Fix missing dep in CompressedStringChunk (#9534)

This reverts commit f5071b2aae.

.clang-format

@@ -65,4 +65,6 @@ SpacesInParentheses: false
 SpacesInSquareBrackets: false
 TabWidth: 4
 UseTab: Never
-PackConstructorInitializers: Never
+PackConstructorInitializers: Never
+ConstructorInitializerIndentWidth: 8
+IndentWrappedFunctionNames: true

.github/actions/get-commit-msg/action.yml

@@ -1,43 +1,53 @@
+# This action retrieves the latest commit message from a push or pull_request event
+# and makes it available as an output variable named 'msg'.
 name: 'Get commit message'
 outputs:
   msg:
     value: ${{ steps.action_output.outputs.msg }}
+  hash:
+    value: ${{ steps.action_output.outputs.hash }}
 runs:
   using: "composite"
   steps:
     - name: Find commit message (on push)
       if: github.event_name == 'push'
       shell: bash
+      env:
+        COMMIT_MESSAGE: ${{ github.event.head_commit.message }}
       run: |
         AUTHOR_NAME="${{ github.event.head_commit.author.name }}"
         AUTHOR_EMAIL="${{ github.event.head_commit.author.email }}"
         TSTAMP="${{ github.event.head_commit.timestamp }}"
-        echo "commit ${{ github.event.head_commit.id }}" >> /tmp/commit_msg.txt
+        HASH="${{ github.event.head_commit.id }}"
+        echo "commit $HASH" >> /tmp/commit_msg.txt
         echo "Author: ${AUTHOR_NAME}<${AUTHOR_EMAIL}>" >> /tmp/commit_msg.txt
         echo "Date: ${TSTAMP}" >> /tmp/commit_msg.txt
         echo "" >> /tmp/commit_msg.txt
-        echo "${{ github.event.head_commit.message }}" >> /tmp/commit_msg.txt
+        echo "$COMMIT_MESSAGE" >> /tmp/commit_msg.txt
+        echo "$HASH" > /tmp/commit_hash.txt
     - name: Find commit message (PR)
       shell: bash
       id: checkout_code
       if: github.event_name == 'pull_request'
       run: |
-        echo "+++++ head commit message +++++"
-        echo "$(git log -1 --no-merges)"
-        echo "+++++++++++++++++++++++++++++++"
-        echo "hash=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"
-        git checkout ${{ github.event.pull_request.head.sha }}
-        echo "$(git log -1 --no-merges)" >> /tmp/commit_msg.txt
+        BEFORE_HASH=$(git rev-parse HEAD)
+        echo "hash=$BEFORE_HASH" >> "$GITHUB_OUTPUT"
+        # Next we will checkout the actual head (not the merge commits) of the PR
+        AFTER_HASH="${{ github.event.pull_request.head.sha }}"
+        git checkout $AFTER_HASH
+        COMMIT_MESSAGE=$(git log -1 --no-merges)
+        echo "$COMMIT_MESSAGE" > /tmp/commit_msg.txt
+        echo "$AFTER_HASH" > /tmp/commit_hash.txt
     - shell: bash
       id: action_output
       run: |
+        # Get the commit message
         DELIMITER="EOF_FILE_CONTENT_$(date +%s)" # Using timestamp to make it more unique
         echo "msg<<$DELIMITER" >> "$GITHUB_OUTPUT"
         cat /tmp/commit_msg.txt >> "$GITHUB_OUTPUT"
         echo "$DELIMITER" >> "$GITHUB_OUTPUT"
-        echo "----- got commit message ---"
-        cat /tmp/commit_msg.txt
-        echo "----------------------------"
+        # Get the commit hash
+        echo "hash=$(cat /tmp/commit_hash.txt)" >> "$GITHUB_OUTPUT"
     - name: Cleanup Find commit message (PR)
       shell: bash
       if: github.event_name == 'pull_request'

.github/actions/mac-prereq/action.yml

@@ -15,7 +15,7 @@ runs:
       uses: actions/cache@v4 # Use a specific version
       with:
         path: ~/Library/Caches/Homebrew
-        key: ${{ runner.os }}-brew-20250424
+        key: ${{ runner.os }}-brew-20251211
     - name: Install Mac Prerequisites
       shell: bash
       run: |

.github/workflows/android-continuous.yml

@@ -12,7 +12,7 @@ jobs:
     name: build-android
     # We intentially use a larger runner here to enable larger disk space
     # (standard linux runner will fail on disk space and faster build time).
-    runs-on: 'ubuntu-24.04-32core'
+    runs-on: 'ubuntu-24.04-16core'
 
     steps:
       - uses: actions/checkout@v4.1.6

.github/workflows/postsubmit.yml

@@ -21,9 +21,10 @@ jobs:
       - name: Run update script
         env:
           GH_TOKEN: ${{ secrets.FILAMENTBOT_TOKEN }}
+          COMMIT_MESSAGE: ${{ steps.get_commit_msg.outputs.msg }}
         run: |
-          GOLDEN_BRANCH=$(echo "${{ steps.get_commit_msg.outputs.msg }}" | python3 test/renderdiff/src/commit_msg.py)
-          COMMIT_HASH=$(echo "${{ steps.get_commit_msg.outputs.msg }}" | head -n 1 | sed "s/commit //g")
+          GOLDEN_BRANCH=$(echo "${COMMIT_MESSAGE}" | python3 test/renderdiff/src/commit_msg.py)
+          COMMIT_HASH="${{ steps.get_commit_msg.outputs.hash }}"
           if [[ "${GOLDEN_BRANCH}" != "main" ]]; then
               git config --global user.email "filament.bot@gmail.com"
               git config --global user.name "Filament Bot"
@@ -51,7 +52,7 @@ jobs:
           GH_TOKEN: ${{ secrets.FILAMENTBOT_TOKEN }}
         run: |
           bash docs_src/build/install_mdbook.sh && source ~/.bashrc
-          COMMIT_HASH=$(echo "${{ steps.get_commit_msg.outputs.msg }}" | head -n 1 | sed "s/commit //g")
+          COMMIT_HASH="${{ steps.get_commit_msg.outputs.hash }}"
           git config --global user.email "filament.bot@gmail.com"
           git config --global user.name "Filament Bot"
           git config --global credential.helper cache

.github/workflows/presubmit.yml

@@ -26,7 +26,7 @@ jobs:
 
   build-desktop-linux:
     name: build-linux
-    runs-on: ubuntu-22.04-16core
+    runs-on: 'ubuntu-24.04-16core'
     steps:
       - uses: actions/checkout@v4.1.6
         with:
@@ -108,8 +108,7 @@ jobs:
         uses: ./.github/actions/get-commit-msg
       - name: Check for manual edits to /docs
         run: |
-          COMMIT_ID=$(echo "${{ steps.get_commit_msg.outputs.msg }}" | head -n 1 | sed "s/commit //g")
-          bash docs_src/build/presubmit_check.sh ${COMMIT_ID}
+          bash docs_src/build/presubmit_check.sh ${{ steps.get_commit_msg.outputs.hash }}
 
   test-renderdiff:
     name: test-renderdiff
@@ -121,7 +120,7 @@ jobs:
       - uses: ./.github/actions/mac-prereq
       - uses: ./.github/actions/get-gltf-assets
       - uses: ./.github/actions/get-mesa
-      - uses: ./.github/actions/get-vulkan-sdk      
+      - uses: ./.github/actions/get-vulkan-sdk
       - id: get_commit_msg
         uses: ./.github/actions/get-commit-msg
       - name: Prerequisites
@@ -132,19 +131,20 @@ jobs:
         shell: bash
       - name: Render and compare
         id: render_compare
+        env:
+          COMMIT_MESSAGE: ${{ steps.get_commit_msg.outputs.msg }}
         run: |
-          ls ./gltf/Models
           TEST_DIR=test/renderdiff
           source ${TEST_DIR}/src/preamble.sh
-          start_
-          GOLDEN_BRANCH=$(echo "${{ steps.get_commit_msg.outputs.msg }}" | python3 ${TEST_DIR}/src/commit_msg.py)
-          bash ${TEST_DIR}/generate.sh && \
-              python3 ${TEST_DIR}/src/golden_manager.py \
+          set -eux
+          GOLDEN_BRANCH=$(echo "${COMMIT_MESSAGE}" | python3 ${TEST_DIR}/src/commit_msg.py)
+          bash ${TEST_DIR}/generate.sh
+          python3 ${TEST_DIR}/src/golden_manager.py \
                   --branch=${GOLDEN_BRANCH} \
                   --output=${GOLDEN_OUTPUT_DIR}
 
-          # Note that we need to upload the output even if comparison fails, so we undo `set -ex`
-          end_
+          # Note that we need to upload the output even if comparison fails, so we undo `set -eux`
+          set +eux
 
           python3 ${TEST_DIR}/src/compare.py \
               --src=${GOLDEN_OUTPUT_DIR} \
@@ -157,6 +157,7 @@ jobs:
              cat compare_output.txt >> "$GITHUB_OUTPUT"
              echo "$DELIMITER" >> "$GITHUB_OUTPUT"
           fi
+        shell: bash
       - uses: actions/upload-artifact@v4
         with:
           name: presubmit-renderdiff-result
@@ -171,14 +172,14 @@ jobs:
 
   validate-wgsl-webgpu:
     name: validate-wgsl-webgpu
-    runs-on: 'ubuntu-24.04-8core'
+    runs-on: 'ubuntu-24.04-16core'
     steps:
       - uses: actions/checkout@v4.1.6
         with:
           fetch-depth: 0
       - uses: ./.github/actions/linux-prereq
       - name: Run build script
-        run: ./build.sh -W debug test_filamat filament
+        run: ./build.sh -W debug test_filamat filament gltf_viewer
       - name: Run test
         run: ./out/cmake-debug/libs/filamat/test_filamat --gtest_filter=MaterialCompiler.Wgsl*
 
@@ -202,3 +203,23 @@ jobs:
           ./build.sh -p desktop debug gltf_viewer
       - name: Run test
         run: bash test/code-correctness/test.sh
+
+  test-backend:
+    name: test-backend
+    runs-on: macos-14-xlarge
+    steps:
+      - uses: actions/checkout@v4.1.6
+        with:
+          fetch-depth: 0
+      - uses: ./.github/actions/mac-prereq
+      - uses: ./.github/actions/get-mesa
+      - uses: ./.github/actions/get-vulkan-sdk
+      - name: Prerequisites
+        run: |
+          # Must have at least clang-16 for a webgpu/dawn build.
+          sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+        shell: bash
+      - name: Run backend tests
+        shell: bash
+        run: |
+          bash test/backend/test.sh

.github/workflows/release.yml

@@ -31,7 +31,7 @@ on:
 jobs:
   build-linux:
     name: build-linux
-    runs-on: ubuntu-22.04-32core
+    runs-on: 'ubuntu-24.04-16core'
     if: github.event_name == 'release' || github.event.inputs.platform == 'desktop'
 
     steps:

.gitignore

@@ -18,3 +18,9 @@ test*.json
 results
 /compile_commands.json
 /.cache
+
+# For /test/renderdiff dependencies
+/mesa
+/gltf
+/filament-assets
+/venv

BUILDING.md

@@ -62,6 +62,11 @@ force a clean build by adding the `-c` flag in that case.
 To install the libraries and executables in `out/debug/` and `out/release/`, add the `-i` flag.
 The script offers more features described by executing `build.sh -h`.
 
+For more specialized options, please also consider the following pages:
+ - `-d`: [`matdbg`](https://google.github.io/filament/dup/matdbg.html)
+ - `-t`: [`fgviewer`](https://google.github.io/filament/dup/fgviewer.html)
+ - `-b` and `-y`: [ASAN/UBSAN builds](https://google.github.io/filament/notes/asan_ubsan.html)
+
 ### Filament-specific CMake Options
 
 The following CMake options are boolean options specific to Filament:
@@ -237,6 +242,12 @@ foremost for `arm64-v8a`.
 
 To build Android on Windows machines, see [android/Windows.md](android/Windows.md).
 
+#### Important: SDK location
+
+Either ensure your `ANDROID_HOME` environment variable is set or make sure the root project
+contains a `local.properties` file with the `sdk.dir` property pointing to your installation of
+the Android SDK.
+
 #### Easy Android build
 
 The easiest way to build Filament for Android is to use `build.sh` and the
@@ -246,8 +257,45 @@ The easiest way to build Filament for Android is to use `build.sh` and the
 ./build.sh -p android release
 ```
 
+To build a sample (such as `android/samples/sample-hello-triangle`) for an ARM 64-bit phone, you would run
+```shell
+./build.sh -p android -q arm64-v8a -k sample-hello-triangle release
+```
+
+The output APK can be found in `android/samples/sample-hello-triangle/build/outputs/apk/release/sample-hello-triangle-release-unsigned.apk`
+
 Run `build.sh -h` for more information.
 
+#### Android Studio
+
+You must use the latest stable release of Android Studio.
+
+The Android build of filament is separated into java/kotlin client APIs, a layer of jni bindings
+that bridges java/kotlin with native code, and Filament and other component code that have been compiled
+into architecture-specific libraries. Our default Android Studio gradle setup can compile java/kotlin and
+the jni bindings for you, but it will treat the filament libraries as already compiled and present on
+the system.
+
+Therefore, before compiling the sample app or any other targets, you must
+make sure that the native filament libraries have been compiled and are located at a prescribed location
+so that the jni bindings can link against them. You can do so by using the easy build script
+
+```shell
+./build.sh -p android release -q arm64-v8a
+```
+
+Note that the above step will also install host machine tools into prescribed locations.  These tools are
+required for compiling Filament assets such as materials and environment maps.
+
+Now we are ready to compile the apps.  To open the project, point Studio to the `android` folder.
+After opening the project and syncing with Gradle, select the sample of your choice
+using the drop-down widget in the toolbar. Additionally, you will need to select a deployment target.
+By doing so, Android Studio will automatically try to compile the app only for that specific
+device's architecture. So if you are targeting a new Pixel phone, make sure that the step above
+(compiling the library) is targeting ARM 64-bit (`-q arm64-v8a` ), and if you are running the app on
+an emulator on a Linux machine with an x86 64-bit chipset, you would indicate (`-q x86_64`) in the above step.
+
+
 #### Manual builds
 
 Invoke CMake in a build directory of your choice, inside of filament's directory. The commands
@@ -391,7 +439,7 @@ Alternatively, if you have node installed you can use the
 [live-server](https://www.npmjs.com/package/live-server) package, which automatically refreshes the
 web page when it detects a change.
 
-Each sample app has its own handwritten html file. Additionally the server folder contains assets
+Each sample app has its own handwritten html file. Additionally, the server folder contains assets
 such as meshes, textures, and materials.
 
 ## Running the native samples

CMakeLists.txt

@@ -56,6 +56,10 @@ option(FILAMENT_ENABLE_FGVIEWER "Enable the frame graph viewer" OFF)
 
 option(FILAMENT_USE_ABSEIL_LOGGING "Use Abseil to log, may increase binary size" OFF)
 
+option(FILAMENT_ENABLE_EXPERIMENTAL_GCC_SUPPORT "Enable GCC support (unsupported)" OFF)
+
+option(FILAMENT_SUPPORTS_WEBP_TEXTURES "Enable webp texture support for Filament (builds libwebp when ON)" OFF)
+
 # This is to disable GTAO for the short-term while we investigate a way to better manage size increases.
 # On the regular filament build (where size is of less concern), we enable GTAO by default.
 option(FILAMENT_DISABLE_GTAO "Disable GTAO" OFF)
@@ -295,15 +299,10 @@ set(TOOLS ${CMAKE_CURRENT_SOURCE_DIR}/tools)
 # ==================================================================================================
 set(MIN_CLANG_VERSION "6.0")
 
-if (CMAKE_C_COMPILER_ID MATCHES "Clang")
-    if (CMAKE_C_COMPILER_VERSION VERSION_LESS MIN_CLANG_VERSION)
-        message(FATAL_ERROR "Detected C compiler Clang ${CMAKE_C_COMPILER_VERSION} < ${MIN_CLANG_VERSION}")
-    endif()
-elseif (NOT MSVC)
-    message(FATAL_ERROR "Detected C compiler ${CMAKE_C_COMPILER_ID} is unsupported")
-endif()
-
-if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+set(FILAMENT_USING_GCC OFF)
+if (CMAKE_C_COMPILER_ID MATCHES "GNU" AND FILAMENT_ENABLE_EXPERIMENTAL_GCC_SUPPORT)
+    set(FILAMENT_USING_GCC ON)
+elseif (CMAKE_C_COMPILER_ID MATCHES "Clang")
     if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS MIN_CLANG_VERSION)
         message(FATAL_ERROR "Detected CXX compiler Clang ${CMAKE_CXX_COMPILER_VERSION} < ${MIN_CLANG_VERSION}")
     endif()
@@ -344,14 +343,18 @@ if (MSVC)
     set(CXX_STANDARD "/std:c++latest")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_STANDARD} /W0 /Zc:__cplusplus")
 else()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_STANDARD} -fstrict-aliasing -Wno-unknown-pragmas -Wno-unused-function -Wno-deprecated-declarations")
+    if(FILAMENT_USING_GCC)
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_STANDARD} -Wno-changes-meaning -Wno-return-type -Wno-attributes -Wno-unknown-pragmas -Wno-class-memaccess -Wno-multichar -Wno-deprecated-declarations -Wno-subobject-linkage -Wno-invalid-constexpr")
+    else()
+      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_STANDARD} -fstrict-aliasing -Wno-unknown-pragmas -Wno-unused-function -Wno-deprecated-declarations")
+    endif()
     if (APPLE)
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-nullability-extension")
     endif()
 endif()
 
 if (FILAMENT_USE_EXTERNAL_GLES3)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DUSE_EXTERNAL_GLES3")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DFILAMENT_USE_EXTERNAL_GLES3")
 endif()
 
 if (FILAMENT_SUPPORTS_EGL_ON_LINUX)
@@ -365,10 +368,14 @@ endif()
 if (LINUX)
     option(USE_STATIC_LIBCXX "Link against the static runtime libraries." ON)
     if (${USE_STATIC_LIBCXX})
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
-        link_libraries("-static-libgcc -static-libstdc++")
-        link_libraries(libc++.a)
-        link_libraries(libc++abi.a)
+        if (FILAMENT_USING_GCC)
+            link_libraries("-static-libgcc -static-libstdc++")
+        else ()
+            set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
+            link_libraries("-static-libgcc -static-libstdc++")
+            link_libraries(libc++.a)
+            link_libraries(libc++abi.a)
+        endif()
     endif()
 
     # Only linux, clang doesn't want to use a shared library that is not PIC.
@@ -393,8 +400,8 @@ if (MSVC)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_DEPRECATE")
 endif()
 
-# Add colors to ninja builds
-if (UNIX AND CMAKE_GENERATOR STREQUAL "Ninja")
+# Add colors to ninja builds (when not using gcc)
+if (UNIX AND CMAKE_GENERATOR STREQUAL "Ninja" AND NOT FILAMENT_USING_GCC)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fcolor-diagnostics")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fcolor-diagnostics")
 endif()
@@ -748,12 +755,61 @@ function(combine_static_libs TARGET OUTPUT DEPS)
 endfunction()
 
 # ==================================================================================================
-# Configuration for CMAKE_CROSSCOMPILING.
+# Configuration importing/exporting prebuilt "/tools" executables
 # ==================================================================================================
+
+# In certain cases, we want the ability to separate the build type/flags (release, debug) of tools
+# (matc, resgen, etc...) from filament.  Cross compilation is one such case (e.g. building material
+# with matc running on host while building filament for Android) [1]. Another example is when client
+# wants to enable ASAN for filament but not the tool [2].
+#
+# Here are the varibles that are used to determine behavior is such flows:
+#   - CMAKE_CROSSCOMPILING : Set by cmake to indicate the build's target platform is different
+#     from the host platform.
+#   - IMPORT_EXECUTABLES_DIR : This is the directory containing the /ImportExecutables-type.cmake
+#     which are then included in other CMakeLists.txt to enable finding targets that have been
+#     prebuilt. This is set by the client in their `cmake` invocation.
+#   - IMPORT_EXECUTABLES : Path to a file to for 1) exporting the prebuilt targets or 2)
+#     importing a previously exported targets. (Used internally and should not be set by client).
+#   - FILAMENT_EXPORT_PREBUILT_EXECUTABLES_DIR : A path set by the client to indicate that
+#     they wish to export the tools as prebuilts, and the corresponding targets will be recorded
+#     in a cmake file (i.e IMPORT_EXECUTABLES). IMPORT_EXECUTABLES will be set relative to the the
+#     given path. This will set FILAMENT_EXPORT_PREBUILT_EXECUTABLES=ON.
+#   - FILAMENT_IMPORT_PREBUILT_EXECUTABLES_DIR : A path set by the client to indicate that they wish
+#     to import the tools as prebuilts from a .cmake file. The location (IMPORT_EXECUTABLES) of the
+#     file is relative to the path given. This will set FILAMENT_IMPORT_PREBUILT_EXECUTABLES=ON.
+#   - IMPORT_PREBUILT_EXECUTABLES and EXPORT_PREBUILT_EXECUTABLES are internal booleans set to
+#     ON based on the prescence of FILAMENT_IMPORT_PREBUILT_EXECUTABLES_DIR and
+#     FILAMENT_EXPORT_PREBUILT_EXECUTABLES_DIR.
+#
+# In conclusion, for cases
+#   - [1] (crosscompiling), the client must set IMPORT_EXECUTABLES_DIR for both when they are building
+#     the tools and when they are building the target-platform filament.
+#   - [2] (all other instances), the client must set FILAMENT_EXPORT_PREBUILT_EXECUTABLES_DIR in
+#     the prebuilt exporting step, and set FILAMENT_IMPORT_PREBUILT_EXECUTABLES_DIR in the importing
+#     step.
+
+# TODO: Fold the cross compilation case into the more general FILAMENT_IMPORT/EXPORT variables.
+
+if (FILAMENT_EXPORT_PREBUILT_EXECUTABLES_DIR)
+   set(FILAMENT_EXPORT_PREBUILT_EXECUTABLES ON)
+   set(IMPORT_EXECUTABLES_DIR ${FILAMENT_EXPORT_PREBUILT_EXECUTABLES_DIR})
+endif()
+
+if (FILAMENT_IMPORT_PREBUILT_EXECUTABLES_DIR)
+   set(FILAMENT_IMPORT_PREBUILT_EXECUTABLES ON)
+   set(IMPORT_EXECUTABLES_DIR ${FILAMENT_IMPORT_PREBUILT_EXECUTABLES_DIR})
+endif()
+
 if (WEBGL)
     set(IMPORT_EXECUTABLES ${FILAMENT}/${IMPORT_EXECUTABLES_DIR}/ImportExecutables-Release.cmake)
 else()
-    set(IMPORT_EXECUTABLES ${FILAMENT}/${IMPORT_EXECUTABLES_DIR}/ImportExecutables-${CMAKE_BUILD_TYPE}.cmake)
+    if (FILAMENT_EXPORT_PREBUILT_EXECUTABLES OR FILAMENT_IMPORT_PREBUILT_EXECUTABLES)
+        set(IMPORT_EXECUTABLES_BUILD_TYPE Prebuilt)
+    else()
+        set(IMPORT_EXECUTABLES_BUILD_TYPE ${CMAKE_BUILD_TYPE})
+    endif()
+    set(IMPORT_EXECUTABLES ${FILAMENT}/${IMPORT_EXECUTABLES_DIR}/ImportExecutables-${IMPORT_EXECUTABLES_BUILD_TYPE}.cmake)
 endif()
 
 # ==================================================================================================
@@ -816,7 +872,9 @@ add_subdirectory(${LIBRARIES}/utils)
 add_subdirectory(${LIBRARIES}/viewer)
 add_subdirectory(${FILAMENT}/shaders)
 add_subdirectory(${EXTERNAL}/abseil/tnt)
-add_subdirectory(${EXTERNAL}/basisu/tnt)
+# Add zstd before basisu to force it to use the external zstd target,
+# preventing a duplicate symbol conflict with its bundled version.
+add_subdirectory(${EXTERNAL}/zstd/tnt)
 add_subdirectory(${EXTERNAL}/civetweb/tnt)
 add_subdirectory(${EXTERNAL}/imgui/tnt)
 add_subdirectory(${EXTERNAL}/robin-map/tnt)
@@ -830,7 +888,8 @@ add_subdirectory(${EXTERNAL}/jsmn/tnt)
 add_subdirectory(${EXTERNAL}/stb/tnt)
 add_subdirectory(${EXTERNAL}/getopt)
 add_subdirectory(${EXTERNAL}/perfetto/tnt)
-add_subdirectory(${EXTERNAL}/zstd/tnt)
+add_subdirectory(${EXTERNAL}/basisu/tnt)
+
 
 # Note that this has to be placed after mikktspace in order for combine_static_libs to work.
 add_subdirectory(${LIBRARIES}/geometry)
@@ -854,6 +913,11 @@ if (FILAMENT_ENABLE_FGVIEWER)
     add_subdirectory(${LIBRARIES}/fgviewer)
 endif()
 
+if (FILAMENT_SUPPORTS_WEBP_TEXTURES)
+    add_subdirectory(${EXTERNAL}/libwebp/tnt)
+    add_definitions(-DFILAMENT_SUPPORTS_WEBP_TEXTURES)
+endif()
+
 if (FILAMENT_SUPPORTS_VULKAN)
     add_subdirectory(${LIBRARIES}/bluevk)
     add_subdirectory(${EXTERNAL}/vkmemalloc/tnt)
@@ -912,6 +976,6 @@ if (IS_HOST_PLATFORM)
 endif()
 
 # Generate exported executables for cross-compiled builds (Android, WebGL, and iOS)
-if (NOT CMAKE_CROSSCOMPILING)
+if ((NOT CMAKE_CROSSCOMPILING AND NOT FILAMENT_IMPORT_PREBUILT_EXECUTABLES) OR FILAMENT_EXPORT_PREBUILT_EXECUTABLES)
     export(TARGETS matc cmgen filamesh mipgen resgen uberz glslminifier FILE ${IMPORT_EXECUTABLES})
 endif()

CODE_STYLE.md

@@ -20,7 +20,7 @@ The guiding principles of the filament code style and code formatting can be res
 - class access modifiers are not indented
 - last line of `.cpp` or `.h` file must be an empty line
 
-```
+```c++
 for (int i = 0; i < max; i++) {
 }
 
@@ -73,12 +73,24 @@ src/data.inc
 - `public` class attributes *are not* prefixed
 - class attributes and methods are lower camelcase
 
-```
+```c++
 extern int gGlobalWarming;
 
 class FooBar {
 public:
-    void methodName();
+    FooBar(int attributeName, int sizeInBytes)
+            : mAttributeName(attributeName),
+              sizeInBytes(sizeInBytes) {}
+
+    void reallyLongMethodNameWithLotsOfArguments(bool argument1,
+            int someSecondArgument, int bestArgument) {
+        std::pair<bool, int> pair = {
+            argument1,
+            argument2,
+        };
+        // etc
+    }
+
     int sizeInBytes;
 private:
     int mAttributeName;
@@ -97,7 +109,7 @@ private:
 - always include the copyright notice at the top of every file
 - make sure the date is correct
 
-```
+```c++
 /*
  * Copyright (C) 2018 The Android Open Source Project
  *
@@ -139,7 +151,7 @@ conversely containers and algorithms are not allowed. There are exceptions such
 
 *Sorting the headers is important to help catching missing `#include` directives.*
 
-```
+```c++
 /*
  * Copyright (C) 2018 The Android Open Source Project
  *
@@ -183,7 +195,7 @@ conversely containers and algorithms are not allowed. There are exceptions such
 ### Misc
 
 - Use `auto` only when the type appears on the same line or with iterators and lambdas.
-```
+```c++
 auto foo = new Foo();
 for (auto& i : collection) { }
 ```

