vk: update vulkan memory allocator lib

2025-06-12 15:23:38 -07:00
161 changed files with 23395 additions and 25219 deletions
@@ -54,6 +54,7 @@ jobs:
  build-android:
    name: build-android
    runs-on: 'ubuntu-24.04-16core'
+
    steps:
      - uses: actions/checkout@v4.1.6
        with:
@@ -72,6 +73,7 @@ jobs:
  build-ios:
    name: build-iOS
    runs-on: macos-14-xlarge
+
    steps:
      - uses: actions/checkout@v4.1.6
        with:
@@ -87,6 +89,7 @@ jobs:
  build-web:
    name: build-web
    runs-on: 'ubuntu-24.04-16core'
+
    steps:
      - uses: actions/checkout@v4.1.6
        with:
@@ -104,12 +107,11 @@ jobs:
      - uses: actions/checkout@v4.1.6
        with:
          fetch-depth: 0
-      - id: get_commit_msg
-        uses: ./.github/actions/get-commit-msg
      - name: Check for manual edits to /docs
        run: |
-          COMMIT_ID=$(echo "${{ steps.get_commit_msg.outputs.msg }}" | head -n 1 | sed "s/commit //g")
-          bash docs_src/build/presubmit_check.sh ${COMMIT_ID}
+          echo "${{ github.event.pull_request.head.sha }} -- ${{ github.event.pull_request.head.sha }}"
+          # disable for now
+          # bash docs_src/build/presubmit_check.sh ${{ github.event.pull_request.head.sha }}

  test-renderdiff:
    name: test-renderdiff
@@ -136,7 +138,7 @@ jobs:
      - uses: actions/upload-artifact@v4
        with:
          name: presubmit-renderdiff-result
-          path: ./out/renderdiff
+          path: ./out/renderdiff_tests

  validate-wgsl-webgpu:
    name: validate-wgsl-webgpu
@@ -31,7 +31,7 @@ repositories {
 }

 dependencies {
-    implementation 'com.google.android.filament:filament-android:1.62.0'
+    implementation 'com.google.android.filament:filament-android:1.61.1'
 }
 ```

@@ -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', '~> 1.62.0'
+pod 'Filament', '~> 1.61.1'
 ```

 ## Documentation
@@ -7,18 +7,11 @@ 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).

-## v1.62.1
-
- Add new shader define `VARIANT_DEPTH`, defined when a material is compiled for depth variants
-  (e.g., shadows) [**Requires recompiling materials**]
-
 ## v1.62.0

- Add new `unfilterable` field to Filament Material's `sampler` [⚠️ **New Material Version**]
-
-## v1.61.2
-
 - samples: samples now have a CLI to select backend api
+- materials: sampler now export their type in the material binary [⚠️ **New Material Version**]
+- materials: new mutable specialization constants feature. See the [materials documentation](https://google.github.io/filament/Materials.html) for details. [⚠️ **New Material Version**]

 ## v1.61.1

@@ -556,8 +556,7 @@ extern "C" JNIEXPORT void JNICALL Java_com_google_android_filament_Engine_nSetBu
        jlong resourceAllocatorCacheSizeMB, jlong resourceAllocatorCacheMaxAge,
        jboolean disableHandleUseAfterFreeCheck,
        jint preferredShaderLanguage,
-        jboolean forceGLES2Context, jboolean assertNativeWindowIsValid,
-        jint gpuContextPriority) {
+        jboolean forceGLES2Context, jboolean assertNativeWindowIsValid) {
    Engine::Builder* builder = (Engine::Builder*) nativeBuilder;
    Engine::Config config = {
            .commandBufferSizeMB = (uint32_t) commandBufferSizeMB,
@@ -575,7 +574,6 @@ extern "C" JNIEXPORT void JNICALL Java_com_google_android_filament_Engine_nSetBu
            .preferredShaderLanguage = (Engine::Config::ShaderLanguage) preferredShaderLanguage,
            .forceGLES2Context = (bool) forceGLES2Context,
            .assertNativeWindowIsValid = (bool) assertNativeWindowIsValid,
-            .gpuContextPriority = (Engine::GpuContextPriority) gpuContextPriority,
    };
    builder->config(&config);
 }
@@ -60,6 +60,14 @@ static void setParameter(JNIEnv* env, jlong nativeMaterialInstance, jstring name
    env->ReleaseStringUTFChars(name_, name);
 }

+template<typename T>
+static void setConstant(JNIEnv* env, jlong nativeMaterialInstance, jstring name_, T v) {
+    MaterialInstance* instance = (MaterialInstance*) nativeMaterialInstance;
+    const char *name = env->GetStringUTFChars(name_, 0);
+    instance->setConstant(name, v);
+    env->ReleaseStringUTFChars(name_, name);
+}
+
 extern "C"
 JNIEXPORT void JNICALL
 Java_com_google_android_filament_MaterialInstance_nSetParameterBool(JNIEnv *env, jclass,
@@ -264,6 +272,13 @@ Java_com_google_android_filament_MaterialInstance_nSetParameterTexture(
    env->ReleaseStringUTFChars(name_, name);
 }

+extern "C"
+JNIEXPORT void JNICALL
+Java_com_google_android_filament_MaterialInstance_nSetConstantBool(JNIEnv *env, jclass,
+        jlong nativeMaterialInstance, jstring name_, jboolean x) {
+    setConstant(env, nativeMaterialInstance, name_, bool(x));
+}
+
 extern "C"
 JNIEXPORT void JNICALL
 Java_com_google_android_filament_MaterialInstance_nSetScissor(
@@ -175,36 +175,6 @@ public class Engine {
        MULTIVIEW,
    };

-    /**
-     * This controls the priority level for GPU work scheduling, which helps prioritize the
-     * submitted GPU work and enables preemption.
-     */
-    public enum GpuContextPriority {
-        /**
-         * Backend default GPU context priority (typically MEDIUM)
-         */
-        DEFAULT,
-        /**
-         * For non-interactive, deferrable workloads. This should not interfere with standard
-         * applications.
-         */
-        LOW,
-        /**
-         * The default priority level for standard applications.
-         */
-        MEDIUM,
-        /**
-         * For high-priority, latency-sensitive workloads that are more important than standard
-         * applications.
-         */
-        HIGH,
-        /**
-         * The highest priority, intended for system-critical, real-time applications where missing
-         * deadlines is unacceptable (e.g., VR/AR compositors or other system-critical tasks).
-         */
-        REALTIME,
-    };
-
    /**
     * Constructs <code>Engine</code> objects using a builder pattern.
     */
@@ -263,8 +233,7 @@ public class Engine {
                    config.resourceAllocatorCacheSizeMB, config.resourceAllocatorCacheMaxAge,
                    config.disableHandleUseAfterFreeCheck,
                    config.preferredShaderLanguage.ordinal(),
-                    config.forceGLES2Context, config.assertNativeWindowIsValid,
-                    config.gpuContextPriority.ordinal());
+                    config.forceGLES2Context, config.assertNativeWindowIsValid);
            return this;
        }

@@ -520,11 +489,6 @@ public class Engine {
         * @Deprecated use "backend.opengl.assert_native_window_is_valid" feature flag instead
         */
        public boolean assertNativeWindowIsValid = false;
-
-        /**
-         * GPU context priority level. Controls GPU work scheduling and preemption.
-         */
-        public GpuContextPriority gpuContextPriority = GpuContextPriority.DEFAULT;
    }

    private Engine(long nativeEngine, Config config) {
@@ -1528,8 +1492,7 @@ public class Engine {
            long resourceAllocatorCacheSizeMB, long resourceAllocatorCacheMaxAge,
            boolean disableHandleUseAfterFreeCheck,
            int preferredShaderLanguage,
-            boolean forceGLES2Context, boolean assertNativeWindowIsValid,
-            int gpuContextPriority);
+            boolean forceGLES2Context, boolean assertNativeWindowIsValid);
    private static native void nSetBuilderFeatureLevel(long nativeBuilder, int ordinal);
    private static native void nSetBuilderSharedContext(long nativeBuilder, long sharedContext);
    private static native void nSetBuilderPaused(long nativeBuilder, boolean paused);
@@ -402,6 +402,16 @@ public class MaterialInstance {
        nSetParameterFloat4(getNativeObject(), name, color[0], color[1], color[2], color[3]);
    }

+    /**
+     * Sets the value of a bool constant.
+     *
+     * @param name the name of the material constant
+     * @param x    the value of the material constant
+     */
+    public void setConstant(@NonNull String name, boolean x) {
+        nSetConstantBool(getNativeObject(), name, x);
+    }
+
    /**
     * Set-up a custom scissor rectangle; by default it is disabled.
     *
@@ -921,6 +931,9 @@ public class MaterialInstance {
            @NonNull String name, int element, @NonNull @Size(min = 1) float[] v,
            @IntRange(from = 0) int offset, @IntRange(from = 1) int count);

+    private static native void nSetConstantBool(long nativeMaterialInstance,
+            @NonNull String name, boolean x);
+
    private static native void nSetParameterTexture(long nativeMaterialInstance,
            @NonNull String name, long nativeTexture, long sampler);

@@ -1,5 +1,5 @@
 GROUP=com.google.android.filament
-VERSION_NAME=1.62.0
+VERSION_NAME=1.61.1

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

@@ -1,7 +1,6 @@
+#Wed Nov 17 10:40:18 PST 2021
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 distributionUrl=https\://services.gradle.org/distributions/gradle-8.8-bin.zip
-networkTimeout=10000
-validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
@@ -1,7 +1,7 @@
-#!/bin/sh
+#!/usr/bin/env sh

 #
-# Copyright © 2015-2021 the original authors.
+# Copyright 2015 the original author or authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -17,99 +17,67 @@
 #

 ##############################################################################
-#
-#   Gradle start up script for POSIX generated by Gradle.
-#
-#   Important for running:
-#
-#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
-#       noncompliant, but you have some other compliant shell such as ksh or
-#       bash, then to run this script, type that shell name before the whole
-#       command line, like:
-#
-#           ksh Gradle
-#
-#       Busybox and similar reduced shells will NOT work, because this script
-#       requires all of these POSIX shell features:
-#         * functions;
-#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
-#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
-#         * compound commands having a testable exit status, especially «case»;
-#         * various built-in commands including «command», «set», and «ulimit».
-#
-#   Important for patching:
-#
-#   (2) This script targets any POSIX shell, so it avoids extensions provided
-#       by Bash, Ksh, etc; in particular arrays are avoided.
-#
-#       The "traditional" practice of packing multiple parameters into a
-#       space-separated string is a well documented source of bugs and security
-#       problems, so this is (mostly) avoided, by progressively accumulating
-#       options in "$@", and eventually passing that to Java.
-#
-#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
-#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
-#       see the in-line comments for details.
-#
-#       There are tweaks for specific operating systems such as AIX, CygWin,
-#       Darwin, MinGW, and NonStop.
-#
-#   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
-#       within the Gradle project.
-#
-#       You can find Gradle at https://github.com/gradle/gradle/.
-#
+##
+##  Gradle start up script for UN*X
+##
 ##############################################################################

 # Attempt to set APP_HOME
-
 # Resolve links: $0 may be a link
-app_path=$0
-
-# Need this for daisy-chained symlinks.
-while
-    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
-    [ -h "$app_path" ]
-do
-    ls=$( ls -ld "$app_path" )
-    link=${ls#*' -> '}
-    case $link in             #(
-      /*)   app_path=$link ;; #(
-      *)    app_path=$APP_HOME$link ;;
-    esac
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
 done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null

-# This is normally unused
-# shellcheck disable=SC2034
-APP_BASE_NAME=${0##*/}
-# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
-APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'

 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD=maximum
+MAX_FD="maximum"

 warn () {
    echo "$*"
-} >&2
+}

 die () {
    echo
    echo "$*"
    echo
    exit 1
-} >&2
+}

 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "$( uname )" in                #(
-  CYGWIN* )         cygwin=true  ;; #(
-  Darwin* )         darwin=true  ;; #(
-  MSYS* | MINGW* )  msys=true    ;; #(
-  NONSTOP* )        nonstop=true ;;
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
 esac

 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
@@ -119,9 +87,9 @@ CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 if [ -n "$JAVA_HOME" ] ; then
    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
        # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD=$JAVA_HOME/jre/sh/java
+        JAVACMD="$JAVA_HOME/jre/sh/java"
    else
-        JAVACMD=$JAVA_HOME/bin/java
+        JAVACMD="$JAVA_HOME/bin/java"
    fi
    if [ ! -x "$JAVACMD" ] ; then
        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -130,120 +98,88 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
    fi
 else
-    JAVACMD=java
-    if ! command -v java >/dev/null 2>&1
-    then
-        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.

 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
-    fi
 fi

 # Increase the maximum file descriptors if we can.
-if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
-    case $MAX_FD in #(
-      max*)
-        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC2039,SC3045
-        MAX_FD=$( ulimit -H -n ) ||
-            warn "Could not query maximum file descriptor limit"
-    esac
-    case $MAX_FD in  #(
-      '' | soft) :;; #(
-      *)
-        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC2039,SC3045
-        ulimit -n "$MAX_FD" ||
-            warn "Could not set maximum file descriptor limit to $MAX_FD"
-    esac
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
 fi

-# Collect all arguments for the java command, stacking in reverse order:
-#   * args from the command line
-#   * the main class name
-#   * -classpath
-#   * -D...appname settings
-#   * --module-path (only if needed)
-#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi

 # For Cygwin or MSYS, switch paths to Windows format before running java
-if "$cygwin" || "$msys" ; then
-    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`

-    JAVACMD=$( cygpath --unix "$JAVACMD" )
+    JAVACMD=`cygpath --unix "$JAVACMD"`

-    # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    for arg do
-        if
-            case $arg in                                #(
-              -*)   false ;;                            # don't mess with options #(
-              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
-                    [ -e "$t" ] ;;                      #(
-              *)    false ;;
-            esac
-        then
-            arg=$( cygpath --path --ignore --mixed "$arg" )
-        fi
-        # Roll the args list around exactly as many times as the number of
-        # args, so each arg winds up back in the position where it started, but
-        # possibly modified.
-        #
-        # NB: a `for` loop captures its iteration list before it begins, so
-        # changing the positional parameters here affects neither the number of
-        # iterations, nor the values presented in `arg`.
-        shift                   # remove old arg
-        set -- "$@" "$arg"      # push replacement arg
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
 fi

+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`

-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
-
-# Collect all arguments for the java command:
-#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
-#     and any embedded shellness will be escaped.
-#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
-#     treated as '${Hostname}' itself on the command line.
-
-set -- \
-        "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
-        "$@"
-
-# Stop when "xargs" is not available.
-if ! command -v xargs >/dev/null 2>&1
-then
-    die "xargs is not available"
-fi
-
-# Use "xargs" to parse quoted args.
-#
-# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
-#
-# In Bash we could simply go:
-#
-#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
-#   set -- "${ARGS[@]}" "$@"
-#
-# but POSIX shell has neither arrays nor command substitution, so instead we
-# post-process each arg (as a line of input to sed) to backslash-escape any
-# character that might be a shell metacharacter, then use eval to reverse
-# that process (while maintaining the separation between arguments), and wrap
-# the whole thing up as a single "set" statement.
-#
-# This will of course break if any of these variables contains a newline or
-# an unmatched quote.
-#
-
-eval "set -- $(
-        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
-        xargs -n1 |
-        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
-        tr '\n' ' '
-    )" '"$@"'
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"

 exec "$JAVACMD" "$@"
@@ -14,7 +14,7 @@
@rem limitations under the License.
@rem

-@if "%DEBUG%"=="" @echo off
+@if "%DEBUG%" == "" @echo off
@rem ##########################################################################
@rem
@rem  Gradle startup script for Windows
@@ -25,8 +25,7 @@
 if "%OS%"=="Windows_NT" setlocal

 set DIRNAME=%~dp0
-if "%DIRNAME%"=="" set DIRNAME=.
-@rem This is normally unused
+if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%

@@ -41,13 +40,13 @@ if defined JAVA_HOME goto findJavaFromJavaHome

 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if %ERRORLEVEL% equ 0 goto execute
+if "%ERRORLEVEL%" == "0" goto execute

-echo. 1>&2
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
-echo. 1>&2
-echo Please set the JAVA_HOME variable in your environment to match the 1>&2
-echo location of your Java installation. 1>&2
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.

 goto fail

@@ -57,11 +56,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe

 if exist "%JAVA_EXE%" goto execute

-echo. 1>&2
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
-echo. 1>&2
-echo Please set the JAVA_HOME variable in your environment to match the 1>&2
-echo location of your Java installation. 1>&2
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.

 goto fail

@@ -76,15 +75,13 @@ set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar

 :end
@rem End local scope for the variables with windows NT shell
-if %ERRORLEVEL% equ 0 goto mainEnd
+if "%ERRORLEVEL%"=="0" goto mainEnd

 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-set EXIT_CODE=%ERRORLEVEL%
-if %EXIT_CODE% equ 0 set EXIT_CODE=1
-if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
-exit /b %EXIT_CODE%
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1

 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
@@ -18,7 +18,6 @@ package com.google.android.filament.gltf

 import android.annotation.SuppressLint
 import android.app.Activity
-import android.content.Intent
 import android.os.Bundle
 import android.util.Log
 import android.view.*
@@ -51,7 +50,6 @@ class MainActivity : Activity() {
        // Load the library for the utility layer, which in turn loads gltfio and the Filament core.
        init { Utils.init() }
        private const val TAG = "gltf-viewer"
-        private const val STATIC_MODEL_TAG = "use-static-model"
    }

    private lateinit var surfaceView: SurfaceView
@@ -71,7 +69,6 @@ class MainActivity : Activity() {
    private var loadStartTime = 0L
    private var loadStartFence: Fence? = null
    private val viewerContent = AutomationEngine.ViewerContent()
-    private var useStaticModel = false

    @SuppressLint("ClickableViewAccessibility")
    override fun onCreate(savedInstanceState: Bundle?) {
@@ -86,12 +83,6 @@ class MainActivity : Activity() {
        doubleTapDetector = GestureDetector(applicationContext, doubleTapListener)
        singleTapDetector = GestureDetector(applicationContext, singleTapListener)

-        val intent: Intent = intent
-        val bundle: Bundle? = intent.extras
-        bundle?.let {
-            useStaticModel = it.getBoolean(STATIC_MODEL_TAG, false)
-        }
-
        modelViewer = ModelViewer(surfaceView)
        viewerContent.view = modelViewer.view
        viewerContent.sunlight = modelViewer.light
@@ -150,16 +141,7 @@ class MainActivity : Activity() {
    }

    private fun createDefaultRenderables() {
-        // Sometimes it's useful to set to the default model to something static. You can enable
-        // the static model by launching the app from adb, as in
-        // `adb shell am start -n com.google.android.filament.gltf/.MainActivity --ez "use-static-model" true`
-        val modelPath = if (useStaticModel) {
-            "models/helmet.glb"
-        } else {
-            "models/scene.gltf"
-        }
-
-        val buffer = assets.open(modelPath).use { input ->
+        val buffer = assets.open("models/scene.gltf").use { input ->
            val bytes = ByteArray(input.available())
            input.read(bytes)
            ByteBuffer.wrap(bytes)
@@ -204,10 +204,9 @@
      "license": "Apache-2.0"
    },
    "node_modules/brace-expansion": {
-      "version": "1.1.12",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.12.tgz",
-      "integrity": "sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg==",
-      "license": "MIT",
+      "version": "1.1.11",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
+      "integrity": "sha512-iCuPHDFgrHX7H2vEI/5xpz07zSHB00TpugqhmYtVmMO6518mCuRMoOYFldEBl0g187ufozdaHgWKcYFb61qGiA==",
      "dependencies": {
        "balanced-match": "^1.0.0",
        "concat-map": "0.0.1"
@@ -410,9 +409,9 @@
      "integrity": "sha512-Nik3Sc0ncrMK4UUdXQmAnRtzmNQTAAXmXIopizwZ1W1t8QmfJj+zL4OA2I7XPTPW5z5TDqv4hRo/JzouDJnX3A=="
    },
    "brace-expansion": {
-      "version": "1.1.12",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.12.tgz",
-      "integrity": "sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg==",
+      "version": "1.1.11",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
+      "integrity": "sha512-iCuPHDFgrHX7H2vEI/5xpz07zSHB00TpugqhmYtVmMO6518mCuRMoOYFldEBl0g187ufozdaHgWKcYFb61qGiA==",
      "requires": {
        "balanced-match": "^1.0.0",
        "concat-map": "0.0.1"
@@ -1027,11 +1027,8 @@ samplerCubemap         | Cubemap texture
 [Table [materialParamsTypes]: Material parameter types]

 Samplers
-:     Sampler types can have the following fields:
-       - `format` : which can be either `int` or `float` (defaults to `float`).
-       - `multisample` : a boolean to indicate whether the sampler is meant for multisampling (defaults to `false`)
-       - `unfilterable` : a boolean to indicate whether the sampling is not filtered (defaults to `false`)
-
+:     Sampler types can also specify a `format` which can be either `int` or `float` (defaults to
+      `float`).

 Arrays
 :     A parameter can define an array of values by appending `[size]` after the type name, where
@@ -30,6 +30,11 @@ from utils import execute, ArgParseImpl
 CUR_DIR = os.path.dirname(os.path.abspath(__file__))
 ROOT_DIR = os.path.join(CUR_DIR, '../../')

+def get_last_commit_hash():
+  res, ret = execute('git rev-parse HEAD', cwd=ROOT_DIR)
+  assert res == 0, 'Failed to get the last commit hash'
+  return ret.strip()
+
 def get_edited_files(commit_hash):
  INSERT = '#####?????'
  res, ret = execute(f'git show --name-only --pretty=%b{INSERT} {commit_hash}')
@@ -39,13 +39,13 @@ function download_mdbook() {
    fi

    local CHECK_UNAME="
-import sys
-parts=[a.lower() for a in sys.stdin.read().strip().split(' ')]
+import sys;
+parts=[a.lower() for a in sys.stdin.read().strip().split(' ')];
 def get_type():
  if 'darwin' in parts:
    if 'x86_64' in parts:
      return ${DARWIN_X86}
-    elif 'aarch' in parts or 'arm64' in parts:
+    elif 'aarch' in parts:
      return ${DARWIN_ARM}
  elif 'linux' in parts:
    if 'x86_64' in parts:
@@ -63,12 +63,11 @@ print(get_type())
            echo "*** Need to install Rust ***"
            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
        fi
-        source "${HOME}/.cargo/env"
        if ! (command -v cargo >/dev/null 2>&1); then
-            echo "*** Still cannot find cargo ***"
+            echo "*** Still cannot find `cargo` ***"
            exit 1
        fi
-        cargo install --force mdbook
+        cargo install mdbook
    else
        # Download prebuilts from github
        mkdir -p ${HOME}/.cargo/bin
@@ -13,7 +13,7 @@ This document is part of the [Filament project](https://github.com/google/filame
 ## Authors

 - [Romain Guy](https://github.com/romainguy), [@romainguy](https://twitter.com/romainguy)
- [Mathias Agopian](https://github.com/pixelflinger), [@pixelflinger](https://bsky.app/profile/pixelflinger.bsky.social)
+- [Mathias Agopian](https://github.com/pixelflinger), [@darthmoosious](https://twitter.com/darthmoosious)

 # Overview

@@ -78,27 +78,26 @@ in table [standardProperties].
        Property        |      Definition
 -----------------------:|:---------------------
 **baseColor**           | Diffuse albedo for non-metallic surfaces, and specular color for metallic surfaces
-**roughness**           | Perceived smoothness (1.0) or roughness (0.0) of a surface. Smooth surfaces exhibit sharp reflections
 **metallic**            | Whether a surface appears to be dielectric (0.0) or conductor (1.0). Often used as a binary value (0 or 1)
+**roughness**           | Perceived smoothness (1.0) or roughness (0.0) of a surface. Smooth surfaces exhibit sharp reflections
 **reflectance**         | Fresnel reflectance at normal incidence for dielectric surfaces. This directly controls the strength of the reflections
-**ambientOcclusion**    | Defines how much of the ambient light is accessible to a surface point. It is a per-pixel shadowing factor between 0.0 and 1.0
-**clearCoat**           | Strength of the clear coat layer
-**clearCoatRoughness**  | Perceived smoothness or roughness of the clear coat layer
-**clearCoatNormal**     | A detail normal used to perturb the clear coat layer using _bump mapping_ (_normal mapping_)
-**anisotropy**          | Amount of anisotropy in either the tangent or bitangent direction
-**anisotropyDirection** | Local surface direction in tangent space
-**thickness**           | Thickness of the solid volume of refractive objects
 **sheenColor**          | Strength of the sheen layer
 **sheenRoughness**      | Perceived smoothness or roughness of the sheen layer
-**emissive**            | Additional diffuse albedo to simulate emissive surfaces (such as neons, etc.) This property is mostly useful in an HDR pipeline with a bloom pass
+**clearCoat**           | Strength of the clear coat layer
+**clearCoatRoughness**  | Perceived smoothness or roughness of the clear coat layer
+**anisotropy**          | Amount of anisotropy in either the tangent or bitangent direction
+**anisotropyDirection** | Local surface direction in tangent space
+**ambientOcclusion**    | Defines how much of the ambient light is accessible to a surface point. It is a per-pixel shadowing factor between 0.0 and 1.0
 **normal**              | A detail normal used to perturb the surface using _bump mapping_ (_normal mapping_)
-**postLightingColor**   | Additional color that can be blended with the result of the lighting computations. See `postLightingBlending`
-**absorption**          | Absorption factor for refractive objects
-**transmission**        | Defines how much of the diffuse light of a dielectric is transmitted through the object, in other words this defines how transparent an object is
-**ior**                 | Index of refraction, either for refractive objects or as an alternative to reflectance
-**microThickness**      | Thickness of the thin layer of refractive objects
 **bentNormal**          | A normal pointing in the average unoccluded direction. Can be used to improve indirect lighting quality
-**shadowStrength**      | Strength factor between 0 and 1 for all shadows received by this material
+**clearCoatNormal**     | A detail normal used to perturb the clear coat layer using _bump mapping_ (_normal mapping_)
+**emissive**            | Additional diffuse albedo to simulate emissive surfaces (such as neons, etc.) This property is mostly useful in an HDR pipeline with a bloom pass
+**postLightingColor**   | Additional color that can be blended with the result of the lighting computations. See `postLightingBlending`
+**ior**                 | Index of refraction, either for refractive objects or as an alternative to reflectance
+**transmission**        | Defines how much of the diffuse light of a dielectric is transmitted through the object, in other words this defines how transparent an object is
+**absorption**          | Absorption factor for refractive objects
+**microThickness**      | Thickness of the thin layer of refractive objects
+**thickness**           | Thickness of the solid volume of refractive objects
 [Table [standardProperties]: Properties of the standard model]

 The type and range of each property is described in table [standardPropertiesTypes].
@@ -212,7 +211,7 @@ when using textures.
 This property can dramatically change the appearance of a surface. Non-metallic surfaces have
 chromatic diffuse reflection and achromatic specular reflection (reflected light does not change
 color). Metallic surfaces do not have any diffuse reflection and chromatic specular reflection
-(reflected light takes on the color of the surfaced as defined by `baseColor`). 
+(reflected light takes on the color of the surfaced as defined by `baseColor`).

 The effect of `metallic` is shown in figure [metallicProperty] (click on the image to see a
 larger version).
@@ -248,7 +247,7 @@ The effect of `roughness` on metallic surfaces is shown in figure [roughnessCond
 When refraction through an object is enabled (using a `refractonType` of `thin` or `solid`), the
 `roughness` property will also affect the refractions, as shown in figure
 [roughnessRefractionProperty] (click on the image to see a larger version).
-                             
+
 ![Figure [roughnessRefractionProperty]: Refractive sphere with `roughness` varying from 0.0
 (left) to 1.0 (right)](images/materials/refraction_roughness.png)

@@ -307,7 +306,7 @@ The sheen color controls the color appearance and strength of an optional sheen
 base layer described by the properties above. The sheen layer always sits below the clear coat layer
 if such a layer is present.

-The sheen layer can be used to represent cloth and fabric materials. Please refer to 
+The sheen layer can be used to represent cloth and fabric materials. Please refer to
 section [Cloth model] for more information about cloth and fabric materials.

 The effect of `sheenColor` is shown in figure [materialSheenColor]
@@ -520,14 +519,14 @@ light to bend further away from the initial path.

 Table [commonMatIOR] describes acceptable refractive indices for various types of materials.

-Material                   |        IOR       
+Material                   |        IOR
 --------------------------:|:-----------------
 Air                        | 1.0
-Water                      | 1.33             
-Common liquids             | 1.33 to 1.5      
-Common gemstones           | 1.58 to 2.33     
-Plastics, glass            | 1.5 to 1.58      
-Other dielectric materials | 1.33 to 1.58     
+Water                      | 1.33
+Common liquids             | 1.33 to 1.5
+Common gemstones           | 1.58 to 2.33
+Plastics, glass            | 1.5 to 1.58
+Other dielectric materials | 1.33 to 1.58
 [Table [commonMatIOR]: Index of refraction of common materials]

 The appearance of a refractive material will greatly depend on the `refractionType` and
@@ -992,13 +991,10 @@ Type

 Value
 :     Each entry is an object with the properties `name` and `type`, both of `string` type. The
-      name must be a valid GLSL identifier. Entries have an optional `precision`, which can be
+      name must be a valid GLSL identifier. Entries also have an optional `precision`, which can be
      one of `default` (best precision for the platform, typically `high` on desktop, `medium` on
      mobile), `low`, `medium`, `high`. The type must be one of the types described in
-      table [materialParamsTypes]. For Android external textures, entries also have an optional 
-      transformName parameter to specify the name of the material parameter that will be 
-      used to expose the transform matrix associated with the external sampler. In iOS and Vulkan,
-      this will always be identity. 
+      table [materialParamsTypes].

         Type          |            Description
 :----------------------|:---------------------------------
@@ -1027,8 +1023,12 @@ samplerCubemap         | Cubemap texture
 [Table [materialParamsTypes]: Material parameter types]

 Samplers
-:     Sampler types can also specify a `format` which can be either `int` or `float` (defaults to
-      `float`).
+:     Sampler types can specify additional options:
+
+      - `format`: either `int` or `float` (defaults to `float`).
+      - `stages`: array of strings containing the list of shader stages this
+        sampler can be accessed from. Each entry must be either `vertex` or
+        `fragment` (defaults to both).

 Arrays
 :     A parameter can define an array of values by appending `[size]` after the type name, where
@@ -1091,30 +1091,37 @@ Value
    `bool` or `number`, depending on the `type` of the constant. The type must be one of the types
    described in table [materialConstantsTypes].

-         Type          |            Description                   |      Default
-:----------------------|:-----------------------------------------|:------------------
-int                    | A signed, 32 bit GLSL int                |         0
-float                  | A single-precision GLSL float            |         0.0
-bool                   | A GLSL bool                              |         false
+    Constants may also be specified as mutable by setting the `mutable` property to `true`. Only
+    `bool` spec constants may be specified as mutable.
+
+| Type  | Description                   | Default | May be mutable? |
+|:------|:------------------------------|:--------|-----------------|
+| int   | A signed, 32 bit GLSL int     |         | no              |
+| float | A single-precision GLSL float | 0.0     | no              |
+| bool  | A GLSL bool                   | false   | yes             |
 [Table [materialConstantsTypes]: Material constants types]

 Description
 :   Lists the constant parameters accepted by your material. These constants can be set, or
    "specialized", at runtime when loading a material package. Multiple materials can be loaded from
-    the same material package with differing constant parameter specializations. Once a material is
-    loaded from a material package, its constant parameters cannot be changed. Compared to regular
-    parameters, constant parameters allow the compiler to generate more efficient code. Access
-    constant parameters from the shader by prefixing the name with `materialConstant_`. For example,
-    a constant parameter named `myConstant` is accessed in the shader as
-    `materialConstant_myConstant`. If a constant parameter is not set at runtime, the default is
-    used.
+    the same material package with differing constant parameter specializations. If a constant
+    parameter is specialized as mutable, it may be changed at any time on a per-instance basis via
+    `MaterialInstance::setConstant(name, value)`. Otherwise, once a material is loaded from a
+    material package, its constant parameters cannot be changed.
+
+    Compared to regular parameters, constant parameters allow the compiler to generate more
+    efficient code. Access constant parameters from the shader by prefixing the name with
+    `materialConstant_`. For example, a constant parameter named `myConstant` is accessed in the
+    shader as `materialConstant_myConstant`. If a constant parameter is not set at runtime, the
+    default is used.

 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ JSON
 material {
    constants : [
        {
           name : overrideAlpha,
-           type : bool
+           type : bool,
+           mutable : true,
        },
        {
           name : customAlpha,
@@ -1273,9 +1280,6 @@ Description
      when selecting any shading model that is not `unlit`. See the shader sections of this document
      for more information on how to access these attributes from the shaders.

-!!! Note: Interaction with custom variables
-    When the `color` attribute is specified, only four custom variables are available instead of five.
-
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ JSON
 material {
    parameters : [
@@ -1306,7 +1310,7 @@ Type
 :    array of `string`

 Value
-:     Up to 5 strings, each must be a valid GLSL identifier.
+:     Up to 4 strings, each must be a valid GLSL identifier.

 Description
 :     Defines custom interpolants (or variables) that are output by the material's vertex shader.
@@ -1322,10 +1326,6 @@ Description
      particular if `default` is specified the default precision is used is the fragment shader
      (`mediump`) and in the vertex shader (`highp`).

