Merge branch 'rc/1.21.1' into release

because a float->integer conversion is needed, it's better to let the
caller decide what they want.

.github/workflows/release.yml

@@ -50,8 +50,7 @@ jobs:
           cd build/$WORKFLOW_OS && printf "y" | ./build.sh release
       - name: Upload release assets
         run: |
-          pip3 install setuptools
-          pip3 install PyGithub
+          xargs -L 1 sudo pip3 install < build/common/requirements.txt
           if [ -f out/filament-release-darwin.tgz ]; then mv out/filament-release-darwin.tgz out/filament-${TAG}-mac.tgz; fi;
           if [ -f out/filament-release-linux.tgz ]; then mv out/filament-release-linux.tgz out/filament-${TAG}-linux.tgz; fi;
           python3 build/common/upload-assets.py ${TAG} out/*.tgz
@@ -80,8 +79,7 @@ jobs:
           cd build/web && printf "y" | ./build.sh release
       - name: Upload release assets
         run: |
-          pip3 install setuptools
-          pip3 install PyGithub
+          xargs -L 1 sudo pip3 install < build/common/requirements.txt
           mv out/filament-release-web.tgz out/filament-${TAG}-web.tgz
           python3 build/common/upload-assets.py ${TAG} out/*.tgz
         env:
@@ -123,15 +121,13 @@ jobs:
           APK_KEYSTORE_PASS: ${{ secrets.APK_KEYSTORE_PASS }}
       - name: Upload release assets
         run: |
-          pip3 install setuptools
-          pip3 install PyGithub
+          xargs -L 1 sudo pip3 install < build/common/requirements.txt
           mv out/filament-android-release.aar out/filament-${TAG}-android.aar
           mv out/filamat-android-release.aar out/filamat-${TAG}-android.aar
           mv out/filamat-android-lite-release.aar out/filamat-${TAG}-lite-android.aar
           mv out/gltfio-android-release.aar out/gltfio-${TAG}-android.aar
           mv out/gltfio-android-lite-release.aar out/gltfio-${TAG}-lite-android.aar
           mv out/filament-utils-android-release.aar out/filament-utils-${TAG}-android.aar
-          mv out/filament-utils-android-lite-release.aar out/filament-utils-${TAG}-lite-android.aar
           python3 build/common/upload-assets.py ${TAG} out/*.aar out/*.apk
         env:
           TAG: ${{ steps.git_ref.outputs.tag }}
@@ -158,8 +154,7 @@ jobs:
           cd build/ios && printf "y" | ./build.sh release
       - name: Upload release assets
         run: |
-          pip3 install setuptools
-          pip3 install PyGithub
+          xargs -L 1 sudo pip3 install < build/common/requirements.txt
           mv out/filament-release-ios.tgz out/filament-${TAG}-ios.tgz
           python3 build/common/upload-assets.py ${TAG} out/*.tgz
         env:

README.md

@@ -31,7 +31,7 @@ repositories {
 }
 
 dependencies {
-    implementation 'com.google.android.filament:filament-android:1.20.5'
+    implementation 'com.google.android.filament:filament-android:1.21.1'
 }
 ```
 
@@ -43,7 +43,6 @@ Here are all the libraries available in the group `com.google.android.filament`:
 | [![gltfio-android](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/gltfio-android/badge.svg?subject=gltfio-android)](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/gltfio-android) | A glTF 2.0 loader for Filament, depends on `filament-android`. |
 | [![gltfio-android-lite](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/gltfio-android-lite/badge.svg?subject=gltfio-android-lite)](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/gltfio-android-lite) | Trimmed version of `gltfio` that does not support some glTF extensions. |
 | [![filament-utils-android](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/filament-utils-android/badge.svg?subject=filament-utils-android)](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/filament-utils-android) | KTX loading, Kotlin math, and camera utilities, depends on `gltfio-android`. |
-| [![filament-utils-android-lite](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/filament-utils-android-lite/badge.svg?subject=filament-utils-lite)](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/filament-utils-android-lite) | Trimmed version of `filament-utils` that does not support some glTF features. |
 | [![filamat-android](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/filamat-android/badge.svg?subject=filamat-android)](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/filamat-android) | A runtime material builder/compiler. This library is large but contains a full shader compiler/validator/optimizer and supports both OpenGL and Vulkan. |
 | [![filamat-android-lite](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/filamat-android-lite/badge.svg?subject=filamat-android-lite)](https://maven-badges.herokuapp.com/maven-central/com.google.android.filament/filamat-android-lite) | A much smaller alternative to `filamat-android` that can only generate OpenGL shaders. It does not provide validation or optimizations. |
 
@@ -52,7 +51,7 @@ Here are all the libraries available in the group `com.google.android.filament`:
 iOS projects can use CocoaPods to install the latest release:
 
 ```
-pod 'Filament', '~> 1.20.5'
+pod 'Filament', '~> 1.21.1'
 ```
 
 ### Snapshots
@@ -169,11 +168,13 @@ steps:
   - [x] KHR_draco_mesh_compression
   - [x] KHR_lights_punctual
   - [x] KHR_materials_clearcoat
+  - [x] KHR_materials_emissive_strength
   - [x] KHR_materials_ior
   - [x] KHR_materials_pbrSpecularGlossiness
   - [x] KHR_materials_sheen
   - [x] KHR_materials_transmission
   - [x] KHR_materials_unlit
+  - [x] KHR_materials_variants
   - [x] KHR_materials_volume
   - [x] KHR_mesh_quantization
   - [x] KHR_texture_transform

RELEASE_NOTES.md

@@ -3,7 +3,24 @@
 This file contains one line summaries of commits that are worthy of mentioning in release notes.
 A new header is inserted each time a *tag* is created.
 
-## v1.20.6 (currently main branch)
+## v1.21.2 (currently main branch)
+
+## v1.21.1
+
+- engine: Allow both screen-space refraction and screen-space reflections on the same object [⚠️ **Material breakage**].
+- engine: Optimizations for screen-space reflections.
+- engine: Remove `Viewport::scale()` [⚠️ **API Change**].
+- engine: Fix 12x overallocation of memory in `MorphTargetBuffer`.
+- Metal: Fix validation error when reading from default `SwapChain`.
+
+## v1.21.0
+
+- engine: OpenGL performance improvements with some drivers.
+- engine: Fix incorrect shadows with some custom projection matrices.
+- engine: Fix low frame rates seen with a lot of morph targets.
+- gltfio: Add support for KHR_materials_variants.
+- gltfio: Add support for KHR_materials_emissive_strength.
+- gltfio: Java now exposes morph target names as an array for consistency [⚠️ **API Change**].
 
 ## v1.20.5
 

android/filament-utils-android/build.gradle

@@ -1,30 +1,16 @@
 apply plugin: 'kotlin-android'
 
 android {
-    flavorDimensions "functionality"
-    productFlavors {
-        full {
-            dimension "functionality"
-        }
-
-        lite {
-            dimension "functionality"
-            externalNativeBuild {
-                cmake {
-                    // hack: this is needed because filament-utils-android/CMakeLists.txt builds
-                    // gltfio from source, which needs this defined
-                    arguments.add("-DGLTFIO_LITE=ON")
-                }
-            }
-        }
-    }
-
     sourceSets {
         main {
             kotlin.srcDirs += "src/main/java"
         }
     }
 
+    defaultConfig {
+        missingDimensionStrategy 'functionality', 'full'
+    }
+
     // No need to package up the following shared libs, which arise as a side effect of our
     // externalNativeBuild dependencies. When clients pick and choose from project-level gradle
     // dependencies, these shared libs already get pulled in, so we need to avoid the error:
@@ -55,9 +41,7 @@ dependencies {
     implementation deps.coroutines.android
 
     api project(':filament-android')
-
-    fullApi module("com.google.android.filament:gltfio-android:${VERSION_NAME}")
-    liteApi module("com.google.android.filament:gltfio-android-lite:${VERSION_NAME}")
+    api module("com.google.android.filament:gltfio-android:${VERSION_NAME}")
 }
 
 apply from: rootProject.file('gradle/gradle-mvn-push.gradle')
@@ -65,14 +49,9 @@ apply from: rootProject.file('gradle/gradle-mvn-push.gradle')
 afterEvaluate {
     publishing {
         publications {
-            fullRelease(MavenPublication) {
-                artifactId = POM_ARTIFACT_ID_FULL
-                from components.fullRelease
-            }
-
-            liteRelease(MavenPublication) {
-                artifactId = POM_ARTIFACT_ID_LITE
-                from components.liteRelease
+            release(MavenPublication) {
+                artifactId = POM_ARTIFACT_ID
+                from components.release
             }
         }
     }

android/filament-utils-android/gradle.properties

@@ -1,4 +1,3 @@
 POM_NAME=Filament Android Utilities
-POM_ARTIFACT_ID_FULL=filament-utils-android
-POM_ARTIFACT_ID_LITE=filament-utils-android-lite
+POM_ARTIFACT_ID=filament-utils-android
 POM_PACKAGING=aar

android/gltfio-android/src/main/cpp/FilamentAsset.cpp

@@ -215,15 +215,6 @@ Java_com_google_android_filament_gltfio_FilamentAsset_nGetResourceUriCount(JNIEn
     return (jint) asset->getResourceUriCount();
 }
 
-extern "C" JNIEXPORT jstring JNICALL
-Java_com_google_android_filament_gltfio_FilamentAsset_nGetMorphTargetNameAt(JNIEnv* env, jclass,
-        jlong nativeAsset, jint entityId, jint targetIndex) {
-    Entity entity = Entity::import(entityId);
-    FilamentAsset* asset = (FilamentAsset*) nativeAsset;
-    const char* val = asset->getMorphTargetNameAt(entity, (size_t) targetIndex);
-    return val ? env->NewStringUTF(val) : nullptr;
-}
-
 extern "C" JNIEXPORT void JNICALL
 Java_com_google_android_filament_gltfio_FilamentAsset_nGetResourceUris(JNIEnv* env, jclass,
                                                                        jlong nativeAsset,
@@ -235,6 +226,49 @@ Java_com_google_android_filament_gltfio_FilamentAsset_nGetResourceUris(JNIEnv* e
     }
 }
 
+extern "C" JNIEXPORT jint JNICALL
+Java_com_google_android_filament_gltfio_FilamentAsset_nGetMorphTargetCount(JNIEnv*, jclass,
+        jlong nativeAsset, jint entityId) {
+    FilamentAsset* asset = (FilamentAsset*) nativeAsset;
+    Entity entity = Entity::import(entityId);
+    return (jint) asset->getMorphTargetCountAt(entity);
+}
+
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_gltfio_FilamentAsset_nGetMorphTargetNames(JNIEnv* env, jclass,
+        jlong nativeAsset, jint entityId, jobjectArray result) {
+    FilamentAsset* asset = (FilamentAsset*) nativeAsset;
+    Entity entity = Entity::import(entityId);
+    for (int i = 0, n = asset->getMorphTargetCountAt(entity); i < n; ++i) {
+        const char* name = asset->getMorphTargetNameAt(entity, i);
+        env->SetObjectArrayElement(result, (jsize) i, env->NewStringUTF(name));
+    }
+}
+
+extern "C" JNIEXPORT jint JNICALL
+Java_com_google_android_filament_gltfio_FilamentAsset_nGetMaterialVariantCount(JNIEnv*, jclass,
+        jlong nativeAsset) {
+    FilamentAsset* asset = (FilamentAsset*) nativeAsset;
+    return (jint) asset->getMaterialVariantCount();
+}
+
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_gltfio_FilamentAsset_nGetMaterialVariantNames(JNIEnv* env, jclass,
+        jlong nativeAsset, jobjectArray result) {
+    FilamentAsset* asset = (FilamentAsset*) nativeAsset;
+    for (int i = 0; i < asset->getMaterialVariantCount(); ++i) {
+        const char* name = asset->getMaterialVariantName(i);
+        env->SetObjectArrayElement(result, (jsize) i, env->NewStringUTF(name));
+    }
+}
+
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_gltfio_FilamentAsset_nApplyMaterialVariant(JNIEnv* env, jclass,
+        jlong nativeAsset, jint variantIndex) {
+    FilamentAsset* asset = (FilamentAsset*) nativeAsset;
+    asset->applyMaterialVariant(variantIndex);
+}
+
 extern "C" JNIEXPORT void JNICALL
 Java_com_google_android_filament_gltfio_FilamentAsset_nReleaseSourceData(JNIEnv* env, jclass,
         jlong nativeAsset) {

android/gltfio-android/src/main/cpp/FilamentInstance.cpp

@@ -54,3 +54,10 @@ Java_com_google_android_filament_gltfio_FilamentInstance_nGetAnimator(JNIEnv* ,
     FilamentInstance* instance = (FilamentInstance*) nativeInstance;
     return (jlong) instance->getAnimator();
 }
+
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_gltfio_FilamentInstance_nApplyMaterialVariant(JNIEnv* env, jclass,
+        jlong nativeInstance, jint variantIndex) {
+    FilamentInstance* instance = (FilamentInstance*) nativeInstance;
+    instance->applyMaterialVariant(variantIndex);
+}

android/gltfio-android/src/main/java/com/google/android/filament/gltfio/FilamentAsset.java

@@ -217,10 +217,12 @@ public class FilamentAsset {
     }
 
     /**
-     * Get the target name at target index in the given entity.
+     * Gets the names of all morph targets in the given entity.
      */
-    public String getMorphTargetNameAt(@Entity int entity, int targetIndex) {
-        return nGetMorphTargetNameAt(getNativeObject(), entity, targetIndex);
+    public @NonNull String[] getMorphTargetNames(@Entity int entity) {
+        String[] names = new String[nGetMorphTargetCount(mNativeObject, entity)];
+        nGetMorphTargetNames(mNativeObject, entity, names);
+        return names;
     }
 
     /**
@@ -232,6 +234,31 @@ public class FilamentAsset {
         return uris;
     }
 
+    /**
+     * Returns the names of all material variants.
+     */
+    public @NonNull String[] getMaterialVariantNames() {
+        String[] names = new String[nGetMaterialVariantCount(mNativeObject)];
+        nGetMaterialVariantNames(mNativeObject, names);
+        return names;
+    }
+
+    /**
+     * Applies the given material variant to all primitives that it affects.
+     *
+     * This is efficient because it merely swaps around persistent MaterialInstances. If you change
+     * a material parameter while a certain variant is active, the updated value will be remembered
+     * after you re-apply that variant.
+     *
+     * If the asset is instanced, this affects all instances in the same way.
+     * To set the variant on an individual instance, use FilamentInstance#applyMaterialVariant.
+     *
+     * Ignored if variantIndex is out of bounds.
+     */
+    public void applyMaterialVariant(@IntRange(from = 0) int variantIndex) {
+        nApplyMaterialVariant(getNativeObject(), variantIndex);
+    }
+
     /**
      * Reclaims CPU-side memory for URI strings, binding lists, and raw animation data.
      *
@@ -268,11 +295,17 @@ public class FilamentAsset {
     private static native int nGetMaterialInstanceCount(long nativeAsset);
     private static native void nGetMaterialInstances(long nativeAsset, long[] nativeResults);
 
+    private static native int nGetMaterialVariantCount(long nativeAsset);
+    private static native void nGetMaterialVariantNames(long nativeAsset, String[] result);
+
+    private static native int nGetMorphTargetCount(long nativeAsset, int entity);
+    private static native void nGetMorphTargetNames(long nativeAsset, int entity, String[] result);
+
     private static native void nGetBoundingBox(long nativeAsset, float[] box);
     private static native String nGetName(long nativeAsset, int entity);
     private static native String nGetExtras(long nativeAsset, int entity);
     private static native long nGetAnimator(long nativeAsset);
-    private static native String nGetMorphTargetNameAt(long nativeAsset, int entity, int targetIndex);
+    private static native void nApplyMaterialVariant(long nativeAsset, int variantIndex);
     private static native int nGetResourceUriCount(long nativeAsset);
     private static native void nGetResourceUris(long nativeAsset, String[] result);
     private static native void nReleaseSourceData(long nativeAsset);

android/gltfio-android/src/main/java/com/google/android/filament/gltfio/FilamentInstance.java

@@ -16,6 +16,7 @@
 
 package com.google.android.filament.gltfio;
 
+import androidx.annotation.IntRange;
 import androidx.annotation.NonNull;
 
 import com.google.android.filament.Entity;
@@ -84,8 +85,18 @@ public class FilamentInstance {
         return mAnimator;
     }
 
+    /**
+     * Applies the given material variant to all primitives in this instance.
+     *
+     * Ignored if variantIndex is out of bounds.
+     */
+    void applyMaterialVariant(@IntRange(from = 0) int variantIndex) {
+        nApplyMaterialVariant(mNativeObject, variantIndex);
+    }
+
     private static native int nGetRoot(long nativeAsset);
     private static native int nGetEntityCount(long nativeAsset);
     private static native void nGetEntities(long nativeAsset, int[] result);
     private static native long nGetAnimator(long nativeAsset);
+    private static native void nApplyMaterialVariant(long nativeAsset, int variantIndex);
 }

android/gradle.properties

@@ -1,5 +1,5 @@
 GROUP=com.google.android.filament
-VERSION_NAME=1.20.5
+VERSION_NAME=1.21.1
 
 POM_DESCRIPTION=Real-time physically based rendering engine for Android.
 

build.sh

@@ -487,8 +487,7 @@ function build_android {
             cp gltfio-android/build/outputs/aar/gltfio-android-full-debug.aar ../out/gltfio-android-debug.aar
 
             echo "Installing out/filament-utils-android-debug.aar..."
-            cp filament-utils-android/build/outputs/aar/filament-utils-android-lite-debug.aar ../out/
-            cp filament-utils-android/build/outputs/aar/filament-utils-android-full-debug.aar ../out/filament-utils-android-debug.aar
+            cp filament-utils-android/build/outputs/aar/filament-utils-android-debug.aar ../out/filament-utils-android-debug.aar
 
             if [[ "${BUILD_ANDROID_SAMPLES}" == "true" ]]; then
                 for sample in ${ANDROID_SAMPLES}; do
@@ -536,8 +535,7 @@ function build_android {
             cp gltfio-android/build/outputs/aar/gltfio-android-full-release.aar ../out/gltfio-android-release.aar
 
             echo "Installing out/filament-utils-android-release.aar..."
-            cp filament-utils-android/build/outputs/aar/filament-utils-android-lite-release.aar ../out/
-            cp filament-utils-android/build/outputs/aar/filament-utils-android-full-release.aar ../out/filament-utils-android-release.aar
+            cp filament-utils-android/build/outputs/aar/filament-utils-android-release.aar ../out/filament-utils-android-release.aar
 
             if [[ "${BUILD_ANDROID_SAMPLES}" == "true" ]]; then
                 for sample in ${ANDROID_SAMPLES}; do

build/common/requirements.txt

@@ -0,0 +1,14 @@
+setuptools==40.6.2
+wheel==0.37.1
+certifi==2021.10.8
+cffi==1.15.0
+charset-normalizer==2.0.12
+Deprecated==1.2.13
+idna==3.3
+pycparser==2.21
+PyGithub==1.55
+PyJWT==2.3.0
+PyNaCl==1.5.0
+requests==2.27.1
+urllib3==1.26.9
+wrapt==1.14.0

build/common/upload-assets.py

@@ -12,6 +12,25 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
+# requirements.txt created via:
+#
+# pip3 install virtualenv
+# python3 -m venv env
+# pip3 install PyGithub
+# pip3 install wheel
+# --all includes wheel and setuputils, which is needed for GitHub Actions
+# pip3 freeze --all > requirements.txt
+# Manually move 'setuptools' and 'wheel' lines to the beginning of the file.
+# Manually remove the 'pip' line.
+#
+# Requirements are installed in GitHub Actions via:
+# xargs -L 1 sudo pip3 install < build/common/requirements.txt
+# xargs must be used because the ordering of the dependencies matters (namely, setuptools).
+# sudo must be used to uninstall non-matching versions of packages.
+# pip is removed to avoid conflicts with the pre-installed pip version on Actions.
+# This technique does not work with Windows, unfortunately.
+
 from github import Github
 import os, sys
 

docs/webgl/helmet.html

@@ -113,7 +113,7 @@ class App {
         this.view = engine.createView();
         this.view.setVignetteOptions({ midPoint: 0.8, enabled: true });
 
-        this.view.setBloomOptions({ stength: 0.2, enabled: true });
+        this.view.setBloomOptions({ strength: 0.2, enabled: true });
 
         this.view.setCamera(this.camera);
         this.view.setScene(this.scene);

filament/CMakeLists.txt

@@ -92,7 +92,6 @@ set(SRCS
         src/UniformBuffer.cpp
         src/VertexBuffer.cpp
         src/View.cpp
-        src/Viewport.cpp
         src/components/CameraManager.cpp
         src/components/LightManager.cpp
         src/components/RenderableManager.cpp
@@ -118,14 +117,14 @@ set(SRCS
         src/details/Texture.cpp
         src/details/VertexBuffer.cpp
         src/details/View.cpp
-        src/fg2/Blackboard.cpp
-        src/fg2/DependencyGraph.cpp
-        src/fg2/FrameGraph.cpp
-        src/fg2/FrameGraphPass.cpp
-        src/fg2/FrameGraphResources.cpp
-        src/fg2/FrameGraphTexture.cpp
-        src/fg2/PassNode.cpp
-        src/fg2/ResourceNode.cpp
+        src/fg/Blackboard.cpp
+        src/fg/DependencyGraph.cpp
+        src/fg/FrameGraph.cpp
+        src/fg/FrameGraphPass.cpp
+        src/fg/FrameGraphResources.cpp
+        src/fg/FrameGraphTexture.cpp
+        src/fg/PassNode.cpp
+        src/fg/ResourceNode.cpp
         src/fsr.cpp
 )
 
@@ -177,19 +176,19 @@ set(PRIVATE_HDRS
         src/details/Texture.h
         src/details/VertexBuffer.h
         src/details/View.h
-        src/fg2/Blackboard.h
-        src/fg2/FrameGraph.h
-        src/fg2/FrameGraphId.h
-        src/fg2/FrameGraphPass.h
-        src/fg2/FrameGraphRenderPass.h
-        src/fg2/FrameGraphResources.h
-        src/fg2/FrameGraphTexture.h
-        src/fg2/Resource.cpp
-        src/fg2/details/DependencyGraph.h
-        src/fg2/details/PassNode.h
-        src/fg2/details/Resource.h
-        src/fg2/details/ResourceNode.h
-        src/fg2/details/Utilities.h
+        src/fg/Blackboard.h
+        src/fg/FrameGraph.h
+        src/fg/FrameGraphId.h
+        src/fg/FrameGraphPass.h
+        src/fg/FrameGraphRenderPass.h
+        src/fg/FrameGraphResources.h
+        src/fg/FrameGraphTexture.h
+        src/fg/Resource.cpp
+        src/fg/details/DependencyGraph.h
+        src/fg/details/PassNode.h
+        src/fg/details/Resource.h
+        src/fg/details/ResourceNode.h
+        src/fg/details/Utilities.h
         src/fsr.h
         src/materials/fsr/ffx_a.h
         src/materials/fsr/ffx_fsr1.h

filament/backend/CMakeLists.txt

@@ -13,7 +13,6 @@ set(PUBLIC_HDRS
         include/backend/CallbackHandler.h
         include/backend/DriverEnums.h
         include/backend/Handle.h
-        include/backend/ShaderStageFlags.h
         include/backend/PipelineState.h
         include/backend/PixelBufferDescriptor.h
         include/backend/Platform.h
@@ -75,8 +74,8 @@ if (FILAMENT_SUPPORTS_OPENGL AND NOT FILAMENT_USE_EXTERNAL_GLES3 AND NOT FILAMEN
             src/opengl/OpenGLProgram.cpp
             src/opengl/OpenGLProgram.h
             src/opengl/OpenGLPlatform.cpp
-            src/opengl/TimerQuery.cpp
-            src/opengl/TimerQuery.h
+            src/opengl/OpenGLTimerQuery.cpp
+            src/opengl/OpenGLTimerQuery.h
             include/private/backend/OpenGLPlatform.h
     )
     if (EGL)

filament/backend/include/backend/DriverEnums.h

@@ -142,9 +142,9 @@ struct Viewport {
     uint32_t width;     //!< width in pixels
     uint32_t height;    //!< height in pixels
     //! get the right coordinate in window space of the viewport
-    int32_t right() const noexcept { return left + width; }
+    int32_t right() const noexcept { return left + int32_t(width); }
     //! get the top coordinate in window space of the viewport
-    int32_t top() const noexcept { return bottom + height; }
+    int32_t top() const noexcept { return bottom + int32_t(height); }
 };
 
 /**
@@ -906,6 +906,16 @@ enum ShaderType : uint8_t {
 };
 static constexpr size_t PIPELINE_STAGE_COUNT = 2;
 
+struct ShaderStageFlags {
+    bool vertex : 1;
+    bool fragment : 1;
+    bool hasShaderType(ShaderType type) const {
+        return (vertex && type == ShaderType::VERTEX) ||
+               (fragment && type == ShaderType::FRAGMENT);
+    }
+};
+static constexpr ShaderStageFlags ALL_SHADER_STAGE_FLAGS = { .vertex = true, .fragment = true };
+
 /**
  * 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.