NEW_RELEASE_NOTES.md

@@ -1,7 +1,6 @@
 # Filament Release Notes log
 
 **If you are merging a PR into main**: please add the release note below, under the *Release notes
-We are chaning the way Vulkan buffers are handled. We need to switch over to a managed (or view-based) model where the data stored inside the object is a proxy to a Vulkan object that can dynamically be swapped around.
 
 **If you are cherry-picking a commit into an rc/ branch**: add the release note under the
 appropriate header in [RELEASE_NOTES.md](./RELEASE_NOTES.md).

README.md

@@ -31,7 +31,7 @@ repositories {
 }
 
 dependencies {
-    implementation 'com.google.android.filament:filament-android:1.65.1'
+    implementation 'com.google.android.filament:filament-android:1.68.3'
 }
 ```
 
@@ -51,7 +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:
 
 ```shell
-pod 'Filament', '~> 1.65.1'
+pod 'Filament', '~> 1.68.3'
 ```
 
 ## Documentation

RELEASE_NOTES.md

@@ -7,6 +7,54 @@ A new header is inserted each time a *tag* is created.
 Instead, if you are authoring a PR for the main branch, add your release note to
 [NEW_RELEASE_NOTES.md](./NEW_RELEASE_NOTES.md).
 
+## v1.68.3
+
+- materials: added support for the glTF `KHR_materials_dispersion` extension, which adds dispersion for refractive objects
+
+## v1.68.2
+
+- Support `setPresentationTime` with the Metal backend.
+
+## v1.68.1
+
+
+## v1.68.0
+
+- engine: add `View::getLastDynamicResolutionScale()` (b/457753622)
+- Metal: report GPU errors to the platform via `debugUpdateStat` (b/431665753).
+- materials: Make Material Instances' UBO descriptor use dynamic offsets. [⚠️ **Recompile Materials**]
+
+## v1.67.1
+
+- Metal: Add support for the `SwapChain::CONFIG_MSAA_4_SAMPLES` flag.
+- third_party: Optionally add libwebp to build
+  - controlled by cmake flag FILAMENT_SUPPORTS_WEBP_TEXTURES, defaults to OFF
+  - actual webp texture support for libs/gltfio coming in subsequent change
+
+## v1.67.0
+
+- materials: Add a new API getParameterTransformName that will return the value of the transformName field of a sampler
+parameter. [⚠️ **Recompile Materials**]
+
+## v1.66.2
+
+
+## v1.66.1
+
+- filamat: Removed a dependency on Glslang's deprecated SPIR-V remapper.
+  The functionality is already implemented by calling the CanonicalizeIds pass
+  in the SPIRV-Tools, and should be a non-functional change.
+
+## v1.66.0
+
+- materials: include default values of spec constants in material metadata [⚠️ **Recompile Materials**]
+
+## v1.65.4
+
+
+## v1.65.3
+
+
 ## v1.65.2
 
 

android/build.gradle

@@ -100,7 +100,7 @@ buildscript {
         'kotlin': '2.0.21',
         'kotlin_coroutines': '1.9.0',
         'buildTools': '35.0.0',
-        'ndk': '27.0.11718014',
+        'ndk': '29.0.14206865',
         'androidx_core': '1.13.1',
         'androidx_annotations': '1.9.0'
     ]
@@ -124,6 +124,7 @@ buildscript {
 
     ext.cmakeArgs = [
         "--no-warn-unused-cli",
+        "-DANDROID_WEAK_API_DEFS=ON",
         "-DANDROID_PIE=ON",
         "-DANDROID_PLATFORM=21",
         "-DANDROID_STL=c++_static",

android/filament-android/CMakeLists.txt

@@ -51,10 +51,6 @@ add_library(bluevk STATIC IMPORTED)
 set_target_properties(bluevk PROPERTIES IMPORTED_LOCATION
         ${FILAMENT_DIR}/lib/${ANDROID_ABI}/libbluevk.a)
 
-add_library(vkshaders STATIC IMPORTED)
-set_target_properties(vkshaders PROPERTIES IMPORTED_LOCATION
-        ${FILAMENT_DIR}/lib/${ANDROID_ABI}/libvkshaders.a)
-
 if (FILAMENT_SUPPORTS_WEBGPU)
         add_library(webgpu_dawn STATIC IMPORTED)
         set_target_properties(webgpu_dawn PROPERTIES IMPORTED_LOCATION
@@ -138,6 +134,7 @@ target_include_directories(filament-jni PRIVATE
         ../../filament/backend/include
         ../../third_party/robin-map
         ../../third_party/perfetto
+        ../../libs/bluevk/include
         ../../libs/utils/include)
 
 # Ordering is significant in the following list. The PRIVATE qualifier prevents transitive deps.
@@ -165,10 +162,15 @@ target_link_libraries(filament-jni
     PRIVATE $<$<STREQUAL:${FILAMENT_ENABLE_MATDBG},ON>:matdbg>
     PRIVATE $<$<STREQUAL:${FILAMENT_ENABLE_MATDBG},ON>:filamat>
     PRIVATE $<$<STREQUAL:${FILAMENT_SUPPORTS_VULKAN},ON>:bluevk>
-    PRIVATE $<$<STREQUAL:${FILAMENT_SUPPORTS_VULKAN},ON>:vkshaders>
     PRIVATE $<$<STREQUAL:${FILAMENT_SUPPORTS_VULKAN},ON>:smol-v>
     PRIVATE $<$<STREQUAL:${FILAMENT_SUPPORTS_WEBGPU},ON>:webgpu_dawn>
 )
 
 # Force a relink when the version script is changed:
 set_target_properties(filament-jni PROPERTIES LINK_DEPENDS ${VERSION_SCRIPT})
+
+if (FILAMENT_SUPPORTS_VULKAN)
+    add_definitions(-DFILAMENT_SUPPORTS_VULKAN=1)
+else()
+    add_definitions(-DFILAMENT_SUPPORTS_VULKAN=0)
+endif()

android/filament-android/src/main/cpp/Engine.cpp

@@ -557,7 +557,8 @@ extern "C" JNIEXPORT void JNICALL Java_com_google_android_filament_Engine_nSetBu
         jboolean disableHandleUseAfterFreeCheck,
         jint preferredShaderLanguage,
         jboolean forceGLES2Context, jboolean assertNativeWindowIsValid,
-        jint gpuContextPriority) {
+        jint gpuContextPriority,
+        jlong sharedUboInitialSizeInBytes) {
     Engine::Builder* builder = (Engine::Builder*) nativeBuilder;
     Engine::Config config = {
             .commandBufferSizeMB = (uint32_t) commandBufferSizeMB,
@@ -576,6 +577,7 @@ extern "C" JNIEXPORT void JNICALL Java_com_google_android_filament_Engine_nSetBu
             .forceGLES2Context = (bool) forceGLES2Context,
             .assertNativeWindowIsValid = (bool) assertNativeWindowIsValid,
             .gpuContextPriority = (Engine::GpuContextPriority) gpuContextPriority,
+            .sharedUboInitialSizeInBytes = (uint32_t) sharedUboInitialSizeInBytes,
     };
     builder->config(&config);
 }

android/filament-android/src/main/cpp/Material.cpp

@@ -25,7 +25,7 @@ using namespace filament;
 
 extern "C" JNIEXPORT jlong JNICALL
 Java_com_google_android_filament_Material_nBuilderBuild(JNIEnv *env, jclass,
-        jlong nativeEngine, jobject buffer_, jint size, jint shBandCount, jint shadowQuality) {
+        jlong nativeEngine, jobject buffer_, jint size, jint shBandCount, jint shadowQuality, jint uboBatchingMode) {
     Engine* engine = (Engine*) nativeEngine;
     AutoBuffer buffer(env, buffer_, size);
     auto builder = Material::Builder();
@@ -33,6 +33,7 @@ Java_com_google_android_filament_Material_nBuilderBuild(JNIEnv *env, jclass,
         builder.sphericalHarmonicsBandCount(shBandCount);
     }
     builder.shadowSamplingQuality((Material::Builder::ShadowSamplingQuality)shadowQuality);
+    builder.uboBatching((Material::UboBatchingMode)uboBatchingMode);
     Material* material = builder
             .package(buffer.getData(), buffer.getSize())
             .build(*engine);
@@ -279,6 +280,17 @@ Java_com_google_android_filament_Material_nHasParameter(JNIEnv* env, jclass,
     return (jboolean) hasParameter;
 }
 
+extern "C" JNIEXPORT jstring JNICALL
+Java_com_google_android_filament_Material_nGetParameterTransformName(JNIEnv* env, jclass,
+        jlong nativeMaterial, jstring samplerName_) {
+    Material* material = (Material*) nativeMaterial;
+    const char* samplerName = env->GetStringUTFChars(samplerName_, 0);
+    const char* transformName = material->getParameterTransformName(samplerName);
+    jstring transformName_ = env->NewStringUTF(transformName ? transformName : "");
+    env->ReleaseStringUTFChars(samplerName_, samplerName);
+    return transformName_;
+}
+
 extern "C"
 JNIEXPORT void JNICALL
 Java_com_google_android_filament_Material_nCompile(JNIEnv *env, jclass clazz,

android/filament-android/src/main/cpp/Renderer.cpp

@@ -208,3 +208,19 @@ Java_com_google_android_filament_Renderer_nSetVsyncTime(JNIEnv *, jclass,
     Renderer *renderer = (Renderer *) nativeRenderer;
     renderer->setVsyncTime(steadyClockTimeNano);
 }
+
+extern "C"
+JNIEXPORT void JNICALL
+Java_com_google_android_filament_Renderer_nSkipNextFrames(JNIEnv *, jclass ,
+    jlong nativeRenderer, jint frameCount) {
+    Renderer *renderer = (Renderer *) nativeRenderer;
+    renderer->skipNextFrames(frameCount);
+}
+
+extern "C"
+JNIEXPORT jint JNICALL
+Java_com_google_android_filament_Renderer_nGetFrameToSkipCount(JNIEnv *, jclass ,
+    jlong nativeRenderer) {
+    Renderer *renderer = (Renderer *) nativeRenderer;
+    return renderer->getFrameToSkipCount();
+}

android/filament-android/src/main/cpp/SkyBox.cpp

@@ -63,6 +63,14 @@ Java_com_google_android_filament_Skybox_nBuilderColor(JNIEnv *,  jclass,
     builder->color({r, g, b, a});
 }
 
+extern "C"
+JNIEXPORT void JNICALL
+Java_com_google_android_filament_Skybox_nBuilderPriority(JNIEnv *,  jclass,
+        jlong nativeSkyBoxBuilder, jint priority) {
+    Skybox::Builder *builder = (Skybox::Builder *) nativeSkyBoxBuilder;
+    builder->priority(uint8_t(priority));
+}
+
 extern "C" JNIEXPORT jlong JNICALL
 Java_com_google_android_filament_Skybox_nBuilderBuild(JNIEnv *env, jclass type,
         jlong nativeSkyBoxBuilder, jlong nativeEngine) {

android/filament-android/src/main/cpp/SwapChain.cpp

@@ -28,9 +28,8 @@ Java_com_google_android_filament_SwapChain_nSetFrameCompletedCallback(JNIEnv* en
         jlong nativeSwapChain, jobject handler, jobject runnable) {
     SwapChain* swapChain = (SwapChain*) nativeSwapChain;
     auto* callback = JniCallback::make(env, handler, runnable);
-    swapChain->setFrameCompletedCallback(nullptr, [callback](SwapChain* swapChain) {
-        JniCallback::postToJavaAndDestroy(callback);
-    });
+    swapChain->setFrameCompletedCallback(callback->getHandler(),
+            [callback](SwapChain* swapChain) { JniCallback::postToJavaAndDestroy(callback); });
 }
 
 extern "C" JNIEXPORT jboolean JNICALL
@@ -53,3 +52,22 @@ Java_com_google_android_filament_SwapChain_nIsProtectedContentSupported(
     Engine* engine = (Engine*) nativeEngine;
     return (jboolean)SwapChain::isProtectedContentSupported(*engine);
 }
+
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_SwapChain_nSetFrameScheduledCallback(JNIEnv* env, jclass,
+        jlong nativeSwapChain, jobject handler, jobject runnable) {
+    SwapChain* swapChain = (SwapChain*) nativeSwapChain;
+    auto* callback = JniCallback::make(env, handler, runnable);
+    swapChain->setFrameScheduledCallback(callback->getHandler(),
+            [callback](backend::PresentCallable) {
+                // Ignore PresentCallable, which is only meaningful with the Metal backend.
+                JniCallback::postToJavaAndDestroy(callback);
+            });
+}
+
+extern "C" JNIEXPORT jboolean JNICALL
+Java_com_google_android_filament_SwapChain_nIsFrameScheduledCallbackSet(
+        JNIEnv *, jclass, jlong nativeSwapChain) {
+    SwapChain* swapChain = (SwapChain*) nativeSwapChain;
+    return (jboolean)swapChain->isFrameScheduledCallbackSet();
+}

android/filament-android/src/main/cpp/Texture.cpp

@@ -21,6 +21,11 @@
 
 #ifdef __ANDROID__
 #include <android/bitmap.h>
+#include <android/hardware_buffer_jni.h>
+#include <backend/platforms/PlatformEGLAndroid.h>
+#   if FILAMENT_SUPPORTS_VULKAN
+#       include <backend/platforms/VulkanPlatformAndroid.h>
+#   endif
 #endif
 
 #include <filament/Engine.h>
@@ -388,6 +393,57 @@ Java_com_google_android_filament_Texture_nSetExternalImage(JNIEnv*, jclass, jlon
     texture->setExternalImage(*engine, (void*)eglImage);
 }
 
+extern "C"
+JNIEXPORT jboolean JNICALL
+Java_com_google_android_filament_Texture_nSetExternalImageByAHB(JNIEnv *env, jclass clazz,
+        jlong nativeTexture, jlong nativeEngine, jobject ahb) {
+    Texture *texture = (Texture *) nativeTexture;
+    Engine *engine = (Engine *) nativeEngine;
+
+#ifdef __ANDROID__
+    Platform* platform = engine->getPlatform();
+    AHardwareBuffer* nativeBuffer = nullptr;
+    if (__builtin_available(android 26, *)) {
+        nativeBuffer = AHardwareBuffer_fromHardwareBuffer(env, ahb);
+    }
+    if (!nativeBuffer) {
+        // either we're not on Android 26, or ahb wasn't a AHardwareBuffer
+        return JNI_FALSE;
+    }
+
+    if (engine->getBackend() == Backend::OPENGL) {
+        // CAVEAT: we assume that Backend::OPENGL on Android implies PlatformEGLAndroid.
+#if UTILS_HAS_RTTI
+        if (!dynamic_cast<PlatformEGLAndroid*>(platform)) {
+            return JNI_FALSE;
+        }
+#endif
+        auto* eglPlatform = (PlatformEGLAndroid*) platform;
+        auto ref = eglPlatform->createExternalImage(nativeBuffer, false);
+        texture->setExternalImage(*engine, ref);
+    }
+
+#if FILAMENT_SUPPORTS_VULKAN
+    else if (engine->getBackend() == Backend::VULKAN) {
+        // CAVEAT: we assume that Backend::VULKAN on Android implies VulkanPlatformAndroid.
+#if UTILS_HAS_RTTI
+        if (!dynamic_cast<VulkanPlatformAndroid*>(platform)) {
+            return JNI_FALSE;
+        }
+#endif
+        auto* vulkanPlatform = (VulkanPlatformAndroid*) platform;
+        auto ref = vulkanPlatform->createExternalImage(nativeBuffer, false);
+        texture->setExternalImage(*engine, ref);
+    }
+#endif // FILAMENT_SUPPORTS_VULKAN
+    // success!
+    return JNI_TRUE;
+#else
+    // other platforms could come here
+    return JNI_FALSE;
+#endif // __ANDROID__
+}
+
 extern "C" JNIEXPORT void JNICALL
 Java_com_google_android_filament_Texture_nSetExternalStream(JNIEnv*, jclass,
         jlong nativeTexture, jlong nativeEngine, jlong nativeStream) {
@@ -607,3 +663,4 @@ Java_com_google_android_filament_android_TextureHelper_nSetBitmapWithCallback(JN
 }
 
 #endif
+

android/filament-android/src/main/cpp/View.cpp

@@ -147,6 +147,15 @@ Java_com_google_android_filament_View_nSetDynamicResolutionOptions(JNIEnv*, jcla
     view->setDynamicResolutionOptions(options);
 }
 
+extern "C" JNIEXPORT void JNICALL
+Java_com_google_android_filament_View_nGetLastDynamicResolutionScale(JNIEnv *env, jclass, jlong nativeView, jfloatArray out_) {
+    jfloat* out = env->GetFloatArrayElements(out_, nullptr);
+    View *view = (View *) nativeView;
+    math::float2 result = view->getLastDynamicResolutionScale();
+    std::copy_n(result.v, 2, out);
+    env->ReleaseFloatArrayElements(out_, out, 0);
+}
+
 extern "C" JNIEXPORT void JNICALL
 Java_com_google_android_filament_View_nSetShadowType(JNIEnv*, jclass, jlong nativeView, jint type) {
     View* view = (View*) nativeView;
@@ -356,6 +365,7 @@ Java_com_google_android_filament_View_nSetFogOptions(JNIEnv *, jclass , jlong na
     view->setFogOptions(options);
 }
 
+
 extern "C" JNIEXPORT void JNICALL
 Java_com_google_android_filament_View_nSetBlendMode(JNIEnv *, jclass , jlong nativeView, jint blendMode) {
     View* view = (View*) nativeView;
@@ -554,3 +564,20 @@ Java_com_google_android_filament_View_nClearFrameHistory(JNIEnv *env, jclass cla
     Engine *engine = (Engine *) nativeEngine;
     view->clearFrameHistory(*engine);
 }
+
+extern "C"
+JNIEXPORT void JNICALL
+Java_com_google_android_filament_View_nSetChannelDepthClearEnabled(JNIEnv *, jclass ,
+        jlong nativeView, jint channel, jboolean enabled) {
+    View* view = (View*) nativeView;
+    view->setChannelDepthClearEnabled((uint8_t) channel, (bool) enabled);
+}
+
+extern "C"
+JNIEXPORT jboolean JNICALL
+Java_com_google_android_filament_View_nIsChannelDepthClearEnabled(JNIEnv *env, jclass clazz,
+        jlong nativeView, jint channel) {
+    // TODO: implement nIsChannelDepthClearEnabled()
+    View* view = (View*) nativeView;
+    return (jboolean)view->isChannelDepthClearEnabled((uint8_t) channel);
+}

android/filament-android/src/main/java/com/google/android/filament/Asserts.java

@@ -99,6 +99,15 @@ final class Asserts {
         }
     }
 
+    @NonNull @Size(min = 2)
+    static float[] assertFloat2(@Nullable float[] out) {
+        if (out == null) out = new float[2];
+        else if (out.length < 2) {
+            throw new ArrayIndexOutOfBoundsException("Array length must be at least 2");
+        }
+        return out;
+    }
+
     @NonNull @Size(min = 4)
     static float[] assertFloat4(@Nullable float[] out) {
         if (out == null) out = new float[4];

android/filament-android/src/main/java/com/google/android/filament/Engine.java

@@ -264,7 +264,8 @@ public class Engine {
                     config.disableHandleUseAfterFreeCheck,
                     config.preferredShaderLanguage.ordinal(),
                     config.forceGLES2Context, config.assertNativeWindowIsValid,
-                    config.gpuContextPriority.ordinal());
+                    config.gpuContextPriority.ordinal(),
+                    config.sharedUboInitialSizeInBytes);
             return this;
         }
 
@@ -525,6 +526,16 @@ public class Engine {
          * GPU context priority level. Controls GPU work scheduling and preemption.
          */
         public GpuContextPriority gpuContextPriority = GpuContextPriority.DEFAULT;
+
+        /**
+         * The initial size in bytes of the shared uniform buffer used for material instance batching.
+         *
+         * If the buffer runs out of space during a frame, it will be automatically reallocated
+         * with a larger capacity. Setting an appropriate initial size can help avoid runtime
+         * reallocations, which can cause a minor performance stutter, at the cost of higher
+         * initial memory usage.
+         */
+        public long sharedUboInitialSizeInBytes = 256 * 64;
     }
 
     private Engine(long nativeEngine, Config config) {
@@ -1529,7 +1540,8 @@ public class Engine {
             boolean disableHandleUseAfterFreeCheck,
             int preferredShaderLanguage,
             boolean forceGLES2Context, boolean assertNativeWindowIsValid,
-            int gpuContextPriority);
+            int gpuContextPriority,
+            long sharedUboInitialSizeInBytes);
     private static native void nSetBuilderFeatureLevel(long nativeBuilder, int ordinal);
     private static native void nSetBuilderSharedContext(long nativeBuilder, long sharedContext);
     private static native void nSetBuilderPaused(long nativeBuilder, boolean paused);

android/filament-android/src/main/java/com/google/android/filament/Material.java

@@ -261,6 +261,20 @@ public class Material {
         LOW
     }
 
+    /**
+     * Defines whether a material instance should use UBO batching or not.
+     */
+    public enum UboBatchingMode {
+        /**
+         * For default, it follows the engine settings.
+         * If UBO batching is enabled on the engine and the material domain is SURFACE, it
+         * turns on the UBO batching. Otherwise, it turns off the UBO batching.
+        */
+        DEFAULT,
+        /** Disable the Ubo Batching for this material */
+        DISABLED
+    }
+
     public static class UserVariantFilterBit {
         /** Directional lighting */
         public static int DIRECTIONAL_LIGHTING = 0x01;
@@ -372,6 +386,7 @@ public class Material {
         private int mSize;
         private int mShBandCount = 0;
         private ShadowSamplingQuality mShadowSamplingQuality = ShadowSamplingQuality.LOW;
+        private UboBatchingMode mUboBatchingMode = UboBatchingMode.DEFAULT;
 
 
         /**
@@ -416,6 +431,17 @@ public class Material {
             return this;
         }
 
+        /**
+         * Set the batching mode of the instances created from this material.
+         * @param uboBatchingMode
+         * @return Reference to this Builder for chaining calls.
+         */
+        @NonNull
+        public Builder uboBatching(UboBatchingMode mode) {
+            mUboBatchingMode = mode;
+            return this;
+        }
+
         /**
          * Creates and returns the Material object.
          *
@@ -428,7 +454,7 @@ public class Material {
         @NonNull
         public Material build(@NonNull Engine engine) {
             long nativeMaterial = nBuilderBuild(engine.getNativeObject(),
-                mBuffer, mSize, mShBandCount, mShadowSamplingQuality.ordinal());
+                mBuffer, mSize, mShBandCount, mShadowSamplingQuality.ordinal(), mUboBatchingMode.ordinal());
             if (nativeMaterial == 0) throw new IllegalStateException("Couldn't create Material");
             return new Material(nativeMaterial);
         }
@@ -787,6 +813,21 @@ public class Material {
