diff --git a/CMakeLists.txt b/CMakeLists.txt
index 649577b396c7..b8462d29f1e5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -525,11 +525,14 @@ else()
     option(FILAMENT_BUILD_FILAMAT "Build filamat and JNI buildings" OFF)
 endif()
 
-# By default, link in matdbg for Desktop + Debug only since it pulls in filamat and a web server.
+# By default, link in matdbg/fgviewer for Desktop + Debug only since it pulls in filamat and a web server.
 if (CMAKE_BUILD_TYPE STREQUAL "Debug" AND IS_HOST_PLATFORM)
     option(FILAMENT_ENABLE_MATDBG "Enable the material debugger" ON)
+    # TODO: Uncomment below when fgviewer is ready
+    # option(FILAMENT_ENABLE_FGVIEWER "Enable the frame graph viewer" ON)
 else()
     option(FILAMENT_ENABLE_MATDBG "Enable the material debugger" OFF)
+    option(FILAMENT_ENABLE_FGVIEWER "Enable the frame graph viewer" OFF)
 endif()
 
 # Only optimize materials in Release mode (so error message lines match the source code)
@@ -778,6 +781,11 @@ if (FILAMENT_BUILD_FILAMAT OR IS_HOST_PLATFORM)
     if (FILAMENT_ENABLE_MATDBG OR IS_HOST_PLATFORM)
         add_subdirectory(${LIBRARIES}/matdbg)
     endif()
+
+    # TODO: Uncomment below when fgviewer is ready
+    # if (FILAMENT_ENABLE_FGVIEWER OR IS_HOST_PLATFORM)
+    #     add_subdirectory(${LIBRARIES}/fgviewer)
+    # endif()
 endif()
 
 if (FILAMENT_SUPPORTS_VULKAN)
diff --git a/README.md b/README.md
index d3c1dc1b2b58..5cd0c006c517 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ repositories {
 }
 
 dependencies {
-    implementation 'com.google.android.filament:filament-android:1.56.5'
+    implementation 'com.google.android.filament:filament-android:1.56.6'
 }
 ```
 
@@ -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', '~> 1.56.5'
+pod 'Filament', '~> 1.56.6'
 ```
 
 ## Documentation
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index a57b43591f42..8ff3e6507bf6 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -7,6 +7,10 @@ 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).
 
+## v1.56.6
+
+fix crash: the 'target_node' of Animation Channel may be nullpointer.
+
 ## v1.56.5
 
 
diff --git a/android/build.gradle b/android/build.gradle
index 970e41fb90f9..293387890eea 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -11,6 +11,9 @@
 // com.google.android.filament.exclude-vulkan
 //     When set, support for Vulkan will be excluded.
 //
+// com.google.android.filament.fgviewer
+//     When set, enables fgviewer
+//
 // com.google.android.filament.matdbg
 //     When set, enables matdbg
 //
@@ -61,6 +64,11 @@ buildscript {
             .gradleProperty("com.google.android.filament.exclude-vulkan")
             .isPresent()
 
+    // TODO: Uncomment below when fgviewer is ready
+    // def fgviewer = providers
+    //         .gradleProperty("com.google.android.filament.fgviewer")
+    //         .isPresent()
+
     def matdbg = providers
             .gradleProperty("com.google.android.filament.matdbg")
             .isPresent()
@@ -115,6 +123,8 @@ buildscript {
         "-DANDROID_STL=c++_static",
         "-DFILAMENT_DIST_DIR=${filamentPath}".toString(),
         "-DFILAMENT_SUPPORTS_VULKAN=${excludeVulkan ? 'OFF' : 'ON'}".toString(),
+        // TODO: Uncomment below when fgviewer is ready
+        // "-DFILAMENT_ENABLE_FGVIEWER=${fgviewer ? 'ON' : 'OFF'}".toString(),
         "-DFILAMENT_ENABLE_MATDBG=${matdbg ? 'ON' : 'OFF'}".toString(),
         "-DFILAMENT_DISABLE_MATOPT=${matnopt ? 'ON' : 'OFF'}".toString()
     ]
diff --git a/android/filament-android/CMakeLists.txt b/android/filament-android/CMakeLists.txt
index 7f3122f64565..21da97e6b70b 100644
--- a/android/filament-android/CMakeLists.txt
+++ b/android/filament-android/CMakeLists.txt
@@ -2,6 +2,8 @@ cmake_minimum_required(VERSION 3.19)
 project(filament-android)
 
 option(FILAMENT_SUPPORTS_VULKAN "Enables Vulkan on Android" OFF)
+# TODO: Uncomment below when fgviewer is ready
+# option(FILAMENT_ENABLE_FGVIEWER "Enables Frame Graph Viewer" OFF)
 option(FILAMENT_ENABLE_MATDBG "Enables Material debugger" OFF)
 option(FILAMENT_DISABLE_MATOPT "Disables material optimizations" OFF)
 
@@ -51,6 +53,13 @@ add_library(smol-v STATIC IMPORTED)
 set_target_properties(smol-v PROPERTIES IMPORTED_LOCATION
         ${FILAMENT_DIR}/lib/${ANDROID_ABI}/libsmol-v.a)
 
+# TODO: Uncomment below when fgviewer is ready
+# if (FILAMENT_ENABLE_FGVIEWER)
+#     add_library(fgviewer STATIC IMPORTED)
+#     set_target_properties(fgviewer PROPERTIES IMPORTED_LOCATION
+#             ${FILAMENT_DIR}/lib/${ANDROID_ABI}/libfgviewer.a)
+# endif()
+
 if (FILAMENT_ENABLE_MATDBG)
     add_library(matdbg STATIC IMPORTED)
     set_target_properties(matdbg PROPERTIES IMPORTED_LOCATION
@@ -117,6 +126,8 @@ target_link_libraries(filament-jni
     # libgeometry is PUBLIC because gltfio uses it.
     PUBLIC geometry
 
+    # TODO: Uncomment below when fgviewer is ready
+    # $<$<STREQUAL:${FILAMENT_ENABLE_FGVIEWER},ON>:fgviewer>
     $<$<STREQUAL:${FILAMENT_ENABLE_MATDBG},ON>:matdbg>
     $<$<STREQUAL:${FILAMENT_ENABLE_MATDBG},ON>:filamat>
     $<$<STREQUAL:${FILAMENT_SUPPORTS_VULKAN},ON>:bluevk>
diff --git a/android/filament-android/src/main/cpp/Texture.cpp b/android/filament-android/src/main/cpp/Texture.cpp
index ef778056c0ea..ff3fd36d2694 100644
--- a/android/filament-android/src/main/cpp/Texture.cpp
+++ b/android/filament-android/src/main/cpp/Texture.cpp
@@ -138,6 +138,13 @@ Java_com_google_android_filament_Texture_nBuilderImportTexture(JNIEnv*, jclass,
     builder->import((intptr_t)id);
 }
 
+extern "C"
+JNIEXPORT void JNICALL
+Java_com_google_android_filament_Texture_nBuilderExternal(JNIEnv*, jclass, jlong nativeBuilder) {
+    Texture::Builder *builder = (Texture::Builder *) nativeBuilder;
+    builder->external();
+}
+
 extern "C" JNIEXPORT jlong JNICALL
 Java_com_google_android_filament_Texture_nBuilderBuild(JNIEnv*, jclass,
         jlong nativeBuilder, jlong nativeEngine) {
diff --git a/android/filament-android/src/main/java/com/google/android/filament/Texture.java b/android/filament-android/src/main/java/com/google/android/filament/Texture.java
index 1cb732af13f2..eaf81adc3cfd 100644
--- a/android/filament-android/src/main/java/com/google/android/filament/Texture.java
+++ b/android/filament-android/src/main/java/com/google/android/filament/Texture.java
@@ -800,6 +800,19 @@ public Builder importTexture(long id) {
             return this;
         }
 
+        /**
+         * Creates an external texture. The content must be set using setExternalImage().
+         * The sampler can be SAMPLER_EXTERNAL or SAMPLER_2D depending on the format. Generally
+         * YUV formats must use SAMPLER_EXTERNAL. This depends on the backend features and is not
+         * validated.
+         * @return This Builder, for chaining calls.
+         */
+        @NonNull
+        public Builder external() {
+            nBuilderExternal(mNativeBuilder);
+            return this;
+        }
+
         /**
          * Creates a new <code>Texture</code> instance.
          * @param engine The {@link Engine} to associate this <code>Texture</code> with.
@@ -1261,6 +1274,7 @@ void clearNativeObject() {
     private static native void nBuilderUsage(long nativeBuilder, int flags);
     private static native void nBuilderSwizzle(long nativeBuilder, int r, int g, int b, int a);
     private static native void nBuilderImportTexture(long nativeBuilder, long id);
+    private static native void nBuilderExternal(long nativeBuilder);
     private static native long nBuilderBuild(long nativeBuilder, long nativeEngine);
 
     private static native int nGetWidth(long nativeTexture, int level);
diff --git a/android/gradle.properties b/android/gradle.properties
index 7082c1eab1a1..e4f778ef79e0 100644
--- a/android/gradle.properties
+++ b/android/gradle.properties
@@ -1,5 +1,5 @@
 GROUP=com.google.android.filament
-VERSION_NAME=1.56.5
+VERSION_NAME=1.56.6
 
 POM_DESCRIPTION=Real-time physically based rendering engine for Android.
 
diff --git a/build.sh b/build.sh
index 8c5d94a96db4..3f972d75c16e 100755
--- a/build.sh
+++ b/build.sh
@@ -23,6 +23,8 @@ function print_help {
     echo "        This is sometimes needed instead of -c (which still misses some clean steps)."
     echo "    -d"
     echo "        Enable matdbg."
+    echo "    -t"
+    echo "        Enable fgviewer."
     echo "    -f"
     echo "        Always invoke CMake before incremental builds."
     echo "    -g"
@@ -125,6 +127,27 @@ function print_matdbg_help {
     echo ""
 }
 
+function print_fgviewer_help {
+    echo "fgviewer is enabled in the build, but some extra steps are needed."
+    echo ""
+    echo "FOR DESKTOP BUILDS:"
+    echo ""
+    echo "Please set the port environment variable before launching. e.g., on macOS do:"
+    echo "   export FILAMENT_FGVIEWER_PORT=8085"
+    echo ""
+    echo "FOR ANDROID BUILDS:"
+    echo ""
+    echo "1) For Android Studio builds, make sure to set:"
+    echo "       -Pcom.google.android.filament.fgviewer"
+    echo "   option in Preferences > Build > Compiler > Command line options."
+    echo ""
+    echo "2) The port number is hardcoded to 8085 so you will need to do:"
+    echo "       adb forward tcp:8085 tcp:8085"
+    echo ""
+    echo "3) Be sure to enable INTERNET permission in your app's manifest file."
+    echo ""
+}
+
 # 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/android/ndk.version | cut -f 1 -d ".")}
 
@@ -172,6 +195,7 @@ VULKAN_ANDROID_GRADLE_OPTION=""
 EGL_ON_LINUX_OPTION="-DFILAMENT_SUPPORTS_EGL_ON_LINUX=OFF"
 
 MATDBG_OPTION="-DFILAMENT_ENABLE_MATDBG=OFF"
+FGVIEWER_OPTION="-DFILAMENT_ENABLE_FGVIEWER=OFF"
 MATDBG_GRADLE_OPTION=""
 
 MATOPT_OPTION=""
@@ -240,6 +264,7 @@ function build_desktop_target {
             -DCMAKE_BUILD_TYPE="$1" \
             -DCMAKE_INSTALL_PREFIX="../${lc_target}/filament" \
             ${EGL_ON_LINUX_OPTION} \
+            ${FGVIEWER_OPTION} \
             ${MATDBG_OPTION} \
             ${MATOPT_OPTION} \
             ${ASAN_UBSAN_OPTION} \
@@ -376,6 +401,7 @@ function build_android_target {
             -DFILAMENT_NDK_VERSION="${FILAMENT_NDK_VERSION}" \
             -DCMAKE_INSTALL_PREFIX="../android-${lc_target}/filament" \
             -DCMAKE_TOOLCHAIN_FILE="../../build/toolchain-${arch}-linux-android.cmake" \
+            ${FGVIEWER_OPTION} \
             ${MATDBG_OPTION} \
             ${MATOPT_OPTION} \
             ${VULKAN_ANDROID_OPTION} \
@@ -613,6 +639,7 @@ function build_ios_target {
             -DPLATFORM_NAME="${platform}" \
             -DIOS=1 \
             -DCMAKE_TOOLCHAIN_FILE=../../third_party/clang/iOS.cmake \
+            ${FGVIEWER_OPTION} \
             ${MATDBG_OPTION} \
             ${MATOPT_OPTION} \
             ${STEREOSCOPIC_OPTION} \
@@ -802,7 +829,7 @@ function check_debug_release_build {
 
 pushd "$(dirname "$0")" > /dev/null
 
-while getopts ":hacCfgijmp:q:uvslwedk:bx:S:X:" opt; do
+while getopts ":hacCfgijmp:q:uvslwedtk:bx:S:X:" opt; do
     case ${opt} in
         h)
             print_help
@@ -823,6 +850,12 @@ while getopts ":hacCfgijmp:q:uvslwedk:bx:S:X:" opt; do
             MATDBG_OPTION="-DFILAMENT_ENABLE_MATDBG=ON, -DFILAMENT_BUILD_FILAMAT=ON"
             MATDBG_GRADLE_OPTION="-Pcom.google.android.filament.matdbg"
             ;;
+        t)
+            # TODO: Uncomment below when fgviewer is ready
+            # PRINT_FGVIEWER_HELP=true
+            # FGVIEWER_OPTION="-DFILAMENT_ENABLE_FGVIEWER=ON"
+            #FGVIEWER_GRADLE_OPTION="-Pcom.google.android.filament.fgviewer"
+            ;;
         f)
             ISSUE_CMAKE_ALWAYS=true
             ;;
@@ -1027,3 +1060,7 @@ fi
 if [[ "${PRINT_MATDBG_HELP}" == "true" ]]; then
     print_matdbg_help
 fi
+
+if [[ "${PRINT_FGVIEWER_HELP}" == "true" ]]; then
+    print_fgviewer_help
+fi
diff --git a/filament/CMakeLists.txt b/filament/CMakeLists.txt
index 82e336215dd3..d218a3917048 100644
--- a/filament/CMakeLists.txt
+++ b/filament/CMakeLists.txt
@@ -561,6 +561,13 @@ target_link_libraries(${TARGET} PUBLIC filaflat)
 target_link_libraries(${TARGET} PUBLIC filabridge)
 target_link_libraries(${TARGET} PUBLIC ibl-lite)
 
+if (FILAMENT_ENABLE_FGVIEWER)
+    target_link_libraries(${TARGET} PUBLIC fgviewer)
+    add_definitions(-DFILAMENT_ENABLE_FGVIEWER=1)
+else()
+    add_definitions(-DFILAMENT_ENABLE_FGVIEWER=0)
+endif()
+
 if (FILAMENT_ENABLE_MATDBG)
     target_link_libraries(${TARGET} PUBLIC matdbg)
     add_definitions(-DFILAMENT_ENABLE_MATDBG=1)
diff --git a/filament/backend/include/private/backend/DriverAPI.inc b/filament/backend/include/private/backend/DriverAPI.inc
index 66556b0f41f3..6b951da975c5 100644
--- a/filament/backend/include/private/backend/DriverAPI.inc
+++ b/filament/backend/include/private/backend/DriverAPI.inc
@@ -214,6 +214,7 @@ DECL_DRIVER_API_R_N(backend::TextureHandle, createTextureViewSwizzle,
         backend::TextureSwizzle, a)
 