@@ -1026,6 +1036,7 @@ utils::io::ostream& operator<<(utils::io::ostream& out, const filament::backend:
 utils::io::ostream& operator<<(utils::io::ostream& out, const filament::backend::RasterState& rs);
 utils::io::ostream& operator<<(utils::io::ostream& out, const filament::backend::RenderPassParams& b);
 utils::io::ostream& operator<<(utils::io::ostream& out, const filament::backend::Viewport& v);
+utils::io::ostream& operator<<(utils::io::ostream& out, filament::backend::ShaderStageFlags stageFlags);
 #endif
 
 #endif // TNT_FILAMENT_BACKEND_DRIVERENUMS_H

filament/backend/include/backend/ShaderStageFlags.h

@@ -1,52 +0,0 @@
-/*
- * Copyright (C) 2022 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_SHADERSTAGEFLAGS_H
-#define TNT_FILAMENT_BACKEND_SHADERSTAGEFLAGS_H
-
-#include <backend/DriverEnums.h>
-
-namespace filament::backend {
-
-struct ShaderStageFlags {
-    bool vertex : 1;
-    bool fragment : 1;
-
-    inline bool hasShaderType(ShaderType type) const {
-        return (vertex && type == ShaderType::VERTEX) ||
-               (fragment && type == ShaderType::FRAGMENT);
-    }
-};
-
-constexpr ShaderStageFlags ALL_SHADER_STAGE_FLAGS = { .vertex = true, .fragment = true };
-
-inline utils::io::ostream& operator<<(utils::io::ostream& stream, ShaderStageFlags stageFlags) {
-    stream << "{ ";
-    if (stageFlags.vertex) {
-        stream << "vertex";
-    }
-    if (stageFlags.fragment) {
-        if (stageFlags.vertex)
-            stream << " | ";
-        stream << "fragment";
-    }
-    stream << " }";
-    return stream;
-}
-
-} // namespace filament
-
-#endif // TNT_FILAMENT_BACKEND_SHADERSTAGEFLAGS_H

filament/backend/include/private/backend/Program.h

@@ -25,7 +25,6 @@
 #include <utils/ostream.h>
 
 #include <backend/DriverEnums.h>
-#include <backend/ShaderStageFlags.h>
 
 #include <array>
 
@@ -94,13 +93,15 @@ public:
     }
 
     using ShaderBlob = utils::FixedCapacityVector<uint8_t>;
-    std::array<ShaderBlob, SHADER_TYPE_COUNT> const& getShadersSource() const noexcept {
-        return mShadersSource;
-    }
+    using ShaderSource = std::array<ShaderBlob, SHADER_TYPE_COUNT>;
+    ShaderSource const& getShadersSource() const noexcept { return mShadersSource; }
+    ShaderSource& getShadersSource() noexcept { return mShadersSource; }
 
     UniformBlockInfo const& getUniformBlockInfo() const noexcept { return mUniformBlocks; }
+    UniformBlockInfo& getUniformBlockInfo() noexcept { return mUniformBlocks; }
 
     SamplerGroupInfo const& getSamplerGroupInfo() const { return mSamplerGroups; }
+    SamplerGroupInfo& getSamplerGroupInfo() { return mSamplerGroups; }
 
     const utils::CString& getName() const noexcept { return mName; }
 
@@ -111,7 +112,7 @@ private:
 
     UniformBlockInfo mUniformBlocks = {};
     SamplerGroupInfo mSamplerGroups = {};
-    std::array<ShaderBlob, SHADER_TYPE_COUNT> mShadersSource;
+    ShaderSource mShadersSource;
     bool mHasSamplers = false;
     utils::CString mName;
     utils::Invocable<utils::io::ostream&(utils::io::ostream& out)> mLogger;

filament/backend/src/DriverBase.h

@@ -98,12 +98,8 @@ struct HwRenderPrimitive : public HwBase {
 };
 
 struct HwProgram : public HwBase {
-#ifndef NDEBUG
     utils::CString name;
     explicit HwProgram(utils::CString name) noexcept : name(std::move(name)) { }
-#else
-    explicit HwProgram(const utils::CString&) noexcept { }
-#endif
     HwProgram() noexcept = default;
 };
 

filament/backend/src/Handle.cpp

@@ -28,7 +28,7 @@ namespace filament::backend {
 
 #ifndef NDEBUG
 
-static char const * const kOurNamespace = "filament::";
+static char const * const kOurNamespace = "filament::backend";
 
 // removes all occurrences of "what" from "str"
 UTILS_NOINLINE

filament/backend/src/android/ExternalTextureManagerAndroid.cpp

@@ -25,8 +25,7 @@
 
 using namespace utils;
 
-namespace filament {
-using namespace backend;
+namespace filament::backend {
 
 template <typename T>
 static void loadSymbol(T*& pfn, const char *symbol) noexcept {
@@ -111,7 +110,7 @@ ExternalTextureManagerAndroid::~ExternalTextureManagerAndroid() noexcept {
 }
 
 // called on gl thread
-backend::Platform::ExternalTexture* ExternalTextureManagerAndroid::createExternalTexture() noexcept {
+Platform::ExternalTexture* ExternalTextureManagerAndroid::createExternalTexture() noexcept {
     if (__builtin_available(android 26, *)) {
     } else {
         // initialize java stuff on-demand
@@ -132,21 +131,21 @@ backend::Platform::ExternalTexture* ExternalTextureManagerAndroid::createExterna
 
 // called on app thread
 void ExternalTextureManagerAndroid::reallocate(
-        backend::Platform::ExternalTexture* ets, uint32_t w, uint32_t h,
-        backend::TextureFormat format, uint64_t usage) noexcept {
+        Platform::ExternalTexture* ets, uint32_t w, uint32_t h,
+        TextureFormat format, uint64_t usage) noexcept {
     destroyStorage(ets);
     alloc(ets, w, h, format, usage);
 }
 
 // called on gl thread
-void ExternalTextureManagerAndroid::destroy(backend::Platform::ExternalTexture* ets) noexcept {
+void ExternalTextureManagerAndroid::destroy(Platform::ExternalTexture* ets) noexcept {
     destroyStorage(ets);
     delete static_cast<EGLExternalTexture*>(ets);
 }
 
 // called on app thread
 void ExternalTextureManagerAndroid::alloc(
-        backend::Platform::ExternalTexture* t,
+        Platform::ExternalTexture* t,
         uint32_t w, uint32_t h, TextureFormat format, uint64_t usage) noexcept {
 
     EGLExternalTexture* ets = static_cast<EGLExternalTexture*>(t);
@@ -200,7 +199,7 @@ void ExternalTextureManagerAndroid::alloc(
 }
 
 // called on gl thread
-void ExternalTextureManagerAndroid::destroyStorage(backend::Platform::ExternalTexture* t) noexcept {
+void ExternalTextureManagerAndroid::destroyStorage(Platform::ExternalTexture* t) noexcept {
         EGLExternalTexture* ets = static_cast<EGLExternalTexture*>(t);
     if (__builtin_available(android 26, *)) {
         // destroy the current storage if any
@@ -219,5 +218,5 @@ void ExternalTextureManagerAndroid::destroyStorage(backend::Platform::ExternalTe
     }
 }
 
-} // namespace filament
+} // namespace filament::backend
 

filament/backend/src/android/ExternalTextureManagerAndroid.h

@@ -25,7 +25,7 @@
 #include <android/api-level.h>
 #include <android/hardware_buffer.h>
 
-namespace filament {
+namespace filament::backend {
 
 /*
  * ExternalTextureManagerAndroid::ExternalTexture is basically a wrapper for AHardwareBuffer.
@@ -39,7 +39,7 @@ namespace filament {
 class ExternalTextureManagerAndroid {
 public:
 
-    struct ExternalTexture : public backend::Platform::ExternalTexture {
+    struct ExternalTexture : public Platform::ExternalTexture {
         void* clientBuffer = nullptr;
         AHardwareBuffer* hardwareBuffer = nullptr;
     };
@@ -51,26 +51,26 @@ public:
     static void destroy(ExternalTextureManagerAndroid* pExternalTextureManager) noexcept;
 
     // must be called on backend thread (only because we don't synchronize
-    backend::Platform::ExternalTexture* createExternalTexture() noexcept;
+    Platform::ExternalTexture* createExternalTexture() noexcept;
 
     // called on app thread
     void reallocate(
-        backend::Platform::ExternalTexture* ets, uint32_t w, uint32_t h,
-        backend::TextureFormat format, uint64_t usage) noexcept;
+        Platform::ExternalTexture* ets, uint32_t w, uint32_t h,
+        TextureFormat format, uint64_t usage) noexcept;
 
     // must be called on backend thread
-    void destroy(backend::Platform::ExternalTexture* ets) noexcept;
+    void destroy(Platform::ExternalTexture* ets) noexcept;
 
 private:
     ExternalTextureManagerAndroid() noexcept;
     ~ExternalTextureManagerAndroid() noexcept;
 
     // called on app thread
-    void alloc(backend::Platform::ExternalTexture* ets,
-               uint32_t w, uint32_t h, backend::TextureFormat format, uint64_t usage) noexcept;
+    void alloc(Platform::ExternalTexture* ets,
+               uint32_t w, uint32_t h, TextureFormat format, uint64_t usage) noexcept;
 
     // called on gl thread
-    void destroyStorage(backend::Platform::ExternalTexture* ets) noexcept;
+    void destroyStorage(Platform::ExternalTexture* ets) noexcept;
 
     VirtualMachineEnv& mVm;
 
@@ -79,8 +79,6 @@ private:
     jmethodID mGraphicBuffer_nDestroyGraphicBuffer = nullptr;
 };
 
-
-
-} // namespace filament
+} // namespace filament::backend
 
 #endif // TNT_FILAMENT_DRIVER_ANDROID_EXTERNAL_TEXTURE_MANAGER_ANDROID_H

filament/backend/src/metal/MetalBlitter.h

@@ -26,7 +26,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 struct MetalContext;
 
@@ -45,7 +44,7 @@ public:
             uint32_t slice = 0;      // must be 0 on source attachment
         };
 
-        // Valid source formats:       2D, 2DMultisample, 3D
+        // Valid source formats:       2D, 2DArray, 2DMultisample, 3D
         // Valid destination formats:  2D, 2DArray, 3D, Cube
         Attachment source, destination;
         SamplerMagFilter filter;
@@ -133,7 +132,6 @@ private:
 
 };
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalBlitter.mm

@@ -17,12 +17,12 @@
 #include "MetalBlitter.h"
 
 #include "MetalContext.h"
+#include "MetalUtils.h"
 
 #include <utils/Panic.h>
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 static const char* functionLibrary = R"(
 #include <metal_stdlib>
@@ -145,8 +145,6 @@ void MetalBlitter::blit(id<MTLCommandBuffer> cmdBuffer, const BlitArgs& args) {
     bool blitColor = args.blitColor();
     bool blitDepth = args.blitDepth();
 
-    ASSERT_PRECONDITION(args.source.slice == 0u, "Source attachment must have slice of 0.");
-
     ASSERT_PRECONDITION(args.source.region.size.depth == args.destination.region.size.depth,
             "Blitting requires the source and destination regions to have the same depth.");
 
@@ -223,7 +221,7 @@ void MetalBlitter::blitFastPath(id<MTLCommandBuffer> cmdBuffer, bool& blitColor,
 
             id<MTLBlitCommandEncoder> blitEncoder = [cmdBuffer blitCommandEncoder];
             [blitEncoder copyFromTexture:args.source.color
-                             sourceSlice:0
+                             sourceSlice:args.source.slice
                              sourceLevel:args.source.level
                             sourceOrigin:args.source.region.origin
                               sourceSize:args.source.region.size
@@ -244,7 +242,7 @@ void MetalBlitter::blitFastPath(id<MTLCommandBuffer> cmdBuffer, bool& blitColor,
 
             id<MTLBlitCommandEncoder> blitEncoder = [cmdBuffer blitCommandEncoder];
             [blitEncoder copyFromTexture:args.source.depth
-                             sourceSlice:0
+                             sourceSlice:args.source.slice
                              sourceLevel:args.source.level
                             sourceOrigin:args.source.region.origin
                               sourceSize:args.source.region.size
@@ -301,7 +299,7 @@ void MetalBlitter::blitDepthPlane(id<MTLCommandBuffer> cmdBuffer, bool blitColor
     }
     id<MTLFunction> fragmentFunction = getBlitFragmentFunction(key);
 
-    PipelineState pipelineState {
+    MetalPipelineState pipelineState {
         .vertexFunction = getBlitVertexFunction(),
         .fragmentFunction = fragmentFunction,
         .vertexDescription = {},
@@ -323,12 +321,22 @@ void MetalBlitter::blitDepthPlane(id<MTLCommandBuffer> cmdBuffer, bool blitColor
     id<MTLRenderPipelineState> pipeline = mContext.pipelineStateCache.getOrCreateState(pipelineState);
     [encoder setRenderPipelineState:pipeline];
 
+    // For texture arrays, create a view of the texture at the given slice (layer).
+    id<MTLTexture> srcTextureColor = args.source.color;
+    if (srcTextureColor && srcTextureColor.textureType == MTLTextureType2DArray) {
+        srcTextureColor = createTextureViewWithSingleSlice(srcTextureColor, args.source.slice);
+    }
+    id<MTLTexture> srcTextureDepth = args.source.depth;
+    if (srcTextureDepth && srcTextureDepth.textureType == MTLTextureType2DArray) {
+        srcTextureDepth = createTextureViewWithSingleSlice(srcTextureDepth, args.source.slice);
+    }
+
     if (blitColor) {
-        [encoder setFragmentTexture:args.source.color atIndex:0];
+        [encoder setFragmentTexture:srcTextureColor atIndex:0];
     }
 
     if (blitDepth) {
-        [encoder setFragmentTexture:args.source.depth atIndex:1];
+        [encoder setFragmentTexture:srcTextureDepth atIndex:1];
     }
 
     SamplerMinFilter filterMin = SamplerMinFilter::NEAREST_MIPMAP_NEAREST;
@@ -521,6 +529,5 @@ id<MTLFunction> MetalBlitter::getBlitFragmentFunction(BlitFunctionKey key) {
     return function;
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalBuffer.h

@@ -26,7 +26,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 class MetalBuffer {
 public:
@@ -94,7 +93,6 @@ private:
     void copyIntoStreamBuffer(void* src, size_t size);
 };
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalBuffer.mm

@@ -22,7 +22,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 MetalBuffer::MetalBuffer(MetalContext& context, BufferUsage usage, size_t size, bool forceGpuBuffer)
         : mBufferSize(size), mContext(context) {
@@ -206,6 +205,5 @@ void MetalBuffer::bindBuffers(id<MTLCommandBuffer> cmdBuffer, id<MTLRenderComman
     }
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalBufferPool.h

@@ -25,7 +25,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 struct MetalContext;
 
@@ -78,7 +77,6 @@ private:
     static constexpr uint32_t TIME_BEFORE_EVICTION = 10;
 };
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalBufferPool.mm

@@ -26,7 +26,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 MetalBufferPoolEntry const* MetalBufferPool::acquireBuffer(size_t numBytes) {
     std::lock_guard<std::mutex> lock(mMutex);
@@ -110,6 +109,5 @@ void MetalBufferPool::reset() noexcept {
     mFreeStages.clear();
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalContext.h

@@ -36,14 +36,13 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 class MetalDriver;
 class MetalBlitter;
 class MetalBufferPool;
 class MetalRenderTarget;
 class MetalSwapChain;
-class TimerQueryInterface;
+class MetalTimerQueryInterface;
 struct MetalUniformBuffer;
 struct MetalIndexBuffer;
 struct MetalSamplerGroup;
@@ -113,7 +112,7 @@ struct MetalContext {
     MTLSharedEventListener* eventListener = nil;
     uint64_t signalId = 1;
 
-    TimerQueryInterface* timerQueryImpl;
+    MetalTimerQueryInterface* timerQueryImpl;
 
     std::stack<const char*> groupMarkers;
 
@@ -134,7 +133,6 @@ id<MTLTexture> getOrCreateEmptyTexture(MetalContext* context);
 
 bool isInRenderPass(MetalContext* context);
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalContext.mm

@@ -25,7 +25,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 void initializeSupportedGpuFamilies(MetalContext* context) {
     auto& highestSupportedFamily = context->highestSupportedGpuFamily;
@@ -145,6 +144,5 @@ bool isInRenderPass(MetalContext* context) {
     return context->currentRenderPassEncoder != nil;
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalDriver.h

@@ -31,8 +31,6 @@ namespace backend {
 
 class MetalPlatform;
 
-namespace metal {
-
 class MetalBuffer;
 struct MetalUniformBuffer;
 struct MetalContext;
@@ -44,17 +42,17 @@ struct UniformBufferState;
 #endif
 
 class MetalDriver final : public DriverBase {
-    explicit MetalDriver(backend::MetalPlatform* platform) noexcept;
+    explicit MetalDriver(MetalPlatform* platform) noexcept;
     ~MetalDriver() noexcept override;
 
 public:
-    static Driver* create(backend::MetalPlatform* platform);
+    static Driver* create(MetalPlatform* platform);
 
 private:
 
     friend class MetalSwapChain;
 
-    backend::MetalPlatform& mPlatform;
+    MetalPlatform& mPlatform;
 
     MetalContext* mContext;
 
@@ -68,7 +66,7 @@ private:
      */
 
     template<typename T>
-    friend class backend::ConcreteDispatcher;
+    friend class ConcreteDispatcher;
 
 #define DECL_DRIVER_API(methodName, paramsDecl, params) \
     UTILS_ALWAYS_INLINE inline void methodName(paramsDecl);
@@ -86,7 +84,7 @@ private:
      * Memory management
      */
 
-    backend::HandleAllocatorMTL mHandleAllocator;
+    HandleAllocatorMTL mHandleAllocator;
 
     template<typename D>
     Handle<D> alloc_handle() {
@@ -126,7 +124,6 @@ private:
 
 };
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalDriver.mm

@@ -41,18 +41,16 @@ namespace filament {
 namespace backend {
 
 Driver* MetalDriverFactory::create(MetalPlatform* const platform) {
-    return metal::MetalDriver::create(platform);
+    return MetalDriver::create(platform);
 }
 
-namespace metal {
-
 UTILS_NOINLINE
 Driver* MetalDriver::create(MetalPlatform* const platform) {
     assert_invariant(platform);
     return new MetalDriver(platform);
 }
 
-MetalDriver::MetalDriver(backend::MetalPlatform* platform) noexcept
+MetalDriver::MetalDriver(MetalPlatform* platform) noexcept
         : DriverBase(new ConcreteDispatcher<MetalDriver>()),
         mPlatform(*platform),
         mContext(new MetalContext),
@@ -108,7 +106,7 @@ MetalDriver::MetalDriver(backend::MetalPlatform* platform) noexcept
     mContext->blitter = new MetalBlitter(*mContext);
 
     if (@available(iOS 12, *)) {
-        mContext->timerQueryImpl = new TimerQueryFence(*mContext);
+        mContext->timerQueryImpl = new MetalTimerQueryFence(*mContext);
     } else {
         mContext->timerQueryImpl = new TimerQueryNoop();
     }
@@ -149,13 +147,13 @@ void MetalDriver::beginFrame(int64_t monotonic_clock_ns, uint32_t frameId) {
 }
 
 void MetalDriver::setFrameScheduledCallback(Handle<HwSwapChain> sch,
-        backend::FrameScheduledCallback callback, void* user) {
+        FrameScheduledCallback callback, void* user) {
     auto* swapChain = handle_cast<MetalSwapChain>(sch);
     swapChain->setFrameScheduledCallback(callback, user);
 }
 
 void MetalDriver::setFrameCompletedCallback(Handle<HwSwapChain> sch,
-        backend::FrameCompletedCallback callback, void* user) {
+        FrameCompletedCallback callback, void* user) {
     auto* swapChain = handle_cast<MetalSwapChain>(sch);
     swapChain->setFrameCompletedCallback(callback, user);
 }
@@ -291,7 +289,7 @@ void MetalDriver::createDefaultRenderTargetR(Handle<HwRenderTarget> rth, int dum
 
 void MetalDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
         TargetBufferFlags targetBufferFlags, uint32_t width, uint32_t height,
-        uint8_t samples, backend::MRT color,
+        uint8_t samples, MRT color,
         TargetBufferInfo depth, TargetBufferInfo stencil) {
     // Clamp sample count to what the device supports.
     auto& sc = mContext->sampleCountLookup;
@@ -344,7 +342,7 @@ void MetalDriver::createSyncR(Handle<HwSync> sh, int) {
 }
 
 void MetalDriver::createSwapChainR(Handle<HwSwapChain> sch, void* nativeWindow, uint64_t flags) {
-    if (UTILS_UNLIKELY(flags & backend::SWAP_CHAIN_CONFIG_APPLE_CVPIXELBUFFER)) {
+    if (UTILS_UNLIKELY(flags & SWAP_CHAIN_CONFIG_APPLE_CVPIXELBUFFER)) {
         CVPixelBufferRef pixelBuffer = (CVPixelBufferRef) nativeWindow;
         construct_handle<MetalSwapChain>(sch, *mContext, pixelBuffer, flags);
     } else {
@@ -569,7 +567,7 @@ Handle<HwStream> MetalDriver::createStreamAcquired() {
 }
 
 void MetalDriver::setAcquiredImage(Handle<HwStream> sh, void* image,
-        backend::CallbackHandler* handler, backend::StreamCallback cb, void* userData) {
+        CallbackHandler* handler, StreamCallback cb, void* userData) {
 }
 
 void MetalDriver::setStreamDimensions(Handle<HwStream> stream, uint32_t width,
@@ -581,7 +579,7 @@ int64_t MetalDriver::getStreamTimestamp(Handle<HwStream> stream) {
     return 0;
 }
 
-void MetalDriver::updateStreams(backend::DriverApi* driver) {
+void MetalDriver::updateStreams(DriverApi* driver) {
 
 }
 
@@ -1058,8 +1056,8 @@ void MetalDriver::readStreamPixels(Handle<HwStream> sh, uint32_t x, uint32_t y,
 }
 
 void MetalDriver::blit(TargetBufferFlags buffers,
-        Handle<HwRenderTarget> dst, backend::Viewport dstRect,
-        Handle<HwRenderTarget> src, backend::Viewport srcRect,
+        Handle<HwRenderTarget> dst, Viewport dstRect,
+        Handle<HwRenderTarget> src, Viewport srcRect,
         SamplerMagFilter filter) {
     // If we're the in middle of a render pass, finish it.