         return nHasParameter(getNativeObject(), name);
     }
 
+    /**
+     * 
+     * Returns the name of the transform parameter associated with the given sampler parameter.
+     * In the case the parameter doesn't have a transform name field, it will return an empty string.
+     * 
+     * @param samplerName the name of the sampler parameter to query.
+     * 
+     * @see
+     * <a href="https://google.github.io/filament/Materials.html#materialdefinitions/materialblock/general:parameters">
+     * General: parameters</a>
+     */
+    public String getParameterTransformName(@NonNull String samplerName) {
+        return nGetParameterTransformName(getNativeObject(), samplerName);
+    }
+
     /**
      * Sets the value of a bool parameter on this material's default instance.
      *
@@ -1079,7 +1120,7 @@ public class Material {
         mNativeObject = 0;
     }
 
-    private static native long nBuilderBuild(long nativeEngine, @NonNull Buffer buffer, int size, int shBandCount, int shadowQuality);
+    private static native long nBuilderBuild(long nativeEngine, @NonNull Buffer buffer, int size, int shBandCount, int shadowQuality, int uboBatchingMode);
     private static native long nCreateInstance(long nativeMaterial);
     private static native long nCreateInstanceWithName(long nativeMaterial, @NonNull String name);
     private static native long nGetDefaultInstance(long nativeMaterial);
@@ -1111,4 +1152,5 @@ public class Material {
     private static native int nGetRequiredAttributes(long nativeMaterial);
 
     private static native boolean nHasParameter(long nativeMaterial, @NonNull String name);
+    private static native String nGetParameterTransformName(long nativeMaterial, @NonNull String samplerName);
 }

android/filament-android/src/main/java/com/google/android/filament/RenderableManager.java

@@ -332,7 +332,7 @@ public class RenderableManager {
         }
 
         /**
-         * Set the channel this renderable is associated to. There can be 4 channels.
+         * Set the channel this renderable is associated to. There can be 8 channels.
          *
          * <p>All renderables in a given channel are rendered together, regardless of anything else.
          * They are sorted as usual within a channel.</p>
@@ -342,7 +342,7 @@ public class RenderableManager {
          * <p>Channels 0 and 1 may not have render primitives using a material with `refractionType`
          * set to `screenspace`.</p>
          *
-         * @param channel clamped to the range [0..3], defaults to 2.
+         * @param channel clamped to the range [0..7], defaults to 2.
          *
          * @return Builder reference for chaining calls.
          *
@@ -351,7 +351,7 @@ public class RenderableManager {
          * @see RenderableManager::setBlendOrderAt()
          */
         @NonNull
-        public Builder channel(@IntRange(from = 0, to = 3) int channel) {
+        public Builder channel(@IntRange(from = 0, to = 7) int channel) {
             nBuilderChannel(mNativeBuilder, channel);
             return this;
         }
@@ -730,7 +730,7 @@ public class RenderableManager {
      *
      * @see Builder#channel
      */
-    public void setChannel(@EntityInstance int i, @IntRange(from = 0, to = 3) int channel) {
+    public void setChannel(@EntityInstance int i, @IntRange(from = 0, to = 7) int channel) {
         nSetChannel(mNativeObject, i, channel);
     }
 

android/filament-android/src/main/java/com/google/android/filament/Renderer.java

@@ -732,6 +732,22 @@ public class Renderer {
         nResetUserTime(getNativeObject());
     }
 
+    /**
+     * Requests the next frameCount frames to be skipped. For Debugging.
+     * @param frameCount number of frames to skip.
+     */
+    public void skipNextFrames(int frameCount) {
+        nSkipNextFrames(getNativeObject(), frameCount);
+    }
+
+    /**
+     * Remainder count of frame to be skipped
+     * @return remaining frames to be skipped
+     */
+    public int getFrameToSkipCount() {
+        return nGetFrameToSkipCount(getNativeObject());
+    }
+
     public long getNativeObject() {
         if (mNativeObject == 0) {
             throw new IllegalStateException("Calling method on destroyed Renderer");
@@ -773,4 +789,7 @@ public class Renderer {
             float interval, float headRoomRatio, float scaleRate, int history);
     private static native void nSetClearOptions(long nativeRenderer,
             float r, float g, float b, float a, boolean clear, boolean discard);
+
+    private static native void nSkipNextFrames(long nativeObject, int frameCount);
+    private static native int nGetFrameToSkipCount(long nativeObject);
 }

android/filament-android/src/main/java/com/google/android/filament/Skybox.java

@@ -155,6 +155,24 @@ public class Skybox {
             return this;
         }
 
+        /**
+         * Set the rendering priority of the Skybox. By default, it is set to the lowest
+         * priority (7) such that the Skybox is always rendered after the opaque objects,
+         * to reduce overdraw when depth culling is enabled.
+         *
+         * @param priority clamped to the range [0..7], defaults to 4; 7 is lowest priority
+         *                 (rendered last).
+         *
+         * @return Builder reference for chaining calls.
+         *
+         * @see RenderableManager.Builder#priority
+         */
+        @NonNull
+        public Builder priority(@IntRange(from = 0, to = 7) int priority) {
+            nBuilderPriority(mNativeBuilder, priority);
+            return this;
+        }
+
         /**
          * Creates a <code>Skybox</code> object
          *
@@ -262,6 +280,7 @@ public class Skybox {
     private static native void nBuilderShowSun(long nativeSkyboxBuilder, boolean show);
     private static native void nBuilderIntensity(long nativeSkyboxBuilder, float intensity);
     private static native void nBuilderColor(long nativeSkyboxBuilder, float r, float g, float b, float a);
+    private static native void nBuilderPriority(long nativeSkyboxBuilder, int priority);
     private static native long nBuilderBuild(long nativeSkyboxBuilder, long nativeEngine);
     private static native void nSetLayerMask(long nativeSkybox, int select, int value);
     private static native int  nGetLayerMask(long nativeSkybox);

android/filament-android/src/main/java/com/google/android/filament/SwapChain.java

@@ -139,6 +139,78 @@ public class SwapChain {
         nSetFrameCompletedCallback(getNativeObject(), handler, callback);
     }
 
+    /**
+     * FrameScheduledCallback is a callback function that notifies an application about the status
+     * of a frame after Filament has finished its processing.
+     *
+     * <p>
+     * The exact timing and semantics of this callback differ depending on the graphics backend in
+     * use.
+     * </p>
+     *
+     * <h3>Metal Backend</h3>
+     * <p>
+     * With the Metal backend, this callback signifies that Filament has completed all CPU-side
+     * processing for a frame and the frame is ready to be scheduled for presentation.
+     * </p>
+     *
+     * <p>
+     * Typically, Filament is responsible for scheduling the frame's presentation to the SwapChain.
+     * If a FrameScheduledCallback is set, however, the application bears the responsibility of
+     * scheduling the frame for presentation by calling the PresentCallable passed to the callback
+     * function. In this mode, Filament will not automatically schedule the frame for presentation.
+     * </p>
+     *
+     * <p>
+     * When using the Metal backend, if your application delays the call to the PresentCallable
+     * (e.g., by invoking it on a separate thread), you must ensure all PresentCallables have been
+     * called before shutting down the Filament Engine. You can guarantee this by calling
+     * Engine.flushAndWait() before Engine.shutdown(). This is necessary to ensure the Engine has
+     * a chance to clean up all memory related to frame presentation.
+     * </p>
+     *
+     * <h3>Other Backends (OpenGL, Vulkan, WebGPU)</h3>
+     * <p>
+     * On other backends, this callback serves as a notification that Filament has completed all
+     * CPU-side processing for a frame. Filament proceeds with its normal presentation logic
+     * automatically, and the PresentCallable passed to the callback is a no-op that can be safely
+     * ignored.
+     * </p>
+     *
+     * <h3>General Behavior</h3>
+     * <p>
+     * A FrameScheduledCallback can be set on an individual SwapChain through
+     * setFrameScheduledCallback. Each SwapChain can have only one callback set per frame. If
+     * setFrameScheduledCallback is called multiple times on the same SwapChain before
+     * Renderer.endFrame(), the most recent call effectively overwrites any previously set callback.
+     * </p>
+     *
+     * <p>
+     * The callback set by setFrameScheduledCallback is "latched" when Renderer.endFrame() is
+     * executed. At this point, the callback is fixed for the frame that was just encoded.
+     * Subsequent calls to setFrameScheduledCallback after endFrame() will apply to the next frame.
+     * </p>
+     *
+     * <p>
+     * Use setFrameScheduledCallback() (with default arguments) to unset the callback.
+     * </p>
+     *
+     * @param handler     A {@link java.util.concurrent.Executor Executor}.
+     * @param callback    The Runnable callback to invoke when frame processing is complete.
+     */
+    public void setFrameScheduledCallback(@NonNull Object handler, @NonNull Runnable callback) {
+        nSetFrameScheduledCallback(getNativeObject(), handler, callback);
+    }
+
+    /**
+     * Returns whether this SwapChain currently has a FrameScheduledCallback set.
+     *
+     * @return true, if the last call to setFrameScheduledCallback set a callback
+     */
+    public boolean isFrameScheduledCallbackSet() {
+        return nIsFrameScheduledCallbackSet(getNativeObject());
+    }
+
     public long getNativeObject() {
         if (mNativeObject == 0) {
             throw new IllegalStateException("Calling method on destroyed SwapChain");
@@ -151,6 +223,8 @@ public class SwapChain {
     }
 
     private static native void nSetFrameCompletedCallback(long nativeSwapChain, Object handler, Runnable callback);
+    private static native void nSetFrameScheduledCallback(long nativeSwapChain, Object handler, Runnable callback);
+    private static native boolean nIsFrameScheduledCallbackSet(long nativeSwapChain);
     private static native boolean nIsSRGBSwapChainSupported(long nativeEngine);
     private static native boolean nIsMSAASwapChainSupported(long nativeEngine, int samples);
     private static native boolean nIsProtectedContentSupported(long nativeEngine);

android/filament-android/src/main/java/com/google/android/filament/Texture.java

@@ -71,6 +71,16 @@ import static com.google.android.filament.Texture.Type.COMPRESSED;
  * @see MaterialInstance#setParameter(String, Texture, TextureSampler)
  */
 public class Texture {
+
+    private static Class<?> HardwareBufferClass = null;
+
+    static {
+        try {
+            HardwareBufferClass = Class.forName("android.hardware.HardwareBuffer");
+        } catch (ClassNotFoundException ignored) {
+        }
+    }
+
     private static final Sampler[] sSamplerValues = Sampler.values();
     private static final InternalFormat[] sInternalFormatValues = InternalFormat.values();
 
@@ -1172,6 +1182,38 @@ public class Texture {
         nSetExternalImage(getNativeObject(), engine.getNativeObject(), eglImage);
     }
 
+    /**
+     * Specifies the external image to associate with this <code>Texture</code>.
+     *
+     * <p>Typically, the external image is OS specific, and can be a video or camera frame.
+     * There are many restrictions when using an external image as a texture, such as:</p>
+     * <ul>
+     *   <li> only the level of detail (lod) 0 can be specified</li>
+     *   <li> only nearest or linear filtering is supported</li>
+     *   <li> the size and format of the texture is defined by the external image</li>
+     *   <li> only the CLAMP_TO_EDGE wrap mode is supported</li>
+     * </ul>
+     *
+     * @param engine    {@link Engine} this texture is associated to. Must be the
+     *                  instance passed to {@link Builder#build Builder.build()}.
+     * @param externalImageRef An OS specific Object. On Android it must be a
+     *                         <code>android.hardware.HardwareBuffer</code>
+     */
+    public void setExternalImage(@NonNull Engine engine, Object externalImageRef) {
+        if (HardwareBufferClass != null) {
+            if (!HardwareBufferClass.isInstance(externalImageRef)) {
+                throw new IllegalArgumentException("externalImageRef must be a AHardwareBuffer");
+            }
+            if (!nSetExternalImageByAHB(getNativeObject(), engine.getNativeObject(), externalImageRef)) {
+                throw new IllegalStateException("Error setting AHardwareBuffer as external image");
+            }
+        } else {
+            throw new UnsupportedOperationException(
+                "setExternalImage(Engine, Object) not supported on this platform");
+        }
+    }
+
+
     /**
      * Specifies the external stream to associate with this <code>Texture</code>.
      *
@@ -1364,6 +1406,8 @@ public class Texture {
     private static native void nSetExternalImage(
             long nativeObject, long nativeEngine, long eglImage);
 
+    private static native boolean nSetExternalImageByAHB(long nativeTexture, long nativeObject, Object ahb);
+
     private static native void nSetExternalStream(long nativeTexture,
             long nativeEngine, long nativeStream);
 

android/filament-android/src/main/java/com/google/android/filament/TextureSampler.java

@@ -294,8 +294,8 @@ public class TextureSampler {
     /**
      * This controls anisotropic filtering.
      *
-     * @param anisotropy Amount of anisotropy, should be a power-of-two. The default is 0.
-     *                   The maximum permissible value is 7.
+     * @param anisotropy Amount of anisotropy, should be a power-of-two. The default is 1.
+     *                   The maximum permissible value is 128.
      */
     public void setAnisotropy(float anisotropy) {
         mSampler = nSetAnisotropy(mSampler, anisotropy);

android/filament-android/src/main/java/com/google/android/filament/View.java

@@ -25,7 +25,6 @@ import java.util.EnumSet;
 
 import static com.google.android.filament.Asserts.assertFloat3In;
 import static com.google.android.filament.Asserts.assertFloat4In;
-import static com.google.android.filament.Colors.LinearColor;
 
 import com.google.android.filament.proguard.UsedByNative;
 
@@ -291,6 +290,25 @@ public class View {
         return mViewport;
     }
 
+    /**
+     * Sets whether a channel must clear the depth buffer before all primitives are rendered.
+     * Channel depth clear is off by default for all channels.
+     * This is orthogonal to Renderer::setClearOptions().
+     * @param channel between 0 and 7
+     * @param enabled true to enable clear, false to disable
+     */
+    void setChannelDepthClearEnabled(@IntRange(from = 0, to = 7) int channel, boolean enabled) {
+        nSetChannelDepthClearEnabled(getNativeObject(), channel, enabled);
+    }
+
+    /**
+     * @param channel between 0 and 7
+     * @return true if this channel has depth clear enabled.
+     */
+    boolean isChannelDepthClearEnabled(@IntRange(from = 0, to = 7) int channel) {
+        return nIsChannelDepthClearEnabled(getNativeObject(), channel);
+    }
+
     /**
      * Sets the blending mode used to draw the view into the SwapChain.
      *
@@ -655,6 +673,21 @@ public class View {
         return mDynamicResolution;
     }
 
+    /**
+     * Returns the last dynamic resolution scale factor used by this view. This value is updated
+     * when Renderer::render(View*) is called
+     * @param out A 2-float array where the value will be stored, or null in which case the array is
+     *            allocated.
+     * @return A 2-float array containing the horizontal and the vertical scale factors
+     * @see Renderer#render(View)
+     */
+    @NonNull @Size(min = 2)
+    public float[] getLastDynamicResolutionScale(@Nullable @Size(min = 2) float[] out) {
+        out = Asserts.assertFloat2(out);
+        nGetLastDynamicResolutionScale(getNativeObject(), out);
+        return out;
+    }
+
     /**
      * Sets the rendering quality for this view (e.g. color precision).
      *
@@ -1298,6 +1331,7 @@ public class View {
     private static native void nSetDithering(long nativeView, int dithering);
     private static native int nGetDithering(long nativeView);
     private static native void nSetDynamicResolutionOptions(long nativeView, boolean enabled, boolean homogeneousScaling, float minScale, float maxScale, float sharpness, int quality);
+    private static native void nGetLastDynamicResolutionScale(long nativeView, float[] out);
     private static native void nSetRenderQuality(long nativeView, int hdrColorBufferQuality);
     private static native void nSetDynamicLightingOptions(long nativeView, float zLightNear, float zLightFar);
     private static native void nSetShadowType(long nativeView, int type);
@@ -1318,6 +1352,8 @@ public class View {
             boolean lensFlare, boolean starburst, float chromaticAberration, int ghostCount, float ghostSpacing, float ghostThreshold, float haloThickness, float haloRadius, float haloThreshold);
     private static native void nSetFogOptions(long nativeView, float distance, float maximumOpacity, float height, float heightFalloff, float cutOffDistance, float v, float v1, float v2, float density, float inScatteringStart, float inScatteringSize, boolean fogColorFromIbl, long skyColorNativeObject, boolean enabled);
     private static native void nSetStereoscopicOptions(long nativeView, boolean enabled);
+    private static native void nSetChannelDepthClearEnabled(long nativeView, int channel, boolean enabled);
+    private static native boolean nIsChannelDepthClearEnabled(long nativeView, int channel);
     private static native void nSetBlendMode(long nativeView, int blendMode);
     private static native void nSetDepthOfFieldOptions(long nativeView, float cocScale, float maxApertureDiameter, boolean enabled, int filter,
             boolean nativeResolution, int foregroundRingCount, int backgroundRingCount, int fastGatherRingCount, int maxForegroundCOC, int maxBackgroundCOC);
@@ -1615,7 +1651,7 @@ public class View {
          *
          *  This value is used as a tint instead, when fogColorFromIbl is enabled.
          *
-         *  @see fogColorFromIbl
+         *  @see #fogColorFromIbl
          */
         @NonNull @Size(min = 3)
         public float[] color = {1.0f, 1.0f, 1.0f};
@@ -1656,7 +1692,7 @@ public class View {
          *
          * `fogColorFromIbl` is ignored when skyTexture is specified.
          *
-         * @see skyColor
+         * @see #skyColor
          */
         public boolean fogColorFromIbl = false;
         /**
@@ -1674,7 +1710,7 @@ public class View {
          * In `linearFog` mode mipmap level 0 is always used.
          *
          * @see Texture
-         * @see fogColorFromIbl
+         * @see #fogColorFromIbl
          */
         @Nullable
         public Texture skyColor = null;
@@ -1796,7 +1832,8 @@ public class View {
     /**
      * Structure used to set the precision of the color buffer and related quality settings.
      *
-     * @see setRenderQuality, getRenderQuality
+     * @see #setRenderQuality
+     * @see #getRenderQuality
      */
     public static class RenderQuality {
         /**
@@ -1814,7 +1851,7 @@ public class View {
 
     /**
      * Options for screen space Ambient Occlusion (SSAO) and Screen Space Cone Tracing (SSCT)
-     * @see setAmbientOcclusionOptions()
+     * @see #setAmbientOcclusionOptions
      */
     public static class AmbientOcclusionOptions {
         public enum AmbientOcclusionType {
@@ -1966,7 +2003,7 @@ public class View {
 
     /**