-!!! Warning: Interaction with required attributes
-    If the `color` attribute is specified in the `required` list, then only four variables can be used
-    instead of five.
-
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ JSON
 material {
    name : Skybox,
@@ -2560,7 +2560,7 @@ standard skybox material. It produces a list of 2 parameters, named `showSun` an
 respectively a boolean and a cubemap texture.

 ```text
-$ matc --reflect parameters filament/src/materials/skybox.mat 
+$ matc --reflect parameters filament/src/materials/skybox.mat
 {
  "parameters": [
    {
@@ -2576,7 +2576,7 @@ $ matc --reflect parameters filament/src/materials/skybox.mat
    }
  ]
 }
-``` 
+```

 ### --variant-filter

@@ -146,7 +146,7 @@ This document is part of the <a href="https://github.com/google/filament">Filame
 <ul>
 <li class="minus"><a href="https://github.com/romainguy">Romain Guy</a>, <a href="https://twitter.com/romainguy">@romainguy</a>
 </li>
-<li class="minus"><a href="https://github.com/pixelflinger">Mathias Agopian</a>, <a href="https://bsky.app/profile/pixelflinger.bsky.social">@pixelflinger</a></li></ul>
+<li class="minus"><a href="https://github.com/pixelflinger">Mathias Agopian</a>, <a href="https://twitter.com/darthmoosious">@darthmoosious</a></li></ul>
 </p>
 <a class="target" name="overview">&nbsp;</a><a class="target" name="overview">&nbsp;</a><a class="target" name="toc2">&nbsp;</a><h1>Overview</h1>
 <p>
@@ -217,27 +217,26 @@ in <a href="#table_standardproperties" target="_self">table&nbsp;1</a>.
 <div class='table'>
 <a class="target" name="table_standardproperties">&nbsp;</a><table class="table longtable"><tr><th  style="text-align:right"> Property </th><th  style="text-align:left"> Definition </th></tr>
 <tr><td  style="text-align:right"> <strong class="asterisk">baseColor</strong> </td><td  style="text-align:left"> Diffuse albedo for non-metallic surfaces, and specular color for metallic surfaces </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">roughness</strong> </td><td  style="text-align:left"> Perceived smoothness (1.0) or roughness (0.0) of a surface. Smooth surfaces exhibit sharp reflections </td></tr>
 <tr><td  style="text-align:right"> <strong class="asterisk">metallic</strong> </td><td  style="text-align:left"> Whether a surface appears to be dielectric (0.0) or conductor (1.0). Often used as a binary value (0 or 1) </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">roughness</strong> </td><td  style="text-align:left"> Perceived smoothness (1.0) or roughness (0.0) of a surface. Smooth surfaces exhibit sharp reflections </td></tr>
 <tr><td  style="text-align:right"> <strong class="asterisk">reflectance</strong> </td><td  style="text-align:left"> Fresnel reflectance at normal incidence for dielectric surfaces. This directly controls the strength of the reflections </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">ambientOcclusion</strong> </td><td  style="text-align:left"> Defines how much of the ambient light is accessible to a surface point. It is a per-pixel shadowing factor between 0.0 and 1.0 </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">clearCoat</strong> </td><td  style="text-align:left"> Strength of the clear coat layer </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">clearCoatRoughness</strong> </td><td  style="text-align:left"> Perceived smoothness or roughness of the clear coat layer </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">clearCoatNormal</strong> </td><td  style="text-align:left"> A detail normal used to perturb the clear coat layer using <em class="underscore">bump mapping</em> (<em class="underscore">normal mapping</em>) </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">anisotropy</strong> </td><td  style="text-align:left"> Amount of anisotropy in either the tangent or bitangent direction </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">anisotropyDirection</strong> </td><td  style="text-align:left"> Local surface direction in tangent space </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">thickness</strong> </td><td  style="text-align:left"> Thickness of the solid volume of refractive objects </td></tr>
 <tr><td  style="text-align:right"> <strong class="asterisk">sheenColor</strong> </td><td  style="text-align:left"> Strength of the sheen layer </td></tr>
 <tr><td  style="text-align:right"> <strong class="asterisk">sheenRoughness</strong> </td><td  style="text-align:left"> Perceived smoothness or roughness of the sheen layer </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">emissive</strong> </td><td  style="text-align:left"> Additional diffuse albedo to simulate emissive surfaces (such as neons, etc.) This property is mostly useful in an HDR pipeline with a bloom pass </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">clearCoat</strong> </td><td  style="text-align:left"> Strength of the clear coat layer </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">clearCoatRoughness</strong> </td><td  style="text-align:left"> Perceived smoothness or roughness of the clear coat layer </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">anisotropy</strong> </td><td  style="text-align:left"> Amount of anisotropy in either the tangent or bitangent direction </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">anisotropyDirection</strong> </td><td  style="text-align:left"> Local surface direction in tangent space </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">ambientOcclusion</strong> </td><td  style="text-align:left"> Defines how much of the ambient light is accessible to a surface point. It is a per-pixel shadowing factor between 0.0 and 1.0 </td></tr>
 <tr><td  style="text-align:right"> <strong class="asterisk">normal</strong> </td><td  style="text-align:left"> A detail normal used to perturb the surface using <em class="underscore">bump mapping</em> (<em class="underscore">normal mapping</em>) </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">postLightingColor</strong> </td><td  style="text-align:left"> Additional color that can be blended with the result of the lighting computations. See <code>postLightingBlending</code> </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">absorption</strong> </td><td  style="text-align:left"> Absorption factor for refractive objects </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">transmission</strong> </td><td  style="text-align:left"> Defines how much of the diffuse light of a dielectric is transmitted through the object, in other words this defines how transparent an object is </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">ior</strong> </td><td  style="text-align:left"> Index of refraction, either for refractive objects or as an alternative to reflectance </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">microThickness</strong> </td><td  style="text-align:left"> Thickness of the thin layer of refractive objects </td></tr>
 <tr><td  style="text-align:right"> <strong class="asterisk">bentNormal</strong> </td><td  style="text-align:left"> A normal pointing in the average unoccluded direction. Can be used to improve indirect lighting quality </td></tr>
-<tr><td  style="text-align:right"> <strong class="asterisk">shadowStrength</strong> </td><td  style="text-align:left"> Strength factor between 0 and 1 for all shadows received by this material </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">clearCoatNormal</strong> </td><td  style="text-align:left"> A detail normal used to perturb the clear coat layer using <em class="underscore">bump mapping</em> (<em class="underscore">normal mapping</em>) </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">emissive</strong> </td><td  style="text-align:left"> Additional diffuse albedo to simulate emissive surfaces (such as neons, etc.) This property is mostly useful in an HDR pipeline with a bloom pass </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">postLightingColor</strong> </td><td  style="text-align:left"> Additional color that can be blended with the result of the lighting computations. See <code>postLightingBlending</code> </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">ior</strong> </td><td  style="text-align:left"> Index of refraction, either for refractive objects or as an alternative to reflectance </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">transmission</strong> </td><td  style="text-align:left"> Defines how much of the diffuse light of a dielectric is transmitted through the object, in other words this defines how transparent an object is </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">absorption</strong> </td><td  style="text-align:left"> Absorption factor for refractive objects </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">microThickness</strong> </td><td  style="text-align:left"> Thickness of the thin layer of refractive objects </td></tr>
+<tr><td  style="text-align:right"> <strong class="asterisk">thickness</strong> </td><td  style="text-align:left"> Thickness of the solid volume of refractive objects </td></tr>
 </table><center><div class="tablecaption"><b style="font-style:normal;">Table&nbsp;1:</b> Properties of the standard model</div></center></div>
 </p><p>
 The type and range of each property is described in <a href="#table_standardpropertiestypes" target="_self">table&nbsp;2</a>.
@@ -1098,13 +1097,10 @@ non-shader data.

 <dl><dt>Type</dt><dd><p>     array of parameter objects
 </p></dd><dt>Value</dt><dd><p>      Each entry is an object with the properties <code>name</code> and <code>type</code>, both of <code>string</code> type. The
-      name must be a valid GLSL identifier. Entries have an optional <code>precision</code>, which can be
+      name must be a valid GLSL identifier. Entries also have an optional <code>precision</code>, which can be
      one of <code>default</code> (best precision for the platform, typically <code>high</code> on desktop, <code>medium</code> on
      mobile), <code>low</code>, <code>medium</code>, <code>high</code>. The type must be one of the types described in
-      <a href="#table_materialparamstypes" target="_self">table&nbsp;14</a>. For Android external textures, entries also have an optional 
-      transformName parameter to specify the name of the material parameter that will be 
-      used to expose the transform matrix associated with the external sampler. In iOS and Vulkan,
-      this will always be identity. 
+      <a href="#table_materialparamstypes" target="_self">table&nbsp;14</a>.
 </p></dd></dl><div class='table'>
 <a class="target" name="table_materialparamstypes">&nbsp;</a><table class="table longtable"><tr><th  style="text-align:left"> Type </th><th  style="text-align:left"> Description </th></tr>
 <tr><td  style="text-align:left"> bool </td><td  style="text-align:left"> Single boolean </td></tr>
@@ -1326,10 +1322,7 @@ non-shader data.
      required and does not need to be specified. The <code>tangents</code> attribute is automatically required
      when selecting any shading model that is not <code>unlit</code>. See the shader sections of this document
      for more information on how to access these attributes from the shaders.
-</p></dd></dl><div class="admonition note"><div class="admonition-title"> Interaction with custom variables</div>
-</p><p>
-    When the <code>color</code> attribute is specified, only four custom variables are available instead of five.</div>
-</p><pre class="listing tilde"><code><span class="line"></span>material <span class="hljs-punctuation">{</span>
+</p></dd></dl></p><pre class="listing tilde"><code><span class="line"></span>material <span class="hljs-punctuation">{</span>
 <span class="line"></span>    parameters <span class="hljs-punctuation">:</span> <span class="hljs-punctuation">[</span>
 <span class="line"></span>        <span class="hljs-punctuation">{</span>
 <span class="line"></span>           type <span class="hljs-punctuation">:</span> sampler2d<span class="hljs-punctuation">,</span>
@@ -1354,7 +1347,7 @@ non-shader data.
 <p>

 <dl><dt>Type</dt><dd><p>     array of <code>string</code>
-</p></dd><dt>Value</dt><dd><p>      Up to 5 strings, each must be a valid GLSL identifier.
+</p></dd><dt>Value</dt><dd><p>      Up to 4 strings, each must be a valid GLSL identifier.
 </p></dd><dt>Description</dt><dd><p>      Defines custom interpolants (or variables) that are output by the material's vertex shader.
      Each entry of the array defines the name of an  interpolant. The full name in the fragment
      shader is the name of the interpolant with the <code>variable_</code> prefix. For instance, if you
@@ -1367,11 +1360,7 @@ non-shader data.
      In this case the specified precision is used as-is in both fragment and vertex stages, in
      particular if <code>default</code> is specified the default precision is used is the fragment shader
      (<code>mediump</code>) and in the vertex shader (<code>highp</code>).
-</p></dd></dl><div class="admonition warning"><div class="admonition-title"> Interaction with required attributes</div>
-</p><p>
-    If the <code>color</code> attribute is specified in the <code>required</code> list, then only four variables can be used
-    instead of five.</div>
-</p><pre class="listing tilde"><code><span class="line"></span>material <span class="hljs-punctuation">{</span>
+</p></dd></dl></p><pre class="listing tilde"><code><span class="line"></span>material <span class="hljs-punctuation">{</span>
 <span class="line"></span>    name <span class="hljs-punctuation">:</span> Skybox<span class="hljs-punctuation">,</span>
 <span class="line"></span>    parameters <span class="hljs-punctuation">:</span> <span class="hljs-punctuation">[</span>
 <span class="line"></span>        <span class="hljs-punctuation">{</span>
@@ -257,7 +257,6 @@ if (FILAMENT_SUPPORTS_WEBGPU)
    list(APPEND SRCS
            include/backend/platforms/WebGPUPlatform.h
            src/webgpu/platform/WebGPUPlatform.cpp
-            src/webgpu/SpdMipmapGenerator/SpdMipmapGenerator.cpp
            src/webgpu/WebGPUBufferBase.cpp
            src/webgpu/WebGPUBufferBase.h
            src/webgpu/WebGPUBufferObject.cpp
@@ -269,18 +268,12 @@ if (FILAMENT_SUPPORTS_WEBGPU)
            src/webgpu/WebGPUDescriptorSetLayout.h
            src/webgpu/WebGPUDriver.cpp
            src/webgpu/WebGPUDriver.h
-            src/webgpu/WebGPUFence.cpp
-            src/webgpu/WebGPUFence.h
            src/webgpu/WebGPUIndexBuffer.cpp
            src/webgpu/WebGPUIndexBuffer.h
-            src/webgpu/WebGPUMsaaTextureResolver.cpp
-            src/webgpu/WebGPUMsaaTextureResolver.h
            src/webgpu/WebGPUPipelineCreation.cpp
            src/webgpu/WebGPUPipelineCreation.h
            src/webgpu/WebGPUProgram.cpp
            src/webgpu/WebGPUProgram.h
-            src/webgpu/WebGPURenderPassMipmapGenerator.cpp
-            src/webgpu/WebGPURenderPassMipmapGenerator.h
            src/webgpu/WebGPURenderPrimitive.h
            src/webgpu/WebGPURenderTarget.cpp
            src/webgpu/WebGPURenderTarget.h
@@ -509,20 +502,11 @@ if (FILAMENT_SUPPORTS_WEBGPU)
    target_compile_definitions(${TARGET} PRIVATE $<$<BOOL:${FILAMENT_WEBGPU_IMMEDIATE_ERROR_HANDLING}>:FILAMENT_WEBGPU_IMMEDIATE_ERROR_HANDLING>)
 endif()

-# ==================================================================================================
-# Linker flags
-# ==================================================================================================
-
 target_link_libraries(${TARGET} PRIVATE
+        ${OSMESA_LINKER_FLAGS}
        $<$<AND:$<PLATFORM_ID:Linux>,$<CONFIG:Release>>:${LINUX_LINKER_OPTIMIZATION_FLAGS}>
 )

-if (LINUX AND FILAMENT_SUPPORTS_WEBGPU)
-    # Unclear why this needs to be explicit while other linux libs do not, but it is necessary for
-    # WebGPU to build on linux.
-    target_link_libraries(${TARGET} PRIVATE -lxcb)
-endif()
-
 # ==================================================================================================
 # Installation
 # ==================================================================================================
@@ -474,12 +474,7 @@ constexpr std::string_view to_string(DescriptorType type) noexcept {

 enum class DescriptorFlags : uint8_t {
    NONE = 0x00,
-
-    // Indicate a UNIFORM_BUFFER will have dynamic offsets.
-    DYNAMIC_OFFSET = 0x01,
-
-    // To indicate a texture/sampler type should be unfiltered.
-    UNFILTERABLE = 0x02,
+    DYNAMIC_OFFSET = 0x01
 };

 using descriptor_set_t = uint8_t;
@@ -500,12 +495,18 @@ struct DescriptorSetLayoutBinding {
    DescriptorFlags flags = DescriptorFlags::NONE;
    uint16_t count = 0;

+    //  TODO: uncomment when needed.  Note that this class is used as hash key.  We need to ensure
+    //  no uninitialized padding bytes.
+    //    uint8_t externalSamplerDataIndex = EXTERNAL_SAMPLER_DATA_INDEX_UNUSED;
+
    friend bool operator==(DescriptorSetLayoutBinding const& lhs,
            DescriptorSetLayoutBinding const& rhs) noexcept {
        return lhs.type == rhs.type &&
               lhs.flags == rhs.flags &&
               lhs.count == rhs.count &&
               lhs.stageFlags == rhs.stageFlags;
+//               lhs.stageFlags == rhs.stageFlags &&
+//               lhs.externalSamplerDataIndex == rhs.externalSamplerDataIndex;
    }
 };

@@ -1253,6 +1254,26 @@ enum class SamplerCompareFunc : uint8_t {
    N           //!< Never. The depth / stencil test always fails.
 };

+//! this API is copied from (and only applies to) the Vulkan spec.
+//! These specify YUV to RGB conversions.
+enum class SamplerYcbcrModelConversion : uint8_t {
+    RGB_IDENTITY = 0,
+    YCBCR_IDENTITY = 1,
+    YCBCR_709 = 2,
+    YCBCR_601 = 3,
+    YCBCR_2020 = 4,
+};
+
+enum class SamplerYcbcrRange : uint8_t {
+    ITU_FULL = 0,
+    ITU_NARROW = 1,
+};
+
+enum class ChromaLocation : uint8_t {
+    COSITED_EVEN = 0,
+    MIDPOINT = 1,
+};
+
 //! Sampler parameters
 struct SamplerParams {             // NOLINT
    SamplerMagFilter filterMag      : 1;    //!< magnification filter (NEAREST)
@@ -1321,9 +1342,94 @@ static_assert(sizeof(SamplerParams) == 4);
 static_assert(sizeof(SamplerParams) <= sizeof(uint64_t),
        "SamplerParams must be no more than 64 bits");

+//! Sampler parameters
+struct SamplerYcbcrConversion {// NOLINT
+    SamplerYcbcrModelConversion ycbcrModel : 4;
+    TextureSwizzle r : 4;
+    TextureSwizzle g : 4;
+    TextureSwizzle b : 4;
+    TextureSwizzle a : 4;
+    SamplerYcbcrRange ycbcrRange : 1;
+    ChromaLocation xChromaOffset : 1;
+    ChromaLocation yChromaOffset : 1;
+    SamplerMagFilter chromaFilter : 1;
+    uint8_t padding;
+
+    struct Hasher {
+        size_t operator()(const SamplerYcbcrConversion p) const noexcept {
+            // we don't use std::hash<> here, so we don't have to include <functional>
+            return *reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&p));
+        }
+    };
+
+    struct EqualTo {
+        bool operator()(SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs) const noexcept {
+            assert_invariant(lhs.padding == 0);
+            auto* pLhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&lhs));
+            auto* pRhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&rhs));
+            return *pLhs == *pRhs;
+        }
+    };
+
+    struct LessThan {
+        bool operator()(SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs) const noexcept {
+            assert_invariant(lhs.padding == 0);
+            auto* pLhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&lhs));
+            auto* pRhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&rhs));
+            return *pLhs < *pRhs;
+        }
+    };
+
+private:
+    friend bool operator == (SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs)
+            noexcept {
+        return SamplerYcbcrConversion::EqualTo{}(lhs, rhs);
+    }
+    friend bool operator != (SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs)
+            noexcept {
+        return  !SamplerYcbcrConversion::EqualTo{}(lhs, rhs);
+    }
+    friend bool operator < (SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs)
+            noexcept {
+        return SamplerYcbcrConversion::LessThan{}(lhs, rhs);
+    }
+};
+
+static_assert(sizeof(SamplerYcbcrConversion) == 4);
+
+static_assert(sizeof(SamplerYcbcrConversion) <= sizeof(uint64_t),
+        "SamplerYcbcrConversion must be no more than 64 bits");
+
+struct ExternalSamplerDatum {
+    ExternalSamplerDatum(SamplerYcbcrConversion ycbcr, SamplerParams spm, uint32_t extFmt)
+        : YcbcrConversion(ycbcr),
+          samplerParams(spm),
+          externalFormat(extFmt) {}
+    bool operator==(ExternalSamplerDatum const& rhs) const {
+        return (YcbcrConversion == rhs.YcbcrConversion && samplerParams == rhs.samplerParams &&
+                externalFormat == rhs.externalFormat);
+    }
+    struct EqualTo {
+        bool operator()(const ExternalSamplerDatum& lhs,
+                const ExternalSamplerDatum& rhs) const noexcept {
+            return (lhs.YcbcrConversion == rhs.YcbcrConversion &&
+                lhs.samplerParams == rhs.samplerParams &&
+                lhs.externalFormat == rhs.externalFormat);
+        }
+    };
+    SamplerYcbcrConversion YcbcrConversion;
+    SamplerParams samplerParams;
+    uint32_t externalFormat;
+};
+// No implicit padding allowed due to it being a hash key.
+static_assert(sizeof(ExternalSamplerDatum) == 12);
+
 struct DescriptorSetLayout {
    std::variant<utils::StaticString, utils::CString, std::monostate> label;
    utils::FixedCapacityVector<DescriptorSetLayoutBinding> bindings;
+
+//  TODO: uncomment when needed
+//    utils::FixedCapacityVector<ExternalSamplerDatum> externalSamplerData;
 };

 //! blending equation function
@@ -107,36 +107,6 @@ public:
        MULTIVIEW,
    };

-    /**
-     * This controls the priority level for GPU work scheduling, which helps prioritize the
-     * submitted GPU work and enables preemption.
-     */
-    enum class GpuContextPriority : uint8_t {
-        /**
-         * Backend default GPU context priority (typically MEDIUM)
-         */
-        DEFAULT,
-        /**
-         * For non-interactive, deferrable workloads. This should not interfere with standard
-         * applications.
-         */
-        LOW,
-        /**
-         * The default priority level for standard applications.
-         */
-        MEDIUM,
-        /**
-         * For high-priority, latency-sensitive workloads that are more important than standard
-         * applications.
-         */
-        HIGH,
-        /**
-         * The highest priority, intended for system-critical, real-time applications where missing
-         * deadlines is unacceptable (e.g., VR/AR compositors or other system-critical tasks).
-         */
-        REALTIME,
-    };
-
    struct DriverConfig {
        /**
         * Size of handle arena in bytes. Setting to 0 indicates default value is to be used.
@@ -179,20 +149,6 @@ public:
         *      - PlatformEGLAndroid
         */
        bool assertNativeWindowIsValid = false;
-
-        /**
-         * The action to take if a Drawable cannot be acquired. If true, the
-         * frame is aborted instead of panic. This is only supported for:
-         *      - PlatformMetal
-         */
-        bool metalDisablePanicOnDrawableFailure = false;
-
-        /**
-         * GPU context priority level. Controls GPU work scheduling and preemption.
-         * This is only supported for:
-         *      - PlatformEGL
-         */
-        GpuContextPriority gpuContextPriority = GpuContextPriority::DEFAULT;
    };

    Platform() noexcept;
@@ -20,6 +20,7 @@
 #include <utils/CString.h>
 #include <utils/FixedCapacityVector.h>
 #include <utils/Invocable.h>
+#include <utils/bitset.h>

 #include <backend/DriverEnums.h>

@@ -66,6 +67,7 @@ public:
    using DescriptorBindingsInfo = utils::FixedCapacityVector<Descriptor>;
    using DescriptorSetInfo = std::array<DescriptorBindingsInfo, MAX_DESCRIPTOR_SET_COUNT>;
    using SpecializationConstantsInfo = utils::FixedCapacityVector<SpecializationConstant>;
+    using MutableSpecConstantsInfo = utils::bitset8;
    using ShaderBlob = utils::FixedCapacityVector<uint8_t>;
    using ShaderSource = std::array<ShaderBlob, SHADER_TYPE_COUNT>;

@@ -102,7 +104,8 @@ public:
    Program& descriptorBindings(backend::descriptor_set_t set,
            DescriptorBindingsInfo descriptorBindings) noexcept;

-    Program& specializationConstants(SpecializationConstantsInfo specConstants) noexcept;
+    Program& specializationConstants(SpecializationConstantsInfo specConstants,
+            uint32_t firstMutableId, MutableSpecConstantsInfo mutableSpecConstants) noexcept;

    struct PushConstant {
        utils::CString name;
@@ -116,7 +116,7 @@ public:
     * Destroys the object D at Handle<B> and construct a new D in its place
     * e.g.:
     *  Handle<ConcreteTexture> h = allocateAndConstruct(w, h);
-     *  ConcreteTexture* p = destroyAndConstruct(h, w, h);
+     *  ConcreteTexture* p = reconstruct(h, w, h);
     */
    template<typename D, typename B, typename ... ARGS>
    std::enable_if_t<std::is_base_of_v<B, D>, D>*
@@ -80,8 +80,18 @@ Program& Program::attributes(AttributesInfo attributes) noexcept {
    return *this;
 }

-Program& Program::specializationConstants(SpecializationConstantsInfo specConstants) noexcept {
+Program& Program::specializationConstants(SpecializationConstantsInfo specConstants,
+        uint32_t firstMutableId, MutableSpecConstantsInfo mutableSpecConstants) noexcept {
+    // String the two lists together.
    mSpecializationConstants = std::move(specConstants);
+    uint32_t firstMutableIndex = specConstants.size();
+    mSpecializationConstants.reserve(specConstants.size() + mutableSpecConstants.size());
+    for (uint32_t i = 0; i < mutableSpecConstants.size(); i++) {
+        mSpecializationConstants[i + firstMutableIndex] = SpecializationConstant {
+                .id = i + firstMutableId,
+                .value = mutableSpecConstants[i],
+        };
+    }
    return *this;
 }

@@ -53,9 +53,6 @@ PlatformMetal::~PlatformMetal() noexcept {
 }

 Driver* PlatformMetal::createDriver(void* /*sharedContext*/, const Platform::DriverConfig& driverConfig) noexcept {
-    pImpl->mDrawableFailureBehavior = driverConfig.metalDisablePanicOnDrawableFailure
-            ? DrawableFailureBehavior::ABORT_FRAME
-            : DrawableFailureBehavior::PANIC;
    return MetalDriverFactory::create(this, driverConfig);
 }

@@ -66,7 +66,7 @@ static std::string to_string(int const i) { return std::to_string(i); }
 static std::string to_string(float const f) { return "float(" + std::to_string(f) + ")"; }

 static void logCompilationError(ShaderStage shaderType, const char* name, GLuint shaderId,
-        Program::ShaderBlob const& sourceCode) noexcept;
+        CString const& sourceCode) noexcept;
 static void logProgramLinkError(char const* name, GLuint program) noexcept;

 static void process_GOOGLE_cpp_style_line_directive(OpenGLContext const& context, char* source,
@@ -88,7 +88,7 @@ struct ShaderCompilerService::OpenGLProgramToken : ProgramToken {
    ShaderCompilerService& compiler;
    CString const& name;
    FixedCapacityVector<std::pair<CString, uint8_t>> attributes;
-    Program::ShaderSource shaderSourceCode;
+    shaders_source_t shaderSourceCode;
    void* user = nullptr;
    struct {
        shaders_t shaders{};
@@ -122,18 +122,12 @@ struct ShaderCompilerService::OpenGLProgramToken : ProgramToken {
    }

    std::optional<CallbackManager::Handle> handle{};
-
-    // Only valid when the blob functions are provided by users. The validity of this variable
-    // doesn't guarantee that the program was created from the cache blob.
    BlobCacheKey key;

    // Used for the `THREAD_POOL` mode.
    mutable Mutex lock;
    mutable Condition cond;
    bool signaled = false;
-
-    // Indicate this program was created from the cache blob.
-    bool retrievedFromBlobCache = false;
 };

 ShaderCompilerService::OpenGLProgramToken::~OpenGLProgramToken() {
@@ -265,7 +259,6 @@ ShaderCompilerService::program_token_t ShaderCompilerService::createProgram(
    // Try retrieving the cached program blob if available.
    token->gl.program = mBlobCache.retrieve(&token->key, mDriver.mPlatform, program);
    if (token->gl.program) {
-        token->retrievedFromBlobCache = true;
        return token;
    }

@@ -344,15 +337,12 @@ GLuint ShaderCompilerService::getProgram(program_token_t& token) {

    assert_invariant(token);// This function should be called when the token is still alive.

-    // Finalize any pending shader compilation tasks only when the token was created without cache.
-    if (!token->retrievedFromBlobCache) {
-        if (token->compiler.mMode == Mode::THREAD_POOL) {
-            auto const job = token->compiler.mCompilerThreadPool.dequeue(token);
-            if (!job) {
-                // It's likely that the job was already completed. But it may be still being
-                // executed at this moment. Just try waiting for it to avoid a race.
-                token->wait();
-            }
+    if (token->compiler.mMode == Mode::THREAD_POOL) {
+        auto const job = token->compiler.mCompilerThreadPool.dequeue(token);
+        if (!job) {
+            // It's likely that the job was already completed. But it may be still being
+            // executed at this moment. Just try waiting for it to avoid a race.
+            token->wait();
        }
    }

@@ -612,7 +602,7 @@ void ShaderCompilerService::executeTickOps() noexcept {
 #ifndef NDEBUG
            // for debugging we return the original shader source (without the modifications we
            // made here), otherwise the line numbers wouldn't match.
-            token->shaderSourceCode[i] = std::move(shader);
+            token->shaderSourceCode[i] = { shader_src, shader_len };
 #endif
            token->gl.shaders[i] = shaderId;
        }
@@ -758,8 +748,7 @@ void ShaderCompilerService::executeTickOps() noexcept {

 UTILS_NOINLINE
 /* static */ void logCompilationError(ShaderStage shaderType, const char* name,
-        GLuint const shaderId,
-        UTILS_UNUSED_IN_RELEASE Program::ShaderBlob const& sourceCode) noexcept {
+        GLuint const shaderId, UTILS_UNUSED_IN_RELEASE CString const& sourceCode) noexcept {

    { // scope for the temporary string storage
        auto to_string = [](ShaderStage type) -> const char* {
@@ -786,8 +775,7 @@ UTILS_NOINLINE
    }

 #ifndef NDEBUG
-    std::string_view const shader{ reinterpret_cast<const char*>(sourceCode.data()),
-        sourceCode.size() };
+    std::string_view const shader{ sourceCode.data(), sourceCode.size() };
    size_t lc = 1;
    size_t start = 0;
    std::string line;
@@ -58,6 +58,7 @@ class ShaderCompilerService {
 public:
    using program_token_t = std::shared_ptr<OpenGLProgramToken>;
    using shaders_t = std::array<GLuint, Program::SHADER_TYPE_COUNT>;
+    using shaders_source_t = std::array<utils::CString, Program::SHADER_TYPE_COUNT>;

    explicit ShaderCompilerService(OpenGLDriver& driver);

@@ -209,42 +209,10 @@ Driver* PlatformEGL::createDriver(void* sharedContext, const DriverConfig& drive
    }
 #endif

-    // Configure GPU context priority level for scheduling and preemption
-    if (driverConfig.gpuContextPriority != Platform::GpuContextPriority::DEFAULT) {
-        if (extensions.has("EGL_IMG_context_priority")) {
-            EGLint priorityLevel = EGL_CONTEXT_PRIORITY_MEDIUM_IMG;
-            const char* priorityName;
-            switch (driverConfig.gpuContextPriority) {
-                case Platform::GpuContextPriority::DEFAULT:
-                    assert_invariant(false);
-                    break;
-                case Platform::GpuContextPriority::LOW:
-                    priorityLevel = EGL_CONTEXT_PRIORITY_LOW_IMG;
-                    priorityName = "LOW";
-                    break;
-                case Platform::GpuContextPriority::MEDIUM:
-                    priorityLevel = EGL_CONTEXT_PRIORITY_MEDIUM_IMG;
-                    priorityName = "MEDIUM";
-                    break;
-                case Platform::GpuContextPriority::HIGH:
-                    priorityLevel = EGL_CONTEXT_PRIORITY_HIGH_IMG;
-                    priorityName = "HIGH";
-                    break;
-                case Platform::GpuContextPriority::REALTIME:
-                    priorityLevel = EGL_CONTEXT_PRIORITY_HIGH_IMG;
-                    priorityName = "REALTIME(=HIGH)";
-                    break;
-            }
-            contextAttribs[EGL_CONTEXT_PRIORITY_LEVEL_IMG] = priorityLevel;
-            LOG(INFO) << "EGL: Enabling GPU context priority: " << priorityName;
-        } else {
-            LOG(WARNING) << "EGL: GPU context priority requested but not supported";
-        }
-    }
-
    // config use for creating the context
    EGLConfig eglConfig = EGL_NO_CONFIG_KHR;

+
    if (UTILS_UNLIKELY(!ext.egl.KHR_no_config_context)) {
        // find a config we can use if we don't have "EGL_KHR_no_config_context" and that we can use
        // for the dummy pbuffer surface.
@@ -15,10 +15,10 @@
 */

 #include "VulkanBufferProxy.h"
+#include "VulkanCommands.h"
+#include "VulkanMemory.h"

 #include "VulkanBufferCache.h"
-#include "VulkanCommands.h"
-#include "VulkanContext.h"
 #include "VulkanMemory.h"

 using namespace bluevk;
@@ -27,8 +27,7 @@ namespace filament::backend {

 VulkanBufferProxy::VulkanBufferProxy(VmaAllocator allocator, VulkanStagePool& stagePool,
        VulkanBufferCache& bufferCache, VulkanBufferUsage usage, uint32_t numBytes)
-    : mAllocator(allocator),
-      mStagePool(stagePool),
+    : mStagePool(stagePool),
      mBufferCache(bufferCache),
      mBuffer(mBufferCache.acquire(usage, numBytes)),
      mUpdatedOffset(0),
@@ -36,45 +35,11 @@ VulkanBufferProxy::VulkanBufferProxy(VmaAllocator allocator, VulkanStagePool& st

 void VulkanBufferProxy::loadFromCpu(VulkanCommandBuffer& commands, const void* cpuData,
        uint32_t byteOffset, uint32_t numBytes) {
-    // The VulkanBuffer is available if the only object reference is hold by the
-    // `VulkanBufferProxy`. This means that the buffer is not currently referenced by a
-    // `VulkanCommandBuffer`.
-    bool const isAvailable = mBuffer->getCount() == 1;
-
-    if (isAvailable) {
-        // We are up to date with all the update operations, so no need to synchronize with previous
-        // updates.
-        mUpdatedBytes = 0;
-        mUpdatedOffset = 0;
-    }
-
-    // Keep track of the VulkanBuffer usage
-    commands.acquire(mBuffer);
-
-    // Check if we can just memcpy directly to the GPU memory.
-    // This is only allowed for UNIFORMS that are AVAILABLE and the memory is HOST_VISIBLE
-    // (supports memcpy from host). This works regardless if it's a full or partial update of the
-    // buffer.
-    bool const isMemcopyable = mBuffer->getGpuBuffer()->allocationInfo.pMappedData != nullptr;
-    bool const isUniform = getUsage() == VulkanBufferUsage::UNIFORM;
-    bool const useMemcpy =
-            isUniform && isMemcopyable && isAvailable && !FVK_FORCE_STAGING_FOR_BUFFER_UPDATES;
-    if (useMemcpy) {
-        char* dest = static_cast<char*>(mBuffer->getGpuBuffer()->allocationInfo.pMappedData) +
-                     byteOffset;
-        memcpy(dest, cpuData, numBytes);
-        vmaFlushAllocation(mAllocator, mBuffer->getGpuBuffer()->vmaAllocation, byteOffset,
-                numBytes);
-        return;
-    }
-
    // Note: this should be stored within the command buffer before going out of
    // scope, so that the command buffer can manage its lifecycle.
    fvkmemory::resource_ptr<VulkanStage::Segment> stage = mStagePool.acquireStage(numBytes);
-    assert_invariant(stage->memory());
    commands.acquire(stage);
-    memcpy(stage->mapping(), cpuData, numBytes);
-    vmaFlushAllocation(mAllocator, stage->memory(), stage->offset(), numBytes);
+    stage->copy(0, cpuData, numBytes);

    // If there was a previous update, then we need to make sure the following write is properly
    // synced with the previous read.
@@ -160,4 +125,4 @@ VulkanBufferUsage VulkanBufferProxy::getUsage() const noexcept {
    return mBuffer->getGpuBuffer()->usage;
 }

-} // namespace filament::backend
+}// namespace filament::backend
@@ -40,7 +40,6 @@ public:
    VulkanBufferUsage getUsage() const noexcept;

 private:
-    VmaAllocator mAllocator;
    VulkanStagePool& mStagePool;
    VulkanBufferCache& mBufferCache;

@@ -49,6 +48,6 @@ private:
    uint32_t mUpdatedBytes = 0;
 };

-} // namespace filament::backend
+}// namespace filament::backend

-#endif // TNT_FILAMENT_BACKEND_VULKANBUFFERPROXY_H
+#endif// TNT_FILAMENT_BACKEND_VULKANBUFFERPROXY_H
@@ -95,7 +95,7 @@
 #endif

 #ifndef NDEBUG
-#define FVK_DEBUG_FLAGS (FVK_DEBUG_PERFORMANCE | FVK_DEBUG_FORWARDED_FLAG)
+#define FVK_DEBUG_FLAGS (FVK_DEBUG_PERFORMANCE | FVK_DEBUG_FORWARDED_FLAG | FVK_DEBUG_DEBUG_UTILS | FVK_DEBUG_GROUP_MARKERS | FVK_DEBUG_VALIDATION)
 #else
 #define FVK_DEBUG_FLAGS 0
 #endif
@@ -214,8 +214,4 @@ constexpr static const int FVK_MAX_PIPELINE_AGE = FVK_MAX_COMMAND_BUFFERS;
 // destroying any unused pipeline object.
 static_assert(FVK_MAX_PIPELINE_AGE >= FVK_MAX_COMMAND_BUFFERS);

-// Whether the buffer updates always use staging or not. Otherwise its allowed to also use memcpy
-// for buffer updates. Default is false
-constexpr static const bool FVK_FORCE_STAGING_FOR_BUFFER_UPDATES = false;
-
 #endif
@@ -394,13 +394,7 @@ void VulkanDriver::collectGarbage() {
 void VulkanDriver::beginFrame(int64_t monotonic_clock_ns,
        int64_t refreshIntervalNs, uint32_t frameId) {
    FVK_PROFILE_MARKER(PROFILE_NAME_BEGINFRAME);
-
-    // Check if any command have finished and reset all its used resources. The resources
-    // wont be destroyed but their reference count will decreased if the command is already
-    // completed.
-    //
-    // This will let us check if any VulkanBuffer is currently in flight or not.
-    mCommands.gc();
+    // Do nothing.

    if (mAppState.hasExternalSamplers()) {
        mExternalImageManager.onBeginFrame();
@@ -1242,8 +1236,7 @@ void VulkanDriver::updateIndexBuffer(Handle<HwIndexBuffer> ibh, BufferDescriptor
    scheduleDestroy(std::move(p));
 }

-void VulkanDriver::registerBufferObjectStreams(Handle<HwBufferObject> boh,
-        BufferObjectStreamDescriptor&& streams) {
+void VulkanDriver::registerBufferObjectStreams(Handle<HwBufferObject> boh, BufferObjectStreamDescriptor&& streams) {
    // Noop
 }

@@ -34,26 +34,27 @@ namespace {
 static constexpr uint32_t MAX_EMPTY_STAGES_TO_RETAIN = 1;
 constexpr uint32_t STAGE_SIZE = 1048576;

-uint32_t alignValue(uint32_t valueToAlign, uint32_t alignment) {
-    if (alignment == 0) {
-        return valueToAlign;
-    }
-
-    uint32_t remainder = valueToAlign % alignment;
-    return remainder == 0 ? valueToAlign : valueToAlign + (alignment - remainder);
-}
-
 }// namespace