     // This condition should only occur during copyFrame. It's okay to end the render pass because
@@ -1099,7 +1097,8 @@ void MetalDriver::blit(TargetBufferFlags buffers,
             dstRect.width, dstRect.height);
 
     auto isBlitableTextureType = [](MTLTextureType t) {
-        return t == MTLTextureType2D || t == MTLTextureType2DMultisample;
+        return t == MTLTextureType2D || t == MTLTextureType2DMultisample ||
+               t == MTLTextureType2DArray;
     };
 
     MetalBlitter::BlitArgs args;
@@ -1121,6 +1120,8 @@ void MetalDriver::blit(TargetBufferFlags buffers,
             args.destination.color = dstColorAttachment.getTexture();
             args.source.level = srcColorAttachment.level;
             args.destination.level = dstColorAttachment.level;
+            args.source.slice = srcColorAttachment.layer;
+            args.destination.slice = dstColorAttachment.layer;
         }
     }
 
@@ -1137,25 +1138,33 @@ void MetalDriver::blit(TargetBufferFlags buffers,
             args.destination.depth = dstDepthAttachment.getTexture();
 
             if (args.blitColor()) {
-                // If blitting color, we've already set the source and destination levels.
-                // Check that they match the requested depth levels.
+                // If blitting color, we've already set the source and destination levels and slices.
+                // Check that they match the requested depth levels/slices.
                 ASSERT_PRECONDITION(args.source.level == srcDepthAttachment.level,
                                    "Color and depth source LOD must match. (%d != %d)",
                                    args.source.level, srcDepthAttachment.level);
                 ASSERT_PRECONDITION(args.destination.level == dstDepthAttachment.level,
                                    "Color and depth destination LOD must match. (%d != %d)",
                                    args.destination.level, dstDepthAttachment.level);
+                ASSERT_PRECONDITION(args.source.slice == srcDepthAttachment.layer,
+                        "Color and depth source layer must match. (%d != %d)",
+                        args.source.slice, srcDepthAttachment.layer);
+                ASSERT_PRECONDITION(args.destination.slice == dstDepthAttachment.layer,
+                        "Color and depth destination layer must match. (%d != %d)",
+                        args.destination.slice, dstDepthAttachment.layer);
             }
 
             args.source.level = srcDepthAttachment.level;
             args.destination.level = dstDepthAttachment.level;
+            args.source.slice = srcDepthAttachment.layer;
+            args.destination.slice = dstDepthAttachment.layer;
         }
     }
 
     mContext->blitter->blit(getPendingCommandBuffer(mContext), args);
 }
 
-void MetalDriver::draw(backend::PipelineState ps, Handle<HwRenderPrimitive> rph, uint32_t instanceCount) {
+void MetalDriver::draw(PipelineState ps, Handle<HwRenderPrimitive> rph, uint32_t instanceCount) {
     ASSERT_PRECONDITION(mContext->currentRenderPassEncoder != nullptr,
             "Attempted to draw without a valid command encoder.");
     auto primitive = handle_cast<MetalRenderPrimitive>(rph);
@@ -1185,7 +1194,7 @@ void MetalDriver::draw(backend::PipelineState ps, Handle<HwRenderPrimitive> rph,
     if (depthAttachment) {
         depthPixelFormat = depthAttachment.getPixelFormat();
     }
-    metal::PipelineState pipelineState {
+    MetalPipelineState pipelineState {
         .vertexFunction = program->vertexFunction,
         .fragmentFunction = program->fragmentFunction,
         .vertexDescription = primitive->vertexDescription,
@@ -1293,15 +1302,15 @@ void MetalDriver::draw(backend::PipelineState ps, Handle<HwRenderPrimitive> rph,
         return mContext->samplerStateCache.getOrCreateState(s);
     };
 
-    id<MTLTexture> texturesToBindVertex[backend::MAX_VERTEX_SAMPLER_COUNT] = {};
-    id<MTLSamplerState> samplersToBindVertex[backend::MAX_VERTEX_SAMPLER_COUNT] = {};
+    id<MTLTexture> texturesToBindVertex[MAX_VERTEX_SAMPLER_COUNT] = {};
+    id<MTLSamplerState> samplersToBindVertex[MAX_VERTEX_SAMPLER_COUNT] = {};
 
     enumerateSamplerGroups(program, ShaderType::VERTEX,
             [this, &getTextureToBind, &getSamplerToBind, &texturesToBindVertex, &samplersToBindVertex](
                     const SamplerGroup::Sampler* sampler, uint8_t binding) {
         // We currently only support a max of MAX_VERTEX_SAMPLER_COUNT samplers. Ignore any additional
         // samplers that may be bound.
-        if (binding >= backend::MAX_VERTEX_SAMPLER_COUNT) {
+        if (binding >= MAX_VERTEX_SAMPLER_COUNT) {
             return;
         }
 
@@ -1325,21 +1334,21 @@ void MetalDriver::draw(backend::PipelineState ps, Handle<HwRenderPrimitive> rph,
         }
     }
 
-    NSRange vertexSamplerRange = NSMakeRange(0, backend::MAX_VERTEX_SAMPLER_COUNT);
+    NSRange vertexSamplerRange = NSMakeRange(0, MAX_VERTEX_SAMPLER_COUNT);
     [mContext->currentRenderPassEncoder setVertexTextures:texturesToBindVertex
                                                 withRange:vertexSamplerRange];
     [mContext->currentRenderPassEncoder setVertexSamplerStates:samplersToBindVertex
                                                      withRange:vertexSamplerRange];
 
-    id<MTLTexture> texturesToBindFragment[backend::MAX_FRAGMENT_SAMPLER_COUNT] = {};
-    id<MTLSamplerState> samplersToBindFragment[backend::MAX_FRAGMENT_SAMPLER_COUNT] = {};
+    id<MTLTexture> texturesToBindFragment[MAX_FRAGMENT_SAMPLER_COUNT] = {};
+    id<MTLSamplerState> samplersToBindFragment[MAX_FRAGMENT_SAMPLER_COUNT] = {};
 
     enumerateSamplerGroups(program, ShaderType::FRAGMENT,
             [this, &getTextureToBind, &getSamplerToBind, &texturesToBindFragment, &samplersToBindFragment](
                     const SamplerGroup::Sampler* sampler, uint8_t binding) {
         // We currently only support a max of MAX_FRAGMENT_SAMPLER_COUNT samplers. Ignore any additional
         // samplers that may be bound.
-        if (binding >= backend::MAX_FRAGMENT_SAMPLER_COUNT) {
+        if (binding >= MAX_FRAGMENT_SAMPLER_COUNT) {
             return;
         }
 
@@ -1363,7 +1372,7 @@ void MetalDriver::draw(backend::PipelineState ps, Handle<HwRenderPrimitive> rph,
         }
     }
 
-    NSRange fragmentSamplerRange = NSMakeRange(0, backend::MAX_FRAGMENT_SAMPLER_COUNT);
+    NSRange fragmentSamplerRange = NSMakeRange(0, MAX_FRAGMENT_SAMPLER_COUNT);
     [mContext->currentRenderPassEncoder setFragmentTextures:texturesToBindFragment
                                                   withRange:fragmentSamplerRange];
     [mContext->currentRenderPassEncoder setFragmentSamplerStates:samplersToBindFragment
@@ -1468,10 +1477,8 @@ void MetalDriver::enumerateBoundUniformBuffers(
     }
 }
 
-} // namespace metal
-
 // explicit instantiation of the Dispatcher
-template class ConcreteDispatcher<metal::MetalDriver>;
+template class ConcreteDispatcher<MetalDriver>;
 
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalDriverFactory.h

@@ -24,7 +24,7 @@ class Driver;
 
 class MetalDriverFactory {
 public:
-    static Driver* create(backend::MetalPlatform* platform);
+    static Driver* create(MetalPlatform* platform);
 };
 
 } // namespace backend

filament/backend/src/metal/MetalEnums.h

@@ -27,7 +27,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 struct MetalContext;
 
@@ -405,7 +404,6 @@ inline MTLTextureSwizzleChannels getSwizzleChannels(TextureSwizzle r, TextureSwi
             getSwizzle(a));
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalEnums.mm

@@ -20,7 +20,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 MTLPixelFormat getMetalFormat(MetalContext* context, TextureFormat format) noexcept {
     switch (format) {
@@ -207,6 +206,5 @@ MTLPixelFormat getMetalFormat(MetalContext* context, TextureFormat format) noexc
     return MTLPixelFormatInvalid;
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalExternalImage.h

@@ -24,7 +24,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 struct MetalContext;
 
@@ -129,7 +128,6 @@ private:
     } mSwizzle;
 };
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalExternalImage.mm

@@ -32,7 +32,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 static const auto cvBufferDeleter = [](const void* buffer) {
     CVBufferRelease((CVMetalTextureRef) buffer);
@@ -300,6 +299,5 @@ id<MTLCommandBuffer> MetalExternalImage::encodeColorConversionPass(id<MTLTexture
     return commandBuffer;
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalHandles.h

@@ -40,7 +40,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 class MetalSwapChain : public HwSwapChain {
 public:
@@ -357,7 +356,6 @@ struct MetalTimerQuery : public HwTimerQuery {
     std::shared_ptr<Status> status;
 };
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalHandles.mm

@@ -32,7 +32,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 static inline MTLTextureUsage getMetalTextureUsage(TextureUsage usage) {
     NSUInteger u = 0;
@@ -68,9 +67,8 @@ MetalSwapChain::MetalSwapChain(MetalContext& context, CAMetalLayer* nativeWindow
     }
 
     // Needed so we can use the SwapChain as a blit source.
-    if (flags & SwapChain::CONFIG_READABLE) {
-        nativeWindow.framebufferOnly = NO;
-    }
+    // Also needed for rendering directly into the SwapChain during refraction.
+    nativeWindow.framebufferOnly = NO;
 
     layer.device = context.device;
 }
@@ -81,7 +79,7 @@ MetalSwapChain::MetalSwapChain(MetalContext& context, int32_t width, int32_t hei
 
 MetalSwapChain::MetalSwapChain(MetalContext& context, CVPixelBufferRef pixelBuffer, uint64_t flags)
         : context(context), externalImage(context), type(SwapChainType::CVPIXELBUFFERREF) {
-    assert_invariant(flags & backend::SWAP_CHAIN_CONFIG_APPLE_CVPIXELBUFFER);
+    assert_invariant(flags & SWAP_CHAIN_CONFIG_APPLE_CVPIXELBUFFER);
     MetalExternalImage::assertWritableImage(pixelBuffer);
     externalImage.set(pixelBuffer);
     assert_invariant(externalImage.isValid());
@@ -224,7 +222,7 @@ void MetalSwapChain::scheduleFrameScheduledCallback() {
     }
 
     assert_invariant(drawable);
-    backend::FrameScheduledCallback callback = frameScheduledCallback;
+    FrameScheduledCallback callback = frameScheduledCallback;
     // This block strongly captures drawable to keep it alive until the handler executes.
     // We cannot simply reference this->drawable inside the block because the block would then only
     // capture the _this_ pointer (MetalSwapChain*) instead of the drawable.
@@ -245,12 +243,12 @@ void MetalSwapChain::scheduleFrameCompletedCallback() {
         return;
     }
 
-    backend::FrameCompletedCallback callback = frameCompletedCallback;
+    FrameCompletedCallback callback = frameCompletedCallback;
     void* userData = frameCompletedUserData;
     [getPendingCommandBuffer(&context) addCompletedHandler:^(id<MTLCommandBuffer> cb) {
         struct CallbackData {
             void* userData;
-            backend::FrameCompletedCallback callback;
+            FrameCompletedCallback callback;
         };
         CallbackData* data = new CallbackData();
         data->userData = userData;
@@ -1024,6 +1022,5 @@ FenceStatus MetalFence::wait(uint64_t timeoutNs) {
     return FenceStatus::ERROR;
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalResourceTracker.cpp

@@ -20,7 +20,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 bool MetalResourceTracker::trackResource(CommandBuffer buffer, Resource resource,
         ResourceDeleter deleter) {
@@ -53,6 +52,5 @@ void MetalResourceTracker::clearResources(CommandBuffer buffer) {
     mResources.erase(found);
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalResourceTracker.h

@@ -25,7 +25,6 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 /**
  * MetalResourceTracker is a simple utility that maps individual command buffers to a set of
@@ -76,7 +75,6 @@ private:
     std::mutex mMutex;
 };
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalState.h

@@ -31,24 +31,21 @@
 namespace filament {
 namespace backend {
 
-inline bool operator==(const backend::SamplerParams& lhs, const backend::SamplerParams& rhs) {
+inline bool operator==(const SamplerParams& lhs, const SamplerParams& rhs) {
     return lhs.u == rhs.u;
 }
 
-namespace metal {
-
-static constexpr uint32_t MAX_VERTEX_ATTRIBUTE_COUNT = backend::MAX_VERTEX_ATTRIBUTE_COUNT;
 static constexpr uint32_t SAMPLER_GROUP_COUNT = Program::BINDING_COUNT;
-static constexpr uint32_t SAMPLER_BINDING_COUNT = backend::MAX_SAMPLER_COUNT;
+static constexpr uint32_t SAMPLER_BINDING_COUNT = MAX_SAMPLER_COUNT;
 static constexpr uint32_t VERTEX_BUFFER_START = Program::BINDING_COUNT;
 
 // The "zero" buffer is a small buffer for missing attributes that resides in the vertex slot
 // immediately following any user-provided vertex buffers.
-static constexpr uint32_t ZERO_VERTEX_BUFFER = backend::MAX_VERTEX_BUFFER_COUNT;
+static constexpr uint32_t ZERO_VERTEX_BUFFER = MAX_VERTEX_BUFFER_COUNT;
 
 // The total number of vertex buffer "slots" that the Metal backend can bind.
 // + 1 to account for the zero buffer.
-static constexpr uint32_t VERTEX_BUFFER_COUNT = backend::MAX_VERTEX_BUFFER_COUNT + 1;
+static constexpr uint32_t VERTEX_BUFFER_COUNT = MAX_VERTEX_BUFFER_COUNT + 1;
 
 // Forward declarations necessary here, definitions at end of file.
 inline bool operator==(const MTLViewport& lhs, const MTLViewport& rhs);
@@ -212,7 +209,7 @@ private:
 
 // Pipeline state
 
-struct PipelineState {
+struct MetalPipelineState {
     id<MTLFunction> vertexFunction = nil;                                      // 8 bytes
     id<MTLFunction> fragmentFunction = nil;                                    // 8 bytes
     VertexDescription vertexDescription;                                       // 528 bytes
@@ -223,7 +220,7 @@ struct PipelineState {
     bool colorWrite = true;                                                    // 1 byte
     char padding[7] = { 0 };                                                   // 7 bytes
 
-    bool operator==(const PipelineState& rhs) const noexcept {
+    bool operator==(const MetalPipelineState& rhs) const noexcept {
         return (
                 this->vertexFunction == rhs.vertexFunction &&
                 this->fragmentFunction == rhs.fragmentFunction &&
@@ -237,23 +234,23 @@ struct PipelineState {
         );
     }
 
-    bool operator!=(const PipelineState& rhs) const noexcept {
+    bool operator!=(const MetalPipelineState& rhs) const noexcept {
         return !operator==(rhs);
     }
 };
 
 // This assert checks that the struct is the size we expect without any "hidden" padding bytes
 // inserted by the compiler.
-static_assert(sizeof(PipelineState) == 688, "PipelineState unexpected size.");
+static_assert(sizeof(MetalPipelineState) == 688, "MetalPipelineState unexpected size.");
 
 struct PipelineStateCreator {
-    id<MTLRenderPipelineState> operator()(id<MTLDevice> device, const PipelineState& state)
+    id<MTLRenderPipelineState> operator()(id<MTLDevice> device, const MetalPipelineState& state)
             noexcept;
 };
 
-using PipelineStateTracker = StateTracker<PipelineState>;
+using PipelineStateTracker = StateTracker<MetalPipelineState>;
 
-using PipelineStateCache = StateCache<PipelineState, id<MTLRenderPipelineState>,
+using PipelineStateCache = StateCache<MetalPipelineState, id<MTLRenderPipelineState>,
         PipelineStateCreator>;
 
 // Depth-stencil State
@@ -315,7 +312,7 @@ using UniformBufferStateTracker = StateTracker<UniformBufferState>;
 // Sampler states
 
 struct SamplerState {
-    backend::SamplerParams samplerParams;
+    SamplerParams samplerParams;
     uint32_t minLod = 0;
     uint32_t maxLod = UINT_MAX;
 
@@ -343,7 +340,6 @@ using SamplerStateCache = StateCache<SamplerState, id<MTLSamplerState>, SamplerS
 using CullModeStateTracker = StateTracker<MTLCullMode>;
 using WindingStateTracker = StateTracker<MTLWinding>;
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalState.mm

@@ -20,10 +20,9 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 id<MTLRenderPipelineState> PipelineStateCreator::operator()(id<MTLDevice> device,
-        const PipelineState& state) noexcept {
+        const MetalPipelineState& state) noexcept {
     MTLRenderPipelineDescriptor* descriptor = [MTLRenderPipelineDescriptor new];
 
     // Shader Functions
@@ -105,7 +104,7 @@ id<MTLDepthStencilState> DepthStateCreator::operator()(id<MTLDevice> device,
 
 id<MTLSamplerState> SamplerStateCreator::operator()(id<MTLDevice> device,
         const SamplerState& state) noexcept {
-    backend::SamplerParams params = state.samplerParams;
+    SamplerParams params = state.samplerParams;
     MTLSamplerDescriptor* samplerDescriptor = [MTLSamplerDescriptor new];
     samplerDescriptor.minFilter = getFilter(params.filterMin);
     samplerDescriptor.magFilter = getFilter(params.filterMag);
@@ -133,6 +132,5 @@ id<MTLSamplerState> SamplerStateCreator::operator()(id<MTLDevice> device,
     return [device newSamplerStateWithDescriptor:samplerDescriptor];
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalTimerQuery.h

@@ -23,14 +23,13 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
 struct MetalTimerQuery;
 struct MetalContext;
 
-class TimerQueryInterface {
+class MetalTimerQueryInterface {
 public:
-    virtual ~TimerQueryInterface();
+    virtual ~MetalTimerQueryInterface();
     virtual void beginTimeElapsedQuery(MetalTimerQuery* query) = 0;
     virtual void endTimeElapsedQuery(MetalTimerQuery* query) = 0;
     virtual bool getQueryResult(MetalTimerQuery* query, uint64_t* outElapsedTime) = 0;
@@ -41,9 +40,9 @@ protected:
 
 // Uses MTLSharedEvents to implement timer queries.
 // Only available on >= iOS 12.0.
-class API_AVAILABLE(ios(12.0)) TimerQueryFence : public TimerQueryInterface {
+class API_AVAILABLE(ios(12.0)) MetalTimerQueryFence : public MetalTimerQueryInterface {
 public:
-    explicit TimerQueryFence(MetalContext& context) : mContext(context) {}
+    explicit MetalTimerQueryFence(MetalContext& context) : mContext(context) {}
 
     void beginTimeElapsedQuery(MetalTimerQuery* query) override;
     void endTimeElapsedQuery(MetalTimerQuery* query) override;
@@ -53,14 +52,13 @@ private:
     MetalContext& mContext;
 };
 
-class TimerQueryNoop : public TimerQueryInterface {
+class TimerQueryNoop : public MetalTimerQueryInterface {
 public:
     void beginTimeElapsedQuery(MetalTimerQuery* query) override {}
     void endTimeElapsedQuery(MetalTimerQuery* query) override {}
     bool getQueryResult(MetalTimerQuery* query, uint64_t* outElapsedTime) override;
 };
 
-} // namespace metal
 } // namespace backend
 } // namespace filament
 

filament/backend/src/metal/MetalTimerQuery.mm

@@ -20,11 +20,10 @@
 
 namespace filament {
 namespace backend {
-namespace metal {
 
-TimerQueryInterface::~TimerQueryInterface() = default;
+MetalTimerQueryInterface::~MetalTimerQueryInterface() = default;
 
-void TimerQueryFence::beginTimeElapsedQuery(MetalTimerQuery* query) {
+void MetalTimerQueryFence::beginTimeElapsedQuery(MetalTimerQuery* query) {
     auto* fence = new MetalFence(mContext);
     fence->encode();
     query->status->elapsed = 0;
@@ -41,7 +40,7 @@ void TimerQueryFence::beginTimeElapsedQuery(MetalTimerQuery* query) {
     });
 }
 
-void TimerQueryFence::endTimeElapsedQuery(MetalTimerQuery* query) {
+void MetalTimerQueryFence::endTimeElapsedQuery(MetalTimerQuery* query) {
     auto* fence = new MetalFence(mContext);
     fence->encode();
 
@@ -57,7 +56,7 @@ void TimerQueryFence::endTimeElapsedQuery(MetalTimerQuery* query) {
     });
 }
 
-bool TimerQueryFence::getQueryResult(MetalTimerQuery* query, uint64_t* outElapsedTime) {
+bool MetalTimerQueryFence::getQueryResult(MetalTimerQuery* query, uint64_t* outElapsedTime) {
     if (!query->status->available.load()) {
         return false;
     }
@@ -71,6 +70,5 @@ bool TimerQueryNoop::getQueryResult(MetalTimerQuery* query, uint64_t* outElapsed
     return false;
 }
 
-} // namespace metal
 } // namespace backend
 } // namespace filament

filament/backend/src/metal/MetalUtils.h

@@ -19,7 +19,7 @@
 
 #include <Metal/Metal.h>
 
-namespace filament::backend::metal {
+namespace filament::backend {
 
 /**
  * Creates a texture view of the passed-in texture with the given swizzle. If swizzle is the default
@@ -29,6 +29,19 @@ API_AVAILABLE(ios(13.0))
 id<MTLTexture> createTextureViewWithSwizzle(id<MTLTexture> texture,
         MTLTextureSwizzleChannels swizzle);
 
-} // namespace filament::backend::metal
+/**
+ * Creates a texture view of the passed-in texture with the given layer.