 DECL_DRIVER_API_R_N(backend::TextureHandle, createTextureExternalImage,
+        backend::SamplerType, target,
         backend::TextureFormat, format,
         uint32_t, width,
         uint32_t, height,
@@ -399,17 +400,6 @@ DECL_DRIVER_API_N(update3DImage,
 DECL_DRIVER_API_N(generateMipmaps,
         backend::TextureHandle, th)
 
-// Deprecated
-DECL_DRIVER_API_N(setExternalImage,
-        backend::TextureHandle, th,
-        void*, image)
-
-// Deprecated
-DECL_DRIVER_API_N(setExternalImagePlane,
-        backend::TextureHandle, th,
-        void*, image,
-        uint32_t, plane)
-
 DECL_DRIVER_API_N(setExternalStream,
         backend::TextureHandle, th,
         backend::StreamHandle, sh)
diff --git a/filament/backend/src/PlatformFactory.cpp b/filament/backend/src/PlatformFactory.cpp
index 86be6d231e02..cccd9439c3ec 100644
--- a/filament/backend/src/PlatformFactory.cpp
+++ b/filament/backend/src/PlatformFactory.cpp
@@ -24,7 +24,7 @@
     #if defined(FILAMENT_SUPPORTS_OPENGL) && !defined(FILAMENT_USE_EXTERNAL_GLES3)
         #include "backend/platforms/PlatformEGLAndroid.h"
     #endif
-#elif defined(IOS)
+#elif defined(FILAMENT_IOS)
     #if defined(FILAMENT_SUPPORTS_OPENGL) && !defined(FILAMENT_USE_EXTERNAL_GLES3)
         #include "backend/platforms/PlatformCocoaTouchGL.h"
     #endif
@@ -88,7 +88,7 @@ Platform* PlatformFactory::create(Backend* backend) noexcept {
         *backend = Backend::OPENGL;
 #elif defined(__ANDROID__)
         *backend = Backend::OPENGL;
-#elif defined(IOS) || defined(__APPLE__)
+#elif defined(FILAMENT_IOS) || defined(__APPLE__)
         *backend = Backend::METAL;
 #elif defined(FILAMENT_DRIVER_SUPPORTS_VULKAN)
         *backend = Backend::VULKAN;
@@ -119,7 +119,7 @@ Platform* PlatformFactory::create(Backend* backend) noexcept {
             return nullptr;
         #elif defined(__ANDROID__)
             return new PlatformEGLAndroid();
-        #elif defined(IOS)
+        #elif defined(FILAMENT_IOS)
             return new PlatformCocoaTouchGL();
         #elif defined(__APPLE__)
             return new PlatformCocoaGL();
diff --git a/filament/backend/src/metal/MetalBuffer.h b/filament/backend/src/metal/MetalBuffer.h
index f6fa90c1990b..ec724a9f0bdc 100644
--- a/filament/backend/src/metal/MetalBuffer.h
+++ b/filament/backend/src/metal/MetalBuffer.h
@@ -250,7 +250,7 @@ class MetalRingBuffer {
     // In practice, MetalRingBuffer is used for argument buffers, which are kept in the constant
     // address space. Constant buffers have specific alignment requirements when specifying an
     // offset.
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
 #if TARGET_OS_SIMULATOR
     // The iOS simulator has differing alignment requirements.
     static constexpr auto METAL_CONSTANT_BUFFER_OFFSET_ALIGNMENT = 256;
diff --git a/filament/backend/src/metal/MetalContext.h b/filament/backend/src/metal/MetalContext.h
index 158435150820..f85e08545bf7 100644
--- a/filament/backend/src/metal/MetalContext.h
+++ b/filament/backend/src/metal/MetalContext.h
@@ -155,6 +155,7 @@ struct MetalContext {
 
     RenderPassFlags currentRenderPassFlags;
     MetalRenderTarget* currentRenderTarget = nullptr;
+    bool validPipelineBound = false;
 
     // State trackers.
     PipelineStateTracker pipelineState;
diff --git a/filament/backend/src/metal/MetalDriver.mm b/filament/backend/src/metal/MetalDriver.mm
index d787c0cdb265..46dcb3716ea8 100644
--- a/filament/backend/src/metal/MetalDriver.mm
+++ b/filament/backend/src/metal/MetalDriver.mm
@@ -482,7 +482,9 @@
     mContext->textures.insert(construct_handle<MetalTexture>(th, *mContext, src, r, g, b, a));
 }
 
-void MetalDriver::createTextureExternalImageR(Handle<HwTexture> th, backend::TextureFormat format,
+void MetalDriver::createTextureExternalImageR(Handle<HwTexture> th,
+        backend::SamplerType target,
+        backend::TextureFormat format,
         uint32_t width, uint32_t height, backend::TextureUsage usage, void* image) {
     mContext->textures.insert(construct_handle<MetalTexture>(
             th, *mContext, format, width, height, usage, (CVPixelBufferRef)image));
@@ -907,7 +909,7 @@
 }
 
 ShaderModel MetalDriver::getShaderModel() const noexcept {
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
     return ShaderModel::MOBILE;
 #else
     return ShaderModel::DESKTOP;
@@ -981,7 +983,7 @@
         case MTLPixelFormatRGBA16Float:
             return true;
 
-#if !defined(IOS)
+#if !defined(FILAMENT_IOS)
         // Mipmappable only on desktop:
         case MTLPixelFormatR32Float:
         case MTLPixelFormatRG32Float:
@@ -989,7 +991,7 @@
             return true;
 #endif
 
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
         // Mipmappable only on iOS:
         case MTLPixelFormatRGB9E5Float:
             return true;
@@ -1191,10 +1193,6 @@
     CVPixelBufferRetain(pixelBuffer);
 }
 
-void MetalDriver::setExternalImage(Handle<HwTexture> th, void* image) {}
-
-void MetalDriver::setExternalImagePlane(Handle<HwTexture> th, void* image, uint32_t plane) {}
-
 void MetalDriver::setExternalStream(Handle<HwTexture> th, Handle<HwStream> sh) {
 }
 
@@ -1366,7 +1364,7 @@
     if (@available(iOS 13, *)) {
         MTLCaptureDescriptor* descriptor = [MTLCaptureDescriptor new];
         descriptor.captureObject = mContext->device;
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
         descriptor.destination = MTLCaptureDestinationDeveloperTools;
 #else
         descriptor.destination = MTLCaptureDestinationGPUTraceDocument;
@@ -1430,7 +1428,7 @@
                                                                width:srcTextureSize.width
                                                               height:srcTextureSize.height
                                                            mipmapped:NO];
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
     textureDescriptor.storageMode = MTLStorageModeShared;
 #else
     textureDescriptor.storageMode = MTLStorageModeManaged;
@@ -1449,7 +1447,7 @@
 
     mContext->blitter->blit(getPendingCommandBuffer(mContext), args, "readPixels blit");
 
-#if !defined(IOS)
+#if !defined(FILAMENT_IOS)
     // Managed textures on macOS require explicit synchronization between GPU / CPU.
     id <MTLBlitCommandEncoder> blitEncoder = [getPendingCommandBuffer(mContext) blitCommandEncoder];
     [blitEncoder synchronizeResource:readPixelsTexture];
@@ -1657,6 +1655,7 @@
     // during the draw call when the program is invalid. The shader compile error has already been
     // dumped to the console at this point, so it's fine to simply return early.
     if (FILAMENT_ENABLE_MATDBG && UTILS_UNLIKELY(!functions)) {
+        mContext->validPipelineBound = false;
         return;
     }
 
@@ -1789,6 +1788,8 @@
                                                    clamp:0.0];
         mContext->currentPolygonOffset = ps.polygonOffset;
     }
+
+    mContext->validPipelineBound = true;
 }
 
 void MetalDriver::bindRenderPrimitive(Handle<HwRenderPrimitive> rph) {
@@ -1886,6 +1887,10 @@
             << "draw() without a valid command encoder.";
     DEBUG_LOG("draw2(...)\n");
 
+    if (FILAMENT_ENABLE_MATDBG && UTILS_UNLIKELY(!mContext->validPipelineBound)) {
+        return;
+    }
+
     // Bind the offset data.
     if (mContext->dynamicOffsets.isDirty()) {
         const auto [size, data] = mContext->dynamicOffsets.getOffsets();
diff --git a/filament/backend/src/metal/MetalEnums.h b/filament/backend/src/metal/MetalEnums.h
index 10899baf95fc..5a2038ed1037 100644
--- a/filament/backend/src/metal/MetalEnums.h
+++ b/filament/backend/src/metal/MetalEnums.h
@@ -196,7 +196,7 @@ inline MTLPixelFormat getMetalFormatLinear(MTLPixelFormat format) {
         case MTLPixelFormatRG8Unorm_sRGB: return MTLPixelFormatRG8Unorm;
         case MTLPixelFormatRGBA8Unorm_sRGB: return MTLPixelFormatRGBA8Unorm;
         case MTLPixelFormatBGRA8Unorm_sRGB: return MTLPixelFormatBGRA8Unorm;
-#if !defined(IOS)
+#if !defined(FILAMENT_IOS)
         case MTLPixelFormatBC1_RGBA_sRGB: return MTLPixelFormatBC1_RGBA;
         case MTLPixelFormatBC2_RGBA_sRGB: return MTLPixelFormatBC2_RGBA;
         case MTLPixelFormatBC3_RGBA_sRGB: return MTLPixelFormatBC3_RGBA;
@@ -268,7 +268,7 @@ constexpr inline bool isMetalFormatStencil(MTLPixelFormat format) {
         case MTLPixelFormatStencil8:
         case MTLPixelFormatDepth32Float_Stencil8:
         case MTLPixelFormatX32_Stencil8:
-#if !defined(IOS)
+#if !defined(FILAMENT_IOS)
         case MTLPixelFormatDepth24Unorm_Stencil8:
         case MTLPixelFormatX24_Stencil8:
 #endif
diff --git a/filament/backend/src/metal/MetalHandles.mm b/filament/backend/src/metal/MetalHandles.mm
index 60cf484c86ea..fc12fe0a9a6f 100644
--- a/filament/backend/src/metal/MetalHandles.mm
+++ b/filament/backend/src/metal/MetalHandles.mm
@@ -157,7 +157,7 @@ static inline MTLTextureUsage getMetalTextureUsage(TextureUsage usage) {
         textureDescriptor.height = headlessHeight;
         // Specify MTLTextureUsageShaderRead so the headless surface can be blitted from.
         textureDescriptor.usage = MTLTextureUsageRenderTarget | MTLTextureUsageShaderRead;
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
         textureDescriptor.storageMode = MTLStorageModeShared;
 #else
         textureDescriptor.storageMode = MTLStorageModeManaged;
@@ -520,7 +520,7 @@ static void func(void* user) {
     const BOOL mipmapped = levels > 1;
     const BOOL multisampled = samples > 1;
 
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
     const BOOL textureArray = target == SamplerType::SAMPLER_2D_ARRAY;
     FILAMENT_CHECK_PRECONDITION(!textureArray || !multisampled)
             << "iOS does not support multisampled texture arrays.";
@@ -533,7 +533,7 @@ static void func(void* user) {
         switch (target) {
             case SamplerType::SAMPLER_2D:
                 return MTLTextureType2DMultisample;
-#if !defined(IOS)
+#if !defined(FILAMENT_IOS)
             case SamplerType::SAMPLER_2D_ARRAY:
                 return MTLTextureType2DMultisampleArray;
 #endif
@@ -856,7 +856,7 @@ static void func(void* user) {
     descriptor.height = region.size.height;
     descriptor.depth = region.size.depth;
 
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
     descriptor.storageMode = MTLStorageModeShared;
 #else
     descriptor.storageMode = MTLStorageModeManaged;
diff --git a/filament/backend/src/metal/MetalPlatform.mm b/filament/backend/src/metal/MetalPlatform.mm
index 31ce2a8070a5..4979e602ba1f 100644
--- a/filament/backend/src/metal/MetalPlatform.mm
+++ b/filament/backend/src/metal/MetalPlatform.mm
@@ -37,7 +37,7 @@
 id<MTLDevice> MetalPlatform::createDevice() noexcept {
     id<MTLDevice> result;
 
-#if !defined(IOS)
+#if !defined(FILAMENT_IOS)
     const bool forceIntegrated =
             NSProcessInfo.processInfo.environment[@"FILAMENT_FORCE_INTEGRATED_GPU"] != nil;
     if (forceIntegrated) {
diff --git a/filament/backend/src/metal/MetalState.mm b/filament/backend/src/metal/MetalState.mm
index 065e2b62cce3..c790e03c3048 100644
--- a/filament/backend/src/metal/MetalState.mm
+++ b/filament/backend/src/metal/MetalState.mm
@@ -150,7 +150,7 @@
                 MTLCompareFunctionNever : getCompareFunction(params.compareFunc);
     samplerDescriptor.supportArgumentBuffers = YES;
 
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
     // Older Apple devices (and the simulator) don't support setting a comparison function in
     // MTLSamplerDescriptor.
     // In practice, this means shadows are not supported when running in the simulator.
diff --git a/filament/backend/src/noop/NoopDriver.cpp b/filament/backend/src/noop/NoopDriver.cpp
index afc5ac808dfc..af3ad70fbb69 100644
--- a/filament/backend/src/noop/NoopDriver.cpp
+++ b/filament/backend/src/noop/NoopDriver.cpp
@@ -32,7 +32,7 @@ Dispatcher NoopDriver::getDispatcher() const noexcept {
 }
 
 ShaderModel NoopDriver::getShaderModel() const noexcept {
-#if defined(__ANDROID__) || defined(IOS) || defined(__EMSCRIPTEN__)
+#if defined(__ANDROID__) || defined(FILAMENT_IOS) || defined(__EMSCRIPTEN__)
     return ShaderModel::MOBILE;
 #else
     return ShaderModel::DESKTOP;
@@ -265,12 +265,6 @@ TimerQueryResult NoopDriver::getTimerQueryValue(Handle<HwTimerQuery> tqh, uint64
     return TimerQueryResult::ERROR;
 }
 
-void NoopDriver::setExternalImage(Handle<HwTexture> th, void* image) {
-}
-
-void NoopDriver::setExternalImagePlane(Handle<HwTexture> th, void* image, uint32_t plane) {
-}
-
 void NoopDriver::setExternalStream(Handle<HwTexture> th, Handle<HwStream> sh) {
 }
 
diff --git a/filament/backend/src/opengl/GLDescriptorSet.cpp b/filament/backend/src/opengl/GLDescriptorSet.cpp
index 1584f6aff774..79c65d9a125a 100644
--- a/filament/backend/src/opengl/GLDescriptorSet.cpp
+++ b/filament/backend/src/opengl/GLDescriptorSet.cpp
@@ -173,6 +173,7 @@ void GLDescriptorSet::update(OpenGLContext& gl,
 
             arg.target = t ? t->gl.target : 0;
             arg.id = t ? t->gl.id : 0;
+            arg.external = t ? t->gl.external :  false;
             if constexpr (std::is_same_v<T, Sampler> ||
                           std::is_same_v<T, SamplerWithAnisotropyWorkaround>) {
                 if constexpr (std::is_same_v<T, SamplerWithAnisotropyWorkaround>) {
@@ -285,7 +286,7 @@ void GLDescriptorSet::bind(
             } else if constexpr (std::is_same_v<T, Sampler>) {
                 GLuint const unit = p.getTextureUnit(set, binding);
                 if (arg.target) {
-                    gl.bindTexture(unit, arg.target, arg.id);
+                    gl.bindTexture(unit, arg.target, arg.id, arg.external);
                     gl.bindSampler(unit, arg.sampler);
                     if (UTILS_UNLIKELY(arg.ref)) {
                         updateTextureView(gl, handleAllocator, unit, arg);
@@ -296,7 +297,7 @@ void GLDescriptorSet::bind(
             } else if constexpr (std::is_same_v<T, SamplerWithAnisotropyWorkaround>) {
                 GLuint const unit = p.getTextureUnit(set, binding);
                 if (arg.target) {
-                    gl.bindTexture(unit, arg.target, arg.id);
+                    gl.bindTexture(unit, arg.target, arg.id, arg.external);
                     gl.bindSampler(unit, arg.sampler);
                     if (UTILS_UNLIKELY(arg.ref)) {
                         updateTextureView(gl, handleAllocator, unit, arg);
@@ -314,7 +315,7 @@ void GLDescriptorSet::bind(
                 // in ES2 the sampler parameters need to be set on the texture itself
                 GLuint const unit = p.getTextureUnit(set, binding);
                 if (arg.target) {
-                    gl.bindTexture(unit, arg.target, arg.id);
+                    gl.bindTexture(unit, arg.target, arg.id, arg.external);
                     SamplerParams const params = arg.params;
                     glTexParameteri(arg.target, GL_TEXTURE_MIN_FILTER,
                             (GLint)GLUtils::getTextureFilter(params.filterMin));
diff --git a/filament/backend/src/opengl/GLDescriptorSet.h b/filament/backend/src/opengl/GLDescriptorSet.h
index 51ac2afd884e..59b6b6ace57a 100644
--- a/filament/backend/src/opengl/GLDescriptorSet.h
+++ b/filament/backend/src/opengl/GLDescriptorSet.h
@@ -111,7 +111,9 @@ struct GLDescriptorSet : public HwDescriptorSet {
 