      * Options for Multi-Sample Anti-aliasing (MSAA)
-     * @see setMultiSampleAntiAliasingOptions()
+     * @see #setMultiSampleAntiAliasingOptions
      */
     public static class MultiSampleAntiAliasingOptions {
         /**
@@ -1996,7 +2033,7 @@ public class View {
      * `feedback` of 0.1 effectively accumulates a maximum of 19 samples in steady state.
      * see "A Survey of Temporal Antialiasing Techniques" by Lei Yang and all for more information.
      *
-     * @see setTemporalAntiAliasingOptions()
+     * @see #setTemporalAntiAliasingOptions
      */
     public static class TemporalAntiAliasingOptions {
         public enum BoxType {
@@ -2098,7 +2135,7 @@ public class View {
 
     /**
      * Options for Screen-space Reflections.
-     * @see setScreenSpaceReflectionsOptions()
+     * @see #setScreenSpaceReflectionsOptions
      */
     public static class ScreenSpaceReflectionsOptions {
         /**
@@ -2132,7 +2169,9 @@ public class View {
 
     /**
      * List of available post-processing anti-aliasing techniques.
-     * @see setAntiAliasing, getAntiAliasing, setSampleCount
+     * @see #setAntiAliasing
+     * @see #getAntiAliasing
+     * @see #setSampleCount
      */
     public enum AntiAliasing {
         /**
@@ -2161,7 +2200,7 @@ public class View {
 
     /**
      * List of available shadow mapping techniques.
-     * @see setShadowType
+     * @see #setShadowType
      */
     public enum ShadowType {
         /**
@@ -2185,7 +2224,7 @@ public class View {
 
     /**
      * View-level options for VSM Shadowing.
-     * @see setVsmShadowOptions()
+     * @see #setVsmShadowOptions
      * @warning This API is still experimental and subject to change.
      */
     public static class VsmShadowOptions {
@@ -2226,7 +2265,7 @@ public class View {
 
     /**
      * View-level options for DPCF and PCSS Shadowing.
-     * @see setSoftShadowOptions()
+     * @see #setSoftShadowOptions
      * @warning This API is still experimental and subject to change.
      */
     public static class SoftShadowOptions {

android/filament-utils-android/src/main/java/com/google/android/filament/utils/ModelViewer.kt

@@ -16,6 +16,9 @@
 
 package com.google.android.filament.utils
 
+import android.graphics.Bitmap
+import android.os.Handler
+import android.os.Looper
 import android.view.MotionEvent
 import android.view.Surface
 import android.view.SurfaceView
@@ -26,6 +29,7 @@ import com.google.android.filament.android.UiHelper
 import com.google.android.filament.gltfio.*
 import kotlinx.coroutines.*
 import java.nio.Buffer
+import java.nio.ByteBuffer
 
 private const val kNearPlane = 0.05f     // 5 cm
 private const val kFarPlane = 1000.0f    // 1 km
@@ -119,6 +123,8 @@ class ModelViewer(
     private val target = DoubleArray(3)
     private val upward = DoubleArray(3)
 
+    private var debugFrameCallback: ((Bitmap) -> Unit)? = null
+
     init {
         renderer = engine.createRenderer()
         scene = engine.createScene()
@@ -305,10 +311,39 @@ class ModelViewer(
         // Render the scene, unless the renderer wants to skip the frame.
         if (renderer.beginFrame(swapChain!!, frameTimeNanos)) {
             renderer.render(view)
+
+            debugFrameCallback?.let {
+                val viewport = view.viewport
+                val bitmap = Bitmap.createBitmap(viewport.width, viewport.height,
+                        Bitmap.Config.ARGB_8888)
+                val buffer = ByteBuffer.allocateDirect(viewport.width * viewport.height * 4)
+
+                val handler = Handler(Looper.getMainLooper())
+                val pixelBufferDescriptor = Texture.PixelBufferDescriptor(buffer,
+                        Texture.Format.RGBA, Texture.Type.UBYTE, 1, 0, 0, 0, handler) {
+                    buffer.rewind()
+                    bitmap.copyPixelsFromBuffer(buffer)
+                    it(bitmap)
+                }
+                renderer.readPixels(viewport.left, viewport.bottom, viewport.width,
+                                    viewport.height, pixelBufferDescriptor)
+                debugFrameCallback = null
+            }
+
             renderer.endFrame()
         }
     }
 
+    /*
+     * Sets a callback that will be invoked with the next rendered frame as a Bitmap. Note that this
+     * is a one-time callback.
+     *
+     *  @param callback   callback to be invoked with a rendered frame as [Bitmap]
+     */
+    fun debugGetNextFrameCallback(callback: (Bitmap) -> Unit) {
+        debugFrameCallback = callback
+    }
+
     private fun populateScene(asset: FilamentAsset) {
         val rcm = engine.renderableManager
         var count = 0

android/filament-utils-android/src/main/java/com/google/android/filament/utils/TextureLoader.kt

@@ -40,7 +40,21 @@ fun loadTexture(engine: Engine, resources: Resources, resourceId: Int, type: Tex
     options.inPremultiplied = type == TextureType.COLOR
 
     val bitmap = BitmapFactory.decodeResource(resources, resourceId, options)
+    return buildTexture(engine, bitmap, type)
+}
 
+fun loadTexture(engine: Engine, bytes: ByteArray, type: TextureType, offset: Int = 0, length: Int = bytes.size): Texture {
+    val options = BitmapFactory.Options()
+    // Color is the only type of texture we want to pre-multiply with the alpha channel
+    // Pre-multiplication is the default behavior, so we need to turn it off here
+    options.inPremultiplied = type == TextureType.COLOR
+
+    val bitmap = BitmapFactory.decodeByteArray(bytes, offset, length, options)
+    return buildTexture(engine, bitmap, type)
+}
+
+
+private fun buildTexture(engine: Engine, bitmap: Bitmap, type: TextureType): Texture {
     val texture = Texture.Builder()
             .width(bitmap.width)
             .height(bitmap.height)

android/filament-utils-android/src/main/java/com/google/android/filament/utils/Utils.kt

@@ -22,6 +22,7 @@ object Utils {
     /**
      * Initializes the utils JNI layer. Must be called before using any utils functionality.
      */
+    @JvmStatic
     fun init() {
         // Load Filament first to ensure that the NioUtils Java class is available in the JNIEnv.
         Filament.init()

android/gradle.properties

@@ -1,5 +1,5 @@
 GROUP=com.google.android.filament
-VERSION_NAME=1.65.1
+VERSION_NAME=1.68.3
 
 POM_DESCRIPTION=Real-time physically based rendering engine for Android.
 

android/samples/README.md

@@ -80,54 +80,12 @@ frame and the external texture are perfectly synchronized.
 
 ![Stream Test](../../docs/images/samples/sample_stream_test.jpg)
 
-## Prerequisites
+## Building Samples
 
 Before you start, make sure to read [Filament's README](../../README.md). You need to be able to
 compile Filament's native library and Filament's AAR for this project. The easiest way to proceed
 is to install all the required dependencies and to run the following commands at the root of the
-source tree:
+source tree.
 
-```shell
-./build.sh -p desktop -i release
-./build.sh -p android release
-```
+To build the samples, please follow the steps described in [BUILDING.md](../../BUILDING.md#android)
 
-This will build all the native components and the AAR required by this sample application.
-
-If you do not use the build script, you must set the `filament_tools_dir` property when invoking
-Gradle, either from the command line or from `local.properties`. This property must point to the
-distribution/install directory for desktop (produced by make/ninja install). This directory must
-contain `bin/matc` and `bin/cmgen`.
-
-Example:
-```shell
-./gradlew -Pfilament_tools_dir=../../dist-release assembleDebug
-```
-
-## Important: SDK location
-
-Either ensure your `ANDROID_HOME` environment variable is set or make sure the root project
-contains a `local.properties` file with the `sdk.dir` property pointing to your installation of
-the Android SDK.
-
-## Compiling
-
-### Android Studio
-
-You must use the latest stable release of Android Studio. To open the project, point Studio to the
-`android` folder. After opening the project and syncing to gradle, select the sample of your choice
-using the drop-down widget in the toolbar.
-
-To compile and run each sample make sure you have selected the appropriate build variant
-(arm7, arm8, x86 or x86_64). If you are not sure you can simply select the "universal"
-variant which includes all the other ones.
-
-### Command Line
-
-From the `android` directory in the project root:
-
-```shell
-./gradlew :samples:sample-hello-triangle:installDebug
-```
-
-Replace `sample-hello-triangle` with your preferred project.

android/samples/sample-gltf-viewer/build.gradle

@@ -17,12 +17,20 @@ filamentTools {
 }
 
 // don't forget to update MainACtivity.kt when/if changing this.
-tasks.register('copyMesh', Copy) {
+tasks.register('copyDamagedHelmetGltf', Copy) {
+    from file("../../../third_party/models/DamagedHelmet/DamagedHelmet.glb")
+    into file("src/main/assets/models")
+    rename {String fileName -> "helmet.glb"}
+}
+
+// don't forget to update MainACtivity.kt when/if changing this.
+tasks.register('copyBusterGltf', Copy) {
     from "../../../third_party/models/BusterDrone"
     into "src/main/assets/models"
 }
 
-preBuild.dependsOn copyMesh
+preBuild.dependsOn copyDamagedHelmetGltf
+preBuild.dependsOn copyBusterGltf
 
 clean.doFirst {
     delete "src/main/assets"

android/samples/sample-hello-camera/build.gradle

@@ -24,7 +24,7 @@ android {
 
     compileSdkVersion versions.compileSdk
     defaultConfig {
-        applicationId "com.google.android.filament.hellocamera"
+        applicationId "com.google.android.filament.hellocam"
         minSdkVersion 23
         targetSdkVersion versions.targetSdk
     }

android/samples/sample-material-instance-stress/.gitignore

@@ -0,0 +1,12 @@
+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+/.idea/caches
+/.idea/gradle.xml
+.DS_Store
+/build
+/captures
+/src/main/assets
+.externalNativeBuild

android/samples/sample-material-instance-stress/build.gradle

@@ -0,0 +1,52 @@
+plugins {
+    id 'com.android.application'
+    id 'kotlin-android'
+    id 'filament-tools-plugin'
+}
+
+project.ext.isSample = true
+
+kotlin {
+    jvmToolchain(versions.jdk)
+}
+
+filamentTools {
+    materialInputDir = project.layout.projectDirectory.dir("src/main/materials")
+    materialOutputDir = project.layout.projectDirectory.dir("src/main/assets/materials")
+}
+
+clean.doFirst {
+    delete "src/main/assets"
+}
+android {
+    namespace 'com.google.android.filament.materialinstancestress'
+
+    compileSdkVersion versions.compileSdk
+    defaultConfig {
+        applicationId "com.google.android.filament.materialinstancestress"
+        minSdkVersion versions.minSdk
+        targetSdkVersion versions.targetSdk
+    }
+
+    // NOTE: This is a workaround required because the AGP task collectReleaseDependencies
+    //       is not configuration-cache friendly yet; this is only useful for Play publication
+    dependenciesInfo {
+        includeInApk = false
+    }
+
+    // We use the .filamat extension for materials compiled with matc
+    // Telling aapt to not compress them allows to load them efficiently
+    aaptOptions {
+        noCompress 'filamat', 'ktx'
+    }
+
+    compileOptions {
+        sourceCompatibility versions.jdk
+        targetCompatibility versions.jdk
+    }
+}
+
+dependencies {
+    implementation deps.kotlin
+    implementation project(':filament-android')
+}

android/samples/sample-material-instance-stress/src/main/AndroidManifest.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+  <application
+      android:allowBackup="true"
+      android:icon="@mipmap/ic_launcher"
+      android:label="@string/app_name"
+      android:roundIcon="@mipmap/ic_launcher_round"
+      android:supportsRtl="true"
+      android:theme="@style/AppTheme">
+    <activity
+        android:exported="true"
+        android:name=".MainActivity">
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN"/>
+
+        <category android:name="android.intent.category.LAUNCHER"/>
+      </intent-filter>
+    </activity>
+  </application>
+
+</manifest>

android/samples/sample-material-instance-stress/src/main/java/com/google/android/filament/materialinstancestress/MainActivity.kt

@@ -0,0 +1,532 @@
+/*
+ * Copyright (C) 2025 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.
+ */
+
+package com.google.android.filament.materialinstancestress
+
+import android.animation.ValueAnimator
+import android.app.Activity
+import android.opengl.Matrix
+import android.os.Bundle
+import android.view.Choreographer
+import android.view.Surface
+import android.view.SurfaceView
+import android.view.animation.LinearInterpolator
+
+import com.google.android.filament.*
+import com.google.android.filament.RenderableManager.*
+import com.google.android.filament.VertexBuffer.*
+import com.google.android.filament.android.DisplayHelper
+import com.google.android.filament.android.FilamentHelper
+import com.google.android.filament.android.UiHelper
+
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+import java.nio.channels.Channels
+import kotlin.math.cos
+import kotlin.math.sin
+
+class MainActivity : Activity() {
+    // Make sure to initialize Filament first
+    // This loads the JNI library needed by most API calls
+    companion object {
+        init {
+            Filament.init()
+        }
+
+        private const val NUM_CUBES = 1000
+        private const val GRID_SIZE = 10
+        private const val SPACING = 2.5f
+    }
+
+    // The View we want to render into
+    private lateinit var surfaceView: SurfaceView
+    // UiHelper is provided by Filament to manage SurfaceView and SurfaceTexture
+    private lateinit var uiHelper: UiHelper
+    // DisplayHelper is provided by Filament to manage the display
+    private lateinit var displayHelper: DisplayHelper
+    // Choreographer is used to schedule new frames
+    private lateinit var choreographer: Choreographer
+
+    // Engine creates and destroys Filament resources
+    // Each engine must be accessed from a single thread of your choosing
+    // Resources cannot be shared across engines
+    private lateinit var engine: Engine
+    // A renderer instance is tied to a single surface (SurfaceView, TextureView, etc.)
+    private lateinit var renderer: Renderer
+    // A scene holds all the renderable, lights, etc. to be drawn
+    private lateinit var scene: Scene
+    // A view defines a viewport, a scene and a camera for rendering
+    private lateinit var view: View
+    // Should be pretty obvious :)
+    private lateinit var camera: Camera
+
+    private lateinit var material: Material
+    private lateinit var vertexBuffer: VertexBuffer
+    private lateinit var indexBuffer: IndexBuffer
+
+    // Filament entity representing a renderable object
+    @Entity private val renderables = IntArray(NUM_CUBES)
+    private val materialInstances = arrayOfNulls<MaterialInstance>(NUM_CUBES)
+    private val translationMatrices = Array(NUM_CUBES) { FloatArray(16) }
+
+    @Entity private var light = 0
+
+    // A swap chain is Filament's representation of a surface
+    private var swapChain: SwapChain? = null
+
+    private var cameraRadius = 42.7f // Initial distance (calculated from original 15Y, 40Z)
+    private var cameraTheta = 0.0f  // Azimuth (horizontal) in radians
+    private var cameraPhi = 0.358f  // Elevation (vertical) in radians (from original 15Y, 40Z)
+
+    private var mLastX = 0.0f
+    private var mLastY = 0.0f
+    private val DRAG_SPEED = 0.005f
+
+    // Performs the rendering and schedules new frames
+    private val frameScheduler = FrameCallback()
+
+    private val animator = ValueAnimator.ofFloat(0.0f, 360.0f)
+
+    private val animatorListener = object : ValueAnimator.AnimatorUpdateListener {
+        // Pre-allocate matrix to avoid GC churn
+        private val transformMatrix = FloatArray(16)
+
+        override fun onAnimationUpdate(a: ValueAnimator) {
+            val tcm = engine.transformManager
+            val time = a.animatedFraction // 0.0 to 1.0
+
+            // Calculate the sine wave scale factor.
+            // sin(time * 2 * PI) oscillates between -1.0 and 1.0.
+            // We multiply by 0.5f (so it's -0.5 to 0.5) and add 1.0f.
+            // This makes the final 'scale' oscillate between 0.5 and 1.5.
+            val scale = 1.0f + sin(time * 2.0 * Math.PI).toFloat() * 0.5f
+
+            val localScale = (scale - 0.5f) * 0.5f + 0.5f
+
+            for (i in 0 until NUM_CUBES) {
+                val inst = tcm.getInstance(renderables[i])
+                val materialInst = materialInstances[i] ?: continue
+
+                // Get the cube's base position from its stored matrix
+                // The translation is in elements 12 (x), 13 (y), and 14 (z)
+                val baseX = translationMatrices[i][12]
+                val baseY = translationMatrices[i][13]
+                val baseZ = translationMatrices[i][14]
+
+                // Set the transformMatrix to a new translation matrix,
+                // scaled from the center (0,0,0)
+                Matrix.setIdentityM(transformMatrix, 0)
+                Matrix.translateM(transformMatrix, 0,
+                        baseX * scale,
+                        baseY * scale,
+                        baseZ * scale)
+                Matrix.scaleM(transformMatrix, 0, localScale, localScale, localScale)
+
+                tcm.setTransform(inst, transformMatrix)
+
+                // Vary roughness
+                val roughness = 0.5f + 0.5f * sin(time * 2.0 * Math.PI + i * 0.1).toFloat()
+                materialInst.setParameter("roughness", roughness)
+
+                // Vary color (using linear RGB)
+                val r = 0.5f + 0.5f * cos(time * 2.0 * Math.PI + i * 0.5).toFloat()
+                val g = 0.5f + 0.5f * sin(time * 2.0 * Math.PI + i * 0.3).toFloat()
+                val b = 0.5f + 0.5f * cos(time * 2.0 * Math.PI + i * 0.1).toFloat()
+                materialInst.setParameter("baseColor", Colors.RgbType.LINEAR, r, g, b)
+            }
+        }
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        surfaceView = SurfaceView(this)
+        setContentView(surfaceView)
+
+        surfaceView.setOnTouchListener(touchListener)
+        choreographer = Choreographer.getInstance()
+
+        displayHelper = DisplayHelper(this)
+
+        setupSurfaceView()
+        setupFilament()
+        setupView()
+        setupScene()
+    }
+
+    private fun setupSurfaceView() {
+        uiHelper = UiHelper(UiHelper.ContextErrorPolicy.DONT_CHECK)
+        uiHelper.renderCallback = SurfaceCallback()
+        uiHelper.attachTo(surfaceView)
+    }
+
+    private fun setupFilament() {
+        engine = Engine.create()
+        renderer = engine.createRenderer()
+        scene = engine.createScene()
+        view = engine.createView()
+        camera = engine.createCamera(engine.entityManager.create())
+    }
+
+    private fun setupView() {
+        scene.skybox = Skybox.Builder().color(0.035f, 0.035f, 0.035f, 1.0f).build(engine)
+        view.camera = camera
+        view.scene = scene
+    }
+
+    private fun setupScene() {
+        loadMaterial()
+        createMesh()
+
+        val tcm = engine.transformManager
+        val center = (GRID_SIZE - 1) * 0.5f
+
+        for (i in 0 until NUM_CUBES) {
+            // Calculate grid position
+            val x = (i % GRID_SIZE) - center
+            val y = ((i / GRID_SIZE) % GRID_SIZE) - center
+            val z = (i / (GRID_SIZE * GRID_SIZE)) - center
+
+            val posX = x * SPACING
+            val posY = y * SPACING
+            val posZ = z * SPACING
+
+            // Create material instance for this cube
+            materialInstances[i] = material.createInstance()
+
+            // Set initial parameters (will be overwritten by animator, but good practice)
+            materialInstances[i]?.setParameter("baseColor", Colors.RgbType.SRGB, 1.0f, 0.85f, 0.57f)
+            materialInstances[i]?.setParameter("metallic", 0.0f)
+            materialInstances[i]?.setParameter("roughness", 0.3f)
+
+            // Create the renderable entity
+            renderables[i] = EntityManager.get().create()