+ *
+ * The returned MTLTexture will have a type of MTLTextureType2D.
+ * The following MTLTextureTypes are supported:
+ *  - MTLTextureType2D (this is a no-op)
+ *  - MTLTextureType2DArray
+ *  - MTLTextureTypeCube
+ *
+ * All other MTLTextureTypes are unsupported.
+ */
+id<MTLTexture> createTextureViewWithSingleSlice(id<MTLTexture> texture, NSUInteger slice);
+
+} // namespace filament::backend
 
 #endif //TNT_FILAMENT_DRIVER_METALUTILS_H

filament/backend/src/metal/MetalUtils.mm

@@ -16,7 +16,7 @@
 
 #include "MetalUtils.h"
 
-namespace filament::backend::metal {
+namespace filament::backend {
 
 id<MTLTexture> createTextureViewWithSwizzle(id<MTLTexture> texture,
         MTLTextureSwizzleChannels swizzle) {
@@ -37,4 +37,15 @@ id<MTLTexture> createTextureViewWithSwizzle(id<MTLTexture> texture,
                                           swizzle:swizzle];
 }
 
+id<MTLTexture> createTextureViewWithSingleSlice(id<MTLTexture> texture, NSUInteger slice) {
+    if (texture.textureType == MTLTextureType2D) {
+        return texture;
+    }
+    NSUInteger mips = texture.mipmapLevelCount;
+    return [texture newTextureViewWithPixelFormat:texture.pixelFormat
+                                      textureType:MTLTextureType2D
+                                           levels:NSMakeRange(0, mips)
+                                           slices:NSMakeRange(slice, 1)];
 }
+
+} // namespace filament::backend

filament/backend/src/noop/NoopDriver.cpp

@@ -17,9 +17,7 @@
 #include "noop/NoopDriver.h"
 #include "CommandStreamDispatcher.h"
 
-namespace filament {
-
-using namespace backend;
+namespace filament::backend {
 
 Driver* NoopDriver::create() {
     return new NoopDriver();
@@ -30,7 +28,7 @@ NoopDriver::NoopDriver() noexcept : DriverBase(new ConcreteDispatcher<NoopDriver
 
 NoopDriver::~NoopDriver() noexcept = default;
 
-backend::ShaderModel NoopDriver::getShaderModel() const noexcept {
+ShaderModel NoopDriver::getShaderModel() const noexcept {
 #if defined(__ANDROID__) || defined(IOS) || defined(__EMSCRIPTEN__)
     return ShaderModel::GL_ES_30;
 #else
@@ -39,7 +37,7 @@ backend::ShaderModel NoopDriver::getShaderModel() const noexcept {
 }
 
 // explicit instantiation of the Dispatcher
-template class backend::ConcreteDispatcher<NoopDriver>;
+template class ConcreteDispatcher<NoopDriver>;
 
 
 void NoopDriver::terminate() {
@@ -52,12 +50,12 @@ void NoopDriver::beginFrame(int64_t monotonic_clock_ns, uint32_t frameId) {
 }
 
 void NoopDriver::setFrameScheduledCallback(Handle<HwSwapChain> sch,
-        backend::FrameScheduledCallback callback, void* user) {
+        FrameScheduledCallback callback, void* user) {
 
 }
 
 void NoopDriver::setFrameCompletedCallback(Handle<HwSwapChain> sch,
-        backend::FrameCompletedCallback callback, void* user) {
+        FrameCompletedCallback callback, void* user) {
 
 }
 
@@ -118,7 +116,7 @@ Handle<HwStream> NoopDriver::createStreamAcquired() {
 }
 
 void NoopDriver::setAcquiredImage(Handle<HwStream> sh, void* image,
-        backend::CallbackHandler* handler, backend::StreamCallback cb, void* userData) {
+        CallbackHandler* handler, StreamCallback cb, void* userData) {
 }
 
 void NoopDriver::setStreamDimensions(Handle<HwStream> sh, uint32_t width, uint32_t height) {
@@ -148,7 +146,7 @@ bool NoopDriver::isTextureSwizzleSupported() {
     return true;
 }
 
-bool NoopDriver::isTextureFormatMipmappable(backend::TextureFormat format) {
+bool NoopDriver::isTextureFormatMipmappable(TextureFormat format) {
     return true;
 }
 
@@ -181,7 +179,7 @@ math::float2 NoopDriver::getClipSpaceParams() {
 }
 
 uint8_t NoopDriver::getMaxDrawBuffers() {
-    return backend::MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT;
+    return MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT;
 }
 
 void NoopDriver::updateIndexBuffer(Handle<HwIndexBuffer> ibh, BufferDescriptor&& p,
@@ -313,8 +311,8 @@ void NoopDriver::readStreamPixels(Handle<HwStream> sh, uint32_t x, uint32_t y, u
 }
 
 void NoopDriver::blit(TargetBufferFlags buffers,
-        Handle<HwRenderTarget> dst, backend::Viewport dstRect,
-        Handle<HwRenderTarget> src, backend::Viewport srcRect,
+        Handle<HwRenderTarget> dst, Viewport dstRect,
+        Handle<HwRenderTarget> src, Viewport srcRect,
         SamplerMagFilter filter) {
 }
 

filament/backend/src/noop/NoopDriver.h

@@ -14,32 +14,32 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_NOOPDRIVER_H
-#define TNT_FILAMENT_DRIVER_NOOPDRIVER_H
+#ifndef TNT_FILAMENT_BACKEND_NOOPDRIVER_H
+#define TNT_FILAMENT_BACKEND_NOOPDRIVER_H
 
 #include "private/backend/Driver.h"
 #include "DriverBase.h"
 
 #include <utils/compiler.h>
 
-namespace filament {
+namespace filament::backend {
 
-class NoopDriver final : public backend::DriverBase {
+class NoopDriver final : public DriverBase {
     NoopDriver() noexcept;
     ~NoopDriver() noexcept override;
 
 public:
-    static backend::Driver* create();
+    static Driver* create();
 
 private:
-    backend::ShaderModel getShaderModel() const noexcept final;
+    ShaderModel getShaderModel() const noexcept final;
 
     /*
      * Driver interface
      */
 
     template<typename T>
-    friend class backend::ConcreteDispatcher;
+    friend class ConcreteDispatcher;
 
 #define DECL_DRIVER_API(methodName, paramsDecl, params) \
     UTILS_ALWAYS_INLINE inline void methodName(paramsDecl);
@@ -57,4 +57,4 @@ private:
 
 } // namespace filament
 
-#endif // TNT_FILAMENT_DRIVER_NOOPDRIVER_H
+#endif // TNT_FILAMENT_BACKEND_NOOPDRIVER_H

filament/backend/src/noop/PlatformNoop.cpp

@@ -18,9 +18,9 @@
 
 #include "noop/NoopDriver.h"
 
-namespace filament {
+namespace filament::backend {
 
-backend::Driver* PlatformNoop::createDriver(void* const sharedGLContext) noexcept {
+Driver* PlatformNoop::createDriver(void* const sharedGLContext) noexcept {
     return NoopDriver::create();
 }
 

filament/backend/src/noop/PlatformNoop.h

@@ -14,15 +14,15 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_NOOP_PLATFORM_NOOP_H
-#define TNT_FILAMENT_DRIVER_NOOP_PLATFORM_NOOP_H
+#ifndef TNT_FILAMENT_BACKEND_NOOP_PLATFORM_NOOP_H
+#define TNT_FILAMENT_BACKEND_NOOP_PLATFORM_NOOP_H
 
 #include <backend/DriverEnums.h>
 #include <backend/Platform.h>
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformNoop final : public backend::DefaultPlatform {
+class PlatformNoop final : public DefaultPlatform {
 public:
 
     int getOSVersion() const noexcept final { return 0; }
@@ -31,9 +31,9 @@ public:
 
 protected:
 
-    backend::Driver* createDriver(void* sharedContext) noexcept override;
+    Driver* createDriver(void* sharedContext) noexcept override;
 };
 
 } // namespace filament
 
-#endif // TNT_FILAMENT_DRIVER_NOOP_PLATFORM_NOOP_H
+#endif // TNT_FILAMENT_BACKEND_NOOP_PLATFORM_NOOP_H

filament/backend/src/opengl/GLUtils.cpp

@@ -20,7 +20,7 @@
 
 #include "private/backend/Driver.h"
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 using namespace utils;
@@ -122,4 +122,4 @@ void assertFramebufferStatus(io::ostream& out, GLenum target, const char* functi
 }
 
 } // namespace GLUtils
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/GLUtils.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_GLUTILS_H
-#define TNT_FILAMENT_DRIVER_GLUTILS_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_GLUTILS_H
+#define TNT_FILAMENT_BACKEND_OPENGL_GLUTILS_H
 
 #include <utils/compiler.h>
 #include <utils/Log.h>
@@ -29,7 +29,7 @@
 
 #include "gl_headers.h"
 
-namespace filament {
+namespace filament::backend {
 namespace GLUtils {
 
 const char* getGLError(GLenum error) noexcept;
@@ -51,8 +51,8 @@ void assertFramebufferStatus(utils::io::ostream& out, GLenum target, const char*
 #   define CHECK_GL_FRAMEBUFFER_STATUS(out, target) { GLUtils::checkFramebufferStatus(out, target, __PRETTY_FUNCTION__, __LINE__); }
 #endif
 
-constexpr inline GLuint getComponentCount(backend::ElementType type) noexcept {
-    using ElementType = backend::ElementType;
+constexpr inline GLuint getComponentCount(ElementType type) noexcept {
+    using ElementType = ElementType;
     switch (type) {
         case ElementType::BYTE:
         case ElementType::UBYTE:
@@ -91,35 +91,35 @@ constexpr inline GLuint getComponentCount(backend::ElementType type) noexcept {
 // Our enums to GLenum conversions
 // ------------------------------------------------------------------------------------------------
 
-constexpr inline GLbitfield getAttachmentBitfield(backend::TargetBufferFlags flags) noexcept {
+constexpr inline GLbitfield getAttachmentBitfield(TargetBufferFlags flags) noexcept {
     GLbitfield mask = 0;
-    if (any(flags & backend::TargetBufferFlags::COLOR_ALL)) {
+    if (any(flags & TargetBufferFlags::COLOR_ALL)) {
         mask |= (GLbitfield)GL_COLOR_BUFFER_BIT;
     }
-    if (any(flags & backend::TargetBufferFlags::DEPTH)) {
+    if (any(flags & TargetBufferFlags::DEPTH)) {
         mask |= (GLbitfield)GL_DEPTH_BUFFER_BIT;
     }
-    if (any(flags & backend::TargetBufferFlags::STENCIL)) {
+    if (any(flags & TargetBufferFlags::STENCIL)) {
         mask |= (GLbitfield)GL_STENCIL_BUFFER_BIT;
     }
     return mask;
 }
 
-constexpr inline GLenum getBufferUsage(backend::BufferUsage usage) noexcept {
+constexpr inline GLenum getBufferUsage(BufferUsage usage) noexcept {
     switch (usage) {
-        case backend::BufferUsage::STATIC:
+        case BufferUsage::STATIC:
             return GL_STATIC_DRAW;
-        case backend::BufferUsage::DYNAMIC:
-        case backend::BufferUsage::STREAM:
+        case BufferUsage::DYNAMIC:
+        case BufferUsage::STREAM:
             return GL_DYNAMIC_DRAW;
     }
 }
 
-constexpr inline GLenum getBufferBindingType(backend::BufferObjectBinding bindingType) noexcept {
+constexpr inline GLenum getBufferBindingType(BufferObjectBinding bindingType) noexcept {
     switch (bindingType) {
-        case backend::BufferObjectBinding::VERTEX:
+        case BufferObjectBinding::VERTEX:
             return GL_ARRAY_BUFFER;
-        case backend::BufferObjectBinding::UNIFORM:
+        case BufferObjectBinding::UNIFORM:
             return GL_UNIFORM_BUFFER;
     }
 }
@@ -128,8 +128,8 @@ constexpr inline GLboolean getNormalization(bool normalized) noexcept {
     return GLboolean(normalized ? GL_TRUE : GL_FALSE);
 }
 
-constexpr inline GLenum getComponentType(backend::ElementType type) noexcept {
-    using ElementType = backend::ElementType;
+constexpr inline GLenum getComponentType(ElementType type) noexcept {
+    using ElementType = ElementType;
     switch (type) {
         case ElementType::BYTE:
         case ElementType::BYTE2:
@@ -173,8 +173,8 @@ constexpr inline GLenum getCubemapTarget(uint16_t layer) noexcept {
     return GL_TEXTURE_CUBE_MAP_POSITIVE_X + layer;
 }
 
-constexpr inline GLenum getWrapMode(backend::SamplerWrapMode mode) noexcept {
-    using SamplerWrapMode = backend::SamplerWrapMode;
+constexpr inline GLenum getWrapMode(SamplerWrapMode mode) noexcept {
+    using SamplerWrapMode = SamplerWrapMode;
     switch (mode) {
         case SamplerWrapMode::REPEAT:
             return GL_REPEAT;
@@ -185,8 +185,8 @@ constexpr inline GLenum getWrapMode(backend::SamplerWrapMode mode) noexcept {
     }
 }
 
-constexpr inline GLenum getTextureFilter(backend::SamplerMinFilter filter) noexcept {
-    using SamplerMinFilter = backend::SamplerMinFilter;
+constexpr inline GLenum getTextureFilter(SamplerMinFilter filter) noexcept {
+    using SamplerMinFilter = SamplerMinFilter;
     switch (filter) {
         case SamplerMinFilter::NEAREST:
         case SamplerMinFilter::LINEAR:
@@ -200,13 +200,13 @@ constexpr inline GLenum getTextureFilter(backend::SamplerMinFilter filter) noexc
     }
 }
 
-constexpr inline GLenum getTextureFilter(backend::SamplerMagFilter filter) noexcept {
+constexpr inline GLenum getTextureFilter(SamplerMagFilter filter) noexcept {
     return GL_NEAREST + GLenum(filter);
 }
 
 
-constexpr inline GLenum getBlendEquationMode(backend::BlendEquation mode) noexcept {
-    using BlendEquation = backend::BlendEquation;
+constexpr inline GLenum getBlendEquationMode(BlendEquation mode) noexcept {
+    using BlendEquation = BlendEquation;
     switch (mode) {
         case BlendEquation::ADD:               return GL_FUNC_ADD;
         case BlendEquation::SUBTRACT:          return GL_FUNC_SUBTRACT;
@@ -216,8 +216,8 @@ constexpr inline GLenum getBlendEquationMode(backend::BlendEquation mode) noexce
     }
 }
 
-constexpr inline GLenum getBlendFunctionMode(backend::BlendFunction mode) noexcept {
-    using BlendFunction = backend::BlendFunction;
+constexpr inline GLenum getBlendFunctionMode(BlendFunction mode) noexcept {
+    using BlendFunction = BlendFunction;
     switch (mode) {
         case BlendFunction::ZERO:                  return GL_ZERO;
         case BlendFunction::ONE:                   return GL_ONE;
@@ -233,13 +233,13 @@ constexpr inline GLenum getBlendFunctionMode(backend::BlendFunction mode) noexce
     }
 }
 
-constexpr inline GLenum getTextureCompareMode(backend::SamplerCompareMode mode) noexcept {
-    return mode == backend::SamplerCompareMode::NONE ?
+constexpr inline GLenum getTextureCompareMode(SamplerCompareMode mode) noexcept {
+    return mode == SamplerCompareMode::NONE ?
            GL_NONE : GL_COMPARE_REF_TO_TEXTURE;
 }
 
-constexpr inline GLenum getTextureCompareFunc(backend::SamplerCompareFunc func) noexcept {
-    using SamplerCompareFunc = backend::SamplerCompareFunc;
+constexpr inline GLenum getTextureCompareFunc(SamplerCompareFunc func) noexcept {
+    using SamplerCompareFunc = SamplerCompareFunc;
     switch (func) {
         case SamplerCompareFunc::LE:    return GL_LEQUAL;
         case SamplerCompareFunc::GE:    return GL_GEQUAL;
@@ -252,12 +252,12 @@ constexpr inline GLenum getTextureCompareFunc(backend::SamplerCompareFunc func)
     }
 }
 
-constexpr inline GLenum getDepthFunc(backend::SamplerCompareFunc func) noexcept {
+constexpr inline GLenum getDepthFunc(SamplerCompareFunc func) noexcept {
     return getTextureCompareFunc(func);
 }
 
-constexpr inline GLenum getFormat(backend::PixelDataFormat format) noexcept {
-    using PixelDataFormat = backend::PixelDataFormat;
+constexpr inline GLenum getFormat(PixelDataFormat format) noexcept {
+    using PixelDataFormat = PixelDataFormat;
     switch (format) {
         case PixelDataFormat::R:                return GL_RED;
         case PixelDataFormat::R_INTEGER:        return GL_RED_INTEGER;
@@ -274,8 +274,8 @@ constexpr inline GLenum getFormat(backend::PixelDataFormat format) noexcept {
     }
 }
 
-constexpr inline GLenum getType(backend::PixelDataType type) noexcept {
-    using PixelDataType = backend::PixelDataType;
+constexpr inline GLenum getType(PixelDataType type) noexcept {
+    using PixelDataType = PixelDataType;
     switch (type) {
         case PixelDataType::UBYTE:                return GL_UNSIGNED_BYTE;
         case PixelDataType::BYTE:                 return GL_BYTE;
@@ -292,8 +292,8 @@ constexpr inline GLenum getType(backend::PixelDataType type) noexcept {
     }
 }
 
-constexpr inline GLenum getSwizzleChannel(backend::TextureSwizzle c) noexcept {
-    using TextureSwizzle = backend::TextureSwizzle;
+constexpr inline GLenum getSwizzleChannel(TextureSwizzle c) noexcept {
+    using TextureSwizzle = TextureSwizzle;
     switch (c) {
         case TextureSwizzle::SUBSTITUTE_ZERO:
             return GL_ZERO;
@@ -313,8 +313,8 @@ constexpr inline GLenum getSwizzleChannel(backend::TextureSwizzle c) noexcept {
 // clang looses it on this one, and generates a huge jump table when
 // inlined. So we don't  mark it as inline (only constexpr) which solves the problem,
 // strangely, when not inlined, clang simply generates an array lookup.
-constexpr /* inline */ GLenum getInternalFormat(backend::TextureFormat format) noexcept {
-    using TextureFormat = backend::TextureFormat;
+constexpr /* inline */ GLenum getInternalFormat(TextureFormat format) noexcept {
+    using TextureFormat = TextureFormat;
     switch (format) {
         // 8-bits per element
         case TextureFormat::R8:                return GL_R8;
@@ -530,6 +530,6 @@ inline unordered_string_set split(const char* spacedList) {
 }
 
 } // namespace GLUtils
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_GLUTILS_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_GLUTILS_H

filament/backend/src/opengl/NullGLES.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_NULLGLES_H
-#define TNT_FILAMENT_DRIVER_NULLGLES_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_NULLGLES_H
+#define TNT_FILAMENT_BACKEND_OPENGL_NULLGLES_H
 
 /*
  * This is used for debugging (stubbing out GLES calls)
@@ -27,7 +27,7 @@
  *
  */
 
-namespace filament {
+namespace filament::backend {
 namespace nullgles {
 
 inline void glScissor(GLint, GLint, GLsizei, GLsizei) { }
@@ -81,6 +81,6 @@ inline GLenum glGetError() { return GL_NO_ERROR; }
 // turn GLES calls defined above into no-ops
 //using namespace nullgles;
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_NULLGLES_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_NULLGLES_H

filament/backend/src/opengl/OpenGLBlitter.cpp

@@ -27,7 +27,7 @@
 using namespace filament::math;
 using namespace utils;
 
-namespace filament {
+namespace filament::backend {
 
 static const char s_vertexES[] = R"SHADER(#version 300 es
 in vec4 pos;
@@ -212,4 +212,4 @@ void OpenGLBlitter::State::restore() noexcept {
     CHECK_GL_ERROR(utils::slog.e)
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/OpenGLBlitter.h

@@ -14,13 +14,13 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGLBLITTER_H
-#define TNT_FILAMENT_DRIVER_OPENGLBLITTER_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGLBLITTER_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGLBLITTER_H
 
 #include <utils/compiler.h>
 #include "gl_headers.h"
 
-namespace filament {
+namespace filament::backend {
 
 class OpenGLContext;
 
@@ -62,6 +62,6 @@ private:
     GLuint mFBO{};
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGLBLITTER_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGLBLITTER_H

filament/backend/src/opengl/OpenGLContext.cpp

@@ -22,7 +22,7 @@
 
 using namespace utils;
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 

filament/backend/src/opengl/OpenGLContext.h

@@ -30,11 +30,11 @@
 #include <set>
 #include <utility>
 
-namespace filament {
+namespace filament::backend {
 
 class OpenGLContext {
 public:
-    static constexpr const size_t MAX_TEXTURE_UNIT_COUNT = backend::MAX_SAMPLER_COUNT;
+    static constexpr const size_t MAX_TEXTURE_UNIT_COUNT = MAX_SAMPLER_COUNT;
     static constexpr const size_t MAX_BUFFER_BINDINGS = 32;
     typedef math::details::TVec4<GLint> vec4gli;
     typedef math::details::TVec2<GLclampf> vec2glf;
@@ -51,7 +51,7 @@ public:
         // 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.
-        backend::Handle<backend::HwVertexBuffer> vertexBufferWithObjects = {};
+        Handle<HwVertexBuffer> vertexBufferWithObjects = {};
 
         // If this version number does not match vertexBufferWithObjects->bufferObjectsVersion,
         // then the VAO needs to be updated.
