+#include "utils/Log.h"

 #include <backend/platforms/VulkanPlatform.h>

@@ -52,13 +54,54 @@ void clampToFramebuffer(VkRect2D* rect, uint32_t fbWidth, uint32_t fbHeight) {
 }

 template<typename Bitmask>
-inline void fromStageFlags(backend::ShaderStageFlags stage, descriptor_binding_t binding,
-        Bitmask& mask) {
-    if ((bool) (stage & ShaderStageFlags::VERTEX)) {
-        mask.set(binding + getVertexStageShift<Bitmask>());
+static constexpr Bitmask fromStageFlags(ShaderStageFlags2 flags, uint8_t binding) {
+    Bitmask ret = 0;
+    if (flags & ShaderStageFlags2::VERTEX) {
+        ret |= (getVertexStage<Bitmask>() << binding);
    }
-    if ((bool) (stage & ShaderStageFlags::FRAGMENT)) {
-        mask.set(binding + getFragmentStageShift<Bitmask>());
+    if (flags & ShaderStageFlags2::FRAGMENT) {
+        ret |= (getFragmentStage<Bitmask>() << binding);
+    }
+    return ret;
+}
+
+constexpr decltype(VulkanProgram::MAX_SHADER_MODULES) MAX_SHADER_MODULES =
+        VulkanProgram::MAX_SHADER_MODULES;
+
+using LayoutDescriptionList = VulkanProgram::LayoutDescriptionList;
+
+template<typename Bitmask>
+void addDescriptors(Bitmask mask,
+        utils::FixedCapacityVector<DescriptorSetLayoutBinding>& outputList) {
+    constexpr uint8_t MODULE_OFFSET = (sizeof(Bitmask) * 8) / MAX_SHADER_MODULES;
+    for (uint8_t i = 0; i < MODULE_OFFSET; ++i) {
+        bool const hasVertex = (mask & (1ULL << i)) != 0;
+        bool const hasFragment = (mask & (1ULL << (MODULE_OFFSET + i))) != 0;
+        if (!hasVertex && !hasFragment) {
+            continue;
+        }
+
+        DescriptorSetLayoutBinding binding{
+            .binding = i,
+            .flags = DescriptorFlags::NONE,
+            .count = 0,// This is always 0 for now as we pass the size of the UBOs in the Driver API
+                       // instead.
+        };
+        if (hasVertex) {
+            binding.stageFlags = ShaderStageFlags2::VERTEX;
+        }
+        if (hasFragment) {
+            binding.stageFlags = static_cast<ShaderStageFlags2>(
+                    binding.stageFlags | ShaderStageFlags2::FRAGMENT);
+        }
+        if constexpr (std::is_same_v<Bitmask, UniformBufferBitmask>) {
+            binding.type = DescriptorType::UNIFORM_BUFFER;
+        } else if constexpr (std::is_same_v<Bitmask, SamplerBitmask>) {
+            binding.type = DescriptorType::SAMPLER;
+        } else if constexpr (std::is_same_v<Bitmask, InputAttachmentBitmask>) {
+            binding.type = DescriptorType::INPUT_ATTACHMENT;
+        }
+        outputList.push_back(binding);
    }
 }

@@ -80,113 +123,22 @@ inline VkShaderStageFlags getVkStage(backend::ShaderStage stage) {
    }
 }

-inline VkDescriptorSetLayoutCreateInfo getLayoutCreateInfo(DescriptorSetLayout const& layout) {
-    // Note that the following *needs* to be static so that VkDescriptorSetLayoutCreateInfo will not
-    // refer to stack memory.
-    static VkDescriptorSetLayoutBinding toBind[VulkanDescriptorSetLayout::MAX_BINDINGS];
-    uint32_t count = 0;
-
-    for (auto const& binding: layout.bindings) {
-        VkShaderStageFlags stages = 0;
-        VkDescriptorType type;
-
-        if ((binding.stageFlags & ShaderStageFlags::VERTEX) != ShaderStageFlags::NONE) {
-            stages |= VK_SHADER_STAGE_VERTEX_BIT;
-        }
-        if ((binding.stageFlags & ShaderStageFlags::FRAGMENT) != ShaderStageFlags::NONE) {
-            stages |= VK_SHADER_STAGE_FRAGMENT_BIT;
-        }
-        assert_invariant(stages != 0);
-
-        switch (binding.type) {
-            case DescriptorType::UNIFORM_BUFFER: {
-                type = (binding.flags & DescriptorFlags::DYNAMIC_OFFSET) != DescriptorFlags::NONE
-                               ? VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC
-                               : VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER;
-                break;
-            }
-            case DescriptorType::SAMPLER: {
-                type = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
-                break;
-            }
-            case DescriptorType::INPUT_ATTACHMENT: {
-                type = VK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT;
-                break;
-            }
-            case DescriptorType::SHADER_STORAGE_BUFFER:
-                PANIC_POSTCONDITION("Shader storage is not supported.");
-                break;
-        }
-        toBind[count++] = {
-                .binding = binding.binding,
-                .descriptorType = type,
-                .descriptorCount = 1,
-                .stageFlags = stages,
-        };
-    }
-
-    assert_invariant(count != 0 && "Need at least one binding for descriptor set layout.");
-    VkDescriptorSetLayoutCreateInfo dlinfo = {
-            .sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_LAYOUT_CREATE_INFO,
-            .pNext = nullptr,
-            .bindingCount = count,
-            .pBindings = toBind,
-    };
-    return dlinfo;
-}
-
-using BitmaskGroup = VulkanDescriptorSetLayout::Bitmask;
-BitmaskGroup fromBackendLayout(DescriptorSetLayout const& layout) {
-    BitmaskGroup mask;
-    for (auto const& binding: layout.bindings) {
-        switch (binding.type) {
-            case DescriptorType::UNIFORM_BUFFER: {
-                if ((binding.flags & DescriptorFlags::DYNAMIC_OFFSET) != DescriptorFlags::NONE) {
-                    fromStageFlags(binding.stageFlags, binding.binding, mask.dynamicUbo);
-                } else {
-                    fromStageFlags(binding.stageFlags, binding.binding, mask.ubo);
-                }
-                break;
-            }
-            case DescriptorType::SAMPLER: {
-                fromStageFlags(binding.stageFlags, binding.binding, mask.sampler);
-                break;
-            }
-            case DescriptorType::INPUT_ATTACHMENT: {
-                fromStageFlags(binding.stageFlags, binding.binding, mask.inputAttachment);
-                break;
-            }
-            case DescriptorType::SHADER_STORAGE_BUFFER:
-                PANIC_POSTCONDITION("Shader storage is not supported");
-                break;
-        }
-    }
-    return mask;
-}
-
 } // anonymous namespace

+
 VulkanDescriptorSetLayout::VulkanDescriptorSetLayout(VkDevice device,
-        DescriptorSetLayout const& layout)
-    : VulkanResource(VulkanResourceType::DESCRIPTOR_SET_LAYOUT), mDevice(device),
-      vklayout(createDescriptorSetLayout(device, getLayoutCreateInfo(layout))),
-      bitmask(fromBackendLayout(layout)),
-      count(Count::fromLayoutBitmask(bitmask)) {
-}
+        VkDescriptorSetLayoutCreateInfo const& info, Bitmask const& bitmask)
+    : VulkanResource(VulkanResourceType::DESCRIPTOR_SET_LAYOUT),
+      mDevice(device),
+      vklayout(createDescriptorSetLayout(device, info)),
+      bitmask(bitmask),
+      bindings(getBindings(bitmask)),
+      count(Count::fromLayoutBitmask(bitmask)) {}

 VulkanDescriptorSetLayout::~VulkanDescriptorSetLayout() {
    vkDestroyDescriptorSetLayout(mDevice, vklayout, VKALLOC);
 }

-void VulkanDescriptorSet::acquire(VulkanTexture* texture) {
-    mResources.acquire(texture);
-    mTextures[mTextureCount++] = texture;
-}
-
-void VulkanDescriptorSet::acquire(VulkanBufferObject* bufferObject) {
-    mResources.acquire(bufferObject);
-}
-
 PushConstantDescription::PushConstantDescription(backend::Program const& program) noexcept {
    mRangeCount = 0;
    for (auto stage : { ShaderStage::VERTEX, ShaderStage::FRAGMENT, ShaderStage::COMPUTE }) {
@@ -238,11 +190,24 @@ VulkanProgram::VulkanProgram(VkDevice device, Program const& builder) noexcept
      mInfo(new(std::nothrow) PipelineInfo(builder)),
      mDevice(device) {

+    constexpr uint8_t UBO_MODULE_OFFSET = (sizeof(UniformBufferBitmask) * 8) / MAX_SHADER_MODULES;
+    constexpr uint8_t SAMPLER_MODULE_OFFSET = (sizeof(SamplerBitmask) * 8) / MAX_SHADER_MODULES;
+    constexpr uint8_t INPUT_ATTACHMENT_MODULE_OFFSET =
+            (sizeof(InputAttachmentBitmask) * 8) / MAX_SHADER_MODULES;
+
    Program::ShaderSource const& blobs = builder.getShadersSource();
    auto& modules = mInfo->shaders;
+
    auto const& specializationConstants = builder.getSpecializationConstants();
+
    std::vector<uint32_t> shader;

+    // TODO: this will be moved out of the shader as the descriptor set layout will be provided by
+    // Filament instead of parsed from the shaders. See [GDSR] in VulkanDescriptorSetManager.h
+    UniformBufferBitmask uboMask = 0;
+    SamplerBitmask samplerMask = 0;
+    InputAttachmentBitmask inputAttachmentMask = 0;
+
    static_assert(static_cast<ShaderStage>(0) == ShaderStage::VERTEX &&
            static_cast<ShaderStage>(1) == ShaderStage::FRAGMENT &&
            MAX_SHADER_MODULES == 2);
@@ -259,6 +224,12 @@ VulkanProgram::VulkanProgram(VkDevice device, Program const& builder) noexcept
            dataSize = shader.size() * 4;
        }

+        auto const [ubo, sampler, inputAttachment] = getProgramBindings(blob);
+        uboMask |= (static_cast<UniformBufferBitmask>(ubo) << (UBO_MODULE_OFFSET * i));
+        samplerMask |= (static_cast<SamplerBitmask>(sampler) << (SAMPLER_MODULE_OFFSET * i));
+        inputAttachmentMask |= (static_cast<InputAttachmentBitmask>(inputAttachment)
+                                << (INPUT_ATTACHMENT_MODULE_OFFSET * i));
+
        VkShaderModule& module = modules[i];
        VkShaderModuleCreateInfo moduleInfo = {
            .sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO,
@@ -286,6 +257,40 @@ VulkanProgram::VulkanProgram(VkDevice device, Program const& builder) noexcept
 #endif
    }

+    LayoutDescriptionList& layouts = mInfo->layouts;
+    layouts[0].bindings = utils::FixedCapacityVector<DescriptorSetLayoutBinding>::with_capacity(
+            countBits(collapseStages(uboMask)));
+    layouts[1].bindings = utils::FixedCapacityVector<DescriptorSetLayoutBinding>::with_capacity(
+            countBits(collapseStages(samplerMask)));
+    layouts[2].bindings = utils::FixedCapacityVector<DescriptorSetLayoutBinding>::with_capacity(
+            countBits(collapseStages(inputAttachmentMask)));
+
+    addDescriptors(uboMask, layouts[0].bindings);
+    addDescriptors(samplerMask, layouts[1].bindings);
+    addDescriptors(inputAttachmentMask, layouts[2].bindings);
+
+#if FVK_ENABLED_DEBUG_SAMPLER_NAME
+    auto& bindingToName = mInfo->bindingToName;
+#endif
+
+    auto& groupInfo = builder.getSamplerGroupInfo();
+    auto& bindingToSamplerIndex = mInfo->bindingToSamplerIndex;
+    auto& bindings = mInfo->bindings;
+    for (uint8_t groupInd = 0; groupInd < Program::SAMPLER_BINDING_COUNT; groupInd++) {
+        auto const& group = groupInfo[groupInd];
+        auto const& samplers = group.samplers;
+        for (size_t i = 0; i < samplers.size(); ++i) {
+            uint32_t const binding = samplers[i].binding;
+            bindingToSamplerIndex[binding] = (groupInd << 8) | (0xff & i);
+            assert_invariant(bindings.find(binding) == bindings.end());
+            bindings.insert(binding);
+
+#if FVK_ENABLED_DEBUG_SAMPLER_NAME
+            bindingToName[binding] = samplers[i].name.c_str();
+#endif
+        }
+    }
+
 #if FVK_ENABLED(FVK_DEBUG_SHADER_MODULE)
    FVK_LOGD << "Created VulkanProgram " << builder << ", shaders = (" << modules[0]
             << ", " << modules[1] << ")" << utils::io::endl;
@@ -316,15 +321,13 @@ void VulkanRenderTarget::bindToSwapChain(VulkanSwapChain& swapChain) {

 VulkanRenderTarget::VulkanRenderTarget(VkDevice device, VkPhysicalDevice physicalDevice,
        VulkanContext const& context, VmaAllocator allocator, VulkanCommands* commands,
-        VulkanResourceAllocator* handleAllocator,
        uint32_t width, uint32_t height, uint8_t samples,
        VulkanAttachment color[MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT],
-        VulkanAttachment depthStencil[2], VulkanStagePool& stagePool, uint8_t layerCount)
+        VulkanAttachment depthStencil[2], VulkanStagePool& stagePool)
    : HwRenderTarget(width, height),
      VulkanResource(VulkanResourceType::RENDER_TARGET),
      mOffscreen(true),
-      mSamples(samples),
-      mLayerCount(layerCount) {
+      mSamples(samples) {
    for (int index = 0; index < MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT; index++) {
        mColor[index] = color[index];
    }
@@ -350,7 +353,6 @@ VulkanRenderTarget::VulkanRenderTarget(VkDevice device, VkPhysicalDevice physica
            if (UTILS_UNLIKELY(!msTexture)) {
                // TODO: This should be allocated with the ResourceAllocator.
                msTexture = new VulkanTexture(device, physicalDevice, context, allocator, commands,
-                        handleAllocator,
                        texture->target, ((VulkanTexture const*) texture)->levels, texture->format,
                        samples, texture->width, texture->height, texture->depth, texture->usage,
                        stagePool, true /* heap allocated */);
@@ -380,8 +382,7 @@ VulkanRenderTarget::VulkanRenderTarget(VkDevice device, VkPhysicalDevice physica
    VulkanTexture* msTexture = depthTexture->getSidecar();
    if (UTILS_UNLIKELY(!msTexture)) {
        msTexture = new VulkanTexture(device, physicalDevice, context, allocator,
-                commands, handleAllocator,
-                depthTexture->target, msLevel, depthTexture->format, samples,
+                commands, depthTexture->target, msLevel, depthTexture->format, samples,
                depthTexture->width, depthTexture->height, depthTexture->depth, depthTexture->usage,
                stagePool, true /* heap allocated */);
        depthTexture->setSidecar(msTexture);
@@ -533,7 +534,15 @@ bool VulkanTimerQuery::isCompleted() noexcept {
    // timestamp has at least been written into a processed command buffer.

    // This fence indicates that the corresponding buffer has been completed.
-    return mFence && mFence->getStatus() == VK_SUCCESS;
+    if (!mFence) {
+        return false;
+    }
+    VkResult status = mFence->status.load(std::memory_order_relaxed);
+    if (status != VK_SUCCESS) {
+        return false;
+    }
+
+    return true;
 }

 VulkanTimerQuery::~VulkanTimerQuery() = default;
@@ -549,4 +558,35 @@ VulkanRenderPrimitive::VulkanRenderPrimitive(VulkanResourceAllocator* resourceAl
    mResources.acquire(indexBuffer);
 }

+using Bitmask = VulkanDescriptorSetLayout::Bitmask;
+
+Bitmask Bitmask::fromBackendLayout(descset::DescriptorSetLayout const& layout) {
+    Bitmask mask;
+    for (auto const& binding: layout.bindings) {
+        switch (binding.type) {
+            case descset::DescriptorType::UNIFORM_BUFFER: {
+                if (binding.flags == descset::DescriptorFlags::DYNAMIC_OFFSET) {
+                    mask.dynamicUbo |= fromStageFlags<UniformBufferBitmask>(binding.stageFlags,
+                            binding.binding);
+                } else {
+                    mask.ubo |= fromStageFlags<UniformBufferBitmask>(binding.stageFlags,
+                            binding.binding);
+                }
+                break;
+            }
+            case descset::DescriptorType::SAMPLER: {
+                mask.sampler |= fromStageFlags<SamplerBitmask>(binding.stageFlags, binding.binding);
+                break;
+            }
+            case descset::DescriptorType::INPUT_ATTACHMENT: {
+                mask.inputAttachment |=
+                        fromStageFlags<InputAttachmentBitmask>(binding.stageFlags, binding.binding);
+                break;
+            }
+        }
+    }
+    return mask;
+}
+
+
 } // namespace filament::backend
--- a/filament/backend/src/vulkan/VulkanHandles.h
+++ b/filament/backend/src/vulkan/VulkanHandles.h
@@ -29,52 +29,39 @@
 #include <private/backend/SamplerGroup.h>
 #include <backend/Program.h>

-#include <utils/bitset.h>
 #include <utils/FixedCapacityVector.h>
 #include <utils/Mutex.h>
 #include <utils/StructureOfArrays.h>

 namespace filament::backend {

-namespace {
-// Counts the total number of descriptors for both vertex and fragment stages.
-template<typename Bitmask>
-inline uint8_t collapsedCount(Bitmask const& mask) {
-    static_assert(sizeof(mask) <= 64);
-    constexpr uint64_t VERTEX_MASK = (1ULL << getVertexStageShift<Bitmask>()) - 1ULL;
-    constexpr uint64_t FRAGMENT_MASK = (1ULL << getFragmentStageShift<Bitmask>()) - 1ULL;
-    uint64_t val = mask.getValue();
-    val = ((val | VERTEX_MASK) >> getVertexStageShift<Bitmask>()) |
-        ((val | FRAGMENT_MASK) >> getFragmentStageShift<Bitmask>());
-    return (uint8_t) Bitmask(val).count();
-}
-
-} // anonymous namespace
+using namespace descset;

 class VulkanTimestamps;
-struct VulkanBufferObject;

-struct VulkanDescriptorSetLayout : public VulkanResource, HwDescriptorSetLayout {
-    static constexpr uint8_t UNIQUE_DESCRIPTOR_SET_COUNT = 4;
-    static constexpr uint8_t MAX_BINDINGS = 25;
-
-    using DescriptorSetLayoutArray = std::array<VkDescriptorSetLayout,
-            VulkanDescriptorSetLayout::UNIQUE_DESCRIPTOR_SET_COUNT>;
+struct VulkanDescriptorSetLayout : public VulkanResource {
+    static constexpr uint8_t UNIQUE_DESCRIPTOR_SET_COUNT = 3;

    // The bitmask representation of a set layout.
    struct Bitmask {
-        // TODO: better utiltize the space below and use bitset instead.
-        UniformBufferBitmask ubo;         // 8 bytes
-        UniformBufferBitmask dynamicUbo;  // 8 bytes
-        SamplerBitmask sampler;           // 8 bytes
-        InputAttachmentBitmask inputAttachment; // 8 bytes
+        UniformBufferBitmask ubo = 0;         // 4 bytes
+        UniformBufferBitmask dynamicUbo = 0;  // 4 bytes
+        SamplerBitmask sampler = 0;           // 8 bytes
+        InputAttachmentBitmask inputAttachment = 0; // 1 bytes
+
+        // Because we're using this struct as hash key, must make it's 8-bytes aligned, with no
+        // unaccounted bytes.
+        uint8_t padding0 = 0; // 1 bytes
+        uint16_t padding1 = 0;// 2 bytes
+        uint32_t padding2 = 0;// 4 bytes

        bool operator==(Bitmask const& right) const {
            return ubo == right.ubo && dynamicUbo == right.dynamicUbo && sampler == right.sampler &&
                   inputAttachment == right.inputAttachment;
        }
+
+        static Bitmask fromBackendLayout(descset::DescriptorSetLayout const& layout);
    };
-    static_assert(sizeof(Bitmask) == 32);

    // This is a convenience struct to quickly check layout compatibility in terms of descriptor set
    // pools.
@@ -84,10 +71,6 @@ struct VulkanDescriptorSetLayout : public VulkanResource, HwDescriptorSetLayout
        uint32_t sampler = 0;
        uint32_t inputAttachment = 0;

-        inline uint32_t total() const {
-            return ubo + dynamicUbo + sampler + inputAttachment;
-        }
-
        bool operator==(Count const& right) const noexcept {
            return ubo == right.ubo && dynamicUbo == right.dynamicUbo && sampler == right.sampler &&
                   inputAttachment == right.inputAttachment;
@@ -95,10 +78,10 @@ struct VulkanDescriptorSetLayout : public VulkanResource, HwDescriptorSetLayout

        static inline Count fromLayoutBitmask(Bitmask const& mask) {
            return {
-                .ubo = collapsedCount(mask.ubo),
-                .dynamicUbo = collapsedCount(mask.dynamicUbo),
-                .sampler = collapsedCount(mask.sampler),
-                .inputAttachment = collapsedCount(mask.inputAttachment),
+                    .ubo = countBits(collapseStages(mask.ubo)),
+                    .dynamicUbo = countBits(collapseStages(mask.dynamicUbo)),
+                    .sampler = countBits(collapseStages(mask.sampler)),
+                    .inputAttachment = countBits(collapseStages(mask.inputAttachment)),
            };
        }

@@ -114,27 +97,70 @@ struct VulkanDescriptorSetLayout : public VulkanResource, HwDescriptorSetLayout
        }
    };

-    VulkanDescriptorSetLayout(VkDevice device, DescriptorSetLayout const& layout);
+    static_assert(sizeof(Bitmask) % 8 == 0);
+
+    explicit VulkanDescriptorSetLayout(VkDevice device, VkDescriptorSetLayoutCreateInfo const& info,
+            Bitmask const& bitmask);

    ~VulkanDescriptorSetLayout();

    VkDevice const mDevice;
    VkDescriptorSetLayout const vklayout;
    Bitmask const bitmask;
+
+    // This is a convenience struct so that we don't have to iterate through all the bits of the
+    // bitmask (which correspondings to binding indices).
+    struct _Bindings {
+        utils::FixedCapacityVector<uint8_t> const ubo;
+        utils::FixedCapacityVector<uint8_t> const dynamicUbo;
+        utils::FixedCapacityVector<uint8_t> const sampler;
+        utils::FixedCapacityVector<uint8_t> const inputAttachment;
+    } bindings;
+
    Count const count;
+
+private:
+
+    template <typename MaskType>
+    utils::FixedCapacityVector<uint8_t> bits(MaskType mask) {
+        utils::FixedCapacityVector<uint8_t> ret =
+                utils::FixedCapacityVector<uint8_t>::with_capacity(countBits(mask));
+        for (uint8_t i = 0; i < sizeof(mask) * 4; ++i) {
+            if (mask & (1 << i)) {
+                ret.push_back(i);
+            }
+        }
+        return ret;
+    }
+
+    _Bindings getBindings(Bitmask const& bitmask) {
+        auto const uboCollapsed = collapseStages(bitmask.ubo);
+        auto const dynamicUboCollapsed = collapseStages(bitmask.dynamicUbo);
+        auto const samplerCollapsed = collapseStages(bitmask.sampler);
+        auto const inputAttachmentCollapsed = collapseStages(bitmask.inputAttachment);
+        return {
+            bits(uboCollapsed),
+            bits(dynamicUboCollapsed),
+            bits(samplerCollapsed),
+            bits(inputAttachmentCollapsed),
+        };
+    }
 };