+
+            // Create the renderable component
+            RenderableManager.Builder(1)
+                .boundingBox(Box(0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f))
+                .geometry(0, PrimitiveType.TRIANGLES, vertexBuffer, indexBuffer, 0, 6 * 6)
+                .material(0, materialInstances[i]!!)
+                .build(engine, renderables[i])
+
+            // Add to scene
+            scene.addEntity(renderables[i])
+
+            // Set its initial transform
+            // Store the base translation matrix
+            Matrix.setIdentityM(translationMatrices[i], 0)
+            Matrix.translateM(translationMatrices[i], 0, posX, posY, posZ)
+
+            // Get the transform component instance
+            val inst = tcm.getInstance(renderables[i])
+            tcm.setTransform(inst, translationMatrices[i])
+        }
+
+        // We now need a light, let's create a directional light
+        light = EntityManager.get().create()
+
+        val (r, g, b) = Colors.cct(5_500.0f)
+        LightManager.Builder(LightManager.Type.DIRECTIONAL)
+                .color(r, g, b)
+                .intensity(110_000.0f)
+                .direction(0.0f, -0.5f, -1.0f)
+                .castShadows(true)
+                .build(engine, light)
+
+        scene.addEntity(light)
+
+        camera.setExposure(16.0f, 1.0f / 125.0f, 100.0f)
+
+        updateCamera()
+
+        startAnimation()
+    }
+
+    private fun loadMaterial() {
+        readUncompressedAsset("materials/lit.filamat").let {
+            material = Material.Builder().payload(it, it.remaining()).build(engine)
+        }
+    }
+
+    private fun createMesh() {
+        val floatSize = 4
+        val shortSize = 2
+        val vertexSize = 3 * floatSize + 4 * floatSize
+
+        // A vertex is a position + a tangent frame:
+        // 3 floats for XYZ position, 4 floats for normal+tangents (quaternion)
+        @Suppress("ArrayInDataClass")
+        data class Vertex(val x: Float, val y: Float, val z: Float, val tangents: FloatArray)
+        fun ByteBuffer.put(v: Vertex): ByteBuffer {
+            putFloat(v.x)
+            putFloat(v.y)
+            putFloat(v.z)
+            v.tangents.forEach { putFloat(it) }
+            return this
+        }
+
+        // 6 faces, 4 vertices per face
+        val vertexCount = 6 * 4
+
+        // Create tangent frames, one per face
+        val tfPX = FloatArray(4)
+        val tfNX = FloatArray(4)
+        val tfPY = FloatArray(4)
+        val tfNY = FloatArray(4)
+        val tfPZ = FloatArray(4)
+        val tfNZ = FloatArray(4)
+
+        MathUtils.packTangentFrame( 0.0f,  1.0f, 0.0f, 0.0f, 0.0f, -1.0f,  1.0f,  0.0f,  0.0f, tfPX)
+        MathUtils.packTangentFrame( 0.0f,  1.0f, 0.0f, 0.0f, 0.0f, -1.0f, -1.0f,  0.0f,  0.0f, tfNX)
+        MathUtils.packTangentFrame(-1.0f,  0.0f, 0.0f, 0.0f, 0.0f, -1.0f,  0.0f,  1.0f,  0.0f, tfPY)
+        MathUtils.packTangentFrame(-1.0f,  0.0f, 0.0f, 0.0f, 0.0f,  1.0f,  0.0f, -1.0f,  0.0f, tfNY)
+        MathUtils.packTangentFrame( 0.0f,  1.0f, 0.0f, 1.0f, 0.0f,  0.0f,  0.0f,  0.0f,  1.0f, tfPZ)
+        MathUtils.packTangentFrame( 0.0f, -1.0f, 0.0f, 1.0f, 0.0f,  0.0f,  0.0f,  0.0f, -1.0f, tfNZ)
+
+        val vertexData = ByteBuffer.allocate(vertexCount * vertexSize)
+                // It is important to respect the native byte order
+                .order(ByteOrder.nativeOrder())
+                // Face -Z
+                .put(Vertex(-1.0f, -1.0f, -1.0f, tfNZ))
+                .put(Vertex(-1.0f,  1.0f, -1.0f, tfNZ))
+                .put(Vertex( 1.0f,  1.0f, -1.0f, tfNZ))
+                .put(Vertex( 1.0f, -1.0f, -1.0f, tfNZ))
+                // Face +X
+                .put(Vertex( 1.0f, -1.0f, -1.0f, tfPX))
+                .put(Vertex( 1.0f,  1.0f, -1.0f, tfPX))
+                .put(Vertex( 1.0f,  1.0f,  1.0f, tfPX))
+                .put(Vertex( 1.0f, -1.0f,  1.0f, tfPX))
+                // Face +Z
+                .put(Vertex(-1.0f, -1.0f,  1.0f, tfPZ))
+                .put(Vertex( 1.0f, -1.0f,  1.0f, tfPZ))
+                .put(Vertex( 1.0f,  1.0f,  1.0f, tfPZ))
+                .put(Vertex(-1.0f,  1.0f,  1.0f, tfPZ))
+                // Face -X
+                .put(Vertex(-1.0f, -1.0f,  1.0f, tfNX))
+                .put(Vertex(-1.0f,  1.0f,  1.0f, tfNX))
+                .put(Vertex(-1.0f,  1.0f, -1.0f, tfNX))
+                .put(Vertex(-1.0f, -1.0f, -1.0f, tfNX))
+                // Face -Y
+                .put(Vertex(-1.0f, -1.0f,  1.0f, tfNY))
+                .put(Vertex(-1.0f, -1.0f, -1.0f, tfNY))
+                .put(Vertex( 1.0f, -1.0f, -1.0f, tfNY))
+                .put(Vertex( 1.0f, -1.0f,  1.0f, tfNY))
+                // Face +Y
+                .put(Vertex(-1.0f,  1.0f, -1.0f, tfPY))
+                .put(Vertex(-1.0f,  1.0f,  1.0f, tfPY))
+                .put(Vertex( 1.0f,  1.0f,  1.0f, tfPY))
+                .put(Vertex( 1.0f,  1.0f, -1.0f, tfPY))
+                // Make sure the cursor is pointing in the right place in the byte buffer
+                .flip()
+
+        // Declare the layout of our mesh
+        vertexBuffer = VertexBuffer.Builder()
+                .bufferCount(1)
+                .vertexCount(vertexCount)
+                // Because we interleave position and color data we must specify offset and stride
+                // We could use de-interleaved data by declaring two buffers and giving each
+                // attribute a different buffer index
+                .attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT3, 0,             vertexSize)
+                .attribute(VertexAttribute.TANGENTS, 0, AttributeType.FLOAT4, 3 * floatSize, vertexSize)
+                .build(engine)
+
+        // Feed the vertex data to the mesh
+        // We only set 1 buffer because the data is interleaved
+        vertexBuffer.setBufferAt(engine, 0, vertexData)
+
+        // Create the indices
+        val indexData = ByteBuffer.allocate(6 * 2 * 3 * shortSize)
+                .order(ByteOrder.nativeOrder())
+        repeat(6) {
+            val i = (it * 4).toShort()
+            indexData
+                    .putShort(i).putShort((i + 1).toShort()).putShort((i + 2).toShort())
+                    .putShort(i).putShort((i + 2).toShort()).putShort((i + 3).toShort())
+        }
+        indexData.flip()
+
+        // 6 faces, 2 triangles per face,
+        indexBuffer = IndexBuffer.Builder()
+                .indexCount(vertexCount * 2)
+                .bufferType(IndexBuffer.Builder.IndexType.USHORT)
+                .build(engine)
+        indexBuffer.setBuffer(engine, indexData)
+    }
+
+    private fun updateCamera() {
+        // Calculate eye position from spherical coordinates
+        val eyeY = cameraRadius * sin(cameraPhi)
+        val horizontalRadius = cameraRadius * cos(cameraPhi)
+        val eyeX = horizontalRadius * sin(cameraTheta)
+        val eyeZ = horizontalRadius * cos(cameraTheta)
+
+        // Point the camera at the center (0,0,0)
+        camera.lookAt(eyeX.toDouble(), eyeY.toDouble(), eyeZ.toDouble(), // eye
+                0.0, 0.0, 0.0, // center
+                0.0, 1.0, 0.0) // up
+    }
+
+    private val touchListener = object : android.view.View.OnTouchListener {
+        override fun onTouch(v: android.view.View?, event: android.view.MotionEvent?): Boolean {
+            if (event == null) return false
+            when (event.action) {
+                android.view.MotionEvent.ACTION_DOWN -> {
+                    mLastX = event.x
+                    mLastY = event.y
+                    return true
+                }
+                android.view.MotionEvent.ACTION_MOVE -> {
+                    val dx = event.x - mLastX
+                    val dy = event.y - mLastY
+
+                    cameraTheta -= dx * DRAG_SPEED
+                    cameraPhi += dy * DRAG_SPEED
+
+                    // Clamp vertical angle to avoid flipping over
+                    cameraPhi = cameraPhi.coerceIn(-1.5f, 1.5f)
+
+                    updateCamera()
+
+                    mLastX = event.x
+                    mLastY = event.y
+                    return true
+                }
+            }
+            return v?.onTouchEvent(event) ?: false
+        }
+    }
+
+    private fun startAnimation() {
+        animator.interpolator = LinearInterpolator()
+        animator.duration = 6000
+        animator.repeatMode = ValueAnimator.RESTART
+        animator.repeatCount = ValueAnimator.INFINITE
+        animator.addUpdateListener(animatorListener)
+        animator.start()
+    }
+
+    override fun onResume() {
+        super.onResume()
+        choreographer.postFrameCallback(frameScheduler)
+        animator.start()
+    }
+
+    override fun onPause() {
+        super.onPause()
+        choreographer.removeFrameCallback(frameScheduler)
+        animator.cancel()
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+
+        // Stop the animation and any pending frame
+        choreographer.removeFrameCallback(frameScheduler)
+        animator.cancel();
+
+        // Always detach the surface before destroying the engine
+        uiHelper.detach()
+
+        // Cleanup all resources
+        engine.destroyEntity(light)
+
+        // Destroy all 1000 entities and material instances
+        for (i in 0 until NUM_CUBES) {
+            engine.destroyEntity(renderables[i])
+            materialInstances[i]?.let { engine.destroyMaterialInstance(it) }
+        }
+
+        engine.destroyRenderer(renderer)
+        engine.destroyVertexBuffer(vertexBuffer)
+        engine.destroyIndexBuffer(indexBuffer)
+        engine.destroyMaterial(material)
+        engine.destroyView(view)
+        engine.destroyScene(scene)
+        engine.destroyCameraComponent(camera.entity)
+
+        // Engine.destroyEntity() destroys Filament related resources only
+        // (components), not the entity itself
+        val entityManager = EntityManager.get()
+        entityManager.destroy(light)
+        for (entity in renderables) {
+            entityManager.destroy(entity)
+        }
+        entityManager.destroy(camera.entity)
+
+        // Destroying the engine will free up any resource you may have forgotten
+        // to destroy, but it's recommended to do the cleanup properly
+        engine.destroy()
+    }
+
+    inner class FrameCallback : Choreographer.FrameCallback {
+        override fun doFrame(frameTimeNanos: Long) {
+            // Schedule the next frame
+            choreographer.postFrameCallback(this)
+
+            // This check guarantees that we have a swap chain
+            if (uiHelper.isReadyToRender) {
+                // If beginFrame() returns false you should skip the frame
+                // This means you are sending frames too quickly to the GPU
+                if (renderer.beginFrame(swapChain!!, frameTimeNanos)) {
+                    renderer.render(view)
+                    renderer.endFrame()
+                }
+            }
+        }
+    }
+
+    inner class SurfaceCallback : UiHelper.RendererCallback {
+        override fun onNativeWindowChanged(surface: Surface) {
+            swapChain?.let { engine.destroySwapChain(it) }
+            swapChain = engine.createSwapChain(surface)
+            displayHelper.attach(renderer, surfaceView.display)
+        }
+
+        override fun onDetachedFromSurface() {
+            displayHelper.detach()
+            swapChain?.let {
+                engine.destroySwapChain(it)
+                // Required to ensure we don't return before Filament is done executing the
+                // destroySwapChain command, otherwise Android might destroy the Surface
+                // too early
+                engine.flushAndWait()
+                swapChain = null
+            }
+        }
+
+        override fun onResized(width: Int, height: Int) {
+            val aspect = width.toDouble() / height.toDouble()
+            camera.setProjection(45.0, aspect, 0.1, 100.0, Camera.Fov.VERTICAL)
+
+            view.viewport = Viewport(0, 0, width, height)
+
+            FilamentHelper.synchronizePendingFrames(engine)
+        }
+    }
+
+    private fun readUncompressedAsset(assetName: String): ByteBuffer {
+        assets.openFd(assetName).use { fd ->
+            val input = fd.createInputStream()
+            val dst = ByteBuffer.allocate(fd.length.toInt())
+
+            val src = Channels.newChannel(input)
+            src.read(dst)
+            src.close()
+
+            return dst.apply { rewind() }
+        }
+    }
+}

android/samples/sample-material-instance-stress/src/main/materials/lit.mat

@@ -0,0 +1,53 @@
+// Simple lit material that defines 3 parameters:
+// - baseColor
+// - roughness
+// - metallic
+//
+// These parameters can be used by the application to change the appearance of the material.
+//
+// This source material must be compiled to a binary material using the matc tool.
+// The command used to compile this material is:
+// matc -p mobile -a opengl -o app/src/main/assets/lit.filamat app/src/materials/lit.mat
+//
+// See build.gradle for an example of how to compile materials automatically
+// Please refer to the documentation for more information about matc and the materials system.
+
+material {
+    name : lit,
+
+    // Dynamic lighting is enabled on this material
+    shadingModel : lit,
+
+    // We don't need to declare a "requires" array, lit materials
+    // always requires the "tangents" vertex attribute (the normal
+    // is required for lighting, tangent/bitangent for normal mapping
+    // and anisotropy)
+
+    // List of parameters exposed by this material
+    parameters : [
+        // The color must be passed in linear space, not sRGB
+        {
+            type : float3,
+            name : baseColor
+        },
+        {
+            type : float,
+            name : roughness
+        },
+        {
+            type : float,
+            name : metallic
+        }
+    ],
+}
+
+fragment {
+    void material(inout MaterialInputs material) {
+        prepareMaterial(material);
+
+        // Nothing fancy here, we simply copy the parameters
+        material.baseColor.rgb = materialParams.baseColor;
+        material.roughness = materialParams.roughness;
+        material.metallic = materialParams.metallic;
+    }
+}

android/samples/sample-material-instance-stress/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,34 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108">
+  <path
+      android:fillType="evenOdd"
+      android:pathData="M32,64C32,64 38.39,52.99 44.13,50.95C51.37,48.37 70.14,49.57 70.14,49.57L108.26,87.69L108,109.01L75.97,107.97L32,64Z"
+      android:strokeColor="#00000000"
+      android:strokeWidth="1">
+    <aapt:attr name="android:fillColor">
+      <gradient
+          android:endX="78.5885"
+          android:endY="90.9159"
+          android:startX="48.7653"
+          android:startY="61.0927"
+          android:type="linear">
+        <item
+            android:color="#44000000"
+            android:offset="0.0"/>
+        <item
+            android:color="#00000000"
+            android:offset="1.0"/>
+      </gradient>
+    </aapt:attr>
+  </path>
+  <path
+      android:fillColor="#FFFFFF"
+      android:fillType="nonZero"
+      android:pathData="M66.94,46.02L66.94,46.02C72.44,50.07 76,56.61 76,64L32,64C32,56.61 35.56,50.11 40.98,46.06L36.18,41.19C35.45,40.45 35.45,39.3 36.18,38.56C36.91,37.81 38.05,37.81 38.78,38.56L44.25,44.05C47.18,42.57 50.48,41.71 54,41.71C57.48,41.71 60.78,42.57 63.68,44.05L69.11,38.56C69.84,37.81 70.98,37.81 71.71,38.56C72.44,39.3 72.44,40.45 71.71,41.19L66.94,46.02ZM62.94,56.92C64.08,56.92 65,56.01 65,54.88C65,53.76 64.08,52.85 62.94,52.85C61.8,52.85 60.88,53.76 60.88,54.88C60.88,56.01 61.8,56.92 62.94,56.92ZM45.06,56.92C46.2,56.92 47.13,56.01 47.13,54.88C47.13,53.76 46.2,52.85 45.06,52.85C43.92,52.85 43,53.76 43,54.88C43,56.01 43.92,56.92 45.06,56.92Z"
+      android:strokeColor="#00000000"
+      android:strokeWidth="1"/>
+</vector>

android/samples/sample-material-instance-stress/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,171 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108">
+  <path
+      android:fillColor="#26A69A"
+      android:pathData="M0,0h108v108h-108z"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M9,0L9,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,0L19,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M29,0L29,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M39,0L39,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M49,0L49,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M59,0L59,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M69,0L69,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M79,0L79,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M89,0L89,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M99,0L99,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,9L108,9"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,19L108,19"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,29L108,29"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,39L108,39"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,49L108,49"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,59L108,59"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,69L108,69"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,79L108,79"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,89L108,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,99L108,99"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,29L89,29"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,39L89,39"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,49L89,49"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,59L89,59"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,69L89,69"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,79L89,79"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M29,19L29,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M39,19L39,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M49,19L49,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M59,19L59,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M69,19L69,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M79,19L79,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+</vector>

android/samples/sample-material-instance-stress/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+  <background android:drawable="@drawable/ic_launcher_background"/>
+  <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+</adaptive-icon>

android/samples/sample-material-instance-stress/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+  <background android:drawable="@drawable/ic_launcher_background"/>
+  <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+</adaptive-icon>

android/samples/sample-material-instance-stress/src/main/res/values/colors.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+  <color name="colorPrimary">#3F51B5</color>
+  <color name="colorPrimaryDark">#303F9F</color>
+  <color name="colorAccent">#FF4081</color>
+</resources>

android/samples/sample-material-instance-stress/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+  <string name="app_name">Material Instance Stress</string>
+</resources>

android/samples/sample-material-instance-stress/src/main/res/values/styles.xml

@@ -0,0 +1,8 @@
+<resources>
+
+  <!-- Base application theme. -->
+  <style name="AppTheme" parent="android:Theme.Material.Light.DarkActionBar">
+    <!-- Customize your theme here. -->
+  </style>
+
+</resources>

android/samples/sample-texture-target/.gitignore

@@ -0,0 +1,12 @@
+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+/.idea/caches
+/.idea/gradle.xml
+.DS_Store
+/build
+/captures
+/src/main/assets
+.externalNativeBuild

android/samples/sample-texture-target/build.gradle

@@ -0,0 +1,53 @@
+plugins {
+    id 'com.android.application'
+    id 'kotlin-android'
+    id 'filament-tools-plugin'
+}
+
+project.ext.isSample = true
+
+kotlin {
+    jvmToolchain(versions.jdk)
+}
+
+filamentTools {