@@ -70,7 +70,7 @@ public:
     constexpr        inline size_t getIndexForCap(GLenum cap) noexcept;
     constexpr static inline size_t getIndexForBufferTarget(GLenum target) noexcept;
 
-    backend::ShaderModel getShaderModel() const noexcept { return mShaderModel; }
+    ShaderModel getShaderModel() const noexcept { return mShaderModel; }
 
 
     inline void useProgram(GLuint program) noexcept;
@@ -256,7 +256,7 @@ public:
     void resetProgram() noexcept { state.program.use = 0; }
 
 private:
-    backend::ShaderModel mShaderModel;
+    ShaderModel mShaderModel;
 
     // Try to keep the State structure sorted by data-access patterns
     struct State {

filament/backend/src/opengl/OpenGLDriver.cpp

@@ -23,7 +23,7 @@
 #include "OpenGLBlitter.h"
 #include "OpenGLDriverFactory.h"
 #include "OpenGLProgram.h"
-#include "TimerQuery.h"
+#include "OpenGLTimerQuery.h"
 #include "OpenGLContext.h"
 
 #include <utils/compiler.h>
@@ -61,17 +61,13 @@
 using namespace filament::math;
 using namespace utils;
 
-namespace filament {
-namespace backend {
+namespace filament::backend {
 
 Driver* OpenGLDriverFactory::create(
         OpenGLPlatform* const platform, void* const sharedGLContext) noexcept {
     return OpenGLDriver::create(platform, sharedGLContext);
 }
 
-} // namespace backend
-
-using namespace backend;
 using namespace GLUtils;
 
 // ------------------------------------------------------------------------------------------------
@@ -92,12 +88,12 @@ Driver* OpenGLDriver::create(
     //    GLBufferObject            :  24       many
     //    GLSync                    :  24       few
     //    GLTimerQuery              :  32       few
+    //    OpenGLProgram             :  32       moderate
     //    GLRenderPrimitive         :  48       many
-    //    OpenGLProgram             :  48       moderate
     // -- less than or equal 64 bytes
     //    GLTexture                 :  72       moderate
     //    GLRenderTarget            : 112       few
-    //    GLStream                  : 168       few
+    //    GLStream                  : 184       few
     //    GLVertexBuffer            : 200       moderate
     // -- less than or equal to 208 bytes
 
@@ -151,7 +147,8 @@ Driver* OpenGLDriver::create(
 
 OpenGLDriver::DebugMarker::DebugMarker(OpenGLDriver& driver, const char* string) noexcept
         : driver(driver) {
-    const char* const begin = string + sizeof("virtual void filament::OpenGLDriver::") - 1;
+    // FIXME: this is not safe nor portable
+    const char* const begin = string + sizeof("virtual void filament::backend::OpenGLDriver::") - 1;
     const char* const end = strchr(begin, '(');
     driver.pushGroupMarker(begin, end - begin);
 }
@@ -188,14 +185,14 @@ OpenGLDriver::OpenGLDriver(OpenGLPlatform* platform) noexcept
         // timer queries are available
         if (mContext.bugs.dont_use_timer_query && mPlatform.canCreateFence()) {
             // however, they don't work well, revert to using fences if we can.
-            mTimerQueryImpl = new TimerQueryFence(mPlatform);
+            mTimerQueryImpl = new OpenGLTimerQueryFence(mPlatform);
         } else {
             mTimerQueryImpl = new TimerQueryNative(mContext);
         }
         mFrameTimeSupported = true;
     } else if (mPlatform.canCreateFence()) {
         // no timer queries, but we can use fences
-        mTimerQueryImpl = new TimerQueryFence(mPlatform);
+        mTimerQueryImpl = new OpenGLTimerQueryFence(mPlatform);
         mFrameTimeSupported = true;
     } else {
         // no queries, no fences -- that's a problem
@@ -244,7 +241,7 @@ ShaderModel OpenGLDriver::getShaderModel() const noexcept {
 // Change and track GL state
 // ------------------------------------------------------------------------------------------------
 
-void OpenGLDriver::bindSampler(GLuint unit, backend::SamplerParams params) noexcept {
+void OpenGLDriver::bindSampler(GLuint unit, SamplerParams params) noexcept {
     mContext.bindSampler(unit, getSampler(params));
 }
 
@@ -254,9 +251,8 @@ void OpenGLDriver::bindTexture(GLuint unit, GLTexture const* t) noexcept {
 }
 
 void OpenGLDriver::useProgram(OpenGLProgram* p) noexcept {
-    mContext.useProgram(p->gl.program);
     // set-up textures and samplers in the proper TMUs (as specified in setSamplers)
-    p->use(this);
+    p->use(this, mContext);
 }
 
 
@@ -450,7 +446,7 @@ void OpenGLDriver::createRenderPrimitiveR(Handle<HwRenderPrimitive> rph, int) {
 void OpenGLDriver::createProgramR(Handle<HwProgram> ph, Program&& program) {
     DEBUG_MARKER()
 
-    construct<OpenGLProgram>(ph, this, program);
+    construct<OpenGLProgram>(ph, *this, std::move(program));
     CHECK_GL_ERROR(utils::slog.e)
 }
 
@@ -714,7 +710,7 @@ void OpenGLDriver::updateVertexArrayObject(GLRenderPrimitive* rp, GLVertexBuffer
     }
 }
 
-void OpenGLDriver::framebufferTexture(backend::TargetBufferInfo const& binfo,
+void OpenGLDriver::framebufferTexture(TargetBufferInfo const& binfo,
         GLRenderTarget const* rt, GLenum attachment) noexcept {
 
 #if !defined(NDEBUG)
@@ -1010,7 +1006,7 @@ void OpenGLDriver::createRenderTargetR(Handle<HwRenderTarget> rth,
         uint32_t width,
         uint32_t height,
         uint8_t samples,
-        backend::MRT color,
+        MRT color,
         TargetBufferInfo depth,
         TargetBufferInfo stencil) {
     DEBUG_MARKER()
@@ -1216,6 +1212,7 @@ void OpenGLDriver::destroyProgram(Handle<HwProgram> ph) {
     DEBUG_MARKER()
     if (ph) {
         OpenGLProgram* p = handle_cast<OpenGLProgram*>(ph);
+        cancelRunAtNextPassOp(p);
         destruct(ph, p);
     }
 }
@@ -1360,7 +1357,7 @@ Handle<HwStream> OpenGLDriver::createStreamAcquired() {
 // called only once per frame. If the user pushes images to the same stream multiple times in a
 // single frame, we emit a warning and honor only the final image, but still invoke all callbacks.
 void OpenGLDriver::setAcquiredImage(Handle<HwStream> sh, void* hwbuffer,
-        backend::CallbackHandler* handler, backend::StreamCallback cb, void* userData) {
+        CallbackHandler* handler, StreamCallback cb, void* userData) {
     GLStream* glstream = handle_cast<GLStream*>(sh);
     if (glstream->user_thread.pending.image) {
         scheduleRelease(glstream->user_thread.pending);
@@ -1684,7 +1681,7 @@ void OpenGLDriver::updateBufferObject(
     CHECK_GL_ERROR(utils::slog.e)
 }
 
-void OpenGLDriver::updateBuffer(GLBufferObject* buffer, backend::BufferDescriptor const& p,
+void OpenGLDriver::updateBuffer(GLBufferObject* buffer, BufferDescriptor const& p,
         uint32_t byteOffset, uint32_t alignment) noexcept {
     assert_invariant(buffer->byteCount >= p.size);
     assert_invariant(buffer->gl.id);
@@ -2223,6 +2220,9 @@ SyncStatus OpenGLDriver::getSyncStatus(Handle<HwSync> sh) {
 void OpenGLDriver::beginRenderPass(Handle<HwRenderTarget> rth,
         const RenderPassParams& params) {
     DEBUG_MARKER()
+
+    executeRenderPassOps();
+
     auto& gl = mContext;
 
     mRenderPassTarget = rth;
@@ -2345,7 +2345,7 @@ void OpenGLDriver::nextSubpass(int) {}
 
 
 void OpenGLDriver::resolvePass(ResolveAction action, GLRenderTarget const* rt,
-        backend::TargetBufferFlags discardFlags) noexcept {
+        TargetBufferFlags discardFlags) noexcept {
     assert_invariant(rt->gl.fbo_read);
     auto& gl = mContext;
     const TargetBufferFlags resolve = rt->gl.resolve & ~discardFlags;
@@ -2928,6 +2928,25 @@ void OpenGLDriver::executeEveryNowAndThenOps() noexcept {
     }
 }
 
+void OpenGLDriver::runAtNextRenderPass(void* token, std::function<void()> fn) noexcept {
+    assert_invariant(mRunAtNextRenderPassOps.find(token) == mRunAtNextRenderPassOps.end());
+    mRunAtNextRenderPassOps[token] = std::move(fn);
+}
+
+void OpenGLDriver::cancelRunAtNextPassOp(void* token) noexcept {
+    mRunAtNextRenderPassOps.erase(token);
+}
+
+void OpenGLDriver::executeRenderPassOps() noexcept {
+    auto& ops = mRunAtNextRenderPassOps;
+    if (!ops.empty()) {
+        for (auto& item: ops) {
+            item.second();
+        }
+        ops.clear();
+    }
+}
+
 // ------------------------------------------------------------------------------------------------
 // Rendering ops
 // ------------------------------------------------------------------------------------------------
@@ -2956,12 +2975,12 @@ void OpenGLDriver::beginFrame(int64_t monotonic_clock_ns, uint32_t frameId) {
 }
 
 void OpenGLDriver::setFrameScheduledCallback(Handle<HwSwapChain> sch,
-        backend::FrameScheduledCallback callback, void* user) {
+        FrameScheduledCallback callback, void* user) {
 
 }
 
 void OpenGLDriver::setFrameCompletedCallback(Handle<HwSwapChain> sch,
-        backend::FrameCompletedCallback callback, void* user) {
+        FrameCompletedCallback callback, void* user) {
 
 }
 
@@ -3205,6 +3224,6 @@ void OpenGLDriver::draw(PipelineState state, Handle<HwRenderPrimitive> rph, uint
 }
 
 // explicit instantiation of the Dispatcher
-template class backend::ConcreteDispatcher<OpenGLDriver>;
+template class ConcreteDispatcher<OpenGLDriver>;
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/OpenGLDriver.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGLDRIVER_H
-#define TNT_FILAMENT_DRIVER_OPENGLDRIVER_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGLDRIVER_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGLDRIVER_H
 
 #include "private/backend/Driver.h"
 #include "DriverBase.h"
@@ -39,24 +39,22 @@
 #    define FILAMENT_OPENGL_HANDLE_ARENA_SIZE_IN_MB 4
 #endif
 
-namespace filament {
+namespace filament::backend {
 
-namespace backend {
 class OpenGLPlatform;
 class PixelBufferDescriptor;
 struct TargetBufferInfo;
-} // namespace backend
 
 class OpenGLProgram;
 class OpenGLBlitter;
-class TimerQueryInterface;
+class OpenGLTimerQueryInterface;
 
-class OpenGLDriver final : public backend::DriverBase {
-    inline explicit OpenGLDriver(backend::OpenGLPlatform* platform) noexcept;
+class OpenGLDriver final : public DriverBase {
+    inline explicit OpenGLDriver(OpenGLPlatform* platform) noexcept;
     ~OpenGLDriver() noexcept final;
 
 public:
-    static backend::Driver* create(backend::OpenGLPlatform* platform, void* sharedGLContext) noexcept;
+    static Driver* create(OpenGLPlatform* platform, void* sharedGLContext) noexcept;
 
     class DebugMarker {
         OpenGLDriver& driver;
@@ -67,10 +65,10 @@ public:
 
     // OpenGLDriver specific fields
 
-    struct GLBufferObject : public backend::HwBufferObject {
+    struct GLBufferObject : public HwBufferObject {
         using HwBufferObject::HwBufferObject;
         GLBufferObject(uint32_t size,
-                backend::BufferObjectBinding bindingType, backend::BufferUsage usage) noexcept
+                BufferObjectBinding bindingType, BufferUsage usage) noexcept
                 : HwBufferObject(size), usage(usage) {
             gl.binding = GLUtils::getBufferBindingType(bindingType);
         }
@@ -80,34 +78,34 @@ public:
         } gl;
         uint32_t base = 0;
         uint32_t size = 0;
-        backend::BufferUsage usage = {};
+        BufferUsage usage = {};
     };
 
-    struct GLVertexBuffer : public backend::HwVertexBuffer {
+    struct GLVertexBuffer : public HwVertexBuffer {
         using HwVertexBuffer::HwVertexBuffer;
         struct {
             // 4 * MAX_VERTEX_ATTRIBUTE_COUNT bytes
-            std::array<GLuint, backend::MAX_VERTEX_ATTRIBUTE_COUNT> buffers{};
+            std::array<GLuint, MAX_VERTEX_ATTRIBUTE_COUNT> buffers{};
         } gl;
     };
 
-    struct GLIndexBuffer : public backend::HwIndexBuffer {
+    struct GLIndexBuffer : public HwIndexBuffer {
         using HwIndexBuffer::HwIndexBuffer;
         struct {
             GLuint buffer{};
         } gl;
     };
 
-    struct GLSamplerGroup : public backend::HwSamplerGroup {
+    struct GLSamplerGroup : public HwSamplerGroup {
         using HwSamplerGroup::HwSamplerGroup;
     };
 
-    struct GLRenderPrimitive : public backend::HwRenderPrimitive {
+    struct GLRenderPrimitive : public HwRenderPrimitive {
         using HwRenderPrimitive::HwRenderPrimitive;
         OpenGLContext::RenderPrimitive gl;
     };
 
-    struct GLTexture : public backend::HwTexture {
+    struct GLTexture : public HwTexture {
         using HwTexture::HwTexture;
         struct GL {
             GL() noexcept : imported(false), sidecarSamples(1), reserved(0) {}
@@ -130,7 +128,7 @@ public:
         void* platformPImpl = nullptr;
     };
 
-    struct GLTimerQuery : public backend::HwTimerQuery {
+    struct GLTimerQuery : public HwTimerQuery {
         struct State {
             std::atomic<uint64_t> elapsed{};
             std::atomic_bool available{};
@@ -143,12 +141,12 @@ public:
         std::atomic<uint64_t> elapsed{};
     };
 
-    struct GLStream : public backend::HwStream {
+    struct GLStream : public HwStream {
         static constexpr size_t ROUND_ROBIN_TEXTURE_COUNT = 3;      // 3 maximum
         using HwStream::HwStream;
         struct Info {
             // storage for the read/write textures below
-            backend::Platform::ExternalTexture* ets = nullptr;
+            Platform::ExternalTexture* ets = nullptr;
             GLuint width = 0;
             GLuint height = 0;
         };
@@ -177,27 +175,27 @@ public:
             Info infos[ROUND_ROBIN_TEXTURE_COUNT];      // 48 bytes
             int64_t timestamp = 0;
             uint8_t cur = 0;
-            backend::AcquiredImage acquired;
-            backend::AcquiredImage pending;
+            AcquiredImage acquired;
+            AcquiredImage pending;
         } user_thread;
     };
 
-    struct GLRenderTarget : public backend::HwRenderTarget {
+    struct GLRenderTarget : public HwRenderTarget {
         using HwRenderTarget::HwRenderTarget;
         struct {
             // field ordering to optimize size on 64-bits
-            GLTexture* color[backend::MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT];
+            GLTexture* color[MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT];
             GLTexture* depth;
             GLTexture* stencil;
             GLuint fbo = 0;
             mutable GLuint fbo_read = 0;
-            mutable backend::TargetBufferFlags resolve = backend::TargetBufferFlags::NONE; // attachments in fbo_draw to resolve
+            mutable TargetBufferFlags resolve = TargetBufferFlags::NONE; // attachments in fbo_draw to resolve
             uint8_t samples = 1;
         } gl;
-        backend::TargetBufferFlags targets = {};
+        TargetBufferFlags targets = {};
     };
 
-    struct GLSync : public backend::HwSync {
+    struct GLSync : public HwSync {
         using HwSync::HwSync;
         struct State {
             std::atomic<GLenum> status{ GL_TIMEOUT_EXPIRED };
@@ -216,14 +214,14 @@ private:
 
     OpenGLContext& getContext() noexcept { return mContext; }
 
-    backend::ShaderModel getShaderModel() const noexcept final;
+    ShaderModel getShaderModel() const noexcept final;
 
     /*
      * Driver interface
      */
 
     template<typename T>
-    friend class backend::ConcreteDispatcher;
+    friend class ConcreteDispatcher;
 
 #define DECL_DRIVER_API(methodName, paramsDecl, params) \
     UTILS_ALWAYS_INLINE inline void methodName(paramsDecl);
@@ -240,22 +238,22 @@ private:
     // Memory management...
 
     // See also the explicit template instantiation in HandleAllocator.cpp
-    backend::HandleAllocatorGL mHandleAllocator;
+    HandleAllocatorGL mHandleAllocator;
 
     template<typename D, typename ... ARGS>
-    backend::Handle<D> initHandle(ARGS&& ... args) noexcept {
+    Handle<D> initHandle(ARGS&& ... args) noexcept {
         return mHandleAllocator.allocateAndConstruct<D>(std::forward<ARGS>(args) ...);
     }
 
     template<typename D, typename B, typename ... ARGS>
     typename std::enable_if<std::is_base_of<B, D>::value, D>::type*
-    construct(backend::Handle<B> const& handle, ARGS&& ... args) noexcept {
+    construct(Handle<B> const& handle, ARGS&& ... args) noexcept {
         return mHandleAllocator.destroyAndConstruct<D, B>(handle, std::forward<ARGS>(args) ...);
     }
 
     template<typename B, typename D,
             typename = typename std::enable_if<std::is_base_of<B, D>::value, D>::type>
-    void destruct(backend::Handle<B>& handle, D const* p) noexcept {
+    void destruct(Handle<B>& handle, D const* p) noexcept {
         return mHandleAllocator.deallocate(handle, p);
     }
 
@@ -263,7 +261,7 @@ private:
     typename std::enable_if_t<
             std::is_pointer_v<Dp> &&
             std::is_base_of_v<B, typename std::remove_pointer_t<Dp>>, Dp>
-    handle_cast(backend::Handle<B>& handle) noexcept {
+    handle_cast(Handle<B>& handle) noexcept {
         return mHandleAllocator.handle_cast<Dp, B>(handle);
     }
 
@@ -271,7 +269,7 @@ private:
     inline typename std::enable_if_t<
             std::is_pointer_v<Dp> &&
             std::is_base_of_v<B, typename std::remove_pointer_t<Dp>>, Dp>
-    handle_cast(backend::Handle<B> const& handle) noexcept {
+    handle_cast(Handle<B> const& handle) noexcept {
         return mHandleAllocator.handle_cast<Dp, B>(handle);
     }
 
@@ -287,11 +285,11 @@ private:
 
     void updateVertexArrayObject(GLRenderPrimitive* rp, GLVertexBuffer const* vb);
 
-    void framebufferTexture(backend::TargetBufferInfo const& binfo,
+    void framebufferTexture(TargetBufferInfo const& binfo,
             GLRenderTarget const* rt, GLenum attachment) noexcept;
 
-    void setRasterStateSlow(backend::RasterState rs) noexcept;
-    void setRasterState(backend::RasterState rs) noexcept {
+    void setRasterStateSlow(RasterState rs) noexcept;
+    void setRasterState(RasterState rs) noexcept {
         mRenderPassColorWrite |= rs.colorWrite;
         mRenderPassDepthWrite |= rs.depthWrite;
         if (UTILS_UNLIKELY(rs != mRasterState)) {
@@ -303,13 +301,13 @@ private:
             uint32_t level,
             uint32_t xoffset, uint32_t yoffset, uint32_t zoffset,
             uint32_t width, uint32_t height, uint32_t depth,
-            backend::PixelBufferDescriptor&& data, backend::FaceOffsets const* faceOffsets);
+            PixelBufferDescriptor&& data, FaceOffsets const* faceOffsets);
 
     void setCompressedTextureData(GLTexture* t,
             uint32_t level,
             uint32_t xoffset, uint32_t yoffset, uint32_t zoffset,
             uint32_t width, uint32_t height, uint32_t depth,
-            backend::PixelBufferDescriptor&& data, backend::FaceOffsets const* faceOffsets);
+            PixelBufferDescriptor&& data, FaceOffsets const* faceOffsets);
 
     void renderBufferStorage(GLuint rbo, GLenum internalformat, uint32_t width,
             uint32_t height, uint8_t samples) const noexcept;
@@ -320,16 +318,16 @@ private:
     /* State tracking GL wrappers... */
 
            void bindTexture(GLuint unit, GLTexture const* t) noexcept;
-           void bindSampler(GLuint unit, backend::SamplerParams params) noexcept;
+           void bindSampler(GLuint unit, SamplerParams params) noexcept;
     inline void useProgram(OpenGLProgram* p) noexcept;
 
     enum class ResolveAction { LOAD, STORE };
     void resolvePass(ResolveAction action, GLRenderTarget const* rt,
-            backend::TargetBufferFlags discardFlags) noexcept;
+            TargetBufferFlags discardFlags) noexcept;
 
-    GLuint getSamplerSlow(backend::SamplerParams sp) const noexcept;
+    GLuint getSamplerSlow(SamplerParams sp) const noexcept;
 
-    inline GLuint getSampler(backend::SamplerParams sp) const noexcept {
+    inline GLuint getSampler(SamplerParams sp) const noexcept {
         assert_invariant(!sp.padding0);
         assert_invariant(!sp.padding1);
         assert_invariant(!sp.padding2);
@@ -341,29 +339,29 @@ private:
         return pos->second;
     }
 
-    const std::array<backend::HwSamplerGroup*, backend::Program::BINDING_COUNT>& getSamplerBindings() const {
+    const std::array<HwSamplerGroup*, Program::BINDING_COUNT>& getSamplerBindings() const {
         return mSamplerBindings;
     }
 
-    using AttachmentArray = std::array<GLenum, backend::MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT + 2>;
+    using AttachmentArray = std::array<GLenum, MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT + 2>;
     static GLsizei getAttachments(AttachmentArray& attachments,
-            GLRenderTarget const* rt, backend::TargetBufferFlags buffers) noexcept;
+            GLRenderTarget const* rt, TargetBufferFlags buffers) noexcept;
 
-    backend::RasterState mRasterState;
+    RasterState mRasterState;
 
     // state required to represent the current render pass
-    backend::Handle<backend::HwRenderTarget> mRenderPassTarget;
-    backend::RenderPassParams mRenderPassParams;
+    Handle<HwRenderTarget> mRenderPassTarget;
+    RenderPassParams mRenderPassParams;
     GLboolean mRenderPassColorWrite{};
     GLboolean mRenderPassDepthWrite{};
 
-    void clearWithRasterPipe(backend::TargetBufferFlags clearFlags,
+    void clearWithRasterPipe(TargetBufferFlags clearFlags,
             math::float4 const& linearColor, GLfloat depth, GLint stencil) noexcept;
 
-    void setViewportScissor(backend::Viewport const& viewportScissor) noexcept;
+    void setViewportScissor(Viewport const& viewportScissor) noexcept;
 
     // sampler buffer binding points (nullptr if not used)
-    std::array<backend::HwSamplerGroup*, backend::Program::BINDING_COUNT> mSamplerBindings = {};   // 8 pointers
+    std::array<HwSamplerGroup*, Program::BINDING_COUNT> mSamplerBindings = {};   // 8 pointers
 
     mutable tsl::robin_map<uint32_t, GLuint> mSamplerMap;
     mutable std::vector<GLTexture*> mExternalStreams;
@@ -372,12 +370,12 @@ private:
     void detachStream(GLTexture* t) noexcept;
     void replaceStream(GLTexture* t, GLStream* stream) noexcept;
 
-    backend::OpenGLPlatform& mPlatform;
+    OpenGLPlatform& mPlatform;
 
     OpenGLBlitter* mOpenGLBlitter = nullptr;
-    void updateStreamTexId(GLTexture* t, backend::DriverApi* driver) noexcept;
-    void updateStreamAcquired(GLTexture* t, backend::DriverApi* driver) noexcept;
-    void updateBuffer(GLBufferObject* buffer, backend::BufferDescriptor const& p,
+    void updateStreamTexId(GLTexture* t, DriverApi* driver) noexcept;
+    void updateStreamAcquired(GLTexture* t, DriverApi* driver) noexcept;
+    void updateBuffer(GLBufferObject* buffer, BufferDescriptor const& p,
             uint32_t byteOffset, uint32_t alignment = 16) noexcept;
     void updateTextureLodRange(GLTexture* texture, int8_t targetLevel) noexcept;
 
@@ -393,14 +391,19 @@ private:
     void executeEveryNowAndThenOps() noexcept;
     std::vector<std::function<bool()>> mEveryNowAndThenOps;
 
+    void runAtNextRenderPass(void* token, std::function<void()> fn) noexcept;
+    void executeRenderPassOps() noexcept;
+    void cancelRunAtNextPassOp(void* token) noexcept;
+    tsl::robin_map<void*, std::function<void()>> mRunAtNextRenderPassOps;
+
     // timer query implementation
-    TimerQueryInterface* mTimerQueryImpl = nullptr;
+    OpenGLTimerQueryInterface* mTimerQueryImpl = nullptr;
     bool mFrameTimeSupported = false;
 };
 
 // ------------------------------------------------------------------------------------------------
 
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGLDRIVER_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGLDRIVER_H

filament/backend/src/opengl/OpenGLDriverFactory.h

@@ -14,21 +14,19 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGLDRIVERFACTORY_H
-#define TNT_FILAMENT_DRIVER_OPENGLDRIVERFACTORY_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGLDRIVERFACTORY_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGLDRIVERFACTORY_H
 
-namespace filament {
+namespace filament::backend {
 
-namespace backend {
 class OpenGLPlatform;
 class Driver;
 
 class OpenGLDriverFactory {
 public:
-    static backend::Driver* create(backend::OpenGLPlatform* platform, void* sharedGLContext) noexcept;
+    static Driver* create(OpenGLPlatform* platform, void* sharedGLContext) noexcept;
 };
 
-} // namespace backend
-} // namespace filament
+} // namespace filament::backend
 
-#endif //TNT_FILAMENT_DRIVER_OPENGLDRIVERFACTORY_H
+#endif //TNT_FILAMENT_BACKEND_OPENGL_OPENGLDRIVERFACTORY_H

filament/backend/src/opengl/OpenGLPlatform.cpp

@@ -18,8 +18,7 @@
 
 #include "OpenGLDriverFactory.h"
 
-namespace filament {
-namespace backend {
+namespace filament::backend {
 
 OpenGLPlatform::~OpenGLPlatform() noexcept = default;
 
@@ -27,5 +26,4 @@ Driver* OpenGLPlatform::createDefaultDriver(OpenGLPlatform* platform, void* shar
     return OpenGLDriverFactory::create(platform, sharedContext);
 }
 
-} // namespace backend
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/OpenGLProgram.cpp

@@ -27,51 +27,104 @@
 
 #include <ctype.h>
 
-namespace filament {
+namespace filament::backend {
 
 using namespace filament::math;
 using namespace utils;
 using namespace backend;
 
 static void logCompilationError(utils::io::ostream& out,
-        backend::Program::Shader shaderType, const char* name,
-        GLuint shaderId, std::string_view source) noexcept;
+        Program::Shader shaderType, const char* name,
+        GLuint shaderId, CString const& sourceCode) noexcept;
 
 static void logProgramLinkError(utils::io::ostream& out,
         const char* name, GLuint program) noexcept;
 
-OpenGLProgram::OpenGLProgram(OpenGLDriver* gl, const Program& programBuilder) noexcept
-        :  HwProgram(programBuilder.getName()), mIsValid(false) {
+OpenGLProgram::OpenGLProgram() noexcept
+    : mInitialized(false), mValid(true), mLazyInitializationData(nullptr) {
+}
 
-    using Shader = Program::Shader;
+OpenGLProgram::OpenGLProgram(OpenGLDriver& gld, Program&& programBuilder) noexcept
+        : HwProgram(programBuilder.getName()),
+          mInitialized(false), mValid(true),
+          mLazyInitializationData{ new(LazyInitializationData) } {
 
-    const auto& shadersSource = programBuilder.getShadersSource();
-    OpenGLContext& context = gl->getContext();
+    OpenGLContext& context = gld.getContext();
+
+    mLazyInitializationData->uniformBlockInfo = std::move(programBuilder.getUniformBlockInfo());
+    mLazyInitializationData->samplerGroupInfo = std::move(programBuilder.getSamplerGroupInfo());
+
+    // this cannot fail because we check compilation status after linking the program
+    // shaders[] is filled with id of shader stages present.