 fvkmemory::resource_ptr<VulkanStage::Segment> VulkanStage::acquireSegment(
-        fvkmemory::ResourceManager* resManager, uint32_t segmentOffset, uint32_t numBytes) {
-    auto segment = fvkmemory::resource_ptr<Segment>::construct(resManager, this, numBytes,
-            segmentOffset, [this](uint32_t offset) { mSegments.erase(offset); });
-    mSegments.insert({ segmentOffset, segment.get() });
-    mCurrentOffset = segmentOffset + numBytes;
+        fvkmemory::ResourceManager* resManager, uint32_t numBytes) {
+    auto segment = fvkmemory::resource_ptr<Segment>::construct(resManager, mAllocator, this,
+            mCurrentOffset, [this](uint32_t offset) { mSegments.erase(offset); });
+    mSegments.insert({ mCurrentOffset, segment.get() });
+    // constexpr uint32_t BLOCK_SIZE = 16;
+    // uint32_t const additional = BLOCK_SIZE - (numBytes % BLOCK_SIZE);
+    // numBytes += (additional != BLOCK_SIZE ? additional : 0);
+    mCurrentOffset += numBytes;
    return segment;
 }

+VkResult VulkanStage::Segment::copy(size_t dstOffset, void const* src, size_t writeSize) {
+    //    uint8_t* mapped = ((uint8_t*) mapping()) + dstOffset;
+    //    memcpy(mapped, src, writeSize);
+    //    return vmaFlushAllocation(mAllocator, memory(), offset() + dstOffset, writeSize);
+    return vmaCopyMemoryToAllocation(mAllocator, src, memory(), offset() + dstOffset, writeSize);
+}
+
 VulkanStagePool::VulkanStagePool(VmaAllocator allocator, fvkmemory::ResourceManager* resManager,
        VulkanCommands* commands, const VkPhysicalDeviceLimits* deviceLimits)
    : mAllocator(allocator),
@@ -61,8 +62,7 @@ VulkanStagePool::VulkanStagePool(VmaAllocator allocator, fvkmemory::ResourceMana
      mCommands(commands),
      mDeviceLimits(deviceLimits) {}

-fvkmemory::resource_ptr<VulkanStage::Segment> VulkanStagePool::acquireStage(uint32_t numBytes,
-        uint32_t alignment) {
+fvkmemory::resource_ptr<VulkanStage::Segment> VulkanStagePool::acquireStage(uint32_t numBytes) {
    // Apply alignment to the byte count to ensure that, when we later flush
    // data written by the host, we only flush the atoms that we modified, and
    // no adjacent atoms.
@@ -72,35 +72,17 @@ fvkmemory::resource_ptr<VulkanStage::Segment> VulkanStagePool::acquireStage(uint
    // equal to the requested size.
    auto iter = mStages.lower_bound(numBytes);

-    // If we have potential buffer candidates, loop through and try to find one
-    // that works with our alignment. Also, set the offset for the buffer.
-    // If we have no buffer, create a new one.
-    VulkanStage* pStage = nullptr;
-    uint32_t segmentOffset = 0;
-    while (iter != mStages.end()) {
-        segmentOffset = alignValue(iter->second->currentOffset(), alignment);
-
-        // Check for overflow + if there's space.
-        if (segmentOffset >= iter->second->currentOffset() &&
-                iter->second->capacity() - numBytes >= segmentOffset) {
-            // This buffer has enough space.
-            pStage = iter->second;
-            mStages.erase(iter);
-            break;
-        }
-
-        // This buffer wasn't suitable. Check the next larger one.
-        ++iter;
-    }
-
-    if (!pStage) {
+    VulkanStage* pStage;
+    if (iter != mStages.end()) {
+        pStage = iter->second;
+        mStages.erase(iter);
+    } else {
        pStage = allocateNewStage(std::max(numBytes, STAGE_SIZE));
    }

    // Note: this allocation updates `currentOffset` and `segments` within
    // the parent stage. When destroyed, it will update `segments`.
-    fvkmemory::resource_ptr<VulkanStage::Segment> pSegment =
-            pStage->acquireSegment(mResManager, segmentOffset, numBytes);
+    fvkmemory::resource_ptr<VulkanStage::Segment> pSegment = pStage->acquireSegment(mResManager, numBytes);

    // Update the stage's metadata, and reinsert it with the remaining segment
    // capacity.
@@ -112,7 +94,12 @@ fvkmemory::resource_ptr<VulkanStage::Segment> VulkanStagePool::acquireStage(uint

 uint32_t VulkanStagePool::alignToNonCoherentAtomSize(uint32_t bytes) {
    VkDeviceSize alignment = mDeviceLimits->nonCoherentAtomSize;
-    return alignValue(bytes, alignment);
+    if (alignment == 0) {
+        return bytes;
+    }
+
+    uint32_t remainder = bytes % alignment;
+    return remainder == 0 ? bytes : bytes + (alignment - remainder);
 }

 VulkanStage* VulkanStagePool::allocateNewStage(uint32_t capacity) {
@@ -146,7 +133,7 @@ VulkanStage* VulkanStagePool::allocateNewStage(uint32_t capacity) {
 #endif
    }

-    return new VulkanStage(memory, buffer, capacity, pMapping);
+    return new VulkanStage(mAllocator, memory, buffer, capacity, pMapping);
 }

 void VulkanStagePool::destroyStage(VulkanStage const*&& stage) {
@@ -156,27 +143,27 @@ void VulkanStagePool::destroyStage(VulkanStage const*&& stage) {
    delete stage;
 }

-fvkmemory::resource_ptr<VulkanStageImage::Resource> VulkanStagePool::acquireImage(
-        PixelDataFormat format, PixelDataType type, uint32_t width, uint32_t height) {
-    // Helper lambda so we can return stage images wrapped as resources that can
-    // be held by command buffers until no longer needed.
-    auto wrapAsResource = [this](VulkanStageImage* image) {
-        auto recycleFn = [this](VulkanStageImage* image) {
-            this->mFreeImages.insert(image);
-        };
-        return fvkmemory::resource_ptr<VulkanStageImage::Resource>::construct(
-            this->mResManager, image, recycleFn);
-    };
-
+VulkanStageImage const* VulkanStagePool::acquireImage(PixelDataFormat format, PixelDataType type,
+        uint32_t width, uint32_t height) {
    const VkFormat vkformat = fvkutils::getVkFormat(format, type);
-    for (auto stageImage : mFreeImages) {
-        if (stageImage->format() == vkformat && stageImage->width() == width && stageImage->height() == height) {
-            mFreeImages.erase(stageImage);
-            stageImage->mLastAccessed = mCurrentFrame;
-            return wrapAsResource(stageImage);
+    for (auto image : mFreeImages) {
+        if (image->format == vkformat && image->width == width && image->height == height) {
+            mFreeImages.erase(image);
+            image->lastAccessed = mCurrentFrame;
+            mUsedImages.push_back(image);
+            return image;
        }
    }

+    VulkanStageImage* image = new VulkanStageImage({
+        .format = vkformat,
+        .width = width,
+        .height = height,
+        .lastAccessed = mCurrentFrame,
+    });
+
+    mUsedImages.push_back(image);
+
    const VkImageCreateInfo imageInfo = {
        .sType = VK_STRUCTURE_TYPE_IMAGE_CREATE_INFO,
        .imageType = VK_IMAGE_TYPE_2D,
@@ -194,19 +181,14 @@ fvkmemory::resource_ptr<VulkanStageImage::Resource> VulkanStagePool::acquireImag
        .usage = VMA_MEMORY_USAGE_CPU_TO_GPU
    };

-    VkImage image;
-    VmaAllocation memory;
    const UTILS_UNUSED VkResult result = vmaCreateImage(mAllocator, &imageInfo, &allocInfo,
-            &image, &memory, nullptr);
+            &image->image, &image->memory, nullptr);

    assert_invariant(result == VK_SUCCESS);

    VkImageAspectFlags const aspectFlags = fvkutils::getImageAspect(vkformat);
    VkCommandBuffer const cmdbuffer = mCommands->get().buffer();

-    VulkanStageImage* stageImage = new VulkanStageImage(
-        vkformat, width, height, memory, image, mCurrentFrame);
-
    // We use VK_IMAGE_LAYOUT_GENERAL here because the spec says:
    // "Host access to image memory is only well-defined for linear images and for image
    // subresources of those images which are currently in either the
@@ -214,13 +196,12 @@ fvkmemory::resource_ptr<VulkanStageImage::Resource> VulkanStagePool::acquireImag
    // vkGetImageSubresourceLayout for a linear image returns a subresource layout mapping that is
    // valid for either of those image layouts."
    fvkutils::transitionLayout(cmdbuffer, {
-            .image = stageImage->image(),
+            .image = image->image,
            .oldLayout = VulkanLayout::UNDEFINED,
            .newLayout = VulkanLayout::STAGING, // (= VK_IMAGE_LAYOUT_GENERAL)
            .subresources = { aspectFlags, 0, 1, 0, 1 },
        });
-
-    return wrapAsResource(stageImage);
+    return image;
 }

 void VulkanStagePool::gc() noexcept {
@@ -268,14 +249,25 @@ void VulkanStagePool::gc() noexcept {
    decltype(mFreeImages) freeImages;
    freeImages.swap(mFreeImages);
    for (auto image : freeImages) {
-        if (image->mLastAccessed < evictionTime) {
-            vmaDestroyImage(mAllocator, image->image(), image->memory());
+        if (image->lastAccessed < evictionTime) {
+            vmaDestroyImage(mAllocator, image->image, image->memory);
            delete image;
        } else {
            mFreeImages.insert(image);
        }
    }

+    // Reclaim images that are no longer being used by any command buffer.
+    decltype(mUsedImages) usedImages;
+    usedImages.swap(mUsedImages);
+    for (auto image : usedImages) {
+        if (image->lastAccessed < evictionTime) {
+            image->lastAccessed = mCurrentFrame;
+            mFreeImages.insert(image);
+        } else {
+            mUsedImages.push_back(image);
+        }
+    }
    FVK_SYSTRACE_END();
 }

@@ -285,8 +277,14 @@ void VulkanStagePool::terminate() noexcept {
    }
    mStages.clear();

+    for (auto image : mUsedImages) {
+        vmaDestroyImage(mAllocator, image->image, image->memory);
+        delete image;
+    }
+    mUsedImages.clear();
+
    for (auto image : mFreeImages) {
-        vmaDestroyImage(mAllocator, image->image(), image->memory());
+        vmaDestroyImage(mAllocator, image->image, image->memory);
        delete image;
    }
    mFreeImages.clear();
@@ -35,8 +35,10 @@ class VulkanCommands;
 // into smaller buffers as needed.
 class VulkanStage {
 public:
-    VulkanStage(VmaAllocation memory, VkBuffer buffer, uint32_t capacity, void* mapping)
-        : mMemory(memory),
+    VulkanStage(VmaAllocator allocator, VmaAllocation memory, VkBuffer buffer, uint32_t capacity,
+            void* mapping)
+        : mAllocator(allocator),
+          mMemory(memory),
          mBuffer(buffer),
          mCapacity(capacity),
          mMapping(mapping) {}
@@ -51,10 +53,10 @@ public:
    public:
        using OnRecycle = std::function<void(uint32_t offset)>;

-        Segment(VulkanStage* parentStage, uint32_t capacity, uint32_t offset,
+        Segment(VmaAllocator allocator, VulkanStage* parentStage, uint32_t offset,
                OnRecycle&& onRecycleFn)
-            : mParentStage(parentStage),
-              mCapacity(capacity),
+            : mAllocator(allocator),
+              mParentStage(parentStage),
              mOffset(offset),
              mOnRecycleFn(onRecycleFn) {}

@@ -70,12 +72,12 @@ public:
        Segment& operator=(const Segment& other) = delete;
        Segment& operator=(Segment&& other) = delete;

-        inline VulkanStage* parentStage() const { return mParentStage; }
-        inline VkBuffer buffer() const { return parentStage()->buffer(); }
-        inline VmaAllocation memory() const { return parentStage()->memory(); }
-        inline uint32_t capacity() const { return mCapacity; }
+        inline VkBuffer buffer() const { return mParentStage->buffer(); }
+        inline VmaAllocation memory() const { return mParentStage->memory(); }
        inline uint32_t offset() const { return mOffset; }

+        VkResult copy(size_t dstOffset, void const* src, size_t writeSize);
+
        inline void* mapping() const {
            return reinterpret_cast<void*>(
                    reinterpret_cast<char*>(mParentStage->mapping()) + offset());
@@ -85,9 +87,9 @@ public:
        // Ensure parent class can access the terminate method.
        friend class VulkanStage;

+        VmaAllocator const mAllocator;
        VulkanStage* const mParentStage;
-        const uint32_t mCapacity;
-        const uint32_t mOffset;
+        uint32_t const mOffset;
        OnRecycle mOnRecycleFn;
    };

@@ -105,13 +107,11 @@ public:
    // Marks a region of the block as "in-use", and provides information about
    // the allocated region to the caller. Note: this assumes that numBytes
    // is aligned to the physical device's nonCoherentAtomSize.
-    // Takes the offset to use as the segment's start offset. It is assumed
-    // that this is greater than the segment's current offset, and it is
-    // undefined behavior if not.
    fvkmemory::resource_ptr<Segment> acquireSegment(fvkmemory::ResourceManager* resManager,
-            uint32_t segmentOffset, uint32_t numBytes);
+            uint32_t numBytes);

 private:
+    VmaAllocator const mAllocator;
    const VmaAllocation mMemory;
    const VkBuffer mBuffer;
    const uint32_t mCapacity;
@@ -126,70 +126,13 @@ private:
    std::unordered_map<uint32_t, Segment*> mSegments;
 };

-class VulkanStageImage {
-  public:
-    class Resource : public fvkmemory::Resource {
-      public:
-        using RecycleFn = std::function<void(VulkanStageImage*)>;
-
-        Resource(VulkanStageImage* image, RecycleFn&& onRecycleFn)
-            : mImage(image),
-              mOnRecycleFn(onRecycleFn)
-        {}
-
-        ~Resource() {
-            if (mOnRecycleFn) {
-                mOnRecycleFn(mImage);
-            }
-        }
-
-        inline VkFormat format() const { return mImage->format(); }
-        inline uint32_t width() const { return mImage->width(); }
-        inline uint32_t height() const { return mImage->height(); }
-        inline VmaAllocation memory() const { return mImage->memory(); }
-        inline VkImage image() const { return mImage->image(); }
-
-      private:
-        Resource() = delete;
-        Resource(const Resource& other) = delete;
-        Resource(Resource&& other) = delete;
-        Resource& operator=(const Resource& other) = delete;
-        Resource& operator=(Resource&& other) = delete;
-
-        VulkanStageImage* const mImage;
-        RecycleFn mOnRecycleFn;
-    };
-
-    VulkanStageImage(VkFormat format, uint32_t width, uint32_t height, VmaAllocation memory,
-            VkImage image, uint64_t lastAccessed)
-        : mFormat(format),
-          mWidth(width),
-          mHeight(height),
-          mMemory(memory),
-          mImage(image),
-          mLastAccessed(lastAccessed) {}
-
-    VulkanStageImage(const VulkanStageImage& other) = delete;
-    VulkanStageImage(VulkanStageImage&& other) = delete;
-    VulkanStageImage& operator=(const VulkanStageImage& other) = delete;
-    VulkanStageImage& operator=(VulkanStageImage&& other) = delete;
-
-    inline VkFormat format() const { return mFormat; }
-    inline uint32_t width() const { return mWidth; }
-    inline uint32_t height() const { return mHeight; }
-    inline VmaAllocation memory() const { return mMemory; }
-    inline VkImage image() const { return mImage; }
-
-  private:
-    const VkFormat mFormat;
-    const uint32_t mWidth;
-    const uint32_t mHeight;
-    const VmaAllocation mMemory;
-    const VkImage mImage;
-
-    uint64_t mLastAccessed;
-    // Denote as a friend so that it can update mLastAccessed.
-    friend class VulkanStagePool;
+struct VulkanStageImage {
+    VkFormat format;
+    uint32_t width;
+    uint32_t height;
+    mutable uint64_t lastAccessed;
+    VmaAllocation memory;
+    VkImage image;
 };

 // Manages a pool of stages, periodically releasing stages that have been unused for a while.
@@ -204,13 +147,10 @@ public:
    // buffers so that we have less objects around that we have to keep track
    // of.
    // This function is NOT thread-safe.
-    // numBytes - the number of bytes required by this segment.
-    // alignment - the multiple to align the buffer offset to
-    fvkmemory::resource_ptr<VulkanStage::Segment> acquireStage(uint32_t numBytes,
-            uint32_t alignment = 0);
+    fvkmemory::resource_ptr<VulkanStage::Segment> acquireStage(uint32_t numBytes);

    // Images have VK_IMAGE_LAYOUT_GENERAL and must not be transitioned to any other layout
-    fvkmemory::resource_ptr<VulkanStageImage::Resource> acquireImage(PixelDataFormat format, PixelDataType type,
+    VulkanStageImage const* acquireImage(PixelDataFormat format, PixelDataType type,
            uint32_t width, uint32_t height);

    // Evicts old unused stages and bumps the current frame number.
@@ -250,7 +190,8 @@ private:
    // Use an ordered multimap for quick (capacity => stage) lookups using lower_bound().
    std::multimap<uint32_t, VulkanStage*> mStages;

-    std::unordered_set<VulkanStageImage*> mFreeImages;
+    std::unordered_set<VulkanStageImage const*> mFreeImages;
+    std::vector<VulkanStageImage const*> mUsedImages;

    // Store the current "time" (really just a frame count) and LRU eviction parameters.
    uint64_t mCurrentFrame = 0;
@@ -219,15 +219,15 @@ VkImageUsageFlags getUsage(VulkanContext const& context, uint8_t samples,
    return usage;
 }

-void adjustedMemcpy(void* mapped, PixelBufferDescriptor const& p, size_t width, size_t height,
-        size_t depth) {
+void adjustedMemcpy(PixelBufferDescriptor const& p, size_t width, size_t height,
+        size_t depth, std::function<void(size_t, uint8_t*, size_t)> cpy) {
    uint8_t* buf = (uint8_t*) p.buffer;
    size_t const pixelSize = PixelBufferDescriptor::computeDataSize(p.format, p.type, 1, 1, 1);
    size_t const pbdStride = p.stride ? p.stride : width;

    // Slow path of copying row by row
    assert_invariant(pbdStride >= width);
-    if (UTILS_UNLIKELY(pixelSize > 0 && (p.left > 0 || p.top > 0 || pbdStride > width))) {
+    if (UTILS_UNLIKELY(p.left > 0 || p.top > 0 || pbdStride > width)) {
        size_t const pbdRowSize =
                PixelBufferDescriptor::computeDataSize(p.format, p.type, pbdStride, 1, p.alignment);
        size_t const pbdHeight = p.size / pixelSize / pbdStride / depth;
@@ -243,15 +243,13 @@ void adjustedMemcpy(void* mapped, PixelBufferDescriptor const& p, size_t width,
            for (size_t y = p.top; y < pbdHeight; y++) {
                uint8_t* buf = (uint8_t*) p.buffer +
                               ((p.left * pixelSize) + (y * pbdRowSize) + (z * pbdLayerSize));
-                uint8_t* curMapped = (uint8_t*) mapped + ((y - p.top) * rowSize + z * layerSize);
-                memcpy(curMapped, buf, writeSize);
+                uint32_t const offset = (y - p.top) * rowSize + z * layerSize;
+                cpy(offset, buf, writeSize);
            }
        }
    } else {
-        // Note: if pixelSize = 0, we're dealing with a compressed format; we
-        // should fall back to the buffer's size.
-        size_t const writeSize = pixelSize > 0 ? pixelSize * (width * height * depth) : p.size;
-        memcpy(mapped, buf, writeSize);
+        size_t const writeSize = pixelSize * (width * height * depth);
+        cpy(0, buf, writeSize);
    }
 }

@@ -519,21 +517,20 @@ void VulkanTexture::updateImage(const PixelBufferDescriptor& data, uint32_t widt
    // Otherwise, use vkCmdCopyBufferToImage.
    size_t const bpp =
            PixelBufferDescriptor::computeDataSize(hostData->format, hostData->type, 1, 1, 1);
-    // Note: if bpp = 0, we're dealing with a compressed format; we should fall
-    // back to the buffer's size.
-    size_t const writeSize = bpp > 0 ? width * height * depth * bpp : hostData->size;
+    size_t const writeSize = width * height * depth * bpp;

    // Note: the following stageSegment must be stored within the command buffer
    // before going out of scope, to ensure proper bookkeeping within the
    // staging buffer pool.
-    uint8_t alignment =
-            fvkutils::getTexelBlockSize(fvkutils::getVkFormat(hostData->format, hostData->type));
    fvkmemory::resource_ptr<VulkanStage::Segment> stageSegment =
-            mState->mStagePool.acquireStage(writeSize, alignment);
+            mState->mStagePool.acquireStage(writeSize);
    assert_invariant(stageSegment->memory());
-    adjustedMemcpy(stageSegment->mapping(), *hostData, width, height, depth);
-    vmaFlushAllocation(mState->mAllocator, stageSegment->memory(), stageSegment->offset(),
-            writeSize);
+    adjustedMemcpy(*hostData, width, height, depth,
+            [&stageSegment](size_t dstOffset, uint8_t* src, size_t numBytes) {
+                stageSegment->copy(dstOffset, src, numBytes);
+            });
+//    vmaFlushAllocation(mState->mAllocator, stageSegment->memory(), stageSegment->offset(),
+//            writeSize);

    VulkanCommandBuffer& commands = mState->mCommands->get();
    VkCommandBuffer const cmdbuf = commands.buffer();
@@ -597,21 +594,21 @@ void VulkanTexture::updateImageWithBlit(const PixelBufferDescriptor& data, uint3
        uint32_t height, uint32_t depth, uint32_t miplevel) {
    // Otherwise, use vkCmdCopyBufferToImage.
    size_t const bpp = PixelBufferDescriptor::computeDataSize(data.format, data.type, 1, 1, 1);
-    // Note: if bpp = 0, we're dealing with a compressed format; we should fall
-    // back to the buffer's size.
-    size_t const writeSize = bpp > 0 ? width * height * depth * bpp : data.size;
+    size_t const writeSize = width * height * depth * bpp;

    void* mapped = nullptr;
-    fvkmemory::resource_ptr<VulkanStageImage::Resource> stage
+    VulkanStageImage const* stage
            = mState->mStagePool.acquireImage(data.format, data.type, width, height);
-    vmaMapMemory(mState->mAllocator, stage->memory(), &mapped);
-    adjustedMemcpy(mapped, data, width, height, depth);
-    vmaUnmapMemory(mState->mAllocator, stage->memory());
-    vmaFlushAllocation(mState->mAllocator, stage->memory(), 0, writeSize);
+    vmaMapMemory(mState->mAllocator, stage->memory, &mapped);
+    adjustedMemcpy(data, width, height, depth,
+            [&mapped](size_t, uint8_t* src, size_t numBytes) {
+                memcpy(mapped, src, numBytes);
+            });
+    vmaUnmapMemory(mState->mAllocator, stage->memory);
+    vmaFlushAllocation(mState->mAllocator, stage->memory, 0, writeSize);

    VulkanCommandBuffer& commands = mState->mCommands->get();
    VkCommandBuffer const cmdbuf = commands.buffer();
-    commands.acquire(stage);
    commands.acquire(fvkmemory::resource_ptr<VulkanTexture>::cast(this));

    // TODO: support blit-based format conversion for 3D images and cubemaps.
@@ -634,7 +631,7 @@ void VulkanTexture::updateImageWithBlit(const PixelBufferDescriptor& data, uint3
    VulkanLayout const oldLayout = getLayout(layer, miplevel);
    transitionLayout(&commands, range, newLayout);

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

    transitionLayout(&commands, range, oldLayout);
@@ -29,8 +29,6 @@ using namespace bluevk;

 namespace filament::backend {

-using namespace fvkutils;
-
 VulkanYcbcrConversionCache::VulkanYcbcrConversionCache(VkDevice device)
    : mDevice(device) {}

@@ -17,8 +17,6 @@
 #ifndef TNT_FILAMENT_BACKEND_VULKANYCBCRCONVERSIONCACHE_H
 #define TNT_FILAMENT_BACKEND_VULKANYCBCRCONVERSIONCACHE_H

-#include "utils/Definitions.h"
-
 #include <backend/DriverEnums.h>

 #include <utils/Hash.h>
@@ -32,7 +30,7 @@ namespace filament::backend {
 class VulkanYcbcrConversionCache {
 public:
    struct Params {
-        fvkutils::SamplerYcbcrConversion conversion = {}; // 4
+        SamplerYcbcrConversion conversion = {}; // 4
        VkFormat format;                        // 4
        uint64_t externalFormat = 0;            // 8
    };
@@ -47,15 +45,16 @@ private:

    struct ConversionEqualTo {
        bool operator()(Params lhs, Params rhs) const noexcept {
-            fvkutils::SamplerYcbcrConversion::EqualTo equal;
+            SamplerYcbcrConversion::EqualTo equal;
            return equal(lhs.conversion, rhs.conversion) &&
-                   lhs.externalFormat == rhs.externalFormat && lhs.format == rhs.format;
+                   lhs.externalFormat == rhs.externalFormat &&
+                   lhs.format == rhs.format;
        }
    };
    using ConversionHashFn = utils::hash::MurmurHashFn<Params>;
    tsl::robin_map<Params, VkSamplerYcbcrConversion, ConversionHashFn, ConversionEqualTo> mCache;
 };

-} // namespace filament::backend
+}// namespace filament::backend

 #endif// TNT_FILAMENT_BACKEND_VULKANYCBCRCONVERSIONCACHE_H
@@ -27,7 +27,6 @@ template ResourceType getTypeEnum<VulkanProgram>() noexcept;
 template ResourceType getTypeEnum<VulkanRenderTarget>() noexcept;
 template ResourceType getTypeEnum<VulkanSwapChain>() noexcept;
 template ResourceType getTypeEnum<VulkanStage::Segment>() noexcept;
-template ResourceType getTypeEnum<VulkanStageImage::Resource>() noexcept;
 template ResourceType getTypeEnum<VulkanRenderPrimitive>() noexcept;
 template ResourceType getTypeEnum<VulkanTexture>() noexcept;
 template ResourceType getTypeEnum<VulkanTextureState>() noexcept;
@@ -59,9 +58,6 @@ ResourceType getTypeEnum() noexcept {
    if constexpr (std::is_same_v<D, VulkanStage::Segment>) {
        return ResourceType::STAGE_SEGMENT;
    }
-    if constexpr (std::is_same_v<D, VulkanStageImage::Resource>) {
-        return ResourceType::STAGE_IMAGE;
-    }
    if constexpr (std::is_same_v<D, VulkanRenderPrimitive>) {
        return ResourceType::RENDER_PRIMITIVE;
    }
@@ -109,8 +105,6 @@ std::string getTypeStr(ResourceType type) {
            return "SwapChain";
        case ResourceType::STAGE_SEGMENT:
            return "Stage::Segment";
-        case ResourceType::STAGE_IMAGE:
-            return "Stage::Image";
        case ResourceType::RENDER_PRIMITIVE:
            return "RenderPrimitive";
        case ResourceType::TEXTURE:
@@ -51,8 +51,7 @@ enum class ResourceType : uint8_t {
    FENCE = 13,
    VULKAN_BUFFER = 14,
    STAGE_SEGMENT = 15,
-    STAGE_IMAGE = 16,
-    UNDEFINED_TYPE = 17,    // Must be the last enum because we use it for iterating over the enums.
+    UNDEFINED_TYPE = 16,    // Must be the last enum because we use it for iterating over the enums.
 };

 template<typename D>
@@ -72,8 +71,6 @@ struct Resource {
          restype(ResourceType::UNDEFINED_TYPE),
          mHandleConsideredDestroyed(false) {}

-    uint32_t getCount() const { return mCount; }
-
 private:
    inline void inc() noexcept {
        mCount++;
@@ -81,9 +81,6 @@ void ResourceManager::destroyWithType(ResourceType type, HandleId id) {
        case ResourceType::STAGE_SEGMENT:
            destruct<VulkanStage::Segment>(Handle<VulkanStage::Segment>(id));
            break;
-        case ResourceType::STAGE_IMAGE:
-            destruct<VulkanStageImage::Resource>(Handle<VulkanStageImage::Resource>(id));
-            break;
        case ResourceType::RENDER_PRIMITIVE:
            destruct<VulkanRenderPrimitive>(Handle<VulkanRenderPrimitive>(id));
            break;
@@ -832,9 +832,6 @@ Driver* VulkanPlatform::createDriver(void* sharedContext,
        context.mPhysicalDeviceFeatures.features.shaderClipDistance = VK_FALSE;
    }

-    // TODO: Add support of VK_KHR_global_priority with `driverConfig.gpuContextPriority`
-    // in VulkanPlatform::createDriver.
-
    ExtensionSet deviceExts;
    // If using a shared context, we do not assume any extensions.
    if (!mImpl->mSharedContext) {
@@ -926,7 +923,7 @@ Driver* VulkanPlatform::createDriver(void* sharedContext,
    // Keep a copy of context for swapchains.
    mImpl->mContext = context;

-    return VulkanDriver::create(this, mImpl->mContext, driverConfig);
+    return VulkanDriver::create(this, context, driverConfig);
 }

 // This needs to be explictly written for
@@ -233,212 +233,6 @@ VkFormat getVkFormat(TextureFormat format) {
    }
 }

-// As per VUID-vkCmdCopyBufferToImage-dstImage-07975 and
-// VUID-vkCmdCopyBufferToImage-dstImage-07978, these provide the texel block
-// sizes for each format (as confirmed using the table at
-// https://registry.khronos.org/vulkan/specs/latest/html/vkspec.html#formats-compatibility-classes).
-// We have not listed values for multi-plane formats, as we do not support them
-// unless they're externally provided.
-uint8_t getTexelBlockSize(VkFormat format) {
-    switch (format) {
-        // 8-bit formats.
-        case VK_FORMAT_R8_UNORM:
-        case VK_FORMAT_R8_SNORM:
-        case VK_FORMAT_R8_USCALED:
-        case VK_FORMAT_R8_SSCALED:
-        case VK_FORMAT_R8_UINT:
-        case VK_FORMAT_R8_SINT:
-        case VK_FORMAT_R8_SRGB:
-            return 1;
-
-        // 16-bit formats.
-        case VK_FORMAT_R16_UNORM:
-        case VK_FORMAT_R16_SNORM:
-        case VK_FORMAT_R16_USCALED:
-        case VK_FORMAT_R16_SSCALED:
-        case VK_FORMAT_R16_UINT:
-        case VK_FORMAT_R16_SINT:
-        case VK_FORMAT_R16_SFLOAT:
-        case VK_FORMAT_R8G8_UNORM:
-        case VK_FORMAT_R8G8_SNORM:
-        case VK_FORMAT_R8G8_USCALED:
-        case VK_FORMAT_R8G8_SSCALED:
-        case VK_FORMAT_R8G8_UINT:
-        case VK_FORMAT_R8G8_SINT:
-        case VK_FORMAT_R8G8_SRGB:
-        case VK_FORMAT_R5G6B5_UNORM_PACK16:
-        case VK_FORMAT_R5G5B5A1_UNORM_PACK16:
-        case VK_FORMAT_R4G4B4A4_UNORM_PACK16:
-            return 2;
-
-        // 24-bit formats.
-        case VK_FORMAT_R8G8B8_UNORM:
-        case VK_FORMAT_R8G8B8_SNORM:
-        case VK_FORMAT_R8G8B8_USCALED:
-        case VK_FORMAT_R8G8B8_SSCALED:
-        case VK_FORMAT_R8G8B8_UINT:
-        case VK_FORMAT_R8G8B8_SINT:
-        case VK_FORMAT_R8G8B8_SRGB:
-        case VK_FORMAT_B8G8R8_UNORM:
-        case VK_FORMAT_B8G8R8_SNORM:
-        case VK_FORMAT_B8G8R8_USCALED:
-        case VK_FORMAT_B8G8R8_SSCALED:
-        case VK_FORMAT_B8G8R8_UINT:
-        case VK_FORMAT_B8G8R8_SINT:
-        case VK_FORMAT_B8G8R8_SRGB:
-            return 3;
-
-        // 32-bit formats.
-        case VK_FORMAT_R32_UINT:
-        case VK_FORMAT_R32_SINT:
-        case VK_FORMAT_R32_SFLOAT:
-        case VK_FORMAT_R16G16_UNORM:
-        case VK_FORMAT_R16G16_SNORM:
-        case VK_FORMAT_R16G16_USCALED:
-        case VK_FORMAT_R16G16_SSCALED:
-        case VK_FORMAT_R16G16_UINT:
-        case VK_FORMAT_R16G16_SINT:
-        case VK_FORMAT_R16G16_SFLOAT:
-        case VK_FORMAT_R8G8B8A8_UNORM:
-        case VK_FORMAT_R8G8B8A8_SNORM:
-        case VK_FORMAT_R8G8B8A8_USCALED:
-        case VK_FORMAT_R8G8B8A8_SSCALED:
-        case VK_FORMAT_R8G8B8A8_UINT:
-        case VK_FORMAT_R8G8B8A8_SINT:
-        case VK_FORMAT_R8G8B8A8_SRGB:
-        case VK_FORMAT_B8G8R8A8_UNORM:
-        case VK_FORMAT_B8G8R8A8_SNORM:
-        case VK_FORMAT_B8G8R8A8_USCALED:
-        case VK_FORMAT_B8G8R8A8_SSCALED:
-        case VK_FORMAT_B8G8R8A8_UINT:
-        case VK_FORMAT_B8G8R8A8_SINT:
-        case VK_FORMAT_B8G8R8A8_SRGB:
-        case VK_FORMAT_A8B8G8R8_UNORM_PACK32:
-        case VK_FORMAT_A8B8G8R8_SNORM_PACK32:
-        case VK_FORMAT_A8B8G8R8_USCALED_PACK32:
-        case VK_FORMAT_A8B8G8R8_SSCALED_PACK32:
-        case VK_FORMAT_A8B8G8R8_UINT_PACK32:
-        case VK_FORMAT_A8B8G8R8_SINT_PACK32:
-        case VK_FORMAT_A8B8G8R8_SRGB_PACK32:
-        case VK_FORMAT_A2B10G10R10_UNORM_PACK32:
-        // Depth and stencil formats.
-        case VK_FORMAT_S8_UINT:
-        case VK_FORMAT_D16_UNORM:
-        case VK_FORMAT_X8_D24_UNORM_PACK32:
-        case VK_FORMAT_D32_SFLOAT:
-        case VK_FORMAT_D24_UNORM_S8_UINT:
-        case VK_FORMAT_D32_SFLOAT_S8_UINT:
-        case VK_FORMAT_B10G11R11_UFLOAT_PACK32:
-        case VK_FORMAT_E5B9G9R9_UFLOAT_PACK32:
-            return 4;
-
-        // 48-bit formats.
-        case VK_FORMAT_R16G16B16_UNORM:
-        case VK_FORMAT_R16G16B16_SNORM:
-        case VK_FORMAT_R16G16B16_USCALED:
-        case VK_FORMAT_R16G16B16_SSCALED:
-        case VK_FORMAT_R16G16B16_UINT:
-        case VK_FORMAT_R16G16B16_SINT:
-        case VK_FORMAT_R16G16B16_SFLOAT:
-            return 6;
-
-        // 64-bit formats.
-        case VK_FORMAT_R32G32_UINT:
-        case VK_FORMAT_R32G32_SINT:
-        case VK_FORMAT_R32G32_SFLOAT:
-        case VK_FORMAT_R16G16B16A16_UNORM:
-        case VK_FORMAT_R16G16B16A16_SNORM:
-        case VK_FORMAT_R16G16B16A16_USCALED:
-        case VK_FORMAT_R16G16B16A16_SSCALED:
-        case VK_FORMAT_R16G16B16A16_UINT:
-        case VK_FORMAT_R16G16B16A16_SINT:
-        case VK_FORMAT_R16G16B16A16_SFLOAT:
-        // Compressed formats.
-        case VK_FORMAT_BC1_RGB_UNORM_BLOCK:
-        case VK_FORMAT_BC1_RGB_SRGB_BLOCK:
-        case VK_FORMAT_BC1_RGBA_UNORM_BLOCK:
-        case VK_FORMAT_BC1_RGBA_SRGB_BLOCK:
-        case VK_FORMAT_BC4_UNORM_BLOCK:
-        case VK_FORMAT_BC4_SNORM_BLOCK:
-        case VK_FORMAT_ETC2_R8G8B8_UNORM_BLOCK:
-        case VK_FORMAT_ETC2_R8G8B8_SRGB_BLOCK:
-        case VK_FORMAT_ETC2_R8G8B8A1_UNORM_BLOCK:
-        case VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK:
-        case VK_FORMAT_EAC_R11_UNORM_BLOCK:
-        case VK_FORMAT_EAC_R11_SNORM_BLOCK:
-            return 8;
-
-        // 96-bit formats.
-        case VK_FORMAT_R32G32B32_UINT:
-        case VK_FORMAT_R32G32B32_SINT:
-        case VK_FORMAT_R32G32B32_SFLOAT:
-            return 12;
-
-        // 128-bit formats.
-        case VK_FORMAT_R32G32B32A32_UINT:
-        case VK_FORMAT_R32G32B32A32_SINT:
-        case VK_FORMAT_R32G32B32A32_SFLOAT:
-        // Compressed formats.
-        case VK_FORMAT_BC2_UNORM_BLOCK:
-        case VK_FORMAT_BC2_SRGB_BLOCK:
-        case VK_FORMAT_BC3_UNORM_BLOCK:
-        case VK_FORMAT_BC3_SRGB_BLOCK:
-        case VK_FORMAT_BC5_UNORM_BLOCK:
-        case VK_FORMAT_BC5_SNORM_BLOCK:
-        case VK_FORMAT_BC6H_SFLOAT_BLOCK:
-        case VK_FORMAT_BC6H_UFLOAT_BLOCK:
-        case VK_FORMAT_BC7_UNORM_BLOCK:
-        case VK_FORMAT_BC7_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_4x4_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_5x4_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_5x5_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_6x5_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_6x6_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_8x5_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_8x6_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_8x8_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_10x5_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_10x6_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_10x8_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_10x10_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_12x10_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_12x12_UNORM_BLOCK:
-        case VK_FORMAT_ASTC_4x4_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_5x4_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_5x5_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_6x5_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_6x6_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_8x5_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_8x6_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_8x8_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_10x5_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_10x6_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_10x8_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_10x10_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_12x10_SRGB_BLOCK:
-        case VK_FORMAT_ASTC_12x12_SRGB_BLOCK:
-        case VK_FORMAT_ETC2_R8G8B8A8_UNORM_BLOCK:
-        case VK_FORMAT_ETC2_R8G8B8A8_SRGB_BLOCK:
-        case VK_FORMAT_EAC_R11G11_UNORM_BLOCK:
-        case VK_FORMAT_EAC_R11G11_SNORM_BLOCK:
-            return 16;
-
-        case VK_FORMAT_UNDEFINED:
-            // In cases where we've explicitly already determined that the
-            // format is not supported, let the rest of the system handle
-            // that explicitly. Return '1' for no alignment.
-            return 1;
-
-        default:
-            // This is the case where there's a format that we added support
-            // for in getVkFormat that we have not added support for in this
-            // function, and should be treated as an error.
-            assert_invariant(false && "Unknown data type, conversion is not supported.");
-            return 0;
-    }
-}
-
-
 VkFormat getVkFormat(PixelDataFormat format, PixelDataType type) {
    if (type == PixelDataType::USHORT_565) return VK_FORMAT_R5G6B5_UNORM_PACK16;
    if (type == PixelDataType::UINT_2_10_10_10_REV) return VK_FORMAT_A2B10G10R10_UNORM_PACK32;
@@ -17,8 +17,6 @@
 #ifndef TNT_FILAMENT_BACKEND_VULKAN_UTILS_CONVERSION_H
 #define TNT_FILAMENT_BACKEND_VULKAN_UTILS_CONVERSION_H

-#include "Definitions.h"
-
 #include <backend/DriverEnums.h>

 #include <private/backend/BackendUtils.h>  // for getFormatSize()
@@ -49,9 +47,6 @@ VkFormat getVkFormatLinear(VkFormat format);
 // than a driver-level Texture format, and can account for a specified byte alignment.
 uint32_t getBytesPerPixel(TextureFormat format);

-// Required for aligning textures in staging buffers.
-uint8_t getTexelBlockSize(VkFormat format);
-
 VkCompareOp getCompareOp(SamplerCompareFunc func);
 VkBlendFactor getBlendFactor(BlendFunction mode);
 VkCullModeFlags getCullMode(CullingMode mode);
@@ -17,8 +17,6 @@
 #ifndef TNT_FILAMENT_BACKEND_VULKAN_UTILS_DEFINITIONS_H
 #define TNT_FILAMENT_BACKEND_VULKAN_UTILS_DEFINITIONS_H

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

@@ -381,81 +379,6 @@ static constexpr uint8_t getFragmentStageShift() noexcept {
 // We have at most 4 descriptor sets. This is to indicate which ones are active.
 using DescriptorSetMask = utils::bitset8;

-//! this API is copied from (and only applies to) the Vulkan spec.
-//! These specify YUV to RGB conversions.
-enum class SamplerYcbcrModelConversion : uint8_t {
-    RGB_IDENTITY = 0,
-    YCBCR_IDENTITY = 1,
-    YCBCR_709 = 2,
-    YCBCR_601 = 3,
-    YCBCR_2020 = 4,
-};
-
-enum class SamplerYcbcrRange : uint8_t {
-    ITU_FULL = 0,
-    ITU_NARROW = 1,
-};
-
-enum class ChromaLocation : uint8_t {
-    COSITED_EVEN = 0,
-    MIDPOINT = 1,
-};
-
-//! Sampler parameters
-struct SamplerYcbcrConversion { // NOLINT
-    SamplerYcbcrModelConversion ycbcrModel : 4;
-    TextureSwizzle r : 4;
-    TextureSwizzle g : 4;
-    TextureSwizzle b : 4;
-    TextureSwizzle a : 4;
-    SamplerYcbcrRange ycbcrRange : 1;
-    ChromaLocation xChromaOffset : 1;
-    ChromaLocation yChromaOffset : 1;
-    SamplerMagFilter chromaFilter : 1;
-    uint8_t padding;
-
-    struct Hasher {
-        size_t operator()(const SamplerYcbcrConversion p) const noexcept {
-            // we don't use std::hash<> here, so we don't have to include <functional>
-            return *reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&p));
-        }
-    };
-
-    struct EqualTo {
-        bool operator()(SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs) const noexcept {
-            assert_invariant(lhs.padding == 0);
-            auto* pLhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&lhs));
-            auto* pRhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&rhs));
-            return *pLhs == *pRhs;
-        }
-    };
-
-    struct LessThan {
-        bool operator()(SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs) const noexcept {
-            assert_invariant(lhs.padding == 0);
-            auto* pLhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&lhs));