+    materialInputDir = project.layout.projectDirectory.dir("src/main/materials")
+    materialOutputDir = project.layout.projectDirectory.dir("src/main/assets/materials")
+}
+
+clean.doFirst {
+    delete "src/main/assets"
+}
+
+android {
+    namespace 'com.google.android.filament.texturetarget'
+
+    compileSdkVersion versions.compileSdk
+    defaultConfig {
+        applicationId "com.google.android.filament.texturetarget"
+        minSdkVersion 26
+        targetSdkVersion versions.targetSdk
+    }
+
+    // NOTE: This is a workaround required because the AGP task collectReleaseDependencies
+    //       is not configuration-cache friendly yet; this is only useful for Play publication
+    dependenciesInfo {
+        includeInApk = false
+    }
+
+    // We use the .filamat extension for materials compiled with matc
+    // Telling aapt to not compress them allows to load them efficiently
+    aaptOptions {
+        noCompress 'filamat', 'ktx'
+    }
+
+    compileOptions {
+        sourceCompatibility versions.jdk
+        targetCompatibility versions.jdk
+    }
+}
+
+dependencies {
+    implementation deps.kotlin
+    implementation project(':filament-android')
+}

android/samples/sample-texture-target/src/main/AndroidManifest.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+  <application
+      android:allowBackup="true"
+      android:icon="@mipmap/ic_launcher"
+      android:label="@string/app_name"
+      android:roundIcon="@mipmap/ic_launcher_round"
+      android:supportsRtl="true"
+      android:theme="@style/AppTheme">
+    <activity
+        android:exported="true"
+        android:name=".MainActivity">
+      <intent-filter>
+        <action android:name="android.intent.action.MAIN"/>
+
+        <category android:name="android.intent.category.LAUNCHER"/>
+      </intent-filter>
+    </activity>
+  </application>
+
+</manifest>

android/samples/sample-texture-target/src/main/java/com/google/android/filament/texturetarget/MainActivity.kt

@@ -0,0 +1,429 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.android.filament.texturetarget
+
+import android.animation.ValueAnimator
+import android.app.Activity
+import android.hardware.HardwareBuffer
+import android.opengl.Matrix
+import android.os.Bundle
+import android.view.Choreographer
+import android.view.Surface
+import android.view.SurfaceView
+import android.view.animation.LinearInterpolator
+import com.google.android.filament.*
+import com.google.android.filament.RenderableManager.PrimitiveType
+import com.google.android.filament.VertexBuffer.AttributeType
+import com.google.android.filament.VertexBuffer.VertexAttribute
+import com.google.android.filament.android.DisplayHelper
+import com.google.android.filament.android.FilamentHelper
+import com.google.android.filament.android.UiHelper
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+import java.nio.channels.Channels
+import kotlin.math.PI
+import kotlin.math.cos
+import kotlin.math.sin
+
+class MainActivity : Activity() {
+    companion object {
+        init {
+            Filament.init()
+        }
+    }
+
+    private lateinit var surfaceView: SurfaceView
+    private lateinit var uiHelper: UiHelper
+    private lateinit var displayHelper: DisplayHelper
+    private lateinit var choreographer: Choreographer
+
+    private lateinit var engine: Engine
+    private lateinit var renderer: Renderer
+    private lateinit var scene: Scene
+    private lateinit var view: View
+    private lateinit var camera: Camera
+
+    private lateinit var triangleMaterial: Material
+    private lateinit var texturedMaterial: Material
+    private lateinit var triangleVertexBuffer: VertexBuffer
+    private lateinit var triangleIndexBuffer: IndexBuffer
+    private lateinit var quadVertexBuffer: VertexBuffer
+    private lateinit var quadIndexBuffer: IndexBuffer
+
+    @Entity private var triangleRenderable = 0
+    @Entity private var quadRenderable = 0
+
+    private var swapChain: SwapChain? = null
+
+    private val frameScheduler = FrameCallback()
+    private val animator = ValueAnimator.ofFloat(0.0f, 360.0f)
+
+    private var hardwareBuffer: HardwareBuffer? = null
+    private var texture: Texture? = null
+    private var renderTarget: RenderTarget? = null
+
+    private lateinit var offscreenView: View
+    private lateinit var offscreenCamera: Camera
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        surfaceView = SurfaceView(this)
+        setContentView(surfaceView)
+        choreographer = Choreographer.getInstance()
+        displayHelper = DisplayHelper(this)
+        setupSurfaceView()
+        setupFilament()
+        setupView()
+        setupScene()
+    }
+
+    private fun setupSurfaceView() {
+        uiHelper = UiHelper(UiHelper.ContextErrorPolicy.DONT_CHECK)
+        uiHelper.renderCallback = SurfaceCallback()
+        uiHelper.attachTo(surfaceView)
+    }
+
+    private fun setupFilament() {
+        engine = Engine.create()
+        renderer = engine.createRenderer()
+        scene = engine.createScene()
+        view = engine.createView()
+        camera = engine.createCamera(engine.entityManager.create())
+        offscreenView = engine.createView()
+        offscreenCamera = engine.createCamera(engine.entityManager.create())
+    }
+
+    private fun setupView() {
+        scene.skybox = Skybox.Builder()
+            .priority(0)
+            .color(0.0f, 0.0f, 1.0f, 1.0f).build(engine)
+
+        // This is the view that will be drawn on screen.
+        view.camera = camera
+        view.scene = scene
+        view.isPostProcessingEnabled = false
+
+        // This is the view that will be rendered off-screen.
+        offscreenView.camera = offscreenCamera
+        offscreenView.scene = scene
+        offscreenView.isPostProcessingEnabled = false
+    }
+
+    private fun setupScene() {
+        loadMaterials()
+        createTriangleMesh()
+        createQuadMesh()
+
+        // layer 1: skybox
+        // layer 2: triangle
+        // layer 3: quad
+
+        triangleMaterial.defaultInstance.cullingMode = Material.CullingMode.NONE;
+        texturedMaterial.defaultInstance.cullingMode = Material.CullingMode.NONE;
+
+        // The triangle is a regular renderable.
+        triangleRenderable = EntityManager.get().create()
+        RenderableManager.Builder(1)
+            .geometry(0, PrimitiveType.TRIANGLES, triangleVertexBuffer, triangleIndexBuffer, 0, 3)
+            .material(0, triangleMaterial.defaultInstance)
+            .culling(false)
+            .castShadows(false)
+            .receiveShadows(false)
+            .layerMask(7, 2)
+            .build(engine, triangleRenderable)
+
+        // The quad is a regular renderable.
+        quadRenderable = EntityManager.get().create()
+        RenderableManager.Builder(1)
+            .geometry(0, PrimitiveType.TRIANGLES, quadVertexBuffer, quadIndexBuffer, 0, 6)
+            .material(0, texturedMaterial.defaultInstance)
+            .culling(false)
+            .castShadows(false)
+            .receiveShadows(false)
+            .layerMask(7, 4)
+            .build(engine, quadRenderable)
+
+        // We only want to render the triangle in the offscreen view.
+        offscreenView.setVisibleLayers(7, 3)    // render skybox + triangle
+
+        // We only want to render the quad in the on-screen view.
+        view.setVisibleLayers(7, 4)             // render quad only
+
+        scene.addEntity(triangleRenderable)
+        scene.addEntity(quadRenderable)
+
+        startAnimation()
+    }
+
+    private fun loadMaterials() {
+        readUncompressedAsset("materials/baked_color.filamat").let {
+            triangleMaterial = Material.Builder().payload(it, it.remaining()).build(engine)
+        }
+        readUncompressedAsset("materials/textured.filamat").let {
+            texturedMaterial = Material.Builder().payload(it, it.remaining()).build(engine)
+        }
+    }
+
+    private fun createTriangleMesh() {
+        val intSize = 4
+        val floatSize = 4
+        val shortSize = 2
+        val vertexSize = 3 * floatSize + intSize
+
+        data class Vertex(val x: Float, val y: Float, val z: Float, val color: Int)
+        fun ByteBuffer.put(v: Vertex): ByteBuffer {
+            putFloat(v.x)
+            putFloat(v.y)
+            putFloat(v.z)
+            putInt(v.color)
+            return this
+        }
+
+        val vertexCount = 3
+        val a1 = PI * 2.0 / 3.0
+        val a2 = PI * 4.0 / 3.0
+
+        val vertexData = ByteBuffer.allocate(vertexCount * vertexSize)
+            .order(ByteOrder.nativeOrder())
+            .put(Vertex(1.0f, 0.0f, 0.0f, 0xffff0000.toInt()))
+            .put(Vertex(cos(a1).toFloat(), sin(a1).toFloat(), 0.0f, 0xff00ff00.toInt()))
+            .put(Vertex(cos(a2).toFloat(), sin(a2).toFloat(), 0.0f, 0xff0000ff.toInt()))
+            .flip()
+
+        triangleVertexBuffer = VertexBuffer.Builder()
+            .bufferCount(1)
+            .vertexCount(vertexCount)
+            .attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT3, 0, vertexSize)
+            .attribute(VertexAttribute.COLOR, 0, AttributeType.UBYTE4, 3 * floatSize, vertexSize)
+            .normalized(VertexAttribute.COLOR)
+            .build(engine)
+        triangleVertexBuffer.setBufferAt(engine, 0, vertexData)
+
+        val indexData = ByteBuffer.allocate(vertexCount * shortSize)
+            .order(ByteOrder.nativeOrder())
+            .putShort(0)
+            .putShort(1)
+            .putShort(2)
+            .flip()
+
+        triangleIndexBuffer = IndexBuffer.Builder()
+            .indexCount(3)
+            .bufferType(IndexBuffer.Builder.IndexType.USHORT)
+            .build(engine)
+        triangleIndexBuffer.setBuffer(engine, indexData)
+    }
+
+    private fun createQuadMesh() {
+        val floatSize = 4
+        val shortSize = 2
+        val vertexSize = (2 * floatSize) + (2 * floatSize) // position + UV
+
+        data class Vertex(val x: Float, val y: Float, val u: Float, val v: Float)
+        fun ByteBuffer.put(v: Vertex): ByteBuffer {
+            putFloat(v.x)
+            putFloat(v.y)
+            putFloat(v.u)
+            putFloat(v.v)
+            return this
+        }
+
+        val vertexCount = 4
+        val vertexData = ByteBuffer.allocate(vertexCount * vertexSize)
+            .order(ByteOrder.nativeOrder())
+            .put(Vertex(-1.0f, -1.0f, 0.0f, 0.0f))
+            .put(Vertex( 1.0f, -1.0f, 1.0f, 0.0f))
+            .put(Vertex( 1.0f,  1.0f, 1.0f, 1.0f))
+            .put(Vertex(-1.0f,  1.0f, 0.0f, 1.0f))
+            .flip()
+
+        quadVertexBuffer = VertexBuffer.Builder()
+            .bufferCount(1)
+            .vertexCount(vertexCount)
+            .attribute(VertexAttribute.POSITION, 0, AttributeType.FLOAT2, 0, vertexSize)
+            .attribute(VertexAttribute.UV0, 0, AttributeType.FLOAT2, 2 * floatSize, vertexSize)
+            .build(engine)
+        quadVertexBuffer.setBufferAt(engine, 0, vertexData)
+
+        val indexData = ByteBuffer.allocate(6 * shortSize)
+            .order(ByteOrder.nativeOrder())
+            .putShort(0).putShort(1).putShort(2)
+            .putShort(0).putShort(2).putShort(3)
+            .flip()
+
+        quadIndexBuffer = IndexBuffer.Builder()
+            .indexCount(6)
+            .bufferType(IndexBuffer.Builder.IndexType.USHORT)
+            .build(engine)
+        quadIndexBuffer.setBuffer(engine, indexData)
+    }
+
+    private fun startAnimation() {
+        animator.interpolator = LinearInterpolator()
+        animator.duration = 4000
+        animator.repeatMode = ValueAnimator.RESTART
+        animator.repeatCount = ValueAnimator.INFINITE
+        animator.addUpdateListener { a ->
+            val transformMatrix = FloatArray(16)
+            Matrix.setRotateM(transformMatrix, 0, -(a.animatedValue as Float), 0.0f, 0.0f, 1.0f)
+            val tcm = engine.transformManager
+            tcm.setTransform(tcm.getInstance(triangleRenderable), transformMatrix)
+        }
+        animator.start()
+    }
+
+    override fun onResume() {
+        super.onResume()
+        choreographer.postFrameCallback(frameScheduler)
+        animator.start()
+    }
+
+    override fun onPause() {
+        super.onPause()
+        choreographer.removeFrameCallback(frameScheduler)
+        animator.cancel()
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        choreographer.removeFrameCallback(frameScheduler)
+        animator.cancel()
+        uiHelper.detach()
+
+        // Destroy all renderables.
+        scene.remove(triangleRenderable)
+        scene.remove(quadRenderable)
+
+        // Destroy all resources.
+        engine.destroyEntity(triangleRenderable)
+        engine.destroyEntity(quadRenderable)
+        engine.destroyRenderer(renderer)
+        engine.destroyVertexBuffer(triangleVertexBuffer)
+        engine.destroyIndexBuffer(triangleIndexBuffer)
+        engine.destroyVertexBuffer(quadVertexBuffer)
+        engine.destroyIndexBuffer(quadIndexBuffer)
+        engine.destroyMaterial(triangleMaterial)
+        engine.destroyMaterial(texturedMaterial)
+        engine.destroyView(view)
+        engine.destroyView(offscreenView)
+        engine.destroyScene(scene)
+        engine.destroyCameraComponent(camera.entity)
+        engine.destroyCameraComponent(offscreenCamera.entity)
+        renderTarget?.let { engine.destroyRenderTarget(it) }
+        texture?.let { engine.destroyTexture(it) }
+        hardwareBuffer?.close()
+
+        val entityManager = EntityManager.get()
+        entityManager.destroy(triangleRenderable)
+        entityManager.destroy(quadRenderable)
+        entityManager.destroy(camera.entity)
+        entityManager.destroy(offscreenCamera.entity)
+
+        engine.destroy()
+    }
+
+    inner class FrameCallback : Choreographer.FrameCallback {
+        override fun doFrame(frameTimeNanos: Long) {
+            choreographer.postFrameCallback(this)
+            if (uiHelper.isReadyToRender) {
+                if (renderer.beginFrame(swapChain!!, frameTimeNanos)) {
+                    // Render the triangle to the texture.
+                    renderer.render(offscreenView)
+                    // Render the quad to the screen.
+                    renderer.render(view)
+                    renderer.endFrame()
+                }
+            }
+        }
+    }
+
+    inner class SurfaceCallback : UiHelper.RendererCallback {
+        override fun onNativeWindowChanged(surface: Surface) {
+            swapChain?.let { engine.destroySwapChain(it) }
+            swapChain = engine.createSwapChain(surface, uiHelper.swapChainFlags)
+            displayHelper.attach(renderer, surfaceView.display)
+        }
+
+        override fun onDetachedFromSurface() {
+            displayHelper.detach()
+            swapChain?.let {
+                engine.destroySwapChain(it)
+                engine.flushAndWait()
+                swapChain = null
+            }
+        }
+
+        override fun onResized(width: Int, height: Int) {
+            // On-screen camera
+            val zoom = 1.0
+            val aspect = width.toDouble() / height.toDouble()
+            camera.setProjection(Camera.Projection.ORTHO, -aspect * zoom, aspect * zoom, -zoom, zoom, 0.0, 10.0)
+            view.viewport = Viewport(0, 0, width, height)
+
+            // Off-screen camera
+            val offscreenZoom = 1.5
+            offscreenCamera.setProjection(Camera.Projection.ORTHO,
+                -aspect * offscreenZoom, aspect * offscreenZoom,
+                -offscreenZoom, offscreenZoom, 0.0, 10.0)
+            offscreenView.viewport = Viewport(0, 0, width, height)
+
+            // If we have a render target, destroy it.
+            renderTarget?.let { engine.destroyRenderTarget(it) }
+            texture?.let { engine.destroyTexture(it) }
+            hardwareBuffer?.close()
+
+            // Create a new render target.
+            hardwareBuffer = HardwareBuffer.create(width, height,
+                HardwareBuffer.RGBA_8888, 1,
+                HardwareBuffer.USAGE_GPU_SAMPLED_IMAGE or HardwareBuffer.USAGE_GPU_COLOR_OUTPUT)
+
+            texture = Texture.Builder()
+                .width(width)
+                .height(height)
+                .usage(Texture.Usage.COLOR_ATTACHMENT or Texture.Usage.SAMPLEABLE)
+                .sampler(Texture.Sampler.SAMPLER_EXTERNAL)
+                .format(Texture.InternalFormat.RGBA8)
+                .external()
+                .build(engine)
+
+            texture!!.setExternalImage(engine, hardwareBuffer!!)
+
+            renderTarget = RenderTarget.Builder()
+                .texture(RenderTarget.AttachmentPoint.COLOR, texture!!)
+                .build(engine)
+
+            offscreenView.renderTarget = renderTarget
+
+            // Set the texture on the quad material.
+            texturedMaterial.defaultInstance.setParameter("texture", texture!!,
+                TextureSampler(TextureSampler.MinFilter.LINEAR, TextureSampler.MagFilter.LINEAR,
+                    TextureSampler.WrapMode.CLAMP_TO_EDGE))
+
+            FilamentHelper.synchronizePendingFrames(engine)
+        }
+    }
+
+    private fun readUncompressedAsset(assetName: String): ByteBuffer {
+        assets.openFd(assetName).use { fd ->
+            val input = fd.createInputStream()
+            val dst = ByteBuffer.allocate(fd.length.toInt())
+            val src = Channels.newChannel(input)
+            src.read(dst)
+            src.close()
+            return dst.apply { rewind() }
+        }
+    }
+}

android/samples/sample-texture-target/src/main/materials/baked_color.mat

@@ -0,0 +1,18 @@
+material {
+    name : baked_color,
+    shadingModel : unlit,
+    requires : [
+        color
+    ]
+}
+
+fragment {
+    void material(inout MaterialInputs material) {
+        // You must always call the prepareMaterial() function
+        prepareMaterial(material);
+
+        // We set the material's color to the color interpolated from
+        // the model's vertices
+        material.baseColor = getColor();
+    }
+}

android/samples/sample-texture-target/src/main/materials/textured.mat

@@ -0,0 +1,20 @@
+material {
+    name : textured,
+    shadingModel : unlit,
+    parameters : [
+        {
+            type : samplerExternal,
+            name : texture
+        }
+    ],
+    requires: [
+        uv0
+    ]
+}
+
+fragment {
+    void material(inout MaterialInputs material) {
+        prepareMaterial(material);
+        material.baseColor = texture(materialParams_texture, getUV0());
+    }
+}

android/samples/sample-texture-target/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,34 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108">
+  <path
+      android:fillType="evenOdd"
+      android:pathData="M32,64C32,64 38.39,52.99 44.13,50.95C51.37,48.37 70.14,49.57 70.14,49.57L108.26,87.69L108,109.01L75.97,107.97L32,64Z"
+      android:strokeColor="#00000000"
+      android:strokeWidth="1">
+    <aapt:attr name="android:fillColor">
+      <gradient
+          android:endX="78.5885"
+          android:endY="90.9159"
+          android:startX="48.7653"
+          android:startY="61.0927"
+          android:type="linear">
+        <item
+            android:color="#44000000"
+            android:offset="0.0"/>
+        <item
+            android:color="#00000000"
+            android:offset="1.0"/>
+      </gradient>
+    </aapt:attr>
+  </path>
+  <path
+      android:fillColor="#FFFFFF"
+      android:fillType="nonZero"
+      android:pathData="M66.94,46.02L66.94,46.02C72.44,50.07 76,56.61 76,64L32,64C32,56.61 35.56,50.11 40.98,46.06L36.18,41.19C35.45,40.45 35.45,39.3 36.18,38.56C36.91,37.81 38.05,37.81 38.78,38.56L44.25,44.05C47.18,42.57 50.48,41.71 54,41.71C57.48,41.71 60.78,42.57 63.68,44.05L69.11,38.56C69.84,37.81 70.98,37.81 71.71,38.56C72.44,39.3 72.44,40.45 71.71,41.19L66.94,46.02ZM62.94,56.92C64.08,56.92 65,56.01 65,54.88C65,53.76 64.08,52.85 62.94,52.85C61.8,52.85 60.88,53.76 60.88,54.88C60.88,56.01 61.8,56.92 62.94,56.92ZM45.06,56.92C46.2,56.92 47.13,56.01 47.13,54.88C47.13,53.76 46.2,52.85 45.06,52.85C43.92,52.85 43,53.76 43,54.88C43,56.01 43.92,56.92 45.06,56.92Z"