     // A sampler descriptor
     struct Sampler {
-        GLenum target = 0;                      // 4
+        uint16_t target;                        // 2 (GLenum)
+        bool external = false;                  // 1
+        bool reserved = false;                  // 1
         GLuint id = 0;                          // 4
         GLuint sampler = 0;                     // 4
         Handle<GLTextureRef> ref;               // 4
@@ -126,7 +128,9 @@ struct GLDescriptorSet : public HwDescriptorSet {
     };
 
     struct SamplerWithAnisotropyWorkaround {
-        GLenum target = 0;                      // 4
+        uint16_t target;                        // 2 (GLenum)
+        bool external = false;                  // 1
+        bool reserved = false;                  // 1
         GLuint id = 0;                          // 4
         GLuint sampler = 0;                     // 4
         Handle<GLTextureRef> ref;               // 4
@@ -143,7 +147,9 @@ struct GLDescriptorSet : public HwDescriptorSet {
 
     // A sampler descriptor for ES2
     struct SamplerGLES2 {
-        GLenum target = 0;                      // 4
+        uint16_t target;                        // 2 (GLenum)
+        bool external = false;                  // 1
+        bool reserved = false;                  // 1
         GLuint id = 0;                          // 4
         SamplerParams params{};                 // 4
         float anisotropy = 1.0f;                // 4
diff --git a/filament/backend/src/opengl/GLTexture.h b/filament/backend/src/opengl/GLTexture.h
index 5d721d3c2148..26784d156448 100644
--- a/filament/backend/src/opengl/GLTexture.h
+++ b/filament/backend/src/opengl/GLTexture.h
@@ -35,7 +35,7 @@ struct GLTextureRef {
     GLTextureRef() = default;
     // view reference counter
     uint16_t count = 1;
-    // current per-view values of the texture (in GL we can only have a single View active at
+    // Current per-view values of the texture (in GL we can only have a single View active at
     // a time, and this tracks that state). It's used to avoid unnecessarily change state.
     int8_t baseLevel = 127;
     int8_t maxLevel = -1;
@@ -50,7 +50,7 @@ struct GLTextureRef {
 struct GLTexture : public HwTexture {
     using HwTexture::HwTexture;
     struct GL {
-        GL() noexcept : imported(false), sidecarSamples(1), reserved1(0) {}
+        GL() noexcept : imported(false), external(false), sidecarSamples(1), reserved1(0) {}
         GLuint id = 0;          // texture or renderbuffer id
         GLenum target = 0;
         GLenum internalFormat = 0;
@@ -62,7 +62,8 @@ struct GLTexture : public HwTexture {
         int8_t maxLevel = -1;
         uint8_t reserved0 = 0;
         bool imported           : 1;
-        uint8_t sidecarSamples  : 4;
+        bool external           : 1;
+        uint8_t sidecarSamples  : 3;
         uint8_t reserved1       : 3;
         std::array<TextureSwizzle, 4> swizzle{
                 TextureSwizzle::CHANNEL_0,
diff --git a/filament/backend/src/opengl/OpenGLContext.cpp b/filament/backend/src/opengl/OpenGLContext.cpp
index d664e9e89ac2..f652d9265962 100644
--- a/filament/backend/src/opengl/OpenGLContext.cpp
+++ b/filament/backend/src/opengl/OpenGLContext.cpp
@@ -408,7 +408,7 @@ void OpenGLContext::initProcs(Procs* procs,
     procs->maxShaderCompilerThreadsKHR = +[](GLuint) {};
 
 #ifdef BACKEND_OPENGL_VERSION_GLES
-#   ifndef IOS // IOS is guaranteed to have ES3.x
+#   ifndef FILAMENT_IOS // FILAMENT_IOS is guaranteed to have ES3.x
 #       ifndef __EMSCRIPTEN__
     if (UTILS_UNLIKELY(major == 2)) {
         // Runtime OpenGL version is ES 2.x
@@ -438,7 +438,7 @@ void OpenGLContext::initProcs(Procs* procs,
         procs->maxShaderCompilerThreadsKHR = glMaxShaderCompilerThreadsKHR;
     }
 #       endif // __EMSCRIPTEN__
-#   endif // IOS
+#   endif // FILAMENT_IOS
 #else
     procs->maxShaderCompilerThreadsKHR = glMaxShaderCompilerThreadsARB;
 #endif
@@ -576,14 +576,14 @@ void OpenGLContext::initBugs(Bugs* bugs, Extensions const& exts,
     }
 
 #ifdef BACKEND_OPENGL_VERSION_GLES
-#   ifndef IOS // IOS is guaranteed to have ES3.x
+#   ifndef FILAMENT_IOS // FILAMENT_IOS is guaranteed to have ES3.x
     if (UTILS_UNLIKELY(major == 2)) {
         if (UTILS_UNLIKELY(!exts.OES_vertex_array_object)) {
             // we activate this workaround path, which does the reset of array buffer
             bugs->vao_doesnt_store_element_array_buffer_binding = true;
         }
     }
-#   endif // IOS
+#   endif // FILAMENT_IOS
 #else
     // feedback loops are allowed on GL desktop as long as writes are disabled
     bugs->allow_read_only_ancillary_feedback_loop = true;
@@ -622,7 +622,7 @@ FeatureLevel OpenGLContext::resolveFeatureLevel(GLint major, GLint minor,
             }
         }
     }
-#   ifndef IOS // IOS is guaranteed to have ES3.x
+#   ifndef FILAMENT_IOS // FILAMENT_IOS is guaranteed to have ES3.x
     else if (UTILS_UNLIKELY(major == 2)) {
         // Runtime OpenGL version is ES 2.x
         // note: mandatory extensions (all supported by Mali-400 and Adreno 304)
@@ -634,7 +634,7 @@ FeatureLevel OpenGLContext::resolveFeatureLevel(GLint major, GLint minor,
         //      OES_texture_npot
         featureLevel = FeatureLevel::FEATURE_LEVEL_0;
     }
-#   endif // IOS
+#   endif // FILAMENT_IOS
 #else
     assert_invariant(gets.max_texture_image_units >= 16);
     assert_invariant(gets.max_combined_texture_image_units >= 32);
diff --git a/filament/backend/src/opengl/OpenGLContext.h b/filament/backend/src/opengl/OpenGLContext.h
index 39ceb346787e..72e3f8f2b124 100644
--- a/filament/backend/src/opengl/OpenGLContext.h
+++ b/filament/backend/src/opengl/OpenGLContext.h
@@ -131,7 +131,7 @@ class OpenGLContext final : public TimerQueryFactoryInterface {
     }
 
     inline bool isES2() const noexcept {
-#if defined(BACKEND_OPENGL_VERSION_GLES) && !defined(IOS)
+#if defined(BACKEND_OPENGL_VERSION_GLES) && !defined(FILAMENT_IOS)
 #   ifndef BACKEND_OPENGL_LEVEL_GLES30
             return true;
 #   else
@@ -153,7 +153,7 @@ class OpenGLContext final : public TimerQueryFactoryInterface {
 
           void pixelStore(GLenum, GLint) noexcept;
     inline void activeTexture(GLuint unit) noexcept;
-    inline void bindTexture(GLuint unit, GLuint target, GLuint texId) noexcept;
+    inline void bindTexture(GLuint unit, GLuint target, GLuint texId, bool external) noexcept;
 
            void unbindTexture(GLenum target, GLuint id) noexcept;
            void unbindTextureUnit(GLuint unit) noexcept;
@@ -761,7 +761,9 @@ void OpenGLContext::bindBufferRange(GLenum target, GLuint index, GLuint buffer,
 #endif
 }
 
-void OpenGLContext::bindTexture(GLuint unit, GLuint target, GLuint texId) noexcept {
+void OpenGLContext::bindTexture(GLuint unit, GLuint target, GLuint texId, bool external) noexcept {
+    //  another texture is bound to the same unit with a different target,
+    //  unbind the texture from the current target
     update_state(state.textures.units[unit].target, target, [&]() {
         activeTexture(unit);
         glBindTexture(state.textures.units[unit].target, 0);
@@ -769,7 +771,7 @@ void OpenGLContext::bindTexture(GLuint unit, GLuint target, GLuint texId) noexce
     update_state(state.textures.units[unit].id, texId, [&]() {
         activeTexture(unit);
         glBindTexture(target, texId);
-    }, target == GL_TEXTURE_EXTERNAL_OES);
+    }, external);
 }
 
 void OpenGLContext::useProgram(GLuint program) noexcept {
diff --git a/filament/backend/src/opengl/OpenGLDriver.cpp b/filament/backend/src/opengl/OpenGLDriver.cpp
index 79580fc7c46e..736fa0d6769b 100644
--- a/filament/backend/src/opengl/OpenGLDriver.cpp
+++ b/filament/backend/src/opengl/OpenGLDriver.cpp
@@ -402,7 +402,7 @@ void OpenGLDriver::setPushConstant(backend::ShaderStage stage, uint8_t index,
 
 void OpenGLDriver::bindTexture(GLuint unit, GLTexture const* t) noexcept {
     assert_invariant(t != nullptr);
-    mContext.bindTexture(unit, t->gl.target, t->gl.id);
+    mContext.bindTexture(unit, t->gl.target, t->gl.id, t->gl.external);
 }
 
 bool OpenGLDriver::useProgram(OpenGLProgram* p) noexcept {
@@ -1052,17 +1052,49 @@ void OpenGLDriver::createTextureViewSwizzleR(Handle<HwTexture> th, Handle<HwText
     CHECK_GL_ERROR(utils::slog.e)
 }
 
-void OpenGLDriver::createTextureExternalImageR(Handle<HwTexture> th, backend::TextureFormat format,
-        uint32_t width, uint32_t height, backend::TextureUsage usage, void* image) {
-    createTextureR(th, SamplerType::SAMPLER_EXTERNAL, 1, format, 1, width, height, 1, usage);
-    setExternalImage(th, image);
+void OpenGLDriver::createTextureExternalImageR(Handle<HwTexture> th, SamplerType target,
+    TextureFormat format, uint32_t width, uint32_t height, TextureUsage usage, void* image) {
+    DEBUG_MARKER()
+
+    usage |= TextureUsage::SAMPLEABLE;
+    usage &= ~TextureUsage::UPLOADABLE;
+
+    auto& gl = mContext;
+    GLenum internalFormat = getInternalFormat(format);
+    if (UTILS_UNLIKELY(gl.isES2())) {
+        // on ES2, format and internal format must match
+        // FIXME: handle compressed texture format
+        internalFormat = textureFormatToFormatAndType(format).first;
+    }
+    assert_invariant(internalFormat);
+
+    GLTexture* const t = construct<GLTexture>(th, target, 1, 1, width, height, 1, format, usage);
+    assert_invariant(t);
+
+    t->externalTexture = mPlatform.createExternalImageTexture();
+    if (t->externalTexture) {
+        t->gl.target = t->externalTexture->target;
+        t->gl.id = t->externalTexture->id;
+        // internalFormat actually depends on the external image, but it doesn't matter
+        // because it's not used anywhere for anything important.
+        t->gl.internalFormat = internalFormat;
+        t->gl.baseLevel = 0;
+        t->gl.maxLevel = 0;
+        t->gl.external = true; // forces bindTexture() call (they're never cached)
+    }
+
+    bindTexture(OpenGLContext::DUMMY_TEXTURE_BINDING, t);
+    if (mPlatform.setExternalImage(image, t->externalTexture)) {
+        // the target and id can be reset each time
+        t->gl.target = t->externalTexture->target;
+        t->gl.id = t->externalTexture->id;
+    }
 }
 
 void OpenGLDriver::createTextureExternalImagePlaneR(Handle<HwTexture> th,
         backend::TextureFormat format, uint32_t width, uint32_t height, backend::TextureUsage usage,
         void* image, uint32_t plane) {
-    createTextureR(th, SamplerType::SAMPLER_EXTERNAL, 1, format, 1, width, height, 1, usage);
-    setExternalImagePlane(th, image, plane);
+    // not relevant for the OpenGL backend
 }
 
 void OpenGLDriver::importTextureR(Handle<HwTexture> th, intptr_t id,
@@ -1082,6 +1114,7 @@ void OpenGLDriver::importTextureR(Handle<HwTexture> th, intptr_t id,
     switch (target) {
         case SamplerType::SAMPLER_EXTERNAL:
             t->gl.target = GL_TEXTURE_EXTERNAL_OES;
+            t->gl.external = true; // forces bindTexture() call (they're never cached)
             break;
         case SamplerType::SAMPLER_2D:
             t->gl.target = GL_TEXTURE_2D;
@@ -1348,13 +1381,13 @@ void OpenGLDriver::framebufferTexture(TargetBufferInfo const& binfo,
 #ifndef FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2
 
                 // TODO: support multiview for iOS and WebGL
-#if !defined(__EMSCRIPTEN__) && !defined(IOS)
+#if !defined(__EMSCRIPTEN__) && !defined(FILAMENT_IOS)
                 if (layerCount > 1) {
                     // if layerCount > 1, it means we use the multiview extension.
                     glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, attachment,
                         t->gl.id, 0, binfo.layer, layerCount);
                 } else
-#endif // !defined(__EMSCRIPTEN__) && !defined(IOS)
+#endif // !defined(__EMSCRIPTEN__) && !defined(FILAMENT_IOS)
                 {
                     // GL_TEXTURE_2D_MULTISAMPLE_ARRAY is not supported in GLES
                     glFramebufferTextureLayer(GL_FRAMEBUFFER, attachment,
@@ -2774,25 +2807,6 @@ void OpenGLDriver::setupExternalImage(void* image) {
     mPlatform.retainExternalImage(image);
 }
 
-void OpenGLDriver::setExternalImage(Handle<HwTexture> th, void* image) {
-    DEBUG_MARKER()
-    GLTexture* t = handle_cast<GLTexture*>(th);
-    assert_invariant(t);
-    assert_invariant(t->target == SamplerType::SAMPLER_EXTERNAL);
-
-    bindTexture(OpenGLContext::DUMMY_TEXTURE_BINDING, t);
-    if (mPlatform.setExternalImage(image, t->externalTexture)) {
-        // the target and id can be reset each time
-        t->gl.target = t->externalTexture->target;
-        t->gl.id = t->externalTexture->id;
-        bindTexture(OpenGLContext::DUMMY_TEXTURE_BINDING, t);
-    }
-}
-
-void OpenGLDriver::setExternalImagePlane(Handle<HwTexture> th, void* image, uint32_t plane) {
-    DEBUG_MARKER()
-}
-
 void OpenGLDriver::setExternalStream(Handle<HwTexture> th, Handle<HwStream> sh) {
     auto& gl = mContext;
     if (gl.ext.OES_EGL_image_external_essl3) {
@@ -3512,7 +3526,7 @@ void OpenGLDriver::endFrame(UTILS_UNUSED uint32_t frameId) {
     auto& gl = mContext;
     gl.bindVertexArray(nullptr);
     for (int unit = OpenGLContext::DUMMY_TEXTURE_BINDING; unit >= 0; unit--) {
-        gl.bindTexture(unit, GL_TEXTURE_2D, 0);
+        gl.bindTexture(unit, GL_TEXTURE_2D, 0, false);
     }
     gl.disable(GL_CULL_FACE);
     gl.depthFunc(GL_LESS);
diff --git a/filament/backend/src/opengl/gl_headers.h b/filament/backend/src/opengl/gl_headers.h
index 04ad63ff6acc..636bdb48241b 100644
--- a/filament/backend/src/opengl/gl_headers.h
+++ b/filament/backend/src/opengl/gl_headers.h
@@ -56,7 +56,7 @@
     #   define FILAMENT_SILENCE_NOT_SUPPORTED_BY_ES2
     #endif
 
-#elif defined(IOS)
+#elif defined(FILAMENT_IOS)
 
     #define GLES_SILENCE_DEPRECATION
 
@@ -81,7 +81,7 @@
 #if defined(GL_VERSION_4_5)
 #elif defined(GL_ES_VERSION_3_1)
 #elif defined(GL_ES_VERSION_3_0)
-#   if !defined(IOS) && !defined(__EMSCRIPTEN__)
+#   if !defined(FILAMENT_IOS) && !defined(__EMSCRIPTEN__)
 #       error "GLES 3.0 headers only supported on iOS and WebGL2"
 #   endif
 #elif defined(GL_ES_VERSION_2_0)
@@ -98,7 +98,7 @@
 
 #if defined(GL_ES_VERSION_2_0)  // this basically means all versions of GLES
 
-#if defined(IOS)
+#if defined(FILAMENT_IOS)
 
 // iOS headers only provide prototypes, nothing to do.
 