+    OpenGLProgram::compileShaders(context, programBuilder.getShadersSource(),
+            gl.shaders, mLazyInitializationData->shaderSourceCode);
+
+    gld.runAtNextRenderPass(this, [this]() {
+        // by this point we must not have a GL program
+        assert_invariant(!gl.program);
+        // we also can't be in the initialized state
+        assert_invariant(!mInitialized);
+        // we must have our lazy initialization data
+        assert_invariant(mLazyInitializationData);
+        // link the program, this also cannot fail because status is checked later.
+        gl.program = OpenGLProgram::linkProgram(gl.shaders);
+    });
+}
+
+OpenGLProgram::~OpenGLProgram() noexcept {
+    if (!mInitialized) {
+        // mLazyInitializationData is aliased with mIndicesRuns
+        delete mLazyInitializationData;
+    }
+    const GLuint program = gl.program;
+    UTILS_NOUNROLL
+    for (GLuint shader: gl.shaders) {
+        if (shader) {
+            if (program) {
+                glDetachShader(program, shader);
+            }
+            glDeleteShader(shader);
+        }
+    }
+    if (program) {
+        glDeleteProgram(program);
+    }
+}
+
+/*
+ * Compile shaders in the ShaderSource. This cannot fail because compilation failures are not
+ * checked until after the program is linked.
+ * This always returns the GL shader IDs or zero a shader stage is not present.
+ */
+void OpenGLProgram::compileShaders(OpenGLContext& context,
+        Program::ShaderSource shadersSource,
+        GLuint shaderIds[Program::SHADER_TYPE_COUNT],
+        std::array<CString, Program::SHADER_TYPE_COUNT>& outShaderSourceCode) noexcept {
 
     // build all shaders
-    #pragma nounroll
+    UTILS_NOUNROLL
     for (size_t i = 0; i < Program::SHADER_TYPE_COUNT; i++) {
+        Program::Shader type = static_cast<Program::Shader>(i);
         GLenum glShaderType;
-        Shader type = (Shader)i;
         switch (type) {
-            case Shader::VERTEX:
+            case Program::Shader::VERTEX:
                 glShaderType = GL_VERTEX_SHADER;
                 break;
-            case Shader::FRAGMENT:
+            case Program::Shader::FRAGMENT:
                 glShaderType = GL_FRAGMENT_SHADER;
                 break;
         }
 
-        if (!shadersSource[i].empty()) {
-            GLint status;
-            Program::ShaderBlob shader = shadersSource[i];
+        if (UTILS_LIKELY(!shadersSource[i].empty())) {
+            Program::ShaderBlob const& shader = shadersSource[i];
+            std::string_view shaderView(reinterpret_cast<const char*>(shader.data()), shader.size());
             std::string temp;
-            std::string_view shaderView((const char*)shader.data(), shader.size());
 
             if (!context.ext.GOOGLE_cpp_style_line_directive) {
                 // If usages of the Google-style line directive are present, remove them, as some
                 // drivers don't allow the quotation marks.
-                if (UTILS_UNLIKELY(requestsGoogleLineDirectivesExtension(shaderView.data(), shaderView.size()))) {
+                if (UTILS_UNLIKELY(requestsGoogleLineDirectivesExtension(
+                        shaderView.data(), shaderView.size()))) {
                     temp = shaderView; // copy string
                     removeGoogleLineDirectives(temp.data(), temp.size()); // length is unaffected
                     shaderView = temp;
@@ -136,159 +189,179 @@ highp uint packHalf2x16(vec2 v) {
                 const GLint length = (GLint)shaderView.length();
                 glShaderSource(shaderId, 1, &source, &length);
                 glCompileShader(shaderId);
+#ifndef NDEBUG
+                outShaderSourceCode[i] = { source, static_cast<size_t>(length) };
+#endif
             }
-
-            glGetShaderiv(shaderId, GL_COMPILE_STATUS, &status);
-            if (UTILS_UNLIKELY(status != GL_TRUE)) {
-                logCompilationError(slog.e, type,
-                        programBuilder.getName().c_str_safe(), shaderId, shaderView);
-                glDeleteShader(shaderId);
-                return;
-            }
-            this->gl.shaders[i] = shaderId;
-            mValidShaderSet |= 1U << i;
+            shaderIds[i] = shaderId;
         }
     }
-
-    // we need at least a vertex and fragment program
-    const uint8_t validShaderSet = mValidShaderSet;
-    const uint8_t mask = VERTEX_SHADER_BIT | FRAGMENT_SHADER_BIT;
-    if (UTILS_LIKELY((mValidShaderSet & mask) == mask)) {
-        GLint status;
-        GLuint program = glCreateProgram();
-        for (size_t i = 0; i < Program::SHADER_TYPE_COUNT; i++) {
-            if (validShaderSet & (1U << i)) {
-                glAttachShader(program, this->gl.shaders[i]);
-            }
-        }
-        glLinkProgram(program);
-
-        glGetProgramiv(program, GL_LINK_STATUS, &status);
-        if (UTILS_UNLIKELY(status != GL_TRUE)) {
-            logProgramLinkError(slog.e, programBuilder.getName().c_str_safe(), program);
-            glDeleteProgram(program);
-            return;
-        }
-
-        this->gl.program = program;
-
-        // Associate each UniformBlock in the program to a known binding.
-        auto const& uniformBlockInfo = programBuilder.getUniformBlockInfo();
-        #pragma nounroll
-        for (GLuint binding = 0, n = uniformBlockInfo.size(); binding < n; binding++) {
-            auto const& name = uniformBlockInfo[binding];
-            if (!name.empty()) {
-                GLint index = glGetUniformBlockIndex(program, name.c_str());
-                if (index >= 0) {
-                    glUniformBlockBinding(program, GLuint(index), binding);
-                }
-                CHECK_GL_ERROR(utils::slog.e)
-            }
-        }
-
-        if (programBuilder.hasSamplers()) {
-            // if we have samplers, we need to do a bit of extra work
-            // activate this program so we can set all its samplers once and for all (glUniform1i)
-            context.useProgram(program);
-
-            auto const& samplerGroupInfo = programBuilder.getSamplerGroupInfo();
-            auto& indicesRun = mIndicesRuns;
-            uint8_t numUsedBindings = 0;
-            uint8_t tmu = 0;
-
-            #pragma nounroll
-            for (size_t i = 0, c = samplerGroupInfo.size(); i < c; i++) {
-                auto const& groupInfo = samplerGroupInfo[i];
-                auto const& samplers = groupInfo.samplers;
-                if (!samplers.empty()) {
-                    // Cache the sampler uniform locations for each interface block
-                    BlockInfo& info = mBlockInfos[numUsedBindings];
-                    info.binding = uint8_t(i);
-                    uint8_t count = 0;
-                    for (uint8_t j = 0, m = uint8_t(samplers.size()); j < m; ++j) {
-                        // find its location and associate a TMU to it
-                        GLint loc = glGetUniformLocation(program, samplers[j].name.c_str());
-                        if (loc >= 0) {
-                            glUniform1i(loc, tmu);
-                            indicesRun[tmu] = j;
-                            count++;
-                            tmu++;
-                        } else {
-                            // glGetUniformLocation could fail if the uniform is not used
-                            // in the program. We should just ignore the error in that case.
-                        }
-                    }
-                    if (count > 0) {
-                        numUsedBindings++;
-                        info.count = uint8_t(count - 1);
-                    }
-                }
-            }
-            mUsedBindingsCount = numUsedBindings;
-        }
-        mIsValid = true;
-    }
-
-    // Failing to compile a program can't be fatal, because this will happen a lot in
-    // the material tools. We need to have a better way to handle these errors and
-    // return to the editor. Also note the early "return" statements in this function.
-    if (UTILS_UNLIKELY(!isValid())) {
-        PANIC_LOG("Failed to compile GLSL program.");
-    }
 }
 
-OpenGLProgram::~OpenGLProgram() noexcept {
-    const size_t validShaderSet = mValidShaderSet;
-    const bool isValid = mIsValid;
-    GLuint program = gl.program;
-    if (validShaderSet) {
-        UTILS_NOUNROLL
-        for (size_t i = 0; i < Program::SHADER_TYPE_COUNT; i++) {
-            if (validShaderSet & (1U << i)) {
-                const GLuint shader = gl.shaders[i];
-                if (isValid) {
-                    glDetachShader(program, shader);
-                }
-                glDeleteShader(shader);
-            }
+/*
+ * Create a program from the given shader IDs and links it. This cannot fail because errors
+ * are checked later. This always returns a valid GL program ID (which doesn't mean the
+ * program itself is valid).
+ */
+GLuint OpenGLProgram::linkProgram(const GLuint shaderIds[Program::SHADER_TYPE_COUNT]) noexcept {
+    GLuint program = glCreateProgram();
+    for (size_t i = 0; i < Program::SHADER_TYPE_COUNT; i++) {
+        if (shaderIds[i]) {
+            glAttachShader(program, shaderIds[i]);
         }
     }
-    if (isValid) {
-        glDeleteProgram(program);
+    glLinkProgram(program);
+    return program;
+}
+
+/*
+ * Checks a program link status and logs errors and frees resources on failure.
+ * Returns true on success.
+ */
+bool OpenGLProgram::checkProgramStatus(const char* name,
+        GLuint& program, GLuint shaderIds[Program::SHADER_TYPE_COUNT],
+        std::array<CString, 2> const& shaderSourceCode) noexcept {
+
+    GLint status;
+    glGetProgramiv(program, GL_LINK_STATUS, &status);
+    if (UTILS_LIKELY(status == GL_TRUE)) {
+        return true;
     }
+
+    // only if the link fails, we check the compilation status
+    UTILS_NOUNROLL
+    for (size_t i = 0; i < Program::SHADER_TYPE_COUNT; i++) {
+        const Program::Shader type = static_cast<Program::Shader>(i);
+        const GLuint shader = shaderIds[i];
+        glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
+        if (status != GL_TRUE) {
+            logCompilationError(slog.e, type, name, shader, shaderSourceCode[i]);
+        }
+        glDetachShader(program, shader);
+        glDeleteShader(shader);
+        shaderIds[i] = 0;
+    }
+    // log the link error as well
+    logProgramLinkError(slog.e, name, program);
+    glDeleteProgram(program);
+    program = 0;
+    return false;
+}
+
+void OpenGLProgram::initialize(OpenGLContext& context) {
+    // by this point we must have a GL program
+    assert_invariant(gl.program);
+    // we also can't be in the initialized state
+    assert_invariant(!mInitialized);
+    // we must have our lazy initialization data
+    assert_invariant(mLazyInitializationData);
+
+    // we must copy mLazyInitializationData locally because it is aliased with mIndicesRuns
+    auto* const initializationData = mLazyInitializationData;
+
+    // check status of program linking and shader compilation, logs error and free all resources
+    // in case of error.
+    mValid = OpenGLProgram::checkProgramStatus(name.c_str_safe(),
+            gl.program, gl.shaders, initializationData->shaderSourceCode);
+
+    if (mValid) {
+        initializeProgramState(context, gl.program,
+                initializationData->uniformBlockInfo,
+                initializationData->samplerGroupInfo);
+    }
+
+    // and destroy all temporary init data
+    delete initializationData;
+    // mInitialized means mLazyInitializationData is no more valid
+    mInitialized = true;
+}
+
+/*
+ * Initializes our internal state from a valid program. This must only be called after
+ * checkProgramStatus() has been successfully called.
+ */
+void OpenGLProgram::initializeProgramState(OpenGLContext& context, GLuint program,
+        Program::UniformBlockInfo const& uniformBlockInfo,
+        Program::SamplerGroupInfo const& samplerGroupInfo) noexcept {
+
+    // Associate each UniformBlock in the program to a known binding.
+    UTILS_NOUNROLL
+    for (GLuint binding = 0, n = uniformBlockInfo.size(); binding < n; binding++) {
+        auto const& name = uniformBlockInfo[binding];
+        if (!name.empty()) {
+            GLint index = glGetUniformBlockIndex(program, name.c_str());
+            if (index >= 0) {
+                glUniformBlockBinding(program, GLuint(index), binding);
+            }
+            CHECK_GL_ERROR(utils::slog.e)
+        }
+    }
+
+    uint8_t usedBindingCount = 0;
+    uint8_t tmu = 0;
+
+    UTILS_NOUNROLL
+    for (size_t i = 0, c = samplerGroupInfo.size(); i < c; i++) {
+        auto const& samplers = 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 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 SamplerGroup, just cancel the
+        // whole group.
+        if (atLeastOneSamplerUsed) {
+            // Cache the sampler uniform locations for each interface block
+            mUsedBindingPoints[usedBindingCount] = i;
+            usedBindingCount++;
+        } else {
+            tmu -= samplers.size();
+        }
+    }
+    mUsedBindingsCount = usedBindingCount;
 }
 
 void OpenGLProgram::updateSamplers(OpenGLDriver* gld) noexcept {
     using GLTexture = OpenGLDriver::GLTexture;
 
-    // cache a few member variable locally, outside of the loop
-    OpenGLContext& glc = gld->getContext();
-    const bool anisotropyWorkaround = glc.ext.EXT_texture_filter_anisotropic &&
-                                      glc.bugs.texture_filter_anisotropic_broken_on_sampler;
-    auto const& UTILS_RESTRICT samplerBindings = gld->getSamplerBindings();
-    auto const& UTILS_RESTRICT indicesRun = mIndicesRuns;
-    auto const& UTILS_RESTRICT blockInfos = mBlockInfos;
-
-    UTILS_ASSUME(mUsedBindingsCount > 0);
-    for (uint8_t i = 0, tmu = 0, n = mUsedBindingsCount; i < n; i++) {
-        BlockInfo blockInfo = blockInfos[i];
-        HwSamplerGroup const * const UTILS_RESTRICT hwsb = samplerBindings[blockInfo.binding];
-        if (UTILS_UNLIKELY(!hwsb)) {
-            tmu += blockInfo.count + 1;
-            continue;
-        }
-        SamplerGroup const& UTILS_RESTRICT sb = *(hwsb->sb);
-        SamplerGroup::Sampler const* const UTILS_RESTRICT samplers = sb.getSamplers();
-        for (uint8_t j = 0, m = blockInfo.count ; j <= m; ++j, ++tmu) { // "<=" on purpose here
-            const uint8_t index = indicesRun[tmu];
-            assert_invariant(index < sb.getSize());
-
-            Handle<HwTexture> th = samplers[index].t;
-            if (UTILS_UNLIKELY(!th)) {
-#ifndef NDEBUG
-                slog.w << "In material " << name.c_str()
-                       << ": no texture bound to unit " << +index << io::endl;
+    // cache a few member variable locally, outside the loop
+    OpenGLContext& context = gld->getContext();
+#if defined(GL_EXT_texture_filter_anisotropic)
+    const bool anisotropyWorkaround = context.ext.EXT_texture_filter_anisotropic &&
+                                      context.bugs.texture_filter_anisotropic_broken_on_sampler;
 #endif
+    auto const& UTILS_RESTRICT samplerBindings = gld->getSamplerBindings();
+    auto const& UTILS_RESTRICT usedBindingPoints = mUsedBindingPoints;
+
+    for (uint8_t i = 0, tmu = 0, n = mUsedBindingsCount; i < n; i++) {
+        const auto binding = usedBindingPoints[i];
+        HwSamplerGroup const * const hwsb = samplerBindings[binding];
+        assert_invariant(hwsb);
+
+        SamplerGroup const& sb = *(hwsb->sb);
+        SamplerGroup::Sampler const* const samplers = sb.getSamplers();
+        for (uint8_t j = 0, m = sb.getSize(); j < m; ++j, ++tmu) { // "<=" on purpose here
+            Handle<HwTexture> th = samplers[j].t;
+            if (!th) {
+                // this happens if the program doesn't use all samplers of a sampler group,
+                // which is not an error.
                 continue;
             }
 
@@ -299,7 +372,7 @@ void OpenGLProgram::updateSamplers(OpenGLDriver* gld) noexcept {
                 t->gl.fence = nullptr;
             }
 
-            SamplerParams params{ samplers[index].s };
+            SamplerParams params{ samplers[j].s };
             if (UTILS_UNLIKELY(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
@@ -316,9 +389,9 @@ void OpenGLProgram::updateSamplers(OpenGLDriver* gld) noexcept {
                 && params.filterMag != SamplerMagFilter::NEAREST
                 && params.filterMin != SamplerMinFilter::NEAREST
                 && params.filterMin != SamplerMinFilter::NEAREST_MIPMAP_NEAREST) {
-                slog.w << "In material " << name.c_str()
+                slog.w << "In program " << name.c_str()
                        << ": depth texture used with filtering sampler, tmu = "
-                       << +index << io::endl;
+                       << +tmu << io::endl;
             }
 #endif
             gld->bindTexture(tmu, t);
@@ -331,7 +404,7 @@ void OpenGLProgram::updateSamplers(OpenGLDriver* gld) noexcept {
                 // The texture is already bound here.
                 GLfloat anisotropy = float(1u << params.anisotropyLog2);
                 glTexParameterf(t->gl.target, GL_TEXTURE_MAX_ANISOTROPY_EXT,
-                        std::min(glc.gets.max_anisotropy, anisotropy));
+                        std::min(context.gets.max_anisotropy, anisotropy));
             }
 #endif
         }
@@ -341,7 +414,7 @@ void OpenGLProgram::updateSamplers(OpenGLDriver* gld) noexcept {
 
 UTILS_NOINLINE
 void logCompilationError(io::ostream& out, Program::Shader shaderType,
-        const char* name, GLuint shaderId, std::string_view shader) noexcept {
+        const char* name, GLuint shaderId, CString const& sourceCode) noexcept {
 
     auto to_string = [](Program::Shader type) -> const char* {
         switch (type) {
@@ -350,13 +423,20 @@ void logCompilationError(io::ostream& out, Program::Shader shaderType,
         }
     };
 
-    char error[1024];
-    glGetShaderInfoLog(shaderId, sizeof(error), nullptr, error);
+    { // scope for the temporary string storage
+        GLint length = 0;
+        glGetShaderiv(shaderId, GL_INFO_LOG_LENGTH, &length);
 
-    out << "Compilation error in " << to_string(shaderType) << " shader \"" << name << "\":\n"
-        << "\"" << error << "\""
-        << io::endl;
+        CString infoLog(length);
+        glGetShaderInfoLog(shaderId, length, nullptr, infoLog.data());
 
+        out << "Compilation error in " << to_string(shaderType) << " shader \"" << name << "\":\n"
+            << "\"" << infoLog.c_str() << "\""
+            << io::endl;
+    }
+
+#ifndef NDEBUG
+    std::string_view shader{ sourceCode.data(), sourceCode.size() };
     size_t lc = 1;
     size_t start = 0;
     std::string line;
@@ -367,23 +447,27 @@ void logCompilationError(io::ostream& out, Program::Shader shaderType,
         } else {
             line = shader.substr(start, end - start);
         }
-        out << lc++ << ":   "<< line.c_str() << '\n';
+        out << lc++ << ":   " << line.c_str() << '\n';
         if (end == std::string::npos) {
             break;
         }
         start = end + 1;
     }
     out << io::endl;
+#endif
 }
 
 UTILS_NOINLINE
 void logProgramLinkError(io::ostream& out, char const* name, GLuint program) noexcept {
-    char error[1024];
-    glGetProgramInfoLog(program, sizeof(error), nullptr, error);
+    GLint length = 0;
+    glGetProgramiv(program, GL_INFO_LOG_LENGTH, &length);
+
+    CString infoLog(length);
+    glGetProgramInfoLog(program, length, nullptr, infoLog.data());
 
     out << "Link error in \"" << name << "\":\n"
-        << "\"" << error << "\""
+        << "\"" << infoLog.c_str() << "\""
         << io::endl;
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/OpenGLProgram.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGLPROGRAM_H
-#define TNT_FILAMENT_DRIVER_OPENGLPROGRAM_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGLPROGRAM_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGLPROGRAM_H
 
 #include "DriverBase.h"
 #include "OpenGLDriver.h"
@@ -32,18 +32,23 @@
 #include <stdint.h>
 
 
-namespace filament {
+namespace filament::backend {
 
-class OpenGLProgram : public backend::HwProgram {
+class OpenGLProgram : public HwProgram {
 public:
 
-    OpenGLProgram() noexcept = default;
-    OpenGLProgram(OpenGLDriver* gl, const backend::Program& builder) noexcept;
+    OpenGLProgram() noexcept;
+    OpenGLProgram(OpenGLDriver& gld, Program&& builder) noexcept;
     ~OpenGLProgram() noexcept;
 
-    bool isValid() const noexcept { return mIsValid; }
+    bool isValid() const noexcept { return mValid; }
 
-    void use(OpenGLDriver* const gl) noexcept {
+    void use(OpenGLDriver* const gld, OpenGLContext& context) noexcept {
+        if (UTILS_UNLIKELY(!mInitialized)) {
+            initialize(context);
+        }
+
+        context.useProgram(gl.program);
         if (UTILS_UNLIKELY(mUsedBindingsCount)) {
             // We rely on GL state tracking to avoid unnecessary glBindTexture / glBindSampler
             // calls.