-struct VulkanDescriptorSet : public VulkanResource, HwDescriptorSet {
+using VulkanDescriptorSetLayoutList = std::array<Handle<VulkanDescriptorSetLayout>,
+        VulkanDescriptorSetLayout::UNIQUE_DESCRIPTOR_SET_COUNT>;
+
+struct VulkanDescriptorSet : public VulkanResource {
 public:
    // Because we need to recycle descriptor sets not used, we allow for a callback that the "Pool"
    // can use to repackage the vk handle.
    using OnRecycle = std::function<void()>;

-    VulkanDescriptorSet(VulkanResourceAllocator* allocator, VkDescriptorSet rawSet,
-            OnRecycle&& onRecycleFn)
+    VulkanDescriptorSet(VulkanResourceAllocator* allocator,
+            VkDescriptorSet rawSet, OnRecycle&& onRecycleFn)
        : VulkanResource(VulkanResourceType::DESCRIPTOR_SET),
+          resources(allocator),
          vkSet(rawSet),
-          mResources(allocator),
          mOnRecycleFn(std::move(onRecycleFn)) {}

    ~VulkanDescriptorSet() {
@@ -143,25 +169,17 @@ public:
        }
    }

-    void acquire(VulkanTexture* texture);
-
-    void acquire(VulkanBufferObject* texture);
-
-    bool hasTexture(VulkanTexture* texture) {
-        return std::any_of(mTextures.begin(), mTextures.end(),
-                [texture](auto t) { return t == texture; });
-    }
-
    // TODO: maybe change to fixed size for performance.
+    VulkanAcquireOnlyResourceManager resources;
    VkDescriptorSet const vkSet;

 private:
-    std::array<VulkanTexture*, 16> mTextures = { nullptr };
-    uint8_t mTextureCount = 0;
-    VulkanAcquireOnlyResourceManager mResources;
    OnRecycle mOnRecycleFn;
 };

+using VulkanDescriptorSetList = std::array<Handle<VulkanDescriptorSet>,
+        VulkanDescriptorSetLayout::UNIQUE_DESCRIPTOR_SET_COUNT>;
+
 using PushConstantNameArray = utils::FixedCapacityVector<char const*>;
 using PushConstantNameByStage = std::array<PushConstantNameArray, Program::SHADER_TYPE_COUNT>;

@@ -206,6 +224,16 @@ struct VulkanProgram : public HwProgram, VulkanResource {
    // samplers.
    inline BindingList const& getBindings() const { return mInfo->bindings; }

+    // TODO: this is currently not used. This will replace getLayoutDescriptionList below.
+    // inline descset::DescriptorSetLayout const& getLayoutDescription() const {
+    //    return mInfo->layout;
+    // }
+    // In the usual case, we would have just one layout per program. But in the current setup, we
+    // have a set/layout for each descriptor type. This will be changed in the future.
+    using LayoutDescriptionList = std::array<descset::DescriptorSetLayout,
+            VulkanDescriptorSetLayout::UNIQUE_DESCRIPTOR_SET_COUNT>;
+    inline LayoutDescriptionList const& getLayoutDescriptionList() const { return mInfo->layouts; }
+
    inline uint32_t getPushConstantRangeCount() const {
        return mInfo->pushConstantDescription.getVkRangeCount();
    }
@@ -245,6 +273,10 @@ private:
        utils::FixedCapacityVector<uint16_t> bindingToSamplerIndex;
        VkShaderModule shaders[MAX_SHADER_MODULES] = { VK_NULL_HANDLE };

+        // TODO: Use this instead of `layouts` after Filament-side Descriptor Set API is in place.
+        // descset::DescriptorSetLayout layout;
+        LayoutDescriptionList layouts;
+
        PushConstantDescription pushConstantDescription;

 #if FVK_ENABLED_DEBUG_SAMPLER_NAME
@@ -270,11 +302,9 @@ struct VulkanRenderTarget : private HwRenderTarget, VulkanResource {
    // Creates an offscreen render target.
    VulkanRenderTarget(VkDevice device, VkPhysicalDevice physicalDevice,
            VulkanContext const& context, VmaAllocator allocator,
-            VulkanCommands* commands,
-            VulkanResourceAllocator* handleAllocator,
-            uint32_t width, uint32_t height,
+            VulkanCommands* commands, uint32_t width, uint32_t height,
            uint8_t samples, VulkanAttachment color[MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT],
-            VulkanAttachment depthStencil[2], VulkanStagePool& stagePool, uint8_t layerCount);
+            VulkanAttachment depthStencil[2], VulkanStagePool& stagePool);

    // Creates a special "default" render target (i.e. associated with the swap chain)
    explicit VulkanRenderTarget();
@@ -289,7 +319,6 @@ struct VulkanRenderTarget : private HwRenderTarget, VulkanResource {
    VulkanAttachment& getMsaaDepth();
    uint8_t getColorTargetCount(const VulkanRenderPass& pass) const;
    uint8_t getSamples() const { return mSamples; }
-    uint8_t getLayerCount() const { return mLayerCount; }
    bool hasDepth() const { return mDepth.texture; }
    bool isSwapChain() const { return !mOffscreen; }
    void bindToSwapChain(VulkanSwapChain& surf);
@@ -301,7 +330,6 @@ private:
    VulkanAttachment mMsaaDepthAttachment = {};
    const bool mOffscreen : 1;
    uint8_t mSamples : 7;
-    uint8_t mLayerCount = 1;
 };

 struct VulkanBufferObject;
@@ -454,7 +482,6 @@ private:
    utils::Mutex mFenceMutex;
 };

-
 inline constexpr VkBufferUsageFlagBits getBufferObjectUsage(
        BufferObjectBinding bindingType) noexcept {
    switch(bindingType) {
--- a/filament/backend/src/vulkan/VulkanImageUtility.cpp
+++ b/filament/backend/src/vulkan/VulkanImageUtility.cpp
@@ -131,18 +131,14 @@ getVkTransition(const VulkanLayoutTransition& transition) {

 }// anonymous namespace

-bool transitionLayout(VkCommandBuffer cmdbuffer,
+void transitionLayout(VkCommandBuffer cmdbuffer,
        VulkanLayoutTransition transition) {
    if (transition.oldLayout == transition.newLayout) {
-        return false;
+        return;
    }
    auto [srcAccessMask, dstAccessMask, srcStage, dstStage, oldLayout, newLayout]
            = getVkTransition(transition);

-    if (oldLayout == newLayout) {
-        return false;
-    }
-
    assert_invariant(transition.image != VK_NULL_HANDLE && "No image for transition");
    VkImageMemoryBarrier barrier = {
            .sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER,
@@ -156,7 +152,6 @@ bool transitionLayout(VkCommandBuffer cmdbuffer,
            .subresourceRange = transition.subresources,
    };
    vkCmdPipelineBarrier(cmdbuffer, srcStage, dstStage, 0, 0, nullptr, 0, nullptr, 1, &barrier);
-    return true;
 }

 }// namespace filament::backend
--- a/filament/backend/src/vulkan/VulkanImageUtility.h
+++ b/filament/backend/src/vulkan/VulkanImageUtility.h
@@ -135,9 +135,7 @@ constexpr inline VkImageLayout getVkLayout(VulkanLayout layout) {
    }
 }

-// Returns true if a transition has been added to the command buffer, false otherwis (where there is
-// no transition necessary).
-bool transitionLayout(VkCommandBuffer cmdbuffer, VulkanLayoutTransition transition);
+void transitionLayout(VkCommandBuffer cmdbuffer, VulkanLayoutTransition transition);

 } // namespace imgutil

--- a/filament/backend/src/vulkan/VulkanPipelineCache.cpp
+++ b/filament/backend/src/vulkan/VulkanPipelineCache.cpp
@@ -98,7 +98,7 @@ VulkanPipelineCache::PipelineCacheEntry* VulkanPipelineCache::createPipeline() n
    VkPipelineColorBlendStateCreateInfo colorBlendState;
    colorBlendState = VkPipelineColorBlendStateCreateInfo{};
    colorBlendState.sType = VK_STRUCTURE_TYPE_PIPELINE_COLOR_BLEND_STATE_CREATE_INFO;
-    colorBlendState.attachmentCount = mPipelineRequirements.rasterState.colorTargetCount;    
+    colorBlendState.attachmentCount = 1;
    colorBlendState.pAttachments = colorBlendAttachments;

    // If we reach this point, we need to create and stash a brand new pipeline object.
@@ -184,7 +184,6 @@ VulkanPipelineCache::PipelineCacheEntry* VulkanPipelineCache::createPipeline() n
    vkRaster.polygonMode = VK_POLYGON_MODE_FILL;
    vkRaster.cullMode = raster.cullMode;
    vkRaster.frontFace = raster.frontFace;
-    vkRaster.depthClampEnable = raster.depthClamp;
    vkRaster.depthBiasEnable = raster.depthBiasEnable;
    vkRaster.depthBiasConstantFactor = raster.depthBiasConstantFactor;
    vkRaster.depthBiasClamp = 0.0f;
@@ -210,8 +209,8 @@ VulkanPipelineCache::PipelineCacheEntry* VulkanPipelineCache::createPipeline() n
    pipelineCreateInfo.pDynamicState = &dynamicState;

    // Filament assumes consistent blend state across all color attachments.
-    for (uint8_t i = 0; i < colorBlendState.attachmentCount; ++i) {
-        auto& target = colorBlendAttachments[i];
+    colorBlendState.attachmentCount = mPipelineRequirements.rasterState.colorTargetCount;
+    for (auto& target : colorBlendAttachments) {
        target.blendEnable = mPipelineRequirements.rasterState.blendEnable;
        target.srcColorBlendFactor = mPipelineRequirements.rasterState.srcColorBlendFactor;
        target.dstColorBlendFactor = mPipelineRequirements.rasterState.dstColorBlendFactor;
--- a/filament/backend/src/vulkan/VulkanPipelineCache.h
+++ b/filament/backend/src/vulkan/VulkanPipelineCache.h
@@ -90,8 +90,7 @@ public:
        VkBlendFactor         srcAlphaBlendFactor : 5;
        VkBlendFactor         dstAlphaBlendFactor : 5;
        VkColorComponentFlags colorWriteMask : 4;
-        uint8_t               rasterizationSamples : 4;// offset = 4 bytes
-        uint8_t               depthClamp : 4;
+        uint8_t               rasterizationSamples;    // offset = 4 bytes
        uint8_t               colorTargetCount;        // offset = 5 bytes
        BlendEquation         colorBlendOp : 4;        // offset = 6 bytes
        BlendEquation         alphaBlendOp : 4;
--- a/filament/backend/src/vulkan/VulkanReadPixels.cpp
+++ b/filament/backend/src/vulkan/VulkanReadPixels.cpp
@@ -232,7 +232,7 @@ void VulkanReadPixels::run(VulkanRenderTarget* srcTarget, uint32_t const x, uint

    VulkanAttachment const srcAttachment = srcTarget->getColor(0);
    VkImageSubresourceRange const srcRange = srcAttachment.getSubresourceRange();
-    srcTexture->transitionLayout(cmdbuffer, {}, srcRange, VulkanLayout::TRANSFER_SRC);
+    srcTexture->transitionLayout(cmdbuffer, srcRange, VulkanLayout::TRANSFER_SRC);

    VkImageCopy const imageCopyRegion = {
        .srcSubresource = {
@@ -268,7 +268,7 @@ void VulkanReadPixels::run(VulkanRenderTarget* srcTarget, uint32_t const x, uint
            imgutil::getVkLayout(VulkanLayout::TRANSFER_DST), 1, &imageCopyRegion);

    // Restore the source image layout.
-    srcTexture->transitionLayout(cmdbuffer, {}, srcRange, VulkanLayout::COLOR_ATTACHMENT);
+    srcTexture->transitionLayout(cmdbuffer, srcRange, VulkanLayout::COLOR_ATTACHMENT);

    vkEndCommandBuffer(cmdbuffer);

--- a/filament/backend/src/vulkan/VulkanResourceAllocator.h
+++ b/filament/backend/src/vulkan/VulkanResourceAllocator.h
@@ -105,10 +105,6 @@ public:
        mHandleAllocatorImpl.deallocate(handle, obj);
    }

-    inline void associateHandle(HandleBase::HandleId id, utils::CString&& tag) noexcept {
-        mHandleAllocatorImpl.associateTagToHandle(id, std::move(tag));
-    }
-
 private:
    AllocatorImpl mHandleAllocatorImpl;

--- a/filament/backend/src/vulkan/VulkanSwapChain.cpp
+++ b/filament/backend/src/vulkan/VulkanSwapChain.cpp
@@ -26,14 +26,12 @@ using namespace utils;
 namespace filament::backend {

 VulkanSwapChain::VulkanSwapChain(VulkanPlatform* platform, VulkanContext const& context,
-        VmaAllocator allocator, VulkanCommands* commands, VulkanResourceAllocator* handleAllocator,
-        VulkanStagePool& stagePool,
+        VmaAllocator allocator, VulkanCommands* commands, VulkanStagePool& stagePool,
        void* nativeWindow, uint64_t flags, VkExtent2D extent)
    : VulkanResource(VulkanResourceType::SWAP_CHAIN),
      mPlatform(platform),
      mCommands(commands),
      mAllocator(allocator),
-      mHandleAllocator(handleAllocator),
      mStagePool(stagePool),
      mHeadless(extent.width != 0 && extent.height != 0 && !nativeWindow),
      mFlushAndWaitOnResize(platform->getCustomization().flushAndWaitOnWindowResize),
@@ -64,12 +62,12 @@ void VulkanSwapChain::update() {
    VkDevice const device = mPlatform->getDevice();

    for (auto const color: bundle.colors) {
-        mColors.push_back(std::make_unique<VulkanTexture>(device, mAllocator, mCommands, mHandleAllocator,
-                color, bundle.colorFormat, 1, bundle.extent.width, bundle.extent.height,
+        mColors.push_back(std::make_unique<VulkanTexture>(device, mAllocator, mCommands, color,
+                bundle.colorFormat, 1, bundle.extent.width, bundle.extent.height,
                TextureUsage::COLOR_ATTACHMENT, mStagePool, true /* heap allocated */));
    }
-    mDepth = std::make_unique<VulkanTexture>(device, mAllocator, mCommands, mHandleAllocator,
-            bundle.depth, bundle.depthFormat, 1, bundle.extent.width, bundle.extent.height,
+    mDepth = std::make_unique<VulkanTexture>(device, mAllocator, mCommands, bundle.depth,
+            bundle.depthFormat, 1, bundle.extent.width, bundle.extent.height,
            TextureUsage::DEPTH_ATTACHMENT, mStagePool, true /* heap allocated */);

    mExtent = bundle.extent;
@@ -77,7 +75,7 @@ void VulkanSwapChain::update() {

 void VulkanSwapChain::present() {
    if (!mHeadless && mTransitionSwapChainImageLayoutForPresent) {
-        VulkanCommandBuffer& commands = mCommands->get();
+        VkCommandBuffer const cmdbuf = mCommands->get().buffer();
        VkImageSubresourceRange const subresources{
                .aspectMask = VK_IMAGE_ASPECT_COLOR_BIT,
                .baseMipLevel = 0,
@@ -85,7 +83,7 @@ void VulkanSwapChain::present() {
                .baseArrayLayer = 0,
                .layerCount = 1,
        };
-        mColors[mCurrentSwapIndex]->transitionLayout(&commands, subresources, VulkanLayout::PRESENT);
+        mColors[mCurrentSwapIndex]->transitionLayout(cmdbuf, subresources, VulkanLayout::PRESENT);
    }

    mCommands->flush();
--- a/filament/backend/src/vulkan/VulkanSwapChain.h
+++ b/filament/backend/src/vulkan/VulkanSwapChain.h
@@ -36,13 +36,11 @@ namespace filament::backend {

 struct VulkanHeadlessSwapChain;
 struct VulkanSurfaceSwapChain;
-class VulkanResourceAllocator;

 // A wrapper around the platform implementation of swapchain.
 struct VulkanSwapChain : public HwSwapChain, VulkanResource {
    VulkanSwapChain(VulkanPlatform* platform, VulkanContext const& context, VmaAllocator allocator,
-            VulkanCommands* commands, VulkanResourceAllocator* handleAllocator,
-            VulkanStagePool& stagePool,
+            VulkanCommands* commands, VulkanStagePool& stagePool,
            void* nativeWindow, uint64_t flags, VkExtent2D extent = {0, 0});

    ~VulkanSwapChain();
@@ -82,7 +80,6 @@ private:
    VulkanPlatform* mPlatform;
    VulkanCommands* mCommands;
    VmaAllocator mAllocator;
-    VulkanResourceAllocator* const mHandleAllocator;
    VulkanStagePool& mStagePool;
    bool const mHeadless;
    bool const mFlushAndWaitOnResize;
--- a/filament/backend/src/vulkan/VulkanTexture.cpp
+++ b/filament/backend/src/vulkan/VulkanTexture.cpp
@@ -15,7 +15,6 @@
 */

 #include "VulkanMemory.h"
-#include "VulkanResourceAllocator.h"
 #include "VulkanTexture.h"
 #include "VulkanUtility.h"

@@ -29,138 +28,50 @@ using namespace bluevk;

 namespace filament::backend {

-namespace {
-
-inline uint8_t getLayerCount(SamplerType const target, uint32_t const depth) {
-    switch (target) {
-        case SamplerType::SAMPLER_2D:
-        case SamplerType::SAMPLER_3D:
-        case SamplerType::SAMPLER_EXTERNAL:
-            return 1;
-        case SamplerType::SAMPLER_CUBEMAP:
-            return 6;
-        case SamplerType::SAMPLER_CUBEMAP_ARRAY:
-            return depth * 6;
-        case SamplerType::SAMPLER_2D_ARRAY:
-            return depth;
-    }
-}
-
-VkComponentMapping composeSwizzle(VkComponentMapping const& prev, VkComponentMapping const& next) {
-    static constexpr VkComponentSwizzle IDENTITY[] = {
-        VK_COMPONENT_SWIZZLE_R,
-        VK_COMPONENT_SWIZZLE_G,
-        VK_COMPONENT_SWIZZLE_B,
-        VK_COMPONENT_SWIZZLE_A,
-    };
-
-    auto const compose = [](VkComponentSwizzle out, VkComponentMapping const& prev,
-                                 uint8_t channelIndex) {
-        // We need to first change all identities to its equivalent channel.
-        if (out == VK_COMPONENT_SWIZZLE_IDENTITY) {
-            out = IDENTITY[channelIndex];
-        }
-        switch (out) {
-            case VK_COMPONENT_SWIZZLE_R:
-                out = prev.r;
-                break;
-            case VK_COMPONENT_SWIZZLE_G:
-                out = prev.g;
-                break;
-            case VK_COMPONENT_SWIZZLE_B:
-                out = prev.b;
-                break;
-            case VK_COMPONENT_SWIZZLE_A:
-                out = prev.a;
-                break;
-            case VK_COMPONENT_SWIZZLE_IDENTITY:
-            case VK_COMPONENT_SWIZZLE_ZERO:
-            case VK_COMPONENT_SWIZZLE_ONE:
-                return out;
-            // Below is not exposed in Vulkan's API, but needs to be there for compilation.
-            case VK_COMPONENT_SWIZZLE_MAX_ENUM:
-                break;
-        }
-        // If the result correctly corresponds to the identity, just return identity.
-        if (IDENTITY[channelIndex] == out) {
-            return VK_COMPONENT_SWIZZLE_IDENTITY;
-        }
-        return out;
-    };
-
-    // Note that the channel index corresponds to the VkComponentMapping struct layout.
-    return {
-        compose(next.r, prev, 0),
-        compose(next.g, prev, 1),
-        compose(next.b, prev, 2),
-        compose(next.a, prev, 3),
-    };
-}
-
-} // anonymous namespace
-
-VulkanTextureState::VulkanTextureState(
-        VkDevice device, VmaAllocator allocator, VulkanCommands* commands,
-        VulkanStagePool& stagePool,
-        VkFormat format, VkImageViewType viewType, uint8_t levels, uint8_t layerCount)
-        : VulkanResource(VulkanResourceType::HEAP_ALLOCATED),
-          mVkFormat(format),
-          mViewType(viewType),
-          mFullViewRange {
-                  filament::backend::getImageAspect(format), 0, levels, 0, layerCount
-          },
-          mStagePool(stagePool),
-          mDevice(device),
-          mAllocator(allocator),
-          mCommands(commands) {
-}
-
-VulkanTextureState* VulkanTexture::getSharedState() {
-    VulkanTextureState* state = mAllocator->handle_cast<VulkanTextureState*>(mState);
-    return state;
-}
-
-VulkanTextureState const* VulkanTexture::getSharedState() const {
-    VulkanTextureState const* state = mAllocator->handle_cast<VulkanTextureState const*>(mState);
-    return state;
-}
-
-VulkanTexture::VulkanTexture(
-        VkDevice device, VmaAllocator allocator, VulkanCommands* commands,
-        VulkanResourceAllocator* handleAllocator,
+VulkanTexture::VulkanTexture(VkDevice device, VmaAllocator allocator, VulkanCommands* commands,
        VkImage image, VkFormat format, uint8_t samples, uint32_t width, uint32_t height,
        TextureUsage tusage, VulkanStagePool& stagePool, bool heapAllocated)
-        : HwTexture(SamplerType::SAMPLER_2D, 1, samples, width, height, 1, TextureFormat::UNUSED,
-                tusage),
-          VulkanResource(
-                  heapAllocated ? VulkanResourceType::HEAP_ALLOCATED : VulkanResourceType::TEXTURE),
-          mAllocator(handleAllocator),
-          mState(handleAllocator->initHandle<VulkanTextureState>(
-                  device, allocator, commands, stagePool,
-                  format, imgutil::getViewType(SamplerType::SAMPLER_2D), 1, 1)) {
-    auto* const state = getSharedState();
-    state->mTextureImage = image;
-    mPrimaryViewRange = state->mFullViewRange;
-}
+    : HwTexture(SamplerType::SAMPLER_2D, 1, samples, width, height, 1, TextureFormat::UNUSED,
+            tusage),
+      VulkanResource(
+              heapAllocated ? VulkanResourceType::HEAP_ALLOCATED : VulkanResourceType::TEXTURE),
+      mVkFormat(format),
+      mViewType(imgutil::getViewType(target)),
+      mSwizzle({}),
+      mTextureImage(image),
+      mFullViewRange{
+              .aspectMask = getImageAspect(),
+              .baseMipLevel = 0,
+              .levelCount = 1,
+              .baseArrayLayer = 0,
+              .layerCount = 1,
+      },
+      mPrimaryViewRange(mFullViewRange),
+      mStagePool(stagePool),
+      mDevice(device),
+      mAllocator(allocator),
+      mCommands(commands) {}

 VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
        VulkanContext const& context, VmaAllocator allocator, VulkanCommands* commands,
-        VulkanResourceAllocator* handleAllocator, SamplerType target, uint8_t levels,
-        TextureFormat tformat, uint8_t samples, uint32_t w, uint32_t h, uint32_t depth,
-        TextureUsage tusage, VulkanStagePool& stagePool, bool heapAllocated)
+        SamplerType target, uint8_t levels, TextureFormat tformat, uint8_t samples, uint32_t w,
+        uint32_t h, uint32_t depth, TextureUsage tusage, VulkanStagePool& stagePool,
+        bool heapAllocated, VkComponentMapping swizzle)
    : HwTexture(target, levels, samples, w, h, depth, tformat, tusage),
      VulkanResource(
              heapAllocated ? VulkanResourceType::HEAP_ALLOCATED : VulkanResourceType::TEXTURE),
-      mAllocator(handleAllocator),
-      mState(handleAllocator->initHandle<VulkanTextureState>(device, allocator, commands, stagePool,
-              backend::getVkFormat(tformat), imgutil::getViewType(target), levels,
-              getLayerCount(target, depth))) {
-    auto* const state = getSharedState();
+      mVkFormat(backend::getVkFormat(tformat)),
+      mViewType(imgutil::getViewType(target)),
+      mSwizzle(swizzle),
+      mStagePool(stagePool),
+      mDevice(device),
+      mAllocator(allocator),
+      mCommands(commands) {

    // Create an appropriately-sized device-only VkImage, but do not fill it yet.
    VkImageCreateInfo imageInfo{.sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,
            .imageType = target == SamplerType::SAMPLER_3D ? VK_IMAGE_TYPE_3D : VK_IMAGE_TYPE_2D,
-            .format = state->mVkFormat,
+            .format = mVkFormat,
            .extent = {w, h, depth},
            .mipLevels = levels,
            .arrayLayers = 1,
@@ -186,11 +97,13 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
        imageInfo.extent.depth = 1;
    }

-    if (any(usage & TextureUsage::BLIT_SRC)) {
-        imageInfo.usage |= VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
-    }
-    if (any(usage & TextureUsage::BLIT_DST)) {
-        imageInfo.usage |= VK_IMAGE_USAGE_TRANSFER_DST_BIT;
+    // Filament expects blit() to work with any texture, so we almost always set these usage flags.
+    // TODO: investigate performance implications of setting these flags.
+    constexpr VkImageUsageFlags blittable = VK_IMAGE_USAGE_TRANSFER_DST_BIT |
+            VK_IMAGE_USAGE_TRANSFER_SRC_BIT;
+
+    if (any(usage & (TextureUsage::BLIT_DST | TextureUsage::BLIT_SRC))) {
+        imageInfo.usage |= blittable;
    }

    if (any(usage & TextureUsage::SAMPLEABLE)) {
@@ -198,9 +111,9 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
 #if FVK_ENABLED(FVK_DEBUG_TEXTURE)
        // Validate that the format is actually sampleable.
        VkFormatProperties props;
-        vkGetPhysicalDeviceFormatProperties(physicalDevice, state->mVkFormat, &props);
+        vkGetPhysicalDeviceFormatProperties(physicalDevice, mVkFormat, &props);
        if (!(props.optimalTilingFeatures & VK_FORMAT_FEATURE_SAMPLED_IMAGE_BIT)) {
-            FVK_LOGW << "Texture usage is SAMPLEABLE but format " << state->mVkFormat << " is not "
+            FVK_LOGW << "Texture usage is SAMPLEABLE but format " << mVkFormat << " is not "
                    "sampleable with optimal tiling." << utils::io::endl;
        }
 #endif
@@ -208,7 +121,7 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
        imageInfo.usage |= VK_IMAGE_USAGE_SAMPLED_BIT;
    }
    if (any(usage & TextureUsage::COLOR_ATTACHMENT)) {
-        imageInfo.usage |= VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT;
+        imageInfo.usage |= VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | blittable;
        if (any(usage & TextureUsage::SUBPASS_INPUT)) {
            imageInfo.usage |= VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT;
        }
@@ -217,9 +130,10 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
        imageInfo.usage |= VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
    }
    if (any(usage & TextureUsage::UPLOADABLE)) {
-        imageInfo.usage |= VK_IMAGE_USAGE_TRANSFER_DST_BIT;
+        imageInfo.usage |= blittable;
    }
    if (any(usage & TextureUsage::DEPTH_ATTACHMENT)) {
+        imageInfo.usage |= blittable;
        imageInfo.usage |= VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;

        // Depth resolves uses a custom shader and therefore needs to be sampleable.
@@ -233,7 +147,7 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
    // any kind of attachment (color or depth).
    const auto& limits = context.getPhysicalDeviceLimits();
    if (imageInfo.usage & VK_IMAGE_USAGE_SAMPLED_BIT) {
-        samples = reduceSampleCount(samples, isVkDepthFormat(state->mVkFormat)
+        samples = reduceSampleCount(samples, isVkDepthFormat(mVkFormat)
                                                     ? limits.sampledImageDepthSampleCounts
                                                     : limits.sampledImageColorSampleCounts);
    }
@@ -247,12 +161,12 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
    this->samples = samples;
    imageInfo.samples = (VkSampleCountFlagBits) samples;

-    VkResult error = vkCreateImage(state->mDevice, &imageInfo, VKALLOC, &state->mTextureImage);
+    VkResult error = vkCreateImage(mDevice, &imageInfo, VKALLOC, &mTextureImage);
    if (error || FVK_ENABLED(FVK_DEBUG_TEXTURE)) {
        FVK_LOGD << "vkCreateImage: "
-            << "image = " << state->mTextureImage << ", "
+            << "image = " << mTextureImage << ", "
            << "result = " << error << ", "
-            << "handle = " << utils::io::hex << state->mTextureImage << utils::io::dec << ", "
+            << "handle = " << utils::io::hex << mTextureImage << utils::io::dec << ", "
            << "extent = " << w << "x" << h << "x"<< depth << ", "
            << "mipLevels = " << int(levels) << ", "
            << "TextureUsage = " << static_cast<int>(usage) << ", "
@@ -261,13 +175,13 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
            << "type = " << imageInfo.imageType << ", "
            << "flags = " << imageInfo.flags << ", "
            << "target = " << static_cast<int>(target) <<", "
-            << "format = " << state->mVkFormat << utils::io::endl;
+            << "format = " << mVkFormat << utils::io::endl;
    }
    FILAMENT_CHECK_POSTCONDITION(!error) << "Unable to create image.";

    // Allocate memory for the VkImage and bind it.
    VkMemoryRequirements memReqs = {};
-    vkGetImageMemoryRequirements(state->mDevice, state->mTextureImage, &memReqs);
+    vkGetImageMemoryRequirements(mDevice, mTextureImage, &memReqs);

    uint32_t memoryTypeIndex
            = context.selectMemoryType(memReqs.memoryTypeBits, VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT);
@@ -280,67 +194,58 @@ VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
        .allocationSize = memReqs.size,
        .memoryTypeIndex = memoryTypeIndex,
    };
-    error = vkAllocateMemory(state->mDevice, &allocInfo, nullptr, &state->mTextureImageMemory);
+    error = vkAllocateMemory(mDevice, &allocInfo, nullptr, &mTextureImageMemory);
    FILAMENT_CHECK_POSTCONDITION(!error) << "Unable to allocate image memory.";
-    error = vkBindImageMemory(state->mDevice, state->mTextureImage, state->mTextureImageMemory, 0);
+    error = vkBindImageMemory(mDevice, mTextureImage, mTextureImageMemory, 0);
    FILAMENT_CHECK_POSTCONDITION(!error) << "Unable to bind image.";

+    uint32_t layerCount = 0;
+    if (target == SamplerType::SAMPLER_CUBEMAP) {
+        layerCount = 6;
+    } else if (target == SamplerType::SAMPLER_CUBEMAP_ARRAY) {
+        layerCount = depth * 6;
+    } else if (target == SamplerType::SAMPLER_2D_ARRAY) {
+        layerCount = depth;
+    } else if (target == SamplerType::SAMPLER_3D) {
+        layerCount = 1;
+    } else {
+        layerCount = 1;
+    }
+
+    mFullViewRange = {
+        .aspectMask = getImageAspect(),
+        .baseMipLevel = 0,
+        .levelCount = levels,
+        .baseArrayLayer = 0,
+        .layerCount = layerCount,
+    };
+
    // Spec out the "primary" VkImageView that shaders use to sample from the image.
-    mPrimaryViewRange = state->mFullViewRange;
+    mPrimaryViewRange = mFullViewRange;

    // Go ahead and create the primary image view.
-    getImageView(mPrimaryViewRange, state->mViewType, mSwizzle);
+    getImageView(mPrimaryViewRange, mViewType, mSwizzle);

-    VulkanCommandBuffer& commandsBuf = state->mCommands->get();
-    commandsBuf.acquire(this);
-    transitionLayout(&commandsBuf, mPrimaryViewRange, imgutil::getDefaultLayout(imageInfo.usage));
-}
-
-VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
-        VulkanContext const& context, VmaAllocator allocator, VulkanCommands* commands,
-        VulkanResourceAllocator* handleAllocator,
-        VulkanTexture const* src, uint8_t baseLevel, uint8_t levelCount)
-        : HwTexture(src->target, src->levels, src->samples, src->width, src->height, src->depth,
-                src->format, src->usage),
-          VulkanResource(VulkanResourceType::TEXTURE),
-          mAllocator(handleAllocator)
-{
-    mState = src->mState;
-    auto* state = getSharedState();
-
-    state->refs++;
-    mPrimaryViewRange = src->mPrimaryViewRange;
-    mPrimaryViewRange.baseMipLevel = src->mPrimaryViewRange.baseMipLevel + baseLevel;
-    mPrimaryViewRange.levelCount = levelCount;
-}
-
-VulkanTexture::VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice,
-        VulkanContext const& context, VmaAllocator allocator, VulkanCommands* commands,
-        VulkanResourceAllocator* handleAllocator,
-        VulkanTexture const* src, VkComponentMapping swizzle)
-        : HwTexture(src->target, src->levels, src->samples, src->width, src->height, src->depth,
-                src->format, src->usage),
-          VulkanResource(VulkanResourceType::TEXTURE),
-          mAllocator(handleAllocator) {
-    mState = src->mState;
-    auto* state = getSharedState();
-    state->refs++;
-    mPrimaryViewRange = src->mPrimaryViewRange;
-    mSwizzle = composeSwizzle(src->mSwizzle, swizzle);
+    // Transition the layout of each image slice that might be used as a render target.
+    // We do not transition images that are merely SAMPLEABLE, this is deferred until upload time
+    // because we do not know how many layers and levels will actually be used.
+    if (imageInfo.usage
+        & (VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT
+           | VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT)) {
+        VulkanCommandBuffer& commands = mCommands->get();
+        VkCommandBuffer const cmdbuf = commands.buffer();
+        commands.acquire(this);
+        transitionLayout(cmdbuf, mFullViewRange, imgutil::getDefaultLayout(imageInfo.usage));
+    }
 }

 VulkanTexture::~VulkanTexture() {
-    auto* const state = getSharedState();
-    state->refs--;
-    if (state->refs == 0) {
-        if (state->mTextureImageMemory != VK_NULL_HANDLE) {
-            vkDestroyImage(state->mDevice, state->mTextureImage, VKALLOC);
-            vkFreeMemory(state->mDevice, state->mTextureImageMemory, VKALLOC);
-        }
-        for (auto entry: state->mCachedImageViews) {
-            vkDestroyImageView(state->mDevice, entry.second, VKALLOC);
-        }
-        mAllocator->destruct<VulkanTextureState>(mState);
+    if (mTextureImageMemory != VK_NULL_HANDLE) {
+        vkDestroyImage(mDevice, mTextureImage, VKALLOC);
+        vkFreeMemory(mDevice, mTextureImageMemory, VKALLOC);
+    }
+    for (auto entry : mCachedImageViews) {
+        vkDestroyImageView(mDevice, entry.second, VKALLOC);
    }
 }

@@ -349,7 +254,7 @@ void VulkanTexture::updateImage(const PixelBufferDescriptor& data, uint32_t widt
    assert_invariant(width <= this->width && height <= this->height);
    assert_invariant(depth <= this->depth * ((target == SamplerType::SAMPLER_CUBEMAP ||
                        target == SamplerType::SAMPLER_CUBEMAP_ARRAY) ? 6 : 1));
-    auto* const state = getSharedState();
+
    const PixelBufferDescriptor* hostData = &data;
    PixelBufferDescriptor reshapedData;

@@ -362,7 +267,7 @@ void VulkanTexture::updateImage(const PixelBufferDescriptor& data, uint32_t widt

    // If format conversion is both required and supported, use vkCmdBlitImage.
    const VkFormat hostFormat = backend::getVkFormat(hostData->format, hostData->type);
-    const VkFormat deviceFormat = getVkFormatLinear(state->mVkFormat);
+    const VkFormat deviceFormat = getVkFormatLinear(mVkFormat);
    if (hostFormat != deviceFormat && hostFormat != VK_FORMAT_UNDEFINED) {
        assert_invariant(xoffset == 0 && yoffset == 0 && zoffset == 0 &&
                "Offsets not yet supported when format conversion is required.");
@@ -374,14 +279,14 @@ void VulkanTexture::updateImage(const PixelBufferDescriptor& data, uint32_t widt

    // Otherwise, use vkCmdCopyBufferToImage.
    void* mapped = nullptr;
-    VulkanStage const* stage = state->mStagePool.acquireStage(hostData->size);
+    VulkanStage const* stage = mStagePool.acquireStage(hostData->size);
    assert_invariant(stage->memory);
-    vmaMapMemory(state->mAllocator, stage->memory, &mapped);
+    vmaMapMemory(mAllocator, stage->memory, &mapped);
    memcpy(mapped, hostData->buffer, hostData->size);
-    vmaUnmapMemory(state->mAllocator, stage->memory);
-    vmaFlushAllocation(state->mAllocator, stage->memory, 0, hostData->size);
+    vmaUnmapMemory(mAllocator, stage->memory);
+    vmaFlushAllocation(mAllocator, stage->memory, 0, hostData->size);

-    VulkanCommandBuffer& commands = state->mCommands->get();
+    VulkanCommandBuffer& commands = mCommands->get();
    VkCommandBuffer const cmdbuf = commands.buffer();
    commands.acquire(this);

@@ -427,25 +332,24 @@ void VulkanTexture::updateImage(const PixelBufferDescriptor& data, uint32_t widt
        nextLayout = imgutil::getDefaultLayout(this->usage);
    }

-    transitionLayout(&commands, transitionRange, newLayout);
+    transitionLayout(cmdbuf, transitionRange, newLayout);

-    vkCmdCopyBufferToImage(cmdbuf, stage->buffer, state->mTextureImage, newVkLayout, 1, &copyRegion);
+    vkCmdCopyBufferToImage(cmdbuf, stage->buffer, mTextureImage, newVkLayout, 1, &copyRegion);

-    transitionLayout(&commands, transitionRange, nextLayout);
+    transitionLayout(cmdbuf, transitionRange, nextLayout);
 }

 void VulkanTexture::updateImageWithBlit(const PixelBufferDescriptor& hostData, uint32_t width,
        uint32_t height, uint32_t depth, uint32_t miplevel) {
-    auto* const state = getSharedState();
    void* mapped = nullptr;
    VulkanStageImage const* stage
-            = state->mStagePool.acquireImage(hostData.format, hostData.type, width, height);
-    vmaMapMemory(state->mAllocator, stage->memory, &mapped);
+            = mStagePool.acquireImage(hostData.format, hostData.type, width, height);
+    vmaMapMemory(mAllocator, stage->memory, &mapped);
    memcpy(mapped, hostData.buffer, hostData.size);
-    vmaUnmapMemory(state->mAllocator, stage->memory);
-    vmaFlushAllocation(state->mAllocator, stage->memory, 0, hostData.size);
+    vmaUnmapMemory(mAllocator, stage->memory);
+    vmaFlushAllocation(mAllocator, stage->memory, 0, hostData.size);

-    VulkanCommandBuffer& commands = state->mCommands->get();
+    VulkanCommandBuffer& commands = mCommands->get();
    VkCommandBuffer const cmdbuf = commands.buffer();
    commands.acquire(this);

@@ -467,68 +371,63 @@ void VulkanTexture::updateImageWithBlit(const PixelBufferDescriptor& hostData, u

    VulkanLayout const newLayout = VulkanLayout::TRANSFER_DST;
    VulkanLayout const oldLayout = getLayout(layer, miplevel);
-    transitionLayout(&commands, range, newLayout);
+    transitionLayout(cmdbuf, range, newLayout);

    vkCmdBlitImage(cmdbuf, stage->image, imgutil::getVkLayout(VulkanLayout::TRANSFER_SRC),
-            state->mTextureImage, imgutil::getVkLayout(newLayout), 1, blitRegions, VK_FILTER_NEAREST);
+            mTextureImage, imgutil::getVkLayout(newLayout), 1, blitRegions, VK_FILTER_NEAREST);

-    transitionLayout(&commands, range, oldLayout);
+    transitionLayout(cmdbuf, range, oldLayout);
+}
+
+void VulkanTexture::setPrimaryRange(uint32_t minMiplevel, uint32_t maxMiplevel) {
+    maxMiplevel = filament::math::min(int(maxMiplevel), int(this->levels - 1));
+    mPrimaryViewRange.baseMipLevel = minMiplevel;
+    mPrimaryViewRange.levelCount = maxMiplevel - minMiplevel + 1;
+    getImageView(mPrimaryViewRange, mViewType, mSwizzle);
 }

 VkImageView VulkanTexture::getAttachmentView(VkImageSubresourceRange range) {
+    // Attachments should only have one mipmap level and one layer.
    range.levelCount = 1;
    range.layerCount = 1;
    return getImageView(range, VK_IMAGE_VIEW_TYPE_2D, {});
 }

-VkImageView VulkanTexture::getMultiviewAttachmentView(VkImageSubresourceRange range) {
-    return getImageView(range, VK_IMAGE_VIEW_TYPE_2D_ARRAY, {});
-}
-
 VkImageView VulkanTexture::getViewForType(VkImageSubresourceRange const& range, VkImageViewType type) {
    return getImageView(range, type, mSwizzle);
 }

 VkImageView VulkanTexture::getImageView(VkImageSubresourceRange range, VkImageViewType viewType,
        VkComponentMapping swizzle) {
-    auto* const state = getSharedState();
-    VulkanTextureState::ImageViewKey const key{ range, viewType, swizzle };
-    auto iter = state->mCachedImageViews.find(key);
-    if (iter != state->mCachedImageViews.end()) {
+    ImageViewKey const key {range, viewType, swizzle};
+    auto iter = mCachedImageViews.find(key);
+    if (iter != mCachedImageViews.end()) {
        return iter->second;
    }
    VkImageViewCreateInfo viewInfo = {
        .sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO,
        .pNext = nullptr,
        .flags = 0,
-        .image = state->mTextureImage,
+        .image = mTextureImage,
        .viewType = viewType,
-        .format = state->mVkFormat,
+        .format = mVkFormat,
        .components = swizzle,
        .subresourceRange = range,
    };
    VkImageView imageView;
-    vkCreateImageView(state->mDevice, &viewInfo, VKALLOC, &imageView);
-    state->mCachedImageViews.emplace(key, imageView);
+    vkCreateImageView(mDevice, &viewInfo, VKALLOC, &imageView);
+    mCachedImageViews.emplace(key, imageView);
    return imageView;
 }

 VkImageAspectFlags VulkanTexture::getImageAspect() const {
    // Helper function in VulkanUtility
-    auto* const state = getSharedState();
-    return filament::backend::getImageAspect(state->mVkFormat);
+    return filament::backend::getImageAspect(mVkFormat);
 }

-bool VulkanTexture::transitionLayout(VulkanCommandBuffer* commands,
-        const VkImageSubresourceRange& range, VulkanLayout newLayout) {
-    return transitionLayout(commands->buffer(), commands->fence, range, newLayout);
-}
-
-bool VulkanTexture::transitionLayout(
-        VkCommandBuffer cmdbuf, std::shared_ptr<VulkanCmdFence> fence,
-        const VkImageSubresourceRange& range,
+void VulkanTexture::transitionLayout(VkCommandBuffer cmdbuf, const VkImageSubresourceRange& range,
        VulkanLayout newLayout) {
-    auto* const state = getSharedState();
+
    VulkanLayout const oldLayout = getLayout(range.baseArrayLayer, range.baseMipLevel);

    uint32_t const firstLayer = range.baseArrayLayer;
@@ -539,7 +438,7 @@ bool VulkanTexture::transitionLayout(
    // If we are transitioning more than one layer/level (slice), we need to know whether they are
    // all of the same layer.  If not, we need to transition slice-by-slice. Otherwise it would
    // trigger the validation layer saying that the `oldLayout` provided is incorrect.
-    // TODO: transition by multiple slices with more sophisticated range finding.
+    // TODO: transition by multiple slices with more sophiscated range finding.
    bool transitionSliceBySlice = false;
    for (uint32_t i = firstLayer; i < lastLayer; ++i) {
        for (uint32_t j = firstLevel; j < lastLevel; ++j) {
@@ -550,82 +449,50 @@ bool VulkanTexture::transitionLayout(
        }
    }

-    bool hasTransitions = false;
+#if FVK_ENABLED(FVK_DEBUG_LAYOUT_TRANSITION)
+    FVK_LOGD << "transition texture=" << mTextureImage
+                  << " (" << range.baseArrayLayer
+                  << "," << range.baseMipLevel << ")"
+                  << " count=(" << range.layerCount
+                  << "," << range.levelCount << ")"
+                  << " from=" << oldLayout << " to=" << newLayout
+                  << " format=" << mVkFormat
+                  << " depth=" << isVkDepthFormat(mVkFormat)
+                  << " slice-by-slice=" << transitionSliceBySlice
+                  << utils::io::endl;
+#endif
+
    if (transitionSliceBySlice) {
        for (uint32_t i = firstLayer; i < lastLayer; ++i) {
            for (uint32_t j = firstLevel; j < lastLevel; ++j) {
                VulkanLayout const layout = getLayout(i, j);
-                if (layout == newLayout) {
-                    continue;
-                }
-                hasTransitions = hasTransitions || imgutil::transitionLayout(cmdbuf, {
-                    .image = state->mTextureImage,
-                    .oldLayout = layout,
-                    .newLayout = newLayout,
-                    .subresources = {
-                        .aspectMask = range.aspectMask,
-                        .baseMipLevel = j,
-                        .levelCount = 1,
-                        .baseArrayLayer = i,
-                        .layerCount = 1,
-                    },
-                });
+                imgutil::transitionLayout(cmdbuf, {
+                        .image = mTextureImage,
+                        .oldLayout = layout,
+                        .newLayout = newLayout,
+                        .subresources = {
+                            .aspectMask = range.aspectMask,
+                            .baseMipLevel = j,
+                            .levelCount = 1,
+                            .baseArrayLayer = i,
+                            .layerCount = 1,
+                        },
+                    });
            }
        }
-    } else if (newLayout != oldLayout) {
-        hasTransitions = imgutil::transitionLayout(cmdbuf, {
-            .image = state->mTextureImage,
+    } else {
+        imgutil::transitionLayout(cmdbuf, {
+            .image = mTextureImage,
            .oldLayout = oldLayout,
            .newLayout = newLayout,
            .subresources = range,
        });
    }