@@ -271,7 +271,7 @@ void glGetBufferSubData(GLenum target, GLintptr offset, GLsizeiptr size, void *d
 #endif
 
 #ifdef GL_ES_VERSION_2_0
-#   ifndef IOS
+#   ifndef FILAMENT_IOS
 #      ifndef GL_OES_vertex_array_object
 #          error "Headers with GL_OES_vertex_array_object are mandatory unless on iOS"
 #      endif
diff --git a/filament/backend/src/opengl/platforms/PlatformEGL.cpp b/filament/backend/src/opengl/platforms/PlatformEGL.cpp
index 38b8b9d50493..9e6b628f02b9 100644
--- a/filament/backend/src/opengl/platforms/PlatformEGL.cpp
+++ b/filament/backend/src/opengl/platforms/PlatformEGL.cpp
@@ -715,14 +715,16 @@ void PlatformEGL::destroyExternalImage(ExternalTexture* texture) noexcept {
 
 bool PlatformEGL::setExternalImage(void* externalImage,
         UTILS_UNUSED_IN_RELEASE ExternalTexture* texture) noexcept {
-    if (UTILS_LIKELY(ext.gl.OES_EGL_image_external_essl3)) {
-        assert_invariant(texture->target == GL_TEXTURE_EXTERNAL_OES);
+
+    // OES_EGL_image_external_essl3 must be present if the target is TEXTURE_EXTERNAL_OES
+    // GL_OES_EGL_image must be present if TEXTURE_2D is used
+
+#if defined(GL_OES_EGL_image) || defined(GL_OES_EGL_image_external_essl3)
         // the texture is guaranteed to be bound here.
-#ifdef GL_OES_EGL_image
-        glEGLImageTargetTexture2DOES(GL_TEXTURE_EXTERNAL_OES,
+        glEGLImageTargetTexture2DOES(texture->target,
                 static_cast<GLeglImageOES>(externalImage));
 #endif
-    }
+
     return true;
 }
 
diff --git a/filament/backend/src/vulkan/VulkanDriver.cpp b/filament/backend/src/vulkan/VulkanDriver.cpp
index 25a2448b2918..520ea22b78ff 100644
--- a/filament/backend/src/vulkan/VulkanDriver.cpp
+++ b/filament/backend/src/vulkan/VulkanDriver.cpp
@@ -288,7 +288,7 @@ Driver* VulkanDriver::create(VulkanPlatform* platform, VulkanContext const& cont
 }
 
 ShaderModel VulkanDriver::getShaderModel() const noexcept {
-#if defined(__ANDROID__) || defined(IOS)
+#if defined(__ANDROID__) || defined(FILAMENT_IOS)
     return ShaderModel::MOBILE;
 #else
     return ShaderModel::DESKTOP;
@@ -543,7 +543,8 @@ void VulkanDriver::createTextureViewSwizzleR(Handle<HwTexture> th, Handle<HwText
    texture.inc();
 }
 
-void VulkanDriver::createTextureExternalImageR(Handle<HwTexture> th, backend::TextureFormat format,
+void VulkanDriver::createTextureExternalImageR(Handle<HwTexture> th,
+        backend::SamplerType target,  backend::TextureFormat format,
         uint32_t width, uint32_t height, backend::TextureUsage usage, void* externalImage) {
     FVK_SYSTRACE_SCOPE();
 
@@ -1189,13 +1190,6 @@ TimerQueryResult VulkanDriver::getTimerQueryValue(Handle<HwTimerQuery> tqh, uint
     return TimerQueryResult::AVAILABLE;
 }
 
-void VulkanDriver::setExternalImage(Handle<HwTexture> th, void* image) {
-
-}
-
-void VulkanDriver::setExternalImagePlane(Handle<HwTexture> th, void* image, uint32_t plane) {
-}
-
 void VulkanDriver::setExternalStream(Handle<HwTexture> th, Handle<HwStream> sh) {
 }
 
diff --git a/filament/backend/src/vulkan/platform/VulkanPlatformApple.mm b/filament/backend/src/vulkan/platform/VulkanPlatformApple.mm
index 6504ae3a7c47..6aa18749d335 100644
--- a/filament/backend/src/vulkan/platform/VulkanPlatformApple.mm
+++ b/filament/backend/src/vulkan/platform/VulkanPlatformApple.mm
@@ -32,7 +32,7 @@
     #ifndef VK_MVK_macos_surface
          #error VK_MVK_macos_surface is not defined
     #endif
-#elif defined(IOS)
+#elif defined(FILAMENT_IOS)
     // Metal is not available when building for the iOS simulator on Desktop.
     #define METAL_AVAILABLE __has_include(<QuartzCore/CAMetalLayer.h>)
     #if METAL_AVAILABLE
@@ -56,7 +56,7 @@
     ExtensionSet const ret = {
     #if defined(__APPLE__)
         VK_MVK_MACOS_SURFACE_EXTENSION_NAME,  // TODO: replace with VK_EXT_metal_surface
-    #elif defined(IOS) && defined(METAL_AVAILABLE)
+    #elif defined(FILAMENT_IOS) && defined(METAL_AVAILABLE)
         VK_MVK_IOS_SURFACE_EXTENSION_NAME,
     #endif
     };
@@ -90,7 +90,7 @@
         VkResult result = vkCreateMacOSSurfaceMVK((VkInstance) instance, &createInfo, VKALLOC,
                 (VkSurfaceKHR*) &surface);
         FILAMENT_CHECK_POSTCONDITION(result == VK_SUCCESS) << "vkCreateMacOSSurfaceMVK error.";
-    #elif defined(IOS) && defined(METAL_AVAILABLE)
+    #elif defined(FILAMENT_IOS) && defined(METAL_AVAILABLE)
         CAMetalLayer* metalLayer = (CAMetalLayer*) nativeWindow;
         // Create the VkSurface.
         FILAMENT_CHECK_POSTCONDITION(vkCreateIOSSurfaceMVK)
diff --git a/filament/backend/test/BackendTest.cpp b/filament/backend/test/BackendTest.cpp
index 6eede04f00c0..ff4e8bb1cabb 100644
--- a/filament/backend/test/BackendTest.cpp
+++ b/filament/backend/test/BackendTest.cpp
@@ -33,7 +33,7 @@ static constexpr size_t CONFIG_COMMAND_BUFFERS_SIZE     = 3 * CONFIG_MIN_COMMAND
 using namespace filament;
 using namespace filament::backend;
 
-#ifndef IOS
+#ifndef FILAMENT_IOS
 #include <imageio/ImageEncoder.h>
 #include <image/ColorTransform.h>
 
@@ -177,7 +177,7 @@ void BackendTest::readPixelsAndAssertHash(const char* testName, size_t width, si
 
                 // Export a screenshot, if requested.
                 if (c->exportScreenshot) {
-#ifndef IOS
+#ifndef FILAMENT_IOS
                     LinearImage image(c->width, c->height, 4);
                     image = toLinearWithAlpha<uint8_t>(c->width, c->height, c->width * 4,
                             (uint8_t*) buffer);
diff --git a/filament/backend/test/test_Blit.cpp b/filament/backend/test/test_Blit.cpp
index 8ba0be44c949..b664c864d28a 100644
--- a/filament/backend/test/test_Blit.cpp
+++ b/filament/backend/test/test_Blit.cpp
@@ -24,7 +24,7 @@
 
 #include <fstream>
 
-#ifndef IOS
+#ifndef FILAMENT_IOS
 #include <imageio/ImageEncoder.h>
 #include <image/ColorTransform.h>
 #endif
@@ -67,7 +67,7 @@ struct ScreenshotParams {
     uint32_t pixelHashResult;
 };
 
-#ifdef IOS
+#ifdef FILAMENT_IOS
 static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> rt, ScreenshotParams* params) {}
 #else
 static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> rt, ScreenshotParams* params) {
diff --git a/filament/backend/test/test_FeedbackLoops.cpp b/filament/backend/test/test_FeedbackLoops.cpp
index bb7a83416aee..df1aaf5471bb 100644
--- a/filament/backend/test/test_FeedbackLoops.cpp
+++ b/filament/backend/test/test_FeedbackLoops.cpp
@@ -31,7 +31,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#ifndef IOS
+#ifndef FILAMENT_IOS
 #include <imageio/ImageEncoder.h>
 #include <image/ColorTransform.h>
 
@@ -112,7 +112,7 @@ static void dumpScreenshot(DriverApi& dapi, Handle<HwRenderTarget> rt) {
         int w = kTexWidth, h = kTexHeight;
         const uint32_t* texels = (uint32_t*) buffer;
         sPixelHashResult = utils::hash::murmur3(texels, size / 4, 0);
-#ifndef IOS
+#ifndef FILAMENT_IOS
         LinearImage image(w, h, 4);
         image = toLinearWithAlpha<uint8_t>(w, h, w * 4, (uint8_t*) buffer);
         std::ofstream pngstrm("feedback.png", std::ios::binary | std::ios::trunc);
diff --git a/filament/backend/test/test_ReadPixels.cpp b/filament/backend/test/test_ReadPixels.cpp
index ee1a37cd9c28..873c34438818 100644
--- a/filament/backend/test/test_ReadPixels.cpp
+++ b/filament/backend/test/test_ReadPixels.cpp
@@ -28,7 +28,7 @@
 using namespace filament;
 using namespace filament::backend;
 
-#ifndef IOS
+#ifndef FILAMENT_IOS
 #include <imageio/ImageEncoder.h>
 #include <image/ColorTransform.h>
 
@@ -137,7 +137,7 @@ TEST_F(ReadPixelsTest, ReadPixels) {
         }
 
         void exportScreenshot(void* pixelData) const {
-            #ifndef IOS
+            #ifndef FILAMENT_IOS
             const size_t width = readRect.width, height = readRect.height;
             LinearImage image(width, height, 4);
             if (format == PixelDataFormat::RGBA && type == PixelDataType::UBYTE) {
diff --git a/filament/backend/test/test_RenderExternalImage.cpp b/filament/backend/test/test_RenderExternalImage.cpp
index 414e9c414d9b..643545a2bec4 100644
--- a/filament/backend/test/test_RenderExternalImage.cpp
+++ b/filament/backend/test/test_RenderExternalImage.cpp
@@ -227,7 +227,8 @@ TEST_F(BackendTest, RenderExternalImage) {
 
     api.setupExternalImage(pixBuffer);
     backend::Handle<HwTexture> texture =
-            api.createTextureExternalImage(TextureFormat::RGBA8, 1024, 1024, usage, pixBuffer);
+            api.createTextureExternalImage(SamplerType::SAMPLER_EXTERNAL,
+                    TextureFormat::RGBA8, 1024, 1024, usage, pixBuffer);
 
     // We're now free to release the buffer.
     CVBufferRelease(pixBuffer);
diff --git a/filament/include/filament/Options.h b/filament/include/filament/Options.h
index 3966053ed207..93bba80cd8eb 100644
--- a/filament/include/filament/Options.h
+++ b/filament/include/filament/Options.h
@@ -438,7 +438,7 @@ struct MultiSampleAntiAliasingOptions {
  * @see setTemporalAntiAliasingOptions()
  */
 struct TemporalAntiAliasingOptions {
-    float filterWidth = 1.0f;   //!< reconstruction filter width typically between 0.2 (sharper, aliased) and 1.5 (smoother)
+    float filterWidth = 1.0f;   //!< reconstruction filter width typically between 1 (sharper) and 2 (smoother)
     float feedback = 0.12f;     //!< history feedback, between 0 (maximum temporal AA) and 1 (no temporal AA).
     float lodBias = -1.0f;      //!< texturing lod bias (typically -1 or -2)
     float sharpness = 0.0f;     //!< post-TAA sharpen, especially useful when upscaling is true.
diff --git a/filament/include/filament/Texture.h b/filament/include/filament/Texture.h
index b351c4294351..6813b13e736f 100644
--- a/filament/include/filament/Texture.h
+++ b/filament/include/filament/Texture.h
@@ -261,6 +261,18 @@ class UTILS_PUBLIC Texture : public FilamentAPI {
          */
         Builder& import(intptr_t id) noexcept;
 
+        /**
+         * Creates an external texture. The content must be set using setExternalImage().
+         * The sampler can be SAMPLER_EXTERNAL or SAMPLER_2D depending on the format. Generally
+         * YUV formats must use SAMPLER_EXTERNAL. This depends on the backend features and is not
+         * validated.
+         *
+         * If the Sampler is set to SAMPLER_EXTERNAL, external() is implied.
+         *
+         * @return
+         */
+        Builder& external() noexcept;
+
     private:
         friend class FTexture;
     };
@@ -395,7 +407,7 @@ class UTILS_PUBLIC Texture : public FilamentAPI {
 
 
     /**
-     * Specify the external image to associate with this Texture. Typically the external
+     * Specify the external image to associate with this Texture. 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:
      *   - only the level of detail (lod) 0 can be specified
@@ -420,7 +432,7 @@ class UTILS_PUBLIC Texture : public FilamentAPI {
     void setExternalImage(Engine& engine, void* UTILS_NONNULL image) noexcept;
 
     /**
-     * Specify the external image and plane to associate with this Texture. Typically the external
+     * Specify the external image and plane to associate with this Texture. Typically, the external
      * image is OS specific, and can be a video or camera frame. When using this method, the
      * external image must be a planar type (such as a YUV camera frame). The plane parameter
      * selects which image plane is bound to this texture.
diff --git a/filament/src/PostProcessManager.cpp b/filament/src/PostProcessManager.cpp
index 90c743e58459..1a96335f2a72 100644
--- a/filament/src/PostProcessManager.cpp
+++ b/filament/src/PostProcessManager.cpp
@@ -2622,7 +2622,7 @@ void PostProcessManager::TaaJitterCamera(
     current.projection = inoutCameraInfo->projection * inoutCameraInfo->getUserViewMatrix();
     current.frameId = previous.frameId + 1;
 