-            auto* pRhs = reinterpret_cast<uint32_t const*>(reinterpret_cast<char const*>(&rhs));
-            return *pLhs < *pRhs;
-        }
-    };
-
-private:
-    friend bool operator==(SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs) noexcept {
-        return SamplerYcbcrConversion::EqualTo{}(lhs, rhs);
-    }
-    friend bool operator!=(SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs) noexcept {
-        return !SamplerYcbcrConversion::EqualTo{}(lhs, rhs);
-    }
-    friend bool operator<(SamplerYcbcrConversion lhs, SamplerYcbcrConversion rhs) noexcept {
-        return SamplerYcbcrConversion::LessThan{}(lhs, rhs);
-    }
-};
-
-static_assert(sizeof(SamplerYcbcrConversion) == 4);
-
-static_assert(sizeof(SamplerYcbcrConversion) <= sizeof(uint64_t),
-        "SamplerYcbcrConversion must be no more than 64 bits");
-
 } // namespace filament::backend::fvkutils

 #endif // TNT_FILAMENT_BACKEND_VULKAN_UTILS_DEFINITIONS_H
@@ -1,5 +0,0 @@
-WebGPU does not include a trivial way to create mipmaps, and thus we must provide a render pass or compute pass to generate them.
-
-This directory is the result of porting https://github.com/JolifantoBambla/webgpu-spd to C++, which itself is a WebGPU port of https://github.com/GPUOpen-LibrariesAndSDKs/FidelityFX-SDK/blob/main/docs/samples/single-pass-downsampler.md. 
-
-The first version of our port is primarily from a Gemini "Convert this to C++" request, which worked as an MVP with very few changes. Future commits will likely alter this version significantly, but it is being merged in this early state to facilitate rapid iteration. 
@@ -1,956 +0,0 @@
-#include "SpdMipmapGenerator.h"
-#include <sstream>
-#include <stdexcept>
-// C++ port of https://github.com/JolifantoBambla/webgpu-spd for early experiments
-namespace spd {
-
-// Helper to convert enums to strings for map keys or shader code
-const char* to_string(wgpu::TextureFormat format) {
-    switch (format) {
-        case wgpu::TextureFormat::RGBA8Unorm:
-            return "rgba8unorm";
-        case wgpu::TextureFormat::BGRA8Unorm:
-            return "bgra8unorm";
-        case wgpu::TextureFormat::R32Float:
-            return "r32float";
-        case wgpu::TextureFormat::RG32Float:
-            return "rg32float";
-        case wgpu::TextureFormat::RGBA32Float:
-            return "rgba32float";
-        case wgpu::TextureFormat::R16Float:
-            return "r16float";
-        case wgpu::TextureFormat::RG16Float:
-            return "rg16float";
-        case wgpu::TextureFormat::RGBA16Float:
-            return "rgba16float";
-        // Add other formats as needed
-        default:
-            return "rgba8unorm";
-    }
-}
-
-
-std::string MipmapGenerator::GetFilterCode(SPDFilter filter) {
-    switch (filter) {
-        case SPDFilter::Min:
-            return R"(
-    fn spd_reduce_4(v0: vec4<SPDScalar>, v1: vec4<SPDScalar>, v2: vec4<SPDScalar>, v3: vec4<SPDScalar>) -> vec4<SPDScalar> {
-        return min(min(v0, v1), min(v2, v3));
-    }
-    )";
-        case SPDFilter::Max:
-            return R"(
-    fn spd_reduce_4(v0: vec4<SPDScalar>, v1: vec4<SPDScalar>, v2: vec4<SPDScalar>, v3: vec4<SPDScalar>) -> vec4<SPDScalar> {
-        return max(max(v0, v1), max(v2, v3));
-    }
-    )";
-        case SPDFilter::MinMax:
-            return R"(
-    fn spd_reduce_4(v0: vec4<SPDScalar>, v1: vec4<SPDScalar>, v2: vec4<SPDScalar>, v3: vec4<SPDScalar>) -> vec4<SPDScalar> {
-        let max4 = max(max(v0.xy, v1.xy), max(v2.xy, v3.xy));
-        return vec4<SPDScalar>(min(min(v0.x, v1.x), min(v2.x, v3.x)), max(max4.x, max4.y), 0.0, 0.0);
-    }
-    )";
-        case SPDFilter::Average:
-        default:
-            return R"(
-    fn spd_reduce_4(v0: vec4<SPDScalar>, v1: vec4<SPDScalar>, v2: vec4<SPDScalar>, v3: vec4<SPDScalar>) -> vec4<SPDScalar> {
-        return (v0 + v1 + v2 + v3) * 0.25;
-    }
-    )";
-    }
-}
-
-
-MipmapGenerator::MipmapGenerator(const wgpu::Device& device)
-    : m_device(device) {
-    wgpu::BindGroupLayoutEntry bglEntry{};
-    bglEntry.binding = 0;
-    bglEntry.visibility = wgpu::ShaderStage::Compute;
-    bglEntry.buffer.type = wgpu::BufferBindingType::Uniform;
-    bglEntry.buffer.minBindingSize = 16;
-
-    wgpu::BindGroupLayoutDescriptor bglDesc{};
-    bglDesc.entryCount = 1;
-    bglDesc.entries = &bglEntry;
-    m_internalResourcesBindGroupLayout =
-            m_device.CreateBindGroupLayout(&bglDesc); // Basic BGL for <= 6 mips
-
-    wgpu::Limits deviceLimits;
-    m_device.GetLimits(&deviceLimits);
-    // Max number of *output* mips we can generate in a single pass.
-    // This is device.maxStorageTexturesPerShaderStage - 1 (for the source texture binding),
-    // further capped at 11 output mips (which means 12 total texture bindings: 1 source + 11
-    // outputs). WebGPU minspec for maxStorageTexturesPerShaderStage is 4, so
-    // deviceLimits.maxStorageTexturesPerShaderStage >= 4. Thus, m_maxMipsPerPass will be at least
-    // std::min(4u - 1, 11u) = 3.
-    m_maxMipsPerPass =
-            std::min(static_cast<uint32_t>(deviceLimits.maxStorageTexturesPerShaderStage) - 1, 11u);
-    m_maxArrayLayers = deviceLimits.maxStorageTexturesPerShaderStage;
-
-
-    // If we can generate more than 6 mips in a pass, we need an advanced BGL
-    // that includes atomic counter and mid-mip buffer for levels > 5.
-    if (m_maxMipsPerPass > 6) {
-        std::vector<wgpu::BindGroupLayoutEntry> entriesAdvanced(3);
-        // Entry 0: Uniform buffer (DownsamplePassMeta)
-        entriesAdvanced[0].binding = 0;
-        entriesAdvanced[0].visibility = wgpu::ShaderStage::Compute;
-        entriesAdvanced[0].buffer.type = wgpu::BufferBindingType::Uniform;
-        entriesAdvanced[0].buffer.minBindingSize = 16; // sizeof(DownsamplePassMeta) effectively
-
-        // Entry 1: Storage buffer (spd_global_counter)
-        entriesAdvanced[1].binding = 1;
-        entriesAdvanced[1].visibility = wgpu::ShaderStage::Compute;
-        entriesAdvanced[1].buffer.type = wgpu::BufferBindingType::Storage;
-        entriesAdvanced[1].buffer.minBindingSize = 4; // sizeof(atomic<u32>)
-
-        // Entry 2: Storage buffer (mip_dst_6_buffer)
-        entriesAdvanced[2].binding = 2;
-        entriesAdvanced[2].visibility = wgpu::ShaderStage::Compute;
-        entriesAdvanced[2].buffer.type = wgpu::BufferBindingType::Storage;
-        // Size for array<array<array<vec4<f32>, 64>, 64>> which is 16 (bytes for vec4f32) * 64 * 64
-        // * arrayLayers. The shader defines it as [slice][uv.y][uv.x], so 64x64 per slice.
-        // minBindingSize here is for one slice as a baseline. Actual buffer will be larger for
-        // multiple array layers.
-        entriesAdvanced[2].buffer.minBindingSize = 16 * 64 * 64;
-
-        wgpu::BindGroupLayoutDescriptor bglDescAdvanced{};
-        bglDescAdvanced.label = "SPD Internal BGL (Advanced)";
-        bglDescAdvanced.entryCount = static_cast<uint32_t>(entriesAdvanced.size());
-        bglDescAdvanced.entries = entriesAdvanced.data();
-        m_internalResourcesBindGroupLayout_Advanced =
-                m_device.CreateBindGroupLayout(&bglDescAdvanced);
-    }
-}
-
-void MipmapGenerator::PreparePipelines(wgpu::TextureFormat format, SPDFilter filter,
-        bool halfPrecision) {
-    SPDScalarType scalarType = SanitizeScalarType(format, halfPrecision);
-    // Prepare for a reasonable number of mips, up to m_maxMipsPerPass
-    // The loop should go from 1 up to and including m_maxMipsPerPass.
-    // If m_maxMipsPerPass is 0 (e.g. maxStorageTexturesPerShaderStage <=1 ), this loop won't run.
-    for (uint32_t i = 1; i <= m_maxMipsPerPass; ++i) {
-        GetOrCreatePipeline({ format, scalarType, filter, i });
-    }
-}
-
-SPDScalarType MipmapGenerator::SanitizeScalarType(wgpu::TextureFormat format, bool halfPrecision) {
-    std::string formatStr = to_string(format);
-    std::transform(formatStr.begin(), formatStr.end(), formatStr.begin(), ::tolower);
-
-    SPDScalarType texelType = SPDScalarType::F32; // Default to F32
-    if (formatStr.find("sint") != std::string::npos) {
-        texelType = SPDScalarType::I32;
-    } else if (formatStr.find("uint") != std::string::npos) {
-        texelType = SPDScalarType::U32;
-    }
-
-    if (halfPrecision && texelType == SPDScalarType::F32) {
-        if (m_device.HasFeature(wgpu::FeatureName::ShaderF16)) {
-            return SPDScalarType::F16;
-        } else {
-            // Optional: Log a warning here that halfPrecision was requested for a float format
-            // but the device does not support ShaderF16, so F32 will be used.
-        }
-    } else if (halfPrecision && texelType != SPDScalarType::F32) {
-        // Optional: Log a warning here that halfPrecision was requested for a non-float format.
-    }
-    return texelType;
-}
-
-SPDPipeline& MipmapGenerator::GetOrCreatePipeline(const PipelineCacheKey& key) {
-    uint32_t numMipsForPipeline = std::min(key.numMips, m_maxMipsPerPass);
-    if (m_pipelines.find(key) == m_pipelines.end()) {
-        // Create the pipeline
-        SPDPipeline spdPipeline;
-
-        std::vector<wgpu::BindGroupLayoutEntry> mipsBglEntries;
-        // Bindings are 0 for source, 1 to numMipsForPipeline for destinations
-        for (uint32_t i = 0; i <= numMipsForPipeline; ++i) {
-            wgpu::BindGroupLayoutEntry entry{};
-            entry.binding = i;
-            entry.visibility = wgpu::ShaderStage::Compute;
-            if (i == 0) {
-                entry.texture.sampleType = (key.scalarType == SPDScalarType::I32)
-                                                   ? wgpu::TextureSampleType::Sint
-                                           : (key.scalarType == SPDScalarType::U32)
-                                                   ? wgpu::TextureSampleType::Uint
-                                                   : wgpu::TextureSampleType::UnfilterableFloat;
-                entry.texture.viewDimension = wgpu::TextureViewDimension::e2DArray;
-            } else {
-                entry.storageTexture.access = wgpu::StorageTextureAccess::WriteOnly;
-                entry.storageTexture.format = key.format;
-                entry.storageTexture.viewDimension = wgpu::TextureViewDimension::e2DArray;
-            }
-            mipsBglEntries.push_back(entry);
-        }
-
-        wgpu::BindGroupLayoutDescriptor mipsBglDesc{};
-        mipsBglDesc.entryCount = mipsBglEntries.size();
-        mipsBglDesc.entries = mipsBglEntries.data();
-        spdPipeline.mipsBindGroupLayout = m_device.CreateBindGroupLayout(&mipsBglDesc);
-
-        std::string shaderCode = MakeShaderCode(key.format, GetFilterCode(key.filter),
-                numMipsForPipeline, key.scalarType);
-        wgpu::ShaderModuleWGSLDescriptor wgslDesc{};
-        wgslDesc.code = shaderCode.c_str();
-
-        wgpu::ShaderModuleDescriptor shaderModuleDesc{};
-        shaderModuleDesc.nextInChain = &wgslDesc;
-        wgpu::ShaderModule shaderModule = m_device.CreateShaderModule(&shaderModuleDesc);
-
-        wgpu::BindGroupLayout chosenInternalBGL =
-                (numMipsForPipeline > 6 && m_internalResourcesBindGroupLayout_Advanced)
-                        ? m_internalResourcesBindGroupLayout_Advanced
-                        : m_internalResourcesBindGroupLayout;
-
-        wgpu::BindGroupLayout bgls[] = { spdPipeline.mipsBindGroupLayout, chosenInternalBGL };
-        wgpu::PipelineLayoutDescriptor layoutDesc{};
-        layoutDesc.bindGroupLayoutCount = 2;
-        layoutDesc.bindGroupLayouts = bgls;
-
-        wgpu::ComputePipelineDescriptor pipelineDesc{};
-        pipelineDesc.layout = m_device.CreatePipelineLayout(&layoutDesc);
-        pipelineDesc.compute.module = shaderModule;
-        pipelineDesc.compute.entryPoint = "downsample";
-
-        spdPipeline.pipeline = m_device.CreateComputePipeline(&pipelineDesc);
-        m_pipelines[key] = std::move(spdPipeline);
-    }
-    return m_pipelines[key];
-}
-
-
-void MipmapGenerator::Generate(wgpu::CommandEncoder& commandEncoder, wgpu::Texture srcTexture,
-        const SPDPassConfig& config) {
-    if (config.numMips <= 1 || config.numMips <= config.sourceMipLevel + 1) {
-        return;
-    }
-
-    if (m_maxMipsPerPass == 0) {
-        return;
-    }
-
-    PreparePipelines(srcTexture.GetFormat(), config.filter, config.halfPrecision);
-
-    uint32_t totalSrcArrayLayers = srcTexture.GetDepthOrArrayLayers();
-
-    // Loop over array layer chunks
-    for (uint32_t currentBaseArrayLayer = 0; currentBaseArrayLayer < totalSrcArrayLayers;
-            currentBaseArrayLayer += m_maxArrayLayers) {
-
-        uint32_t arrayLayersThisPass =
-                std::min(m_maxArrayLayers, totalSrcArrayLayers - currentBaseArrayLayer);
-
-        uint32_t mipsToGenerateCount = config.numMips - (config.sourceMipLevel + 1);
-        uint32_t currentSourceMipLevel = config.sourceMipLevel;
-
-        while (mipsToGenerateCount > 0) {
-            uint32_t mipsThisPass = std::min(mipsToGenerateCount, m_maxMipsPerPass);
-
-            SPDPassConfig passSpecificConfig = {};
-            passSpecificConfig.filter = config.filter;
-            passSpecificConfig.halfPrecision = config.halfPrecision;
-            passSpecificConfig.targetTexture =
-                    config.targetTexture ? config.targetTexture : srcTexture;
-            passSpecificConfig.numMips = mipsThisPass;
-            passSpecificConfig.sourceMipLevel = currentSourceMipLevel;
-
-            // Pass baseArrayLayer and numArrayLayers directly to generatePass
-            generatePass(commandEncoder, srcTexture, passSpecificConfig, currentBaseArrayLayer,
-                    arrayLayersThisPass);
-
-            mipsToGenerateCount -= mipsThisPass;
-            currentSourceMipLevel += mipsThisPass;
-        }
-    }
-}
-
-void MipmapGenerator::generatePass(wgpu::CommandEncoder& commandEncoder, wgpu::Texture srcTexture,
-        const SPDPassConfig& passConfig, uint32_t baseArrayLayer, uint32_t numArrayLayers) {
-    uint32_t width = srcTexture.GetWidth() >> passConfig.sourceMipLevel;
-    uint32_t height = srcTexture.GetHeight() >> passConfig.sourceMipLevel;
-
-    uint32_t arrayLayerCountForThisPass = numArrayLayers;
-
-    wgpu::Texture target = passConfig.targetTexture ? passConfig.targetTexture : srcTexture;
-    uint32_t numMipsThisPass = passConfig.numMips;
-
-    if (numMipsThisPass == 0) return;
-
-    SPDScalarType scalarType = SanitizeScalarType(srcTexture.GetFormat(), passConfig.halfPrecision);
-    SPDPipeline& spdPipeline = GetOrCreatePipeline(
-            { target.GetFormat(), scalarType, passConfig.filter, numMipsThisPass });
-
-    // --- Create Bind Group 0 (Mips) ---
-    std::vector<wgpu::BindGroupEntry> mipEntries;
-
-    wgpu::TextureViewDescriptor srcViewDesc{};
-    srcViewDesc.dimension = wgpu::TextureViewDimension::e2DArray;
-    srcViewDesc.baseMipLevel = passConfig.sourceMipLevel;
-    srcViewDesc.mipLevelCount = 1;
-    srcViewDesc.baseArrayLayer = baseArrayLayer;
-    srcViewDesc.arrayLayerCount = arrayLayerCountForThisPass;
-
-    wgpu::BindGroupEntry srcEntry{};
-    srcEntry.binding = 0;
-    srcEntry.textureView = srcTexture.CreateView(&srcViewDesc);
-    mipEntries.push_back(srcEntry);
-
-    for (uint32_t i = 0; i < numMipsThisPass; ++i) {
-        wgpu::TextureViewDescriptor dstViewDesc{};
-        dstViewDesc.dimension = wgpu::TextureViewDimension::e2DArray;
-        dstViewDesc.baseMipLevel = passConfig.sourceMipLevel + i + 1;
-        dstViewDesc.mipLevelCount = 1;
-        dstViewDesc.baseArrayLayer = baseArrayLayer;
-        dstViewDesc.arrayLayerCount = arrayLayerCountForThisPass;
-
-        wgpu::BindGroupEntry dstEntry{};
-        dstEntry.binding = i + 1;
-        dstEntry.textureView = target.CreateView(&dstViewDesc);
-        mipEntries.push_back(dstEntry);
-    }
-
-    wgpu::BindGroupDescriptor mipBindGroupDesc{};
-    mipBindGroupDesc.layout = spdPipeline.mipsBindGroupLayout;
-    mipBindGroupDesc.entryCount = mipEntries.size();
-    mipBindGroupDesc.entries = mipEntries.data();
-    wgpu::BindGroup mipsBindGroup = m_device.CreateBindGroup(&mipBindGroupDesc);
-
-    // --- Create Bind Group 1 (Internal Resources) ---
-    uint32_t widthDiv64 = (width + 63) / 64;
-    uint32_t heightDiv64 = (height + 63) / 64;
-    uint32_t numWorkGroups = widthDiv64 * heightDiv64;
-
-    struct DownsamplePassMeta {
-        uint32_t work_group_offset[2] = { 0, 0 };
-        uint32_t num_work_groups;
-        uint32_t mips;
-        uint32_t padding[12];
-    } meta;
-    meta.num_work_groups = numWorkGroups;
-    meta.mips = numMipsThisPass;
-
-    wgpu::BufferDescriptor metaBufferDesc{};
-    metaBufferDesc.size = sizeof(DownsamplePassMeta);
-    metaBufferDesc.usage = wgpu::BufferUsage::Uniform | wgpu::BufferUsage::CopyDst;
-    wgpu::Buffer metaBuffer = m_device.CreateBuffer(&metaBufferDesc);
-    m_device.GetQueue().WriteBuffer(metaBuffer, 0, &meta, sizeof(meta));
-
-    wgpu::BindGroup internalBindGroup;
-    wgpu::BindGroupLayout chosenInternalBGL =
-            (numMipsThisPass > 6 && m_internalResourcesBindGroupLayout_Advanced)
-                    ? m_internalResourcesBindGroupLayout_Advanced
-                    : m_internalResourcesBindGroupLayout;
-
-    if (numMipsThisPass > 6 && m_internalResourcesBindGroupLayout_Advanced) {
-        wgpu::BufferDescriptor atomicCounterBufferDesc{};
-        atomicCounterBufferDesc.size = sizeof(uint32_t) * arrayLayerCountForThisPass;
-        atomicCounterBufferDesc.usage = wgpu::BufferUsage::Storage | wgpu::BufferUsage::CopyDst;
-        wgpu::Buffer atomicCounterBuffer = m_device.CreateBuffer(&atomicCounterBufferDesc);
-
-        commandEncoder.ClearBuffer(atomicCounterBuffer, 0, WGPU_WHOLE_SIZE);
-
-        wgpu::BufferDescriptor midMipBufferDesc{};
-        midMipBufferDesc.size = 64 * 64 * 16 * arrayLayerCountForThisPass;
-        midMipBufferDesc.usage = wgpu::BufferUsage::Storage;
-        wgpu::Buffer midMipBuffer = m_device.CreateBuffer(&midMipBufferDesc);
-
-        std::vector<wgpu::BindGroupEntry> internalEntries(3);
-        internalEntries[0].binding = 0;
-        internalEntries[0].buffer = metaBuffer;
-        internalEntries[0].size = sizeof(DownsamplePassMeta);
-
-        internalEntries[1].binding = 1;
-        internalEntries[1].buffer = atomicCounterBuffer;
-        internalEntries[1].size = atomicCounterBuffer.GetSize();
-
-        internalEntries[2].binding = 2;
-        internalEntries[2].buffer = midMipBuffer;
-        internalEntries[2].size = midMipBuffer.GetSize();
-
-        wgpu::BindGroupDescriptor internalBindGroupDesc{};
-        internalBindGroupDesc.layout = chosenInternalBGL;
-        internalBindGroupDesc.entryCount = static_cast<uint32_t>(internalEntries.size());
-        internalBindGroupDesc.entries = internalEntries.data();
-        internalBindGroup = m_device.CreateBindGroup(&internalBindGroupDesc);
-    } else {
-        wgpu::BindGroupEntry metaEntry{};
-        metaEntry.binding = 0;
-        metaEntry.buffer = metaBuffer;
-        metaEntry.size = sizeof(DownsamplePassMeta);
-
-        wgpu::BindGroupDescriptor internalBindGroupDesc{};
-        internalBindGroupDesc.layout = chosenInternalBGL;
-        internalBindGroupDesc.entryCount = 1;
-        internalBindGroupDesc.entries = &metaEntry;
-        internalBindGroup = m_device.CreateBindGroup(&internalBindGroupDesc);
-    }
-
-    // --- Dispatch ---
-    wgpu::ComputePassEncoder pass = commandEncoder.BeginComputePass();
-    pass.SetPipeline(spdPipeline.pipeline);
-    pass.SetBindGroup(0, mipsBindGroup);
-    pass.SetBindGroup(1, internalBindGroup);
-    pass.DispatchWorkgroups(widthDiv64, heightDiv64, arrayLayerCountForThisPass);
-    pass.End();
-}
-// Main shader generation logic
-
-// Helper function to check if a string is in a vector of strings
-bool includes(const std::vector<std::string>& vec, const std::string& str) {
-    for (const auto& s: vec) {
-        if (s == str) {
-            return true;
-        }
-    }
-    return false;
-}
-
-std::string MakeShaderCode(wgpu::TextureFormat outputFormat, const std::string& filterOp,
-        unsigned int numMips,       // Assuming a default value for numMips
-        SPDScalarType scalarType) { // Default scalarType
-    std::stringstream ss;
-
-    std::string texelType;
-    if (scalarType == SPDScalarType::I32) {
-        texelType = "i32";
-    } else if (scalarType == SPDScalarType::U32) {
-        texelType = "u32";
-    } else {
-        texelType = "f32";
-    }
-
-    bool useF16 = (scalarType == SPDScalarType::F16);
-
-    std::string filterCode = filterOp;
-    if (filterOp == SPD_FILTER_AVERAGE && !includes({ "f32", "f16" }, texelType)) {
-        // Replace "* 0.25" with "/ 4"
-        size_t pos = filterCode.find("* 0.25");
-        if (pos != std::string::npos) {
-            filterCode.replace(pos, std::string("* 0.25").length(), "/ 4");
-        }
-    }
-
-    // Generate mipsBindings
-    std::string mipsBindings;
-    for (unsigned int i = 0; i < numMips; ++i) {
-        mipsBindings += "@group(0) @binding(" + std::to_string(i + 1) + ") var dst_mip_" +
-                        std::to_string(i + 1) + ": texture_storage_2d_array<" +
-                        to_string(outputFormat) + ", write>;\n";
-    }
-
-    // Generate mipsAccessorBody
-    std::string mipsAccessorBody;
-    for (unsigned int i = 0; i < numMips; ++i) {
-        if (i == 5 && numMips > 6) {
-            mipsAccessorBody += " else if mip == 6 {\n";
-            mipsAccessorBody += "                textureStore(dst_mip_6, uv, slice, " +
-                                (useF16 ? "vec4<" + texelType + ">(value)" : "value") + ");\n";
-            mipsAccessorBody += "                mip_dst_6_buffer[slice][uv.y][uv.x] = value;\n";
-            mipsAccessorBody += "            }";
-        } else {
-            if (i != 0) {
-                mipsAccessorBody += " else ";
-            }
-            mipsAccessorBody += "if mip == " + std::to_string(i + 1) + " {\n";
-            mipsAccessorBody += "                textureStore(dst_mip_" + std::to_string(i + 1) +
-                                ", uv, slice, " +
-                                (useF16 ? "vec4<" + texelType + ">(value)" : "value") + ");\n";
-            mipsAccessorBody += "            }";
-        }
-    }
-
-    std::string mipsAccessor =
-            "fn store_dst_mip(value: vec4<SPDScalar>, uv: vec2<u32>, slice: u32, mip: u32) {\n" +
-            mipsAccessorBody + "\n}";
-    std::string midMipAccessor = "return mip_dst_6_buffer[slice][uv.y][uv.x];";
-
-    // Start building the final shader code string
-    ss << R"(
-// This file is part of the FidelityFX SDK.
-//
-// Copyright (C) 2023 Advanced Micro Devices, Inc.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files(the “Software”), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and /or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions :
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
-// AUTHORS COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-
-// Definitions --------------------------------------------------------------------------------------------------------
-
-)";
-    if (useF16) {
-        ss << "enable f16;\n";
-    }
-    ss << "alias SPDScalar = " << texelType
-       << ";\n\n"; // Using texelType here, assuming SPDScalar maps to it.
-
-    ss << R"(
-// Helpers ------------------------------------------------------------------------------------------------------------
-
-/**
- * A helper function performing a remap 64x1 to 8x8 remapping which is necessary for 2D wave reductions.
- * * The 64-wide lane indices to 8x8 remapping is performed as follows:
- * 00 01 08 09 10 11 18 19
- * 02 03 0a 0b 12 13 1a 1b
- * 04 05 0c 0d 14 15 1c 1d
- * 06 07 0e 0f 16 17 1e 1f
- * 20 21 28 29 30 31 38 39
- * 22 23 2a 2b 32 33 3a 3b
- * 24 25 2c 2d 34 35 3c 3d
- * 26 27 2e 2f 36 37 3e 3f
- * * @param a: The input 1D coordinate to remap.
- *
- * @returns The remapped 2D coordinates.
- */
-fn remap_for_wave_reduction(a: u32) -> vec2<u32> {
-    return vec2<u32>(
-        insertBits(extractBits(a, 2u, 3u), a, 0u, 1u),
-        insertBits(extractBits(a, 3u, 3u), extractBits(a, 1u, 2u), 0u, 2u)
-    );
-}
-
-fn map_to_xy(local_invocation_index: u32) -> vec2<u32> {
-    let sub_xy: vec2<u32> = remap_for_wave_reduction(local_invocation_index % 64);
-    return vec2<u32>(
-        sub_xy.x + 8 * ((local_invocation_index >> 6) % 2),
-        sub_xy.y + 8 * ((local_invocation_index >> 7))
-    );
-}
-
-/*
- * Compute a linear value from a SRGB value.
- * * @param value: The value to convert to linear from SRGB.
- * * @returns A value in SRGB space.
- */
-/*
-fn srgb_to_linear(value: SPDScalar) -> SPDScalar {
-    let j = vec3<SPDScalar>(0.0031308 * 12.92, 12.92, 1.0 / 2.4);
-    let k = vec2<SPDScalar>(1.055, -0.055);
-    return clamp(j.x, value * j.y, pow(value, j.z) * k.x + k.y);
-}
-*/
-
-// Resources & Accessors -----------------------------------------------------------------------------------------------
-struct DownsamplePassMeta {
-    work_group_offset: vec2<u32>,
-    num_work_groups: u32,
-    mips: u32,
-}
-
-// In the original version dst_mip_i is an image2Darray [SPD_MAX_MIP_LEVELS+1], i.e., 12+1, but WGSL doesn't support arrays of textures yet
-// Also these are read_write because for mips 7-13, the workgroup reads from mip level 6 - since most formats don't support read_write access in WGSL yet, we use a single read_write buffer in such cases instead
-@group(0) @binding(0) var src_mip_0: texture_2d_array<)"
-       << texelType << R"(>;
-)" << mipsBindings
-       << R"(
-
-@group(1) @binding(0) var<uniform> downsample_pass_meta : DownsamplePassMeta;
-@group(1) @binding(1) var<storage, read_write> spd_global_counter: array<atomic<u32>>;
-@group(1) @binding(2) var<storage, read_write> mip_dst_6_buffer: array<array<array<vec4<f32>, 64>, 64>>;
-
-fn get_mips() -> u32 {
-    return downsample_pass_meta.mips;
-}
-
-fn get_num_work_groups() -> u32 {
-    return downsample_pass_meta.num_work_groups;
-}
-
-fn get_work_group_offset() -> vec2<u32> {
-    return downsample_pass_meta.work_group_offset;
-}
-
-fn load_src_image(uv: vec2<u32>, slice: u32) -> vec4<SPDScalar> {
-    return vec4<SPDScalar>(textureLoad(src_mip_0, uv, slice, 0));
-}
-
-fn load_mid_mip_image(uv: vec2<u32>, slice: u32) -> vec4<SPDScalar> {
-    )";
-    if (numMips > 6) {
-        ss << midMipAccessor;
-    } else {
-        ss << "return vec4<SPDScalar>();";
-    }
-    ss << R"(
-}
-
-)" << mipsAccessor
-       << R"(
-
-// Workgroup -----------------------------------------------------------------------------------------------------------
-
-var<workgroup> spd_intermediate: array<array<vec4<SPDScalar>, 16>, 16>;
-var<workgroup> spd_counter: atomic<u32>;
-
-fn spd_increase_atomic_counter(slice: u32) {
-    atomicStore(&spd_counter, atomicAdd(&spd_global_counter[slice], 1));
-}
-
-fn spd_get_atomic_counter() -> u32 {
-    return atomicLoad(&spd_counter);
-}
-
-fn spd_reset_atomic_counter(slice: u32) {
-    atomicStore(&spd_global_counter[slice], 0);
-}
-
-// Cotnrol flow --------------------------------------------------------------------------------------------------------
-
-fn spd_barrier() {
-    // in glsl this does: groupMemoryBarrier(); barrier();
-    workgroupBarrier();
-}
-
-// Only last active workgroup should proceed
-fn spd_exit_workgroup(num_work_groups: u32, local_invocation_index: u32, slice: u32) -> bool {
-    // global atomic counter
-    if (local_invocation_index == 0) {
-        spd_increase_atomic_counter(slice);
-    }
-    spd_barrier();
-    return spd_get_atomic_counter() != (num_work_groups - 1);
-}
-
-// Pixel access --------------------------------------------------------------------------------------------------------
-
-)" << filterCode
-       << R"(
-
-fn spd_store(pix: vec2<u32>, out_value: vec4<SPDScalar>, mip: u32, slice: u32) {
-    store_dst_mip(out_value, pix, slice, mip + 1);
-}
-
-fn spd_load_intermediate(x: u32, y: u32) -> vec4<SPDScalar> {
-    return spd_intermediate[x][y];
-}
-
-fn spd_store_intermediate(x: u32, y: u32, value: vec4<SPDScalar>) {
-    spd_intermediate[x][y] = value;
-}
-
-fn spd_reduce_intermediate(i0: vec2<u32>, i1: vec2<u32>, i2: vec2<u32>, i3: vec2<u32>) -> vec4<SPDScalar> {
-    let v0 = spd_load_intermediate(i0.x, i0.y);
-    let v1 = spd_load_intermediate(i1.x, i1.y);
-    let v2 = spd_load_intermediate(i2.x, i2.y);
-    let v3 = spd_load_intermediate(i3.x, i3.y);
-    return spd_reduce_4(v0, v1, v2, v3);
-}
-
-fn spd_reduce_load_4(base: vec2<u32>, slice: u32) -> vec4<SPDScalar> {
-    let v0 = load_src_image(base + vec2<u32>(0, 0), slice);
-    let v1 = load_src_image(base + vec2<u32>(0, 1), slice);
-    let v2 = load_src_image(base + vec2<u32>(1, 0), slice);
-    let v3 = load_src_image(base + vec2<u32>(1, 1), slice);
-    return spd_reduce_4(v0, v1, v2, v3);
-}
-
-fn spd_reduce_load_mid_mip_4(base: vec2<u32>, slice: u32) -> vec4<SPDScalar> {
-    let v0 = load_mid_mip_image(base + vec2<u32>(0, 0), slice);
-    let v1 = load_mid_mip_image(base + vec2<u32>(0, 1), slice);
-    let v2 = load_mid_mip_image(base + vec2<u32>(1, 0), slice);
-    let v3 = load_mid_mip_image(base + vec2<u32>(1, 1), slice);
-    return spd_reduce_4(v0, v1, v2, v3);
-}
-
-// Main logic ---------------------------------------------------------------------------------------------------------
-
-fn spd_downsample_mips_0_1(x: u32, y: u32, workgroup_id: vec2<u32>, local_invocation_index: u32, mip: u32, slice: u32) {
-    var v: array<vec4<SPDScalar>, 4>;
-
-    let workgroup64 = workgroup_id.xy * 64;
-    let workgroup32 = workgroup_id.xy * 32;
-    let workgroup16 = workgroup_id.xy * 16;
-
-    var tex = workgroup64 + vec2<u32>(x * 2, y * 2);
-    var pix = workgroup32 + vec2<u32>(x, y);
-    v[0] = spd_reduce_load_4(tex, slice);
-    spd_store(pix, v[0], 0, slice);
-
-    tex = workgroup64 + vec2<u32>(x * 2 + 32, y * 2);
-    pix = workgroup32 + vec2<u32>(x + 16, y);
-    v[1] = spd_reduce_load_4(tex, slice);
-    spd_store(pix, v[1], 0, slice);
-
-    tex = workgroup64 + vec2<u32>(x * 2, y * 2 + 32);
-    pix = workgroup32 + vec2<u32>(x, y + 16);
-    v[2] = spd_reduce_load_4(tex, slice);
-    spd_store(pix, v[2], 0, slice);
-
-    tex = workgroup64 + vec2<u32>(x * 2 + 32, y * 2 + 32);
-    pix = workgroup32 + vec2<u32>(x + 16, y + 16);
-    v[3] = spd_reduce_load_4(tex, slice);
-    spd_store(pix, v[3], 0, slice);
-
-    if mip <= 1 {
-        return;
-    }
-
-    for (var i = 0u; i < 4u; i++) {
-        spd_store_intermediate(x, y, v[i]);
-        spd_barrier();
-        if local_invocation_index < 64 {
-            v[i] = spd_reduce_intermediate(
-                vec2<u32>(x * 2 + 0, y * 2 + 0),
-                vec2<u32>(x * 2 + 1, y * 2 + 0),
-                vec2<u32>(x * 2 + 0, y * 2 + 1),
-                vec2<u32>(x * 2 + 1, y * 2 + 1)
-            );
-            spd_store(workgroup16 + vec2<u32>(x + (i % 2) * 8, y + (i / 2) * 8), v[i], 1, slice);
-        }
-        spd_barrier();
-    }
-
-    if local_invocation_index < 64 {
-        spd_store_intermediate(x + 0, y + 0, v[0]);
-        spd_store_intermediate(x + 8, y + 0, v[1]);
-        spd_store_intermediate(x + 0, y + 8, v[2]);
-        spd_store_intermediate(x + 8, y + 8, v[3]);
-    }
-}
-
-fn spd_downsample_mip_2(x: u32, y: u32, workgroup_id: vec2<u32>, local_invocation_index: u32, mip: u32, slice: u32) {
-    if local_invocation_index < 64u {
-        let v = spd_reduce_intermediate(
-            vec2<u32>(x * 2 + 0, y * 2 + 0),
-            vec2<u32>(x * 2 + 1, y * 2 + 0),
-            vec2<u32>(x * 2 + 0, y * 2 + 1),
-            vec2<u32>(x * 2 + 1, y * 2 + 1)
-        );
-        spd_store(workgroup_id.xy * 8 + vec2<u32>(x, y), v, mip, slice);
-        // store to LDS, try to reduce bank conflicts
-        // x 0 x 0 x 0 x 0 x 0 x 0 x 0 x 0
-        // 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
-        // 0 x 0 x 0 x 0 x 0 x 0 x 0 x 0 x
-        // 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
-        // x 0 x 0 x 0 x 0 x 0 x 0 x 0 x 0
-        // ...
-        // x 0 x 0 x 0 x 0 x 0 x 0 x 0 x 0
-        spd_store_intermediate(x * 2 + y % 2, y * 2, v);
-    }
-}
-
-fn spd_downsample_mip_3(x: u32, y: u32, workgroup_id: vec2<u32>, local_invocation_index: u32, mip: u32, slice: u32) {
-    if local_invocation_index < 16u {
-        // x 0 x 0
-        // 0 0 0 0
-        // 0 x 0 x
-        // 0 0 0 0
-        let v = spd_reduce_intermediate(
-            vec2<u32>(x * 4 + 0 + 0, y * 4 + 0),
-            vec2<u32>(x * 4 + 2 + 0, y * 4 + 0),
-            vec2<u32>(x * 4 + 0 + 1, y * 4 + 2),
-            vec2<u32>(x * 4 + 2 + 1, y * 4 + 2)
-        );
-        spd_store(workgroup_id.xy * 4 + vec2<u32>(x, y), v, mip, slice);
-        // store to LDS
-        // x 0 0 0 x 0 0 0 x 0 0 0 x 0 0 0
-        // 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
-        // 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
-        // 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
-        // 0 x 0 0 0 x 0 0 0 x 0 0 0 x 0 0
-        // ...
-        // 0 0 x 0 0 0 x 0 0 0 x 0 0 0 x 0
-        // ...
-        // 0 0 0 x 0 0 0 x 0 0 0 x 0 0 0 x
-        // ...
-        spd_store_intermediate(x * 4 + y, y * 4, v);
-    }
-}
-
-fn spd_downsample_mip_4(x: u32, y: u32, workgroup_id: vec2<u32>, local_invocation_index: u32, mip: u32, slice: u32) {
-    if local_invocation_index < 4u {
-        // x 0 0 0 x 0 0 0
-        // ...
-        // 0 x 0 0 0 x 0 0
-        let v = spd_reduce_intermediate(
-            vec2<u32>(x * 8 + 0 + 0 + y * 2, y * 8 + 0),
-            vec2<u32>(x * 8 + 4 + 0 + y * 2, y * 8 + 0),
-            vec2<u32>(x * 8 + 0 + 1 + y * 2, y * 8 + 4),
-            vec2<u32>(x * 8 + 4 + 1 + y * 2, y * 8 + 4)
-        );
-        spd_store(workgroup_id.xy * 2 + vec2<u32>(x, y), v, mip, slice);
-        // store to LDS
-        // x x x x 0 ...
-        // 0 ...
-        spd_store_intermediate(x + y * 2, 0, v);
-    }
-}
-
-fn spd_downsample_mip_5(workgroup_id: vec2<u32>, local_invocation_index: u32, mip: u32, slice: u32) {
-    if local_invocation_index < 1u {
-        // x x x x 0 ...
-        // 0 ...
-        let v = spd_reduce_intermediate(vec2<u32>(0, 0), vec2<u32>(1, 0), vec2<u32>(2, 0), vec2<u32>(3, 0));
-        spd_store(workgroup_id.xy, v, mip, slice);
-    }
-}
-
-fn spd_downsample_next_four(x: u32, y: u32, workgroup_id: vec2<u32>, local_invocation_index: u32, base_mip: u32, mips: u32, slice: u32) {
-    if mips <= base_mip {
-        return;
-    }
-    spd_barrier();
-    spd_downsample_mip_2(x, y, workgroup_id, local_invocation_index, base_mip, slice);
-
-    if mips <= base_mip + 1 {
-        return;
-    }
-    spd_barrier();
-    spd_downsample_mip_3(x, y, workgroup_id, local_invocation_index, base_mip + 1, slice);
-
-    if mips <= base_mip + 2 {
-        return;
-    }
-    spd_barrier();
-    spd_downsample_mip_4(x, y, workgroup_id, local_invocation_index, base_mip + 2, slice);
-
-    if mips <= base_mip + 3 {
-        return;
-    }
-    spd_barrier();
-    spd_downsample_mip_5(workgroup_id, local_invocation_index, base_mip + 3, slice);
-}
-
-fn spd_downsample_last_four(x: u32, y: u32, workgroup_id: vec2<u32>, local_invocation_index: u32, base_mip: u32, mips: u32, slice: u32, exit: bool) {
-    if mips <= base_mip {
-        return;
-    }
-    spd_barrier();
-    if !exit {
-        spd_downsample_mip_2(x, y, workgroup_id, local_invocation_index, base_mip, slice);
-    }
-
-    if mips <= base_mip + 1 {
-        return;
-    }
-    spd_barrier();
-    if !exit {
-        spd_downsample_mip_3(x, y, workgroup_id, local_invocation_index, base_mip + 1, slice);
-    }
-
-    if mips <= base_mip + 2 {
-        return;
-    }
-    spd_barrier();
-    if !exit {
-        spd_downsample_mip_4(x, y, workgroup_id, local_invocation_index, base_mip + 2, slice);
-    }
-
-    if mips <= base_mip + 3 {
-        return;
-    }
-    spd_barrier();
-    if !exit {
-        spd_downsample_mip_5(workgroup_id, local_invocation_index, base_mip + 3, slice);
-    }
-}
-
-fn spd_downsample_mips_6_7(x: u32, y: u32, mips: u32, slice: u32) {
-    var tex = vec2<u32>(x * 4 + 0, y * 4 + 0);
-    var pix = vec2<u32>(x * 2 + 0, y * 2 + 0);
-    let v0 = spd_reduce_load_mid_mip_4(tex, slice);
-    spd_store(pix, v0, 6, slice);
-
-    tex = vec2<u32>(x * 4 + 2, y * 4 + 0);
-    pix = vec2<u32>(x * 2 + 1, y * 2 + 0);
-    let v1 = spd_reduce_load_mid_mip_4(tex, slice);
-    spd_store(pix, v1, 6, slice);
-
-    tex = vec2<u32>(x * 4 + 0, y * 4 + 2);
-    pix = vec2<u32>(x * 2 + 0, y * 2 + 1);
-    let v2 = spd_reduce_load_mid_mip_4(tex, slice);
-    spd_store(pix, v2, 6, slice);
-
-    tex = vec2<u32>(x * 4 + 2, y * 4 + 2);
-    pix = vec2<u32>(x * 2 + 1, y * 2 + 1);
-    let v3 = spd_reduce_load_mid_mip_4(tex, slice);
-    spd_store(pix, v3, 6, slice);
-
-    if mips <= 7 {
-        return;
-    }
-    // no barrier needed, working on values only from the same thread
-
-    let v = spd_reduce_4(v0, v1, v2, v3);
-    spd_store(vec2<u32>(x, y), v, 7, slice);
-    spd_store_intermediate(x, y, v);
-}
-
-fn spd_downsample_last_6(x: u32, y: u32, local_invocation_index: u32, mips: u32, num_work_groups: u32, slice: u32) {
-    if mips <= 6 {
-        return;
-    }
-
-    // increase the global atomic counter for the given slice and check if it's the last remaining thread group:
-    // terminate if not, continue if yes.
-    let exit = spd_exit_workgroup(num_work_groups, local_invocation_index, slice);
-
-    // can't exit directly because subsequent barrier calls break uniform control flow...
-    if !exit {
-        // reset the global atomic counter back to 0 for the next spd dispatch
-        spd_reset_atomic_counter(slice);
-
-        // After mip 5 there is only a single workgroup left that downsamples the remaining up to 64x64 texels.
-        // compute MIP level 6 and 7
-        spd_downsample_mips_6_7(x, y, mips, slice);
-    }
-
-    // compute MIP level 8, 9, 10, 11
-    spd_downsample_last_four(x, y, vec2<u32>(0, 0), local_invocation_index, 8, mips, slice, exit);
-}
-
-/// Downsamples a 64x64 tile based on the work group id.
-/// If after downsampling it's the last active thread group, computes the remaining MIP levels.
-///
-/// @param [in] workGroupID        index of the work group / thread group
-/// @param [in] localInvocationIndex   index of the thread within the thread group in 1D
-/// @param [in] mips             the number of total MIP levels to compute for the input texture
-/// @param [in] numWorkGroups        the total number of dispatched work groups / thread groups for this slice
-/// @param [in] slice             the slice of the input texture
-fn spd_downsample(workgroup_id: vec2<u32>, local_invocation_index: u32, mips: u32, num_work_groups: u32, slice: u32) {
-    let xy = map_to_xy(local_invocation_index);
-    spd_downsample_mips_0_1(xy.x, xy.y, workgroup_id, local_invocation_index, mips, slice);