-    if (hasTransitions) {
-        state->mTransitionFence = fence;
-        setLayout(range, newLayout);
-
-#if FVK_ENABLED(FVK_DEBUG_LAYOUT_TRANSITION)
-        FVK_LOGD << "transition texture=" << state->mTextureImage << " (" << range.baseArrayLayer
-                 << "," << range.baseMipLevel << ")" << " count=(" << range.layerCount << ","
-                 << range.levelCount << ")" << " from=" << oldLayout << " to=" << newLayout
-                 << " format=" << state->mVkFormat << " depth=" << isVkDepthFormat(state->mVkFormat)
-                 << " slice-by-slice=" << transitionSliceBySlice << utils::io::endl;
-#endif
-    } else {
-#if FVK_ENABLED(FVK_DEBUG_LAYOUT_TRANSITION)
-        FVK_LOGD << "transition texture=" << state->mTextureImage << " (" << range.baseArrayLayer
-                 << "," << range.baseMipLevel << ")" << " count=(" << range.layerCount << ","
-                 << range.levelCount << ")" << " to=" << newLayout
-                 << " is skipped because of no change in layout" << utils::io::endl;
-#endif
-    }
-    return hasTransitions;
+    setLayout(range, newLayout);
 }

-void VulkanTexture::attachmentToSamplerBarrier(VulkanCommandBuffer* commands,
-        VkImageSubresourceRange const& range) {
-    VkCommandBuffer const cmdbuf = commands->buffer();
-    auto* const state = getSharedState();
-    VkImageLayout const layout
-            = imgutil::getVkLayout(getLayout(range.baseArrayLayer, range.baseMipLevel));
-    VkImageMemoryBarrier barrier = {
-            .sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER,
-            .srcAccessMask = VK_ACCESS_COLOR_ATTACHMENT_WRITE_BIT,
-            .dstAccessMask = VK_ACCESS_SHADER_READ_BIT,
-            .oldLayout = layout,
-            .newLayout = layout,
-            .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
-            .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
-            .image = state->mTextureImage,
-            .subresourceRange = range,
-    };
-    vkCmdPipelineBarrier(cmdbuf, VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT,
-            VK_PIPELINE_STAGE_FRAGMENT_SHADER_BIT, 0, 0, nullptr, 0, nullptr, 1, &barrier);
-}
-
-void VulkanTexture::setLayout(VkImageSubresourceRange const& range, VulkanLayout newLayout) {
-    auto* const state = getSharedState();
+void VulkanTexture::setLayout(const VkImageSubresourceRange& range, VulkanLayout newLayout) {
    uint32_t const firstLayer = range.baseArrayLayer;
    uint32_t const lastLayer = firstLayer + range.layerCount;
    uint32_t const firstLevel = range.baseMipLevel;
@@ -638,30 +505,28 @@ void VulkanTexture::setLayout(VkImageSubresourceRange const& range, VulkanLayout
        for (uint32_t layer = firstLayer; layer < lastLayer; ++layer) {
            uint32_t const first = (layer << 16) | firstLevel;
            uint32_t const last = (layer << 16) | lastLevel;
-            state->mSubresourceLayouts.clear(first, last);
+            mSubresourceLayouts.clear(first, last);
        }
    } else {
        for (uint32_t layer = firstLayer; layer < lastLayer; ++layer) {
            uint32_t const first = (layer << 16) | firstLevel;
            uint32_t const last = (layer << 16) | lastLevel;
-            state->mSubresourceLayouts.add(first, last, newLayout);
+            mSubresourceLayouts.add(first, last, newLayout);
        }
    }
 }

 VulkanLayout VulkanTexture::getLayout(uint32_t layer, uint32_t level) const {
    assert_invariant(level <= 0xffff && layer <= 0xffff);
-    auto* const state = getSharedState();
    const uint32_t key = (layer << 16) | level;
-    if (!state->mSubresourceLayouts.has(key)) {
+    if (!mSubresourceLayouts.has(key)) {
        return VulkanLayout::UNDEFINED;
    }
-    return state->mSubresourceLayouts.get(key);
+    return mSubresourceLayouts.get(key);
 }

 #if FVK_ENABLED(FVK_DEBUG_TEXTURE)
 void VulkanTexture::print() const {
-    auto* const state = getSharedState();
    uint32_t const firstLayer = 0;
    uint32_t const lastLayer = firstLayer + mFullViewRange.layerCount;
    uint32_t const firstLevel = 0;
@@ -674,16 +539,16 @@ void VulkanTexture::print() const {
                layer < (mPrimaryViewRange.baseArrayLayer + mPrimaryViewRange.layerCount) &&
                level >= mPrimaryViewRange.baseMipLevel &&
                level < (mPrimaryViewRange.baseMipLevel + mPrimaryViewRange.levelCount);
-            FVK_LOGD << "[" << state->mTextureImage << "]: (" << layer << "," << level
+            FVK_LOGD << "[" << mTextureImage << "]: (" << layer << "," << level
                          << ")=" << getLayout(layer, level)
                          << " primary=" << primary
                          << utils::io::endl;
        }
    }

-    for (auto view: state->mCachedImageViews) {
+    for (auto view: mCachedImageViews) {
        auto& range = view.first.range;
-        FVK_LOGD << "[" << state->mTextureImage << ", imageView=" << view.second << "]=>"
+        FVK_LOGD << "[" << mTextureImage << ", imageView=" << view.second << "]=>"
                      << " (" << range.baseArrayLayer << "," << range.baseMipLevel << ")"
                      << " count=(" << range.layerCount << "," << range.levelCount << ")"
                      << " aspect=" << range.aspectMask << " viewType=" << view.first.type
--- a/filament/backend/src/vulkan/VulkanTexture.h
+++ b/filament/backend/src/vulkan/VulkanTexture.h
@@ -30,12 +30,84 @@

 namespace filament::backend {

-class VulkanResourceAllocator;
+struct VulkanTexture : public HwTexture, VulkanResource {
+    // Standard constructor for user-facing textures.
+    VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice, VulkanContext const& context,
+            VmaAllocator allocator, VulkanCommands* commands, SamplerType target, uint8_t levels,
+            TextureFormat tformat, uint8_t samples, uint32_t w, uint32_t h, uint32_t depth,
+            TextureUsage tusage, VulkanStagePool& stagePool, bool heapAllocated = false,
+            VkComponentMapping swizzle = {});

-struct VulkanTextureState : public VulkanResource {
-    VulkanTextureState(VkDevice device, VmaAllocator allocator, VulkanCommands* commands,
-            VulkanStagePool& stagePool,
-            VkFormat format, VkImageViewType viewType, uint8_t levels, uint8_t layerCount);
+    // Specialized constructor for internally created textures (e.g. from a swap chain)
+    // The texture will never destroy the given VkImage, but it does manages its subresources.
+    VulkanTexture(VkDevice device, VmaAllocator allocator, VulkanCommands* commands, VkImage image,
+            VkFormat format, uint8_t samples, uint32_t width, uint32_t height, TextureUsage tusage,
+            VulkanStagePool& stagePool, bool heapAllocated = false);
+
+    ~VulkanTexture();
+
+    // Uploads data into a subregion of a 2D or 3D texture.
+    void updateImage(const PixelBufferDescriptor& data, uint32_t width, uint32_t height,
+            uint32_t depth, uint32_t xoffset, uint32_t yoffset, uint32_t zoffset, uint32_t miplevel);
+
+    // Returns the primary image view, which is used for shader sampling.
+    VkImageView getPrimaryImageView() {
+        return getImageView(mPrimaryViewRange, mViewType, mSwizzle);
+    }
+
+    VkImageViewType getViewType() const { return mViewType; }
+
+    // Sets the min/max range of miplevels in the primary image view.
+    void setPrimaryRange(uint32_t minMiplevel, uint32_t maxMiplevel);
+
+    VkImageSubresourceRange getPrimaryViewRange() const { return mPrimaryViewRange; }
+
+    VkImageSubresourceRange getFullViewRange() const { return mFullViewRange; }
+
+    VulkanLayout getPrimaryImageLayout() const {
+        return getLayout(mPrimaryViewRange.baseArrayLayer, mPrimaryViewRange.baseMipLevel);
+    }
+
+    // Gets or creates a cached VkImageView for a single subresource that can be used as a render
+    // target attachment.  Unlike the primary image view, this always has type VK_IMAGE_VIEW_TYPE_2D
+    // and the identity swizzle.
+    VkImageView getAttachmentView(VkImageSubresourceRange range);
+
+    // This is a workaround for the first few frames where we're waiting for the texture to actually
+    // be uploaded.  In that case, we bind the sampler to an empty texture, but the corresponding
+    // imageView needs to be of the right type. Hence, we provide an option to indicate the
+    // view type. Swizzle option does not matter in this case.
+    VkImageView getViewForType(VkImageSubresourceRange const& range, VkImageViewType type);
+
+    VkFormat getVkFormat() const { return mVkFormat; }
+    VkImage getVkImage() const { return mTextureImage; }
+
+    VulkanLayout getLayout(uint32_t layer, uint32_t level) const;
+
+    void setSidecar(VulkanTexture* sidecar) {
+        mSidecarMSAA.reset(sidecar);
+    }
+
+    VulkanTexture* getSidecar() const {
+        return mSidecarMSAA.get();
+    }
+
+    void transitionLayout(VkCommandBuffer commands, const VkImageSubresourceRange& range,
+            VulkanLayout newLayout);
+
+    // Returns the preferred data plane of interest for all image views.
+    // For now this always returns either DEPTH or COLOR.
+    VkImageAspectFlags getImageAspect() const;
+
+    // For implicit transition like the end of a render pass, we need to be able to set the layout
+    // manually (outside of calls to transitionLayout).
+    void setLayout(const VkImageSubresourceRange& range, VulkanLayout newLayout);
+
+#if FVK_ENABLED(FVK_DEBUG_TEXTURE)
+    void print() const;
+#endif
+
+private:

    struct ImageViewKey {
        VkImageSubresourceRange range;  // 4 * 5 bytes
@@ -58,150 +130,6 @@ struct VulkanTextureState : public VulkanResource {

    using ImageViewHash = utils::hash::MurmurHashFn<ImageViewKey>;

-    uint32_t refs = 1;
-
-    // The texture with the sidecar owns the sidecar.
-    std::unique_ptr<VulkanTexture> mSidecarMSAA;
-    VkDeviceMemory mTextureImageMemory = VK_NULL_HANDLE;
-
-    VkFormat const mVkFormat;
-    VkImageViewType const mViewType;
-    VkImageSubresourceRange const mFullViewRange;
-
-    VkImage mTextureImage = VK_NULL_HANDLE;
-
-    // Track the image layout of each subresource using a sparse range map.
-    utils::RangeMap<uint32_t, VulkanLayout> mSubresourceLayouts;
-
-    std::unordered_map<ImageViewKey, VkImageView, ImageViewHash> mCachedImageViews;
-    VulkanStagePool& mStagePool;
-    VkDevice mDevice;
-    VmaAllocator mAllocator;
-    VulkanCommands* mCommands;
-    std::shared_ptr<VulkanCmdFence> mTransitionFence;
-};
-
-
-struct VulkanTexture : public HwTexture, VulkanResource {
-    // Standard constructor for user-facing textures.
-    VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice, VulkanContext const& context,
-            VmaAllocator allocator, VulkanCommands* commands,
-            VulkanResourceAllocator* handleAllocator,
-            SamplerType target, uint8_t levels,
-            TextureFormat tformat, uint8_t samples, uint32_t w, uint32_t h, uint32_t depth,
-            TextureUsage tusage, VulkanStagePool& stagePool, bool heapAllocated = false);
-
-    // Specialized constructor for internally created textures (e.g. from a swap chain)
-    // The texture will never destroy the given VkImage, but it does manages its subresources.
-    VulkanTexture(VkDevice device, VmaAllocator allocator, VulkanCommands* commands,
-            VulkanResourceAllocator* handleAllocator,
-            VkImage image,
-            VkFormat format, uint8_t samples, uint32_t width, uint32_t height, TextureUsage tusage,
-            VulkanStagePool& stagePool, bool heapAllocated = false);
-
-    // Constructor for creating a texture view for wrt specific mip range
-    VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice, VulkanContext const& context,
-            VmaAllocator allocator, VulkanCommands* commands,
-            VulkanResourceAllocator* handleAllocator,
-            VulkanTexture const* src, uint8_t baseLevel, uint8_t levelCount);
-
-    // Constructor for creating a texture view for swizzle.
-    VulkanTexture(VkDevice device, VkPhysicalDevice physicalDevice, VulkanContext const& context,
-            VmaAllocator allocator, VulkanCommands* commands,
-            VulkanResourceAllocator* handleAllocator,
-            VulkanTexture const* src, VkComponentMapping swizzle);
-
-    ~VulkanTexture();
-
-    // Uploads data into a subregion of a 2D or 3D texture.
-    void updateImage(const PixelBufferDescriptor& data, uint32_t width, uint32_t height,
-            uint32_t depth, uint32_t xoffset, uint32_t yoffset, uint32_t zoffset, uint32_t miplevel);
-
-    // Returns the primary image view, which is used for shader sampling.
-    VkImageView getPrimaryImageView() {
-        VulkanTextureState* state = getSharedState();
-        return getImageView(mPrimaryViewRange, state->mViewType, mSwizzle);
-    }
-
-    VkImageViewType getViewType() const {
-        VulkanTextureState const* state = getSharedState();
-        return state->mViewType;
-    }
-
-    VkImageSubresourceRange getPrimaryViewRange() const { return mPrimaryViewRange; }
-
-    VulkanLayout getPrimaryImageLayout() const {
-        return getLayout(mPrimaryViewRange.baseArrayLayer, mPrimaryViewRange.baseMipLevel);
-    }
-
-    // Gets or creates a cached VkImageView for a single subresource that can be used as a render
-    // target attachment.  Unlike the primary image view, this always has type VK_IMAGE_VIEW_TYPE_2D
-    // and the identity swizzle.
-    VkImageView getAttachmentView(VkImageSubresourceRange range);
-
-    // Gets or creates a cached VkImageView for a single subresource that can be used as a render
-    // target attachment when rendering with multiview.
-    VkImageView getMultiviewAttachmentView(VkImageSubresourceRange range);
-
-    // This is a workaround for the first few frames where we're waiting for the texture to actually
-    // be uploaded.  In that case, we bind the sampler to an empty texture, but the corresponding
-    // imageView needs to be of the right type. Hence, we provide an option to indicate the
-    // view type. Swizzle option does not matter in this case.
-    VkImageView getViewForType(VkImageSubresourceRange const& range, VkImageViewType type);
-
-    VkFormat getVkFormat() const {
-        VulkanTextureState const* state = getSharedState();
-        return state->mVkFormat;
-    }
-    VkImage getVkImage() const {
-        VulkanTextureState const* state = getSharedState();
-        return state->mTextureImage;
-    }
-
-    VulkanLayout getLayout(uint32_t layer, uint32_t level) const;
-
-    void setSidecar(VulkanTexture* sidecar) {
-        VulkanTextureState* state = getSharedState();
-        state->mSidecarMSAA.reset(sidecar);
-    }
-
-    VulkanTexture* getSidecar() const {
-        VulkanTextureState const* state = getSharedState();
-        return state->mSidecarMSAA.get();
-    }
-
-    bool transitionLayout(VulkanCommandBuffer* commands, const VkImageSubresourceRange& range,
-            VulkanLayout newLayout);
-
-    bool transitionLayout(VkCommandBuffer cmdbuf, std::shared_ptr<VulkanCmdFence> fence,
-            VkImageSubresourceRange const& range, VulkanLayout newLayout);
-
-    void attachmentToSamplerBarrier(VulkanCommandBuffer* commands,
-            VkImageSubresourceRange const& range);
-
-    // Returns the preferred data plane of interest for all image views.
-    // For now this always returns either DEPTH or COLOR.
-    VkImageAspectFlags getImageAspect() const;
-
-    // For implicit transition like the end of a render pass, we need to be able to set the layout
-    // manually (outside of calls to transitionLayout).
-    void setLayout(VkImageSubresourceRange const& range, VulkanLayout newLayout);
-
-    bool transitionReady() {
-        VulkanTextureState* state = getSharedState();
-        auto res = !state->mTransitionFence || state->mTransitionFence->getStatus() == VK_SUCCESS;
-        state->mTransitionFence.reset();
-        return res;
-    }
-
-#if FVK_ENABLED(FVK_DEBUG_TEXTURE)
-    void print() const;
-#endif
-
-private:
-    VulkanTextureState* getSharedState();
-    VulkanTextureState const* getSharedState() const;
-
    // Gets or creates a cached VkImageView for a range of miplevels, array layers, viewType, and
    // swizzle (or not).
    VkImageView getImageView(VkImageSubresourceRange range, VkImageViewType viewType,
@@ -210,15 +138,28 @@ private:
    void updateImageWithBlit(const PixelBufferDescriptor& hostData, uint32_t width, uint32_t height,
            uint32_t depth, uint32_t miplevel);

-    VulkanResourceAllocator* const mAllocator;
+    // The texture with the sidecar owns the sidecar.
+    std::unique_ptr<VulkanTexture> mSidecarMSAA;
+    const VkFormat mVkFormat;
+    const VkImageViewType mViewType;
+    const VkComponentMapping mSwizzle;
+    VkImage mTextureImage = VK_NULL_HANDLE;
+    VkDeviceMemory mTextureImageMemory = VK_NULL_HANDLE;

-    Handle<VulkanTextureState> mState;
+    // Track the image layout of each subresource using a sparse range map.
+    utils::RangeMap<uint32_t, VulkanLayout> mSubresourceLayouts;
+
+    VkImageSubresourceRange mFullViewRange;

    // Track the range of subresources that define the "primary" image view, which is the special
    // image view that gets bound to an actual texture sampler.
    VkImageSubresourceRange mPrimaryViewRange;

-    VkComponentMapping mSwizzle {};
+    std::unordered_map<ImageViewKey, VkImageView, ImageViewHash> mCachedImageViews;
+    VulkanStagePool& mStagePool;
+    VkDevice mDevice;
+    VmaAllocator mAllocator;
+    VulkanCommands* mCommands;
 };

 } // namespace filament::backend
--- a/filament/backend/src/vulkan/VulkanUtility.cpp
+++ b/filament/backend/src/vulkan/VulkanUtility.cpp
@@ -577,7 +577,7 @@ uint32_t getComponentCount(VkFormat format) {
    return {};
 }

-VkComponentMapping getSwizzleMap(TextureSwizzle const swizzle[4]) {
+VkComponentMapping getSwizzleMap(TextureSwizzle swizzle[4]) {
    VkComponentMapping map;
    VkComponentSwizzle* dst = &map.r;
    for (int i = 0; i < 4; ++i, ++dst) {
--- a/filament/backend/src/vulkan/VulkanUtility.h
+++ b/filament/backend/src/vulkan/VulkanUtility.h
@@ -19,7 +19,6 @@

 #include <backend/DriverEnums.h>

-#include <utils/bitset.h>
 #include <utils/FixedCapacityVector.h>

 #include <bluevk/BlueVK.h>
@@ -39,7 +38,7 @@ VkCullModeFlags getCullMode(CullingMode mode);
 VkFrontFace getFrontFace(bool inverseFrontFaces);
 PixelDataType getComponentType(VkFormat format);
 uint32_t getComponentCount(VkFormat format);
-VkComponentMapping getSwizzleMap(TextureSwizzle const swizzle[4]);
+VkComponentMapping getSwizzleMap(TextureSwizzle swizzle[4]);
 VkShaderStageFlags getShaderStageFlags(ShaderStageFlags stageFlags);

 bool equivalent(const VkRect2D& a, const VkRect2D& b);
@@ -406,13 +405,12 @@ constexpr VkFormat ALL_VK_FORMATS[] = {
        VK_FORMAT_R16G16_S10_5_NV,
 };

-// An Array that will be statically fixed in capacity, but the "size" (as in user added elements) is
-// variable. Note that this class is movable.
+// An Array that will be fixed capacity, but the "size" (as in user added elements) is variable.
+// Note that this class is movable.
 template<typename T, uint16_t CAPACITY>
 class CappedArray {
 private:
    using FixedSizeArray = std::array<T, CAPACITY>;
-
 public:
    using const_iterator = typename FixedSizeArray::const_iterator;
    using iterator = typename FixedSizeArray::iterator;
@@ -450,20 +448,6 @@ public:
        return mArray.cend();
    }

-    inline iterator begin() {
-        if (mInd == 0) {
-            return mArray.end();
-        }
-        return mArray.begin();
-    }
-
-    inline iterator end() {
-        if (mInd > 0 && mInd < CAPACITY) {
-            return mArray.begin() + mInd;
-        }
-        return mArray.end();
-    }
-
    inline T back() {
        assert_invariant(mInd > 0);
        return *(mArray.begin() + mInd);
@@ -528,28 +512,125 @@ private:
    uint32_t mInd = 0;
 };

-using UniformBufferBitmask = utils::bitset64;
-using SamplerBitmask = utils::bitset64;
+// TODO: ok to remove once Filament-side API is complete
+namespace descset {
+
+// Used to describe the descriptor binding in shader stages. We assume that the binding index does
+// not exceed 31. We also assume that we have two shader stages - vertex and fragment.  The below
+// types and struct are used across VulkanDescriptorSet and VulkanProgram.
+using UniformBufferBitmask = uint32_t;
+using SamplerBitmask = uint64_t;

 // We only have at most one input attachment, so this bitmask exists only to make the code more
 // general.
-using InputAttachmentBitmask = utils::bitset64;
+using InputAttachmentBitmask = uint8_t;
+
+constexpr UniformBufferBitmask UBO_VERTEX_STAGE = 0x1;
+constexpr UniformBufferBitmask UBO_FRAGMENT_STAGE = (0x1ULL << (sizeof(UniformBufferBitmask) * 4));
+constexpr SamplerBitmask SAMPLER_VERTEX_STAGE = 0x1;
+constexpr SamplerBitmask SAMPLER_FRAGMENT_STAGE = (0x1ULL << (sizeof(SamplerBitmask) * 4));
+constexpr InputAttachmentBitmask INPUT_ATTACHMENT_VERTEX_STAGE = 0x1;
+constexpr InputAttachmentBitmask INPUT_ATTACHMENT_FRAGMENT_STAGE =
+        (0x1ULL << (sizeof(InputAttachmentBitmask) * 4));

 template<typename Bitmask>
-static constexpr uint8_t getVertexStageShift() noexcept {
-    // We assume the bottom half of bits are for vertex stages.
-    return 0;
+static constexpr Bitmask getVertexStage() noexcept {
+    if constexpr (std::is_same_v<Bitmask, UniformBufferBitmask>) {
+        return UBO_VERTEX_STAGE;
+    }
+    if constexpr (std::is_same_v<Bitmask, SamplerBitmask>) {
+        return SAMPLER_VERTEX_STAGE;
+    }
+    if constexpr (std::is_same_v<Bitmask, InputAttachmentBitmask>) {
+        return INPUT_ATTACHMENT_VERTEX_STAGE;
+    }
 }

 template<typename Bitmask>
-static constexpr uint8_t getFragmentStageShift() noexcept {
-    // We assume the top half of bits are for fragment stages.
-    return sizeof(Bitmask) * 4;
+static constexpr Bitmask getFragmentStage() noexcept {
+    if constexpr (std::is_same_v<Bitmask, UniformBufferBitmask>) {
+        return UBO_FRAGMENT_STAGE;
+    }
+    if constexpr (std::is_same_v<Bitmask, SamplerBitmask>) {
+        return SAMPLER_FRAGMENT_STAGE;
+    }
+    if constexpr (std::is_same_v<Bitmask, InputAttachmentBitmask>) {
+        return INPUT_ATTACHMENT_FRAGMENT_STAGE;
+    }
 }