-    auto jitterPosition = [pattern = taaOptions.jitterPattern](size_t frameIndex){
+    auto jitterPosition = [pattern = taaOptions.jitterPattern](size_t frameIndex) -> float2 {
         using JitterPattern = TemporalAntiAliasingOptions::JitterPattern;
         switch (pattern) {
             case JitterPattern::RGSS_X4:
@@ -2636,6 +2636,7 @@ void PostProcessManager::TaaJitterCamera(
             case JitterPattern::HALTON_23_X32:
                 return sHaltonSamples(frameIndex);
         }
+        return { 0.0f, 0.0f };
     };
 
     // sample position within a pixel [-0.5, 0.5]
@@ -2759,15 +2760,31 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::taa(FrameGraph& fg,
                 }};
 
                 constexpr float2 sampleOffsets[9] = {
-                        { -1.0f, -1.0f }, {  0.0f, -1.0f }, {  1.0f, -1.0f },
-                        { -1.0f,  0.0f }, {  0.0f,  0.0f }, {  1.0f,  0.0f },
-                        { -1.0f,  1.0f }, {  0.0f,  1.0f }, {  1.0f,  1.0f },
+                        { -1.0f, -1.0f }, {  0.0f, -1.0f }, {  1.0f, -1.0f }, { -1.0f,  0.0f },
+                        {  0.0f,  0.0f },
+                        {  1.0f,  0.0f }, { -1.0f,  1.0f }, {  0.0f,  1.0f }, {  1.0f,  1.0f },
                 };
 
                 constexpr float2 subSampleOffsets[4] = {
-                        { -0.25f, 0.25f }, {  0.25f, 0.25f }, { 0.25f, -0.25f }, { -0.25f, -0.25f }
+                        { -0.25f,  0.25f },
+                        {  0.25f,  0.25f },
+                        {  0.25f, -0.25f },
+                        { -0.25f, -0.25f }
                 };
 
+                UTILS_UNUSED
+                auto const lanczos = [](float x, float a) -> float {
+                    if (x <= std::numeric_limits<float>::epsilon()) {
+                        return 1.0f;
+                    }
+                    if (std::abs(x) <= a) {
+                        return (a * std::sin(f::PI * x) * std::sin(f::PI * x / a))
+                               / ((f::PI * f::PI) * (x * x));
+                    }
+                    return 0.0f;
+                };
+
+                float const filterWidth = std::clamp(taaOptions.filterWidth, 1.0f, 2.0f);
                 float4 sum = 0.0;
                 float4 weights[9];
 
@@ -2777,11 +2794,9 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::taa(FrameGraph& fg,
                 for (size_t i = 0; i < 9; i++) {
                     float2 const o = sampleOffsets[i];
                     for (size_t j = 0; j < 4; j++) {
-                        float2 const s = taaOptions.upscaling ? subSampleOffsets[j] : float2{ 0 };
-                        float2 const d = (o - current.jitter - s) / taaOptions.filterWidth;
-                        // This is a gaussian fit of a 3.3-wide Blackman-Harris window
-                        // see: "High Quality Temporal Supersampling" by Brian Karis
-                        weights[i][j] = std::exp(-2.29f * (d.x * d.x + d.y * d.y));
+                        float2 const subPixelOffset = taaOptions.upscaling ? subSampleOffsets[j] : float2{ 0 };
+                        float2 const d = (o - (current.jitter - subPixelOffset)) / filterWidth;
+                        weights[i][j] = lanczos(length(d), filterWidth);
                     }
                     sum += weights[i];
                 }
diff --git a/filament/src/PostProcessManager.h b/filament/src/PostProcessManager.h
index e7c9b142c770..7ed439589403 100644
--- a/filament/src/PostProcessManager.h
+++ b/filament/src/PostProcessManager.h
@@ -428,7 +428,7 @@ class PostProcessManager {
 
     template<size_t SIZE>
     struct JitterSequence {
-        auto operator()(size_t i) const noexcept { return positions[i % SIZE] - 0.5f; }
+        math::float2 operator()(size_t i) const noexcept { return positions[i % SIZE] - 0.5f; }
         const std::array<math::float2, SIZE> positions;
     };
 
diff --git a/filament/src/RenderPass.cpp b/filament/src/RenderPass.cpp
index 7a4de35a3cc1..5b9d94613eae 100644
--- a/filament/src/RenderPass.cpp
+++ b/filament/src/RenderPass.cpp
@@ -680,8 +680,6 @@ RenderPass::Command* RenderPass::generateCommandsImpl(RenderPass::CommandTypeFla
         cmd.info.hasMorphing = (bool)morphing.handle;
         cmd.info.hasSkinning = (bool)skinning.handle;
 
-        assert_invariant(cmd.info.hasHybridInstancing || cmd.info.instanceCount <= 1);
-
         // soaInstanceInfo[i].count is the number of instances the user has requested, either for
         // manual or hybrid instancing. Instanced stereo multiplies the number of instances by the
         // eye count.
diff --git a/filament/src/details/Material.cpp b/filament/src/details/Material.cpp
index 651b88cf0213..be8ca04be2ec 100644
--- a/filament/src/details/Material.cpp
+++ b/filament/src/details/Material.cpp
@@ -611,13 +611,10 @@ void FMaterial::createAndCacheProgram(Program&& p, Variant variant) const noexce
     FEngine const& engine = mEngine;
     DriverApi& driverApi = mEngine.getDriverApi();
 
-    bool const isSharedVariant =
-            (mMaterialDomain == MaterialDomain::SURFACE) &&
-            !mIsDefaultMaterial && !mHasCustomDepthShader &&
-            Variant::isValidDepthVariant(variant);
+    bool const isShared = isSharedVariant(variant);
 
     // Check if the default material has this program cached
-    if (isSharedVariant) {
+    if (isShared) {
         FMaterial const* const pDefaultMaterial = engine.getDefaultMaterial();
         if (pDefaultMaterial) {
             auto program = pDefaultMaterial->mCachedPrograms[variant.key];
@@ -636,7 +633,7 @@ void FMaterial::createAndCacheProgram(Program&& p, Variant variant) const noexce
     // If the default material doesn't already have this program cached, and all caching conditions
     // are met (Surface Domain and no custom depth shader), cache it now.
     // New Materials will inherit these program automatically.
-    if (isSharedVariant) {
+    if (isShared) {
         FMaterial const* const pDefaultMaterial = engine.getDefaultMaterial();
         if (pDefaultMaterial && !pDefaultMaterial->mCachedPrograms[variant.key]) {
             // set the tag to the default material name
diff --git a/filament/src/details/Material.h b/filament/src/details/Material.h
index eb578be3a3a7..5dd55e733ec8 100644
--- a/filament/src/details/Material.h
+++ b/filament/src/details/Material.h
@@ -156,6 +156,13 @@ class FMaterial : public Material {
         std::unique_lock<utils::Mutex> lock(mActiveProgramsLock);
         mActivePrograms.set(variant.key);
         lock.unlock();
+
+        if (isSharedVariant(variant)) {
+            FMaterial const* const pDefaultMaterial = mEngine.getDefaultMaterial();
+            if (pDefaultMaterial && pDefaultMaterial->mCachedPrograms[variant.key]) {
+                return pDefaultMaterial->getProgram(variant);
+            }
+        }
 #endif
         assert_invariant(mCachedPrograms[variant.key]);
         return mCachedPrograms[variant.key];
@@ -290,6 +297,11 @@ class FMaterial : public Material {
 
     void createAndCacheProgram(backend::Program&& p, Variant variant) const noexcept;
 
+    inline bool isSharedVariant(Variant variant) const {
+        return (mMaterialDomain == MaterialDomain::SURFACE) && !mIsDefaultMaterial &&
+               !mHasCustomDepthShader && Variant::isValidDepthVariant(variant);
+    }
+
     // try to order by frequency of use
     mutable std::array<backend::Handle<backend::HwProgram>, VARIANT_COUNT> mCachedPrograms;
     DescriptorSetLayout mPerViewDescriptorSetLayout;
diff --git a/filament/src/details/Texture.cpp b/filament/src/details/Texture.cpp
index 176907345b72..cff6d7e42a91 100644
--- a/filament/src/details/Texture.cpp
+++ b/filament/src/details/Texture.cpp
@@ -81,6 +81,7 @@ struct Texture::BuilderDetails {
     Usage mUsage = Usage::NONE;
     bool mHasBlitSrc = false;
     bool mTextureIsSwizzled = false;
+    bool mExternal = false;
     std::array<Swizzle, 4> mSwizzle = {
            Swizzle::CHANNEL_0, Swizzle::CHANNEL_1,
            Swizzle::CHANNEL_2, Swizzle::CHANNEL_3 };
@@ -136,6 +137,11 @@ Texture::Builder& Texture::Builder::import(intptr_t id) noexcept {
     return *this;
 }
 
+Texture::Builder& Texture::Builder::external() noexcept {
+    mImpl->mExternal = true;
+    return *this;
+}
+
 Texture::Builder& Texture::Builder::swizzle(Swizzle r, Swizzle g, Swizzle b, Swizzle a) noexcept {
     mImpl->mTextureIsSwizzled = true;
     mImpl->mSwizzle = { r, g, b, a };
@@ -154,6 +160,11 @@ Texture* Texture::Builder::build(Engine& engine) {
             (isProtectedTexturesSupported && useProtectedMemory) || !useProtectedMemory)
             << "Texture is PROTECTED but protected textures are not supported";
 
+    // SAMPLER_EXTERNAL implies imported.
+    if (mImpl->mTarget == SamplerType::SAMPLER_EXTERNAL) {
+        mImpl->mExternal = true;
+    }
+
     uint8_t maxLevelCount;
     switch (mImpl->mTarget) {
         case SamplerType::SAMPLER_2D:
@@ -174,7 +185,7 @@ Texture* Texture::Builder::build(Engine& engine) {
         mImpl->mUsage = TextureUsage::DEFAULT;
         if (mImpl->mLevels > 1 &&
             (mImpl->mWidth > 1 || mImpl->mHeight > 1) &&
-            mImpl->mTarget != SamplerType::SAMPLER_EXTERNAL) {
+            !mImpl->mExternal) {
             const bool formatMipmappable =
                     downcast(engine).getDriverApi().isTextureFormatMipmappable(mImpl->mFormat);
             if (formatMipmappable) {
@@ -243,9 +254,10 @@ FTexture::FTexture(FEngine& engine, const Builder& builder) {
     mSwizzle = builder->mSwizzle;
     mTextureIsSwizzled = builder->mTextureIsSwizzled;
     mHasBlitSrc = builder->mHasBlitSrc;
+    mExternal = builder->mExternal;
 
     bool const isImported = builder->mImportedId != 0;
-    if (mTarget == SamplerType::SAMPLER_EXTERNAL && !isImported) {
+    if (mExternal && !isImported) {
         // mHandle and mHandleForSampling will be created in setExternalImage()
         // If this Texture is used for sampling before setExternalImage() is called,
         // we'll lazily create a 1x1 placeholder texture.
@@ -318,8 +330,8 @@ void FTexture::setImage(FEngine& engine, size_t level,
             << "level=" << unsigned(level) << " is >= to levelCount=" << unsigned(mLevelCount)
             << ".";
 
-    FILAMENT_CHECK_PRECONDITION(mTarget != SamplerType::SAMPLER_EXTERNAL)
-            << "Texture SamplerType::SAMPLER_EXTERNAL not supported for this operation.";
+    FILAMENT_CHECK_PRECONDITION(!mExternal)
+            << "External Texture not supported for this operation.";
 
     FILAMENT_CHECK_PRECONDITION(mSampleCount <= 1) << "Operation not supported with multisample ("
                                                    << unsigned(mSampleCount) << ") texture.";
@@ -454,15 +466,14 @@ void FTexture::setImage(FEngine& engine, size_t level,
 }
 
 void FTexture::setExternalImage(FEngine& engine, void* image) noexcept {
-    if (mTarget != Sampler::SAMPLER_EXTERNAL) {
-        return;
-    }
+    FILAMENT_CHECK_PRECONDITION(mExternal) << "The texture must be external.";
+
     // The call to setupExternalImage is synchronous, and allows the driver to take ownership of the
     // external image on this thread, if necessary.
     auto& api = engine.getDriverApi();
     api.setupExternalImage(image);
 
-    auto texture = api.createTextureExternalImage(mFormat, mWidth, mHeight, mUsage, image);
+    auto texture = api.createTextureExternalImage(mTarget, mFormat, mWidth, mHeight, mUsage, image);
 
     if (mTextureIsSwizzled) {
         auto const& s = mSwizzle;
@@ -475,9 +486,8 @@ void FTexture::setExternalImage(FEngine& engine, void* image) noexcept {
 }
 
 void FTexture::setExternalImage(FEngine& engine, void* image, size_t plane) noexcept {
-    if (mTarget != Sampler::SAMPLER_EXTERNAL) {
-        return;
-    }
+    FILAMENT_CHECK_PRECONDITION(mExternal) << "The texture must be external.";
+
     // The call to setupExternalImage is synchronous, and allows the driver to take ownership of
     // the external image on this thread, if necessary.
     auto& api = engine.getDriverApi();
@@ -497,9 +507,7 @@ void FTexture::setExternalImage(FEngine& engine, void* image, size_t plane) noex
 }
 
 void FTexture::setExternalStream(FEngine& engine, FStream* stream) noexcept {
-    if (mTarget != Sampler::SAMPLER_EXTERNAL) {
-        return;
-    }
+    FILAMENT_CHECK_PRECONDITION(mExternal) << "The texture must be external.";
 
     auto& api = engine.getDriverApi();
     auto texture = api.createTexture(
@@ -524,7 +532,7 @@ void FTexture::setExternalStream(FEngine& engine, FStream* stream) noexcept {
 }
 
 void FTexture::generateMipmaps(FEngine& engine) const noexcept {
-    FILAMENT_CHECK_PRECONDITION(mTarget != SamplerType::SAMPLER_EXTERNAL)
+    FILAMENT_CHECK_PRECONDITION(!mExternal)
             << "External Textures are not mipmappable.";
 
     FILAMENT_CHECK_PRECONDITION(mTarget != SamplerType::SAMPLER_3D)
@@ -544,12 +552,11 @@ void FTexture::generateMipmaps(FEngine& engine) const noexcept {
 }
 
 bool FTexture::textureHandleCanMutate() const noexcept {
-    return (any(mUsage & Usage::SAMPLEABLE) && mLevelCount > 1) ||
-            mTarget == SamplerType::SAMPLER_EXTERNAL;
+    return (any(mUsage & Usage::SAMPLEABLE) && mLevelCount > 1) || mExternal;
 }
 
 void FTexture::updateLodRange(uint8_t baseLevel, uint8_t levelCount) noexcept {
-    assert_invariant(mTarget != SamplerType::SAMPLER_EXTERNAL);
+    assert_invariant(!mExternal);
     if (any(mUsage & Usage::SAMPLEABLE) && mLevelCount > 1) {
         auto& range = mLodRange;
         uint8_t const last = int8_t(baseLevel + levelCount);
@@ -601,7 +608,7 @@ backend::Handle<backend::HwTexture> FTexture::createPlaceholderTexture(
 }
 
 backend::Handle<backend::HwTexture> FTexture::getHwHandleForSampling() const noexcept {
-    if (UTILS_UNLIKELY(mTarget == SamplerType::SAMPLER_EXTERNAL && !mHandleForSampling)) {
+    if (UTILS_UNLIKELY(mExternal && !mHandleForSampling)) {
         return setHandleForSampling(createPlaceholderTexture(*mDriver));
     }
     auto const& range = mLodRange;
@@ -610,9 +617,10 @@ backend::Handle<backend::HwTexture> FTexture::getHwHandleForSampling() const noe
     if (UTILS_UNLIKELY(lodRangeChanged)) {
         activeRange = range;
         if (range.empty() || hasAllLods(range)) {
-            setHandleForSampling(mHandle);
+            std::ignore = setHandleForSampling(mHandle);
         } else {
-            setHandleForSampling(mDriver->createTextureView(mHandle, range.first, range.size()));
+            std::ignore = setHandleForSampling(mDriver->createTextureView(
+                mHandle, range.first, range.size()));
         }
     }
     return mHandleForSampling;
diff --git a/filament/src/details/Texture.h b/filament/src/details/Texture.h
index 6bf04dae4ac2..2131988c84c9 100644
--- a/filament/src/details/Texture.h
+++ b/filament/src/details/Texture.h
@@ -173,7 +173,8 @@ class FTexture : public Texture {
     // Indicates whether the user has set the TextureUsage::BLIT_SRC usage. This will be used to
     // temporarily validate whether this texture can be used for readPixels.
     bool mHasBlitSrc = false;
-    // there is 5 bytes of padding here
+    bool mExternal = false;
+    // there is 4 bytes of padding here
 