@@ -57,49 +62,67 @@ public:
             // a bit less. Compared to what updateSamplers() actually does, which is
             // pretty little, I'm not sure we'll get ahead.
 
-            updateSamplers(gl);
+            updateSamplers(gld);
         }
     }
 
     struct {
-        GLuint shaders[backend::Program::SHADER_TYPE_COUNT];
-        GLuint program;
+        GLuint shaders[Program::SHADER_TYPE_COUNT] = {};
+        GLuint program = 0;
     } gl; // 12 bytes
 
 private:
     static constexpr uint8_t TEXTURE_UNIT_COUNT = OpenGLContext::MAX_TEXTURE_UNIT_COUNT;
-    static constexpr uint8_t VERTEX_SHADER_BIT   = uint8_t(1) << size_t(backend::Program::Shader::VERTEX);
-    static constexpr uint8_t FRAGMENT_SHADER_BIT = uint8_t(1) << size_t(backend::Program::Shader::FRAGMENT);
+    static constexpr uint8_t VERTEX_SHADER_BIT   = uint8_t(1) << size_t(Program::Shader::VERTEX);
+    static constexpr uint8_t FRAGMENT_SHADER_BIT = uint8_t(1) << size_t(Program::Shader::FRAGMENT);
 
-    struct BlockInfo {
-        uint8_t binding : 3;    // binding (i.e.: index in mSamplerBindings)
-        uint8_t count   : 5;    // number of TMUs actually used minus 1
+    static void compileShaders(OpenGLContext& context,
+            Program::ShaderSource shadersSource,
+            GLuint shaderIds[Program::SHADER_TYPE_COUNT],
+            std::array<utils::CString, Program::SHADER_TYPE_COUNT>& outShaderSourceCode) noexcept;
 
-        // if TEXTURE_UNIT_COUNT > 32, the count bitfield must be increased accordingly
-        static_assert(TEXTURE_UNIT_COUNT <= 32, "TEXTURE_UNIT_COUNT must be <= 32");
+    static GLuint linkProgram(const GLuint shaderIds[Program::SHADER_TYPE_COUNT]) noexcept;
 
-        // if SAMPLER_BINDING_COUNT > 8, the binding bitfield must be increased accordingly
-        static_assert(backend::Program::BINDING_COUNT <= 8, "BINDING_COUNT must be <= 8");
-    };
+    static bool checkProgramStatus(const char* name,
+            GLuint& program, GLuint shaderIds[Program::SHADER_TYPE_COUNT],
+            std::array<utils::CString, 2> const& shaderSourceCode) noexcept;
 
-    // This assert checks that the struct is the size we expect without any "hidden" padding bytes
-    // inserted by the compiler.
-    static_assert(sizeof(BlockInfo) == sizeof(uint8_t), "BlockInfo must be 8 bits");
+    void initialize(OpenGLContext& context);
 
-    uint8_t mUsedBindingsCount = 0;
-    uint8_t mValidShaderSet = 0;
-    bool mIsValid = false;
-
-    // information about each USED sampler buffer (no gaps)
-    std::array<BlockInfo, backend::Program::BINDING_COUNT> mBlockInfos;   // 8 bytes
-
-    // runs of indices into SamplerGroup -- run start index and size given by BlockInfo
-    std::array<uint8_t, TEXTURE_UNIT_COUNT> mIndicesRuns;    // 16 bytes
+    void initializeProgramState(OpenGLContext& context, GLuint program,
+            Program::UniformBlockInfo const& uniformBlockInfo,
+            Program::SamplerGroupInfo const& samplerGroupInfo) noexcept;
 
     void updateSamplers(OpenGLDriver* gld) noexcept;
+
+    // keep these away from of other class attributes
+    struct LazyInitializationData {
+        Program::UniformBlockInfo uniformBlockInfo;
+        Program::SamplerGroupInfo samplerGroupInfo;
+        std::array<utils::CString, Program::SHADER_TYPE_COUNT> shaderSourceCode;
+    };
+
+    // number of bindings actually used by this program
+    uint8_t mUsedBindingsCount = 0u;
+    // whether lazy initialization has been performed
+    bool mInitialized : 1;
+    // whether lazy initialization was successful
+    bool mValid : 1;
+    UTILS_UNUSED uint8_t padding[2] = {};
+
+    union {
+        // when mInitialized == true:
+        // information about each USED sampler buffer per binding (no gaps)
+        std::array<uint8_t, Program::BINDING_COUNT> mUsedBindingPoints;   // 8 bytes
+        // when mInitialized == false:
+        // lazy initialization data pointer
+        LazyInitializationData* mLazyInitializationData;
+    };
 };
 
+// if OpenGLProgram is larger tha 64 bytes, it'll fall in a larger Handle bucket.
+static_assert(sizeof(OpenGLProgram) <= 64);
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGLPROGRAM_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGLPROGRAM_H

filament/backend/src/opengl/OpenGLTimerQuery.cpp

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#include "TimerQuery.h"
+#include "OpenGLTimerQuery.h"
 
 #include "private/backend/OpenGLPlatform.h"
 
@@ -23,14 +23,14 @@
 #include <utils/Systrace.h>
 #include <utils/debug.h>
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 using namespace GLUtils;
 
 // ------------------------------------------------------------------------------------------------
 
-TimerQueryInterface::~TimerQueryInterface() = default;
+OpenGLTimerQueryInterface::~OpenGLTimerQueryInterface() = default;
 
 // ------------------------------------------------------------------------------------------------
 
@@ -72,7 +72,7 @@ uint64_t TimerQueryNative::queryResult(GLTimerQuery* query) {
 
 // ------------------------------------------------------------------------------------------------
 
-TimerQueryFence::TimerQueryFence(backend::OpenGLPlatform& platform)
+OpenGLTimerQueryFence::OpenGLTimerQueryFence(OpenGLPlatform& platform)
         : mPlatform(platform) {
     mQueue.reserve(2);
     mThread = std::thread([this]() {
@@ -94,7 +94,7 @@ TimerQueryFence::TimerQueryFence(backend::OpenGLPlatform& platform)
     });
 }
 
-TimerQueryFence::~TimerQueryFence() {
+OpenGLTimerQueryFence::~OpenGLTimerQueryFence() {
     if (mThread.joinable()) {
         std::unique_lock<utils::Mutex> lock(mLock);
         mExitRequested = true;
@@ -104,13 +104,13 @@ TimerQueryFence::~TimerQueryFence() {
     }
 }
 
-void TimerQueryFence::enqueue(TimerQueryFence::Job&& job) {
+void OpenGLTimerQueryFence::enqueue(OpenGLTimerQueryFence::Job&& job) {
     std::unique_lock<utils::Mutex> lock(mLock);
     mQueue.push_back(std::forward<Job>(job));
     mCondition.notify_one();
 }
 
-void TimerQueryFence::flush() {
+void OpenGLTimerQueryFence::flush() {
     // Use calls to flush() as a proxy for when the GPU work started.
     GLTimerQuery* query = mActiveQuery;
     if (query) {
@@ -124,7 +124,7 @@ void TimerQueryFence::flush() {
     }
 }
 
-void TimerQueryFence::beginTimeElapsedQuery(GLTimerQuery* query) {
+void OpenGLTimerQueryFence::beginTimeElapsedQuery(GLTimerQuery* query) {
     assert_invariant(!mActiveQuery);
     // We can't use a fence to figure out when a GPU operation starts (only when it finishes)
     // so instead, we use when glFlush() was issued as a proxy.
@@ -136,7 +136,7 @@ void TimerQueryFence::beginTimeElapsedQuery(GLTimerQuery* query) {
     mActiveQuery = query;
 }
 
-void TimerQueryFence::endTimeElapsedQuery(GLTimerQuery* query) {
+void OpenGLTimerQueryFence::endTimeElapsedQuery(GLTimerQuery* query) {
     assert_invariant(mActiveQuery);
     Platform::Fence* fence = mPlatform.createFence();
     std::weak_ptr<GLTimerQuery::State> weak = query->gl.emulation;
@@ -157,11 +157,11 @@ void TimerQueryFence::endTimeElapsedQuery(GLTimerQuery* query) {
     });
 }
 
-bool TimerQueryFence::queryResultAvailable(GLTimerQuery* query) {
+bool OpenGLTimerQueryFence::queryResultAvailable(GLTimerQuery* query) {
     return query->gl.emulation->available.load();
 }
 
-uint64_t TimerQueryFence::queryResult(GLTimerQuery* query) {
+uint64_t OpenGLTimerQueryFence::queryResult(GLTimerQuery* query) {
     return query->gl.emulation->elapsed;
 }
 
@@ -174,7 +174,7 @@ TimerQueryFallback::~TimerQueryFallback() = default;
 void TimerQueryFallback::flush() {
 }
 
-void TimerQueryFallback::beginTimeElapsedQuery(TimerQueryInterface::GLTimerQuery* query) {
+void TimerQueryFallback::beginTimeElapsedQuery(OpenGLTimerQueryInterface::GLTimerQuery* query) {
     if (!query->gl.emulation) {
         query->gl.emulation = std::make_shared<GLTimerQuery::State>();
     }
@@ -183,18 +183,18 @@ void TimerQueryFallback::beginTimeElapsedQuery(TimerQueryInterface::GLTimerQuery
     query->gl.emulation->elapsed = clock::now().time_since_epoch().count();
 }
 
-void TimerQueryFallback::endTimeElapsedQuery(TimerQueryInterface::GLTimerQuery* query) {
+void TimerQueryFallback::endTimeElapsedQuery(OpenGLTimerQueryInterface::GLTimerQuery* query) {
     // this implementation clearly doesn't work at all, but we have no h/w support
     query->gl.emulation->elapsed = clock::now().time_since_epoch().count() - query->gl.emulation->elapsed;
     query->gl.emulation->available.store(true, std::memory_order_relaxed);
 }
 
-bool TimerQueryFallback::queryResultAvailable(TimerQueryInterface::GLTimerQuery* query) {
+bool TimerQueryFallback::queryResultAvailable(OpenGLTimerQueryInterface::GLTimerQuery* query) {
     return query->gl.emulation->available.load(std::memory_order_relaxed);
 }
 
-uint64_t TimerQueryFallback::queryResult(TimerQueryInterface::GLTimerQuery* query) {
+uint64_t TimerQueryFallback::queryResult(OpenGLTimerQueryInterface::GLTimerQuery* query) {
     return query->gl.emulation->elapsed;
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/OpenGLTimerQuery.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_TIMERQUERY_H
-#define TNT_FILAMENT_DRIVER_TIMERQUERY_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_TIMERQUERY_H
+#define TNT_FILAMENT_BACKEND_OPENGL_TIMERQUERY_H
 
 #include "OpenGLDriver.h"
 
@@ -24,7 +24,7 @@
 #include <thread>
 #include <vector>
 
-namespace filament {
+namespace filament::backend {
 
 /*
  * we need two implementation of timer queries (only elapsed time), because
@@ -34,13 +34,13 @@ namespace filament {
  * These classes implement the various strategies...
  */
 
-class TimerQueryInterface {
+class OpenGLTimerQueryInterface {
 protected:
     using GLTimerQuery = OpenGLDriver::GLTimerQuery;
     using clock = std::chrono::steady_clock;
 
 public:
-    virtual ~TimerQueryInterface();
+    virtual ~OpenGLTimerQueryInterface();
     virtual void flush() = 0;
     virtual void beginTimeElapsedQuery(GLTimerQuery* query) = 0;
     virtual void endTimeElapsedQuery(GLTimerQuery* query) = 0;
@@ -48,7 +48,7 @@ public:
     virtual uint64_t queryResult(GLTimerQuery* query) = 0;
 };
 
-class TimerQueryNative : public TimerQueryInterface {
+class TimerQueryNative : public OpenGLTimerQueryInterface {
 public:
     explicit TimerQueryNative(OpenGLContext& context);
     ~TimerQueryNative() override;
@@ -61,10 +61,10 @@ private:
     OpenGLContext& gl;
 };
 
-class TimerQueryFence : public TimerQueryInterface {
+class OpenGLTimerQueryFence : public OpenGLTimerQueryInterface {
 public:
-    explicit TimerQueryFence(backend::OpenGLPlatform& platform);
-    ~TimerQueryFence() override;
+    explicit OpenGLTimerQueryFence(OpenGLPlatform& platform);
+    ~OpenGLTimerQueryFence() override;
 private:
     using Job = std::function<void()>;
     void flush() override;
@@ -79,7 +79,7 @@ private:
         enqueue(Job(std::bind(std::forward<CALLABLE>(func), std::forward<ARGS>(args)...)));
     }
 
-    backend::OpenGLPlatform& mPlatform;
+    OpenGLPlatform& mPlatform;
     std::thread mThread;
     mutable utils::Mutex mLock;
     mutable utils::Condition mCondition;
@@ -88,7 +88,7 @@ private:
     GLTimerQuery* mActiveQuery = nullptr;
 };
 
-class TimerQueryFallback : public TimerQueryInterface {
+class TimerQueryFallback : public OpenGLTimerQueryInterface {
 public:
     explicit TimerQueryFallback();
     ~TimerQueryFallback() override;
@@ -100,6 +100,6 @@ private:
     uint64_t queryResult(GLTimerQuery* query) override;
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif //TNT_FILAMENT_DRIVER_TIMERQUERY_H
+#endif //TNT_FILAMENT_BACKEND_OPENGL_TIMERQUERY_H

filament/backend/src/opengl/gl_headers.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_GL_HEADERS_H
-#define TNT_FILAMENT_DRIVER_GL_HEADERS_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_GL_HEADERS_H
+#define TNT_FILAMENT_BACKEND_OPENGL_GL_HEADERS_H
 
 #if defined(__ANDROID__) || defined(FILAMENT_USE_EXTERNAL_GLES3) || defined(__EMSCRIPTEN__)
 
@@ -144,4 +144,4 @@
 #define GL41_HEADERS false
 #endif
 
-#endif // TNT_FILAMENT_DRIVER_GL_HEADERS_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_GL_HEADERS_H

filament/backend/src/opengl/platforms/CocoaTouchExternalImage.h

@@ -21,7 +21,7 @@
 
 #include <CoreVideo/CoreVideo.h>
 
-namespace filament {
+namespace filament::backend {
 
 class CocoaTouchExternalImage final {
 public:
@@ -95,6 +95,6 @@ private:
 
 };
 
-} // namespace filament
+} // namespace filament::backend
 
 #endif

filament/backend/src/opengl/platforms/CocoaTouchExternalImage.mm

@@ -29,7 +29,7 @@
 #include <utils/Panic.h>
 #include <utils/debug.h>
 
-namespace filament {
+namespace filament::backend {
 
 static const char* s_vertexES = R"SHADER(#version 300 es
 in vec4 pos;
@@ -317,4 +317,4 @@ void CocoaTouchExternalImage::State::restore() noexcept {
     }
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/platforms/ExternalStreamManagerAndroid.cpp

@@ -26,7 +26,7 @@
 
 using namespace utils;
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 using Stream = Platform::Stream;
@@ -166,4 +166,4 @@ void ExternalStreamManagerAndroid::updateTexImage(Stream* handle, int64_t* times
     }
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/platforms/ExternalStreamManagerAndroid.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_ANDROID_EXTERNAL_STREAM_MANAGER_ANDROID_H
-#define TNT_FILAMENT_DRIVER_ANDROID_EXTERNAL_STREAM_MANAGER_ANDROID_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_ANDROID_EXTERNAL_STREAM_MANAGER_ANDROID_H
+#define TNT_FILAMENT_BACKEND_OPENGL_ANDROID_EXTERNAL_STREAM_MANAGER_ANDROID_H
 
 #include "private/backend/VirtualMachineEnv.h"
 
@@ -29,7 +29,7 @@ struct ASurfaceTexture;
 typedef struct ASurfaceTexture ASurfaceTexture;
 #endif
 
-namespace filament {
+namespace filament::backend {
 
 /*
  * ExternalStreamManagerAndroid::Stream is basically a wrapper for SurfaceTexture.
@@ -38,7 +38,7 @@ namespace filament {
  */
 class ExternalStreamManagerAndroid {
 public:
-    using Stream = backend::Platform::Stream;
+    using Stream = Platform::Stream;
 
     // must be called on GLES thread
     static ExternalStreamManagerAndroid& create() noexcept;
@@ -86,6 +86,6 @@ private:
     jmethodID mSurfaceTextureClass_detachFromGLContext{};
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif //TNT_FILAMENT_DRIVER_ANDROID_EXTERNAL_STREAM_MANAGER_ANDROID_H
+#endif //TNT_FILAMENT_BACKEND_OPENGL_ANDROID_EXTERNAL_STREAM_MANAGER_ANDROID_H

filament/backend/src/opengl/platforms/PlatformCocoaGL.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_COCOA_GL_H
-#define TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_COCOA_GL_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_COCOA_GL_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_COCOA_GL_H
 
 #include <stdint.h>
 
@@ -23,16 +23,16 @@
 
 #include "private/backend/OpenGLPlatform.h"
 
-namespace filament {
+namespace filament::backend {
 
 struct PlatformCocoaGLImpl;
 
-class PlatformCocoaGL final : public backend::OpenGLPlatform {
+class PlatformCocoaGL final : public OpenGLPlatform {
 public:
     PlatformCocoaGL();
     ~PlatformCocoaGL() noexcept final;
 
-    backend::Driver* createDriver(void* sharedContext) noexcept override;
+    Driver* createDriver(void* sharedContext) noexcept override;
     void terminate() noexcept final;
 
     SwapChain* createSwapChain(void* nativewindow, uint64_t& flags) noexcept final;
@@ -43,8 +43,8 @@ public:
 
     Fence* createFence() noexcept final { return nullptr; }
     void destroyFence(Fence* fence) noexcept final {}
-    backend::FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept final {
-        return backend::FenceStatus::ERROR;
+    FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept final {
+        return FenceStatus::ERROR;
     }
 
     void setPresentationTime(int64_t presentationTimeInNanosecond) noexcept final {}
@@ -57,7 +57,7 @@ public:
 
     ExternalTexture* createExternalTextureStorage() noexcept final { return nullptr; }
     void reallocateExternalStorage(ExternalTexture* ets,
-            uint32_t w, uint32_t h, backend::TextureFormat format) noexcept final { }
+            uint32_t w, uint32_t h, TextureFormat format) noexcept final { }
     void destroyExternalTextureStorage(ExternalTexture* ets) noexcept final { }
 
     int getOSVersion() const noexcept final { return 0; }
@@ -68,6 +68,6 @@ private:
     PlatformCocoaGLImpl* pImpl = nullptr;
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_COCOA_GL_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_COCOA_GL_H

filament/backend/src/opengl/platforms/PlatformCocoaGL.mm

@@ -30,7 +30,7 @@
 
 #include <vector>
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 
@@ -171,7 +171,7 @@ void PlatformCocoaGL::terminate() noexcept {
 
 Platform::SwapChain* PlatformCocoaGL::createSwapChain(void* nativewindow, uint64_t& flags) noexcept {
     // Transparent SwapChain is not supported
-    flags &= ~backend::SWAP_CHAIN_CONFIG_TRANSPARENT;
+    flags &= ~SWAP_CHAIN_CONFIG_TRANSPARENT;
     NSView* nsView = (__bridge NSView*)nativewindow;
 
     CocoaGLSwapChain* swapChain = new CocoaGLSwapChain( nsView );
@@ -295,6 +295,6 @@ void PlatformCocoaGLImpl::updateOpenGLContext(NSView *nsView, bool resetView,
     }
 }
 
-} // namespace filament
+} // namespace filament::backend
 
 #pragma clang diagnostic pop

filament/backend/src/opengl/platforms/PlatformCocoaTouchGL.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_COCOA_TOUCH_GL_H
-#define TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_COCOA_TOUCH_GL_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_COCOA_TOUCH_GL_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_COCOA_TOUCH_GL_H
 
 #include <stdint.h>
 
@@ -23,16 +23,16 @@
 
 #include "private/backend/OpenGLPlatform.h"
 
-namespace filament {
+namespace filament::backend {
 
 struct PlatformCocoaTouchGLImpl;
 
-class PlatformCocoaTouchGL final : public backend::OpenGLPlatform {
+class PlatformCocoaTouchGL final : public OpenGLPlatform {
 public:
     PlatformCocoaTouchGL();
     ~PlatformCocoaTouchGL() noexcept final;
 
-    backend::Driver* createDriver(void* sharedGLContext) noexcept override;
+    Driver* createDriver(void* sharedGLContext) noexcept override;
     void terminate() noexcept final;
 
     SwapChain* createSwapChain(void* nativewindow, uint64_t& flags) noexcept final;
@@ -44,8 +44,8 @@ public:
             uint32_t& depthbuffer) noexcept final;
     Fence* createFence() noexcept final { return nullptr; }
     void destroyFence(Fence* fence) noexcept final {}
-    backend::FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept final {
-        return backend::FenceStatus::ERROR;
+    FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept final {
+        return FenceStatus::ERROR;
     }
 
     void setPresentationTime(int64_t time) noexcept final override {}
@@ -58,7 +58,7 @@ public:
 
     ExternalTexture* createExternalTextureStorage() noexcept final { return nullptr; }
     void reallocateExternalStorage(ExternalTexture* ets,
-            uint32_t w, uint32_t h, backend::TextureFormat format) noexcept final { }
+            uint32_t w, uint32_t h, TextureFormat format) noexcept final { }
     void destroyExternalTextureStorage(ExternalTexture* ets) noexcept final { }
 
     int getOSVersion() const noexcept final { return 0; }
@@ -73,8 +73,8 @@ private:
     PlatformCocoaTouchGLImpl* pImpl = nullptr;
 };
 
-using ContextManager = filament::PlatformCocoaTouchGL;
+using ContextManager = PlatformCocoaTouchGL;
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_COCOA_TOUCH_GL_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_COCOA_TOUCH_GL_H

filament/backend/src/opengl/platforms/PlatformCocoaTouchGL.mm

@@ -35,7 +35,7 @@
 #include "../OpenGLDriver.h"
 #include "CocoaTouchExternalImage.h"
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 
@@ -103,7 +103,7 @@ void PlatformCocoaTouchGL::terminate() noexcept {
 
 Platform::SwapChain* PlatformCocoaTouchGL::createSwapChain(void* nativewindow, uint64_t& flags) noexcept {
     // Transparent swap chain is not supported
-    flags &= ~backend::SWAP_CHAIN_CONFIG_TRANSPARENT;
+    flags &= ~SWAP_CHAIN_CONFIG_TRANSPARENT;
     return (SwapChain*) nativewindow;
 }
 
@@ -206,4 +206,4 @@ void PlatformCocoaTouchGL::destroyExternalImage(void* texture) noexcept {
     delete p;
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/platforms/PlatformDummyGL.cpp

@@ -16,12 +16,12 @@
 
 #include "PlatformDummyGL.h"
 
-namespace filament {
+namespace filament::backend {
 
 Driver* PlatformDummyGL::createDriver(void* const sharedGLContext) noexcept {
     return nullptr;
 }
 
-} // namespace filament
+} // namespace filament::backend
 
 // ---------------------------------------------------------------------------------------------

filament/backend/src/opengl/platforms/PlatformDummyGL.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_DUMMY_GL_H
-#define TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_DUMMY_GL_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_DUMMY_GL_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_DUMMY_GL_H
 
 #include <stdint.h>
 
@@ -23,12 +23,12 @@
 
 #include "private/backend/OpenGLPlatform.h"
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformDummyGL final : public backend::OpenGLPlatform {
+class PlatformDummyGL final : public OpenGLPlatform {
 public:
 
-    backend::Driver* createDriver(void* const sharedGLContext) noexcept override;
+    Driver* createDriver(void* const sharedGLContext) noexcept override;
     void terminate() noexcept override { }
 
     SwapChain* createSwapChain(void* nativewindow, uint64_t& flags) noexcept final override {
@@ -41,8 +41,8 @@ public:
 
     Fence* createFence() noexcept final override { return nullptr; }
     void destroyFence(Fence* fence) noexcept final override {}
-    backend::FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept final override {
-        return backend::FenceStatus::ERROR;
+    FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept final override {
+        return FenceStatus::ERROR;
     }
 
     Stream* createStream(void* nativeStream) noexcept final override { return nullptr; }
@@ -53,12 +53,12 @@ public:
 
     ExternalTexture* createExternalTextureStorage() noexcept final override { return nullptr; }
     void reallocateExternalStorage(ExternalTexture* ets,
-            uint32_t w, uint32_t h, backend::TextureFormat format) noexcept final override { }
+            uint32_t w, uint32_t h, TextureFormat format) noexcept final override { }
     void destroyExternalTextureStorage(ExternalTexture* ets) noexcept final override { }
 
     int getOSVersion() const noexcept final override { return 0; }
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_DUMMY_GL_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_DUMMY_GL_H

filament/backend/src/opengl/platforms/PlatformEGL.cpp

@@ -28,7 +28,7 @@
 
 using namespace utils;
 
-namespace filament {
+namespace filament::backend {
 using namespace backend;
 
 // The Android NDK doesn't exposes extensions, fake it with eglGetProcAddress
@@ -259,7 +259,7 @@ void PlatformEGL::terminate() noexcept {
 Platform::SwapChain* PlatformEGL::createSwapChain(
         void* nativeWindow, uint64_t& flags) noexcept {
     EGLSurface sur = eglCreateWindowSurface(mEGLDisplay,
-            (flags & backend::SWAP_CHAIN_CONFIG_TRANSPARENT) ?