-// We have at most 4 descriptor sets. This is to indicate which ones are active.
-using DescriptorSetMask = utils::bitset8;
+typedef enum ShaderStageFlags2 : uint8_t {
+    NONE        =    0,
+    VERTEX      =    0x1,
+    FRAGMENT    =    0x2,
+} ShaderStageFlags2;

+enum class DescriptorType : uint8_t {
+    UNIFORM_BUFFER,
+    SAMPLER,
+    INPUT_ATTACHMENT,
+};
+
+enum class DescriptorFlags : uint8_t {
+    NONE = 0x00,
+    DYNAMIC_OFFSET = 0x01
+};
+
+struct DescriptorSetLayoutBinding {
+    DescriptorType type;
+    ShaderStageFlags2 stageFlags;
+    uint8_t binding;
+    DescriptorFlags flags;
+    uint16_t count;
+};
+
+struct DescriptorSetLayout {
+    utils::FixedCapacityVector<DescriptorSetLayoutBinding> bindings;
+};
+
+} // namespace descset
+
+namespace {
+// Use constexpr to statically generate a bit count table for 8-bit numbers.
+struct _BitCountHelper {
+    constexpr _BitCountHelper() : data{} {
+        for (uint16_t i = 0; i < 256; ++i) {
+            data[i] = 0;
+            for (auto j = i; j > 0; j /= 2) {
+                if (j & 1) {
+                    data[i]++;
+                }
+            }
+        }
+    }
+
+    template<typename MaskType>
+    constexpr uint8_t count(MaskType num) {
+        uint8_t count = 0;
+        for (uint8_t i = 0; i < sizeof(MaskType) * 8; i+=8) {
+            count += data[(num >> i) & 0xFF];
+        }
+        return count;
+    }
+
+private:
+    uint8_t data[256];
+};
+} // namespace anonymous
+
+template<typename MaskType>
+inline uint8_t countBits(MaskType num) {
+    static _BitCountHelper BitCounter = {};
+    return BitCounter.count(num);
+}
+
+// This is useful for counting the total number of descriptors for both vertex and fragment stages.
+template<typename MaskType>
+inline MaskType collapseStages(MaskType mask) {
+    constexpr uint8_t NBITS_DIV_2 = sizeof(MaskType) * 4;
+    // First zero out the top-half and then or the bottom-half against the original top-half.
+    return ((mask << NBITS_DIV_2) >> NBITS_DIV_2) | (mask >> NBITS_DIV_2);
+}

 } // namespace filament::backend

--- a/filament/backend/src/vulkan/caching/VulkanDescriptorSetManager.cpp
+++ b/filament/backend/src/vulkan/caching/VulkanDescriptorSetManager.cpp
--- a/filament/backend/src/vulkan/caching/VulkanDescriptorSetManager.h
+++ b/filament/backend/src/vulkan/caching/VulkanDescriptorSetManager.h
@@ -30,8 +30,12 @@
 #include <bluevk/BlueVK.h>
 #include <tsl/robin_map.h>

+#include <functional>
+
 namespace filament::backend {

+using namespace descset;
+
 // [GDSR]: Great-Descriptor-Set-Refactor: As of 03/20/24, the Filament frontend is planning to
 // introduce descriptor set. This PR will arrive before that change is complete. As such, some of
 // the methods introduced here will be obsolete, and certain logic will be generalized.
@@ -41,32 +45,60 @@ class VulkanDescriptorSetManager {
 public:
    static constexpr uint8_t UNIQUE_DESCRIPTOR_SET_COUNT =
            VulkanDescriptorSetLayout::UNIQUE_DESCRIPTOR_SET_COUNT;
-
-    using DescriptorSetLayoutArray = VulkanDescriptorSetLayout::DescriptorSetLayoutArray;
+    using GetPipelineLayoutFunction = std::function<VkPipelineLayout(
+            VulkanDescriptorSetLayoutList const&, VulkanProgram* program)>;

    VulkanDescriptorSetManager(VkDevice device, VulkanResourceAllocator* resourceAllocator);

    void terminate() noexcept;

-    void updateBuffer(VulkanDescriptorSet* set, uint8_t binding,
+    void gc();
+
+    // TODO: Obsolete after [GDSR].
+    // This will write/update/bind all of the descriptor set. After [GDSR], the binding for
+    // descriptor sets will not depend on the layout described in the program.
+    VkPipelineLayout bind(VulkanCommandBuffer* commands, VulkanProgram* program,
+            GetPipelineLayoutFunction& getPipelineLayoutFn);
+
+    // TODO: Obsolete after [GDSR].
+    // This is to "dynamically" bind UBOs that might have offsets changed between pipeline binding
+    // and the draw call. We do this because UBOs for primitives that are part of the same
+    // renderable can be stored within one buffer. This can be a no-op if there were no range
+    // changes between the pipeline bind and the draw call. We will re-use applicable states
+    // provided within the bind() call, including the UBO descriptor set layout. TODO: make it a
+    // proper dynamic binding when Filament-side descriptor changes are completed.
+    void dynamicBind(VulkanCommandBuffer* commands, Handle<VulkanDescriptorSetLayout> uboLayout);
+
+    // TODO: Obsolete after [GDSR].
+    // Since we use program pointer as cache key, we need to clear the cache when it's freed.
+    void clearProgram(VulkanProgram* program) noexcept;
+
+    Handle<VulkanDescriptorSetLayout> createLayout(descset::DescriptorSetLayout const& layout);
+
+    void destroyLayout(Handle<VulkanDescriptorSetLayout> layout);
+
+    void updateBuffer(Handle<VulkanDescriptorSet> set, uint8_t binding,
            VulkanBufferObject* bufferObject, VkDeviceSize offset, VkDeviceSize size) noexcept;

-    void updateSampler(VulkanDescriptorSet* set, uint8_t binding,
+    void updateSampler(Handle<VulkanDescriptorSet> set, uint8_t binding,
            VulkanTexture* texture, VkSampler sampler) noexcept;

-    void updateInputAttachment(VulkanDescriptorSet* set, VulkanAttachment attachment) noexcept;
+    void updateInputAttachment(Handle<VulkanDescriptorSet> set, VulkanAttachment attachment) noexcept;

-    void bind(uint8_t setIndex, VulkanDescriptorSet* set, backend::DescriptorSetOffsetArray&& offsets);
-
-    void commit(VulkanCommandBuffer* commands, VkPipelineLayout pipelineLayout,
-            DescriptorSetMask const& setMask);
+    void clearBuffer(uint32_t bindingIndex);

    void setPlaceHolders(VkSampler sampler, VulkanTexture* texture,
            VulkanBufferObject* bufferObject) noexcept;

-    void createSet(Handle<HwDescriptorSet> handle, VulkanDescriptorSetLayout* layout);
+    void clearState() noexcept;

-    void destroySet(Handle<HwDescriptorSet> handle);
+    // TODO: To be completed after [GDSR]
+    Handle<VulkanDescriptorSet> createSet(Handle<VulkanDescriptorSetLayout> layout) {
+        return Handle<VulkanDescriptorSet>();
+    }
+
+    // TODO: To be completed after [GDSR]
+    void destroySet(Handle<VulkanDescriptorSet> set) {}

 private:
    class Impl;
@@ -76,3 +108,4 @@ private:
 }// namespace filament::backend

 #endif// TNT_FILAMENT_BACKEND_CACHING_VULKANDESCRIPTORSETMANAGER_H
+
--- a/filament/backend/src/vulkan/caching/VulkanPipelineLayoutCache.cpp
+++ b/filament/backend/src/vulkan/caching/VulkanPipelineLayoutCache.cpp
@@ -21,20 +21,19 @@
 namespace filament::backend {

 VkPipelineLayout VulkanPipelineLayoutCache::getLayout(
-        DescriptorSetLayoutArray const& descriptorSetLayouts, VulkanProgram* program) {
+        VulkanDescriptorSetLayoutList const& descriptorSetLayouts, VulkanProgram* program) {
    PipelineLayoutKey key = {};
    uint8_t descSetLayoutCount = 0;
-    key.descSetLayouts = descriptorSetLayouts;
    for (auto layoutHandle: descriptorSetLayouts) {
-        if (layoutHandle == VK_NULL_HANDLE) {
-            break;
+        if (layoutHandle) {
+            auto layout = mAllocator->handle_cast<VulkanDescriptorSetLayout*>(layoutHandle);
+            key.descSetLayouts[descSetLayoutCount++] = layout->vklayout;
        }
-        descSetLayoutCount++;
    }

    // build the push constant layout key
-    uint32_t const pushConstantRangeCount = program->getPushConstantRangeCount();
-    auto const& pushConstantRanges = program->getPushConstantRanges();
+    uint32_t pushConstantRangeCount = program->getPushConstantRangeCount();
+    auto const& pushConstantRanges = program->getPushConstantRanges();    
    if (pushConstantRangeCount > 0) {
        assert_invariant(pushConstantRangeCount <= Program::SHADER_TYPE_COUNT);
        for (uint8_t i = 0; i < pushConstantRangeCount; ++i) {
@@ -53,8 +52,8 @@ VkPipelineLayout VulkanPipelineLayoutCache::getLayout(
        }
    }

-    if (auto iter = mPipelineLayouts.find(key); iter != mPipelineLayouts.end()) {
-        PipelineLayoutCacheEntry& entry = iter->second;
+    if (PipelineLayoutMap::iterator iter = mPipelineLayouts.find(key); iter != mPipelineLayouts.end()) {
+        PipelineLayoutCacheEntry& entry = iter.value();
        entry.lastUsed = mTimestamp++;
        return entry.handle;
    }
--- a/filament/backend/src/vulkan/caching/VulkanPipelineLayoutCache.h
+++ b/filament/backend/src/vulkan/caching/VulkanPipelineLayoutCache.h
@@ -22,40 +22,41 @@

 #include <utils/Hash.h>

-#include <unordered_map>
+#include <tsl/robin_map.h>

 namespace filament::backend {

 class VulkanPipelineLayoutCache {
 public:
-    using DescriptorSetLayoutArray = VulkanDescriptorSetLayout::DescriptorSetLayoutArray;
-    
    VulkanPipelineLayoutCache(VkDevice device, VulkanResourceAllocator* allocator)
        : mDevice(device),
+          mAllocator(allocator),
          mTimestamp(0) {}

    void terminate() noexcept;

    struct PushConstantKey {
-        uint8_t stage = 0;// We have one set of push constant per shader stage (fragment, vertex, etc).
-        uint8_t size = 0;
+        uint8_t stage;// We have one set of push constant per shader stage (fragment, vertex, etc).
+        uint8_t size;
        // Note that there is also an offset parameter for push constants, but
        // we always assume our update range will have the offset 0.
    };

    struct PipelineLayoutKey {
-        DescriptorSetLayoutArray descSetLayouts = {};                                     // 8 * 4
-        PushConstantKey pushConstant[Program::SHADER_TYPE_COUNT] = {};                    // 2 * 3
+        using DescriptorSetLayoutArray = std::array<VkDescriptorSetLayout,
+                VulkanDescriptorSetLayout::UNIQUE_DESCRIPTOR_SET_COUNT>;
+        DescriptorSetLayoutArray descSetLayouts = {};                   // 8 * 3
+        PushConstantKey pushConstant[Program::SHADER_TYPE_COUNT] = {};  // 2 * 3
        uint16_t padding = 0;
    };
-    static_assert(sizeof(PipelineLayoutKey) == 40);
+    static_assert(sizeof(PipelineLayoutKey) == 32);

    VulkanPipelineLayoutCache(VulkanPipelineLayoutCache const&) = delete;
    VulkanPipelineLayoutCache& operator=(VulkanPipelineLayoutCache const&) = delete;

    // A pipeline layout depends on the descriptor set layout and the push constant ranges, which
    // are described in the program.
-    VkPipelineLayout getLayout(DescriptorSetLayoutArray const& descriptorSetLayouts,
+    VkPipelineLayout getLayout(VulkanDescriptorSetLayoutList const& descriptorSetLayouts,
            VulkanProgram* program);

 private:
@@ -72,14 +73,15 @@ private:
        }
    };

-    using PipelineLayoutMap = std::unordered_map<PipelineLayoutKey, PipelineLayoutCacheEntry,
+    using PipelineLayoutMap = tsl::robin_map<PipelineLayoutKey, PipelineLayoutCacheEntry,
            PipelineLayoutKeyHashFn, PipelineLayoutKeyEqual>;

    VkDevice mDevice;
+    VulkanResourceAllocator* mAllocator;
    Timestamp mTimestamp;
    PipelineLayoutMap mPipelineLayouts;
 };

-} // filament::backend
+}

 #endif // TNT_FILAMENT_BACKEND_VULKANPIPELINECACHE_H
--- a/filament/backend/src/vulkan/platform/VulkanPlatform.cpp
+++ b/filament/backend/src/vulkan/platform/VulkanPlatform.cpp
@@ -325,7 +325,6 @@ VkDevice createLogicalDevice(VkPhysicalDevice physicalDevice,
    // We could simply enable all supported features, but since that may have performance
    // consequences let's just enable the features we need.
    VkPhysicalDeviceFeatures enabledFeatures{
-            .depthClamp = features.depthClamp,
            .samplerAnisotropy = features.samplerAnisotropy,
            .textureCompressionETC2 = features.textureCompressionETC2,
            .textureCompressionBC = features.textureCompressionBC,
--- a/filament/backend/test/BackendTest.cpp
+++ b/filament/backend/test/BackendTest.cpp
@@ -112,10 +112,9 @@ void BackendTest::fullViewport(Viewport& viewport) {
 }

 void BackendTest::renderTriangle(
-        PipelineLayout const& pipelineLayout,
-        Handle<filament::backend::HwRenderTarget> renderTarget,
-        Handle<filament::backend::HwSwapChain> swapChain,
-        Handle<filament::backend::HwProgram> program) {
+        filament::backend::Handle<filament::backend::HwRenderTarget> renderTarget,
+        filament::backend::Handle<filament::backend::HwSwapChain> swapChain,
+        filament::backend::Handle<filament::backend::HwProgram> program) {
    RenderPassParams params = {};
    fullViewport(params);
    params.flags.clear = TargetBufferFlags::COLOR;
@@ -124,15 +123,11 @@ void BackendTest::renderTriangle(
    params.flags.discardEnd = TargetBufferFlags::NONE;
    params.viewport.height = 512;
    params.viewport.width = 512;
-    renderTriangle(pipelineLayout, renderTarget, swapChain, program, params);
+    renderTriangle(renderTarget, swapChain, program, params);
 }

-void BackendTest::renderTriangle(
-        PipelineLayout const& pipelineLayout,
-        Handle<HwRenderTarget> renderTarget,
-        Handle<HwSwapChain> swapChain,
-        Handle<HwProgram> program,
-        const RenderPassParams& params) {
+void BackendTest::renderTriangle(Handle<HwRenderTarget> renderTarget,
+        Handle<HwSwapChain> swapChain, Handle<HwProgram> program, const RenderPassParams& params) {
    auto& api = getDriverApi();

    TrianglePrimitive triangle(api);
@@ -143,7 +138,6 @@ void BackendTest::renderTriangle(

    PipelineState state;
    state.program = program;
-    state.pipelineLayout = pipelineLayout;
    state.rasterState.colorWrite = true;
    state.rasterState.depthWrite = false;
    state.rasterState.depthFunc = RasterState::DepthFunc::A;
--- a/filament/backend/test/BackendTest.h
+++ b/filament/backend/test/BackendTest.h
@@ -51,15 +51,10 @@ protected:
    static void fullViewport(filament::backend::RenderPassParams& params);
    static void fullViewport(filament::backend::Viewport& viewport);

-    void renderTriangle(
-            filament::backend::PipelineLayout const& pipelineLayout,
-            filament::backend::Handle<filament::backend::HwRenderTarget> renderTarget,
+    void renderTriangle(filament::backend::Handle<filament::backend::HwRenderTarget> renderTarget,
            filament::backend::Handle<filament::backend::HwSwapChain> swapChain,
            filament::backend::Handle<filament::backend::HwProgram> program);
-
-    void renderTriangle(
-            filament::backend::PipelineLayout const& pipelineLayout,
-            filament::backend::Handle<filament::backend::HwRenderTarget> renderTarget,
+    void renderTriangle(filament::backend::Handle<filament::backend::HwRenderTarget> renderTarget,
            filament::backend::Handle<filament::backend::HwSwapChain> swapChain,
            filament::backend::Handle<filament::backend::HwProgram> program,
            const filament::backend::RenderPassParams& params);
--- a/filament/backend/test/MetalTest.mm
+++ b/filament/backend/test/MetalTest.mm
@@ -1,159 +0,0 @@
-/*
- * Copyright (C) 2024 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <gtest/gtest.h>
-
-#include "../src/metal/MetalContext.h"
-
-namespace test {
-
-TEST(MetalDynamicOffsets, none) {
-    filament::backend::MetalDynamicOffsets dynamicOffsets;
-    const auto [count, offsets] = dynamicOffsets.getOffsets();
-    EXPECT_EQ(count, 0u);
-}
-
-TEST(MetalDynamicOffsets, basic) {
-    filament::backend::MetalDynamicOffsets dynamicOffsets;
-    {
-        const auto [count, offsets] = dynamicOffsets.getOffsets();
-        EXPECT_EQ(count, 0u);
-    }
-
-    {
-        uint32_t o[2] = { 1, 2 };
-        dynamicOffsets.setOffsets(0, o, 2);
-        const auto [count, offsets] = dynamicOffsets.getOffsets();
-        EXPECT_EQ(count, 2);
-        EXPECT_EQ(offsets[0], 1);
-        EXPECT_EQ(offsets[1], 2);
-    }
-
-    {
-        uint32_t o[3] = { 3, 4, 5 };
-        dynamicOffsets.setOffsets(1, o, 3);
-        const auto [count, offsets] = dynamicOffsets.getOffsets();
-        EXPECT_EQ(count, 5);
-        EXPECT_EQ(offsets[0], 1);
-        EXPECT_EQ(offsets[1], 2);
-        EXPECT_EQ(offsets[2], 3);
-        EXPECT_EQ(offsets[3], 4);
-        EXPECT_EQ(offsets[4], 5);
-    }
-
-    // skip descriptor set index 2
-
-    {
-        uint32_t o[1] = { 6 };
-        dynamicOffsets.setOffsets(3, o, 1);
-        const auto [count, offsets] = dynamicOffsets.getOffsets();
-        EXPECT_EQ(count, 6);
-        EXPECT_EQ(offsets[0], 1);
-        EXPECT_EQ(offsets[1], 2);
-        EXPECT_EQ(offsets[2], 3);
-        EXPECT_EQ(offsets[3], 4);
-        EXPECT_EQ(offsets[4], 5);
-        EXPECT_EQ(offsets[5], 6);
-    }
-}
-
-TEST(MetalDynamicOffsets, outOfOrder) {
-    filament::backend::MetalDynamicOffsets dynamicOffsets;
-    uint32_t o1[2] = { 2, 3 };
-    dynamicOffsets.setOffsets(1, o1, 2);
-    uint32_t o2[2] = { 0, 1 };
-    dynamicOffsets.setOffsets(0, o2, 2);
-    uint32_t o3[2] = { 4, 5 };
-    dynamicOffsets.setOffsets(2, o3, 2);
-
-    const auto [count, offsets] = dynamicOffsets.getOffsets();
-    EXPECT_EQ(count, 6);
-    EXPECT_EQ(offsets[0], 0);
-    EXPECT_EQ(offsets[1], 1);
-    EXPECT_EQ(offsets[2], 2);
-    EXPECT_EQ(offsets[3], 3);
-    EXPECT_EQ(offsets[4], 4);
-    EXPECT_EQ(offsets[5], 5);
-};
-
-TEST(MetalDynamicOffsets, removal) {
-    filament::backend::MetalDynamicOffsets dynamicOffsets;
-    uint32_t o1[2] = { 2, 3 };
-    dynamicOffsets.setOffsets(1, o1, 2);
-    uint32_t o2[2] = { 0, 1 };
-    dynamicOffsets.setOffsets(0, o2, 2);
-    uint32_t o3[2] = { 4, 5 };
-    dynamicOffsets.setOffsets(2, o3, 2);
-    dynamicOffsets.setOffsets(1, nullptr, 0);
-
-    const auto [count, offsets] = dynamicOffsets.getOffsets();
-    EXPECT_EQ(count, 4);
-    EXPECT_EQ(offsets[0], 0);
-    EXPECT_EQ(offsets[1], 1);
-    EXPECT_EQ(offsets[2], 4);
-    EXPECT_EQ(offsets[3], 5);
-};
-
-TEST(MetalDynamicOffsets, resize) {
-    filament::backend::MetalDynamicOffsets dynamicOffsets;
-    uint32_t o1[2] = { 2, 3 };
-    dynamicOffsets.setOffsets(1, o1, 2);
-    uint32_t o2[2] = { 0, 1 };
-    dynamicOffsets.setOffsets(0, o2, 2);
-    uint32_t o3[2] = { 6, 7 };
-    dynamicOffsets.setOffsets(2, o3, 2);
-    uint32_t o4[4] = { 2, 3, 4, 5 };
-    dynamicOffsets.setOffsets(1, o4, 4);
-
-    const auto [count, offsets] = dynamicOffsets.getOffsets();
-    EXPECT_EQ(count, 8);
-    EXPECT_EQ(offsets[0], 0);
-    EXPECT_EQ(offsets[1], 1);
-    EXPECT_EQ(offsets[2], 2);
-    EXPECT_EQ(offsets[3], 3);
-    EXPECT_EQ(offsets[4], 4);
-    EXPECT_EQ(offsets[5], 5);
-    EXPECT_EQ(offsets[6], 6);
-    EXPECT_EQ(offsets[7], 7);
-};
-
-TEST(MetalDynamicOffsets, dirty) {
-    filament::backend::MetalDynamicOffsets dynamicOffsets;
-    EXPECT_FALSE(dynamicOffsets.isDirty());
-
-    uint32_t o1[2] = { 2, 3 };
-    dynamicOffsets.setOffsets(1, o1, 2);
-    EXPECT_TRUE(dynamicOffsets.isDirty());
-
-    dynamicOffsets.setDirty(false);
-    EXPECT_FALSE(dynamicOffsets.isDirty());
-
-    // Setting the same offsets should not mark the offsets as dirty
-    dynamicOffsets.setOffsets(1, o1, 2);
-    EXPECT_FALSE(dynamicOffsets.isDirty());
-
-    // Resizing the offsets should mark the offsets as dirty
-    uint32_t o2[3] = { 4, 5, 6 };
-    dynamicOffsets.setOffsets(1, o2, 3);
-    EXPECT_TRUE(dynamicOffsets.isDirty());
-};
-
-};
-
-int main(int argc, char **argv) {
-    testing::InitGoogleTest(&argc, argv);
-    return RUN_ALL_TESTS();
-}
--- a/filament/backend/test/ShaderGenerator.cpp
+++ b/filament/backend/test/ShaderGenerator.cpp
@@ -73,13 +73,12 @@ void ShaderGenerator::shutdown() {
    FinalizeProcess();
 }