     FStream* mStream = nullptr; // only needed for streaming textures
 };
diff --git a/filament/src/ds/DescriptorSet.cpp b/filament/src/ds/DescriptorSet.cpp
index 9d41b20a33f6..caa433ad46ca 100644
--- a/filament/src/ds/DescriptorSet.cpp
+++ b/filament/src/ds/DescriptorSet.cpp
@@ -149,7 +149,7 @@ void DescriptorSet::setSampler(
 
 DescriptorSet DescriptorSet::duplicate(DescriptorSetLayout const& layout) const noexcept {
     DescriptorSet set{layout};
-    memcpy(set.mDescriptors.data(), mDescriptors.data(), mDescriptors.size() * sizeof(Desc));
+    set.mDescriptors = mDescriptors; // Use the vector's assignment operator
     set.mDirty = mDirty;
     set.mValid = mValid;
     return set;
diff --git a/filament/src/materials/antiAliasing/taa.mat b/filament/src/materials/antiAliasing/taa.mat
index b5430378c70f..86f55508e472 100644
--- a/filament/src/materials/antiAliasing/taa.mat
+++ b/filament/src/materials/antiAliasing/taa.mat
@@ -127,7 +127,8 @@ float lumaYCoCg(const vec3 c) {
 }
 
 float luma(const vec3 c) {
-    return materialConstants_useYCoCg ? lumaYCoCg(c) : lumaRGB(c);
+    return (materialConstants_useYCoCg && materialConstants_boxClipping != BOX_CLIPPING_NONE) ?
+            lumaYCoCg(c) : lumaRGB(c);
 }
 
 vec3 tonemap(const vec3 c) {
@@ -278,10 +279,6 @@ void postProcess(inout PostProcessInputs postProcess) {
         history = textureLod(materialParams_history, uv.zw, 0.0);
     }
 
-    if (materialConstants_useYCoCg) {
-        history.rgb = RGB_YCoCg(history.rgb);
-    }
-
     highp vec2 size = vec2(textureSize(materialParams_color, 0));
     highp vec2 p = (floor(uv.xy * size) + 0.5) / size;
     vec4 filtered = textureLod(materialParams_color, p, 0.0);
@@ -297,47 +294,46 @@ void postProcess(inout PostProcessInputs postProcess) {
         s[6] = textureLodOffset(materialParams_color, p, 0.0, ivec2(-1,  1)).rgb;
         s[7] = textureLodOffset(materialParams_color, p, 0.0, ivec2( 0,  1)).rgb;
         s[8] = textureLodOffset(materialParams_color, p, 0.0, ivec2( 1,  1)).rgb;
-        if (materialConstants_useYCoCg) {
-            for (int i = 0; i < 9; i++) {
-                s[i] = RGB_YCoCg(s[i]);
-            }
-        }
     }
 
-    vec2 subPixelOffset = p - uv.xy;  // +/- [0.25, 0.25]
-    float confidence = materialConstants_upscaling ? 0.0 : 1.0;
+    int j = 0;
+    float confidence = 1.0;
+    if (materialConstants_upscaling) {
+        highp vec2 subPixelOffset = (p - uv.xy) * size;  // +/- [0.25, 0.25]
+
+        // we reduce the contribution of a sample based on the distance
+        // to the high resolution pixel center
+        const float cutoff = 0.5;
+        highp float l = length(materialParams.jitter - subPixelOffset) / cutoff;
+        confidence = saturate(1.0 - l * l);
+
+        if (materialConstants_filterInput) {
+            int jxp = subPixelOffset.y > 0.0 ? 1 : 2;
+            int jxn = subPixelOffset.y > 0.0 ? 0 : 3;
+            j = subPixelOffset.x > 0.0 ? jxp : jxn;
+        }
+    }
 
     if (materialConstants_filterInput) {
         // unjitter/filter input
-        // figure out which set of coeficients to use
-        filtered = vec4(0, 0, 0, filtered.a);
-        if (materialConstants_upscaling) {
-            int jxp = subPixelOffset.y > 0.0 ? 3 : 0;
-            int jxn = subPixelOffset.y > 0.0 ? 2 : 1;
-            int j   = subPixelOffset.x > 0.0 ? jxp : jxn;
-            for (int i = 0; i < 9; i++) {
-                float w = materialParams.filterWeights[i][j];
-                filtered.rgb += s[i] * w;
-                confidence = max(confidence, w);
-            }
-        } else {
-            for (int i = 0; i < 9; i++) {
-                float w = materialParams.filterWeights[i][0];
-                filtered.rgb += s[i] * w;
-            }
-        }
-    } else {
-        if (materialConstants_useYCoCg) {
-            filtered.rgb = RGB_YCoCg(filtered.rgb);
-        }
-        if (materialConstants_upscaling) {
-            confidence = float(materialParams.jitter.x * subPixelOffset.x > 0.0 &&
-                               materialParams.jitter.y * subPixelOffset.y > 0.0);
+        filtered = vec4(vec3(0), filtered.a);
+        for (int i = 0; i < 9; i++) {
+            float w = materialParams.filterWeights[i][j];
+            filtered.rgb += s[i] * w;
         }
+        filtered.rgb = max(filtered.rgb, vec3(0));
     }
 
     // build the history clamping box
     if (materialConstants_boxClipping != BOX_CLIPPING_NONE) {
+        if (materialConstants_useYCoCg) {
+            history.rgb = RGB_YCoCg(history.rgb);
+            filtered.rgb = RGB_YCoCg(filtered.rgb);
+            for (int i = 0; i < 9; i++) {
+                s[i] = RGB_YCoCg(s[i]);
+            }
+        }
+
         vec3 boxmin;
         vec3 boxmax;
         if (materialConstants_boxType == BOX_TYPE_AABB ||
@@ -346,7 +342,7 @@ void postProcess(inout PostProcessInputs postProcess) {
             boxmax = max(s[4], max(max(s[1], s[3]), max(s[5], s[7])));
             vec3 box9min = min(boxmin, min(min(s[0], s[2]), min(s[6], s[8])));
             vec3 box9max = max(boxmax, max(max(s[0], s[2]), max(s[6], s[8])));
-            // round the corners of the 3x3 box
+            // round the corners of the 3x3 box, giving less importance to the corner samples
             boxmin = (boxmin + box9min) * 0.5;
             boxmax = (boxmax + box9max) * 0.5;
         }
@@ -388,9 +384,11 @@ void postProcess(inout PostProcessInputs postProcess) {
     }
 
     // go back to RGB space before tonemapping
-    if (materialConstants_useYCoCg) {
-        filtered.rgb = YCoCg_RGB(filtered.rgb);
-        history.rgb = YCoCg_RGB(history.rgb);
+    if (materialConstants_boxClipping != BOX_CLIPPING_NONE) {
+        if (materialConstants_useYCoCg) {
+            filtered.rgb = YCoCg_RGB(filtered.rgb);
+            history.rgb = YCoCg_RGB(history.rgb);
+        }
     }
 
     // tonemap before mixing
diff --git a/ios/CocoaPods/Filament.podspec b/ios/CocoaPods/Filament.podspec
index c6378573e361..1133525c5a70 100644
--- a/ios/CocoaPods/Filament.podspec
+++ b/ios/CocoaPods/Filament.podspec
@@ -1,12 +1,12 @@
 Pod::Spec.new do |spec|
   spec.name = "Filament"
-  spec.version = "1.56.5"
+  spec.version = "1.56.6"
   spec.license = { :type => "Apache 2.0", :file => "LICENSE" }
   spec.homepage = "https://google.github.io/filament"
   spec.authors = "Google LLC."
   spec.summary = "Filament is a real-time physically based rendering engine for Android, iOS, Windows, Linux, macOS, and WASM/WebGL."
   spec.platform = :ios, "11.0"
-  spec.source = { :http => "https://github.com/google/filament/releases/download/v1.56.5/filament-v1.56.5-ios.tgz" }
+  spec.source = { :http => "https://github.com/google/filament/releases/download/v1.56.6/filament-v1.56.6-ios.tgz" }
 
   # Fix linking error with Xcode 12; we do not yet support the simulator on Apple silicon.
   spec.pod_target_xcconfig = {
diff --git a/libs/bluevk/include/bluevk/BlueVK.h b/libs/bluevk/include/bluevk/BlueVK.h
index a57c528a2542..4fb61191a321 100644
--- a/libs/bluevk/include/bluevk/BlueVK.h
+++ b/libs/bluevk/include/bluevk/BlueVK.h
@@ -40,7 +40,7 @@
 