-    spd_downsample_next_four(xy.x, xy.y, workgroup_id, local_invocation_index, 2, mips, slice);
-)";
-    if (numMips > 6) {
-        ss << "    spd_downsample_last_6(xy.x, xy.y, local_invocation_index, mips, "
-              "num_work_groups, slice);\n";
-    }
-    ss << R"(}
-
-// Entry points -------------------------------------------------------------------------------------------------------
-
-@compute
-@workgroup_size(256, 1, 1)
-fn downsample(@builtin(local_invocation_index) local_invocation_index: u32, @builtin(workgroup_id) workgroup_id: vec3<u32>) {
-    spd_downsample(
-        workgroup_id.xy + get_work_group_offset(),
-        local_invocation_index,
-        get_mips(),
-        get_num_work_groups(),
-        workgroup_id.z
-    );
-}
-)";
-    return ss.str();
-}
-
-
-} // namespace spd
@@ -1,99 +0,0 @@
-#pragma once
-
-#include <optional>
-#include <string>
-#include <tsl/robin_map.h>
-#include <vector>
-#include <webgpu/webgpu_cpp.h>
-// C++ port of https://github.com/JolifantoBambla/webgpu-spd for early experiments
-namespace spd {
-
-// Enum for selecting the downsampling filter.
-enum class SPDFilter { Average, Min, Max, MinMax };
-
-// Enum for shader scalar types.
-enum class SPDScalarType { F32, F16, I32, U32 };
-
-// Configuration for a single mipmap generation pass.
-struct SPDPassConfig {
-    SPDFilter filter = SPDFilter::Average;
-    wgpu::Texture targetTexture = nullptr;
-    uint32_t numMips = 0; // For the public API, this is total desired mips. Internally, mips for
-                          // the current pass.
-    bool halfPrecision = false;
-    uint32_t sourceMipLevel = 0;
-};
-
-// Holds a pipeline and its corresponding bind group layout.
-struct SPDPipeline {
-    wgpu::BindGroupLayout mipsBindGroupLayout = nullptr;
-    wgpu::ComputePipeline pipeline = nullptr;
-};
-
-// Manages pipeline creation, caching, and execution for mipmap generation.
-class MipmapGenerator {
-public:
-    MipmapGenerator(const wgpu::Device& device);
-
-    // Pre-creates pipelines for specified formats and filters.
-    void PreparePipelines(wgpu::TextureFormat format, SPDFilter filter, bool halfPrecision = false);
-
-    // Generates a compute pass for creating mipmaps.
-    void Generate(wgpu::CommandEncoder& commandEncoder, wgpu::Texture srcTexture,
-            const SPDPassConfig& config);
-
-private:
-    void generatePass(wgpu::CommandEncoder& commandEncoder, wgpu::Texture srcTexture,
-            const SPDPassConfig& passConfig, uint32_t baseArrayLayer,
-            uint32_t numArrayLayers); // Internal pass config might differ slightly if needed
-
-    wgpu::Device m_device;
-    wgpu::BindGroupLayout m_internalResourcesBindGroupLayout;
-    wgpu::BindGroupLayout m_internalResourcesBindGroupLayout_Advanced = nullptr;
-
-    // Maximum number of mips that can be generated in a single pass.
-    uint32_t m_maxMipsPerPass;
-    uint32_t m_maxArrayLayers;
-
-    // Key for the pipeline cache.
-    struct PipelineCacheKey {
-        wgpu::TextureFormat format;
-        SPDScalarType scalarType;
-        SPDFilter filter;
-        uint32_t numMips;
-
-        bool operator==(const PipelineCacheKey& other) const {
-            return format == other.format && scalarType == other.scalarType &&
-                   filter == other.filter && numMips == other.numMips;
-        }
-    };
-
-    // Hash function for PipelineCacheKey.
-    struct PipelineCacheKeyHash {
-        std::size_t operator()(const PipelineCacheKey& key) const {
-            std::size_t h1 = std::hash<wgpu::TextureFormat>()(key.format);
-            std::size_t h2 = std::hash<SPDScalarType>()(key.scalarType);
-            std::size_t h3 = std::hash<SPDFilter>()(key.filter);
-            std::size_t h4 = std::hash<uint32_t>()(key.numMips);
-            // A simple way to combine hashes.
-            return h1 ^ (h2 << 1) ^ (h3 << 2) ^ (h4 << 3);
-        }
-    };
-
-    // Cached pipelines.
-    tsl::robin_map<PipelineCacheKey, SPDPipeline, PipelineCacheKeyHash> m_pipelines;
-
-    // Helper methods
-    SPDPipeline& GetOrCreatePipeline(const PipelineCacheKey& key);
-    SPDScalarType SanitizeScalarType(wgpu::TextureFormat format, bool halfPrecision);
-    std::string GetFilterCode(SPDFilter filter);
-};
-// Assuming SPD_FILTER_AVERAGE is a string constant
-const std::string SPD_FILTER_AVERAGE = "value * 0.25"; // Original filter operation
-
-// Generates the WGSL shader code dynamically.
-std::string MakeShaderCode(wgpu::TextureFormat outputFormat,
-        const std::string& filterOp = SPD_FILTER_AVERAGE, uint32_t numMips = 0,
-        SPDScalarType scalarType = SPDScalarType::F32);
-
-} // namespace spd
@@ -1,21 +0,0 @@
-MIT License
-
-Copyright (c) 2024 Lukas Herzberger
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
@@ -117,10 +117,10 @@ WebGPUDescriptorSetLayout::WebGPUDescriptorSetLayout(DescriptorSetLayout const&
                samplerEntryInfo.binding = samplerEntry.binding;
                samplerEntry.visibility = wEntry.visibility;
                wEntry.texture.multisampled = isMultiSampledTypeDescriptor(fEntry.type);
+                // TODO: Set once we have the filtering values
                if (isDepthDescriptor(fEntry.type)) {
                    samplerEntry.sampler.type = wgpu::SamplerBindingType::Comparison;
-                } else if (isIntDescriptor(fEntry.type) ||
-                        any(fEntry.flags & DescriptorFlags::UNFILTERABLE)) {
+                } else if (isIntDescriptor(fEntry.type)) {
                    samplerEntry.sampler.type = wgpu::SamplerBindingType::NonFiltering;
                } else {
                    samplerEntry.sampler.type = wgpu::SamplerBindingType::Filtering;
@@ -151,11 +151,8 @@ WebGPUDescriptorSetLayout::WebGPUDescriptorSetLayout(DescriptorSetLayout const&
        if (isDepthDescriptor(fEntry.type)) {
            wEntry.texture.sampleType = wgpu::TextureSampleType::Depth;
        } else if (isFloatDescriptor(fEntry.type)) {
-            if (any(fEntry.flags & DescriptorFlags::UNFILTERABLE)) {
-                wEntry.texture.sampleType = wgpu::TextureSampleType::UnfilterableFloat;
-            } else {
-                wEntry.texture.sampleType = wgpu::TextureSampleType::Float;
-            }
+            // TODO: Set once we have the filtering values
+            wEntry.texture.sampleType = wgpu::TextureSampleType::Float;
        } else if (isIntDescriptor(fEntry.type)) {
            wEntry.texture.sampleType = wgpu::TextureSampleType::Sint;
        } else if (isUnsignedIntDescriptor(fEntry.type)) {
@@ -18,13 +18,11 @@
 #include "WebGPUBufferObject.h"
 #include "WebGPUDescriptorSet.h"
 #include "WebGPUDescriptorSetLayout.h"
-#include "WebGPUFence.h"
 #include "WebGPUIndexBuffer.h"
 #include "WebGPUPipelineCreation.h"
 #include "WebGPUProgram.h"
 #include "WebGPURenderPrimitive.h"
 #include "WebGPURenderTarget.h"
-#include "WebGPUStrings.h"
 #include "WebGPUSwapChain.h"
 #include "WebGPUTexture.h"
 #include "WebGPUVertexBuffer.h"
@@ -43,7 +41,7 @@
 #include <utils/CString.h>
 #include <utils/Hash.h>
 #include <utils/Panic.h>
-#include <utils/compiler.h>
+#include <utils/ostream.h>

 #include <webgpu/webgpu_cpp.h>

@@ -55,8 +53,6 @@
 #include <sstream>
 #include <utility>

-using namespace std::chrono_literals;
-
 namespace filament::backend {

 Driver* WebGPUDriver::create(WebGPUPlatform& platform, const Platform::DriverConfig& driverConfig) noexcept {
@@ -68,15 +64,13 @@ Driver* WebGPUDriver::create(WebGPUPlatform& platform, const Platform::DriverCon

 WebGPUDriver::WebGPUDriver(WebGPUPlatform& platform,
        const Platform::DriverConfig& driverConfig) noexcept
-    : mPlatform{ platform },
-      mAdapter{ mPlatform.requestAdapter(nullptr) },
-      mDevice{ mPlatform.requestDevice(mAdapter) },
-      mQueue{ mDevice.GetQueue() },
-      mRenderPassMipmapGenerator{ mDevice },
-      mSpdComputePassMipmapGenerator{ mDevice },
-      mHandleAllocator{ "Handles", driverConfig.handleArenaSize,
-          driverConfig.disableHandleUseAfterFreeCheck, driverConfig.disableHeapHandleTags } {
+    : mPlatform(platform),
+      mHandleAllocator("Handles", driverConfig.handleArenaSize,
+              driverConfig.disableHandleUseAfterFreeCheck, driverConfig.disableHeapHandleTags) {
+    mAdapter = mPlatform.requestAdapter(nullptr);
+    mDevice = mPlatform.requestDevice(mAdapter);
    mDevice.GetLimits(&mDeviceLimits);
+    mQueue = mDevice.GetQueue();
 }

 WebGPUDriver::~WebGPUDriver() noexcept = default;
@@ -106,7 +100,6 @@ void WebGPUDriver::terminate() {

 void WebGPUDriver::tick(int) {
    mDevice.Tick();
-    mAdapter.GetInstance().ProcessEvents();
 }

 void WebGPUDriver::beginFrame(int64_t monotonic_clock_ns,
@@ -268,9 +261,7 @@ Handle<HwProgram> WebGPUDriver::createProgramS() noexcept {
 }

 Handle<HwFence> WebGPUDriver::createFenceS() noexcept {
-    // The handle must be constructed here, as a synchronous call to get the status
-    // might happen before createFenceR is executed.
-    return allocAndConstructHandle<WebGPUFence, HwFence>();
+    return Handle<HwFence>((Handle<HwFence>::HandleId) mNextFakeHandle++);
 }

 Handle<HwTimerQuery> WebGPUDriver::createTimerQueryS() noexcept {
@@ -343,6 +334,9 @@ void WebGPUDriver::createSwapChainR(Handle<HwSwapChain> sch, void* nativeWindow,
            mDevice, flags);
    assert_invariant(mSwapChain);

+    FWGPU_LOGW << "WebGPU support is highly experimental, in development, and tested for only a "
+                  "small set of simple samples (e.g. hellotriangle and texturedquad), thus issues "
+                  "are likely to be encountered at this stage.";
 #if !FWGPU_ENABLED(FWGPU_PRINT_SYSTEM) && !defined(NDEBUG)
    char printSystemHex[16];
    snprintf(printSystemHex, sizeof(printSystemHex), "%#x", FWGPU_PRINT_SYSTEM);
@@ -454,23 +448,15 @@ void WebGPUDriver::createDefaultRenderTargetR(Handle<HwRenderTarget> renderTarge
 }

 void WebGPUDriver::createRenderTargetR(Handle<HwRenderTarget> renderTargetHandle,
-        const TargetBufferFlags targetFlags, const uint32_t width, const uint32_t height,
+        const TargetBufferFlags targets, const uint32_t width, const uint32_t height,
        const uint8_t samples, const uint8_t layerCount, const MRT color,
        const TargetBufferInfo depth, const TargetBufferInfo stencil) {
-    constructHandle<WebGPURenderTarget>(
-            renderTargetHandle, width, height, samples, layerCount, color, depth, stencil,
-            targetFlags,
-            [&](const Handle<HwTexture> textureHandle) {
-                return handleCast<WebGPUTexture>(textureHandle);
-            },
-            mDevice);
+    constructHandle<WebGPURenderTarget>(renderTargetHandle, width, height, samples, layerCount,
+            color, depth, stencil);
 }

-void WebGPUDriver::createFenceR(Handle<HwFence> fenceHandle, const int /* dummy */) {
-    // the handle was already constructed in createFenceS
-    const auto fence = handleCast<WebGPUFence>(fenceHandle);
-    assert_invariant(mQueue);
-    fence->addMarkerToQueueState(mQueue);
+void WebGPUDriver::createFenceR(Handle<HwFence> fh, int) {
+    //todo
 }

 void WebGPUDriver::createTimerQueryR(Handle<HwTimerQuery> tqh, int) {}
@@ -523,18 +509,13 @@ void WebGPUDriver::updateStreams(CommandStream* driver) {
    //todo
 }

-void WebGPUDriver::destroyFence(Handle<HwFence> fenceHandle) {
-    if (fenceHandle) {
-        destructHandle<WebGPUFence>(fenceHandle);
-    }
+void WebGPUDriver::destroyFence(Handle<HwFence> fh) {
+    //todo
 }

-FenceStatus WebGPUDriver::getFenceStatus(Handle<HwFence> fenceHandle) {
-    const auto fence = handleCast<WebGPUFence>(fenceHandle);
-    if (!fence) {
-        return FenceStatus::ERROR;
-    }
-    return fence->getStatus();
+FenceStatus WebGPUDriver::getFenceStatus(Handle<HwFence> fh) {
+    //todo
+    return FenceStatus::CONDITION_SATISFIED;
 }

 // We create all textures using VK_IMAGE_TILING_OPTIMAL, so our definition of "supported" is that
@@ -591,7 +572,7 @@ bool WebGPUDriver::isParallelShaderCompileSupported() {
 }

 bool WebGPUDriver::isDepthStencilResolveSupported() {
-    return false;
+    return true;
 }

 bool WebGPUDriver::isDepthStencilBlitSupported(const TextureFormat format) {
@@ -624,28 +605,15 @@ uint8_t WebGPUDriver::getMaxDrawBuffers() {
 }

 size_t WebGPUDriver::getMaxUniformBufferSize() {
-    return mDeviceLimits.maxUniformBufferBindingSize;
+    return 16384u;
 }

 size_t WebGPUDriver::getMaxTextureSize(const SamplerType target) {
-    size_t result = 2048u;
-    switch (target) {
-        case SamplerType::SAMPLER_2D:
-        case SamplerType::SAMPLER_2D_ARRAY:
-        case SamplerType::SAMPLER_EXTERNAL:
-        case SamplerType::SAMPLER_CUBEMAP:
-        case SamplerType::SAMPLER_CUBEMAP_ARRAY:
-            result = mDeviceLimits.maxTextureDimension2D;
-            break;
-        case SamplerType::SAMPLER_3D:
-            result = mDeviceLimits.maxTextureDimension3D;
-            break;
-    }
-    return result;
+    return 2048u;
 }

 size_t WebGPUDriver::getMaxArrayTextureLayers() {
-    return mDeviceLimits.maxTextureArrayLayers;
+    return 256u;
 }

 void WebGPUDriver::updateIndexBuffer(Handle<HwIndexBuffer> indexBufferHandle,
@@ -724,6 +692,27 @@ void WebGPUDriver::update3DImage(Handle<HwTexture> textureHandle, const uint32_t

    const uint8_t* dataBuff = static_cast<const uint8_t*>(data->buffer);
    size_t dataSize = data->size;
+    std::unique_ptr<uint8_t[]> paddedBuffer;
+
+    if (bytesPerRow % 256 != 0) {
+        uint32_t padding = 256 - (bytesPerRow % 256);
+        uint32_t paddedBytesPerRow = bytesPerRow + padding;
+
+        size_t paddedBufferSize = static_cast<size_t>(paddedBytesPerRow) * height * depth;
+        paddedBuffer = std::make_unique<uint8_t[]>(paddedBufferSize);
+        uint8_t* dest = paddedBuffer.get();
+
+        for (uint32_t z = 0; z < depth; ++z) {
+            for (uint32_t y = 0; y < height; ++y) {
+                std::memcpy(dest, dataBuff, bytesPerRow);
+                dest += paddedBytesPerRow;
+                dataBuff += bytesPerRow;
+            }
+        }
+        dataBuff = paddedBuffer.get();
+        dataSize = paddedBufferSize;
+        bytesPerRow = paddedBytesPerRow;
+    }

    auto layout = wgpu::TexelCopyBufferLayout{ .bytesPerRow = bytesPerRow, .rowsPerImage = height };

@@ -749,62 +738,66 @@ void WebGPUDriver::setExternalStream(Handle<HwTexture> textureHandle,
 }

 void WebGPUDriver::generateMipmaps(Handle<HwTexture> textureHandle) {
+    if (!mCommandEncoder) {
+        mMipQueue.push_back(textureHandle);
+        return;
+    }
    auto texture = handleCast<WebGPUTexture>(textureHandle);
    assert_invariant(texture);
    wgpu::Texture wgpuTexture = texture->getTexture();
    assert_invariant(wgpuTexture);

-    const uint32_t totalMipLevels = wgpuTexture.GetMipLevelCount();
-    if (totalMipLevels <= 1) {
-        return; // nothing to do
+    FILAMENT_CHECK_PRECONDITION(wgpuTexture.GetUsage() & wgpu::TextureUsage::CopySrc)
+            << "Texture intended for mipmap generation (as source) must have CopySrc usage.";
+    FILAMENT_CHECK_PRECONDITION(wgpuTexture.GetUsage() & wgpu::TextureUsage::CopyDst)
+            << "Texture intended for mipmap generation (as destination) must have CopyDst usage.";
+
+    uint32_t mipLevelCount = wgpuTexture.GetMipLevelCount();
+    if (mipLevelCount <= 1) {
+        return;
    }
+    FILAMENT_CHECK_PRECONDITION(texture->supportsMultipleMipLevels())
+            << "Calling generateMipmaps(...) on a texture that doesn't support generating them. "
+               "sampler type "
+            << to_string(texture->target) << " levels " << static_cast<uint32_t>(texture->levels)
+            << " wgpu format (enum value) "
+            << static_cast<uint32_t>(texture->getTexture().GetFormat()) << " width "
+            << texture->width << " height " << texture->height << " depth " << texture->depth
+            << " usage flags (as a number) " << static_cast<uint32_t>(texture->usage);

-    const auto usage = wgpuTexture.GetUsage();
-    FILAMENT_CHECK_PRECONDITION(usage & wgpu::TextureUsage::TextureBinding)
-            << "Texture for mipmap generation must have TextureBinding usage.";
+    uint32_t width = wgpuTexture.GetWidth();
+    uint32_t height = wgpuTexture.GetHeight();
+    // For 3D textures, depth is > 1. For 2D/Cube/Array, effectively 1 for mip-level copies.
+    uint32_t depth =
+            (texture->target == SamplerType::SAMPLER_3D) ? wgpuTexture.GetDepthOrArrayLayers() : 1;

-    switch (texture->getMipmapGenerationStrategy()) {
-        case WebGPUTexture::MipmapGenerationStrategy::RENDER_PASS:
-            FILAMENT_CHECK_PRECONDITION(usage & wgpu::TextureUsage::RenderAttachment)
-                    << "Texture for mipmap generation via render pass blit must have "
-                       "RenderAttachment usage.";
-            mRenderPassMipmapGenerator.generateMipmaps(mQueue, texture->getTexture());
-            break;
-        case WebGPUTexture::MipmapGenerationStrategy::NONE:
-            FWGPU_LOGW << "Trying to generate mipmaps for a texture we already know we cannot do "
-                          "such generation. Texture sample type "
-                       << to_string(texture->target) << " WebGPU texture format "
-                       << webGPUTextureFormatToString(texture->getViewFormat()) << " samples "
-                       << static_cast<uint32_t>(texture->samples)
-                       << ". Going to try using the SPD_COMPUTE_PASS approach.";
-            UTILS_FALLTHROUGH;
-        case WebGPUTexture::MipmapGenerationStrategy::SPD_COMPUTE_PASS:
-            FILAMENT_CHECK_PRECONDITION(usage & wgpu::TextureUsage::StorageBinding)
-                    << "Texture for mipmap generation must have StorageBinding usage "
-                       "(as a compute pass strategy was selected for use). "
-                       "supportsMultipleMipLevels for WebGPU texture format "
-                    << webGPUTextureFormatToString(wgpuTexture.GetFormat()) << " is "
-                    << WebGPUTexture::supportsMultipleMipLevelsViaStorageBinding(
-                               wgpuTexture.GetFormat());
-            // We will record all passes into a single command encoder.
-            wgpu::CommandEncoderDescriptor encoderDesc = {};
-            encoderDesc.label = "Mipmap Command Encoder";
-            wgpu::CommandEncoder encoder = mDevice.CreateCommandEncoder(&encoderDesc);
+    for (uint32_t mipLevel = 0; mipLevel < mipLevelCount - 1; ++mipLevel) {
+        wgpu::TexelCopyTextureInfo sourceCopyInfo{
+            .texture = wgpuTexture,
+            .mipLevel = mipLevel,
+            .aspect = texture->getAspect(),
+        };

-            spd::SPDPassConfig spdConfig = { .filter = spd::SPDFilter::Average,
-                .targetTexture = wgpuTexture,
-                .numMips = totalMipLevels,
-                .halfPrecision = false,
-                .sourceMipLevel = 0 };
+        wgpu::TexelCopyTextureInfo destinationCopyInfo{
+            .texture = wgpuTexture,
+            .mipLevel = mipLevel + 1,
+            .aspect = texture->getAspect(),
+        };

-            mSpdComputePassMipmapGenerator.Generate(encoder, wgpuTexture, spdConfig);
+        uint32_t dstWidth = std::max(1u, width >> 1);
+        uint32_t dstHeight = std::max(1u, height >> 1);
+        uint32_t dstDepth = std::max(1u, depth >> 1);

-            // Finish the encoder and submit all the passes at once.
-            wgpu::CommandBufferDescriptor cmdBufferDesc = {};
-            cmdBufferDesc.label = "Mipmap Command Buffer";
-            wgpu::CommandBuffer commandBuffer = encoder.Finish(&cmdBufferDesc);
-            mQueue.Submit(1, &commandBuffer);
-            break;
+        wgpu::Extent3D copySize{ .width = dstWidth,
+            .height = dstHeight,
+            .depthOrArrayLayers = (texture->target == SamplerType::SAMPLER_3D)
+                                          ? dstDepth
+                                          : texture->getArrayLayerCount() };
+        mCommandEncoder.CopyTextureToTexture(&sourceCopyInfo, &destinationCopyInfo, &copySize);
+
+        width = dstWidth;
+        height = dstHeight;
+        depth = dstDepth;
    }
 }

@@ -824,16 +817,12 @@ void WebGPUDriver::beginRenderPass(Handle<HwRenderTarget> renderTargetHandle,
    wgpu::TextureView defaultDepthStencilView = nullptr;
    wgpu::TextureFormat defaultDepthStencilFormat = wgpu::TextureFormat::Undefined;

-    const bool msaaSidecarsRequired{ renderTarget->getSamples() > 1 &&
-                                     renderTarget->getSampleCountPerAttachment() <= 1 };
-
    std::array<wgpu::TextureView, MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT> customColorViews{};
-    std::array<wgpu::TextureView, customColorViews.size()> customColorMsaaSidecarViews{};
    uint32_t customColorViewCount = 0;
-
-    wgpu::TextureView customDepthStencilView = nullptr;
-    wgpu::TextureView customDepthStencilMsaaSidecarTextureView = nullptr;
-    wgpu::TextureFormat customDepthStencilFormat = wgpu::TextureFormat::Undefined;
+    wgpu::TextureView customDepthView = nullptr;
+    wgpu::TextureFormat customDepthFormat = wgpu::TextureFormat::Undefined;
+    wgpu::TextureFormat customStencilFormat = wgpu::TextureFormat::Undefined;
+    wgpu::TextureView customStencilView = nullptr;

    mCurrentRenderTarget = renderTarget;
    if (renderTarget->isDefaultRenderTarget()) {
@@ -841,20 +830,6 @@ void WebGPUDriver::beginRenderPass(Handle<HwRenderTarget> renderTargetHandle,
        defaultColorView = mTextureView;
        defaultDepthStencilView = mSwapChain->getDepthTextureView();
        defaultDepthStencilFormat = mSwapChain->getDepthFormat();
-
-        if (any(renderTarget->getTargetFlags() & TargetBufferFlags::STENCIL) &&
-                !(hasStencil(defaultDepthStencilFormat))) {
-            FILAMENT_CHECK_POSTCONDITION(false)
-                    << "Default render target requested stencil, but swap chain's depth format "
-                    << (uint32_t) defaultDepthStencilFormat << " does not have a stencil aspect.";
-        }
-
-        if (any(renderTarget->getTargetFlags() & TargetBufferFlags::DEPTH) &&
-                !(hasDepth(defaultDepthStencilFormat))) {
-            FILAMENT_CHECK_POSTCONDITION(false)
-                    << "Default render target requested depth, but swap chain's depth format "
-                    << (uint32_t) defaultDepthStencilFormat << " does not have a depth aspect.";
-        }
    } else {
        // Resolve views for custom render target
        const auto& colorInfos = renderTarget->getColorAttachmentInfos();
@@ -869,78 +844,41 @@ void WebGPUDriver::beginRenderPass(Handle<HwRenderTarget> renderTargetHandle,
                            << ".";
                    const uint8_t mipLevel = colorInfos[i].level;
                    const uint32_t arrayLayer = colorInfos[i].layer;
-                    customColorViews[customColorViewCount] =
+                    customColorViews[customColorViewCount++] =
                            colorTexture->getOrMakeTextureView(mipLevel, arrayLayer);
-                    if (msaaSidecarsRequired) {
-                        const wgpu::TextureView msaaSidecarView{
-                            colorTexture->makeMsaaSidecarTextureViewIfTextureSidecarExists(
-                                    renderTarget->getSamples(), mipLevel, arrayLayer)
-                        };
-                        FILAMENT_CHECK_POSTCONDITION(msaaSidecarView)
-                                << "Could not get a required MSAA sidecar texture view for color "
-                                << customColorViewCount << "?";
-                        customColorMsaaSidecarViews[customColorViewCount] = msaaSidecarView;
-                    }
-                    customColorViewCount++;
                }
            }
        }
+
        const auto& depthInfo = renderTarget->getDepthAttachmentInfo();
-        const auto& stencilInfo = renderTarget->getStencilAttachmentInfo();
-
-        Handle<HwTexture> depthStencilSourceHandle = {};
-        uint8_t depthStencilMipLevel = 0;
-        uint32_t depthStencilArrayLayer = 0;
-
-        if (depthInfo.handle && stencilInfo.handle) {
-            auto const depthTexture{handleCast<WebGPUTexture>(depthInfo.handle)->getTexture()};
-            auto const stencilTexture{handleCast<WebGPUTexture>(stencilInfo.handle)->getTexture()};
-            FILAMENT_CHECK_POSTCONDITION(depthTexture.Get() == stencilTexture.Get())
-                    << "Filament must reference the same resource if both depth and stencil "
-                       "textures are present";
-        }
-
        if (depthInfo.handle) {
-            depthStencilSourceHandle = depthInfo.handle;
-            depthStencilMipLevel = depthInfo.level;
-            depthStencilArrayLayer = depthInfo.layer;
-        } else if (stencilInfo.handle) {
-            depthStencilSourceHandle = stencilInfo.handle;
-            depthStencilMipLevel = stencilInfo.level;
-            depthStencilArrayLayer = stencilInfo.layer;
+            FILAMENT_CHECK_POSTCONDITION(depthInfo.layer < renderTarget->getLayerCount())
+                    << "Depth attachment requests layer " << depthInfo.layer
+                    << "but render target has only " << renderTarget->getLayerCount() << ".";
+            auto depthTexture = handleCast<WebGPUTexture>(depthInfo.handle);
+            if (depthTexture) {
+                const uint8_t depthMipLevel = depthInfo.level;
+                const uint32_t depthArrayLayer = depthInfo.layer;
+                customDepthView =
+                        depthTexture->getOrMakeTextureView(depthMipLevel, depthArrayLayer);
+                customDepthFormat = depthTexture->getViewFormat();
+            }
        }

-        if (depthStencilSourceHandle) {
-            auto dsTexture = handleCast<WebGPUTexture>(depthStencilSourceHandle);
-            if (dsTexture) {
-                customDepthStencilView = dsTexture->getOrMakeTextureView(depthStencilMipLevel,
-                        depthStencilArrayLayer);
-                if (msaaSidecarsRequired) {
-                    customDepthStencilMsaaSidecarTextureView =
-                            dsTexture->makeMsaaSidecarTextureViewIfTextureSidecarExists(
-                                    renderTarget->getSamples(), depthStencilMipLevel,
-                                    depthStencilArrayLayer);
-                    FILAMENT_CHECK_POSTCONDITION(customDepthStencilMsaaSidecarTextureView)
-                            << "Could not get a required MSAA sidecar texture view for "
-                               "depth/stencil?";
-                }
-                customDepthStencilFormat = dsTexture->getViewFormat();
-
-                if (any(renderTarget->getTargetFlags() & TargetBufferFlags::STENCIL) &&
-                        !(hasStencil(customDepthStencilFormat))) {
-                    FILAMENT_CHECK_POSTCONDITION(false)
-                            << "Custom render target requested stencil, but the provided texture"
-                               "format number"
-                            << (uint32_t) customDepthStencilFormat
-                            << " does not have a stencil aspect.";
-                }
-                if (any(renderTarget->getTargetFlags() & TargetBufferFlags::DEPTH) &&
-                        !(hasDepth(customDepthStencilFormat))) {
-                    FILAMENT_CHECK_POSTCONDITION(false) << "Custom render target requested depth, "
-                                                           "but the provided texture format number"
-                                                        << (uint32_t) customDepthStencilFormat
-                                                        << " does not have a depth aspect.";
-                }
+        const auto& stencilInfo = renderTarget->getStencilAttachmentInfo();
+        if (stencilInfo.handle) {
+            // If depth and stencil use the same texture handle, this will re-cast but that's fine.
+            auto stencilTexture = handleCast<WebGPUTexture>(stencilInfo.handle);
+            if (stencilTexture) {
+                FILAMENT_CHECK_POSTCONDITION(stencilInfo.layer < renderTarget->getLayerCount())
+                        << "Stencil attachment requests layer " << stencilInfo.layer
+                        << " but render target has only " << renderTarget->getLayerCount()
+                        << " layers.";
+                const uint8_t stencilMipLevel = stencilInfo.level;
+                const uint32_t stencilArrayLayer = stencilInfo.layer;
+                customStencilView =
+                        stencilTexture->getOrMakeTextureView(stencilMipLevel, stencilArrayLayer);
+                customStencilFormat = stencilTexture->getViewFormat();
            }
        }
    }
@@ -949,11 +887,13 @@ void WebGPUDriver::beginRenderPass(Handle<HwRenderTarget> renderTargetHandle,
            params,
            defaultColorView,
            defaultDepthStencilView,
+            defaultDepthStencilFormat,
            customColorViews.data(),
-            customColorMsaaSidecarViews.data(),
            customColorViewCount,
-            customDepthStencilView,
-            customDepthStencilMsaaSidecarTextureView);
+            customDepthView,
+            customStencilView,
+            customDepthFormat,
+            customStencilFormat);

    mRenderPassEncoder = mCommandEncoder.BeginRenderPass(&renderPassDescriptor);

@@ -988,26 +928,16 @@ void WebGPUDriver::makeCurrent(Handle<HwSwapChain> drawSch, Handle<HwSwapChain>
    wgpu::Extent2D surfaceSize = mPlatform.getSurfaceExtent(mNativeWindow);
    mTextureView = mSwapChain->getCurrentSurfaceTextureView(surfaceSize);
    assert_invariant(mTextureView);
-
-    assert_invariant(mDefaultRenderTarget);
-
-    wgpu::TextureFormat depthFormat = mSwapChain->getDepthFormat();
-    TargetBufferFlags newTargetFlags = filament::backend::TargetBufferFlags::NONE;
-
-    //Assuming Color always present in default render target.
-    newTargetFlags |= filament::backend::TargetBufferFlags::COLOR;
-    if (depthFormat != wgpu::TextureFormat::Undefined) {
-        if (hasDepth(depthFormat)) {
-            newTargetFlags |= filament::backend::TargetBufferFlags::DEPTH;
-        }
-        if (hasStencil(depthFormat)) {
-            newTargetFlags |= filament::backend::TargetBufferFlags::STENCIL;
-        }
-    }
-    mDefaultRenderTarget->setTargetFlags(newTargetFlags);
-
-    wgpu::CommandEncoderDescriptor commandEncoderDescriptor = { .label = "frame_command_encoder" };
+    wgpu::CommandEncoderDescriptor commandEncoderDescriptor = {
+        .label = "command_encoder"
+    };
    mCommandEncoder = mDevice.CreateCommandEncoder(&commandEncoderDescriptor);
+    if (!mMipQueue.empty()) {
+        for (auto& handle: mMipQueue) {
+            generateMipmaps(handle);
+        }
+        mMipQueue.clear();
+    }
    assert_invariant(mCommandEncoder);
 }

@@ -1019,22 +949,6 @@ void WebGPUDriver::commit(Handle<HwSwapChain> sch) {
    assert_invariant(mCommandBuffer);
    mCommandEncoder = nullptr;
    mQueue.Submit(1, &mCommandBuffer);
-
-    static bool firstRender = true;
-    // For the first frame rendered, we need to make sure the work is done before presenting or we
-    // get a purple flash
-    if (firstRender) {
-        auto f = mQueue.OnSubmittedWorkDone(wgpu::CallbackMode::WaitAnyOnly,
-                [=](wgpu::QueueWorkDoneStatus) {});
-        const wgpu::Instance instance = mAdapter.GetInstance();
-        auto wStatus = instance.WaitAny(f,
-                std::chrono::duration_cast<std::chrono::nanoseconds>(1s).count());
-        if (wStatus != wgpu::WaitStatus::Success) {
-            FWGPU_LOGW << "Waiting for first frame work to finish resulted in an error"
-                       << static_cast<uint32_t>(wStatus);
-        }
-        firstRender = false;
-    }
    mCommandBuffer = nullptr;
    mTextureView = nullptr;
    assert_invariant(mSwapChain);
@@ -1087,33 +1001,7 @@ void WebGPUDriver::blitDEPRECATED(TargetBufferFlags buffers,
 void WebGPUDriver::resolve(Handle<HwTexture> destinationTextureHandle, const uint8_t sourceLevel,
        const uint8_t sourceLayer, Handle<HwTexture> sourceTextureHandle,
        const uint8_t destinationLevel, const uint8_t destinationLayer) {
-    FILAMENT_CHECK_PRECONDITION(mCommandEncoder)
-            << "Resolve assumes there is a valid command encoder to piggyback on.";
-    FILAMENT_CHECK_PRECONDITION(mRenderPassEncoder == nullptr)
-            << "Resolve cannot be called during an existing render pass";
-    const auto sourceTexture{ handleCast<WebGPUTexture>(sourceTextureHandle) };
-    const auto destinationTexture{ handleCast<WebGPUTexture>(destinationTextureHandle) };
-    assert_invariant(sourceTexture);
-    assert_invariant(destinationTexture);
-    const WebGPUMsaaTextureResolver::ResolveRequest request{
-        .commandEncoder = mCommandEncoder,
-        .viewFormat = sourceTexture->getViewFormat(),
-        .source = {
-            .texture = sourceTexture->getTexture(),
-            .viewDimension = sourceTexture->getViewDimension(),
-            .mipLevel = sourceLevel,
-            .layer = sourceLayer,
-            .aspect = sourceTexture->getAspect(),
-        },
-        .destination = {
-            .texture = destinationTexture->getTexture(),
-            .viewDimension = destinationTexture->getViewDimension(),
-            .mipLevel = destinationLevel,
-            .layer = destinationLayer,
-            .aspect = destinationTexture->getAspect(),
-        },
-    };
-    mMsaaTextureResolver.resolve(request);
+    // todo
 }

 void WebGPUDriver::blit(Handle<HwTexture> destinationTextureHandle, const uint8_t sourceLevel,
@@ -1123,24 +1011,13 @@ void WebGPUDriver::blit(Handle<HwTexture> destinationTextureHandle, const uint8_
    // todo
 }

-size_t WebGPUDriver::computePipelineKey(PipelineState const& pipelineState,
-        WebGPURenderTarget const* const renderTarget) const {
-    // TODO Investigate implications of this hash more closely. Vulkan has a whole class
-    //      VulkanPipelineCache to handle this, may be missing nuance
-    static const auto pipelineStateHasher{
-        utils::hash::MurmurHashFn<filament::backend::PipelineState>()
-    };
-    const std::hash<uint32_t> intHasher{};
-    const std::hash<WebGPURenderTarget const*> addressHasher{};
-    const size_t pipelineStateHash{ intHasher(pipelineStateHasher(pipelineState)) };
-    const size_t renderTargetHash{ addressHasher(renderTarget) };
-    return utils::hash::combine(pipelineStateHash, renderTargetHash);
-}
-
 void WebGPUDriver::bindPipeline(PipelineState const& pipelineState) {
-    auto pipelineKey{ computePipelineKey(pipelineState, mCurrentRenderTarget) };
-    if (mPipelineMap.find(pipelineKey) != mPipelineMap.end()) {
-        mRenderPassEncoder.SetPipeline(mPipelineMap[pipelineKey]);
+    // TODO Investigate implications of this hash more closely. Vulkan has a whole class
+    // VulkanPipelineCache to handle this, may be missing nuance
+    static auto pipleineStateHasher = utils::hash::MurmurHashFn<filament::backend::PipelineState>();
+    auto hash = pipleineStateHasher(pipelineState);
+    if (mPipelineMap.find(hash) != mPipelineMap.end()) {
+        mRenderPassEncoder.SetPipeline(mPipelineMap[hash]);
        return;
    }
    const auto program = handleCast<WebGPUProgram>(pipelineState.program);
@@ -1178,15 +1055,14 @@ void WebGPUDriver::bindPipeline(PipelineState const& pipelineState) {
    assert_invariant(vertexBufferInfo);

    std::vector<wgpu::TextureFormat> pipelineColorFormats;
-    wgpu::TextureFormat pipelineDepthStencilFormat = wgpu::TextureFormat::Undefined;
+    wgpu::TextureFormat pipelineDepthFormat = wgpu::TextureFormat::Undefined;
    uint8_t pipelineSamples = 1;
-    bool const requestedDepth = any(mCurrentRenderTarget->getTargetFlags() & TargetBufferFlags::DEPTH);
-    bool const requestedStencil = any(mCurrentRenderTarget->getTargetFlags() & TargetBufferFlags::STENCIL);
-    pipelineSamples = mCurrentRenderTarget->getSamples();

    if (mCurrentRenderTarget->isDefaultRenderTarget()) {
        pipelineColorFormats.push_back(mSwapChain->getColorFormat());
-        pipelineDepthStencilFormat = mSwapChain->getDepthFormat();
+        pipelineDepthFormat = mSwapChain->getDepthFormat();
+        pipelineSamples =
+                mCurrentRenderTarget->getSamples();// Default RT should have samples (usually 1)
    } else {
        const auto& mrtColorAttachments = mCurrentRenderTarget->getColorAttachmentInfos();
        for (size_t i = 0; i < MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT; ++i) {
@@ -1200,27 +1076,35 @@ void WebGPUDriver::bindPipeline(PipelineState const& pipelineState) {

        const auto& depthInfo = mCurrentRenderTarget->getDepthAttachmentInfo();
        const auto& stencilInfo = mCurrentRenderTarget->getStencilAttachmentInfo();
-        Handle<HwTexture> depthStencilHandle = {};
        if (depthInfo.handle) {
-            depthStencilHandle = depthInfo.handle;
-        } else if (stencilInfo.handle) {
-             depthStencilHandle = stencilInfo.handle;
-        }
-
-        if (depthStencilHandle) {
-            const auto dsTexture = handleCast<WebGPUTexture>(depthStencilHandle);
-            if (dsTexture) {
-                pipelineDepthStencilFormat = dsTexture->getTexture().GetFormat();
+            FILAMENT_CHECK_POSTCONDITION(!stencilInfo.handle)
+                    << "depth and stencil attachments cannot both be provided for WebGPU";
+            const auto depthTexture = handleCast<WebGPUTexture>(depthInfo.handle);
+            if (depthTexture) pipelineDepthFormat = depthTexture->getTexture().GetFormat();
+        } else {
+            if (stencilInfo.handle) {
+                const auto stencilTexture = handleCast<WebGPUTexture>(stencilInfo.handle);
+                // Assuming combined depth/stencil format if only stencil is present
+                if (stencilTexture) {
+                    pipelineDepthFormat = stencilTexture->getTexture().GetFormat();
+                }
            }
        }
+        pipelineSamples = mCurrentRenderTarget->getSamples();
    }

+    // TODO: We expected this to be a sane check, however it complains when running shadowtest.
+    //if (program->fragmentShaderModule != nullptr) {
+    //    FILAMENT_CHECK_POSTCONDITION(!pipelineColorFormats.empty())
+    //            << "Render pipeline with fragment shader must have at least one color target "
+    //               "format.";
+    //}
    wgpu::RenderPipeline pipeline = createWebGPURenderPipeline(mDevice, *program, *vertexBufferInfo,
            layout, pipelineState.rasterState, pipelineState.stencilState,
            pipelineState.polygonOffset, pipelineState.primitiveType, pipelineColorFormats,
-            pipelineDepthStencilFormat, pipelineSamples, requestedDepth, requestedStencil);