-ShaderGenerator::ShaderGenerator(std::string vertex, std::string fragment, Backend backend,
-        bool isMobile, filamat::DescriptorSets&& descriptorSets) noexcept
-    : mBackend(backend),
-      mVertexBlob(transpileShader(
-              ShaderStage::VERTEX, std::move(vertex), backend, isMobile, descriptorSets)),
-      mFragmentBlob(transpileShader(
-              ShaderStage::FRAGMENT, std::move(fragment), backend, isMobile, descriptorSets)) {
+ShaderGenerator::ShaderGenerator(std::string vertex, std::string fragment,
+        Backend backend, bool isMobile, const filament::SamplerInterfaceBlock* sib) noexcept
+        : mBackend(backend),
+          mVertexBlob(transpileShader(ShaderStage::VERTEX, std::move(vertex), backend, isMobile, sib)),
+          mFragmentBlob(transpileShader(ShaderStage::FRAGMENT, std::move(fragment), backend,
+                  isMobile, sib)) {
    switch (backend) {
        case Backend::OPENGL:
            mShaderLanguage = filament::backend::ShaderLanguage::ESSL3;
@@ -96,8 +95,9 @@ ShaderGenerator::ShaderGenerator(std::string vertex, std::string fragment, Backe
    }
 }

-ShaderGenerator::Blob ShaderGenerator::transpileShader(ShaderStage stage, std::string shader,
-        Backend backend, bool isMobile, const filamat::DescriptorSets& descriptorSets) noexcept {
+ShaderGenerator::Blob ShaderGenerator::transpileShader(
+        ShaderStage stage, std::string shader, Backend backend, bool isMobile,
+        const filament::SamplerInterfaceBlock* sib) noexcept {
    TProgram program;
    const EShLanguage language = stage == ShaderStage::VERTEX ? EShLangVertex : EShLangFragment;
    TShader tShader(language);
@@ -161,8 +161,9 @@ ShaderGenerator::Blob ShaderGenerator::transpileShader(ShaderStage stage, std::s
        return { result.c_str(), result.c_str() + result.length() + 1 };
    } else if (backend == Backend::METAL) {
        const auto sm = isMobile ? ShaderModel::MOBILE : ShaderModel::DESKTOP;
-        filamat::GLSLPostProcessor::spirvToMsl(
-                &spirv, &result, stage, sm, false, descriptorSets, nullptr);
+        filamat::SibVector sibs = filamat::SibVector::with_capacity(1);
+        if (sib) { sibs.emplace_back(0, sib); }
+        filamat::GLSLPostProcessor::spirvToMsl(&spirv, &result, sm, false, sibs, nullptr);
        return { result.c_str(), result.c_str() + result.length() + 1 };
    } else if (backend == Backend::VULKAN) {
        return { (uint8_t*)spirv.data(), (uint8_t*)(spirv.data() + spirv.size()) };
--- a/filament/backend/test/ShaderGenerator.h
+++ b/filament/backend/test/ShaderGenerator.h
@@ -22,7 +22,6 @@
 #include "private/filament/SamplerInterfaceBlock.h"
 #include "private/backend/DriverApi.h"
 #include "backend/Program.h"
-#include "../src/GLSLPostProcessor.h"

 #include <string>

@@ -41,7 +40,7 @@ public:
     * @param fragment The fragment shader, written in GLSL 450 core.
     */
    ShaderGenerator(std::string vertex, std::string fragment, Backend backend, bool isMobile,
-            filamat::DescriptorSets&& descriptorSets = {}) noexcept;
+            const filament::SamplerInterfaceBlock* sib = nullptr) noexcept;

    ShaderGenerator(const ShaderGenerator& rhs) = delete;
    ShaderGenerator& operator=(const ShaderGenerator& rhs) = delete;
@@ -53,7 +52,7 @@ private:

    using Blob = std::vector<char>;
    static Blob transpileShader(ShaderStage stage, std::string shader, Backend backend,
-            bool isMobile, const filamat::DescriptorSets& descriptorSets) noexcept;
+            bool isMobile, const filament::SamplerInterfaceBlock* sib = nullptr) noexcept;

    Backend mBackend;

--- a/filament/backend/test/mac_runner.mm
+++ b/filament/backend/test/mac_runner.mm
@@ -53,7 +53,8 @@ test::NativeView getNativeView() {
    nativeView.width = static_cast<size_t>(drawableSize.width);
    nativeView.height = static_cast<size_t>(drawableSize.height);

-    exit(test::runTests());
+    test::runTests();
+    // exit(runTests());
 }

 - (NSView*)createView {
--- a/filament/backend/test/test_Blit.cpp
+++ b/filament/backend/test/test_Blit.cpp
@@ -38,7 +38,7 @@ using namespace utils;

 static const char* const triangleVs = R"(#version 450 core
 layout(location = 0) in vec4 mesh_position;
-layout(binding = 0, set = 1) uniform Params { highp vec4 color; highp vec4 scale; } params;
+uniform Params { highp vec4 color; highp vec4 scale; } params;
 void main() {
    gl_Position = vec4((mesh_position.xy + 0.5) * params.scale.xy, params.scale.z, 1.0);
 #if defined(TARGET_VULKAN_ENVIRONMENT)
@@ -50,7 +50,7 @@ void main() {
 static const char* const triangleFs = R"(#version 450 core
 precision mediump int; precision highp float;
 layout(location = 0) out vec4 fragColor;
-layout(binding = 0, set = 1) uniform Params { highp vec4 color; highp vec4 scale; } params;
+uniform Params { highp vec4 color; highp vec4 scale; } params;
 void main() {
    fragColor = params.color;
 })";
@@ -348,26 +348,12 @@ TEST_F(BackendTest, ColorResolve) {
    // Create a program.
    ProgramHandle program;
    {
-        filamat::DescriptorSets descriptors;
-        descriptors[1] = { { "Params",
-                { DescriptorType::UNIFORM_BUFFER, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0 },
-                {} } };
-        ShaderGenerator shaderGen(
-                triangleVs, triangleFs, sBackend, sIsMobilePlatform, std::move(descriptors));
+        ShaderGenerator shaderGen(triangleVs, triangleFs, sBackend, sIsMobilePlatform);
        Program prog = shaderGen.getProgram(api);
-        prog.descriptorBindings(1, {{ "Params", DescriptorType::UNIFORM_BUFFER, 0 }});
+        prog.uniformBlockBindings({{"params", 1}});
        program = api.createProgram(std::move(prog));
    }

-    DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-            {{
-                     DescriptorType::UNIFORM_BUFFER,
-                     ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                     DescriptorFlags::NONE, 0
-             }}});
-
-    DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);
-
    // Create a VertexBuffer, IndexBuffer, and RenderPrimitive.
    TrianglePrimitive const triangle(api);

@@ -402,7 +388,6 @@ TEST_F(BackendTest, ColorResolve) {

    PipelineState state = {};
    state.program = program;
-    state.pipelineLayout.setLayout[1] = { descriptorSetLayout };
    state.rasterState.colorWrite = true;
    state.rasterState.depthWrite = false;
    state.rasterState.depthFunc = RasterState::DepthFunc::A;
@@ -416,12 +401,10 @@ TEST_F(BackendTest, ColorResolve) {
        .scale = float4(1, 1, 0.5, 0),
    });

-    api.updateDescriptorSetBuffer(descriptorSet, 0, ubuffer, 0, sizeof(MaterialParams));
-    api.bindDescriptorSet(descriptorSet, 1, {});
-
    // FIXME: on Metal this triangle is not drawn. Can't understand why.
    api.beginFrame(0, 0, 0);
        api.beginRenderPass(srcRenderTarget, params);
+            api.bindUniformBuffer(0, ubuffer);
            api.draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
        api.endRenderPass();
    api.endFrame(0);
@@ -445,8 +428,6 @@ TEST_F(BackendTest, ColorResolve) {
    EXPECT_TRUE(sparams.pixelHashResult == expected);

    // Cleanup.
-    api.destroyDescriptorSet(descriptorSet);
-    api.destroyDescriptorSetLayout(descriptorSetLayout);
    api.destroyBufferObject(ubuffer);
    api.destroyProgram(program);
    api.destroyTexture(srcColorTexture);
--- a/filament/backend/test/test_BufferUpdates.cpp
+++ b/filament/backend/test/test_BufferUpdates.cpp
@@ -31,7 +31,7 @@ layout(location = 0) in vec4 mesh_position;

 layout(location = 0) out uvec4 indices;

-layout(binding = 0, set = 1) uniform Params {
+uniform Params {
    highp vec4 padding[4];  // offset of 64 bytes

    highp vec4 color;
@@ -51,7 +51,7 @@ std::string fragment (R"(#version 450 core

 layout(location = 0) out vec4 fragColor;

-layout(binding = 0, set = 1) uniform Params {
+uniform Params {
    highp vec4 padding[4];  // offset of 64 bytes

    highp vec4 color;
@@ -89,36 +89,20 @@ TEST_F(BackendTest, VertexBufferUpdate) {
    // The test is executed within this block scope to force destructors to run before
    // executeCommands().
    {
-        auto& api = getDriverApi();
-
        // Create a platform-specific SwapChain and make it current.
        auto swapChain = createSwapChain();
-        api.makeCurrent(swapChain, swapChain);
+        getDriverApi().makeCurrent(swapChain, swapChain);

        // Create a program.
-        filamat::DescriptorSets descriptors;
-        descriptors[1] = { { "Params",
-                { DescriptorType::UNIFORM_BUFFER, ShaderStageFlags::FRAGMENT, 0 }, {} } };
-        ShaderGenerator shaderGen(
-                vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
-        Program p = shaderGen.getProgram(api);
-        p.descriptorBindings(1, {{ "Params", DescriptorType::UNIFORM_BUFFER, 0 }});
-        auto program = api.createProgram(std::move(p));
+        ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform);
+        Program p = shaderGen.getProgram(getDriverApi());
+        auto program = getDriverApi().createProgram(std::move(p));

-        DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-                {{
-                         DescriptorType::UNIFORM_BUFFER,
-                         ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                         DescriptorFlags::NONE, 0
-                 }}});
-
-        DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);
-
-        auto defaultRenderTarget = api.createDefaultRenderTarget(0);
+        auto defaultRenderTarget = getDriverApi().createDefaultRenderTarget(0);

        // To test large buffers (which exercise a different code path) create an extra large
        // buffer. Only the first 3 vertices will be used.
-        TrianglePrimitive triangle(api, largeBuffers);
+        TrianglePrimitive triangle(getDriverApi(), largeBuffers);

        RenderPassParams params = {};
        fullViewport(params);
@@ -129,7 +113,6 @@ TEST_F(BackendTest, VertexBufferUpdate) {

        PipelineState state;
        state.program = program;
-        state.pipelineLayout.setLayout[1] = { descriptorSetLayout };
        state.rasterState.colorWrite = true;
        state.rasterState.depthWrite = false;
        state.rasterState.depthFunc = RasterState::DepthFunc::A;
@@ -138,13 +121,11 @@ TEST_F(BackendTest, VertexBufferUpdate) {
        // Create a uniform buffer.
        // We use STATIC here, even though the buffer is updated, to force the Metal backend to use a
        // GPU buffer, which is more interesting to test.
-        auto ubuffer = api.createBufferObject(sizeof(MaterialParams) + 64,
+        auto ubuffer = getDriverApi().createBufferObject(sizeof(MaterialParams) + 64,
                BufferObjectBinding::UNIFORM, BufferUsage::STATIC);
+        getDriverApi().bindUniformBuffer(0, ubuffer);

-        api.updateDescriptorSetBuffer(descriptorSet, 0, ubuffer, 0, sizeof(MaterialParams) + 64);
-        api.bindDescriptorSet(descriptorSet, 1, {});
-
-        api.startCapture(0);
+        getDriverApi().startCapture(0);

        // Upload uniforms.
        {
@@ -158,11 +139,11 @@ TEST_F(BackendTest, VertexBufferUpdate) {
                delete sp;
            };
            BufferDescriptor bd(tmp, sizeof(MaterialParams), cb);
-            api.updateBufferObject(ubuffer, std::move(bd), 64);
+            getDriverApi().updateBufferObject(ubuffer, std::move(bd), 64);
        }

-        api.makeCurrent(swapChain, swapChain);
-        api.beginFrame(0, 0, 0);
+        getDriverApi().makeCurrent(swapChain, swapChain);
+        getDriverApi().beginFrame(0, 0, 0);

        // Draw 10 triangles, updating the vertex buffer / index buffer each time.
        size_t triangleIndex = 0;
@@ -190,25 +171,22 @@ TEST_F(BackendTest, VertexBufferUpdate) {
                params.flags.discardStart = TargetBufferFlags::NONE;
            }

-            api.beginRenderPass(defaultRenderTarget, params);
-            api.draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
-            api.endRenderPass();
+            getDriverApi().beginRenderPass(defaultRenderTarget, params);
+            getDriverApi().draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
+            getDriverApi().endRenderPass();

            triangleIndex++;
        }

-        api.flush();
-        api.commit(swapChain);
-        api.endFrame(0);
+        getDriverApi().flush();
+        getDriverApi().commit(swapChain);
+        getDriverApi().endFrame(0);

-        api.stopCapture(0);
+        getDriverApi().stopCapture(0);

-        api.destroyProgram(program);
-        api.destroySwapChain(swapChain);
-        api.destroyDescriptorSet(descriptorSet);
-        api.destroyDescriptorSetLayout(descriptorSetLayout);
-        api.destroyBufferObject(ubuffer);
-        api.destroyRenderTarget(defaultRenderTarget);
+        getDriverApi().destroyProgram(program);
+        getDriverApi().destroySwapChain(swapChain);
+        getDriverApi().destroyRenderTarget(defaultRenderTarget);
    }

    executeCommands();
@@ -217,45 +195,27 @@ TEST_F(BackendTest, VertexBufferUpdate) {
 // This test renders two triangles in two separate draw calls. Between the draw calls, a uniform
 // buffer object is partially updated.
 TEST_F(BackendTest, BufferObjectUpdateWithOffset) {
-    auto& api = getDriverApi();
-
    // Create a platform-specific SwapChain and make it current.
    auto swapChain = createSwapChain();
-    api.makeCurrent(swapChain, swapChain);
+    getDriverApi().makeCurrent(swapChain, swapChain);

    // Create a program.
-    filamat::DescriptorSets descriptors;
-    descriptors[1] = { { "Params",
-            { DescriptorType::UNIFORM_BUFFER, ShaderStageFlags::FRAGMENT, 0 }, {} } };
-    ShaderGenerator shaderGen(
-            vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
-    Program p = shaderGen.getProgram(api);
-    p.descriptorBindings(1, {{ "Params", DescriptorType::UNIFORM_BUFFER, 0 }});
-    auto program = api.createProgram(std::move(p));
-
-    DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-            {{
-                     DescriptorType::UNIFORM_BUFFER,
-                     ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                     DescriptorFlags::NONE, 0
-             }}});
-
-    DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);
-
+    ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform);
+    Program p = shaderGen.getProgram(getDriverApi());
+    p.uniformBlockBindings({{"params", 1}});
+    auto program = getDriverApi().createProgram(std::move(p));

    // Create a uniform buffer.
    // We use STATIC here, even though the buffer is updated, to force the Metal backend to use a
    // GPU buffer, which is more interesting to test.
-    auto ubuffer = api.createBufferObject(sizeof(MaterialParams) + 64,
+    auto ubuffer = getDriverApi().createBufferObject(sizeof(MaterialParams) + 64,
            BufferObjectBinding::UNIFORM, BufferUsage::STATIC);
-
-    api.updateDescriptorSetBuffer(descriptorSet, 0, ubuffer, 0, sizeof(MaterialParams) + 64);
-    api.bindDescriptorSet(descriptorSet, 1, {});
+    getDriverApi().bindUniformBuffer(0, ubuffer);

    // Create a render target.
-    auto colorTexture = api.createTexture(SamplerType::SAMPLER_2D, 1,
+    auto colorTexture = getDriverApi().createTexture(SamplerType::SAMPLER_2D, 1,
            TextureFormat::RGBA8, 1, 512, 512, 1, TextureUsage::COLOR_ATTACHMENT);
-    auto renderTarget = api.createRenderTarget(
+    auto renderTarget = getDriverApi().createRenderTarget(
            TargetBufferFlags::COLOR0, 512, 512, 1, 0, {{colorTexture}}, {}, {});

    // Upload uniforms for the first triangle.
@@ -270,7 +230,7 @@ TEST_F(BackendTest, BufferObjectUpdateWithOffset) {
            delete sp;
        };
        BufferDescriptor bd(tmp, sizeof(MaterialParams), cb);
-        api.updateBufferObject(ubuffer, std::move(bd), 64);
+        getDriverApi().updateBufferObject(ubuffer, std::move(bd), 64);
    }

    RenderPassParams params = {};
@@ -280,8 +240,7 @@ TEST_F(BackendTest, BufferObjectUpdateWithOffset) {
    params.flags.discardEnd = TargetBufferFlags::NONE;
    params.viewport.height = 512;
    params.viewport.width = 512;
-    renderTriangle({{ DescriptorSetLayoutHandle{}, descriptorSetLayout }},
-            renderTarget, swapChain, program, params);
+    renderTriangle(renderTarget, swapChain, program, params);

    // Upload uniforms for the second triangle. To test partial buffer updates, we'll only update
    // color.b, color.a, offset.x, and offset.y.
@@ -296,32 +255,29 @@ TEST_F(BackendTest, BufferObjectUpdateWithOffset) {
            delete sp;
        };
        BufferDescriptor bd((char*)tmp + offsetof(MaterialParams, color.b), sizeof(float) * 4, cb);
-        api.updateBufferObject(ubuffer, std::move(bd), 64 + offsetof(MaterialParams, color.b));
+        getDriverApi().updateBufferObject(ubuffer, std::move(bd), 64 + offsetof(MaterialParams, color.b));
    }

    params.flags.clear = TargetBufferFlags::NONE;
    params.flags.discardStart = TargetBufferFlags::NONE;
-    renderTriangle({{ DescriptorSetLayoutHandle{}, descriptorSetLayout }},
-            renderTarget, swapChain, program, params);
+    renderTriangle(renderTarget, swapChain, program, params);

    static const uint32_t expectedHash = 91322442;
    readPixelsAndAssertHash(
            "BufferObjectUpdateWithOffset", 512, 512, renderTarget, expectedHash, true);

-    api.flush();
-    api.commit(swapChain);
-    api.endFrame(0);
+    getDriverApi().flush();
+    getDriverApi().commit(swapChain);
+    getDriverApi().endFrame(0);

-    api.destroyProgram(program);
-    api.destroySwapChain(swapChain);
-    api.destroyDescriptorSet(descriptorSet);
-    api.destroyDescriptorSetLayout(descriptorSetLayout);
-    api.destroyBufferObject(ubuffer);
-    api.destroyRenderTarget(renderTarget);
-    api.destroyTexture(colorTexture);
+    getDriverApi().destroyProgram(program);
+    getDriverApi().destroySwapChain(swapChain);
+    getDriverApi().destroyBufferObject(ubuffer);
+    getDriverApi().destroyRenderTarget(renderTarget);
+    getDriverApi().destroyTexture(colorTexture);

    // This ensures all driver commands have finished before exiting the test.
-    api.finish();
+    getDriverApi().finish();

    executeCommands();

--- a/filament/backend/test/test_ComputeBasic.cpp
+++ b/filament/backend/test/test_ComputeBasic.cpp
@@ -155,9 +155,8 @@ kernel void main0(device Output_data& output_data [[buffer(0)]],

    driver.dispatchCompute(ph, { groupCount, 1, 1 });

-// FIXME: we need a way to unbind the buffer in order to read from them
-//    driver.unbindBuffer(BufferObjectBinding::SHADER_STORAGE, 0);
-//    driver.unbindBuffer(BufferObjectBinding::SHADER_STORAGE, 1);
+    driver.unbindBuffer(BufferObjectBinding::SHADER_STORAGE, 0);
+    driver.unbindBuffer(BufferObjectBinding::SHADER_STORAGE, 1);

    float* const user = (float*)malloc(size);
    driver.readBufferSubData(output_data, 0, size, { user, size });
--- a/filament/backend/test/test_FeedbackLoops.cpp
+++ b/filament/backend/test/test_FeedbackLoops.cpp
@@ -19,17 +19,12 @@
 #include "ShaderGenerator.h"
 #include "TrianglePrimitive.h"

-#include <backend/DriverEnums.h>
-#include <backend/Handle.h>
+#include "private/backend/SamplerGroup.h"

 #include <utils/Hash.h>
 #include <utils/Log.h>

 #include <fstream>
-#include <string>
-
-#include <stddef.h>
-#include <stdint.h>

 #ifndef IOS
 #include <imageio/ImageEncoder.h>
@@ -42,28 +37,27 @@ using namespace image;
 // Shaders
 ////////////////////////////////////////////////////////////////////////////////////////////////////

-static std::string const fullscreenVs = R"(#version 450 core
+static std::string fullscreenVs = R"(#version 450 core
 layout(location = 0) in vec4 mesh_position;
 void main() {
    // Hack: move and scale triangle so that it covers entire viewport.
    gl_Position = vec4((mesh_position.xy + 0.5) * 5.0, 0.0, 1.0);
 })";

-static std::string const fullscreenFs = R"(#version 450 core
+static std::string fullscreenFs = R"(#version 450 core
 precision mediump int; precision highp float;
 layout(location = 0) out vec4 fragColor;

 // Filament's Vulkan backend requires a descriptor set index of 1 for all samplers.
 // This parameter is ignored for other backends.
-layout(binding = 0, set = 1) uniform sampler2D test_tex;
+layout(location = 0, set = 1) uniform sampler2D test_tex;