     #if defined(__ANDROID__)
     #define VK_USE_PLATFORM_ANDROID_KHR 1
-    #elif defined(IOS)
+    #elif defined(FILAMENT_IOS)
     #define VK_USE_PLATFORM_IOS_MVK 1
     #elif defined(__linux__)
     #if defined(FILAMENT_SUPPORTS_XCB)
diff --git a/libs/fgviewer/CMakeLists.txt b/libs/fgviewer/CMakeLists.txt
new file mode 100644
index 000000000000..cf6bdb526df7
--- /dev/null
+++ b/libs/fgviewer/CMakeLists.txt
@@ -0,0 +1,71 @@
+cmake_minimum_required(VERSION 3.19)
+project(fgviewer C ASM)
+
+set(TARGET fgviewer)
+set(PUBLIC_HDR_DIR include)
+
+if (CMAKE_CROSSCOMPILING)
+    include(${IMPORT_EXECUTABLES})
+endif()
+
+# ==================================================================================================
+# Sources and headers
+# ==================================================================================================
+
+set(PUBLIC_HDRS
+    include/fgviewer/DebugServer.h
+    include/fgviewer/JsonWriter.h
+)
+
+set(SRCS
+    src/ApiHandler.cpp
+    src/ApiHandler.h
+    src/DebugServer.cpp
+)
+
+# ==================================================================================================
+# Include and target definitions
+# ==================================================================================================
+
+include_directories(${PUBLIC_HDR_DIR})
+
+add_library(${TARGET} STATIC ${PUBLIC_HDRS} ${SRCS})
+
+target_link_libraries(${TARGET} PUBLIC
+        civetweb
+        utils
+)
+
+target_include_directories(${TARGET} PRIVATE ${filamat_SOURCE_DIR}/src)
+
+target_include_directories(${TARGET} PUBLIC ${PUBLIC_HDR_DIR})
+set_target_properties(${TARGET} PROPERTIES FOLDER Libs)
+
+# ==================================================================================================
+# Compiler flags
+# ==================================================================================================
+
+if (MSVC)
+else()
+    target_compile_options(${TARGET} PRIVATE -Wno-deprecated-register)
+endif()
+
+# ==================================================================================================
+# Installation
+# ==================================================================================================
+
+# matdbg has dependencies on non-installed libraries. Here we bundle them all together into a single
+# library that gets copied into the installation folder so users are only required to link against
+# matdbg.
+set(FGVIEWER_DEPS
+    fgviewer
+    civetweb
+    )
+
+set(FGVIEWER_COMBINED_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/libfgviewer_combined.a")
+combine_static_libs(fgviewer "${FGVIEWER_COMBINED_OUTPUT}" "${FGVIEWER_DEPS}")
+
+set(FGVIEWER_LIB_NAME ${CMAKE_STATIC_LIBRARY_PREFIX}fgviewer${CMAKE_STATIC_LIBRARY_SUFFIX})
+install(FILES "${FGVIEWER_COMBINED_OUTPUT}" DESTINATION lib/${DIST_DIR} RENAME ${FGVIEWER_LIB_NAME})
+# We do not need fgviewer headers in the install directory
+# install(DIRECTORY ${PUBLIC_HDR_DIR}/fgviewer DESTINATION include)
diff --git a/libs/fgviewer/include/fgviewer/DebugServer.h b/libs/fgviewer/include/fgviewer/DebugServer.h
new file mode 100644
index 000000000000..ef0544833347
--- /dev/null
+++ b/libs/fgviewer/include/fgviewer/DebugServer.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FGVIEWER_DEBUGSERVER_H
+#define FGVIEWER_DEBUGSERVER_H
+
+#include <utils/CString.h>
+#include <utils/Mutex.h>
+
+#include <unordered_map>
+#include <vector>
+
+class CivetServer;
+
+namespace filament::fgviewer {
+
+using FrameGraphInfoKey = uint32_t;
+
+struct FrameGraphPassInfo {
+    utils::CString pass_name;
+    // TODO: Add struct detail properties
+};
+
+struct FrameGraphInfo {
+    utils::CString view_name;
+    std::vector<FrameGraphPassInfo> passes;
+};
+
+/**
+ * Server-side frame graph debugger.
+ *
+ * This class manages an HTTP server. It receives frame graph packages from the Filament C++ engine or
+ * from a standalone tool such as fginfo.
+ */
+class DebugServer {
+public:
+    static std::string_view const kSuccessHeader;
+    static std::string_view const kErrorHeader;
+
+    DebugServer(int port);
+    ~DebugServer();
+
+    /**
+     * Notifies the debugger that a new view has been added.
+     */
+    void addView(const utils::CString& name, FrameGraphInfo info);
+
+    /**
+     * Notifies the debugger that the given view has been deleted.
+     */
+    void removeView(const utils::CString& name);
+
+    /**
+     * Updates the information for a given view.
+     */
+    void updateView(const utils::CString& name, FrameGraphInfo info);
+
+    bool isReady() const { return mServer; }
+
+private:
+    CivetServer* mServer;
+
+    std::unordered_map<FrameGraphInfoKey, FrameGraphInfo> mViews;
+    mutable utils::Mutex mViewsMutex;
+
+    class FileRequestHandler* mFileHandler = nullptr;
+    class ApiHandler* mApiHandler = nullptr;
+
+    friend class FileRequestHandler;
+    friend class ApiHandler;
+};
+
+} // namespace filament::fgviewer
+
+#endif  // FGVIEWER_DEBUGSERVER_H
diff --git a/libs/fgviewer/include/fgviewer/JsonWriter.h b/libs/fgviewer/include/fgviewer/JsonWriter.h
new file mode 100644
index 000000000000..de9c188eee2b
--- /dev/null
+++ b/libs/fgviewer/include/fgviewer/JsonWriter.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FGVIEWER_JSONWRITER_H
+#define FGVIEWER_JSONWRITER_H
+
+#include <utils/CString.h>
+
+namespace filament::fgviewer {
+
+struct FrameGraphInfo;
+
+// This class generates portions of JSON messages that are sent to the web client.
+// Note that some portions of these JSON strings are generated by directly in DebugServer,
+// as well as CommonWriter.
+class JsonWriter {
+public:
+
+    // Retrieves the most recently generated string.
+    const char* getJsonString() const;
+    size_t getJsonSize() const;
+
+    // Generates a JSON string describing the given FrameGraphInfo.
+    bool writeFrameGraphInfo(const FrameGraphInfo& frameGraph);
+
+private:
+    utils::CString mJsonString;
+};
+
+} // namespace filament::fgviewer
+
+#endif  // FGVIEWER_JSONWRITER_H
diff --git a/libs/fgviewer/src/ApiHandler.cpp b/libs/fgviewer/src/ApiHandler.cpp
new file mode 100644
index 000000000000..729820d4047c
--- /dev/null
+++ b/libs/fgviewer/src/ApiHandler.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include "ApiHandler.h"
+
+#include <fgviewer/DebugServer.h>
+
+#include <utils/FixedCapacityVector.h>
+#include <utils/Log.h>
+
+#include <CivetServer.h>
+
+namespace filament::fgviewer {
+
+using namespace std::chrono_literals;
+
+namespace {
+
+auto const& kSuccessHeader = DebugServer::kSuccessHeader;
+auto const& kErrorHeader = DebugServer::kErrorHeader;
+
+auto const error = [](int line, std::string const& uri) {
+    utils::slog.e << "[fgviewer] DebugServer: 404 at line " << line << ": " << uri << utils::io::endl;
+    return false;
+};
+
+} // anonymous
+
+bool ApiHandler::handleGetApiFgInfo(struct mg_connection* conn,
+        struct mg_request_info const* request) {
+    auto const softError = [conn, request](char const* msg) {
+        utils::slog.e << "[fgviewer] DebugServer: " << msg << ": " << request->query_string << utils::io::endl;
+        mg_printf(conn, kErrorHeader.data(), "application/txt");
+        mg_write(conn, msg, strlen(msg));
+        return true;
+    };
+
+    // TODO: Implement the method
+    return true;
+}
+
+void ApiHandler::addFrameGraph(FrameGraphInfo const* framegraph) {
+    // TODO: Implement the method
+}
+
+
+bool ApiHandler::handleGet(CivetServer* server, struct mg_connection* conn) {
+    struct mg_request_info const* request = mg_get_request_info(conn);
+    std::string const& uri = request->local_uri;
+
+    // TODO: Implement the method
+    return true;
+}
+
+} // filament::fgviewer
diff --git a/libs/fgviewer/src/ApiHandler.h b/libs/fgviewer/src/ApiHandler.h
new file mode 100644
index 000000000000..b0ed9e785d39
--- /dev/null
+++ b/libs/fgviewer/src/ApiHandler.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FGVIEWER_APIHANDLER_H
+#define FGVIEWER_APIHANDLER_H
+
+#include <CivetServer.h>
+
+namespace filament::fgviewer {
+
+class DebugServer;
+struct FrameGraphInfo;
+
+// Handles the following REST requests, where {id} is an 8-digit hex string.
+//
+//    GET /api/framegraphs
+//    GET /api/framegraph?fg={viewname}
+//
+class ApiHandler : public CivetHandler {
+public:
+    explicit ApiHandler(DebugServer* server)
+        : mServer(server) {}
+    ~ApiHandler() = default;
+
+    bool handleGet(CivetServer* server, struct mg_connection* conn);
+    void addFrameGraph(FrameGraphInfo const* frameGraph);
+
+private:
+    bool handleGetApiFgInfo(struct mg_connection* conn, struct mg_request_info const* request);
+
+    DebugServer* mServer;
+};
+
+} // filament::fgviewer
+
+#endif // FGVIEWER_APIHANDLER_H
diff --git a/libs/fgviewer/src/DebugServer.cpp b/libs/fgviewer/src/DebugServer.cpp
new file mode 100644
index 000000000000..ce1ccaa36b2e
--- /dev/null
+++ b/libs/fgviewer/src/DebugServer.cpp
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <fgviewer/DebugServer.h>
+
+#include "ApiHandler.h"
+
+#include <CivetServer.h>
+
+#include <utils/FixedCapacityVector.h>
+#include <utils/Hash.h>
+#include <utils/Log.h>
+
+#include <string>
+#include <string_view>
+
+namespace filament::fgviewer {
+
+namespace {
+std::string const BASE_URL = "libs/fgviewer/web";
+
+FrameGraphInfoKey getKeybyString(const utils::CString &input,
+                                              uint32_t seed) {
+    return utils::hash::murmurSlow(reinterpret_cast<uint8_t const*>(
+        input.c_str()), input.size(), 0);
+}
+} // anonymous
+
+using namespace utils;
+
+std::string_view const DebugServer::kSuccessHeader =
+        "HTTP/1.1 200 OK\r\nContent-Type: %s\r\n"
+        "Connection: close\r\n\r\n";
+
+std::string_view const DebugServer::kErrorHeader =
+        "HTTP/1.1 404 Not Found\r\nContent-Type: %s\r\n"
+        "Connection: close\r\n\r\n";
+
+class FileRequestHandler : public CivetHandler {
+public:
+    FileRequestHandler(DebugServer* server) : mServer(server) {}
+    bool handleGet(CivetServer *server, struct mg_connection *conn) {
+        auto const& kSuccessHeader = DebugServer::kSuccessHeader;
+        struct mg_request_info const* request = mg_get_request_info(conn);
+        std::string uri(request->request_uri);
+        if (uri == "/") {
+            uri = "/index.html";
+        }
+
+        if (uri == "/index.html" || uri == "/app.js" || uri == "/api.js") {
+            mg_send_file(conn, (BASE_URL + uri).c_str());
+            return true;
+        }
+        slog.e << "[fgviewer] DebugServer: bad request at line " <<  __LINE__ << ": " << uri << io::endl;
+        return false;
+    }
+private:
+    DebugServer* mServer;
+};
+
+DebugServer::DebugServer(int port) {
+    // By default the server spawns 50 threads so we override this to 10. According to the civetweb
+    // documentation, "it is recommended to use num_threads of at least 5, since browsers often
+    /// establish multiple connections to load a single web page, including all linked documents
+    // (CSS, JavaScript, images, ...)."  If this count is too small, the web app basically hangs.
+    const char* kServerOptions[] = {
+        "listening_ports", "8085",
+        "num_threads", "10",
+        "error_log_file", "civetweb.txt",
+        nullptr
+    };
+    std::string portString = std::to_string(port);
+    kServerOptions[1] = portString.c_str();
+
+    mServer = new CivetServer(kServerOptions);
+    if (!mServer->getContext()) {
+        delete mServer;
+        mServer = nullptr;
+        slog.e << "[fgviewer] Unable to start DebugServer, see civetweb.txt for details." << io::endl;
+        return;
+    }
+
+    mFileHandler = new FileRequestHandler(this);
+    mApiHandler = new ApiHandler(this);
+
+    mServer->addHandler("/api", mApiHandler);
+    mServer->addHandler("", mFileHandler);
+
+    slog.i << "[fgviewer] DebugServer listening at http://localhost:" << port << io::endl;
+}
+
+DebugServer::~DebugServer() {
+    mServer->close();
+
+    delete mFileHandler;
+    delete mApiHandler;
+    delete mServer;
+}
+
+void DebugServer::addView(const utils::CString &name, FrameGraphInfo info) {
+    std::unique_lock<utils::Mutex> lock(mViewsMutex);
+    const FrameGraphInfoKey key = getKeybyString(name, 0);
+    mViews.insert({key, info});
+}
+
+void DebugServer::removeView(const utils::CString& name) {
+    std::unique_lock<utils::Mutex> lock(mViewsMutex);
+    const FrameGraphInfoKey key = getKeybyString(name, 0);
+    mViews.erase(key);
+}
+
+void DebugServer::updateView(const utils::CString& name, FrameGraphInfo info) {
+    std::unique_lock<utils::Mutex> lock(mViewsMutex);
+    const FrameGraphInfoKey key = getKeybyString(name, 0);
+    mViews[key] = info;
+}
+
+} // namespace filament::fgviewer
diff --git a/libs/filamentapp/src/FilamentApp.cpp b/libs/filamentapp/src/FilamentApp.cpp
index 4b7bbd8c33d3..e47c95c79a1a 100644
--- a/libs/filamentapp/src/FilamentApp.cpp
+++ b/libs/filamentapp/src/FilamentApp.cpp
@@ -645,7 +645,7 @@ FilamentApp::Window::Window(FilamentApp* filamentApp,
 
         // This mirrors the logic for choosing a backend given compile-time flags and client having
         // provided DEFAULT as the backend (see PlatformFactory.cpp)
-        #if !defined(__EMSCRIPTEN__) && !defined(__ANDROID__) && !defined(IOS) && \
+        #if !defined(__EMSCRIPTEN__) && !defined(__ANDROID__) && !defined(FILAMENT_IOS) && \
             !defined(__APPLE__) && defined(FILAMENT_DRIVER_SUPPORTS_VULKAN)
             if (backend == Engine::Backend::DEFAULT) {
                 backend = Engine::Backend::VULKAN;
diff --git a/libs/gltfio/src/Animator.cpp b/libs/gltfio/src/Animator.cpp
index 0d8b667644b1..7b1bd6eb2508 100644
--- a/libs/gltfio/src/Animator.cpp
+++ b/libs/gltfio/src/Animator.cpp
@@ -408,6 +408,9 @@ void AnimatorImpl::addChannels(const FixedCapacityVector<Entity>& nodeMap,
     const Sampler* samplers = dst.samplers.data();
     for (cgltf_size j = 0, nchans = srcAnim.channels_count; j < nchans; ++j) {
         const cgltf_animation_channel& srcChannel = srcChannels[j];
+        if (!srcChannel.target_node) {
+            continue;
+        }
         Entity targetEntity = nodeMap[srcChannel.target_node - nodes];
         if (UTILS_UNLIKELY(!targetEntity)) {
             if (GLTFIO_VERBOSE) {
diff --git a/libs/gltfio/src/AssetLoader.cpp b/libs/gltfio/src/AssetLoader.cpp
index cf3007a67f64..2e3439a9a7da 100644
--- a/libs/gltfio/src/AssetLoader.cpp
+++ b/libs/gltfio/src/AssetLoader.cpp
@@ -1733,7 +1733,7 @@ void FAssetLoader::importSkins(FFilamentInstance* instance, const cgltf_data* gl
 }
 
 bool AssetConfigurationExtended::isSupported() {
-#if defined(__ANDROID__) || defined(IOS) || defined(__EMSCRIPTEN__)
+#if defined(__ANDROID__) || defined(FILAMENT_IOS) || defined(__EMSCRIPTEN__)
     return false;
 #else
     return true;
diff --git a/libs/gltfio/src/FFilamentAsset.h b/libs/gltfio/src/FFilamentAsset.h
index a1401c37ccb0..1648ad0d2c38 100644
--- a/libs/gltfio/src/FFilamentAsset.h
+++ b/libs/gltfio/src/FFilamentAsset.h
@@ -60,7 +60,7 @@
 #define GLTFIO_WARN(msg) slog.w << msg << io::endl
 #endif
 
-#if defined(__EMSCRIPTEN__) || defined(__ANDROID__) || defined(IOS)
+#if defined(__EMSCRIPTEN__) || defined(__ANDROID__) || defined(FILAMENT_IOS)
 #define GLTFIO_USE_FILESYSTEM 0
 #else
 #define GLTFIO_USE_FILESYSTEM 1
diff --git a/libs/matdbg/CMakeLists.txt b/libs/matdbg/CMakeLists.txt
index e5805854808d..566aec3fd31e 100644
--- a/libs/matdbg/CMakeLists.txt
+++ b/libs/matdbg/CMakeLists.txt
@@ -31,6 +31,8 @@ set(SRCS
     src/ShaderReplacer.cpp
     src/ShaderExtractor.cpp
     src/ShaderInfo.cpp
+    src/SourceFormatter.cpp
+    src/SourceFormatter.h
     src/TextWriter.cpp
 )
 
diff --git a/libs/matdbg/src/ApiHandler.cpp b/libs/matdbg/src/ApiHandler.cpp
index 82e27fa53ac7..c9ef42c0ee0b 100644
--- a/libs/matdbg/src/ApiHandler.cpp
+++ b/libs/matdbg/src/ApiHandler.cpp
@@ -43,19 +43,6 @@ namespace {
 auto const& kSuccessHeader = DebugServer::kSuccessHeader;
 auto const& kErrorHeader = DebugServer::kErrorHeader;
 
-void spirvToAsm(struct mg_connection* conn, uint32_t const* spirv, size_t size) {
-    auto spirvDisassembly = ShaderExtractor::spirvToText(spirv, size / 4);
-    mg_printf(conn, kSuccessHeader.data(), "application/txt");
-    mg_write(conn, spirvDisassembly.c_str(), spirvDisassembly.size());
-}
-
-void spirvToGlsl(ShaderModel shaderModel, struct mg_connection* conn, uint32_t const* spirv,
-        size_t size) {
-    auto glsl = ShaderExtractor::spirvToGLSL(shaderModel, spirv, size / 4);
-    mg_printf(conn, kSuccessHeader.data(), "application/txt");
-    mg_printf(conn, glsl.c_str(), glsl.size());
-}
-
 } // anonymous
 
 using filaflat::ChunkContainer;
@@ -145,8 +132,10 @@ bool ApiHandler::handleGetApiShader(struct mg_connection* conn,
         filaflat::ShaderContent content;
         extractor.getShader(item.shaderModel, item.variant, item.pipelineStage, content);
 
+        std::string const shader = mFormatter.format((char const*) content.data());
         mg_printf(conn, kSuccessHeader.data(), "application/txt");
-        mg_write(conn, content.data(), content.size() - 1);
+        mg_write(conn, shader.c_str(), shader.size());
+
         return true;
     }
 
@@ -171,12 +160,19 @@ bool ApiHandler::handleGetApiShader(struct mg_connection* conn,
         extractor.getShader(item.shaderModel, item.variant, item.pipelineStage, content);
 
         if (language == spirv) {
-            spirvToAsm(conn, (uint32_t const*) content.data(), content.size());
+            auto spirvDisassembly = ShaderExtractor::spirvToText((uint32_t const*) content.data(),
+                    content.size() / 4);
+            mg_printf(conn, kSuccessHeader.data(), "application/txt");
+            mg_write(conn, spirvDisassembly.c_str(), spirvDisassembly.size());
             return true;
         }
 
         if (language == glsl) {
-            spirvToGlsl(item.shaderModel, conn, (uint32_t const*) content.data(), content.size());
+            auto glsl = ShaderExtractor::spirvToGLSL(item.shaderModel,
+                    (uint32_t const*) content.data(), content.size() / 4);
+            std::string const shader = mFormatter.format((char const*) glsl.c_str());
+            mg_printf(conn, kSuccessHeader.data(), "application/txt");
+            mg_printf(conn, shader.c_str(), shader.size());
             return true;
         }
 
@@ -204,8 +200,9 @@ bool ApiHandler::handleGetApiShader(struct mg_connection* conn,
         extractor.getShader(item.shaderModel, item.variant, item.pipelineStage, content);
 
         if (language == msl) {
+            std::string const shader = mFormatter.format((char const*) content.data());
             mg_printf(conn, kSuccessHeader.data(), "application/txt");
-            mg_write(conn, content.data(), content.size() - 1);
+            mg_write(conn, shader.c_str(), shader.size());
             return true;
         }
 
diff --git a/libs/matdbg/src/ApiHandler.h b/libs/matdbg/src/ApiHandler.h
index 81aaa7c734c5..353326a7dc7d 100644
--- a/libs/matdbg/src/ApiHandler.h
+++ b/libs/matdbg/src/ApiHandler.h
@@ -17,6 +17,8 @@
 #ifndef MATDBG_APIHANDLER_H
 #define MATDBG_APIHANDLER_H
 