+            pipelineDepthFormat, pipelineSamples);
    assert_invariant(pipeline);
-    mPipelineMap[pipelineKey] = pipeline;
+    mPipelineMap[hash] = pipeline;
    mRenderPassEncoder.SetPipeline(pipeline);
 }

@@ -19,8 +19,6 @@

 #include "WebGPURenderTarget.h"
 #include "webgpu/WebGPUConstants.h"
-#include "webgpu/WebGPUMsaaTextureResolver.h"
-#include "webgpu/WebGPURenderPassMipmapGenerator.h"
 #include <backend/platforms/WebGPUPlatform.h>

 #include "DriverBase.h"
@@ -31,7 +29,6 @@

 #include <utils/compiler.h>

-#include "SpdMipmapGenerator/SpdMipmapGenerator.h"
 #include <tsl/robin_map.h>
 #include <webgpu/webgpu_cpp.h>

@@ -57,7 +54,7 @@ public:
    [[nodiscard]] static Driver* create(WebGPUPlatform& platform, const Platform::DriverConfig& driverConfig) noexcept;

 private:
-    WebGPUDriver(WebGPUPlatform& platform, const Platform::DriverConfig& driverConfig) noexcept;
+    explicit WebGPUDriver(WebGPUPlatform& platform, const Platform::DriverConfig& driverConfig) noexcept;
    [[nodiscard]] ShaderModel getShaderModel() const noexcept final;
    [[nodiscard]] ShaderLanguage getShaderLanguage() const noexcept final;
    [[nodiscard]] wgpu::Sampler makeSampler(SamplerParams const& params);
@@ -74,16 +71,14 @@ private:
    WebGPUSwapChain* mSwapChain = nullptr;
    uint64_t mNextFakeHandle = 1;
    wgpu::CommandEncoder mCommandEncoder = nullptr;
+    std::vector<Handle<HwTexture>> mMipQueue;
    wgpu::TextureView mTextureView = nullptr;
    wgpu::RenderPassEncoder mRenderPassEncoder = nullptr;
    wgpu::CommandBuffer mCommandBuffer = nullptr;
    WebGPURenderTarget* mDefaultRenderTarget = nullptr;
    WebGPURenderTarget* mCurrentRenderTarget = nullptr;
-    WebGPURenderPassMipmapGenerator mRenderPassMipmapGenerator;
-    spd::MipmapGenerator mSpdComputePassMipmapGenerator;
-    WebGPUMsaaTextureResolver mMsaaTextureResolver{};

-    tsl::robin_map<size_t, wgpu::RenderPipeline> mPipelineMap;
+    tsl::robin_map<uint32_t, wgpu::RenderPipeline> mPipelineMap;

    struct DescriptorSetBindingInfo{
        wgpu::BindGroup bindGroup;
@@ -91,9 +86,6 @@ private:
        backend::DescriptorSetOffsetArray offsets;
    };
    std::array<DescriptorSetBindingInfo,MAX_DESCRIPTOR_SET_COUNT> mCurrentDescriptorSets;
-
-    [[nodiscard]] size_t computePipelineKey(PipelineState const&, WebGPURenderTarget const*) const;
-
    /*
     * Driver interface
     */
@@ -128,11 +120,6 @@ private:
        return mHandleAllocator.construct<D>(handle, std::forward<ARGS>(args)...);
    }

-    template<typename D, typename B, typename... ARGS>
-    Handle<B> allocAndConstructHandle(ARGS&&... args) {
-        return mHandleAllocator.allocateAndConstruct<D>(std::forward<ARGS>(args)...);
-    }
-
    template<typename D, typename B>
    D* handleCast(Handle<B> handle) noexcept {
        return mHandleAllocator.handle_cast<D*>(handle);
@@ -1,50 +0,0 @@
-/*
- * 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 "WebGPUFence.h"
-
-#include <backend/DriverEnums.h>
-
-#include <webgpu/webgpu_cpp.h>
-
-#include <atomic>
-
-namespace filament::backend {
-
-FenceStatus WebGPUFence::getStatus() { return mStatus.load(); }
-
-void WebGPUFence::addMarkerToQueueState(wgpu::Queue const& queue) {
-    queue.OnSubmittedWorkDone(
-            wgpu::CallbackMode::AllowSpontaneous,
-            [](const wgpu::QueueWorkDoneStatus status,
-                    std::atomic<FenceStatus>* const fenceStatus) {
-                if (!fenceStatus) {
-                    return;
-                }
-                switch (status) {
-                    case wgpu::QueueWorkDoneStatus::Success:
-                        fenceStatus->store(FenceStatus::CONDITION_SATISFIED);
-                        break;
-                    case wgpu::QueueWorkDoneStatus::CallbackCancelled:
-                    case wgpu::QueueWorkDoneStatus::Error:
-                        fenceStatus->store(FenceStatus::ERROR);
-                        break;
-                }
-            },
-            &mStatus);
-}
-
-} // namespace filament::backend
@@ -1,43 +0,0 @@
-/*
- * 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 TNT_FILAMENT_BACKEND_WEBGPUFENCE_H
-#define TNT_FILAMENT_BACKEND_WEBGPUFENCE_H
-
-#include "DriverBase.h"
-#include <backend/DriverEnums.h>
-
-#include <atomic>
-
-namespace wgpu {
-class Queue;
-} // namespace wgpu
-
-namespace filament::backend {
-
-class WebGPUFence final : public HwFence {
-public:
-    [[nodiscard]] FenceStatus getStatus();
-
-    void addMarkerToQueueState(wgpu::Queue const&);
-
-private:
-    std::atomic<FenceStatus> mStatus{ FenceStatus::TIMEOUT_EXPIRED };
-};
-
-} // namespace filament::backend
-
-#endif // TNT_FILAMENT_BACKEND_WEBGPUFENCE_H
@@ -1,125 +0,0 @@
-/*
- * 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 "WebGPUMsaaTextureResolver.h"
-
-#include "WebGPUTexture.h"
-
-#include <utils/Panic.h>
-
-#include <webgpu/webgpu_cpp.h>
-
-namespace filament::backend {
-
-namespace {
-
-void resolveColorTextures(wgpu::CommandEncoder const& commandEncoder,
-        wgpu::TextureView const& sourceTextureView,
-        wgpu::TextureView const& destinationTextureView) {
-    const wgpu::RenderPassColorAttachment colorAttachment{
-        .view = sourceTextureView,
-        .depthSlice = wgpu::kDepthSliceUndefined, // being explicit for consistent behavior
-        .resolveTarget = destinationTextureView,
-        .loadOp = wgpu::LoadOp::Load,
-        .storeOp = wgpu::StoreOp::Store,
-        .clearValue = {}, // being explicit for consistent behavior
-    };
-    const wgpu::RenderPassDescriptor renderPassDescriptor{
-        .label = "resolve_render_pass",
-        .colorAttachmentCount = 1,
-        .colorAttachments = &colorAttachment,
-        .depthStencilAttachment = nullptr, // being explicit for consistent behavior
-        .occlusionQuerySet = nullptr,      // being explicit for consistent behavior
-        .timestampWrites = nullptr,        // being explicit for consistent behavior
-    };
-    const wgpu::RenderPassEncoder renderPassEncoder{ commandEncoder.BeginRenderPass(
-            &renderPassDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(renderPassEncoder)
-            << "Failed to create wgpu::RenderPassEncoder for WebGPUDriver::resolve";
-    renderPassEncoder.End(); // only the implicit resolve is happening in the pass
-}
-
-} // namespace
-
-void WebGPUMsaaTextureResolver::resolve(ResolveRequest const& request) {
-    ResolveRequest::TextureInfo const& source{ request.source };
-    ResolveRequest::TextureInfo const& destination{ request.destination };
-    FILAMENT_CHECK_PRECONDITION(destination.texture.GetWidth() == source.texture.GetWidth() &&
-                                destination.texture.GetHeight() == source.texture.GetHeight())
-            << "invalid resolve: source and destination sizes don't match";
-
-    FILAMENT_CHECK_PRECONDITION(
-            source.texture.GetSampleCount() > 1 && destination.texture.GetSampleCount() == 1)
-            << "invalid resolve: source.samples=" << source.texture.GetSampleCount()
-            << ", destination.samples=" << destination.texture.GetSampleCount();
-
-    FILAMENT_CHECK_PRECONDITION(source.texture.GetFormat() == destination.texture.GetFormat())
-            << "source and destination texture format don't match";
-    const wgpu::TextureFormat format{ source.texture.GetFormat() };
-
-    FILAMENT_CHECK_PRECONDITION(!hasDepth(format)) << "can't resolve depth formats";
-
-    FILAMENT_CHECK_PRECONDITION(!hasStencil(format)) << "can't resolve stencil formats";
-
-    FILAMENT_CHECK_PRECONDITION(source.texture.GetUsage() & wgpu::TextureUsage::RenderAttachment)
-            << "source texture usage doesn't have wgpu::TextureUsage::RenderAttachment";
-
-    FILAMENT_CHECK_PRECONDITION(
-            destination.texture.GetUsage() & wgpu::TextureUsage::RenderAttachment)
-            << "destination texture usage doesn't have wgpu::TextureUsage::RenderAttachment";
-
-    FILAMENT_CHECK_PRECONDITION(destination.texture.GetUsage() & wgpu::TextureUsage::TextureBinding)
-            << "destination texture usage doesn't have wgpu::TextureUsage::TextureBinding";
-
-    const wgpu::TextureViewDescriptor sourceTextureViewDescriptor{
-        .label = "resolve_source_texture_view",
-        .format = request.viewFormat,
-        .dimension = source.viewDimension,
-        .baseMipLevel = source.mipLevel,
-        .mipLevelCount = 1,
-        .baseArrayLayer = source.layer,
-        .arrayLayerCount = 1,
-        .aspect = source.aspect,
-        .usage = source.texture.GetUsage(),
-    };
-    const wgpu::TextureView sourceTextureView{ source.texture.CreateView(
-            &sourceTextureViewDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(sourceTextureView)
-            << "Failed to create wgpu::TextureView sourceTextureView";
-    const wgpu::TextureViewDescriptor destinationTextureViewDescriptor{
-        .label = "resolve_destination_texture_view",
-        .format = request.viewFormat,
-        .dimension = destination.viewDimension,
-        .baseMipLevel = destination.mipLevel,
-        .mipLevelCount = 1,
-        .baseArrayLayer = destination.layer,
-        .arrayLayerCount = 1,
-        .aspect = destination.aspect,
-        .usage = destination.texture.GetUsage(),
-    };
-    const wgpu::TextureView destinationTextureView{ destination.texture.CreateView(
-            &destinationTextureViewDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(destinationTextureView)
-            << "Failed to create wgpu::TextureView destinationTextureView.";
-
-    if (hasDepth(format)) {
-        PANIC_PRECONDITION("DEPTH RESOLVE NOT IMPLEMENTED YET");
-    } else {
-        resolveColorTextures(request.commandEncoder, sourceTextureView, destinationTextureView);
-    }
-}
-
-} // namespace filament::backend
@@ -1,55 +0,0 @@
-/*
- * 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 TNT_FILAMENT_BACKEND_WEBGPUMSAATEXTURERESOLVER_H
-#define TNT_FILAMENT_BACKEND_WEBGPUMSAATEXTURERESOLVER_H
-
-#include <cstdint>
-
-namespace wgpu {
-class CommandEncoder;
-class Texture;
-enum class TextureAspect : uint32_t;
-enum class TextureFormat : uint32_t;
-enum class TextureViewDimension : uint32_t;
-} // namespace wgpu
-
-namespace filament::backend {
-
-class WebGPUTexture;
-
-class WebGPUMsaaTextureResolver final {
-public:
-    struct ResolveRequest final {
-        struct TextureInfo final {
-            wgpu::Texture const& texture;
-            wgpu::TextureViewDimension viewDimension;
-            uint8_t mipLevel;
-            uint8_t layer;
-            wgpu::TextureAspect aspect;
-        };
-        wgpu::CommandEncoder const& commandEncoder;
-        wgpu::TextureFormat viewFormat;
-        TextureInfo source;
-        TextureInfo destination;
-    };
-
-    void resolve(ResolveRequest const&);
-};
-
-} // namespace filament::backend
-
-#endif // TNT_FILAMENT_BACKEND_WEBGPUMSAATEXTURERESOLVER_H
@@ -169,52 +169,39 @@ wgpu::RenderPipeline createWebGPURenderPipeline(wgpu::Device const& device,
        wgpu::PipelineLayout const& layout, RasterState const& rasterState,
        StencilState const& stencilState, PolygonOffset const& polygonOffset,
        const PrimitiveType primitiveType, std::vector<wgpu::TextureFormat> const& colorFormats,
-        wgpu::TextureFormat const& depthStencilFormat, const uint8_t samplesCount, const bool requestedDepth, const bool requestedStencil) {
+        const wgpu::TextureFormat depthFormat, const uint8_t samplesCount) {
    assert_invariant(program.vertexShaderModule);
    wgpu::DepthStencilState depthStencilState{};
-    const bool depthOrStencilRequested = (requestedDepth || requestedStencil);
+    if (depthFormat != wgpu::TextureFormat::Undefined) {
+        depthStencilState.format = depthFormat;
+        depthStencilState.depthWriteEnabled = rasterState.depthWrite;
+        depthStencilState.depthCompare = toWebGPU(rasterState.depthFunc);
+        depthStencilState.stencilFront = {
+            .compare = toWebGPU(stencilState.front.stencilFunc),
+            .failOp = toWebGPU(stencilState.front.stencilOpStencilFail),
+            .depthFailOp = toWebGPU(stencilState.front.stencilOpDepthFail),
+            .passOp = toWebGPU(stencilState.front.stencilOpDepthStencilPass),
+        };
+        depthStencilState.stencilBack = {
+            .compare = toWebGPU(stencilState.back.stencilFunc),
+            .failOp = toWebGPU(stencilState.back.stencilOpStencilFail),
+            .depthFailOp = toWebGPU(stencilState.back.stencilOpDepthFail),
+            .passOp = toWebGPU(stencilState.back.stencilOpDepthStencilPass),
+        };
+        depthStencilState.stencilReadMask =
+                stencilState.front.readMask; // Use front face's comparison mask for read mask
+        depthStencilState.stencilWriteMask = stencilState.stencilWrite ? 0xFFFFFFFF : 0u;
+        depthStencilState.depthBias = static_cast<int32_t>(polygonOffset.constant);
+        depthStencilState.depthBiasSlopeScale = polygonOffset.slope;
+        depthStencilState.depthBiasClamp = 0.0f;

-    if (depthOrStencilRequested) {
-        FILAMENT_CHECK_PRECONDITION(depthStencilFormat != wgpu::TextureFormat::Undefined)
-                << "Depth or Stencil requested for pipeline, but depthStencilFormat is "
-                   "wgpu::TextureFormat::Undefined.";
-        depthStencilState.format = depthStencilFormat;
-
-        if (requestedDepth) {
-            depthStencilState.depthWriteEnabled = rasterState.depthWrite;
-            depthStencilState.depthCompare = toWebGPU(rasterState.depthFunc);
-             depthStencilState.depthBias = static_cast<int32_t>(polygonOffset.constant);
-             depthStencilState.depthBiasSlopeScale = polygonOffset.slope;
-             depthStencilState.depthBiasClamp = 0.0f;
-        } else {
-            depthStencilState.depthWriteEnabled = false;
-            depthStencilState.depthCompare = wgpu::CompareFunction::Undefined;
-            depthStencilState.depthBias = 0;
-            depthStencilState.depthBiasSlopeScale = 0.0f;
-            depthStencilState.depthBiasClamp = 0.0f;
-        }
-
-        if (hasStencilAspect(depthStencilFormat) && requestedStencil) {
-            depthStencilState.stencilFront = {
-                .compare = toWebGPU(stencilState.front.stencilFunc),
-                .failOp = toWebGPU(stencilState.front.stencilOpStencilFail),
-                .depthFailOp = toWebGPU(stencilState.front.stencilOpDepthFail),
-                .passOp = toWebGPU(stencilState.front.stencilOpDepthStencilPass),
-            };
-            depthStencilState.stencilBack = {
-                .compare = toWebGPU(stencilState.back.stencilFunc),
-                .failOp = toWebGPU(stencilState.back.stencilOpStencilFail),
-                .depthFailOp = toWebGPU(stencilState.back.stencilOpDepthFail),
-                .passOp = toWebGPU(stencilState.back.stencilOpDepthStencilPass),
-            };
-            depthStencilState.stencilReadMask = stencilState.front.readMask;
-            depthStencilState.stencilWriteMask = stencilState.stencilWrite ? stencilState.front.writeMask : 0u;
-        } else {
-            depthStencilState.stencilFront.compare = wgpu::CompareFunction::Undefined;
+        if (!hasStencilAspect(depthFormat)) {
+            depthStencilState.stencilFront.compare = wgpu::CompareFunction::Always;
            depthStencilState.stencilFront.failOp = wgpu::StencilOperation::Keep;
            depthStencilState.stencilFront.depthFailOp = wgpu::StencilOperation::Keep;
            depthStencilState.stencilFront.passOp = wgpu::StencilOperation::Keep;
-            depthStencilState.stencilBack = depthStencilState.stencilFront;
+            depthStencilState.stencilBack =
+                    depthStencilState.stencilFront; // Keep back and front consistent
            depthStencilState.stencilReadMask = 0;
            depthStencilState.stencilWriteMask = 0;
        }
@@ -258,11 +245,11 @@ wgpu::RenderPipeline createWebGPURenderPipeline(wgpu::Device const& device,
            .unclippedDepth = !rasterState.depthClamp &&
                              device.HasFeature(wgpu::FeatureName::DepthClipControl)
        },
-        .depthStencil = depthOrStencilRequested ? &depthStencilState: nullptr,
+        .depthStencil = depthFormat != wgpu::TextureFormat::Undefined ? &depthStencilState: nullptr,
        .multisample = {
            .count = samplesCount,
            .mask = 0xFFFFFFFF,
-            .alphaToCoverageEnabled = (samplesCount > 1) && rasterState.alphaToCoverage
+            .alphaToCoverageEnabled = rasterState.alphaToCoverage
        },
        .fragment = nullptr // will add below if fragment module is included
    };
@@ -281,32 +268,27 @@ wgpu::RenderPipeline createWebGPURenderPipeline(wgpu::Device const& device,
        }
    };
    if (program.fragmentShaderModule != nullptr) {
-        // According to the WebGPU spec, a pipeline cannot have a fragment stage with zero color
-        // targets. This situation can arise in Filament during depth-only passes (like shadow map
-        // generation) if the material variant still includes a fragment shader.
-        //
-        // To handle this, we check if any color targets are configured for this pipeline. If not, we
-        // create a pipeline *without* a fragment stage. This makes the pipeline valid for a
-        // depth-only pass, allowing depth writes to proceed correctly.
-        if (!colorFormats.empty()) {
-            fragmentState.module = program.fragmentShaderModule;
-            fragmentState.entryPoint = "main";
-            // see the comment about constants for the vertex state, as the same reasoning applies
-            // here
-            fragmentState.constantCount = 0,
-            fragmentState.constants = nullptr,
-            fragmentState.targetCount = colorFormats.size();
-            fragmentState.targets = colorTargets.data();
-            assert_invariant(fragmentState.targetCount <= MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT);
-            for (size_t targetIndex = 0; targetIndex < fragmentState.targetCount; targetIndex++) {
-                auto& colorTarget = colorTargets[targetIndex];
-                colorTarget.format = colorFormats[targetIndex];
-                colorTarget.blend = rasterState.hasBlending() ? &blendState : nullptr;
-                colorTarget.writeMask =
-                        rasterState.colorWrite ? wgpu::ColorWriteMask::All : wgpu::ColorWriteMask::None;
-            }
-            pipelineDescriptor.fragment = &fragmentState;
+        fragmentState.module = program.fragmentShaderModule;
+        fragmentState.entryPoint = "main";
+        // see the comment about constants for the vertex state, as the same reasoning applies
+        // here
+        fragmentState.constantCount = 0,
+        fragmentState.constants = nullptr,
+        fragmentState.targetCount = colorFormats.size();
+        fragmentState.targets = colorTargets.data();
+        assert_invariant(fragmentState.targetCount <= MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT);
+        // We expect a fragment shader implies at least one color target if it outputs color.
+        // This should be guaranteed by the caller ensuring colorFormats is not empty.
+        // However, this fails on shadowtest.cpp, TODO investigate why
+        // assert_invariant(fragmentState.targetCount > 0);
+        for (size_t targetIndex = 0; targetIndex < fragmentState.targetCount; targetIndex++) {
+            auto& colorTarget = colorTargets[targetIndex];
+            colorTarget.format = colorFormats[targetIndex];
+            colorTarget.blend = rasterState.hasBlending() ? &blendState : nullptr;
+            colorTarget.writeMask =
+                    rasterState.colorWrite ? wgpu::ColorWriteMask::All : wgpu::ColorWriteMask::None;
        }
+        pipelineDescriptor.fragment = &fragmentState;
    }
    const wgpu::RenderPipeline pipeline = device.CreateRenderPipeline(&pipelineDescriptor);
    FILAMENT_CHECK_POSTCONDITION(pipeline)
@@ -40,8 +40,8 @@ class WebGPUProgram;
 [[nodiscard]] wgpu::RenderPipeline createWebGPURenderPipeline(wgpu::Device const&,
        WebGPUProgram const&, WebGPUVertexBufferInfo const&, wgpu::PipelineLayout const&,
        RasterState const&, StencilState const&, PolygonOffset const&, PrimitiveType primitiveType,
-        std::vector<wgpu::TextureFormat> const& colorFormats, wgpu::TextureFormat const& depthStencilFormat,
-        uint8_t samplesCount, bool requestedDepth, bool requestedStencil);
+        std::vector<wgpu::TextureFormat> const& colorFormats, wgpu::TextureFormat depthFormat,
+        uint8_t samplesCount);

 }// namespace filament::backend

@@ -1,552 +0,0 @@
-/*
- * 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 "WebGPURenderPassMipmapGenerator.h"
-
-#include <utils/Panic.h>
-
-#include <webgpu/webgpu_cpp.h>
-
-#include <cstdint>
-#include <string_view>
-
-namespace filament::backend {
-
-namespace {
-
-// The shaders expect a single-sampled 2D texture
-// with a format compatible with scalar sample format f32
-// (this is checked with the getCompatibilityFor function)
-constexpr uint32_t TEXTURE_BIND_GROUP_INDEX{ 0 };
-constexpr size_t TEXTURE_BIND_GROUP_ENTRY_SIZE{ 2 }; // sampler and texture
-constexpr uint32_t SAMPLER_BINDING_INDEX{ 0 };
-constexpr uint32_t TEXTURE_BINDING_INDEX{ 1 };
-constexpr std::string_view VERTEX_SHADER_ENTRY_POINT{ "vertexShaderMain" };
-constexpr std::string_view FRAGMENT_SHADER_ENTRY_POINT{ "fragmentShaderMain" };
-// Note: would be nice to generate this constexpr string from the constexpr variables above
-// to avoid them getting out of sync while still having the compile/build time optimization
-constexpr std::string_view SHADER_SOURCE{ R"(
-    @group(0) @binding(0) var previousMipLevelSampler: sampler;
-    @group(0) @binding(1) var previousMipLevelTexture: texture_2d<f32>;
-
-    struct VertexShaderOutput {
-      @builtin(position) position: vec4<f32>,
-      @location(0) textureCoordinate: vec2<f32>,
-    };
-
-    @vertex
-    fn vertexShaderMain(@builtin(vertex_index) vertexIndex: u32) -> VertexShaderOutput {
-        let fullScreenTriangleVertices = array<vec2<f32>, 3>(
-            vec2<f32>(-1.0, -1.0),
-            vec2<f32>(3.0, -1.0),
-            vec2<f32>(-1.0, 3.0)
-        );
-        var out: VertexShaderOutput;
-        let vertex = fullScreenTriangleVertices[vertexIndex];
-        out.position = vec4<f32>(vertex * 2.0 - 1.0, 0.0, 1.0);
-        out.textureCoordinate = vec2<f32>(vertex.x, 1.0 - vertex.y);
-        return out;
-    }
-
-    @fragment
-    fn fragmentShaderMain(in: VertexShaderOutput) -> @location(0) vec4<f32> {
-        return textureSample(previousMipLevelTexture,
-                             previousMipLevelSampler,
-                             in.textureCoordinate);
-    }
-)" };
-
-[[nodiscard]] wgpu::Sampler createPreviousMipLevelSampler(wgpu::Device const& device) {
-    const wgpu::SamplerDescriptor descriptor{
-        .label = "previous_mip_level_sampler",
-        .addressModeU = wgpu::AddressMode::ClampToEdge,
-        .addressModeV = wgpu::AddressMode::ClampToEdge,
-        .addressModeW = wgpu::AddressMode::Undefined, // only 2D textures supported for now
-        .magFilter = wgpu::FilterMode::Linear,
-        .minFilter = wgpu::FilterMode::Linear,
-        .mipmapFilter = wgpu::MipmapFilterMode::Nearest, // unused for this purpose
-        .lodMinClamp = 0.0f,  // should not matter, just being consistently defined
-        .lodMaxClamp = 32.0f, // should not matter, just being consistently defined
-        .compare = wgpu::CompareFunction::Undefined, // should not matter, just being consistently
-                                                     // defined
-        .maxAnisotropy = 1, // should not matter, just being consistently defined
-    };
-    const wgpu::Sampler sampler{ device.CreateSampler(&descriptor) };
-    FILAMENT_CHECK_POSTCONDITION(sampler) << "Failed to create previous mip level sampler?";
-    return sampler;
-}
-
-[[nodiscard]] wgpu::ShaderModule createShaderModule(wgpu::Device const& device) {
-    wgpu::ShaderModuleWGSLDescriptor wgslDescriptor{};
-    wgslDescriptor.code = SHADER_SOURCE.data();
-    const wgpu::ShaderModuleDescriptor shaderModuleDescriptor{
-        .nextInChain = &wgslDescriptor,
-        .label = "render_pass_mipmap_generation_shaders",
-    };
-    const wgpu::ShaderModule shaderModule{ device.CreateShaderModule(&shaderModuleDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(shaderModule)
-            << "Failed to create shader module for render pass mipmap generation?";
-    return shaderModule;
-}
-
-[[nodiscard]] wgpu::BindGroupLayout createTextureBindGroupLayout(wgpu::Device const& device) {
-    const wgpu::BindGroupLayoutEntry bindGroupLayoutEntries[TEXTURE_BIND_GROUP_ENTRY_SIZE] {
-        {
-            .binding = SAMPLER_BINDING_INDEX,
-            .visibility = wgpu::ShaderStage::Fragment,
-            .sampler = {
-                .type = wgpu::SamplerBindingType::Filtering, // only hardware accelerated filtering
-                                                             // supported
-            },
-        },
-        {
-            .binding = TEXTURE_BINDING_INDEX,
-            .visibility = wgpu::ShaderStage::Fragment,
-            .texture = {
-                .sampleType = wgpu::TextureSampleType::Float, // only F32 scalar sample
-                                                              // type supported for now
-                .viewDimension = wgpu::TextureViewDimension::e2D, // only 2D supported for now
-                .multisampled = false, // MSAA textures not supported for now
-            },
-        },
-    };
-    const wgpu::BindGroupLayoutDescriptor textureBindGroupLayoutDescriptor{
-        .label = "render_pass_mipmap_generation_texture_bind_group_layout",
-        .entryCount = TEXTURE_BIND_GROUP_ENTRY_SIZE,
-        .entries = bindGroupLayoutEntries,
-    };
-    const wgpu::BindGroupLayout textureBindGroupLayout{ device.CreateBindGroupLayout(
-            &textureBindGroupLayoutDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(textureBindGroupLayout)
-            << "Failed to create texture bind group layout for render pass mipmap generation?";
-    return textureBindGroupLayout;
-}
-
-[[nodiscard]] wgpu::PipelineLayout createPipelineLayout(wgpu::Device const& device,
-        wgpu::BindGroupLayout const& textureBindGroupLayout) {
-    const wgpu::PipelineLayoutDescriptor pipelineLayoutDescriptor{
-        .label = "render_pass_mipmap_generation_pipeline_layout",
-        .bindGroupLayoutCount = 1,
-        .bindGroupLayouts = &textureBindGroupLayout,
-    };
-    const wgpu::PipelineLayout pipelineLayout{ device.CreatePipelineLayout(
-            &pipelineLayoutDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(pipelineLayout)
-            << "Failed to create pipeline layout for render pass mipmap generation?";
-    return pipelineLayout;
-}
-
-[[nodiscard]] wgpu::RenderPipeline createPipeline(wgpu::Device const& device,
-        wgpu::ShaderModule const& shaderModule, wgpu::PipelineLayout const& pipelineLayout,
-        const wgpu::TextureFormat textureFormat) {
-    const wgpu::ColorTargetState colorTargetState{ .format = textureFormat };
-    const wgpu::FragmentState fragmentState{
-        .module = shaderModule,
-        .entryPoint = FRAGMENT_SHADER_ENTRY_POINT,
-        .constantCount = 0,   // should not matter, just being consistently defined
-        .constants = nullptr, // should not matter, just being consistently defined
-        .targetCount = 1,
-        .targets = &colorTargetState,
-    };
-    const wgpu::RenderPipelineDescriptor pipelineDescriptor{
-        .label = "render_pass_mipmap_generation_pipeline",
-        .layout = pipelineLayout,
-        .vertex = {
-            .module = shaderModule,
-            .entryPoint = VERTEX_SHADER_ENTRY_POINT,
-            .constantCount = 0, // should not matter, just being consistently defined
-            .constants = nullptr, // should not matter, just being consistently defined
-            .bufferCount = 0, // using hardcoded vertices in the shader for
-                              // performance and simplicity
-            .buffers = nullptr,
-        },
-        .primitive = {
-            .topology = wgpu::PrimitiveTopology::TriangleList,
-            .stripIndexFormat = wgpu::IndexFormat::Undefined, // should not matter
-                                                              // (not using a strip topology),
-                                                              // just being consistently defined
-            .frontFace = wgpu::FrontFace::Undefined, // should not matter (no cull mode),
-                                                     // just being consistently defined
-            .cullMode = wgpu::CullMode::None,
-            .unclippedDepth = false, // should not matter, just being consistently defined
-        },
-        .depthStencil = nullptr, // not applicable, but explicitly set here for
-                                 // consistent definition
-        .multisample = {
-            .count = 1, // no multi-sampling
-            .mask = 0xFFFFFFFF,
-            .alphaToCoverageEnabled = false,
-        },
-        .fragment = &fragmentState,
-    };
-    const wgpu::RenderPipeline pipeline{ device.CreateRenderPipeline(&pipelineDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(pipeline)
-            << "Failed to create pipeline for render pass mipmap generation?";
-    return pipeline;
-}
-
-} // namespace
-
-WebGPURenderPassMipmapGenerator::WebGPURenderPassMipmapGenerator(wgpu::Device const& device)
-    : mDevice{ device },
-      mPreviousMipLevelSampler{ createPreviousMipLevelSampler(mDevice) },
-      mShaderModule{ createShaderModule(mDevice) },
-      mTextureBindGroupLayout{ createTextureBindGroupLayout(mDevice) },
-      mPipelineLayout{ createPipelineLayout(mDevice, mTextureBindGroupLayout) } {}
-
-WebGPURenderPassMipmapGenerator::FormatCompatibility
-WebGPURenderPassMipmapGenerator::getCompatibilityFor(const wgpu::TextureFormat format,
-        const wgpu::TextureDimension dimension, const uint32_t sampleCount) {
-    // check that the format is compatible (currently expects that the scalar sample type is
-    // f32)...
-    switch (format) {
-        case wgpu::TextureFormat::Depth16Unorm:
-        case wgpu::TextureFormat::Depth24Plus:
-        case wgpu::TextureFormat::Depth24PlusStencil8:
-        case wgpu::TextureFormat::Depth32Float:
-        case wgpu::TextureFormat::Depth32FloatStencil8:
-            return {
-                .compatible = false,
-                .reason = "A depth texture format requires special sampler treatment and does "
-                          "not "
-                          "generally support linear filtering needed for render pass based "
-                          "mipmap "
-                          "generation, thus this texture is not supported, as it is a kind of "
-                          "depth texture.",
-            };
-        case wgpu::TextureFormat::Undefined:
-        case wgpu::TextureFormat::External:
-            return {
-                .compatible = false,
-                .reason = "Undefined or External textures are not supported for render pass "
-                          "based "
-                          "mipmap generation",
-            };
-        default:
-            const ScalarSampleType scalarSampleType{ getScalarSampleTypeFrom(format) };
-            switch (scalarSampleType) {
-                case ScalarSampleType::U32:
-                    return {
-                        .compatible = false,
-                        .reason = "The provided texture format requires an unsigned integer "
-                                  "sampler, which does not natively support linear filtering, "
-                                  "which is needed for render pass based mipmap generation.",
-                    };
-                case ScalarSampleType::I32:
-                    return {
-                        .compatible = false,
-                        .reason = "The provided texture format requires a signed integer "
-                                  "sampler, which does not natively support linear filtering, "
-                                  "which is needed for render pass based mipmap generation.",
-                    };
-                case ScalarSampleType::F32:
-                    break;
-            }
-    }
-    // check that the dimensionality is compatible (currently expects 2D textures)...
-    switch (dimension) {
-        case wgpu::TextureDimension::Undefined:
-            return {
-                .compatible = false,
-                .reason = "Texture has an undefined texture dimension (expected 2D), thus it is "
-                          "not "
-                          "supported by the render pass based mipmap generation implementation.",
-            };
-        case wgpu::TextureDimension::e1D:
-            return {
-                .compatible = false,
-                .reason = "Texture has a 1D texture dimension (expected 2D), thus it is not "
-                          "current supported by the render pass based mipmap generation "
-                          "implementation (but could be extended to later if needed).",
-            };
-        case wgpu::TextureDimension::e3D:
-            return {
-                .compatible = false,
-                .reason = "Texture has a 3D texture dimension (expected 2D), thus it is not "
-                          "current supported by the render pass based mipmap generation "
-                          "implementation (but could be extended to later if REALLY needed).",
-            };
-        case wgpu::TextureDimension::e2D:
-            break;
-    }
-    // check that the texture is single-sampled (for now)...
-    if (sampleCount > 1) {
-        return {
-            .compatible = false,
-            .reason = "Multi-sampled textures are not currently supported with the render pass "
-                      "based mipmap generation implementation (but could be extended to later if "
-                      "REALLY needed. The idea would be to resolve the texture to a single "
-                      "sampled "
-                      "texture before generating single-sample mipmaps, but that may still not "
-                      "necessarily be what is desired.).",
-        };
-    }
-    return { .compatible = true, .reason = "" };
-}
-
-constexpr WebGPURenderPassMipmapGenerator::ScalarSampleType
-WebGPURenderPassMipmapGenerator::getScalarSampleTypeFrom(const wgpu::TextureFormat format) {
-    switch (format) {
-        case wgpu::TextureFormat::R8Uint:
-        case wgpu::TextureFormat::R16Uint:
-        case wgpu::TextureFormat::R32Uint:
-        case wgpu::TextureFormat::Stencil8:
-        case wgpu::TextureFormat::RG8Uint:
-        case wgpu::TextureFormat::RG16Uint:
-        case wgpu::TextureFormat::RGBA8Uint:
-        case wgpu::TextureFormat::RGB10A2Uint:
-        case wgpu::TextureFormat::RG32Uint:
-        case wgpu::TextureFormat::RGBA16Uint:
-        case wgpu::TextureFormat::RGBA32Uint:
-            return ScalarSampleType::U32;
-        case wgpu::TextureFormat::R8Sint:
-        case wgpu::TextureFormat::R16Sint:
-        case wgpu::TextureFormat::R32Sint:
-        case wgpu::TextureFormat::RG8Sint:
-        case wgpu::TextureFormat::RG16Sint:
-        case wgpu::TextureFormat::RGBA8Sint:
-        case wgpu::TextureFormat::RG32Sint:
-        case wgpu::TextureFormat::RGBA16Sint:
-        case wgpu::TextureFormat::RGBA32Sint:
-            return ScalarSampleType::I32;
-        case wgpu::TextureFormat::R8Snorm:
-        case wgpu::TextureFormat::R8Unorm:
-        case wgpu::TextureFormat::R16Float:
-        case wgpu::TextureFormat::RG16Float:
-        case wgpu::TextureFormat::RG8Unorm:
-        case wgpu::TextureFormat::RG8Snorm:
-        case wgpu::TextureFormat::R32Float:
-        case wgpu::TextureFormat::RGBA8Unorm:
-        case wgpu::TextureFormat::RGBA8UnormSrgb:
-        case wgpu::TextureFormat::RGBA8Snorm:
-        case wgpu::TextureFormat::BGRA8Unorm:
-        case wgpu::TextureFormat::BGRA8UnormSrgb:
-        case wgpu::TextureFormat::RGB10A2Unorm:
-        case wgpu::TextureFormat::RG11B10Ufloat:
-        case wgpu::TextureFormat::RGB9E5Ufloat:
-        case wgpu::TextureFormat::RG32Float:
-        case wgpu::TextureFormat::RGBA16Float:
-        case wgpu::TextureFormat::RGBA32Float:
-        case wgpu::TextureFormat::BC1RGBAUnorm:
-        case wgpu::TextureFormat::BC1RGBAUnormSrgb:
-        case wgpu::TextureFormat::BC2RGBAUnorm:
-        case wgpu::TextureFormat::BC2RGBAUnormSrgb:
-        case wgpu::TextureFormat::BC3RGBAUnorm:
-        case wgpu::TextureFormat::BC3RGBAUnormSrgb:
-        case wgpu::TextureFormat::BC4RUnorm:
-        case wgpu::TextureFormat::BC4RSnorm:
-        case wgpu::TextureFormat::BC5RGUnorm:
-        case wgpu::TextureFormat::BC5RGSnorm:
-        case wgpu::TextureFormat::BC6HRGBUfloat:
-        case wgpu::TextureFormat::BC6HRGBFloat:
-        case wgpu::TextureFormat::BC7RGBAUnorm:
-        case wgpu::TextureFormat::BC7RGBAUnormSrgb:
-        case wgpu::TextureFormat::ETC2RGB8Unorm:
-        case wgpu::TextureFormat::ETC2RGB8UnormSrgb:
-        case wgpu::TextureFormat::ETC2RGB8A1Unorm:
-        case wgpu::TextureFormat::ETC2RGB8A1UnormSrgb:
-        case wgpu::TextureFormat::ETC2RGBA8Unorm:
-        case wgpu::TextureFormat::ETC2RGBA8UnormSrgb:
-        case wgpu::TextureFormat::EACR11Unorm:
-        case wgpu::TextureFormat::EACR11Snorm:
-        case wgpu::TextureFormat::EACRG11Unorm:
-        case wgpu::TextureFormat::EACRG11Snorm:
-        case wgpu::TextureFormat::ASTC4x4Unorm:
-        case wgpu::TextureFormat::ASTC4x4UnormSrgb:
-        case wgpu::TextureFormat::ASTC5x4Unorm:
-        case wgpu::TextureFormat::ASTC5x4UnormSrgb:
-        case wgpu::TextureFormat::ASTC5x5Unorm:
-        case wgpu::TextureFormat::ASTC5x5UnormSrgb:
-        case wgpu::TextureFormat::ASTC6x5Unorm:
-        case wgpu::TextureFormat::ASTC6x5UnormSrgb:
-        case wgpu::TextureFormat::ASTC6x6Unorm:
-        case wgpu::TextureFormat::ASTC6x6UnormSrgb:
-        case wgpu::TextureFormat::ASTC8x5Unorm:
-        case wgpu::TextureFormat::ASTC8x5UnormSrgb:
-        case wgpu::TextureFormat::ASTC8x6Unorm:
-        case wgpu::TextureFormat::ASTC8x6UnormSrgb:
-        case wgpu::TextureFormat::ASTC8x8Unorm:
-        case wgpu::TextureFormat::ASTC8x8UnormSrgb:
-        case wgpu::TextureFormat::ASTC10x5Unorm:
-        case wgpu::TextureFormat::ASTC10x5UnormSrgb:
-        case wgpu::TextureFormat::ASTC10x6Unorm:
-        case wgpu::TextureFormat::ASTC10x6UnormSrgb:
-        case wgpu::TextureFormat::ASTC10x8Unorm:
-        case wgpu::TextureFormat::ASTC10x8UnormSrgb:
-        case wgpu::TextureFormat::ASTC10x10Unorm:
-        case wgpu::TextureFormat::ASTC10x10UnormSrgb:
-        case wgpu::TextureFormat::ASTC12x10Unorm:
-        case wgpu::TextureFormat::ASTC12x10UnormSrgb:
-        case wgpu::TextureFormat::ASTC12x12Unorm:
-        case wgpu::TextureFormat::ASTC12x12UnormSrgb:
-        case wgpu::TextureFormat::R16Unorm:
-        case wgpu::TextureFormat::RG16Unorm:
-        case wgpu::TextureFormat::RGBA16Unorm:
-        case wgpu::TextureFormat::R16Snorm:
-        case wgpu::TextureFormat::RG16Snorm:
-        case wgpu::TextureFormat::RGBA16Snorm:
-        case wgpu::TextureFormat::R8BG8Biplanar420Unorm:
-        case wgpu::TextureFormat::R10X6BG10X6Biplanar420Unorm:
-        case wgpu::TextureFormat::R8BG8A8Triplanar420Unorm:
-        case wgpu::TextureFormat::R8BG8Biplanar422Unorm:
-        case wgpu::TextureFormat::R8BG8Biplanar444Unorm:
-        case wgpu::TextureFormat::R10X6BG10X6Biplanar422Unorm:
-        case wgpu::TextureFormat::R10X6BG10X6Biplanar444Unorm:
-            return ScalarSampleType::F32;
-        case wgpu::TextureFormat::Depth16Unorm:
-        case wgpu::TextureFormat::Depth24Plus:
-        case wgpu::TextureFormat::Depth24PlusStencil8:
-        case wgpu::TextureFormat::Depth32Float:
-        case wgpu::TextureFormat::Depth32FloatStencil8:
-            PANIC_POSTCONDITION("A depth texture format requires special sampler treatment and "
-                                "does not generally support linear filtering (needed for mipmap "
-                                "generation). Thus no applicable scalar sample type for %d",
-                    format);
-            break;
-        case wgpu::TextureFormat::Undefined:
-        case wgpu::TextureFormat::External:
-            PANIC_POSTCONDITION("No scalar sample type for texture format %d", format);
-            break;
-    }
-}
-
-void WebGPURenderPassMipmapGenerator::generateMipmaps(wgpu::Queue const& queue,
-        wgpu::Texture const& texture) {
-    const uint32_t mipLevelCount{ texture.GetMipLevelCount() };
-    if (mipLevelCount < 2) {
-        return; // nothing to do
-    }
-    wgpu::RenderPipeline const& pipeline{ getOrCreatePipelineFor(texture.GetFormat()) };
-    const wgpu::CommandEncoderDescriptor commandEncoderDescriptor{
-        .label = "mipmap_generation_render_pass_cmd_encoder",
-    };
-    const wgpu::CommandEncoder commandEncoder{ mDevice.CreateCommandEncoder(
-            &commandEncoderDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(commandEncoder)
-            << "Failed to create command encoder for layer  for render pass mipmap generation?";
-    const uint32_t layerCount{ texture.GetDepthOrArrayLayers() };
-    for (uint32_t layer = 0; layer < layerCount; layer++) {
-        for (uint32_t mipLevel = 1; mipLevel < mipLevelCount; mipLevel++) {
-            generateMipmap(commandEncoder, texture, pipeline, layer, mipLevel);
-        }
-    }
-    // submit the command buffer...
-    const wgpu::CommandBufferDescriptor commandBufferDescriptor{
-        .label = "mipmap_generation_render_pass_cmd_buffer",
-    };
-    const wgpu::CommandBuffer commandBuffer{ commandEncoder.Finish(&commandBufferDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(commandBuffer)
-            << "Failed to create command buffer for layer  for render pass mipmap generation?";
-    queue.Submit(1, &commandBuffer);
-}
-
-void WebGPURenderPassMipmapGenerator::generateMipmap(wgpu::CommandEncoder const& commandEncoder,
-        const wgpu::Texture& texture, const wgpu::RenderPipeline& pipeline, const uint32_t layer,
-        const uint32_t mipLevel) {
-    // create texture views for this pass...
-    const wgpu::TextureFormat format{ texture.GetFormat() };
-    // only 2D textures supported at this time...
-    const wgpu::TextureViewDimension dimension{ wgpu::TextureViewDimension::e2D };
-    const wgpu::TextureViewDescriptor sourceViewDescriptor{
-        .label = "previous_mip_level_texture_view",
-        .format = format,
-        .dimension = dimension,
-        .baseMipLevel = mipLevel - 1,
-        .mipLevelCount = 1,
-        .baseArrayLayer = layer,
-        .arrayLayerCount = 1,
-        .aspect = wgpu::TextureAspect::All,
-        .usage = wgpu::TextureUsage::TextureBinding,
-    };
-    const wgpu::TextureView sourceView{ texture.CreateView(&sourceViewDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(pipeline)
-            << "Failed to create source texture view for layer " << layer << " and mip level "
-            << mipLevel << " for render pass mipmap generation?";
-    const wgpu::TextureViewDescriptor destinationViewDescriptor{
-        .label = "next_mip_level_texture_view",
-        .format = format,
-        .dimension = dimension,
-        .baseMipLevel = mipLevel,
-        .mipLevelCount = 1,
-        .baseArrayLayer = layer,
-        .arrayLayerCount = 1,
-        .aspect = wgpu::TextureAspect::All,
-        .usage = wgpu::TextureUsage::RenderAttachment,
-    };
-    const wgpu::TextureView destinationView{ texture.CreateView(&destinationViewDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(pipeline)
-            << "Failed to create destination texture view for layer " << layer << " and mip level "
-            << mipLevel << " for render pass mipmap generation?";
-    // create the render pass...
-    const wgpu::BindGroupEntry textureBindGroupEntries[TEXTURE_BIND_GROUP_ENTRY_SIZE]{
-        {
-            .binding = SAMPLER_BINDING_INDEX,
-            .sampler = mPreviousMipLevelSampler,
-        },
-        {
-            .binding = TEXTURE_BINDING_INDEX,
-            .textureView = sourceView,
-        },
-    };
-    const wgpu::BindGroupDescriptor textureBindGroupDescriptor{
-        .label = "render_pass_mipmap_generation_texture_bind_group",
-        .layout = mTextureBindGroupLayout,
-        .entryCount = TEXTURE_BIND_GROUP_ENTRY_SIZE,
-        .entries = textureBindGroupEntries,
-    };
-    const wgpu::BindGroup textureBindGroup{ mDevice.CreateBindGroup(&textureBindGroupDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(pipeline)
-            << "Failed to create texture bind group for layer " << layer << " and mip level "
-            << mipLevel << " for render pass mipmap generation?";
-    const wgpu::RenderPassColorAttachment colorAttachment{
-        .view = destinationView,
-        .depthSlice = wgpu::kDepthSliceUndefined, // not applicable
-        .resolveTarget = nullptr,                 // not applicable
-        .loadOp = wgpu::LoadOp::Clear,
-        .storeOp = wgpu::StoreOp::Store,
-        .clearValue = { .r = 0.0, .g = 0.0, .b = 0.0, .a = 1.0 },
-    };
-    const wgpu::RenderPassDescriptor renderPassDescriptor{
-        .label = "mipmap_generation_render_pass",
-        .colorAttachmentCount = 1,
-        .colorAttachments = &colorAttachment,
-        .depthStencilAttachment = nullptr, // not applicable
-        .occlusionQuerySet = nullptr,      // not applicable
-        .timestampWrites = nullptr,        // not applicable
-    };
-    const wgpu::RenderPassEncoder renderPassEncoder{ commandEncoder.BeginRenderPass(
-            &renderPassDescriptor) };
-    FILAMENT_CHECK_POSTCONDITION(renderPassEncoder)
-            << "Failed to create render pass encoder for layer " << layer << " and mip level "
-            << mipLevel << " for render pass mipmap generation?";
-    renderPassEncoder.SetPipeline(pipeline);
-    renderPassEncoder.SetBindGroup(TEXTURE_BIND_GROUP_INDEX, textureBindGroup);
-    renderPassEncoder.Draw(3); // draw the full-screen triangle
-                                          // with hard-coded vertices in the shader
-    renderPassEncoder.End();
-}
-
-wgpu::RenderPipeline& WebGPURenderPassMipmapGenerator::getOrCreatePipelineFor(
-        const wgpu::TextureFormat textureFormat) {
-    const uint32_t key{ static_cast<uint32_t>(textureFormat) };
-    if (mPipelineByTextureFormat.find(key) == mPipelineByTextureFormat.end()) {
-        mPipelineByTextureFormat[key] =
-                createPipeline(mDevice, mShaderModule, mPipelineLayout, textureFormat);
-    }
-    return mPipelineByTextureFormat[key];
-}
-
-} // namespace filament::backend
@@ -1,69 +0,0 @@
-/*
- * 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 TNT_FILAMENT_BACKEND_WEBGPURENDERPASSMIPMAPGENERATOR_H
-#define TNT_FILAMENT_BACKEND_WEBGPURENDERPASSMIPMAPGENERATOR_H
-
-#include <utils/Panic.h>
-
-#include <tsl/robin_map.h>
-#include <webgpu/webgpu_cpp.h>
-
-#include <cstdint>
-#include <string_view>
-
-namespace filament::backend {
-
-class WebGPURenderPassMipmapGenerator final {
-public:
-    struct FormatCompatibility final {
-        bool compatible{ false };
-        std::string_view reason;
-    };
-
-    [[nodiscard]] static FormatCompatibility getCompatibilityFor(wgpu::TextureFormat,
-            wgpu::TextureDimension, uint32_t sampleCount);
-
-    explicit WebGPURenderPassMipmapGenerator(wgpu::Device const&);
-
-    void generateMipmaps(wgpu::Queue const&, wgpu::Texture const&);
-
-private:
-    enum class ScalarSampleType : uint8_t {
-        F32,
-        I32,
-        U32,
-    };
-
-    [[nodiscard]] constexpr static ScalarSampleType getScalarSampleTypeFrom(
-            wgpu::TextureFormat format);
-
-    [[nodiscard]] wgpu::RenderPipeline& getOrCreatePipelineFor(wgpu::TextureFormat);
-
-    void generateMipmap(wgpu::CommandEncoder const&, wgpu::Texture const&,
-            wgpu::RenderPipeline const&, uint32_t layer, uint32_t mipLevel);
-
-    wgpu::Device const& mDevice;
-    const wgpu::Sampler mPreviousMipLevelSampler{ nullptr };
-    const wgpu::ShaderModule mShaderModule{ nullptr };
-    const wgpu::BindGroupLayout mTextureBindGroupLayout{ nullptr };
-    const wgpu::PipelineLayout mPipelineLayout{ nullptr };
-    tsl::robin_map<uint32_t, wgpu::RenderPipeline> mPipelineByTextureFormat;
-};
-
-} // namespace filament::backend
-
-#endif // TNT_FILAMENT_BACKEND_WEBGPURENDERPASSMIPMAPGENERATOR_H
@@ -16,11 +16,7 @@

 #include "WebGPURenderTarget.h"

-#include "WebGPUTexture.h"
-
-#include "DriverBase.h"
 #include <backend/DriverEnums.h>
-#include <backend/Handle.h>
 #include <backend/TargetBufferInfo.h>

 #include <private/backend/BackendUtils.h>
@@ -30,120 +26,30 @@

 #include <webgpu/webgpu_cpp.h>

-#include <algorithm>
-#include <array>
 #include <cstdint>
-#include <functional>
-#include <string_view>

 namespace filament::backend {

-namespace {
-
-/**
- * Panics if the number of samples in the original attachment textures do not match.
- * @return The number of samples in the original attachment textures (the number/count in each one).
- *         Returns 0 if there are no attachments.
- */
-[[nodiscard]] uint8_t createMsaaSidecarTextures(const uint8_t renderTargetSampleCount,
-        const TargetBufferFlags targetFlags, MRT const& colorAttachments,
-        TargetBufferInfo const& depthAttachment, TargetBufferInfo const& stencilAttachment,
-        std::function<WebGPUTexture*(const Handle<HwTexture>)> const& getWebGPUTexture,
-        wgpu::Device const& device) {
-    struct Target final {
-        std::string_view name;
-        TargetBufferFlags flag{ TargetBufferFlags::NONE };
-        size_t colorIndex{ 0 };
-    };
-    // assuming 8 colors. hopefully the following static_assert will get tripped if another
-    // color ever gets added
-    static_assert(
-            (TargetBufferFlags::COLOR0 | TargetBufferFlags::COLOR1 | TargetBufferFlags::COLOR2 |
-                    TargetBufferFlags::COLOR3 | TargetBufferFlags::COLOR4 |
-                    TargetBufferFlags::COLOR5 | TargetBufferFlags::COLOR6 |
-                    TargetBufferFlags::COLOR7) == TargetBufferFlags::COLOR_ALL);
-    const static std::array TARGETS{
-        Target{ .name = "COLOR0", .flag = TargetBufferFlags::COLOR0, .colorIndex = 0 },
-        Target{ .name = "COLOR1", .flag = TargetBufferFlags::COLOR1, .colorIndex = 1 },
-        Target{ .name = "COLOR2", .flag = TargetBufferFlags::COLOR2, .colorIndex = 2 },
-        Target{ .name = "COLOR3", .flag = TargetBufferFlags::COLOR3, .colorIndex = 3 },
-        Target{ .name = "COLOR4", .flag = TargetBufferFlags::COLOR4, .colorIndex = 4 },
-        Target{ .name = "COLOR5", .flag = TargetBufferFlags::COLOR5, .colorIndex = 5 },
-        Target{ .name = "COLOR6", .flag = TargetBufferFlags::COLOR6, .colorIndex = 6 },
-        Target{ .name = "COLOR7", .flag = TargetBufferFlags::COLOR7, .colorIndex = 7 },
-        Target{ .name = "DEPTH", .flag = TargetBufferFlags::DEPTH },
-        Target{ .name = "STENCIL", .flag = TargetBufferFlags::STENCIL },
-    };
-#ifndef NDEBUG
-    for (auto const& target: TARGETS) {
-        assert_invariant(target.colorIndex <= MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT &&
-                         "color index is >= MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT, which should "
-                         "not be possible and could lead to us indexing into the colorAttachments "
-                         "array beyond its bounds.");
-    }
-#endif
-    bool firstAttachment{ true };
-    uint8_t sampleCountPerAttachment{ 0 };
-    for (auto const& target: TARGETS) {
-        if (any(targetFlags & target.flag)) {
-            const Handle<HwTexture> textureHandle{
-                target.flag == TargetBufferFlags::DEPTH
-                        ? depthAttachment.handle
-                        : (target.flag == TargetBufferFlags::STENCIL
-                                          ? stencilAttachment.handle
-                                          : colorAttachments[target.colorIndex].handle)
-            };
-            WebGPUTexture* const texture{ getWebGPUTexture(textureHandle) };
-            assert_invariant(texture != nullptr && "target flag indicate the use of an attachment "
-                                                   "for which we do not have a texture?");
-            if (firstAttachment) {
-                sampleCountPerAttachment = texture->samples;
-                firstAttachment = false;
-            }
-            FILAMENT_CHECK_PRECONDITION(texture->samples == sampleCountPerAttachment)
-                    << target.name << " attachment texture has " << +texture->samples
-                    << " but the other attachment(s) have " << +sampleCountPerAttachment;
-            if (renderTargetSampleCount > 1 && sampleCountPerAttachment == 1) {
-                texture->createMsaaSidecarTextureIfNotAlreadyCreated(renderTargetSampleCount,
-                        device);
-            }
-        }
-    }
-    assert_invariant(sampleCountPerAttachment);
-    return sampleCountPerAttachment;
-}
-
-}  // namespace
-
 WebGPURenderTarget::WebGPURenderTarget(const uint32_t width, const uint32_t height,
        const uint8_t samples, const uint8_t layerCount, MRT const& colorAttachmentsMRT,
-        Attachment const& depthAttachmentInfo, Attachment const& stencilAttachmentInfo,
-        TargetBufferFlags const& targetFlags,
-        std::function<WebGPUTexture*(const Handle<HwTexture>)> const& getWebGPUTexture,
-        wgpu::Device const& device)
+        Attachment const& depthAttachmentInfo, Attachment const& stencilAttachmentInfo)
    : HwRenderTarget{ width, height },
      mDefaultRenderTarget{ false },
-      mTargetFlags{ targetFlags },
      mSamples{ samples },
      mLayerCount{ layerCount },
      mColorAttachments{ colorAttachmentsMRT },
      mDepthAttachment{ depthAttachmentInfo },
-      mStencilAttachment{ stencilAttachmentInfo },
-      mSampleCountPerAttachment{ createMsaaSidecarTextures(mSamples, mTargetFlags,
-              mColorAttachments, mDepthAttachment, mStencilAttachment, getWebGPUTexture, device) } {
-    // TODO consider possibly making this an array (that would avoid a heap allocation, but the
-    //      concern is the size limitation on the handle itself)
-    mColorAttachmentDesc.reserve(MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT);
+      mStencilAttachment{ stencilAttachmentInfo } {
+    // TODO consider making this an array
+    mColorAttachmentDescriptors.reserve(MRT::MAX_SUPPORTED_RENDER_TARGET_COUNT);
 }

 // Default constructor for the default render target
 WebGPURenderTarget::WebGPURenderTarget()
    : HwRenderTarget{ 0, 0 },
      mDefaultRenderTarget{ true },
-      mTargetFlags{ TargetBufferFlags::NONE },
      mSamples{ 1 },
-      mLayerCount{ 1 },
-      mSampleCountPerAttachment{ 1 } {}
+      mLayerCount{ 1 } {}

 wgpu::LoadOp WebGPURenderTarget::getLoadOperation(RenderPassParams const& params,
        const TargetBufferFlags bufferToOperateOn) {
@@ -151,7 +57,7 @@ wgpu::LoadOp WebGPURenderTarget::getLoadOperation(RenderPassParams const& params
        return wgpu::LoadOp::Clear;
    }
    if (any(params.flags.discardStart & bufferToOperateOn)) {
-        return wgpu::LoadOp::Clear;
+        return wgpu::LoadOp::Clear; // Or wgpu::LoadOp::Undefined if clear is not desired on discard
    }
    return wgpu::LoadOp::Load;
 }
@@ -167,137 +73,128 @@ wgpu::StoreOp WebGPURenderTarget::getStoreOperation(RenderPassParams const& para
 void WebGPURenderTarget::setUpRenderPassAttachments(wgpu::RenderPassDescriptor& outDescriptor,
        RenderPassParams const& params, wgpu::TextureView const& defaultColorTextureView,
        wgpu::TextureView const& defaultDepthStencilTextureView,
-        wgpu::TextureView const* customColorTextureViews,
-        wgpu::TextureView const* customColorMsaaSidecarTextureViews,
-        uint32_t customColorTextureViewCount,
-        wgpu::TextureView const& customDepthStencilTextureView,
-        wgpu::TextureView const& customDepthStencilMsaaSidecarTextureView) {
-    const bool hasMsaaSidecars{ (customColorTextureViewCount > 0 &&
-                                        customColorMsaaSidecarTextureViews[0]) ||
-                                customDepthStencilMsaaSidecarTextureView };
-    // either all the textures have MSAA sidecars or none of them do
-    if (hasMsaaSidecars) {
-        FILAMENT_CHECK_PRECONDITION(std::all_of(customColorMsaaSidecarTextureViews,
-                customColorMsaaSidecarTextureViews + customColorTextureViewCount,
-                [](wgpu::TextureView const& msaaView) { return msaaView != nullptr; }))
-                << "A color or depth/stencil attachment texture has a MSAA sidecar but at least "
-                   "one other color attachment texture does not.";
-        FILAMENT_CHECK_PRECONDITION(customDepthStencilMsaaSidecarTextureView != nullptr)
-                << "The color attachment texture(s) have MSAA sidecar(s) but the depth/stencil "
-                   "texture does not.";
-    } else {
-        FILAMENT_CHECK_PRECONDITION(std::all_of(customColorMsaaSidecarTextureViews,
-                customColorMsaaSidecarTextureViews + customColorTextureViewCount,
-                [](wgpu::TextureView const& msaaView) { return msaaView == nullptr; }))
-                << "A color or depth/stencil attachment texture does not have a MSAA sidecar but "
-                   "at least one color attachment texture does.";
-        FILAMENT_CHECK_PRECONDITION(customDepthStencilMsaaSidecarTextureView == nullptr)
-                << "Custom color textures for the render target do not have MSAA sidecar(s) but "
-                   "the depth/stencil texture does.";
-    }
+        wgpu::TextureFormat const& defaultDepthStencilFormat,
+        wgpu::TextureView const* customColorTextureViews, uint32_t customColorTextureViewCount,
+        wgpu::TextureView const& customDepthTextureView,
+        wgpu::TextureView const& customStencilTextureView,
+        const wgpu::TextureFormat customDepthFormat,
+        const wgpu::TextureFormat customStencilFormat) {
+    mColorAttachmentDescriptors.clear();
+    mHasDepthStencilAttachment = false;

-    mColorAttachmentDesc.clear();
-
-    const bool hasDepth = any(mTargetFlags & TargetBufferFlags::DEPTH);
-    const bool hasStencil = any(mTargetFlags & TargetBufferFlags::STENCIL);
-    mHasDepthStencilAttachment = hasDepth || hasStencil;
-    bool const depthReadOnly = (params.readOnlyDepthStencil & RenderPassParams::READONLY_DEPTH) > 0;
-
-    // Color attachments
    if (mDefaultRenderTarget) {
        assert_invariant(defaultColorTextureView);
-        mColorAttachmentDesc.push_back({
-            .view = defaultColorTextureView,
+        mColorAttachmentDescriptors.push_back({ .view = defaultColorTextureView,
            .resolveTarget = nullptr,
            .loadOp = WebGPURenderTarget::getLoadOperation(params, TargetBufferFlags::COLOR0),
            .storeOp = WebGPURenderTarget::getStoreOperation(params, TargetBufferFlags::COLOR0),
-            .clearValue = {
-                .r = params.clearColor.r,
-                .g = params.clearColor.g,
-                .b = params.clearColor.b,
-                .a = params.clearColor.a,
-            },
-        });
-    } else {
+            .clearValue = { params.clearColor.r, params.clearColor.g, params.clearColor.b,
+                params.clearColor.a } });
+
+        if (defaultDepthStencilTextureView) {
+            mDepthStencilAttachmentDescriptor = {
+                .view = defaultDepthStencilTextureView,
+                .depthLoadOp =
+                        WebGPURenderTarget::getLoadOperation(params, TargetBufferFlags::DEPTH),
+                .depthStoreOp =
+                        WebGPURenderTarget::getStoreOperation(params, TargetBufferFlags::DEPTH),
+                .depthClearValue = static_cast<float>(params.clearDepth),
+                .depthReadOnly =
+                        (params.readOnlyDepthStencil & RenderPassParams::READONLY_DEPTH) > 0,
+                .stencilLoadOp = wgpu::LoadOp::Undefined,
+                .stencilStoreOp = wgpu::StoreOp::Undefined,
+                .stencilClearValue = params.clearStencil,
+                .stencilReadOnly =
+                        (params.readOnlyDepthStencil & RenderPassParams::READONLY_STENCIL) > 0,
+            };
+
+            if (defaultDepthStencilFormat == wgpu::TextureFormat::Depth24PlusStencil8 ||
+                    defaultDepthStencilFormat == wgpu::TextureFormat::Depth32FloatStencil8 ||
+                    defaultDepthStencilFormat == wgpu::TextureFormat::Stencil8) {
+                mDepthStencilAttachmentDescriptor.stencilLoadOp =
+                        WebGPURenderTarget::getLoadOperation(params, TargetBufferFlags::STENCIL);
+                mDepthStencilAttachmentDescriptor.stencilStoreOp =
+                        WebGPURenderTarget::getStoreOperation(params, TargetBufferFlags::STENCIL);
+            }
+            mHasDepthStencilAttachment = true;
+        }
+    } else { // Custom Render Target
        for (uint32_t i = 0; i < customColorTextureViewCount; ++i) {
            if (customColorTextureViews[i]) {
-                const wgpu::TextureView msaaSidecar{ customColorMsaaSidecarTextureViews[i] };
-                mColorAttachmentDesc.push_back({
-                    .view = hasMsaaSidecars ? msaaSidecar : customColorTextureViews[i],
-                    .resolveTarget = hasMsaaSidecars ? customColorTextureViews[i] : nullptr,
+                mColorAttachmentDescriptors.push_back({ .view = customColorTextureViews[i],
+                    // .resolveTarget = nullptr; // TODO: MSAA resolve for custom RT
                    .loadOp =
                            WebGPURenderTarget::getLoadOperation(params, getTargetBufferFlagsAt(i)),
                    .storeOp = WebGPURenderTarget::getStoreOperation(params,
                            getTargetBufferFlagsAt(i)),
-                    .clearValue = {
-                        .r = params.clearColor.r,
+                    .clearValue = { .r = params.clearColor.r,
                        .g = params.clearColor.g,
                        .b = params.clearColor.b,
-                        .a = params.clearColor.a,
-                    },
-                });
-            }
-        }
-    }
-    outDescriptor.colorAttachmentCount = mColorAttachmentDesc.size();
-    outDescriptor.colorAttachments = mColorAttachmentDesc.data();
-
-    // Depth/Stencil Attachments
-    if (mHasDepthStencilAttachment) {
-        wgpu::TextureView depthStencilViewToUse{ nullptr };
-        if (mDefaultRenderTarget) {
-            depthStencilViewToUse = defaultDepthStencilTextureView;
-            assert_invariant(depthStencilViewToUse);
-        } else {
-            if (customDepthStencilTextureView) {
-                depthStencilViewToUse = hasMsaaSidecars ? customDepthStencilMsaaSidecarTextureView
-                                                        : customDepthStencilTextureView;
+                        .a = params.clearColor.a } });
            }
        }

-        if (depthStencilViewToUse) {
-            mDepthStencilAttachmentDesc = {};
-            mDepthStencilAttachmentDesc.view = depthStencilViewToUse;
+        FILAMENT_CHECK_POSTCONDITION(!(customDepthTextureView && customStencilTextureView))
+                << "WebGPU CANNOT support separate texture views for depth + stencil. depth + "
+                   "stencil needs to be in one texture view";
+
+        const bool hasStencil =
+                customStencilTextureView ||
+                (customDepthFormat == wgpu::TextureFormat::Depth24PlusStencil8 ||
+                        customDepthFormat == wgpu::TextureFormat::Depth32FloatStencil8);
+
+        const bool hasDepth =
+                customDepthTextureView ||
+                (customStencilFormat == wgpu::TextureFormat::Depth24PlusStencil8 ||
+                        customDepthFormat == wgpu::TextureFormat::Depth32FloatStencil8);
+
+        if (customDepthTextureView || customStencilTextureView) {
+            assert_invariant((hasDepth || hasStencil) &&
+                             "Depth or Texture view without a valid texture format");
+            mDepthStencilAttachmentDescriptor = {};
+            mDepthStencilAttachmentDescriptor.view =
+                    customDepthTextureView ? customDepthTextureView : customStencilTextureView;

            if (hasDepth) {
-                mDepthStencilAttachmentDesc.depthLoadOp =
-                        depthReadOnly ? wgpu::LoadOp::Undefined
-                                      : getLoadOperation(params, TargetBufferFlags::DEPTH);
-                mDepthStencilAttachmentDesc.depthStoreOp =
-                        depthReadOnly ? wgpu::StoreOp::Undefined
-                                      : getStoreOperation(params, TargetBufferFlags::DEPTH);
-                mDepthStencilAttachmentDesc.depthClearValue = static_cast<float>(params.clearDepth);
-                mDepthStencilAttachmentDesc.depthReadOnly = depthReadOnly;
+                mDepthStencilAttachmentDescriptor.depthLoadOp =
+                        WebGPURenderTarget::getLoadOperation(params, TargetBufferFlags::DEPTH);
+                mDepthStencilAttachmentDescriptor.depthStoreOp =
+                        WebGPURenderTarget::getStoreOperation(params, TargetBufferFlags::DEPTH);
+                mDepthStencilAttachmentDescriptor.depthClearValue =
+                        static_cast<float>(params.clearDepth);
+                mDepthStencilAttachmentDescriptor.depthReadOnly =
+                        (params.readOnlyDepthStencil & RenderPassParams::READONLY_DEPTH) > 0;
            } else {
-                mDepthStencilAttachmentDesc.depthLoadOp = wgpu::LoadOp::Undefined;
-                mDepthStencilAttachmentDesc.depthStoreOp = wgpu::StoreOp::Undefined;
-                mDepthStencilAttachmentDesc.depthReadOnly = true;
+                mDepthStencilAttachmentDescriptor.depthLoadOp = wgpu::LoadOp::Undefined;
+                mDepthStencilAttachmentDescriptor.depthStoreOp = wgpu::StoreOp::Undefined;
+                mDepthStencilAttachmentDescriptor.depthReadOnly = true;
            }

            if (hasStencil) {
-                mDepthStencilAttachmentDesc.stencilLoadOp =
-                        getLoadOperation(params, TargetBufferFlags::STENCIL);
-                mDepthStencilAttachmentDesc.stencilStoreOp =
-                        getStoreOperation(params, TargetBufferFlags::STENCIL);
-                mDepthStencilAttachmentDesc.stencilClearValue = params.clearStencil;
-                mDepthStencilAttachmentDesc.stencilReadOnly =
+                mDepthStencilAttachmentDescriptor.stencilLoadOp =
+                        WebGPURenderTarget::getLoadOperation(params, TargetBufferFlags::STENCIL);
+                mDepthStencilAttachmentDescriptor.stencilStoreOp =
+                        WebGPURenderTarget::getStoreOperation(params, TargetBufferFlags::STENCIL);
+                mDepthStencilAttachmentDescriptor.stencilClearValue = params.clearStencil;
+                mDepthStencilAttachmentDescriptor.stencilReadOnly =
                        (params.readOnlyDepthStencil & RenderPassParams::READONLY_STENCIL) > 0;
            } else {
-                mDepthStencilAttachmentDesc.stencilLoadOp = wgpu::LoadOp::Undefined;
-                mDepthStencilAttachmentDesc.stencilStoreOp = wgpu::StoreOp::Undefined;
-                mDepthStencilAttachmentDesc.stencilReadOnly = true;
+                mDepthStencilAttachmentDescriptor.stencilLoadOp = wgpu::LoadOp::Undefined;
+                mDepthStencilAttachmentDescriptor.stencilStoreOp = wgpu::StoreOp::Undefined;
+                mDepthStencilAttachmentDescriptor.stencilReadOnly = true;
            }
-            outDescriptor.depthStencilAttachment = &mDepthStencilAttachmentDesc;
-
-        } else {
-            outDescriptor.depthStencilAttachment = nullptr;
-            mDepthStencilAttachmentDesc = {};
+            mHasDepthStencilAttachment = true;
        }
-
-    } else {
-        outDescriptor.depthStencilAttachment = nullptr;
-        mDepthStencilAttachmentDesc = {};
    }
+
+    outDescriptor.colorAttachmentCount = mColorAttachmentDescriptors.size();
+    outDescriptor.colorAttachments = mColorAttachmentDescriptors.data();
+    outDescriptor.depthStencilAttachment =
+            mHasDepthStencilAttachment ? &mDepthStencilAttachmentDescriptor : nullptr;
+
+    // descriptor.sampleCount was removed from the core spec. If your webgpu.h still has it,
+    // and your Dawn version expects it, you might need to set it here based on this->samples.
+    // e.g., descriptor.sampleCount = this->samples;
 }

-} // namespace filament::backend
+}// namespace filament::backend
@@ -17,8 +17,6 @@
 #ifndef TNT_FILAMENT_BACKEND_WEBGPUHANDLES_H
 #define TNT_FILAMENT_BACKEND_WEBGPUHANDLES_H

-#include "WebGPUTexture.h"
-
 #include "DriverBase.h"
 #include <backend/DriverEnums.h>
 #include <backend/TargetBufferInfo.h>
@@ -26,7 +24,6 @@
 #include <webgpu/webgpu_cpp.h>

 #include <cstdint>
-#include <functional>
 #include <vector>

 namespace filament::backend {
@@ -37,44 +34,44 @@ public:

    WebGPURenderTarget(uint32_t width, uint32_t height, uint8_t samples, uint8_t layerCount,
            MRT const& colorAttachments, Attachment const& depthAttachment,
-            Attachment const& stencilAttachment, TargetBufferFlags const& targetFlags,
-            std::function<WebGPUTexture*(const Handle<HwTexture>)> const&, wgpu::Device const&);
+            Attachment const& stencilAttachment);

    // Default constructor for the default render target
    WebGPURenderTarget();

-    void setUpRenderPassAttachments(wgpu::RenderPassDescriptor& outDescriptor,
+    // Updated signature: takes resolved views for custom RTs, and default views for default RT
+    void setUpRenderPassAttachments(
+            wgpu::RenderPassDescriptor& outDescriptor,
            RenderPassParams const& params,
            // For default render target:
            wgpu::TextureView const& defaultColorTextureView,
            wgpu::TextureView const& defaultDepthStencilTextureView,
+            wgpu::TextureFormat const& defaultDepthStencilFormat,
            // For custom render targets:
-            wgpu::TextureView const* customColorTextureViews,            // Array of views
-            wgpu::TextureView const* customColorMsaaSidecarTextureViews, // nullptrs if N/A
+            wgpu::TextureView const* customColorTextureViews, // Array of views
            uint32_t customColorTextureViewCount,
-            wgpu::TextureView const& customDepthStencilTextureView,
-            wgpu::TextureView const& customDepthStencilMsaaSidecarTextureView /* nullptr if N/A */);
+            wgpu::TextureView const& customDepthTextureView,
+            wgpu::TextureView const& customStencilTextureView,
+            wgpu::TextureFormat customDepthFormat,
+            wgpu::TextureFormat customStencilFormat);

    [[nodiscard]] bool isDefaultRenderTarget() const { return mDefaultRenderTarget; }
    [[nodiscard]] uint8_t getSamples() const { return mSamples; }
-    [[nodiscard]] uint8_t getSampleCountPerAttachment() const { return mSampleCountPerAttachment; }
    [[nodiscard]] uint8_t getLayerCount() const { return mLayerCount; }

+    // Accessors for the driver to get stored attachment info
    [[nodiscard]] MRT const& getColorAttachmentInfos() const { return mColorAttachments; }
    [[nodiscard]] Attachment const& getDepthAttachmentInfo() const { return mDepthAttachment; }
    [[nodiscard]] Attachment const& getStencilAttachmentInfo() const { return mStencilAttachment; }

+    // Static helpers for load/store operations
    [[nodiscard]] static wgpu::LoadOp getLoadOperation(RenderPassParams const& params,
            TargetBufferFlags buffer);
    [[nodiscard]] static wgpu::StoreOp getStoreOperation(RenderPassParams const& params,
            TargetBufferFlags buffer);

-    [[nodiscard]] TargetBufferFlags getTargetFlags() const { return mTargetFlags; }
-    void setTargetFlags( TargetBufferFlags value) { mTargetFlags = value; }
-
 private:
    bool mDefaultRenderTarget = false;
-    TargetBufferFlags mTargetFlags = TargetBufferFlags::NONE;
    uint8_t mSamples = 1;
    uint8_t mLayerCount = 1;

@@ -84,11 +81,9 @@ private:
    Attachment mDepthAttachment{};
    Attachment mStencilAttachment{};

-    uint8_t mSampleCountPerAttachment = 0;
-
    // Cached descriptors for the render pass
-    std::vector<wgpu::RenderPassColorAttachment> mColorAttachmentDesc;
-    wgpu::RenderPassDepthStencilAttachment mDepthStencilAttachmentDesc{};
+    std::vector<wgpu::RenderPassColorAttachment> mColorAttachmentDescriptors;
+    wgpu::RenderPassDepthStencilAttachment mDepthStencilAttachmentDescriptor{};
    bool mHasDepthStencilAttachment = false;
 };

@@ -21,27 +21,50 @@

 #include <backend/DriverEnums.h>

+#include <utils/Panic.h>
+#include <utils/ostream.h>
+
+#if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
 #include <dawn/webgpu_cpp_print.h>
+#endif
 #include <webgpu/webgpu_cpp.h>

 #include <cstdint>
+#if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
 #include <sstream>
-#include <string>
+#endif
 #include <string_view>

 /**
 * Reusable set of convenience functions for strings -- generally string views, literals, &
- * strings -- used in the WebGPU backend
+ * streaming -- used in the WebGPU backend
 */

 namespace filament::backend {

 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
+/**
+ * Convenience template to print WGPU types (which don't support Filament's utils::io::ostream)
+ * @tparam WebGPUPrintable e.g. wgpu::FeatureName type
+ * @param out stream to print to
+ * @param printable the instance to print
+ * @return the stream printed to
+ *
+ * Example usage (because including the template operator override itself does not compile):
+ * #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
+ * utils::io::ostream& operator<<(utils::io::ostream& out,
+ *       const wgpu::FeatureName featureName) noexcept {
+ *   return streamInsertWebGPUPrintable(out, featureName);
+ * }
+ * #endif
+ */
 template<typename WebGPUPrintable>
-[[nodiscard]] inline std::string webGPUPrintableToString(const WebGPUPrintable printable) {
-    std::stringstream out;
-    out << printable;
-    return out.str();
+utils::io::ostream& streamInsertWebGPUPrintable(utils::io::ostream& out,
+        const WebGPUPrintable printable) {
+    std::stringstream printableStream;
+    printableStream << printable;
+    out << printableStream.str();
+    return out;
 }
 #endif

@@ -92,17 +115,46 @@ template<typename WebGPUPrintable>
    }
 }

-[[nodiscard]] inline std::string adapterOptionsToString(
-        wgpu::RequestAdapterOptions const& options) {
-    std::stringstream out;
+/**
+ * Convenience template to print wgpu::RequestAdapterOptions
+ * @tparam STREAM_TYPE useful namely for streaming to either an utils::io::ostream OR
+ * utils::details::PanicStream, but also for any kind of stream
+ * @param out stream to print to
+ * @param options instance to be printed
+ * @return stream printed to
+ *
+ * Example usage (because including the template operator override itself does not compile):
+ * template<typename STREAM_TYPE>
+ * STREAM_TYPE& operator<<(STREAM_TYPE& out, wgpu::RequestAdapterOptions const& options) noexcept {
+ *   return streamInsertRequestAdapterOptions(out, options);
+ * }
+ */
+template<typename STREAM_TYPE>
+STREAM_TYPE& streamInsertRequestAdapterOptions(STREAM_TYPE& out,
+        wgpu::RequestAdapterOptions const& options) noexcept {
    out << "power preference " << powerPreferenceToString(options.powerPreference)
        << " force fallback adapter " << bool(options.forceFallbackAdapter) << " backend type "
        << backendTypeToString(options.backendType);
-    return out.str();
+    return out;
 }

-[[nodiscard]] inline std::string adapterInfoToString(wgpu::AdapterInfo const& info) {
-    std::stringstream out;
+/**
+ * Convenience template to print wgpu::AdapterInfo
+ * @tparam STREAM_TYPE useful namely for streaming to either an utils::io::ostream OR
+ * utils::details::PanicStream, but also for any kind of stream
+ * @param out stream to print to
+ * @param options instance to be printed
+ * @return stream printed to
+ *
+ * Example usage (because including the template operator override itself does not compile):
+ * template<typename STREAM_TYPE>
+ * STREAM_TYPE& operator<<(STREAM_TYPE& out, wgpu::AdapterInfo const& info) noexcept {
+ *   return streamInsertRequestAdapterInfo(out, info);
+ * }
+ */
+template<class STREAM_TYPE>
+STREAM_TYPE& streamInsertRequestAdapterInfo(STREAM_TYPE& out,
+        wgpu::AdapterInfo const& info) noexcept {
    out << "vendor (" << info.vendorID << ") '" << info.vendor
        << "' device (" << info.deviceID << ") '" << info.device
        << "' adapter " << adapterTypeToString(info.adapterType)
@@ -110,7 +162,7 @@ template<typename WebGPUPrintable>
        << " architecture '" << info.architecture
        << "' subgroupMinSize " << info.subgroupMinSize
        << " subgroupMaxSize " << info.subgroupMaxSize;
-    return out.str();
+    return out;
 }

 [[nodiscard]] constexpr std::string_view deviceLostReasonToString(
@@ -123,123 +175,7 @@ template<typename WebGPUPrintable>
    }
 }

-[[nodiscard]] constexpr std::string_view webGPUTextureFormatToString(