+      android:strokeColor="#00000000"
+      android:strokeWidth="1"/>
+</vector>

android/samples/sample-texture-target/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,171 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportHeight="108"
+    android:viewportWidth="108">
+  <path
+      android:fillColor="#26A69A"
+      android:pathData="M0,0h108v108h-108z"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M9,0L9,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,0L19,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M29,0L29,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M39,0L39,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M49,0L49,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M59,0L59,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M69,0L69,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M79,0L79,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M89,0L89,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M99,0L99,108"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,9L108,9"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,19L108,19"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,29L108,29"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,39L108,39"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,49L108,49"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,59L108,59"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,69L108,69"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,79L108,79"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,89L108,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M0,99L108,99"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,29L89,29"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,39L89,39"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,49L89,49"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,59L89,59"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,69L89,69"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M19,79L89,79"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M29,19L29,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M39,19L39,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M49,19L49,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M59,19L59,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M69,19L69,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+  <path
+      android:fillColor="#00000000"
+      android:pathData="M79,19L79,89"
+      android:strokeColor="#33FFFFFF"
+      android:strokeWidth="0.8"/>
+</vector>

android/samples/sample-texture-target/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+  <background android:drawable="@drawable/ic_launcher_background"/>
+  <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+</adaptive-icon>

android/samples/sample-texture-target/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+  <background android:drawable="@drawable/ic_launcher_background"/>
+  <foreground android:drawable="@drawable/ic_launcher_foreground"/>
+</adaptive-icon>

android/samples/sample-texture-target/src/main/res/values/colors.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+  <color name="colorPrimary">#3F51B5</color>
+  <color name="colorPrimaryDark">#303F9F</color>
+  <color name="colorAccent">#FF4081</color>
+</resources>

android/samples/sample-texture-target/src/main/res/values/strings.xml

@@ -0,0 +1,3 @@
+<resources>
+  <string name="app_name">Texture Target</string>
+</resources>

android/samples/sample-texture-target/src/main/res/values/styles.xml

@@ -0,0 +1,8 @@
+<resources>
+
+  <!-- Base application theme. -->
+  <style name="AppTheme" parent="android:Theme.Material.Light.DarkActionBar">
+    <!-- Customize your theme here. -->
+  </style>
+
+</resources>

android/settings.gradle

@@ -12,10 +12,12 @@ include ':samples:sample-image-based-lighting'
 include ':samples:sample-lit-cube'
 include ':samples:sample-live-wallpaper'
 include ':samples:sample-material-builder'
+include ':samples:sample-material-instance-stress'
 include ':samples:sample-multi-view'
 include ':samples:sample-page-curl'
 include ':samples:sample-stream-test'
 include ':samples:sample-texture-view'
+include ':samples:sample-texture-target'
 include ':samples:sample-textured-object'
 include ':samples:sample-transparent-view'
 

build.sh

@@ -77,6 +77,10 @@ function print_help {
     echo "        meant for building the samples."
     echo "    -P"
     echo "        Enable perfetto traces on Android. Disabled by default on the Release build, enabled otherwise."
+    echo "    -y build_type"
+    echo "        Build the filament dependent tools (matc, resgen) separately from the project. This will set"
+    echo "        the tools as prebuilts that filament target will then use to build. The built_type option"
+    echo "        (debug|release) is meant to indicate the type of build of the resulting prebuilts."
     echo ""
     echo "Build types:"
     echo "    release"
@@ -154,7 +158,7 @@ function print_fgviewer_help {
 }
 
 # Unless explicitly specified, NDK version will be selected as highest available version within same major release chain
-FILAMENT_NDK_VERSION=${FILAMENT_NDK_VERSION:-$(cat `dirname $0`/build/common/versions | grep GITHUB_NDK_VERSION | sed s/GITHUB_NDK_VERSION=//g | cut -f 1 -d ".")}
+FILAMENT_NDK_VERSION=$(cat `dirname $0`/build/common/versions | grep GITHUB_NDK_VERSION | sed s/GITHUB_NDK_VERSION=//g | cut -f 1 -d ".")
 
 # Internal variables
 ISSUE_CLEAN=false
@@ -217,6 +221,11 @@ OSMESA_OPTION=""
 IOS_BUILD_SIMULATOR=false
 BUILD_UNIVERSAL_LIBRARIES=false
 
+ISSUE_SPLIT_BUILD=false
+SPLIT_BUILD_TYPE=""
+PREBUILT_TOOLS_DIR=""
+IMPORT_EXECUTABLES_DIR_OPTION="-DIMPORT_EXECUTABLES_DIR=out"
+
 BUILD_GENERATOR=Ninja
 BUILD_COMMAND=ninja
 BUILD_CUSTOM_TARGETS=
@@ -242,6 +251,37 @@ function build_clean_aggressive {
     git clean -qfX android
 }
 
+function build_tools_for_split_build {
+    local build_type_arg=$1
+    local lc_build_type=$(echo "${build_type_arg}" | tr '[:upper:]' '[:lower:]')
+    PREBUILT_TOOLS_DIR="out/prebuilt-tools-${lc_build_type}"
+
+    echo "Building tools for split build (${lc_build_type}) in ${PREBUILT_TOOLS_DIR}..."
+    mkdir -p "${PREBUILT_TOOLS_DIR}"
+
+    pushd "${PREBUILT_TOOLS_DIR}" > /dev/null
+
+    local lc_name=$(echo "${UNAME}" | tr '[:upper:]' '[:lower:]')
+    local architectures=""
+    if [[ "${lc_name}" == "darwin" ]]; then
+        if [[ "${BUILD_UNIVERSAL_LIBRARIES}" == "true" ]]; then
+            architectures="-DCMAKE_OSX_ARCHITECTURES=arm64;x86_64"
+        fi
+    fi
+
+    cmake \
+        -G "${BUILD_GENERATOR}" \
+        -DFILAMENT_EXPORT_PREBUILT_EXECUTABLES_DIR=${PREBUILT_TOOLS_DIR} \
+        -DCMAKE_BUILD_TYPE="${build_type_arg}" \
+        ${WEBGPU_OPTION} \
+        ${architectures} \
+        ../..
+
+    ${BUILD_COMMAND} ${WEB_HOST_TOOLS}
+
+    popd > /dev/null
+}
+
 function build_desktop_target {
     local lc_target=$(echo "$1" | tr '[:upper:]' '[:lower:]')
     local build_targets=$2
@@ -265,7 +305,7 @@ function build_desktop_target {
     if [[ ! -d "CMakeFiles" ]] || [[ "${ISSUE_CMAKE_ALWAYS}" == "true" ]]; then
         cmake \
             -G "${BUILD_GENERATOR}" \
-            -DIMPORT_EXECUTABLES_DIR=out \
+            ${IMPORT_EXECUTABLES_DIR_OPTION} \
             -DCMAKE_BUILD_TYPE="$1" \
             -DCMAKE_INSTALL_PREFIX="../${lc_target}/filament" \
             ${EGL_ON_LINUX_OPTION} \
@@ -331,7 +371,7 @@ function build_webgl_with_target {
         source "${EMSDK}/emsdk_env.sh"
         cmake \
             -G "${BUILD_GENERATOR}" \
-            -DIMPORT_EXECUTABLES_DIR=out \
+            ${IMPORT_EXECUTABLES_DIR_OPTION} \
             -DCMAKE_TOOLCHAIN_FILE="${EMSDK}/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake" \
             -DCMAKE_BUILD_TYPE="$1" \
             -DCMAKE_INSTALL_PREFIX="../webgl-${lc_target}/filament" \
@@ -404,7 +444,7 @@ function build_android_target {
     if [[ ! -d "CMakeFiles" ]] || [[ "${ISSUE_CMAKE_ALWAYS}" == "true" ]]; then
         cmake \
             -G "${BUILD_GENERATOR}" \
-            -DIMPORT_EXECUTABLES_DIR=out \
+            ${IMPORT_EXECUTABLES_DIR_OPTION} \
             -DCMAKE_BUILD_TYPE="$1" \
             -DFILAMENT_NDK_VERSION="${FILAMENT_NDK_VERSION}" \
             -DCMAKE_INSTALL_PREFIX="../android-${lc_target}/filament" \
@@ -516,11 +556,14 @@ function build_android {
         archive_android "Release"
     fi
 
+    local root_dir=$(pwd)
+
     pushd android > /dev/null
 
     if [[ "${ISSUE_DEBUG_BUILD}" == "true" ]]; then
         ./gradlew \
             -Pcom.google.android.filament.dist-dir=../out/android-debug/filament \
+            -Pcom.google.android.filament.tools-dir=${root_dir}/out/debug/filament \
             -Pcom.google.android.filament.abis=${ABI_GRADLE_OPTION} \
             ${VULKAN_ANDROID_GRADLE_OPTION} \
             ${WEBGPU_ANDROID_GRADLE_OPTION} \
@@ -533,6 +576,7 @@ function build_android {
 
         ./gradlew \
             -Pcom.google.android.filament.dist-dir=../out/android-debug/filament \
+            -Pcom.google.android.filament.tools-dir=${root_dir}/out/debug/filament \
             -Pcom.google.android.filament.abis=${ABI_GRADLE_OPTION} \
             ${WEBGPU_ANDROID_GRADLE_OPTION} \
             :filamat-android:assembleDebug
@@ -541,6 +585,7 @@ function build_android {
             for sample in ${ANDROID_SAMPLES}; do
                 ./gradlew \
                     -Pcom.google.android.filament.dist-dir=../out/android-debug/filament \
+                   -Pcom.google.android.filament.tools-dir=${root_dir}/out/debug/filament \
                     -Pcom.google.android.filament.abis=${ABI_GRADLE_OPTION} \
                     ${MATOPT_GRADLE_OPTION} \
                     :samples:${sample}:assembleDebug
@@ -573,6 +618,7 @@ function build_android {
     if [[ "${ISSUE_RELEASE_BUILD}" == "true" ]]; then
         ./gradlew \
             -Pcom.google.android.filament.dist-dir=../out/android-release/filament \
+            -Pcom.google.android.filament.tools-dir=${root_dir}/out/release/filament \
             -Pcom.google.android.filament.abis=${ABI_GRADLE_OPTION} \
             ${VULKAN_ANDROID_GRADLE_OPTION} \
             ${WEBGPU_ANDROID_GRADLE_OPTION} \
@@ -585,6 +631,7 @@ function build_android {
 
         ./gradlew \
             -Pcom.google.android.filament.dist-dir=../out/android-release/filament \
+            -Pcom.google.android.filament.tools-dir=${root_dir}/out/release/filament \
             -Pcom.google.android.filament.abis=${ABI_GRADLE_OPTION} \
             ${WEBGPU_ANDROID_GRADLE_OPTION} \
             :filamat-android:assembleRelease
@@ -593,6 +640,7 @@ function build_android {
             for sample in ${ANDROID_SAMPLES}; do
                 ./gradlew \
                     -Pcom.google.android.filament.dist-dir=../out/android-release/filament \
+                    -Pcom.google.android.filament.tools-dir=${root_dir}/out/release/filament \
                     -Pcom.google.android.filament.abis=${ABI_GRADLE_OPTION} \
                     ${MATOPT_GRADLE_OPTION} \
                     :samples:${sample}:assembleRelease
@@ -638,7 +686,7 @@ function build_ios_target {
     if [[ ! -d "CMakeFiles" ]] || [[ "${ISSUE_CMAKE_ALWAYS}" == "true" ]]; then
         cmake \
             -G "${BUILD_GENERATOR}" \
-            -DIMPORT_EXECUTABLES_DIR=out \
+            ${IMPORT_EXECUTABLES_DIR_OPTION} \
             -DCMAKE_BUILD_TYPE="$1" \
             -DCMAKE_INSTALL_PREFIX="../ios-${lc_target}/filament" \
             -DIOS_ARCH="${arch}" \
@@ -810,7 +858,7 @@ function check_debug_release_build {
 
 pushd "$(dirname "$0")" > /dev/null
 
-while getopts ":hacCfgimp:q:uvWslwedtk:bVx:S:X:P" opt; do
+while getopts ":hacCfgimp:q:uvWslwedtk:bVx:S:X:Py:" opt; do
     case ${opt} in
         h)
             print_help
@@ -979,6 +1027,20 @@ while getopts ":hacCfgimp:q:uvWslwedtk:bVx:S:X:P" opt; do
             ;;
         X)  OSMESA_OPTION="-DFILAMENT_OSMESA_PATH=${OPTARG}"
             ;;
+        y)
+            ISSUE_SPLIT_BUILD=true
+            SPLIT_BUILD_TYPE=${OPTARG}
+            case $(echo "${SPLIT_BUILD_TYPE}" | tr '[:upper:]' '[:lower:]') in
+                debug|release)
+                    ;;
+                *)
+                    echo "Unknown build type for -y: ${SPLIT_BUILD_TYPE}"
+                    echo "Build type must be one of [debug|release]"
+                    echo ""
+                    exit 1
+                    ;;
+            esac
+            ;;
         \?)
             echo "Invalid option: -${OPTARG}" >&2
             echo ""
@@ -1013,6 +1075,13 @@ done
 
 validate_build_command
 
+if [[ "${ISSUE_SPLIT_BUILD}" == "true" ]]; then
+    # Capitalize first letter of SPLIT_BUILD_TYPE
+    SPLIT_BUILD_TYPE_CAPITALIZED="$(echo ${SPLIT_BUILD_TYPE:0:1} | tr '[:lower:]' '[:upper:]')${SPLIT_BUILD_TYPE:1}"
+    build_tools_for_split_build "${SPLIT_BUILD_TYPE_CAPITALIZED}"
+    IMPORT_EXECUTABLES_DIR_OPTION="-DFILAMENT_IMPORT_PREBUILT_EXECUTABLES_DIR=${PREBUILT_TOOLS_DIR}"
+fi
+
 if [[ "${ISSUE_CLEAN}" == "true" ]]; then
     build_clean
 fi

build/android/build.sh

@@ -18,8 +18,8 @@ if [[ "$GITHUB_WORKFLOW" ]]; then
     fi
 fi
 
-# Unless explicitly specified, NDK version will be set to match exactly the required one
-FILAMENT_NDK_VERSION=${GITHUB_NDK_VERSION:-27.0.11718014}
+# Unless explicitly specified, NDK version will be selected as highest available version within same major release chain
+FILAMENT_NDK_VERSION=$(cat `dirname $0`/../common/versions | grep GITHUB_NDK_VERSION | sed s/GITHUB_NDK_VERSION=//g)
 
 (! grep "${FILAMENT_NDK_VERSION}" `dirname $0`/../../android/build.gradle > /dev/null) &&
     echo "Mismatch of NDK versions: want ${FILAMENT_NDK_VERSION} and not found in android/build.gradle" &&

build/common/test_list.txt

@@ -1,6 +1,5 @@
 libs/viewer/test_settings
 filament/test/test_filament --gtest_filter=-FilamentTest.FroxelData:FilamentExposureWithEngineTest.SetExposure:FilamentExposureWithEngineTest.ComputeEV100:RenderingTest.*
-filament/test/test_material_parser
 libs/math/test_math
 libs/image/test_image compare libs/image/tests/reference/
 libs/utils/test_utils

build/common/versions

@@ -3,7 +3,7 @@ GITHUB_CMAKE_VERSION=3.22.1
 GITHUB_NINJA_VERSION=1.10.2
 GITHUB_MESA_VERSION=24.2.1
 GITHUB_LLVM_VERSION=16
-GITHUB_NDK_VERSION=27.0.11718014
+GITHUB_NDK_VERSION=29.0.14206865
 GITHUB_EMSDK_VERSION=3.1.60
 GITHUB_VULKANSDK_VERSION=1.4.321.0
-GITHUB_GLTF_SAMPLE_ASSETS_COMMIT=d441dfdb87413ff412c620849a649d61789a470f
+GITHUB_GLTF_SAMPLE_ASSETS_COMMIT=d441dfdb87413ff412c620849a649d61789a470f

build/toolchain-aarch64-linux-android.cmake

@@ -75,7 +75,7 @@ set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
 #   C_FLAGS += -Wl,-pie
 #   CXX_FLAGS += -lstdc++
 
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIE -mcpu=cortex-a57" CACHE STRING "Toolchain CFLAGS")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fPIE -march=armv8-a -mtune=cortex-a78" CACHE STRING "Toolchain CFLAGS")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_C_FLAGS}" CACHE STRING "Toolchain CXXFLAGS")
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fPIE -pie -static-libstdc++" CACHE STRING "Toolchain LDFLAGS")
 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -static-libstdc++" CACHE STRING "Toolchain LDFLAGS")

build/toolchain-arm7-linux-android.cmake

@@ -87,7 +87,7 @@ set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
 # for hardfp: CFLAGS must have -mhard-float
 #             LDFLAGS must have -Wl,--no-warn-mismatch
 #
-set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} -mthumb -march=armv7-a -mcpu=cortex-a15 -mfloat-abi=softfp -mfpu=neon-vfpv4 -fPIE" CACHE STRING "Toolchain CFLAGS")
+set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} -mthumb -march=armv7-a -mfloat-abi=softfp -mfpu=neon-vfpv4 -fPIE" CACHE STRING "Toolchain CFLAGS")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_C_FLAGS}" CACHE STRING "Toolchain CXXFLAGS")
 set(CMAKE_EXE_LINKER_FLAGS    "${CMAKE_EXE_LINKER_FLAGS}    -march=armv7-a -Wl,--no-warn-mismatch -L${TOOLCHAIN}/arm-linux-androideabi/lib/armv7-a -static-libstdc++ -fPIE -pie" CACHE STRING "Toolchain LDFLAGS")
 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -march=armv7-a -Wl,--no-warn-mismatch -L${TOOLCHAIN}/arm-linux-androideabi/lib/armv7-a -static-libstdc++" CACHE STRING "Toolchain LDFLAGS")

docs/build/maven_release.html

@@ -165,8 +165,8 @@ Portal</a>.</p>
 <p>To publish under the <code>com.google.android</code> namespace, you'll also need to email
 <code>central-support@sonatype.com</code> with your account information to request access.</p>
 <p>Then, generate a user token through the Sonatype website. Navigate to
-<a href="https://central.sonatype.com/account">https://central.sonatype.com/account</a> and select <strong>Generate
-User Token</strong>.</p>
+<a href="https://central.sonatype.com/usertoken">https://central.sonatype.com/usertoken</a>
+and select <strong>Generate User Token</strong>.</p>
 <p>Finally, add the generated token credentials to <code>~/.gradle/gradle.properties</code>. (Note: these are
 different from the credentials used to log into your Sonatype account):</p>
 <pre><code class="language-gradle"># Generated Sonatype token

docs/dup/bluevk.html

@@ -180,7 +180,7 @@ rm -r Vulkan-Headers-1.3.232 v1.3.232.zip
                                 <i class="fa fa-angle-left"></i>
                             </a>
 
-                            <a rel="next prefetch" href="../dup/filamat.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
+                            <a rel="next prefetch" href="../dup/fgviewer.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
                                 <i class="fa fa-angle-right"></i>
                             </a>
 
@@ -194,7 +194,7 @@ rm -r Vulkan-Headers-1.3.232 v1.3.232.zip
                         <i class="fa fa-angle-left"></i>
                     </a>
 
-                    <a rel="next prefetch" href="../dup/filamat.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
+                    <a rel="next prefetch" href="../dup/fgviewer.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
                         <i class="fa fa-angle-right"></i>
                     </a>
             </nav>

docs/dup/building.html

@@ -200,6 +200,12 @@ inside the Filament source tree.</p>
 force a clean build by adding the <code>-c</code> flag in that case.</p>
 <p>To install the libraries and executables in <code>out/debug/</code> and <code>out/release/</code>, add the <code>-i</code> flag.
 The script offers more features described by executing <code>build.sh -h</code>.</p>
+<p>For more specialized options, please also consider the following pages:</p>
+<ul>
+<li><code>-d</code>: <a href="https://google.github.io/filament/dup/matdbg.html"><code>matdbg</code></a></li>
+<li><code>-t</code>: <a href="https://google.github.io/filament/dup/fgviewer.html"><code>fgviewer</code></a></li>
+<li><code>-b</code> and <code>-y</code>: <a href="https://google.github.io/filament/notes/asan_ubsan.html">ASAN/UBSAN builds</a></li>
+</ul>
 <h3 id="filament-specific-cmake-options"><a class="header" href="#filament-specific-cmake-options">Filament-specific CMake Options</a></h3>
 <p>The following CMake options are boolean options specific to Filament:</p>
 <ul>
@@ -434,7 +440,7 @@ to create a quick localhost server:</p>
 <p>Alternatively, if you have node installed you can use the
 <a href="https://www.npmjs.com/package/live-server">live-server</a> package, which automatically refreshes the
 web page when it detects a change.</p>
-<p>Each sample app has its own handwritten html file. Additionally the server folder contains assets
+<p>Each sample app has its own handwritten html file. Additionally, the server folder contains assets
 such as meshes, textures, and materials.</p>
 <h2 id="running-the-native-samples"><a class="header" href="#running-the-native-samples">Running the native samples</a></h2>
 <p>The <code>samples/</code> directory contains several examples of how to use Filament with SDL2.</p>

docs/dup/code_style.html