+#include "SourceFormatter.h"
+
 #include <mutex>
 #include <condition_variable>
 #include <atomic>
@@ -63,6 +65,8 @@ class ApiHandler : public CivetHandler {
     // will always block until statusMaterialId is updated again. The client is expected to keep
     // calling /api/status (a constant "pull" to simulate a push).
     std::atomic<uint64_t> mCurrentStatus = 0;
+
+    SourceFormatter mFormatter;
 };
 
 } // filament::matdbg
diff --git a/libs/matdbg/src/DebugServer.cpp b/libs/matdbg/src/DebugServer.cpp
index 96c9538620e7..e8efb0b22745 100644
--- a/libs/matdbg/src/DebugServer.cpp
+++ b/libs/matdbg/src/DebugServer.cpp
@@ -193,8 +193,12 @@ DebugServer::addMaterial(const CString& name, const void* data, size_t size, voi
         return {};
     }
 
-    const uint32_t seed = 42;
-    const MaterialKey key = utils::hash::murmurSlow((const uint8_t*) data, size, seed);
+    // Note that it's possible to have two materials with the exact same content (however wasteful),
+    // but they refer to different instantiation of FMaterial. Hence we hash on userdata and the
+    // material data.
+    constexpr uint32_t seed = 42;
+    uint64_t dataSpace[2] = {(uint64_t) data, (uint64_t) userdata};
+    uint32_t const key = utils::hash::murmurSlow((uint8_t const*) dataSpace, sizeof(dataSpace), seed);
 
     // Retain a copy of the package to permit queries after the client application has
     // freed up the original material package.
diff --git a/libs/matdbg/src/ShaderReplacer.cpp b/libs/matdbg/src/ShaderReplacer.cpp
index 2a99ee0db567..8a457e598c98 100644
--- a/libs/matdbg/src/ShaderReplacer.cpp
+++ b/libs/matdbg/src/ShaderReplacer.cpp
@@ -377,7 +377,7 @@ void BlobIndex::writeChunks(ostream& stream) {
     for (auto& record : mShaderRecords) {
         const auto& src = mDataBlobs[record.dictionaryIndex];
         assert(src.size() % 4 == 0);
-        const uint32_t* ptr = (const uint32_t*) src.data();
+        uint8_t const* ptr = (uint8_t const*) src.data();
         record.dictionaryIndex = blobs.addBlob(vector<uint8_t>(ptr, ptr + src.size()));
     }
 
diff --git a/libs/matdbg/src/SourceFormatter.cpp b/libs/matdbg/src/SourceFormatter.cpp
new file mode 100644
index 000000000000..c068a34f4b43
--- /dev/null
+++ b/libs/matdbg/src/SourceFormatter.cpp
@@ -0,0 +1,80 @@
+/*
+ * 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.
+ */
+
+#include "SourceFormatter.h"
+
+#include <utils/Log.h>
+
+#include <cstdio>
+#include <sstream>
+
+namespace filament::matdbg {
+
+#if defined(__linux__) || defined(__APPLE__)
+std::string SourceFormatter::format(char const* source) {
+    std::string const TMP_FILENAME = "/tmp/matdbg-tmp-src.cpp";
+
+    std::string original(source);
+    FILE* fp;
+    fp = fopen(TMP_FILENAME.c_str(), "w");
+    if (!fp) {
+        return original;
+    }
+    fputs(original.c_str(), fp);
+    fflush(fp);
+    pclose(fp);
+
+    std::string const CLANG_FORMAT_OPTIONS =
+            "-style='{"
+            "BasedOnStyle: Google, "
+            "IndentWidth: 4, "
+            "MaxEmptyLinesToKeep: 2"
+            "}'";
+
+    fp = popen(("clang-format " + CLANG_FORMAT_OPTIONS + "< " + TMP_FILENAME).c_str(), "r");
+
+    if (!fp) {
+        std::call_once(mClangWarningFlag, []() {
+            utils::slog.w << "[matdbg] unable to run clang-format to format shader file. "
+                          << "Please make sure it's installed.";
+        });
+        return original;
+    }
+
+    char output[1024];
+    std::stringstream outStream;
+    while (fgets(output, 1024, fp) != NULL) {
+        outStream << output;
+    }
+
+    int status = pclose(fp);
+    if (WEXITSTATUS(status)) {
+        utils::slog.w << "[matdbg] clang-format failed with code=" << WEXITSTATUS(status)
+                      << utils::io::endl;
+    }
+    return outStream.str();
+}
+#else
+std::string SourceFormatter::format(char const* source) {
+    std::call_once(mClangWarningFlag, []() {    
+        utils::slog.w <<"[matdbg]: source formatting is not available on this platform" <<
+                utils::io::endl;
+    });
+    return "";
+}
+#endif
+
+} // filament::matdbg
diff --git a/libs/matdbg/src/SourceFormatter.h b/libs/matdbg/src/SourceFormatter.h
new file mode 100644
index 000000000000..5793474d7168
--- /dev/null
+++ b/libs/matdbg/src/SourceFormatter.h
@@ -0,0 +1,37 @@
+/*
+ * 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.
+ */
+
+#ifndef MATDBG_SOURCE_FORMATTER_H
+#define MATDBG_SOURCE_FORMATTER_H
+
+#include <mutex>
+
+namespace filament::matdbg {
+
+class SourceFormatter {
+public:
+    SourceFormatter() = default;
+    ~SourceFormatter() = default;
+    std::string format(char const* source);
+
+private:
+
+    std::once_flag mClangWarningFlag;
+};
+
+} // filament::matdbg
+
+#endif // MATDBG_SOURCE_FORMATTER_H
diff --git a/libs/matdbg/web/app.js b/libs/matdbg/web/app.js
index 4a7c7df4e444..325d47487fd6 100644
--- a/libs/matdbg/web/app.js
+++ b/libs/matdbg/web/app.js
@@ -452,6 +452,7 @@ class AdvancedOptions extends LitElement {
     static get properties() {
         return {
             currentBackend: {type: String, attribute: 'current-backend'},
+            hideInactiveVariants: {type: Boolean, attribute: 'hide-inactive-variants'},
             availableBackends: {type: Array, state: true},
         };
     }
@@ -470,6 +471,9 @@ class AdvancedOptions extends LitElement {
                 justify-content: center;
                 align-items: flex-start;
             }
+            .borderless {
+                border: 1px solid rgba(0,0,0,0);
+            }
             label {
                 display: flex;
                 flex-direction: row;
@@ -486,6 +490,35 @@ class AdvancedOptions extends LitElement {
             .option-heading {
                 margin-bottom: 5px;
             }
+
+            /* Below is a custom checkbox */
+            input[type="checkbox"] {
+                -webkit-appearance: none;
+                appearance: none;
+                background-color: var(--form-background);
+                margin-right: 5px;
+                font: inherit;
+                width: 1.15em;
+                height: 1.15em;
+                border: 0.15em solid ${unsafeCSS(UNSELECTED_COLOR)};
+                border-radius: 0.15em;
+                display: grid;
+                place-content: center;
+            }
+            input[type="checkbox"]::before {
+                content: "";
+                width: 0.65em;
+                height: 0.65em;
+                clip-path: polygon(14% 44%, 0 65%, 50% 100%, 100% 16%, 80% 0%, 43% 62%);
+                transform: scale(0);
+                transform-origin: bottom left;
+                box-shadow: inset 1em 1em var(--form-control-color);
+                /* Windows High Contrast Mode */
+                background-color: ${unsafeCSS(FOREGROUND_COLOR)};
+            }
+            input[type="checkbox"]:checked::before {
+                transform: scale(1);
+            }
         `;
     }
 
@@ -536,6 +569,25 @@ class AdvancedOptions extends LitElement {
         `;
     }
 
+    _hideInactiveVariantsOption() {
+        const onChange = (ev) => {
+            this.dispatchEvent(
+                new CustomEvent(
+                    'option-hide-inactive-variants',
+                    {detail: null, bubbles: true, composed: true}));
+        }
+        return html`
+            <div class="option borderless">
+                <!--<div class="option-heading">Current Backend</div>-->
+                <form action="" id="hide-inactive-variants-form">
+                    <input type="checkbox" name="InactiveVariants"
+                       ?checked=${this.hideInactiveVariants} @change=${onChange}/>
+                    Hide Inactive Variants
+                </form>
+            </div>
+        `;
+    }
+
     constructor() {
         super();
         this.availableBackends = [];
@@ -544,6 +596,7 @@ class AdvancedOptions extends LitElement {
     render() {
         return html`
             <menu-section title="Advanced Options">
+                ${this._hideInactiveVariantsOption() ?? nothing}
                 ${this._backendOption() ?? nothing}
             </menu-section>
         `;
@@ -613,11 +666,11 @@ class MaterialSidePanel extends LitElement {
             currentShaderIndex: {type: Number, attribute: 'current-shader-index'},
             currentBackend: {type: String, attribute: 'current-backend'},
             currentLanguage: {type: String, attribute: 'current-language'},
+            hideInactiveVariants: {type: Boolean, attribute: 'hide-inactive-variants'},
 
             database: {type: Object, state: true},
             materials: {type: Array, state: true},
             activeShaders: {type: Object, state: true},
-
             variants: {type: Array, state: true},
         }
     }
@@ -662,8 +715,8 @@ class MaterialSidePanel extends LitElement {
                 let name = material.name || kUntitledPlaceholder;
                 if (name in duplicatedLabels) {
                     const index = duplicatedLabels[name];
-                    name = `${name} (${index})`;
                     duplicatedLabels[name] = index + 1;
+                    name = `${name} (${index})`;
                 }
                 return {
                     matid: matid,
@@ -747,6 +800,7 @@ class MaterialSidePanel extends LitElement {
                     if (b.active && !a.active) return 1;
                     return 0;
                 })
+                .filter((variant) => (!this.hideInactiveVariants || variant.shader.active))
                 .map((variant) => {
                     let divClass = 'material_variant_language';
                     const shaderIndex = +variant.shader.index;
@@ -778,7 +832,13 @@ class MaterialSidePanel extends LitElement {
 
     render() {
         const sections = (title, domain) => {
-            const mats = this.materials.filter((m) => m.domain == domain).map((mat) => {
+            const mats = this.materials
+                             .filter((m) => m.domain == domain)
+                             .filter((mat) => {
+                                 const material = this.database[mat.matid];
+                                 return !this.hideInactiveVariants || material.active;
+                             })
+                             .map((mat) => {
                 const material = this.database[mat.matid];
                 const onClick = this._handleMaterialClick.bind(this, mat.matid);
                 let divClass = 'material_variant_language';
@@ -806,15 +866,13 @@ class MaterialSidePanel extends LitElement {
             }
             return null;
         };
-        let advancedOptions = null;
-        // Currently we only have one advanced option and it's only for when we're in matinfo
-        if (_isMatInfoMode(this.database)) {
-            advancedOptions =
-                (() => html`
-                    <advanced-options id="advanced-options"
-                             current-backend=${this.currentBackend}></advanced-options>
-                `)();
-        }
+        const advancedOptions =
+            (() => html`
+                <advanced-options id="advanced-options"
+                         current-backend=${this.currentBackend}
+                         ?hide-inactive-variants=${this.hideInactiveVariants}
+                ></advanced-options>
+            `)();
 
         return html`
             <style>${this.dynamicStyle()}</style>
@@ -874,6 +932,12 @@ class MatdbgViewer extends LitElement {
 
         let materials = await fetchMaterials();
         this.database = materials;
+
+        // This is the user preferences stored in localStorage
+        let hideInactiveVariantsVal = localStorage.getItem('option-hide-inactive-variants');
+        if (hideInactiveVariantsVal != null) {
+            this.hideInactiveVariants = hideInactiveVariantsVal == 'true';
+        }
     }
 
     _getShader() {
@@ -907,6 +971,7 @@ class MatdbgViewer extends LitElement {
         this.currentMaterial = null;
         this.currentLanguage = null;
         this.currentBackend = null;
+        this.hideInactiveVariants = false;
         this.init();
 
         this.addEventListener('select-material',
@@ -957,6 +1022,12 @@ class MatdbgViewer extends LitElement {
             }
         );
 
+        this.addEventListener('option-hide-inactive-variants',
+            (ev) => {
+                this.hideInactiveVariants = !this.hideInactiveVariants;
+                localStorage.setItem('option-hide-inactive-variants', "" + this.hideInactiveVariants);
+            }
+        );
         addEventListener('resize', this._onResize.bind(this));
     }
 
@@ -972,6 +1043,8 @@ class MatdbgViewer extends LitElement {
             currentBackend: {type: String, state: true},
             codeViewerExpectedWidth: {type: Number, state: true},
             codeViewerExpectedHeight: {type: Number, state: true},
+
+            hideInactiveVariants: {type: Boolean, state: true},
         }
     }
 
@@ -1085,7 +1158,8 @@ class MatdbgViewer extends LitElement {
                      current-language="${this.currentLanguage}"
                      current-shader-index="${this.currentShaderIndex}"
                      current-material="${this.currentMaterial}"
-                     current-backend="${this.currentBackend}" >
+                     current-backend="${this.currentBackend}"
+                     ?hide-inactive-variants="${this.hideInactiveVariants}" >
             </material-sidepanel>
             <code-viewer id="code-viewer"
                  ?active=${shader && shader.active}
diff --git a/samples/gltf_viewer.cpp b/samples/gltf_viewer.cpp
index 47d6055dd3a9..bdde92b0f667 100644
--- a/samples/gltf_viewer.cpp
+++ b/samples/gltf_viewer.cpp
@@ -158,7 +158,7 @@ static void printUsage(char* name) {
         "       Specify the backend API: "
 
 // Matches logic in filament/backend/src/PlatformFactory.cpp for Backend::DEFAULT
-#if defined(IOS) || defined(__APPLE__)
+#if defined(FILAMENT_IOS) || defined(__APPLE__)
         "opengl, vulkan, or metal (default)"
 #elif defined(FILAMENT_DRIVER_SUPPORTS_VULKAN)
         "opengl, vulkan (default), or metal"
diff --git a/third_party/clang/iOS.cmake b/third_party/clang/iOS.cmake
index e9ea75e7a4ad..a935c08f6639 100644
--- a/third_party/clang/iOS.cmake
+++ b/third_party/clang/iOS.cmake
@@ -13,7 +13,7 @@ set(CMAKE_OSX_ARCHITECTURES ${IOS_ARCH} CACHE STRING "Build architecture for iOS
 # Necessary for correct install location
 set(DIST_ARCH ${IOS_ARCH})
 
-add_definitions(-DIOS)
+add_definitions(-DFILAMENT_IOS)
 
 set(IOS_MIN_TARGET "11.0")
 
diff --git a/web/filament-js/jsbindings.cpp b/web/filament-js/jsbindings.cpp
index c45c50b35b1f..1ca1b97c93f1 100644
--- a/web/filament-js/jsbindings.cpp
+++ b/web/filament-js/jsbindings.cpp
@@ -1489,6 +1489,8 @@ class_<TexBuilder>("Texture$Builder")
         return &builder->sampler(target); })
     .BUILDER_FUNCTION("format", TexBuilder, (TexBuilder* builder, Texture::InternalFormat fmt), {
         return &builder->format(fmt); })
+    .BUILDER_FUNCTION("external", TexBuilder, (TexBuilder* builder), {
+        return &builder->external(); })
 
     // This takes a bitfield that can be composed by or'ing constants.
     // - JS clients should use the value member, as in: "Texture$Usage.SAMPLEABLE.value".
diff --git a/web/filament-js/package.json b/web/filament-js/package.json
index e78ccf5f932d..3a8340976cb8 100644
--- a/web/filament-js/package.json
+++ b/web/filament-js/package.json
@@ -1,6 +1,6 @@
 {
   "name": "filament",
-  "version": "1.56.5",
+  "version": "1.56.6",
   "description": "Real-time physically based rendering engine",
   "main": "filament.js",
   "module": "filament.js",