+            (flags & SWAP_CHAIN_CONFIG_TRANSPARENT) ?
             mEGLTransparentConfig : mEGLConfig,
             (EGLNativeWindowType)nativeWindow, nullptr);
 
@@ -284,7 +284,7 @@ Platform::SwapChain* PlatformEGL::createSwapChain(
     };
 
     EGLSurface sur = eglCreatePbufferSurface(mEGLDisplay,
-                (flags & backend::SWAP_CHAIN_CONFIG_TRANSPARENT) ?
+                (flags & SWAP_CHAIN_CONFIG_TRANSPARENT) ?
                 mEGLTransparentConfig : mEGLConfig, attribs);
 
     if (UTILS_UNLIKELY(sur == EGL_NO_SURFACE)) {
@@ -335,7 +335,7 @@ void PlatformEGL::destroyFence(Platform::Fence* fence) noexcept {
 #endif
 }
 
-backend::FenceStatus PlatformEGL::waitFence(
+FenceStatus PlatformEGL::waitFence(
         Platform::Fence* fence, uint64_t timeout) noexcept {
 #ifdef EGL_KHR_reusable_sync
     EGLSyncKHR sync = (EGLSyncKHR) fence;
@@ -383,6 +383,6 @@ void PlatformEGL::initializeGlExtensions() noexcept {
     ext.OES_EGL_image_external_essl3 = glExtensions.has("GL_OES_EGL_image_external_essl3");
 }
 
-} // namespace filament
+} // namespace filament::backend
 
 // ---------------------------------------------------------------------------------------------

filament/backend/src/opengl/platforms/PlatformEGL.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_EGL_H
-#define TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_EGL_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_EGL_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_EGL_H
 
 #include <stdint.h>
 
@@ -26,14 +26,14 @@
 
 #include "private/backend/OpenGLPlatform.h"
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformEGL : public backend::OpenGLPlatform {
+class PlatformEGL : public OpenGLPlatform {
 public:
 
     PlatformEGL() noexcept;
 
-    backend::Driver* createDriver(void* sharedContext) noexcept override;
+    Driver* createDriver(void* sharedContext) noexcept override;
     void terminate() noexcept override;
 
     SwapChain* createSwapChain(void* nativewindow, uint64_t& flags) noexcept override;
@@ -45,7 +45,7 @@ public:
     bool canCreateFence() noexcept override { return true; }
     Fence* createFence() noexcept override;
     void destroyFence(Fence* fence) noexcept override;
-    backend::FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept override;
+    FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept override;
 
     void createExternalImageTexture(void* texture) noexcept override;
     void destroyExternalImage(void* texture) noexcept override;
@@ -64,7 +64,7 @@ public:
 
     ExternalTexture* createExternalTextureStorage() noexcept override { return nullptr; }
     void reallocateExternalStorage(ExternalTexture* ets,
-            uint32_t w, uint32_t h, backend::TextureFormat format) noexcept override {}
+            uint32_t w, uint32_t h, TextureFormat format) noexcept override {}
     void destroyExternalTextureStorage(ExternalTexture* ets) noexcept override {}
 
 protected:
@@ -87,6 +87,6 @@ protected:
     } ext;
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_EGL_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_EGL_H

filament/backend/src/opengl/platforms/PlatformEGLAndroid.cpp

@@ -45,7 +45,7 @@
 
 using namespace utils;
 
-namespace filament {
+namespace filament::backend {
 using namespace backend;
 
 // The Android NDK doesn't exposes extensions, fake it with eglGetProcAddress
@@ -245,6 +245,6 @@ AcquiredImage PlatformEGLAndroid::transformAcquiredImage(AcquiredImage source) n
     return { eglImage, patchedCallback, closure, source.handler };
 }
 
-} // namespace filament
+} // namespace filament::backend
 
 // ---------------------------------------------------------------------------------------------

filament/backend/src/opengl/platforms/PlatformEGLAndroid.h

@@ -14,12 +14,12 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_EGL_ANDROID_H
-#define TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_EGL_ANDROID_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_EGL_ANDROID_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_EGL_ANDROID_H
 
 #include "PlatformEGL.h"
 
-namespace filament {
+namespace filament::backend {
 
 class ExternalStreamManagerAndroid;
 class ExternalTextureManagerAndroid;
@@ -32,7 +32,7 @@ public:
 
     void terminate() noexcept override;
 
-    backend::Driver* createDriver(void* sharedContext) noexcept final;
+    Driver* createDriver(void* sharedContext) noexcept final;
 
     int getOSVersion() const noexcept final;
 
@@ -46,10 +46,10 @@ public:
 
     ExternalTexture* createExternalTextureStorage() noexcept final;
     void reallocateExternalStorage(ExternalTexture* ets,
-            uint32_t w, uint32_t h, backend::TextureFormat format) noexcept final;
+            uint32_t w, uint32_t h, TextureFormat format) noexcept final;
     void destroyExternalTextureStorage(ExternalTexture* ets) noexcept final;
 
-    backend::AcquiredImage transformAcquiredImage(backend::AcquiredImage source) noexcept final;
+    AcquiredImage transformAcquiredImage(AcquiredImage source) noexcept final;
 
 private:
     int mOSVersion;
@@ -57,6 +57,6 @@ private:
     ExternalTextureManagerAndroid& mExternalTextureManager;
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_EGL_ANDROID_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_EGL_ANDROID_H

filament/backend/src/opengl/platforms/PlatformGLX.cpp

@@ -126,7 +126,7 @@ static bool loadLibraries() {
     return true;
 }
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 
@@ -242,14 +242,14 @@ void PlatformGLX::terminate() noexcept {
 
 Platform::SwapChain* PlatformGLX::createSwapChain(void* nativeWindow, uint64_t& flags) noexcept {
     // Transparent swap chain is not supported
-    flags &= ~backend::SWAP_CHAIN_CONFIG_TRANSPARENT;
+    flags &= ~SWAP_CHAIN_CONFIG_TRANSPARENT;
     return (SwapChain*)nativeWindow;
 }
 
 Platform::SwapChain* PlatformGLX::createSwapChain(
         uint32_t width, uint32_t height, uint64_t& flags) noexcept {
     // Transparent swap chain is not supported
-    flags &= ~backend::SWAP_CHAIN_CONFIG_TRANSPARENT;
+    flags &= ~SWAP_CHAIN_CONFIG_TRANSPARENT;
     int pbufferAttribs[] = {
             GLX_PBUFFER_WIDTH, int(width),
             GLX_PBUFFER_HEIGHT, int(height),
@@ -290,8 +290,8 @@ void PlatformGLX::destroyFence(Fence* fence) noexcept {
     delete fence;
 }
 
-backend::FenceStatus PlatformGLX::waitFence(Fence* fence, uint64_t timeout) noexcept {
-    return backend::FenceStatus::CONDITION_SATISFIED;
+FenceStatus PlatformGLX::waitFence(Fence* fence, uint64_t timeout) noexcept {
+    return FenceStatus::CONDITION_SATISFIED;
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/platforms/PlatformGLX.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_GLX_H
-#define TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_GLX_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_GLX_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_GLX_H
 
 #include <stdint.h>
 
@@ -28,12 +28,12 @@
 
 #include <vector>
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformGLX final : public backend::OpenGLPlatform {
+class PlatformGLX final : public OpenGLPlatform {
 public:
 
-    backend::Driver* createDriver(void* const sharedGLContext) noexcept override;
+    Driver* createDriver(void* const sharedGLContext) noexcept override;
 
     void terminate() noexcept override;
 
@@ -45,7 +45,7 @@ public:
 
     Fence* createFence() noexcept override;
     void destroyFence(Fence* fence) noexcept override;
-    backend::FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept override;
+    FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept override;
 
     void setPresentationTime(int64_t time) noexcept final override {}
 
@@ -57,7 +57,7 @@ public:
 
     ExternalTexture* createExternalTextureStorage() noexcept final override { return nullptr; }
     void reallocateExternalStorage(ExternalTexture* ets,
-            uint32_t w, uint32_t h, backend::TextureFormat format) noexcept final override { }
+            uint32_t w, uint32_t h, TextureFormat format) noexcept final override { }
     void destroyExternalTextureStorage(ExternalTexture* ets) noexcept final override { }
 
     int getOSVersion() const noexcept final override { return 0; }
@@ -70,6 +70,6 @@ private:
     std::vector<GLXPbuffer> mPBuffers;
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_GLX_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_GLX_H

filament/backend/src/opengl/platforms/PlatformWGL.cpp

@@ -66,7 +66,7 @@ void reportLastWindowsError() {
 
 } // namespace
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 
@@ -265,8 +265,8 @@ Platform::Fence* PlatformWGL::createFence() noexcept {
 void PlatformWGL::destroyFence(Fence* fence) noexcept {
 }
 
-backend::FenceStatus PlatformWGL::waitFence(Fence* fence, uint64_t timeout) noexcept {
-    return backend::FenceStatus::ERROR;
+FenceStatus PlatformWGL::waitFence(Fence* fence, uint64_t timeout) noexcept {
+    return FenceStatus::ERROR;
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/platforms/PlatformWGL.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_WGL_H
-#define TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_WGL_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_WGL_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_WGL_H
 
 #include <stdint.h>
 
@@ -26,11 +26,11 @@
 
 #include "private/backend/OpenGLPlatform.h"
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformWGL final : public backend::OpenGLPlatform {
+class PlatformWGL final : public OpenGLPlatform {
 public:
-    backend::Driver* createDriver(void* const sharedGLContext) noexcept override;
+    Driver* createDriver(void* const sharedGLContext) noexcept override;
     void terminate() noexcept override;
 
     SwapChain* createSwapChain(void* nativewindow, uint64_t& flags) noexcept override;
@@ -41,7 +41,7 @@ public:
 
     Fence* createFence() noexcept override;
     void destroyFence(Fence* fence) noexcept override;
-    backend::FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept override;
+    FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept override;
 
     void setPresentationTime(int64_t time) noexcept final override {}
 
@@ -53,7 +53,7 @@ public:
 
     ExternalTexture* createExternalTextureStorage() noexcept final override { return nullptr; }
     void reallocateExternalStorage(ExternalTexture* ets,
-            uint32_t w, uint32_t h, backend::TextureFormat format) noexcept final override { }
+            uint32_t w, uint32_t h, TextureFormat format) noexcept final override { }
     void destroyExternalTextureStorage(ExternalTexture* ets) noexcept final override { }
 
     int getOSVersion() const noexcept final override { return 0; }
@@ -65,6 +65,6 @@ private:
     PIXELFORMATDESCRIPTOR mPfd = {};
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_GLX_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_GLX_H

filament/backend/src/opengl/platforms/PlatformWebGL.cpp

@@ -17,7 +17,7 @@
 #include "PlatformWebGL.h"
 #include "../OpenGLDriverFactory.h"
 
-namespace filament {
+namespace filament::backend {
 
 using namespace backend;
 
@@ -58,8 +58,8 @@ void PlatformWebGL::destroyFence(Fence* fence) noexcept {
     delete fence;
 }
 
-backend::FenceStatus PlatformWebGL::waitFence(Fence* fence, uint64_t timeout) noexcept {
-    return backend::FenceStatus::CONDITION_SATISFIED;
+FenceStatus PlatformWebGL::waitFence(Fence* fence, uint64_t timeout) noexcept {
+    return FenceStatus::CONDITION_SATISFIED;
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/opengl/platforms/PlatformWebGL.h

@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_WEBGL_H
-#define TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_WEBGL_H
+#ifndef TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_WEBGL_H
+#define TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_WEBGL_H
 
 #include <stdint.h>
 
@@ -26,12 +26,12 @@
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformWebGL final : public backend::OpenGLPlatform {
+class PlatformWebGL final : public OpenGLPlatform {
 public:
 
-    backend::Driver* createDriver(void* const sharedGLContext) noexcept override;
+    Driver* createDriver(void* const sharedGLContext) noexcept override;
     void terminate() noexcept override;
 
     SwapChain* createSwapChain(void* nativewindow, uint64_t& flags) noexcept final override;
@@ -42,7 +42,7 @@ public:
 
     Fence* createFence() noexcept final override;
     void destroyFence(Fence* fence) noexcept final override;
-    backend::FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept final override;
+    FenceStatus waitFence(Fence* fence, uint64_t timeout) noexcept final override;
 
     void setPresentationTime(int64_t time) noexcept final override {}
 
@@ -54,12 +54,12 @@ public:
 
     ExternalTexture* createExternalTextureStorage() noexcept final override { return nullptr; }
     void reallocateExternalStorage(ExternalTexture* ets,
-            uint32_t w, uint32_t h, backend::TextureFormat format) noexcept final override { }
+            uint32_t w, uint32_t h, TextureFormat format) noexcept final override { }
     void destroyExternalTextureStorage(ExternalTexture* ets) noexcept final override { }
 
     int getOSVersion() const noexcept final override { return 0; }
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_OPENGL_PLATFORM_WEBGL_H
+#endif // TNT_FILAMENT_BACKEND_OPENGL_OPENGL_PLATFORM_WEBGL_H

filament/backend/src/ostream.cpp

@@ -28,7 +28,7 @@ using namespace utils;
 
 // ------------------------------------------------------------------------------------------------
 // Stream operators for all types in DriverEnums.h
-// (These must live outside of the filament namespace)
+// (These must live outside the filament namespace)
 // ------------------------------------------------------------------------------------------------
 
 #if !defined(NDEBUG)
@@ -497,6 +497,18 @@ io::ostream& operator<<(io::ostream& out, MRT const& mrt) {
     return out;
 }
 
+io::ostream& operator<<(io::ostream& stream, ShaderStageFlags stageFlags) {
+    unsigned int v = +stageFlags.vertex + 2u * +stageFlags.fragment;
+    const char* str = nullptr;
+    switch (v & 3) {
+        case 0: str = "{ }"; break;
+        case 1: str = "{ vertex }"; break;
+        case 2: str = "{ fragment }"; break;
+        case 3: str = "{ vertex | fragment }"; break;
+    }
+    return stream << str;
+}
+
 #undef CASE
 
 #endif // !NDEBUG

filament/backend/src/vulkan/PlatformVkAndroid.cpp

@@ -27,9 +27,7 @@
 
 using namespace bluevk;
 
-namespace filament {
-
-using namespace backend;
+namespace filament::backend {
 
 Driver* PlatformVkAndroid::createDriver(void* const sharedContext) noexcept {
     ASSERT_PRECONDITION(sharedContext == nullptr, "Vulkan does not support shared contexts.");
@@ -50,4 +48,4 @@ void* PlatformVkAndroid::createVkSurfaceKHR(void* nativeWindow, void* vkinstance
     return (void*) surface;
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/vulkan/PlatformVkAndroid.h

@@ -14,26 +14,26 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_VULKAN_PLATFORM_VK_ANDROID_H
-#define TNT_FILAMENT_DRIVER_VULKAN_PLATFORM_VK_ANDROID_H
+#ifndef TNT_FILAMENT_BACKEND_VULKAN_PLATFORM_VK_ANDROID_H
+#define TNT_FILAMENT_BACKEND_VULKAN_PLATFORM_VK_ANDROID_H
 
 #include <stdint.h>
 
 #include <backend/DriverEnums.h>
 #include "VulkanPlatform.h"
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformVkAndroid final : public backend::VulkanPlatform {
+class PlatformVkAndroid final : public VulkanPlatform {
 public:
 
-    backend::Driver* createDriver(void* const sharedContext) noexcept override;
+    Driver* createDriver(void* const sharedContext) noexcept override;
 
     void* createVkSurfaceKHR(void* nativeWindow, void* instance, uint64_t flags) noexcept override;
 
     int getOSVersion() const noexcept override { return 0; }
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_VULKAN_PLATFORM_VK_ANDROID_H
+#endif // TNT_FILAMENT_BACKEND_VULKAN_PLATFORM_VK_ANDROID_H

filament/backend/src/vulkan/PlatformVkCocoa.h

@@ -14,23 +14,23 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_VULKAN_PLATFORM_VK_COCOA_H
-#define TNT_FILAMENT_DRIVER_VULKAN_PLATFORM_VK_COCOA_H
+#ifndef TNT_FILAMENT_BACKEND_VULKAN_PLATFORM_VK_COCOA_H
+#define TNT_FILAMENT_BACKEND_VULKAN_PLATFORM_VK_COCOA_H
 
 #include <stdint.h>
 
 #include <backend/DriverEnums.h>
 #include "VulkanPlatform.h"
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformVkCocoa final : public backend::VulkanPlatform {
+class PlatformVkCocoa final : public VulkanPlatform {
 public:
-    backend::Driver* createDriver(void* sharedContext) noexcept override;
+    Driver* createDriver(void* sharedContext) noexcept override;
     void* createVkSurfaceKHR(void* nativeWindow, void* instance, uint64_t flags) noexcept override;
     int getOSVersion() const noexcept override { return 0; }
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_VULKAN_PLATFORM_VK_COCOA_H
+#endif // TNT_FILAMENT_BACKEND_VULKAN_PLATFORM_VK_COCOA_H

filament/backend/src/vulkan/PlatformVkCocoa.mm

@@ -32,9 +32,7 @@
 
 using namespace bluevk;
 
-namespace filament {
-
-using namespace backend;
+namespace filament::backend {
 
 Driver* PlatformVkCocoa::createDriver(void* sharedContext) noexcept {
     ASSERT_PRECONDITION(sharedContext == nullptr, "Vulkan does not support shared contexts.");
@@ -61,4 +59,4 @@ void* PlatformVkCocoa::createVkSurfaceKHR(void* nativeWindow, void* instance, ui
     return surface;
 }
 
-} // namespace filament
+} // namespace filament::backend

filament/backend/src/vulkan/PlatformVkCocoaTouch.h

@@ -14,23 +14,23 @@
  * limitations under the License.
  */
 
-#ifndef TNT_FILAMENT_DRIVER_VULKAN_PLATFORM_VK_COCOA_TOUCH_H
-#define TNT_FILAMENT_DRIVER_VULKAN_PLATFORM_VK_COCOA_TOUCH_H
+#ifndef TNT_FILAMENT_BACKEND_VULKAN_PLATFORM_VK_COCOA_TOUCH_H
+#define TNT_FILAMENT_BACKEND_VULKAN_PLATFORM_VK_COCOA_TOUCH_H
 
 #include <stdint.h>
 
 #include <backend/DriverEnums.h>
 #include "VulkanPlatform.h"
 
-namespace filament {
+namespace filament::backend {
 
-class PlatformVkCocoaTouch final : public backend::VulkanPlatform {
+class PlatformVkCocoaTouch final : public VulkanPlatform {
 public:
-    backend::Driver* createDriver(void* const sharedContext) noexcept override;
+    Driver* createDriver(void* const sharedContext) noexcept override;
     void* createVkSurfaceKHR(void* nativeWindow, void* instance, uint64_t flags) noexcept override;
     int getOSVersion() const noexcept override { return 0; }
 };
 
-} // namespace filament
+} // namespace filament::backend
 
-#endif // TNT_FILAMENT_DRIVER_VULKAN_CONTEXTMANAGERVKCOCOATOUCH_H
+#endif // TNT_FILAMENT_BACKEND_VULKAN_CONTEXTMANAGERVKCOCOATOUCH_H