@@ -179,7 +179,7 @@ Google code style and is derived from the Java code style, but not quite.</p>
 <li>class access modifiers are not indented</li>
 <li>last line of <code>.cpp</code> or <code>.h</code> file must be an empty line</li>
 </ul>
-<pre><code>for (int i = 0; i &lt; max; i++) {
+<pre><code class="language-c++">for (int i = 0; i &lt; max; i++) {
 }
 
 class Foo {
@@ -227,11 +227,23 @@ src/data.inc
 <li><code>public</code> class attributes <em>are not</em> prefixed</li>
 <li>class attributes and methods are lower camelcase</li>
 </ul>
-<pre><code>extern int gGlobalWarming;
+<pre><code class="language-c++">extern int gGlobalWarming;
 
 class FooBar {
 public:
-    void methodName();
+    FooBar(int attributeName, int sizeInBytes)
+            : mAttributeName(attributeName),
+              sizeInBytes(sizeInBytes) {}
+
+    void reallyLongMethodNameWithLotsOfArguments(bool argument1,
+            int someSecondArgument, int bestArgument) {
+        std::pair&lt;bool, int&gt; pair = {
+            argument1,
+            argument2,
+        };
+        // etc
+    }
+
     int sizeInBytes;
 private:
     int mAttributeName;
@@ -248,7 +260,7 @@ private:
 <li>always include the copyright notice at the top of every file</li>
 <li>make sure the date is correct</li>
 </ul>
-<pre><code>/*
+<pre><code class="language-c++">/*
  * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -293,7 +305,7 @@ conversely containers and algorithms are not allowed. There are exceptions such
 </li>
 </ul>
 <p><em>Sorting the headers is important to help catching missing <code>#include</code> directives.</em></p>
-<pre><code>/*
+<pre><code class="language-c++">/*
  * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -336,7 +348,7 @@ from other string types.</li>
 <ul>
 <li>Use <code>auto</code> only when the type appears on the same line or with iterators and lambdas.</li>
 </ul>
-<pre><code>auto foo = new Foo();
+<pre><code class="language-c++">auto foo = new Foo();
 for (auto&amp; i : collection) { }
 </code></pre>
 

docs/dup/fgviewer.html

@@ -0,0 +1,345 @@
+<!DOCTYPE HTML>
+<html lang="en" class="light sidebar-visible" dir="ltr">
+    <head>
+        <!-- Book generated using mdBook -->
+        <meta charset="UTF-8">
+        <title>fgviewer - Filament</title>
+
+
+        <!-- Custom HTML head -->
+
+        <meta name="description" content="">
+        <meta name="viewport" content="width=device-width, initial-scale=1">
+        <meta name="theme-color" content="#ffffff">
+
+        <link rel="shortcut icon" href="../favicon.png">
+        <link rel="stylesheet" href="../css/variables.css">
+        <link rel="stylesheet" href="../css/general.css">
+        <link rel="stylesheet" href="../css/chrome.css">
+
+        <!-- Fonts -->
+        <link rel="stylesheet" href="../FontAwesome/css/font-awesome.css">
+        <link rel="stylesheet" href="../fonts/fonts.css">
+
+        <!-- Highlight.js Stylesheets -->
+        <link rel="stylesheet" href="../highlight.css">
+        <link rel="stylesheet" href="../tomorrow-night.css">
+        <link rel="stylesheet" href="../ayu-highlight.css">
+
+        <!-- Custom theme stylesheets -->
+
+        <!-- MathJax -->
+        <script async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
+
+        <!-- Provide site root to javascript -->
+        <script>
+            var path_to_root = "../";
+            var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "light" : "light";
+        </script>
+        <!-- Start loading toc.js asap -->
+        <script src="../toc.js"></script>
+    </head>
+    <body>
+    <div id="body-container">
+        <!-- Work around some values being stored in localStorage wrapped in quotes -->
+        <script>
+            try {
+                var theme = localStorage.getItem('mdbook-theme');
+                var sidebar = localStorage.getItem('mdbook-sidebar');
+
+                if (theme.startsWith('"') && theme.endsWith('"')) {
+                    localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
+                }
+
+                if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
+                    localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
+                }
+            } catch (e) { }
+        </script>
+
+        <!-- Set the theme before any content is loaded, prevents flash -->
+        <script>
+            var theme;
+            try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
+            if (theme === null || theme === undefined) { theme = default_theme; }
+            const html = document.documentElement;
+            html.classList.remove('light')
+            html.classList.add(theme);
+            html.classList.add("js");
+        </script>
+
+        <input type="checkbox" id="sidebar-toggle-anchor" class="hidden">
+
+        <!-- Hide / unhide sidebar before it is displayed -->
+        <script>
+            var sidebar = null;
+            var sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
+            if (document.body.clientWidth >= 1080) {
+                try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
+                sidebar = sidebar || 'visible';
+            } else {
+                sidebar = 'hidden';
+            }
+            sidebar_toggle.checked = sidebar === 'visible';
+            html.classList.remove('sidebar-visible');
+            html.classList.add("sidebar-" + sidebar);
+        </script>
+
+        <nav id="sidebar" class="sidebar" aria-label="Table of contents">
+            <div style="display:flex;align-items:center;justify-content:center">
+                <img class="flogo" src="../images/filament_logo_small.png"></img>
+            </div>
+            <!-- populated by js -->
+            <mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
+            <noscript>
+                <iframe class="sidebar-iframe-outer" src="../toc.html"></iframe>
+            </noscript>
+            <div id="sidebar-resize-handle" class="sidebar-resize-handle">
+                <div class="sidebar-resize-indicator"></div>
+            </div>
+        </nav>
+
+        <div id="page-wrapper" class="page-wrapper">
+
+            <div class="page">
+                <div id="menu-bar-hover-placeholder"></div>
+                <div id="menu-bar" class="menu-bar sticky">
+                    <div class="left-buttons">
+                        <label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
+                            <i class="fa fa-bars"></i>
+                        </label>
+                        <!-- Filament: disable themes because the markdeep part does not look good for dark themes -->
+                        <!--
+                        <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
+                            <i class="fa fa-paint-brush"></i>
+                        </button>
+                        <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
+                            <li role="none"><button role="menuitem" class="theme" id="light">Light</button></li>
+                            <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
+                            <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
+                            <li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
+                            <li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
+                        </ul>
+                        -->
+                        <button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
+                            <i class="fa fa-search"></i>
+                        </button>
+                    </div>
+
+                    <h1 class="menu-title">Filament</h1>
+
+                    <div class="right-buttons">
+                        <a href="https://github.com/google/filament" title="Git repository" aria-label="Git repository">
+                            <i id="git-repository-button" class="fa fa-github"></i>
+                        </a>
+
+                    </div>
+                </div>
+
+                <div id="search-wrapper" class="hidden">
+                    <form id="searchbar-outer" class="searchbar-outer">
+                        <input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
+                    </form>
+                    <div id="searchresults-outer" class="searchresults-outer hidden">
+                        <div id="searchresults-header" class="searchresults-header"></div>
+                        <ul id="searchresults">
+                        </ul>
+                    </div>
+                </div>
+
+                <!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
+                <script>
+                    document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
+                    document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
+                    Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
+                        link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
+                    });
+                </script>
+
+                <div id="content" class="content">
+                    <main>
+                        <h1 id="fgviewer"><a class="header" href="#fgviewer">fgviewer</a></h1>
+<ol>
+<li><a href="#capabilities">Capabilities</a></li>
+<li><a href="#setup-for-desktop">Setup for Desktop</a></li>
+<li><a href="#setup-for-android">Setup for Android</a></li>
+<li><a href="#debugger-usage">Debugger Usage</a></li>
+<li><a href="#architecture-overview">Architecture Overview</a></li>
+<li><a href="#c-server">C++ Server</a></li>
+<li><a href="#javascript-client">JavaScript Client</a></li>
+<li><a href="#http-requests">HTTP Requests</a></li>
+<li><a href="#wish-list">Wish List</a></li>
+</ol>
+<h2 id="capabilities"><a class="header" href="#capabilities">Capabilities</a></h2>
+<p>fgviewer is a library and web application for real-time visualization of the frame graph in Filament.
+It displays active passes and resource usage, providing insights into the rendering pipeline.</p>
+<h2 id="setup-for-desktop"><a class="header" href="#setup-for-desktop">Setup for Desktop</a></h2>
+<p>When using the easy build script, include the <code>-t</code> argument. For example:</p>
+<pre><code>./build.sh -ft debug gltf_viewer
+</code></pre>
+<p>The <code>t</code> enables a CMake option called <code>FILAMENT_ENABLE_FGVIEWER</code> and the <code>f</code> ensures that CMake gets
+re-run so that the option is honored.</p>
+<p>Next, set an environment variable as follows. In Windows, use <code>set</code> instead of <code>export</code>.</p>
+<pre><code>export FILAMENT_FGVIEWER_PORT=8050
+</code></pre>
+<p>Next, launch any app that links against a debug build of a Filament and point your web browser to
+http://localhost:8050. Skip ahead to <strong>Debugger Usage</strong>.</p>
+<h2 id="setup-for-android"><a class="header" href="#setup-for-android">Setup for Android</a></h2>
+<p>Rebuild Filament for Android after enabling a CMake option called <code>FILAMENT_ENABLE_FGVIEWER</code>. Note that
+CMake is invoked from several places for Android (both gradle and our easy build script), so one
+pragmatic and reliable way of doing this is to simply hack <code>CMakeLists.txt</code> and
+<code>filament-android/CMakeLists.txt</code> by unconditionally setting <code>FILAMENT_ENABLE_FGVIEWER</code> to <code>ON</code>.</p>
+<p>After rebuilding Filament with the option enabled, ensure that internet permissions are enabled in
+your app by adding the following into your manifest as a child of the <code>&lt;manifest&gt;</code> element.</p>
+<pre><code>&lt;uses-permission android:name="android.permission.INTERNET" /&gt;
+</code></pre>
+<p>Now launch your app as usual. The Filament Engine sets up a server that is hardcoded to listen to
+port <code>8085</code>. Next, you will need to forward your device's TCP port <code>8085</code> to your host port of choice.
+For example, to forward the fgviewer server on your device to port <code>8085</code> on your host machine, do the
+following:</p>
+<pre><code>adb forward tcp:8085 tcp:8085
+</code></pre>
+<p>This lets you go to http://localhost:8085 in Chrome on your host machine.</p>
+<h2 id="debugger-usage"><a class="header" href="#debugger-usage">Debugger Usage</a></h2>
+<p>After opening the fgviewer page in your browser, you can see the active views are on the left panel.
+Then you can select any of them to see the active passes and resources for that view.</p>
+<p align="center">
+  <img width="600px" src=https://github.com/user-attachments/assets/2d31767f-fc25-4f17-8c14-528fe5c6b698>
+</p>
+<h2 id="architecture-overview"><a class="header" href="#architecture-overview">Architecture Overview</a></h2>
+<p align="center">
+  <img width="450" src=https://github.com/user-attachments/assets/537ebb89-6ad0-4b93-bbeb-207d4fe9ec5a>
+</p>
+<p>The fgviewer library has two parts: a C++ server and a JavaScript client. The C++ server is
+responsible for instancing a <a href="https://github.com/civetweb/civetweb">civetweb</a> context that handles HTTP requests. The
+JavaScript client is a small web app that contains a view into an in-browser database of framegraphs.</p>
+<p>When a new connection is established, the client asks the server for a list of framegraphs
+in order to populate its in-browser database. If the connection is lost (e.g. if the app crashes),
+then the database stays intact and the web app is still functional.</p>
+<h2 id="c-server"><a class="header" href="#c-server">C++ Server</a></h2>
+<p>The civetweb server is wrapped by our <code>DebugServer</code> class, which provides a public interface consisting of
+a few methods invoked by the Filament engine.</p>
+<p>Since each view corresponds to a frame graph, the engine should notify <code>DebugServer</code> of any changes to the views
+on the engine side.</p>
+<ul>
+<li><strong>createView</strong> Notifies the debugger that a new view has been created.</li>
+<li><strong>updateView</strong> Notifies the debugger of updates to an existing view.</li>
+<li><strong>destroyView</strong> Notifies the debugger that a view is being removed.</li>
+</ul>
+<h2 id="javascript-client"><a class="header" href="#javascript-client">JavaScript Client</a></h2>
+<p>The web app is built using LitElement, a lightweight library for creating Web Components. Our goal is to keep the code simple and modern, avoiding frameworks like React or Angular.</p>
+<p>The app presents a view over a pseudo-database, which is essentially a global variable holding a dictionary that maps frame graph ids to objects following the JSON structure described below.</p>
+<h2 id="http-requests"><a class="header" href="#http-requests">HTTP requests</a></h2>
+<p>The server responds to the following GET requests by returning a JSON blob. The <code>{id}</code> in these
+requests is a concept specific to fgviewer (not Filament) which is an 8-digit hex string for identifying frame graphs.</p>
+<hr />
+<p><code>/api/framegraphs</code></p>
+<p>Returns an array containing all framegraphs in an app. Example:</p>
+<pre><code class="language-json">[{
+    "fgid": "00000000",
+    "viewName": "Main View",
+    "passes": [{
+        "name": "shadow pass",
+        "reads": [],
+        "writes": ["0"]
+    }],
+    "resources": [{
+        "id": "0",
+        "name": "shadowmap",
+        "properties": [{"resolution": "256x256"}, {"is_subresource": "false"}]
+    }]
+},
+{
+    "fgid": "00000001",
+    "viewName": "UI view",
+    ...
+}]
+</code></pre>
+<hr />
+<p><code>/api/framegraph?fg={id}</code></p>
+<p>Returns a specific framegraph info. Example:</p>
+<pre><code class="language-json">{
+  "fgid": "00000000",
+  "viewName": "Main View",
+  "passes": [{
+    "name": "shadow pass",
+    "reads": [],
+    "writes": ["0"]
+  }],
+  "resources": [{
+    "id": "0",
+    "name": "shadowmap",
+    "properties": [{"resolution": "256x256"}, {"is_subresource": "false"}]
+  }]
+}
+</code></pre>
+<hr />
+<p><code>/api/status</code></p>
+<p>Returns one of the below:</p>
+<ul>
+<li><code>0</code>: first time connected</li>
+<li><code>1</code>: no-op</li>
+<li><code>{fgid}</code>: the corresponding frame graph has an update
+<ul>
+<li>Then the web view can request for the actual info using the previous api</li>
+</ul>
+</li>
+</ul>
+<p>If the request gets timeout, the web page show disconnected to the user.</p>
+<hr />
+<h2 id="wish-list"><a class="header" href="#wish-list">Wish List</a></h2>
+<ul>
+<li>Display the texture contents on the webview</li>
+</ul>
+
+                    </main>
+
+                    <nav class="nav-wrapper" aria-label="Page navigation">
+                        <!-- Mobile navigation buttons -->
+                            <a rel="prev" href="../dup/bluevk.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
+                                <i class="fa fa-angle-left"></i>
+                            </a>
+
+                            <a rel="next prefetch" href="../dup/filamat.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
+                                <i class="fa fa-angle-right"></i>
+                            </a>
+
+                        <div style="clear: both"></div>
+                    </nav>
+                </div>
+            </div>
+
+            <nav class="nav-wide-wrapper" aria-label="Page navigation">
+                    <a rel="prev" href="../dup/bluevk.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
+                        <i class="fa fa-angle-left"></i>
+                    </a>
+
+                    <a rel="next prefetch" href="../dup/filamat.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
+                        <i class="fa fa-angle-right"></i>
+                    </a>
+            </nav>
+
+        </div>
+
+
+
+
+        <script>
+            window.playground_copyable = true;
+        </script>
+
+
+        <script src="../elasticlunr.min.js"></script>
+        <script src="../mark.min.js"></script>
+        <script src="../searcher.js"></script>
+
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+        <script src="../highlight.js"></script>
+        <script src="../book.js"></script>
+
+        <!-- Custom JS scripts -->
+
+
+    </div>
+    </body>
+</html>

docs/dup/filamat.html

@@ -336,7 +336,7 @@ void material(inout MaterialInputs material) {
 
                     <nav class="nav-wrapper" aria-label="Page navigation">
                         <!-- Mobile navigation buttons -->
-                            <a rel="prev" href="../dup/bluevk.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
+                            <a rel="prev" href="../dup/fgviewer.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
                                 <i class="fa fa-angle-left"></i>
                             </a>
 
@@ -350,7 +350,7 @@ void material(inout MaterialInputs material) {
             </div>
 
             <nav class="nav-wide-wrapper" aria-label="Page navigation">
-                    <a rel="prev" href="../dup/bluevk.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
+                    <a rel="prev" href="../dup/fgviewer.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
                         <i class="fa fa-angle-left"></i>
                     </a>
 

docs/dup/intro.html

@@ -181,7 +181,7 @@ important for <code>matc</code> (material compiler).</p>
 }
 
 dependencies {
-    implementation 'com.google.android.filament:filament-android:1.65.0'
+    implementation 'com.google.android.filament:filament-android:1.68.0'
 }
 </code></pre>
 <p>Here are all the libraries available in the group <code>com.google.android.filament</code>:</p>
@@ -196,7 +196,7 @@ dependencies {
 </div>
 <h3 id="ios"><a class="header" href="#ios">iOS</a></h3>
 <p>iOS projects can use CocoaPods to install the latest release:</p>
-<pre><code class="language-shell">pod 'Filament', '~&gt; 1.65.0'
+<pre><code class="language-shell">pod 'Filament', '~&gt; 1.68.0'
 </code></pre>
 <h2 id="documentation"><a class="header" href="#documentation">Documentation</a></h2>
 <ul>