-layout(binding = 1, set = 1) uniform Params {
+uniform Params {
    highp float fbWidth;
    highp float fbHeight;
    highp float sourceLevel;
    highp float unused;
 } params;
-
 void main() {
    vec2 fbsize = vec2(params.fbWidth, params.fbHeight);
    vec2 uv = (gl_FragCoord.xy + 0.5) / fbsize;
@@ -112,12 +106,12 @@ static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> rt) {
        int w = kTexWidth, h = kTexHeight;
        const uint32_t* texels = (uint32_t*) buffer;
        sPixelHashResult = utils::hash::murmur3(texels, size / 4, 0);
-#ifndef IOS
+        #ifndef IOS
        LinearImage image(w, h, 4);
        image = toLinearWithAlpha<uint8_t>(w, h, w * 4, (uint8_t*) buffer);
        std::ofstream pngstrm("feedback.png", std::ios::binary | std::ios::trunc);
        ImageEncoder::encode(pngstrm, ImageEncoder::Format::PNG, image, "", "feedback.png");
-#endif
+        #endif
        free(buffer);
    };
    PixelBufferDescriptor pb(buffer, size, PixelDataFormat::RGBA, PixelDataType::UBYTE, cb);
@@ -140,37 +134,19 @@ TEST_F(BackendTest, FeedbackLoops) {
        // Create a program.
        ProgramHandle program;
        {
-            filament::SamplerInterfaceBlock::SamplerInfo samplerInfo { "test", "tex", 0,
-                SamplerType::SAMPLER_2D, SamplerFormat::FLOAT, Precision::HIGH, false };
-            filamat::DescriptorSets descriptors;
-            descriptors[1] = {
-                { "test_tex", { DescriptorType::SAMPLER, ShaderStageFlags::FRAGMENT, 0 },
-                        samplerInfo },
-                { "Params", { DescriptorType::UNIFORM_BUFFER, ShaderStageFlags::FRAGMENT, 1 }, {} }
-            };
-            ShaderGenerator shaderGen(fullscreenVs, fullscreenFs, sBackend, sIsMobilePlatform,
-                    std::move(descriptors));
+            SamplerInterfaceBlock const sib = filament::SamplerInterfaceBlock::Builder()
+                    .name("Test")
+                    .stageFlags(backend::ShaderStageFlags::ALL_SHADER_STAGE_FLAGS)
+                    .add( {{"tex", SamplerType::SAMPLER_2D, SamplerFormat::FLOAT, Precision::HIGH }} )
+                    .build();
+            ShaderGenerator shaderGen(fullscreenVs, fullscreenFs, sBackend, sIsMobilePlatform, &sib);
            Program prog = shaderGen.getProgram(api);
-            prog.descriptorBindings(1, {
-                    { "test_tex", DescriptorType::SAMPLER, 0 },
-                    { "Params", DescriptorType::UNIFORM_BUFFER, 1 }
-            });
+            Program::Sampler psamplers[] = { utils::CString("test_tex"), 0 };
+            prog.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, psamplers, sizeof(psamplers) / sizeof(psamplers[0]));
+            prog.uniformBlockBindings({{"params", 1}});
            program = api.createProgram(std::move(prog));
        }

-        DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-                {{
-                         DescriptorType::SAMPLER,
-                         ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                         DescriptorFlags::NONE, 0
-                 },
-                 {
-                         DescriptorType::UNIFORM_BUFFER,
-                         ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 1,
-                         DescriptorFlags::NONE, 0
-                 }}});
-
-
        TrianglePrimitive const triangle(getDriverApi());

        // Create a texture.
@@ -178,10 +154,6 @@ TEST_F(BackendTest, FeedbackLoops) {
        Handle<HwTexture> const texture = api.createTexture(
            SamplerType::SAMPLER_2D, kNumLevels, kTexFormat, 1, kTexWidth, kTexHeight, 1, usage);

-        // Create ubo
-        auto ubuffer = api.createBufferObject(sizeof(MaterialParams),
-                BufferObjectBinding::UNIFORM, BufferUsage::STATIC);
-
        // Create a RenderTarget for each miplevel.
        Handle<HwRenderTarget> renderTargets[kNumLevels];
        for (uint8_t level = 0; level < kNumLevels; level++) {
@@ -217,10 +189,20 @@ TEST_F(BackendTest, FeedbackLoops) {
            state.rasterState.depthWrite = false;
            state.rasterState.depthFunc = RasterState::DepthFunc::A;
            state.program = program;
-            state.pipelineLayout.setLayout[1] = { descriptorSetLayout };
-
+            SamplerGroup samplers(1);
+            SamplerParams sparams = {};
+            sparams.filterMag = SamplerMagFilter::LINEAR;
+            sparams.filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST;
+            samplers.setSampler(0, { texture, sparams });
+            auto sgroup =
+                    api.createSamplerGroup(samplers.getSize(), utils::FixedSizeString<32>("Test"));
+            api.updateSamplerGroup(sgroup, samplers.toBufferDescriptor(api));
+            auto ubuffer = api.createBufferObject(sizeof(MaterialParams),
+                    BufferObjectBinding::UNIFORM, BufferUsage::STATIC);
            api.makeCurrent(swapChain, swapChain);
            api.beginFrame(0, 0, 0);
+            api.bindSamplers(0, sgroup);
+            api.bindUniformBuffer(0, ubuffer);

            // Downsample passes
            params.flags.discardStart = TargetBufferFlags::ALL;
@@ -229,16 +211,7 @@ TEST_F(BackendTest, FeedbackLoops) {
                const uint32_t sourceLevel = targetLevel - 1;
                params.viewport.width = kTexWidth >> targetLevel;
                params.viewport.height = kTexHeight >> targetLevel;
-
-                auto textureView = api.createTextureView(texture, sourceLevel, 1);
-                DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);
-                api.updateDescriptorSetTexture(descriptorSet, 0, textureView, {
-                        .filterMag = SamplerMagFilter::LINEAR,
-                        .filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST
-                });
-                api.updateDescriptorSetBuffer(descriptorSet, 1, ubuffer, 0, sizeof(MaterialParams));
-                api.bindDescriptorSet(descriptorSet, 1, {});
-
+                getDriverApi().setMinMaxLevels(texture, sourceLevel, sourceLevel);
                uploadUniforms(getDriverApi(), ubuffer, {
                    .fbWidth = float(params.viewport.width),
                    .fbHeight = float(params.viewport.height),
@@ -247,8 +220,6 @@ TEST_F(BackendTest, FeedbackLoops) {
                api.beginRenderPass(renderTargets[targetLevel], params);
                api.draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
                api.endRenderPass();
-                api.destroyTexture(textureView);
-                api.destroyDescriptorSet(descriptorSet);
            }

            // Upsample passes
@@ -259,16 +230,7 @@ TEST_F(BackendTest, FeedbackLoops) {
                const uint32_t sourceLevel = targetLevel + 1;
                params.viewport.width = kTexWidth >> targetLevel;
                params.viewport.height = kTexHeight >> targetLevel;
-
-                auto textureView = api.createTextureView(texture, sourceLevel, 1);
-                DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);
-                api.updateDescriptorSetTexture(descriptorSet, 0, textureView, {
-                        .filterMag = SamplerMagFilter::LINEAR,
-                        .filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST
-                });
-                api.updateDescriptorSetBuffer(descriptorSet, 1, ubuffer, 0, sizeof(MaterialParams));
-                api.bindDescriptorSet(descriptorSet, 1, {});
-
+                getDriverApi().setMinMaxLevels(texture, sourceLevel, sourceLevel);
                uploadUniforms(getDriverApi(), ubuffer, {
                    .fbWidth = float(params.viewport.width),
                    .fbHeight = float(params.viewport.height),
@@ -277,10 +239,10 @@ TEST_F(BackendTest, FeedbackLoops) {
                api.beginRenderPass(renderTargets[targetLevel], params);
                api.draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
                api.endRenderPass();
-                api.destroyTexture(textureView);
-                api.destroyDescriptorSet(descriptorSet);
            }

+            getDriverApi().setMinMaxLevels(texture, 0, 0x7f);
+
            // Read back the render target corresponding to the base level.
            //
            // NOTE: Calling glReadPixels on any miplevel other than the base level
@@ -297,14 +259,10 @@ TEST_F(BackendTest, FeedbackLoops) {
            getDriver().purge();
        }

-        api.destroyDescriptorSetLayout(descriptorSetLayout);
        api.destroyProgram(program);
        api.destroySwapChain(swapChain);
        api.destroyTexture(texture);
-        api.destroyBufferObject(ubuffer);
-        for (auto rt : renderTargets)  {
-            api.destroyRenderTarget(rt);
-        }
+        for (auto rt : renderTargets)  api.destroyRenderTarget(rt);
    }

    const uint32_t expected = 0x70695aa1;
--- a/filament/backend/test/test_LoadImage.cpp
+++ b/filament/backend/test/test_LoadImage.cpp
@@ -20,18 +20,14 @@
 #include "TrianglePrimitive.h"
 #include "BackendTestUtils.h"

-#include <backend/DriverEnums.h>
-#include <backend/Handle.h>
-
 #include "private/filament/SamplerInterfaceBlock.h"
+#include "private/backend/SamplerGroup.h"

 #include <math/half.h>

+#include <fstream>
 #include <vector>

-#include <stddef.h>
-#include <stdint.h>
-
 using namespace filament;
 using namespace filament::backend;

@@ -301,31 +297,20 @@ TEST_F(BackendTest, UpdateImage2D) {
        auto defaultRenderTarget = api.createDefaultRenderTarget(0);

        // Create a program.
-        filament::SamplerInterfaceBlock::SamplerInfo samplerInfo { "test", "tex", 0,
-            SamplerType::SAMPLER_2D, getSamplerFormat(t.textureFormat), Precision::HIGH, false };
-        filamat::DescriptorSets descriptors;
-        descriptors[1] = { { "test_tex", { DescriptorType::SAMPLER, ShaderStageFlags::FRAGMENT, 0 },
-                samplerInfo } };
+        SamplerInterfaceBlock const sib = filament::SamplerInterfaceBlock::Builder()
+                .name("Test")
+                .stageFlags(backend::ShaderStageFlags::ALL_SHADER_STAGE_FLAGS)
+                .add( {{"tex", SamplerType::SAMPLER_2D, getSamplerFormat(t.textureFormat), Precision::HIGH }} )
+                .build();

        std::string const fragment = stringReplace("{samplerType}",
                getSamplerTypeName(t.textureFormat), fragmentTemplate);
-        ShaderGenerator shaderGen(
-                vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
-
+        ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform, &sib);
        Program prog = shaderGen.getProgram(api);
-        prog.descriptorBindings(1, {{"test_tex", DescriptorType::SAMPLER, 0}});
-
+        Program::Sampler psamplers[] = { utils::CString("test_tex"), 0 };
+        prog.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, psamplers, sizeof(psamplers) / sizeof(psamplers[0]));
        ProgramHandle const program = api.createProgram(std::move(prog));

-        DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-                {{
-                         DescriptorType::SAMPLER,
-                         ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                         DescriptorFlags::NONE, 0
-                 }}});
-
-        DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);
-
        // Create a Texture.
        auto usage = TextureUsage::SAMPLEABLE | TextureUsage::UPLOADABLE;
        Handle<HwTexture> const texture = api.createTexture(SamplerType::SAMPLER_2D, 1,
@@ -346,22 +331,23 @@ TEST_F(BackendTest, UpdateImage2D) {
                    checkerboardPixelBuffer(t.pixelFormat, t.pixelType, 512, t.bufferPadding));
        }

-        api.updateDescriptorSetTexture(descriptorSet, 0, texture, {
+        SamplerGroup samplers(1);
+        samplers.setSampler(0, { texture, {
                .filterMag = SamplerMagFilter::NEAREST,
-                .filterMin = SamplerMinFilter::NEAREST_MIPMAP_NEAREST });
+                .filterMin = SamplerMinFilter::NEAREST_MIPMAP_NEAREST } });

-        api.bindDescriptorSet(descriptorSet, 1, {});
+        auto sgroup = api.createSamplerGroup(samplers.getSize(), utils::FixedSizeString<32>("Test"));
+        api.updateSamplerGroup(sgroup, samplers.toBufferDescriptor(api));

-        renderTriangle({{ DescriptorSetLayoutHandle{}, descriptorSetLayout }},
-                defaultRenderTarget, swapChain, program);
+        api.bindSamplers(0, sgroup);
+
+        renderTriangle(defaultRenderTarget, swapChain, program);

        readPixelsAndAssertHash(t.name, 512, 512, defaultRenderTarget, expectedHash);

        api.commit(swapChain);
        api.endFrame(0);

-        api.destroyDescriptorSet(descriptorSet);
-        api.destroyDescriptorSetLayout(descriptorSetLayout);
        api.destroyProgram(program);
        api.destroySwapChain(swapChain);
        api.destroyRenderTarget(defaultRenderTarget);
@@ -388,27 +374,18 @@ TEST_F(BackendTest, UpdateImageSRGB) {
    auto defaultRenderTarget = api.createDefaultRenderTarget(0);

    // Create a program.
-    filament::SamplerInterfaceBlock::SamplerInfo samplerInfo { "test", "tex", 0,
-        SamplerType::SAMPLER_2D, getSamplerFormat(textureFormat), Precision::HIGH, false };
-    filamat::DescriptorSets descriptors;
-    descriptors[1] = { { "test_tex", { DescriptorType::SAMPLER, ShaderStageFlags::FRAGMENT, 0 },
-            samplerInfo } };
-
+    SamplerInterfaceBlock const sib = filament::SamplerInterfaceBlock::Builder()
+            .name("Test")
+            .stageFlags(backend::ShaderStageFlags::ALL_SHADER_STAGE_FLAGS)
+            .add( {{"tex", SamplerType::SAMPLER_2D, SamplerFormat::FLOAT, Precision::HIGH }} )
+            .build();
    std::string const fragment = stringReplace("{samplerType}",
            getSamplerTypeName(textureFormat), fragmentTemplate);
-    ShaderGenerator shaderGen(
-            vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
+    ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform, &sib);
    Program prog = shaderGen.getProgram(api);
-    prog.descriptorBindings(1, {{"test_tex", DescriptorType::SAMPLER, 0}});
+    Program::Sampler psamplers[] = { utils::CString("test_tex"), 0 };
+    prog.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, psamplers, sizeof(psamplers) / sizeof(psamplers[0]));
    ProgramHandle const program = api.createProgram(std::move(prog));
-    DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-            {{
-                     DescriptorType::SAMPLER,
-                     ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                     DescriptorFlags::NONE, 0
-             }}});
-
-    DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);

    // Create a texture.
    Handle<HwTexture> const texture = api.createTexture(SamplerType::SAMPLER_2D, 1,
@@ -440,15 +417,17 @@ TEST_F(BackendTest, UpdateImageSRGB) {
    api.beginFrame(0, 0, 0);

    // Update samplers.
-    api.updateDescriptorSetTexture(descriptorSet, 0, texture, {
-            .filterMag = SamplerMagFilter::LINEAR,
-            .filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST
-    });
+    SamplerGroup samplers(1);
+    SamplerParams sparams = {};
+    sparams.filterMag = SamplerMagFilter::LINEAR;
+    sparams.filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST;
+    samplers.setSampler(0, { texture, sparams });
+    auto sgroup = api.createSamplerGroup(samplers.getSize(), utils::FixedSizeString<32>("Test"));
+    api.updateSamplerGroup(sgroup, samplers.toBufferDescriptor(api));

-    api.bindDescriptorSet(descriptorSet, 1, {});
+    api.bindSamplers(0, sgroup);

-    renderTriangle({{ DescriptorSetLayoutHandle{}, descriptorSetLayout }},
-            defaultRenderTarget, swapChain, program);
+    renderTriangle(defaultRenderTarget, swapChain, program);

    static const uint32_t expectedHash = 359858623;
    readPixelsAndAssertHash("UpdateImageSRGB", 512, 512, defaultRenderTarget, expectedHash);
@@ -457,8 +436,7 @@ TEST_F(BackendTest, UpdateImageSRGB) {
    api.commit(swapChain);
    api.endFrame(0);

-    api.destroyDescriptorSet(descriptorSet);
-    api.destroyDescriptorSetLayout(descriptorSetLayout);
+    api.destroySamplerGroup(sgroup);
    api.destroyProgram(program);
    api.destroySwapChain(swapChain);
    api.destroyRenderTarget(defaultRenderTarget);
@@ -484,26 +462,18 @@ TEST_F(BackendTest, UpdateImageMipLevel) {
    auto defaultRenderTarget = api.createDefaultRenderTarget(0);

    // Create a program.
-    filament::SamplerInterfaceBlock::SamplerInfo samplerInfo { "test", "tex", 0,
-        SamplerType::SAMPLER_2D, getSamplerFormat(textureFormat), Precision::HIGH, false };
-    filamat::DescriptorSets descriptors;
-    descriptors[1] = { { "test_tex", { DescriptorType::SAMPLER, ShaderStageFlags::FRAGMENT, 0 },
-            samplerInfo } };
+    SamplerInterfaceBlock sib = filament::SamplerInterfaceBlock::Builder()
+            .name("Test")
+            .stageFlags(backend::ShaderStageFlags::ALL_SHADER_STAGE_FLAGS)
+            .add( {{"tex", SamplerType::SAMPLER_2D, SamplerFormat::FLOAT, Precision::HIGH }} )
+            .build();
    std::string const fragment = stringReplace("{samplerType}",
            getSamplerTypeName(textureFormat), fragmentUpdateImageMip);
-    ShaderGenerator shaderGen(
-            vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
+    ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform, &sib);
    Program prog = shaderGen.getProgram(api);
-    prog.descriptorBindings(1, {{"test_tex", DescriptorType::SAMPLER, 0}});
+    Program::Sampler psamplers[] = { utils::CString("test_tex"), 0 };
+    prog.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, psamplers, sizeof(psamplers) / sizeof(psamplers[0]));
    ProgramHandle const program = api.createProgram(std::move(prog));
-    DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-            {{
-                     DescriptorType::SAMPLER,
-                     ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                     DescriptorFlags::NONE, 0
-             }}});
-
-    DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);

    // Create a texture with 3 mip levels.
    // Base level: 1024
@@ -519,15 +489,17 @@ TEST_F(BackendTest, UpdateImageMipLevel) {
    api.beginFrame(0, 0, 0);

    // Update samplers.
-    api.updateDescriptorSetTexture(descriptorSet, 0, texture, {
-            .filterMag = SamplerMagFilter::LINEAR,
-            .filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST
-    });
+    SamplerGroup samplers(1);
+    SamplerParams sparams = {};
+    sparams.filterMag = SamplerMagFilter::LINEAR;
+    sparams.filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST;
+    samplers.setSampler(0, { texture, sparams });
+    auto sgroup = api.createSamplerGroup(samplers.getSize(), utils::FixedSizeString<32>("Test"));
+    api.updateSamplerGroup(sgroup, samplers.toBufferDescriptor(api));

-    api.bindDescriptorSet(descriptorSet, 1, {});
+    api.bindSamplers(0, sgroup);

-    renderTriangle({{ DescriptorSetLayoutHandle{}, descriptorSetLayout }},
-            defaultRenderTarget, swapChain, program);
+    renderTriangle(defaultRenderTarget, swapChain, program);

    static const uint32_t expectedHash = 3644679986;
    readPixelsAndAssertHash("UpdateImageMipLevel", 512, 512, defaultRenderTarget, expectedHash);
@@ -536,8 +508,7 @@ TEST_F(BackendTest, UpdateImageMipLevel) {
    api.commit(swapChain);
    api.endFrame(0);

-    api.destroyDescriptorSet(descriptorSet);
-    api.destroyDescriptorSetLayout(descriptorSetLayout);
+    api.destroySamplerGroup(sgroup);
    api.destroyProgram(program);
    api.destroySwapChain(swapChain);
    api.destroyRenderTarget(defaultRenderTarget);
@@ -565,26 +536,18 @@ TEST_F(BackendTest, UpdateImage3D) {
    auto defaultRenderTarget = api.createDefaultRenderTarget(0);

    // Create a program.
-    filament::SamplerInterfaceBlock::SamplerInfo samplerInfo { "test", "tex", 0,
-        SamplerType::SAMPLER_2D_ARRAY, getSamplerFormat(textureFormat), Precision::HIGH, false };
-    filamat::DescriptorSets descriptors;
-    descriptors[1] = { { "test_tex", { DescriptorType::SAMPLER, ShaderStageFlags::FRAGMENT, 0 },
-            samplerInfo } };
+    SamplerInterfaceBlock sib = filament::SamplerInterfaceBlock::Builder()
+            .name("Test")
+            .stageFlags(backend::ShaderStageFlags::ALL_SHADER_STAGE_FLAGS)
+            .add( {{"tex", SamplerType::SAMPLER_2D_ARRAY, SamplerFormat::FLOAT, Precision::HIGH }} )
+            .build();
    std::string fragment = stringReplace("{samplerType}",
            getSamplerTypeName(samplerType), fragmentUpdateImage3DTemplate);
-    ShaderGenerator shaderGen(
-            vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
+    ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform, &sib);
    Program prog = shaderGen.getProgram(api);
-    prog.descriptorBindings(1, {{ "test_tex", DescriptorType::SAMPLER, 0 }});
+    Program::Sampler psamplers[] = { utils::CString("test_tex"), 0 };
+    prog.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, psamplers, sizeof(psamplers) / sizeof(psamplers[0]));
    ProgramHandle const program = api.createProgram(std::move(prog));
-    DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-            {{
-                     DescriptorType::SAMPLER,
-                     ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                     DescriptorFlags::NONE, 0
-             }}});
-
-    DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);

    // Create a texture.
    Handle<HwTexture> texture = api.createTexture(samplerType, 1,
@@ -610,15 +573,17 @@ TEST_F(BackendTest, UpdateImage3D) {
    api.beginFrame(0, 0, 0);

    // Update samplers.
-    api.updateDescriptorSetTexture(descriptorSet, 0, texture, {
-            .filterMag = SamplerMagFilter::LINEAR,
-            .filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST
-    });
+    SamplerGroup samplers(1);
+    SamplerParams sparams = {};
+    sparams.filterMag = SamplerMagFilter::LINEAR;
+    sparams.filterMin = SamplerMinFilter::LINEAR_MIPMAP_NEAREST;
+    samplers.setSampler(0, { texture, sparams});
+    auto sgroup = api.createSamplerGroup(samplers.getSize(), utils::FixedSizeString<32>("Test"));
+    api.updateSamplerGroup(sgroup, samplers.toBufferDescriptor(api));

-    api.bindDescriptorSet(descriptorSet, 1, {});
+    api.bindSamplers(0, sgroup);

-    renderTriangle({{ DescriptorSetLayoutHandle{}, descriptorSetLayout }},
-            defaultRenderTarget, swapChain, program);
+    renderTriangle(defaultRenderTarget, swapChain, program);

    static const uint32_t expectedHash = 3644679986;
    readPixelsAndAssertHash("UpdateImage3D", 512, 512, defaultRenderTarget, expectedHash);
@@ -627,8 +592,7 @@ TEST_F(BackendTest, UpdateImage3D) {
    api.commit(swapChain);
    api.endFrame(0);

-    api.destroyDescriptorSet(descriptorSet);
-    api.destroyDescriptorSetLayout(descriptorSetLayout);
+    api.destroySamplerGroup(sgroup);
    api.destroyProgram(program);
    api.destroySwapChain(swapChain);
    api.destroyRenderTarget(defaultRenderTarget);
--- a/filament/backend/test/test_MipLevels.cpp
+++ b/filament/backend/test/test_MipLevels.cpp
@@ -21,11 +21,7 @@
 #include "TrianglePrimitive.h"
 #include "BackendTestUtils.h"

-#include <backend/DriverEnums.h>
-#include <backend/Handle.h>
-
-#include <stddef.h>
-#include <stdint.h>
+#include "private/backend/SamplerGroup.h"

 namespace {

@@ -75,7 +71,7 @@ namespace test {
 using namespace filament;
 using namespace filament::backend;

-TEST_F(BackendTest, TextureViewLod) {
+TEST_F(BackendTest, SetMinMaxLevel) {
    auto& api = getDriverApi();
    api.startCapture(0);

@@ -91,35 +87,26 @@ TEST_F(BackendTest, TextureViewLod) {
        {
            ShaderGenerator shaderGen(vertex, whiteFragment, sBackend, sIsMobilePlatform);
            Program p = shaderGen.getProgram(api);
-            p.descriptorBindings(0, {{"backend_test_sib_tex", DescriptorType::SAMPLER, 0}});
+            Program::Sampler sampler{utils::CString("backend_test_sib_tex"), 0};
+            p.setSamplerGroup(0, ShaderStageFlags::FRAGMENT, &sampler, 1);
            whiteProgram = api.createProgram(std::move(p));
        }

        // Create a program that samples a texture.
        Handle<HwProgram> textureProgram;
        {
-            filament::SamplerInterfaceBlock::SamplerInfo samplerInfo { "backend_test", "sib_tex", 0,
-                SamplerType::SAMPLER_2D, SamplerFormat::FLOAT, Precision::HIGH, false };
-            filamat::DescriptorSets descriptors;
-            descriptors[1] = { { "backend_test_sib_tex",
-                    { DescriptorType::SAMPLER, ShaderStageFlags::FRAGMENT, 0 }, samplerInfo } };
-            ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
+            SamplerInterfaceBlock sib = filament::SamplerInterfaceBlock::Builder()
+                    .name("backend_test_sib")
+                    .stageFlags(backend::ShaderStageFlags::FRAGMENT)
+                    .add( {{"tex", SamplerType::SAMPLER_2D, SamplerFormat::FLOAT, Precision::HIGH }} )
+                    .build();
+            ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform, &sib);
            Program p = shaderGen.getProgram(api);
-            p.descriptorBindings(0, {{"backend_test_sib_tex", DescriptorType::SAMPLER, 0}});
+            Program::Sampler sampler{utils::CString("backend_test_sib_tex"), 0};
+            p.setSamplerGroup(0, ShaderStageFlags::FRAGMENT, &sampler, 1);
            textureProgram = api.createProgram(std::move(p));
        }

-        DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-                {{
-                         DescriptorType::SAMPLER,
-                         ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                         DescriptorFlags::NONE, 0
-                 }}});
-
-        DescriptorSetHandle descriptorSet[2];
-        descriptorSet[0] = api.createDescriptorSet(descriptorSetLayout);
-        descriptorSet[1] = api.createDescriptorSet(descriptorSetLayout);
-
        // Create a texture that has 4 mip levels. Each level is a different color.
        // Level 0: 128x128 (red)
        // Level 1:   64x64 (green)
@@ -163,7 +150,7 @@ TEST_F(BackendTest, TextureViewLod) {
        // Level 1:   64x64 (green)             <-- base
        // Level 2:   32x32 (blue)              <--- white triangle rendered
        // Level 3:   16x16 (yellow)            <-- max
-        auto texture13 = api.createTextureView(texture, 1, 3);
+        api.setMinMaxLevels(texture, 1, 3);

        // Render a white triangle into level 2.
        // We specify mip level 2, because minMaxLevels has no effect when rendering into a texture.
@@ -196,17 +183,20 @@ TEST_F(BackendTest, TextureViewLod) {

        PipelineState state;
        state.program = textureProgram;
-        state.pipelineLayout.setLayout = { descriptorSetLayout };
        state.rasterState.colorWrite = true;
        state.rasterState.depthWrite = false;
        state.rasterState.depthFunc = SamplerCompareFunc::A;
        state.rasterState.culling = CullingMode::NONE;

-        api.updateDescriptorSetTexture(descriptorSet[0], 0, texture13, {
-                .filterMag = SamplerMagFilter::NEAREST,
-                .filterMin = SamplerMinFilter::NEAREST_MIPMAP_NEAREST });
-
-        api.bindDescriptorSet(descriptorSet[0], 0, {});
+        SamplerGroup samplers(1);
+        SamplerParams samplerParams {};
+        samplerParams.filterMag = SamplerMagFilter::NEAREST;
+        samplerParams.filterMin = SamplerMinFilter::NEAREST_MIPMAP_NEAREST;
+        samplers.setSampler(0, { texture, samplerParams });
+        backend::Handle<HwSamplerGroup> samplerGroup =
+                api.createSamplerGroup(1, utils::FixedSizeString<32>("Test"));
+        api.updateSamplerGroup(samplerGroup, samplers.toBufferDescriptor(api));
+        api.bindSamplers(0, samplerGroup);

        // Render a triangle to the screen, sampling from mip level 1.
        // Because the min level is 1, the result color should be the white triangle drawn in the
@@ -218,13 +208,7 @@ TEST_F(BackendTest, TextureViewLod) {

        // Adjust the base mip to 2.
        // Note that this is done without another call to updateSamplerGroup.
-        auto texture22 = api.createTextureView(texture, 2, 2);
-
-        api.updateDescriptorSetTexture(descriptorSet[1], 0, texture22, {
-                .filterMag = SamplerMagFilter::NEAREST,
-                .filterMin = SamplerMinFilter::NEAREST_MIPMAP_NEAREST });
-
-        api.bindDescriptorSet(descriptorSet[1], 0, {});
+        api.setMinMaxLevels(texture, 2, 3);

        // Render a second, smaller, triangle, again sampling from mip level 1.
        // This triangle should be yellow striped.
@@ -249,12 +233,7 @@ TEST_F(BackendTest, TextureViewLod) {
        // Cleanup.
        api.destroySwapChain(swapChain);
        api.destroyRenderTarget(renderTarget);
-        api.destroyDescriptorSet(descriptorSet[0]);
-        api.destroyDescriptorSet(descriptorSet[1]);
-        api.destroyDescriptorSetLayout(descriptorSetLayout);
        api.destroyTexture(texture);
-        api.destroyTexture(texture13);
-        api.destroyTexture(texture22);
        api.destroyProgram(whiteProgram);
        api.destroyProgram(textureProgram);
    }
--- a/filament/backend/test/test_RenderExternalImage.cpp
+++ b/filament/backend/test/test_RenderExternalImage.cpp
@@ -19,14 +19,10 @@
 #include "ShaderGenerator.h"
 #include "TrianglePrimitive.h"

-#include <backend/DriverEnums.h>
-#include <backend/Handle.h>
+#include "private/backend/SamplerGroup.h"

 #include <CoreVideo/CoreVideo.h>

-#include <stddef.h>
-#include <stdint.h>
-
 namespace {

 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -65,39 +61,29 @@ using namespace filament::backend;

 // Rendering an external image without setting any data should not crash.
 TEST_F(BackendTest, RenderExternalImageWithoutSet) {
-    auto& api = getDriverApi();
-
-    TrianglePrimitive triangle(api);
+    TrianglePrimitive triangle(getDriverApi());

    auto swapChain = createSwapChain();

-    filament::SamplerInterfaceBlock::SamplerInfo samplerInfo { "test", "tex", 0,
-        SamplerType::SAMPLER_EXTERNAL, SamplerFormat::FLOAT, Precision::HIGH, false };
-    filamat::DescriptorSets descriptors;
-    descriptors[1] = { { "test_tex", { DescriptorType::SAMPLER, ShaderStageFlags::FRAGMENT, 0 },
-            samplerInfo } };
-    ShaderGenerator shaderGen(
-            vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
+    SamplerInterfaceBlock sib = filament::SamplerInterfaceBlock::Builder()
+            .name("Test")
+            .stageFlags(backend::ShaderStageFlags::ALL_SHADER_STAGE_FLAGS)
+            .add( {{"tex", SamplerType::SAMPLER_EXTERNAL, SamplerFormat::FLOAT, Precision::HIGH }} )
+            .build();
+    ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform, &sib);

    // Create a program that samples a texture.
-    Program p = shaderGen.getProgram(api);
-    p.descriptorBindings(1, {{"test_tex", DescriptorType::SAMPLER, 0}});
-    backend::Handle<HwProgram> program = api.createProgram(std::move(p));
-    DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-            {{
-                     DescriptorType::SAMPLER,
-                     ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                     DescriptorFlags::NONE, 0
-             }}});
+    Program p = shaderGen.getProgram(getDriverApi());
+    Program::Sampler sampler { utils::CString("test_tex"), 0 };
+    p.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, &sampler, 1);
+    backend::Handle<HwProgram> program = getDriverApi().createProgram(std::move(p));

-    DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);
-
-    backend::Handle<HwRenderTarget> defaultRenderTarget = api.createDefaultRenderTarget(0);
+    backend::Handle<HwRenderTarget> defaultRenderTarget = getDriverApi().createDefaultRenderTarget(0);

    // Create a texture that will be backed by an external image.
    auto usage = TextureUsage::COLOR_ATTACHMENT | TextureUsage::SAMPLEABLE;
    const NativeView& view = getNativeView();
-    backend::Handle<HwTexture> texture = api.createTexture(
+    backend::Handle<HwTexture> texture = getDriverApi().createTexture(
                SamplerType::SAMPLER_EXTERNAL,      // target
                1,                                  // levels
                TextureFormat::RGBA8,               // format
@@ -116,74 +102,63 @@ TEST_F(BackendTest, RenderExternalImageWithoutSet) {

    PipelineState state;
    state.program = program;
-    state.pipelineLayout.setLayout[1] = { descriptorSetLayout };
    state.rasterState.colorWrite = true;
    state.rasterState.depthWrite = false;
    state.rasterState.depthFunc = RasterState::DepthFunc::A;
    state.rasterState.culling = CullingMode::NONE;

-    api.startCapture(0);
-    api.makeCurrent(swapChain, swapChain);
-    api.beginFrame(0, 0, 0);
+    getDriverApi().startCapture(0);
+    getDriverApi().makeCurrent(swapChain, swapChain);
+    getDriverApi().beginFrame(0, 0, 0);

-    api.updateDescriptorSetTexture(descriptorSet, 0, texture, {});
-    api.bindDescriptorSet(descriptorSet, 1, {});
+    SamplerGroup samplers(1);
+    samplers.setSampler(0, { texture, {} });
+    backend::Handle<HwSamplerGroup> samplerGroup =
+            getDriverApi().createSamplerGroup(1, utils::FixedSizeString<32>("Test"));
+    getDriverApi().updateSamplerGroup(samplerGroup, samplers.toBufferDescriptor(getDriverApi()));
+    getDriverApi().bindSamplers(0, samplerGroup);

    // Render a triangle.
-    api.beginRenderPass(defaultRenderTarget, params);
-    api.draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
-    api.endRenderPass();
+    getDriverApi().beginRenderPass(defaultRenderTarget, params);
+    getDriverApi().draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
+    getDriverApi().endRenderPass();

-    api.flush();
-    api.commit(swapChain);
-    api.endFrame(0);
+    getDriverApi().flush();
+    getDriverApi().commit(swapChain);
+    getDriverApi().endFrame(0);

-    api.stopCapture(0);
+    getDriverApi().stopCapture(0);

    // Delete our resources.
-    api.destroyDescriptorSet(descriptorSet);
-    api.destroyDescriptorSetLayout(descriptorSetLayout);
-    api.destroyTexture(texture);
+    getDriverApi().destroyTexture(texture);
+    getDriverApi().destroySamplerGroup(samplerGroup);

    // Destroy frame resources.
-    api.destroyProgram(program);
-    api.destroyRenderTarget(defaultRenderTarget);
-
-    api.finish();
+    getDriverApi().destroyProgram(program);
+    getDriverApi().destroyRenderTarget(defaultRenderTarget);

    executeCommands();
 }

 TEST_F(BackendTest, RenderExternalImage) {
-    auto& api = getDriverApi();
-
-    TrianglePrimitive triangle(api);
+    TrianglePrimitive triangle(getDriverApi());

    auto swapChain = createSwapChain();

-    filament::SamplerInterfaceBlock::SamplerInfo samplerInfo { "test", "tex", 0,
-        SamplerType::SAMPLER_EXTERNAL, SamplerFormat::FLOAT, Precision::HIGH, false };
-    filamat::DescriptorSets descriptors;
-    descriptors[1] = { { "test_tex", { DescriptorType::SAMPLER, ShaderStageFlags::FRAGMENT, 0 },
-            samplerInfo } };
-    ShaderGenerator shaderGen(
-            vertex, fragment, sBackend, sIsMobilePlatform, std::move(descriptors));
+    SamplerInterfaceBlock sib = filament::SamplerInterfaceBlock::Builder()
+            .name("Test")
+            .stageFlags(backend::ShaderStageFlags::ALL_SHADER_STAGE_FLAGS)
+            .add( {{"tex", SamplerType::SAMPLER_EXTERNAL, SamplerFormat::FLOAT, Precision::HIGH }} )
+            .build();
+    ShaderGenerator shaderGen(vertex, fragment, sBackend, sIsMobilePlatform, &sib);

    // Create a program that samples a texture.
-    Program p = shaderGen.getProgram(api);
-    p.descriptorBindings(1, {{"test_tex", DescriptorType::SAMPLER, 0}});
-    auto program = api.createProgram(std::move(p));
+    Program p = shaderGen.getProgram(getDriverApi());
+    Program::Sampler sampler { utils::CString("test_tex"), 0 };
+    p.setSamplerGroup(0, ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, &sampler, 1);
+    auto program = getDriverApi().createProgram(std::move(p));

-    DescriptorSetLayoutHandle descriptorSetLayout = api.createDescriptorSetLayout({
-            {{
-                     DescriptorType::SAMPLER,
-                     ShaderStageFlags::ALL_SHADER_STAGE_FLAGS, 0,
-                     DescriptorFlags::NONE, 0
-             }}});
-
-    DescriptorSetHandle descriptorSet = api.createDescriptorSet(descriptorSetLayout);
-
-    backend::Handle<HwRenderTarget> defaultRenderTarget = api.createDefaultRenderTarget(0);
+    backend::Handle<HwRenderTarget> defaultRenderTarget = getDriverApi().createDefaultRenderTarget(0);

    // require users to create two Filament textures and have two material parameters
    // add a "plane" parameter to setExternalImage
@@ -191,6 +166,15 @@ TEST_F(BackendTest, RenderExternalImage) {
    // Create a texture that will be backed by an external image.
    auto usage = TextureUsage::COLOR_ATTACHMENT | TextureUsage::SAMPLEABLE;
    const NativeView& view = getNativeView();
+    backend::Handle<HwTexture> texture = getDriverApi().createTexture(
+                SamplerType::SAMPLER_EXTERNAL,      // target
+                1,                                  // levels
+                TextureFormat::RGBA8,               // format
+                1,                                  // samples
+                view.width,                         // width
+                view.height,                        // height
+                1,                                  // depth
+                usage);                             // usage

    // Create an external image.
    CFStringRef keys[4];
@@ -225,9 +209,8 @@ TEST_F(BackendTest, RenderExternalImage) {
        }
    }

-    api.setupExternalImage(pixBuffer);
-    backend::Handle<HwTexture> texture =
-            api.createTextureExternalImage(TextureFormat::RGBA8, 1024, 1024, usage, pixBuffer);
+    getDriverApi().setupExternalImage(pixBuffer);
+    getDriverApi().setExternalImage(texture, pixBuffer);

    // We're now free to release the buffer.
    CVBufferRelease(pixBuffer);
@@ -241,43 +224,40 @@ TEST_F(BackendTest, RenderExternalImage) {

    PipelineState state;
    state.program = program;
-    state.pipelineLayout.setLayout[1] = { descriptorSetLayout };
    state.rasterState.colorWrite = true;
    state.rasterState.depthWrite = false;
    state.rasterState.depthFunc = RasterState::DepthFunc::A;
    state.rasterState.culling = CullingMode::NONE;

-    api.startCapture(0);
-    api.makeCurrent(swapChain, swapChain);
-    api.beginFrame(0, 0, 0);
+    getDriverApi().startCapture(0);
+    getDriverApi().makeCurrent(swapChain, swapChain);
+    getDriverApi().beginFrame(0, 0, 0);

-    api.updateDescriptorSetTexture(descriptorSet, 0, texture, {});
-
-    api.bindDescriptorSet(descriptorSet, 1, {});
+    SamplerGroup samplers(1);
+    samplers.setSampler(0, { texture, {} });
+    backend::Handle<HwSamplerGroup> samplerGroup =
+            getDriverApi().createSamplerGroup(1, utils::FixedSizeString<32>("Test"));
+    getDriverApi().updateSamplerGroup(samplerGroup, samplers.toBufferDescriptor(getDriverApi()));
+    getDriverApi().bindSamplers(0, samplerGroup);

    // Render a triangle.
-    api.beginRenderPass(defaultRenderTarget, params);
-    api.draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
-    api.endRenderPass();
+    getDriverApi().beginRenderPass(defaultRenderTarget, params);
+    getDriverApi().draw(state, triangle.getRenderPrimitive(), 0, 3, 1);
+    getDriverApi().endRenderPass();

-    readPixelsAndAssertHash("RenderExternalImage", 512, 512, defaultRenderTarget, 267229901, true);
+    getDriverApi().flush();
+    getDriverApi().commit(swapChain);
+    getDriverApi().endFrame(0);

-    api.flush();
-    api.commit(swapChain);
-    api.endFrame(0);
-
-    api.stopCapture(0);
+    getDriverApi().stopCapture(0);

    // Delete our resources.
-    api.destroyDescriptorSet(descriptorSet);
-    api.destroyDescriptorSetLayout(descriptorSetLayout);
-    api.destroyTexture(texture);
+    getDriverApi().destroyTexture(texture);
+    getDriverApi().destroySamplerGroup(samplerGroup);

    // Destroy frame resources.
-    api.destroyProgram(program);
-    api.destroyRenderTarget(defaultRenderTarget);
-
-    api.finish();
+    getDriverApi().destroyProgram(program);
+    getDriverApi().destroyRenderTarget(defaultRenderTarget);

    executeCommands();
 }
--- a/filament/docs/Vulkan.md.html
+++ b/filament/docs/Vulkan.md.html
@@ -182,7 +182,7 @@ updated several times; each time it undergoes these two transitions.

 If a shader samples from a texture whose mipmaps are only partially loaded, we might see validation
 warnings about how some subresources are in an UNDEFINED layout.  However if we are properly using
-the `createTextureView` driver API, then the Vulkan backend will not bind those particular
+the `setMinMaxLevels` driver API, then the Vulkan backend will not bind those particular
 subresources, so validation should not complain.

 (2) **Writeable Color Textures**
--- a/filament/include/filament/BufferObject.h
+++ b/filament/include/filament/BufferObject.h
@@ -54,7 +54,7 @@ public:
    using BufferDescriptor = backend::BufferDescriptor;
    using BindingType = backend::BufferObjectBinding;

-    class Builder : public BuilderBase<BuilderDetails>, public BuilderNameMixin<Builder> {
+    class Builder : public BuilderBase<BuilderDetails> {
        friend struct BuilderDetails;
    public:
        Builder() noexcept;
@@ -78,21 +78,6 @@ public:
         */
        Builder& bindingType(BindingType bindingType) noexcept;

-        /**
-         * Associate an optional name with this BufferObject for debugging purposes.
-         *
-         * name will show in error messages and should be kept as short as possible. The name is
-         * truncated to a maximum of 128 characters.
-         *
-         * The name string is copied during this method so clients may free its memory after
-         * the function returns.
-         *
-         * @param name A string to identify this BufferObject
-         * @param len Length of name, should be less than or equal to 128
-         * @return This Builder, for chaining calls.
-         */
-        // Builder& name(const char* UTILS_NONNULL name, size_t len) noexcept; // inherited
-
        /**
         * Creates the BufferObject and returns a pointer to it. After creation, the buffer
         * object is uninitialized. Use BufferObject::setBuffer() to initialize it.
--- a/filament/include/filament/Engine.h
+++ b/filament/include/filament/Engine.h
@@ -896,29 +896,6 @@ public:
    /** Tells whether an InstanceBuffer object is valid */
    bool isValid(const InstanceBuffer* UTILS_NULLABLE p) const;

-    /**
-     * Retrieve the count of each resource tracked by Engine.
-     * This is intended for debugging.
-     * @{
-     */
-    size_t getBufferObjectCount() const noexcept;
-    size_t getViewCount() const noexcept;
-    size_t getSceneCount() const noexcept;
-    size_t getSwapChainCount() const noexcept;
-    size_t getStreamCount() const noexcept;
-    size_t getIndexBufferCount() const noexcept;
-    size_t getSkinningBufferCount() const noexcept;
-    size_t getMorphTargetBufferCount() const noexcept;
-    size_t getInstanceBufferCount() const noexcept;
-    size_t getVertexBufferCount() const noexcept;
-    size_t getIndirectLightCount() const noexcept;
-    size_t getMaterialCount() const noexcept;
-    size_t getTextureCount() const noexcept;
-    size_t getSkyboxeCount() const noexcept;
-    size_t getColorGradingCount() const noexcept;
-    size_t getRenderTargetCount() const noexcept;
-    /**  @} */
-
    /**
     * Kicks the hardware thread (e.g. the OpenGL, Vulkan or Metal thread) and blocks until
     * all commands to this point are executed. Note that does guarantee that the
--- a/filament/include/filament/FilamentAPI.h
+++ b/filament/include/filament/FilamentAPI.h
@@ -19,7 +19,6 @@

 #include <utils/compiler.h>
 #include <utils/PrivateImplementation.h>
-#include <utils/CString.h>

 #include <stddef.h>

@@ -55,23 +54,6 @@ public:
 template<typename T>
 using BuilderBase = utils::PrivateImplementation<T>;

-// This needs to be public because it is used in the following template.
-UTILS_PUBLIC void builderMakeName(utils::CString& outName, const char* name, size_t len) noexcept;
-
-template <typename Builder>
-class UTILS_PUBLIC BuilderNameMixin {
-public:
-    Builder& name(const char* name, size_t len) noexcept {
-        builderMakeName(mName, name, len);
-        return static_cast<Builder&>(*this);
-    }
-
-    utils::CString const& getName() const noexcept { return mName; }
-
-private:
-    utils::CString mName;
-};
-
 } // namespace filament

 #endif // TNT_FILAMENT_FILAMENTAPI_H
--- a/filament/include/filament/IndexBuffer.h
+++ b/filament/include/filament/IndexBuffer.h
@@ -59,7 +59,7 @@ public:
        UINT = uint8_t(backend::ElementType::UINT),      //!< 32-bit indices
    };

-    class Builder : public BuilderBase<BuilderDetails>, public BuilderNameMixin<Builder> {
+    class Builder : public BuilderBase<BuilderDetails> {
        friend struct BuilderDetails;
    public:
        Builder() noexcept;
@@ -83,21 +83,6 @@ public:
         */
        Builder& bufferType(IndexType indexType) noexcept;

-        /**
-         * Associate an optional name with this IndexBuffer for debugging purposes.
-         *
-         * name will show in error messages and should be kept as short as possible. The name is
-         * truncated to a maximum of 128 characters.
-         *
-         * The name string is copied during this method so clients may free its memory after
-         * the function returns.
-         *
-         * @param name A string to identify this IndexBuffer
-         * @param len Length of name, should be less than or equal to 128
-         * @return This Builder, for chaining calls.
-         */
-        // Builder& name(const char* UTILS_NONNULL name, size_t len) noexcept; // inherited
-
        /**
         * Creates the IndexBuffer object and returns a pointer to it. After creation, the index
         * buffer is uninitialized. Use IndexBuffer::setBuffer() to initialize the IndexBuffer.
--- a/Show More
+++ b/Show More