-        const wgpu::TextureFormat format) {
-    switch (format) {
-        case wgpu::TextureFormat::Undefined:                   return "Undefined";
-        case wgpu::TextureFormat::R8Unorm:                     return "R8Unorm";
-        case wgpu::TextureFormat::R8Snorm:                     return "R8Snorm";
-        case wgpu::TextureFormat::R8Uint:                      return "R8Uint";
-        case wgpu::TextureFormat::R8Sint:                      return "R8Sint";
-        case wgpu::TextureFormat::R16Uint:                     return "R16Uint";
-        case wgpu::TextureFormat::R16Sint:                     return "R16Sint";
-        case wgpu::TextureFormat::R16Float:                    return "R16Float";
-        case wgpu::TextureFormat::RG8Unorm:                    return "RG8Unorm";
-        case wgpu::TextureFormat::RG8Snorm:                    return "RG8Snorm";
-        case wgpu::TextureFormat::RG8Uint:                     return "RG8Uint";
-        case wgpu::TextureFormat::RG8Sint:                     return "RG8Sint";
-        case wgpu::TextureFormat::R32Float:                    return "R32Float";
-        case wgpu::TextureFormat::R32Uint:                     return "R32Uint";
-        case wgpu::TextureFormat::R32Sint:                     return "R32Sint";
-        case wgpu::TextureFormat::RG16Uint:                    return "RG16Uint";
-        case wgpu::TextureFormat::RG16Sint:                    return "RG16Sint";
-        case wgpu::TextureFormat::RG16Float:                   return "RG16Float";
-        case wgpu::TextureFormat::RGBA8Unorm:                  return "RGBA8Unorm";
-        case wgpu::TextureFormat::RGBA8UnormSrgb:              return "RGBA8UnormSrgb";
-        case wgpu::TextureFormat::RGBA8Snorm:                  return "RGBA8Snorm";
-        case wgpu::TextureFormat::RGBA8Uint:                   return "RGBA8Uint";
-        case wgpu::TextureFormat::RGBA8Sint:                   return "RGBA8Sint";
-        case wgpu::TextureFormat::BGRA8Unorm:                  return "BGRA8Unorm";
-        case wgpu::TextureFormat::BGRA8UnormSrgb:              return "BGRA8UnormSrgb";
-        case wgpu::TextureFormat::RGB10A2Uint:                 return "RGB10A2Uint";
-        case wgpu::TextureFormat::RGB10A2Unorm:                return "RGB10A2Unorm";
-        case wgpu::TextureFormat::RG11B10Ufloat:               return "RG11B10Ufloat";
-        case wgpu::TextureFormat::RGB9E5Ufloat:                return "RGB9E5Ufloat";
-        case wgpu::TextureFormat::RG32Float:                   return "RG32Float";
-        case wgpu::TextureFormat::RG32Uint:                    return "RG32Uint";
-        case wgpu::TextureFormat::RG32Sint:                    return "RG32Sint";
-        case wgpu::TextureFormat::RGBA16Uint:                  return "RGBA16Uint";
-        case wgpu::TextureFormat::RGBA16Sint:                  return "RGBA16Sint";
-        case wgpu::TextureFormat::RGBA16Float:                 return "RGBA16Float";
-        case wgpu::TextureFormat::RGBA32Float:                 return "RGBA32Float";
-        case wgpu::TextureFormat::RGBA32Uint:                  return "RGBA32Uint";
-        case wgpu::TextureFormat::RGBA32Sint:                  return "RGBA32Sint";
-        case wgpu::TextureFormat::Stencil8:                    return "Stencil8";
-        case wgpu::TextureFormat::Depth16Unorm:                return "Depth16Unorm";
-        case wgpu::TextureFormat::Depth24Plus:                 return "Depth24Plus";
-        case wgpu::TextureFormat::Depth24PlusStencil8:         return "Depth24PlusStencil8";
-        case wgpu::TextureFormat::Depth32Float:                return "Depth32Float";
-        case wgpu::TextureFormat::Depth32FloatStencil8:        return "Depth32FloatStencil8";
-        case wgpu::TextureFormat::BC1RGBAUnorm:                return "BC1RGBAUnorm";
-        case wgpu::TextureFormat::BC1RGBAUnormSrgb:            return "BC1RGBAUnormSrgb";
-        case wgpu::TextureFormat::BC2RGBAUnorm:                return "BC2RGBAUnorm";
-        case wgpu::TextureFormat::BC2RGBAUnormSrgb:            return "BC2RGBAUnormSrgb";
-        case wgpu::TextureFormat::BC3RGBAUnorm:                return "BC3RGBAUnorm";
-        case wgpu::TextureFormat::BC3RGBAUnormSrgb:            return "BC3RGBAUnormSrgb";
-        case wgpu::TextureFormat::BC4RUnorm:                   return "BC4RUnorm";
-        case wgpu::TextureFormat::BC4RSnorm:                   return "BC4RSnorm";
-        case wgpu::TextureFormat::BC5RGUnorm:                  return "BC5RGUnorm";
-        case wgpu::TextureFormat::BC5RGSnorm:                  return "BC5RGSnorm";
-        case wgpu::TextureFormat::BC6HRGBUfloat:               return "BC6HRGBUfloat";
-        case wgpu::TextureFormat::BC6HRGBFloat:                return "BC6HRGBFloat";
-        case wgpu::TextureFormat::BC7RGBAUnorm:                return "BC7RGBAUnorm";
-        case wgpu::TextureFormat::BC7RGBAUnormSrgb:            return "BC7RGBAUnormSrgb";
-        case wgpu::TextureFormat::ETC2RGB8Unorm:               return "ETC2RGB8Unorm";
-        case wgpu::TextureFormat::ETC2RGB8UnormSrgb:           return "ETC2RGB8UnormSrgb";
-        case wgpu::TextureFormat::ETC2RGB8A1Unorm:             return "ETC2RGB8A1Unorm";
-        case wgpu::TextureFormat::ETC2RGB8A1UnormSrgb:         return "ETC2RGB8A1UnormSrgb";
-        case wgpu::TextureFormat::ETC2RGBA8Unorm:              return "ETC2RGBA8Unorm";
-        case wgpu::TextureFormat::ETC2RGBA8UnormSrgb:          return "ETC2RGBA8UnormSrgb";
-        case wgpu::TextureFormat::EACR11Unorm:                 return "EACR11Unorm";
-        case wgpu::TextureFormat::EACR11Snorm:                 return "EACR11Snorm";
-        case wgpu::TextureFormat::EACRG11Unorm:                return "EACRG11Unorm";
-        case wgpu::TextureFormat::EACRG11Snorm:                return "EACRG11Snorm";
-        case wgpu::TextureFormat::ASTC4x4Unorm:                return "ASTC4x4Unorm";
-        case wgpu::TextureFormat::ASTC4x4UnormSrgb:            return "ASTC4x4UnormSrgb";
-        case wgpu::TextureFormat::ASTC5x4Unorm:                return "ASTC5x4Unorm";
-        case wgpu::TextureFormat::ASTC5x4UnormSrgb:            return "ASTC5x4UnormSrgb";
-        case wgpu::TextureFormat::ASTC5x5Unorm:                return "ASTC5x5Unorm";
-        case wgpu::TextureFormat::ASTC5x5UnormSrgb:            return "ASTC5x5UnormSrgb";
-        case wgpu::TextureFormat::ASTC6x5Unorm:                return "ASTC6x5Unorm";
-        case wgpu::TextureFormat::ASTC6x5UnormSrgb:            return "ASTC6x5UnormSrgb";
-        case wgpu::TextureFormat::ASTC6x6Unorm:                return "ASTC6x6Unorm";
-        case wgpu::TextureFormat::ASTC6x6UnormSrgb:            return "ASTC6x6UnormSrgb";
-        case wgpu::TextureFormat::ASTC8x5Unorm:                return "ASTC8x5Unorm";
-        case wgpu::TextureFormat::ASTC8x5UnormSrgb:            return "ASTC8x5UnormSrgb";
-        case wgpu::TextureFormat::ASTC8x6Unorm:                return "ASTC8x6Unorm";
-        case wgpu::TextureFormat::ASTC8x6UnormSrgb:            return "ASTC8x6UnormSrgb";
-        case wgpu::TextureFormat::ASTC8x8Unorm:                return "ASTC8x8Unorm";
-        case wgpu::TextureFormat::ASTC8x8UnormSrgb:            return "ASTC8x8UnormSrgb";
-        case wgpu::TextureFormat::ASTC10x5Unorm:               return "ASTC10x5Unorm";
-        case wgpu::TextureFormat::ASTC10x5UnormSrgb:           return "ASTC10x5UnormSrgb";
-        case wgpu::TextureFormat::ASTC10x6Unorm:               return "ASTC10x6Unorm";
-        case wgpu::TextureFormat::ASTC10x6UnormSrgb:           return "ASTC10x6UnormSrgb";
-        case wgpu::TextureFormat::ASTC10x8Unorm:               return "ASTC10x8Unorm";
-        case wgpu::TextureFormat::ASTC10x8UnormSrgb:           return "ASTC10x8UnormSrgb";
-        case wgpu::TextureFormat::ASTC10x10Unorm:              return "ASTC10x10Unorm";
-        case wgpu::TextureFormat::ASTC10x10UnormSrgb:          return "ASTC10x10UnormSrgb";
-        case wgpu::TextureFormat::ASTC12x10Unorm:              return "ASTC12x10Unorm";
-        case wgpu::TextureFormat::ASTC12x10UnormSrgb:          return "ASTC12x10UnormSrgb";
-        case wgpu::TextureFormat::ASTC12x12Unorm:              return "ASTC12x12Unorm";
-        case wgpu::TextureFormat::ASTC12x12UnormSrgb:          return "ASTC12x12UnormSrgb";
-        case wgpu::TextureFormat::R16Unorm:                    return "R16Unorm";
-        case wgpu::TextureFormat::RG16Unorm:                   return "RG16Unorm";
-        case wgpu::TextureFormat::RGBA16Unorm:                 return "RGBA16Unorm";
-        case wgpu::TextureFormat::R16Snorm:                    return "R16Snorm";
-        case wgpu::TextureFormat::RG16Snorm:                   return "RG16Snorm";
-        case wgpu::TextureFormat::RGBA16Snorm:                 return "RGBA16Snorm";
-        case wgpu::TextureFormat::R8BG8Biplanar420Unorm:       return "R8BG8Biplanar420Unorm";
-        case wgpu::TextureFormat::R10X6BG10X6Biplanar420Unorm: return "R10X6BG10X6Biplanar420Unorm";
-        case wgpu::TextureFormat::R8BG8A8Triplanar420Unorm:    return "R8BG8A8Triplanar420Unorm";
-        case wgpu::TextureFormat::R8BG8Biplanar422Unorm:       return "R8BG8Biplanar422Unorm";
-        case wgpu::TextureFormat::R8BG8Biplanar444Unorm:       return "R8BG8Biplanar444Unorm";
-        case wgpu::TextureFormat::R10X6BG10X6Biplanar422Unorm: return "R10X6BG10X6Biplanar422Unorm";
-        case wgpu::TextureFormat::R10X6BG10X6Biplanar444Unorm: return "R10X6BG10X6Biplanar444Unorm";
-        case wgpu::TextureFormat::External:                    return "External";
-    }
-}
-
-[[nodiscard]] constexpr std::string_view filamentShaderStageToString(const ShaderStage stage) {
+[[nodiscard]] constexpr std::string_view filamentShaderStageToString(ShaderStage stage) {
    switch (stage) {
        case ShaderStage::VERTEX:   return "vertex";
        case ShaderStage::FRAGMENT: return "fragment";
@@ -24,25 +24,43 @@
 #include "backend/DriverEnums.h"

 #include <utils/Panic.h>
+#include <utils/ostream.h>

 #include <webgpu/webgpu_cpp.h>

 #include <algorithm>
 #include <cstdint>

-namespace filament::backend {
-
 namespace {

 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
+utils::io::ostream& operator<<(utils::io::ostream& out, const wgpu::TextureFormat format) noexcept {
+    return filament::backend::streamInsertWebGPUPrintable(out, format);
+}
+
+utils::io::ostream& operator<<(utils::io::ostream& out,
+        const wgpu::TextureUsage textureUsage) noexcept {
+    return filament::backend::streamInsertWebGPUPrintable(out, textureUsage);
+}
+
+utils::io::ostream& operator<<(utils::io::ostream& out,
+        const wgpu::PresentMode presentMode) noexcept {
+    return filament::backend::streamInsertWebGPUPrintable(out, presentMode);
+}
+
+utils::io::ostream& operator<<(utils::io::ostream& out,
+        const wgpu::CompositeAlphaMode alphaMode) noexcept {
+    return filament::backend::streamInsertWebGPUPrintable(out, alphaMode);
+}
+
 void printSurfaceCapabilitiesDetails(wgpu::SurfaceCapabilities const& capabilities) {
    FWGPU_LOGI << "WebGPU surface capabilities:";
-    FWGPU_LOGI << "  surface usages: " << webGPUPrintableToString(capabilities.usages);
+    FWGPU_LOGI << "  surface usages: " << capabilities.usages;
    FWGPU_LOGI << "  surface formats (" << capabilities.formatCount << "):";
    if (capabilities.formatCount > 0 && capabilities.formats != nullptr) {
        std::for_each(capabilities.formats, capabilities.formats + capabilities.formatCount,
                [](wgpu::TextureFormat const format) {
-                    FWGPU_LOGI << "    " << webGPUTextureFormatToString(format);
+                    FWGPU_LOGI << "    " << format;
                });
    }
    FWGPU_LOGI << "  surface present modes (" << capabilities.presentModeCount << "):";
@@ -50,7 +68,7 @@ void printSurfaceCapabilitiesDetails(wgpu::SurfaceCapabilities const& capabiliti
        std::for_each(capabilities.presentModes,
                capabilities.presentModes + capabilities.presentModeCount,
                [](wgpu::PresentMode const presentMode) {
-                    FWGPU_LOGI << "    " << webGPUPrintableToString(presentMode);
+                    FWGPU_LOGI << "    " << presentMode;
                });
    }
    FWGPU_LOGI << "  surface alpha modes (" << capabilities.alphaModeCount << "):";
@@ -58,7 +76,7 @@ void printSurfaceCapabilitiesDetails(wgpu::SurfaceCapabilities const& capabiliti
        std::for_each(capabilities.alphaModes,
                capabilities.alphaModes + capabilities.alphaModeCount,
                [](wgpu::CompositeAlphaMode const alphaMode) {
-                    FWGPU_LOGI << "    " << webGPUPrintableToString(alphaMode);
+                    FWGPU_LOGI << "    " << alphaMode;
                });
    }
 }
@@ -66,20 +84,20 @@ void printSurfaceCapabilitiesDetails(wgpu::SurfaceCapabilities const& capabiliti
 void printSurfaceConfiguration(wgpu::SurfaceConfiguration const& config,
        wgpu::TextureFormat depthFormat) {
    FWGPU_LOGI << "WebGPU surface configuration:";
-    FWGPU_LOGI << "  surface format: " << webGPUTextureFormatToString(config.format);
-    FWGPU_LOGI << "  surface usage: " << webGPUPrintableToString(config.usage);
+    FWGPU_LOGI << "  surface format: " << config.format;
+    FWGPU_LOGI << "  surface usage: " << config.usage;
    FWGPU_LOGI << "  surface view formats (" << config.viewFormatCount << "):";
    if (config.viewFormatCount > 0 && config.viewFormats != nullptr) {
        std::for_each(config.viewFormats, config.viewFormats + config.viewFormatCount,
                [](wgpu::TextureFormat const viewFormat) {
-                    FWGPU_LOGI << "    " << webGPUPrintableToString(viewFormat);
+                    FWGPU_LOGI << "    " << viewFormat;
                });
    }
-    FWGPU_LOGI << "  surface alpha mode: " << webGPUPrintableToString(config.alphaMode);
+    FWGPU_LOGI << "  surface alpha mode: " << config.alphaMode;
    FWGPU_LOGI << "  surface width: " << config.width;
    FWGPU_LOGI << "  surface height: " << config.height;
-    FWGPU_LOGI << "  surface present mode: " << webGPUPrintableToString(config.presentMode);
-    FWGPU_LOGI << "WebGPU selected depth format: " << webGPUTextureFormatToString(depthFormat);
+    FWGPU_LOGI << "  surface present mode: " << config.presentMode;
+    FWGPU_LOGI << "WebGPU selected depth format: " << depthFormat;
 }
 #endif// FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)

@@ -110,6 +128,7 @@ void printSurfaceConfiguration(wgpu::SurfaceConfiguration const& config,
            return wgpu::TextureFormat::Depth24PlusStencil8;
        }
    } else {
+        // other options: Depth16Unorm or Depth24Plus
        return wgpu::TextureFormat::Depth32Float;
    }
 }
@@ -216,9 +235,10 @@ void initConfig(wgpu::SurfaceConfiguration& config, wgpu::Device const& device,
 }

 [[nodiscard]] wgpu::TextureView createDepthTextureView(wgpu::Texture const& depthTexture,
-        wgpu::TextureFormat const& depthFormat, bool const needStencil) {
+        wgpu::TextureFormat depthFormat, bool needStencil) {
    wgpu::TextureViewDescriptor descriptor{
        .label = "depth_texture_view",
+        .format = depthFormat,
        .dimension = wgpu::TextureViewDimension::e2D,
        .baseMipLevel = 0,
        .mipLevelCount = 1,
@@ -229,16 +249,6 @@ void initConfig(wgpu::SurfaceConfiguration& config, wgpu::Device const& device,
    };
    if (needStencil) {
        descriptor.aspect = wgpu::TextureAspect::All;
-        descriptor.format = depthFormat;
-    } else {
-        descriptor.aspect = wgpu::TextureAspect::DepthOnly;
-        if (depthFormat == wgpu::TextureFormat::Depth32FloatStencil8) {
-            descriptor.format = wgpu::TextureFormat::Depth32Float;
-        } else if (depthFormat == wgpu::TextureFormat::Depth24PlusStencil8) {
-            descriptor.format = wgpu::TextureFormat::Depth24Plus;
-        } else {
-            descriptor.format = depthFormat;
-        }
    }
    wgpu::TextureView depthTextureView = depthTexture.CreateView(&descriptor);
    FILAMENT_CHECK_POSTCONDITION(depthTextureView) << "Failed to create depth texture view";
@@ -247,6 +257,8 @@ void initConfig(wgpu::SurfaceConfiguration& config, wgpu::Device const& device,

 }// namespace

+namespace filament::backend {
+
 WebGPUSwapChain::WebGPUSwapChain(wgpu::Surface&& surface, wgpu::Extent2D const& surfaceSize,
        wgpu::Adapter const& adapter, wgpu::Device const& device, uint64_t flags)
    : mDevice(device),
@@ -17,8 +17,6 @@
 #include "WebGPUTexture.h"

 #include "WebGPUConstants.h"
-#include "WebGPURenderPassMipmapGenerator.h"
-#include "WebGPUStrings.h"

 #include "DriverBase.h"
 #include "private/backend/BackendUtils.h"
@@ -27,6 +25,7 @@
 #include <utils/BitmaskEnum.h>
 #include <utils/Panic.h>
 #include <utils/debug.h>
+#include <utils/ostream.h>

 #include <webgpu/webgpu_cpp.h>
 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
@@ -142,13 +141,10 @@ namespace {
 * @param samples How many samples to use for MSAA
 * @param needsComputeStorageSupport if we need to use this texture as storage binding in something
 *                                   like a compute shader
- * @param needsRenderAttachmentSupport if we need to use this texture as a render pass attachment
- *                                     in something like a render pass blit (e.g. mipmap generation)
 * @return The appropriate texture usage flags for the underlying texture
 */
 [[nodiscard]] wgpu::TextureUsage fToWGPUTextureUsage(TextureUsage const& fUsage,
-        const uint8_t samples, const bool needsComputeStorageSupport,
-        const bool needsRenderAttachmentSupport) {
+        const uint8_t samples, const bool needsComputeStorageSupport) {
    wgpu::TextureUsage retUsage = wgpu::TextureUsage::None;

    // if needsComputeStorageSupport we need to read and write to the texture in a shader and thus
@@ -169,16 +165,6 @@ namespace {
    if (needsComputeStorageSupport) {
        retUsage |= wgpu::TextureUsage::StorageBinding;
    }
-    if (needsRenderAttachmentSupport) {
-        retUsage |= wgpu::TextureUsage::RenderAttachment;
-    }
-    if (any(TextureUsage::BLIT_SRC & fUsage)) {
-        retUsage |= wgpu::TextureUsage::RenderAttachment;
-    }
-    if (any(TextureUsage::BLIT_DST & fUsage)) {
-        retUsage |= wgpu::TextureUsage::RenderAttachment;
-        retUsage |= wgpu::TextureUsage::TextureBinding;
-    }
    // WGPU Render attachment covers either color or stencil situation dependant
    // NOTE: Depth attachment isn't used this way in Vulkan but logically maps to WGPU docs. If
    // issues, investigate here.
@@ -273,26 +259,6 @@ namespace {
    }
 }

-[[nodiscard]] WebGPUTexture::MipmapGenerationStrategy determineMipmapGenerationStrategy(
-        const wgpu::TextureFormat format, const SamplerType samplerType, const uint8_t sampleCount,
-        const uint8_t mipmapLevels) {
-    if (mipmapLevels <= 1) {
-        return WebGPUTexture::MipmapGenerationStrategy::NONE; // no mipmap generation needed
-    }
-    const WebGPURenderPassMipmapGenerator::FormatCompatibility renderPassCompatibility{
-        WebGPURenderPassMipmapGenerator::getCompatibilityFor(format,
-                toWebGPUTextureDimension(samplerType), sampleCount)
-    };
-    if (renderPassCompatibility.compatible) {
-        return WebGPUTexture::MipmapGenerationStrategy::RENDER_PASS;
-    }
-    if (WebGPUTexture::supportsMultipleMipLevelsViaStorageBinding(format)) {
-        return WebGPUTexture::MipmapGenerationStrategy::SPD_COMPUTE_PASS;
-    }
-    // we don't have a way to generate mipmaps for this texture, at least at this time
-    return WebGPUTexture::MipmapGenerationStrategy::NONE;
-}
-
 [[nodiscard]] constexpr wgpu::Extent3D toTextureSize(const SamplerType samplerType,
        const uint32_t width, const uint32_t height, const uint32_t depth) {
    switch (samplerType) {
@@ -330,17 +296,14 @@ WebGPUTexture::WebGPUTexture(const SamplerType samplerType, const uint8_t levels
        wgpu::Device const& device) noexcept
    : HwTexture{ samplerType, levels, samples, width, height, depth, format, usage },
      mViewFormat{ fToWGPUTextureFormat(format) },
-      mMipmapGenerationStrategy{ determineMipmapGenerationStrategy(mViewFormat, samplerType,
-              samples, levels) },
-      mWebGPUFormat{ mMipmapGenerationStrategy == MipmapGenerationStrategy::SPD_COMPUTE_PASS
+      mSupportsMultipleMipLevels{ levels > 1 &&
+                                  supportsMultipleMipLevelsViaStorageBinding(mViewFormat) },
+      mWebGPUFormat{ mSupportsMultipleMipLevels
                             ? storageBindingCompatibleFormatForViewFormat(mViewFormat)
                             : mViewFormat },
      mAspect{ fToWGPUTextureViewAspect(usage, format) },
-      mWebGPUUsage{ fToWGPUTextureUsage(usage, samples,
-              mMipmapGenerationStrategy == MipmapGenerationStrategy::SPD_COMPUTE_PASS,
-              mMipmapGenerationStrategy == MipmapGenerationStrategy::RENDER_PASS) },
-      mViewUsage{ fToWGPUTextureUsage(usage, samples, false, false) },
-      mDimension{toWebGPUTextureViewDimension(samplerType)},
+      mWebGPUUsage{ fToWGPUTextureUsage(usage, samples, mSupportsMultipleMipLevels) },
+      mViewUsage{ fToWGPUTextureUsage(usage, samples, false) },
      mBlockWidth{ filament::backend::getBlockWidth(format) },
      mBlockHeight{ filament::backend::getBlockHeight(format) },
      mDefaultMipLevel{ 0 },
@@ -380,7 +343,8 @@ WebGPUTexture::WebGPUTexture(const SamplerType samplerType, const uint8_t levels
        std::stringstream textureFormatStream;
        textureFormatStream << mWebGPUFormat;
        FWGPU_LOGD << "Texture '" << textureDescriptor.label << "' has view format "
-                   << viewFormatStream.str() << " and texture format " << textureFormatStream.str();
+                   << viewFormatStream.str() << " and texture format " << textureFormatStream.str()
+                   << utils::io::endl;
    }
 #endif
 }
@@ -390,7 +354,7 @@ WebGPUTexture::WebGPUTexture(WebGPUTexture const* src, const uint8_t baseLevel,
    : HwTexture{ src->target, levelCount, src->samples, src->width, src->height, src->depth,
          src->format, src->usage },
      mViewFormat{ src->mViewFormat },
-      mMipmapGenerationStrategy{ src->mMipmapGenerationStrategy },
+      mSupportsMultipleMipLevels{ src->mSupportsMultipleMipLevels },
      mWebGPUFormat{ src->mWebGPUFormat },
      mAspect{ src->mAspect },
      mWebGPUUsage{ src->mWebGPUUsage },
@@ -402,21 +366,7 @@ WebGPUTexture::WebGPUTexture(WebGPUTexture const* src, const uint8_t baseLevel,
      mDefaultMipLevel{ baseLevel },
      mDefaultBaseArrayLayer{ src->mArrayLayerCount },
      mDefaultTextureView{ makeTextureView(mDefaultMipLevel, levelCount, 0, mDefaultBaseArrayLayer,
-              src->target) },
-      mMsaaSidecarTexture{ src->mMsaaSidecarTexture } {}
-
-wgpu::Texture const& WebGPUTexture::getMsaaSidecarTexture(const uint8_t sampleCount) const {
-    if (mMsaaSidecarTexture == nullptr) {
-        return mMsaaSidecarTexture; // nullptr (no such sidecar)
-    }
-    FILAMENT_CHECK_PRECONDITION(sampleCount == mMsaaSidecarTexture.GetSampleCount())
-            << "The MSAA sidecar texture has a different sample count ("
-            << mMsaaSidecarTexture.GetSampleCount() << ") than requested (" << +sampleCount
-            << "). Note that this restriction was written when WebGPU only supported msaa "
-               "textures with 4 samples. If that has changed, this implementation should be "
-               "updated (e.g. map of sidecar textures by sampleCount or something).";
-    return mMsaaSidecarTexture;
-}
+              src->target) } {}

 bool WebGPUTexture::supportsMultipleMipLevelsViaStorageBinding(const wgpu::TextureFormat format) {
    return storageBindingCompatibleFormatForViewFormat(format) != wgpu::TextureFormat::Undefined;
@@ -431,68 +381,6 @@ wgpu::TextureView WebGPUTexture::getOrMakeTextureView(const uint8_t mipLevel,
    return makeTextureView(mipLevel, 1, arrayLayer, 1, target);
 }

-void WebGPUTexture::createMsaaSidecarTextureIfNotAlreadyCreated(const uint8_t samples,
-        wgpu::Device const& device) {
-    FILAMENT_CHECK_PRECONDITION(samples > 1) << "Requesting to create a MSAA sidecar texture for "
-                                             << +samples << " samples? Invalid request.";
-    if (mMsaaSidecarTexture) {
-        FILAMENT_CHECK_PRECONDITION(mMsaaSidecarTexture.GetSampleCount() == samples)
-                << "An MSAA sidecar texture has already been created for this texture, but with a "
-                   "different sample count ("
-                << mMsaaSidecarTexture.GetSampleCount() << ") than requested (" << +samples
-                << "). Note that this restriction was written when WebGPU only supported msaa "
-                   "textures with 4 samples. If that has changed, this implementation should be "
-                   "updated (e.g. map of sidecar textures by sampleCount or something).";
-        return; // we already have the sidecar created
-    }
-    const wgpu::TextureDescriptor descriptor{
-        .label = "msaa_sidecar_texture",
-        .usage = mTexture.GetUsage(),
-        .dimension = mTexture.GetDimension(),
-        .size = {
-            .width = mTexture.GetWidth(),
-            .height = mTexture.GetHeight(),
-            .depthOrArrayLayers = mTexture.GetDepthOrArrayLayers(),
-        },
-        .format = mTexture.GetFormat(),
-        .mipLevelCount = mTexture.GetMipLevelCount(),
-        .sampleCount = samples,
-        .viewFormatCount = 1,
-        .viewFormats = &mViewFormat,
-    };
-    mMsaaSidecarTexture = device.CreateTexture(&descriptor);
-    FILAMENT_CHECK_POSTCONDITION(mMsaaSidecarTexture) << "Failed to create MSAA sidecar texture";
-}
-
-wgpu::TextureView WebGPUTexture::makeMsaaSidecarTextureViewIfTextureSidecarExists(
-        const uint8_t samples, const uint8_t mipLevel, const uint32_t arrayLayer) const {
-    if (mMsaaSidecarTexture == nullptr) {
-        return nullptr;
-    }
-    FILAMENT_CHECK_PRECONDITION(mMsaaSidecarTexture.GetSampleCount() == samples)
-            << "An MSAA sidecar texture has already been created for this texture, but with a "
-               "different sample count ("
-            << mMsaaSidecarTexture.GetSampleCount() << ") than requested for view (" << +samples
-            << "). Note that this restriction was written when WebGPU only supported msaa "
-               "textures with 4 samples. If that has changed, this implementation should be "
-               "updated (e.g. map of sidecar textures by sampleCount or something).";
-    const wgpu::TextureViewDescriptor descriptor{
-        .label = "msaa_sidecar_texture_view",
-        .format = mViewFormat,
-        .dimension = mDimension,
-        .baseMipLevel = mipLevel,
-        .mipLevelCount = 1,
-        .baseArrayLayer = arrayLayer,
-        .arrayLayerCount = 1,
-        .aspect = mAspect,
-        .usage = mViewUsage,
-    };
-    const wgpu::TextureView textureView{ mMsaaSidecarTexture.CreateView(&descriptor) };
-    FILAMENT_CHECK_POSTCONDITION(mMsaaSidecarTexture)
-            << "Failed to create MSAA sidecar texture view (" << +samples << " samples)";
-    return textureView;
-}
-
 wgpu::TextureFormat WebGPUTexture::fToWGPUTextureFormat(TextureFormat const& fFormat) {
    switch (fFormat) {
        case TextureFormat::R8:                      return wgpu::TextureFormat::R8Unorm;
@@ -582,43 +470,51 @@ wgpu::TextureFormat WebGPUTexture::fToWGPUTextureFormat(TextureFormat const& fFo
            // No direct mapping in wgpu. Could potentially map to RGBA8Unorm
            // and discard the alpha and lower precision.
            FWGPU_LOGW << "Requested Filament texture format RGB565 but getting "
-                          "wgpu::TextureFormat::Undefined (no direct mapping in wgpu)";
+                          "wgpu::TextureFormat::Undefined (no direct mapping in wgpu)"
+                       << utils::io::endl;
            return wgpu::TextureFormat::Undefined;
        case TextureFormat::RGB9_E5: return wgpu::TextureFormat::RGB9E5Ufloat;
        case TextureFormat::RGB5_A1:
            // No direct mapping in wgpu. Could potentially map to RGBA8Unorm
            // and handle the packing/unpacking in shaders.
            FWGPU_LOGW << "Requested Filament texture format RGB5_A1 but getting "
-                          "wgpu::TextureFormat::Undefined (no direct mapping in wgpu)";
+                          "wgpu::TextureFormat::Undefined (no direct mapping in wgpu)"
+                       << utils::io::endl;
            return wgpu::TextureFormat::Undefined;
        case TextureFormat::RGBA4:
            // No direct mapping in wgpu. Could potentially map to RGBA8Unorm
            // and handle the packing/unpacking in shaders.
            FWGPU_LOGW << "Requested Filament texture format RGBA4 but getting "
-                          "wgpu::TextureFormat::Undefined (no direct mapping in wgpu)";
+                          "wgpu::TextureFormat::Undefined (no direct mapping in wgpu)"
+                       << utils::io::endl;
            return wgpu::TextureFormat::Undefined;
        case TextureFormat::RGB8:
            FWGPU_LOGW << "Requested Filament texture format RGB8 but getting "
                          "wgpu::TextureFormat::RGBA8Unorm (no direct sRGB equivalent in wgpu "
-                          "without alpha)";
+                          "without alpha)"
+                       << utils::io::endl;
            return wgpu::TextureFormat::RGBA8Unorm;
        case TextureFormat::SRGB8:
            FWGPU_LOGW << "Requested Filament texture format SRGB8 but getting "
                          "wgpu::TextureFormat::RGBA8UnormSrgb (no direct sRGB equivalent in wgpu "
-                          "without alpha)";
+                          "without alpha)"
+                       << utils::io::endl;
            return wgpu::TextureFormat::RGBA8UnormSrgb;
        case TextureFormat::RGB8_SNORM:
            FWGPU_LOGW
                    << "Requested Filament texture format RGB8_SNORM but getting "
-                       "wgpu::TextureFormat::RGBA8Snorm (no direct mapping in wgpu without alpha)";
+                       "wgpu::TextureFormat::RGBA8Snorm (no direct mapping in wgpu without alpha)"
+                    << utils::io::endl;
            return wgpu::TextureFormat::RGBA8Snorm;
        case TextureFormat::RGB8UI:
            FWGPU_LOGW << "Requested Filament texture format RGB8UI but getting "
-                          "wgpu::TextureFormat::RGBA8Uint (no direct mapping in wgpu without alpha)";
+                          "wgpu::TextureFormat::RGBA8Uint (no direct mapping in wgpu without alpha)"
+                       << utils::io::endl;
            return wgpu::TextureFormat::RGBA8Uint;
        case TextureFormat::RGB8I:
            FWGPU_LOGW << "Requested Filament texture format RGB8I but getting "
-                          "wgpu::TextureFormat::RGBA8Sint (no direct mapping in wgpu without alpha)";
+                          "wgpu::TextureFormat::RGBA8Sint (no direct mapping in wgpu without alpha)"
+                       << utils::io::endl;
            return wgpu::TextureFormat::RGBA8Sint;
        case TextureFormat::R11F_G11F_B10F:          return wgpu::TextureFormat::RG11B10Ufloat;
        case TextureFormat::UNUSED:                  return wgpu::TextureFormat::Undefined;
@@ -626,32 +522,38 @@ wgpu::TextureFormat WebGPUTexture::fToWGPUTextureFormat(TextureFormat const& fFo
        case TextureFormat::RGB16F:
            FWGPU_LOGW
                    << "Requested Filament texture format RGB16F but getting "
-                       "wgpu::TextureFormat::RGBA16Float (no direct mapping in wgpu without alpha)";
+                       "wgpu::TextureFormat::RGBA16Float (no direct mapping in wgpu without alpha)"
+                    << utils::io::endl;
            return wgpu::TextureFormat::RGBA16Float;
        case TextureFormat::RGB16UI:
            FWGPU_LOGW
                    << "Requested Filament texture format RGB16UI but getting "
-                       "wgpu::TextureFormat::RGBA16Uint (no direct mapping in wgpu without alpha)";
+                       "wgpu::TextureFormat::RGBA16Uint (no direct mapping in wgpu without alpha)"
+                    << utils::io::endl;
            return wgpu::TextureFormat::RGBA16Uint;
        case TextureFormat::RGB16I:
            FWGPU_LOGW
                    << "Requested Filament texture format RGB16I but getting "
-                       "wgpu::TextureFormat::RGBA16Sint (no direct mapping in wgpu without alpha)";
+                       "wgpu::TextureFormat::RGBA16Sint (no direct mapping in wgpu without alpha)"
+                    << utils::io::endl;
            return wgpu::TextureFormat::RGBA16Sint;
        case TextureFormat::RGB32F:
            FWGPU_LOGW
                    << "Requested Filament texture format RGB32F but getting "
-                       "wgpu::TextureFormat::RGBA32Float (no direct mapping in wgpu without alpha)";
+                       "wgpu::TextureFormat::RGBA32Float (no direct mapping in wgpu without alpha)"
+                    << utils::io::endl;
            return wgpu::TextureFormat::RGBA32Float;
        case TextureFormat::RGB32UI:
            FWGPU_LOGW
                    << "Requested Filament texture format RGB32UI but getting "
-                       "wgpu::TextureFormat::RGBA32Uint (no direct mapping in wgpu without alpha)";
+                       "wgpu::TextureFormat::RGBA32Uint (no direct mapping in wgpu without alpha)"
+                    << utils::io::endl;
            return wgpu::TextureFormat::RGBA32Uint;
        case TextureFormat::RGB32I:
            FWGPU_LOGW
                    << "Requested Filament texture format RGB32I but getting "
-                       "wgpu::TextureFormat::RGBA32Sint (no direct mapping in wgpu without alpha)";
+                       "wgpu::TextureFormat::RGBA32Sint (no direct mapping in wgpu without alpha)"
+                    << utils::io::endl;
            return wgpu::TextureFormat::RGBA32Sint;
        case TextureFormat::DXT1_RGB:                return wgpu::TextureFormat::BC1RGBAUnorm;
        case TextureFormat::DXT1_RGBA:               return wgpu::TextureFormat::BC1RGBAUnorm;
@@ -667,6 +569,13 @@ wgpu::TextureFormat WebGPUTexture::fToWGPUTextureFormat(TextureFormat const& fFo
 wgpu::TextureView WebGPUTexture::makeTextureView(const uint8_t& baseLevel,
        const uint8_t& levelCount, const uint32_t& baseArrayLayer, const uint32_t& arrayLayerCount,
        const SamplerType samplerType) const noexcept {
+#if FWGPU_ENABLED(FWGPU_DEBUG_VALIDATION)
+    if (baseLevel > 0 && !mSupportsMultipleMipLevels) {
+        FWGPU_LOGW << "Trying to make a texture view into a level ("
+                   << static_cast<uint32_t>(baseLevel)
+                   << ") for which we cannot generate mip levels." << utils::io::endl;
+    }
+#endif
    const wgpu::TextureViewDescriptor textureViewDescriptor{
        .label = getUserTextureViewLabel(target),
        .format = mViewFormat,
@@ -26,28 +26,8 @@

 namespace filament::backend {

-[[nodiscard]] constexpr bool hasStencil(const wgpu::TextureFormat textureFormat) {
-    return textureFormat == wgpu::TextureFormat::Depth24PlusStencil8 ||
-           textureFormat == wgpu::TextureFormat::Depth32FloatStencil8 ||
-           textureFormat == wgpu::TextureFormat::Stencil8;
-}
-
-[[nodiscard]] constexpr bool hasDepth(const wgpu::TextureFormat textureFormat) {
-    return textureFormat == wgpu::TextureFormat::Depth16Unorm ||
-           textureFormat == wgpu::TextureFormat::Depth32Float ||
-           textureFormat == wgpu::TextureFormat::Depth24Plus ||
-           textureFormat == wgpu::TextureFormat::Depth24PlusStencil8 ||
-           textureFormat == wgpu::TextureFormat::Depth32FloatStencil8;
-}
-
 class WebGPUTexture : public HwTexture {
 public:
-    enum class MipmapGenerationStrategy : uint8_t {
-        RENDER_PASS,
-        SPD_COMPUTE_PASS,
-        NONE,
-    };
-
    WebGPUTexture(SamplerType, uint8_t levels, TextureFormat, uint8_t samples, uint32_t width,
            uint32_t height, uint32_t depth, TextureUsage, wgpu::Device const&) noexcept;

@@ -61,49 +41,17 @@ public:

    [[nodiscard]] wgpu::Texture const& getTexture() const { return mTexture; }

-    [[nodiscard]] wgpu::Texture const& getMsaaSidecarTexture(uint8_t sampleCount) const;
-
    [[nodiscard]] wgpu::TextureView const& getDefaultTextureView() const {
        return mDefaultTextureView;
    }

    [[nodiscard]] wgpu::TextureView getOrMakeTextureView(uint8_t mipLevel, uint32_t arrayLayer);

-    [[nodiscard]] wgpu::TextureViewDimension getViewDimension() const { return mDimension; }
    [[nodiscard]] wgpu::TextureFormat getViewFormat() const { return mViewFormat; }

    [[nodiscard]] uint32_t getArrayLayerCount() const { return mArrayLayerCount; }

-    [[nodiscard]] MipmapGenerationStrategy getMipmapGenerationStrategy() const {
-        return mMipmapGenerationStrategy;
-    }
-
-    /**
-     * Creates the MSAA sidecar texture if it has not already been created.
-     * If the sidecar already exists with a different number of samples this will panic
-     * (at the time of writing this WebGPU only supports MSAA with 4 samples. If this changes, then
-     * multiple sidecars with different number of samples could be supported if needed, but that
-     * level of complexity is not warranted at this time).
-     * Additionally, if samples is <= 1 this will panic as well, as that is not an MSAA texture.
-     * @param samples The number of samples the texture will have
-     */
-    void createMsaaSidecarTextureIfNotAlreadyCreated(uint8_t samples, wgpu::Device const&);
-
-    /**
-     * @param samples The number of samples the underlying texture supports
-     * @param mipLevel The mip level into the underyling texture for which this view will reference
-     * (this view will only have one mip level)
-     * @param arrayLayer The layer into the underyling texture for which this view will reference
-     * (this view will only have one layer)
-     * @return A texture view for the MSAA sidecar texture
-     */
-    wgpu::TextureView makeMsaaSidecarTextureViewIfTextureSidecarExists(uint8_t samples,
-            uint8_t mipLevel, uint32_t arrayLayer) const;
-
-    /**
-     * @return nullptr if a MSAA sidecar texture is not appliable, otherwise a view to one
-     */
-    [[nodiscard]] wgpu::TextureView makeMsaaSidecarTextureView(wgpu::Texture const&, uint8_t mipLevel, uint32_t arrayLayer) const;
+    [[nodiscard]] bool supportsMultipleMipLevels() const { return mSupportsMultipleMipLevels; }

    [[nodiscard]] static wgpu::TextureFormat fToWGPUTextureFormat(
            filament::backend::TextureFormat const& fFormat);
@@ -123,7 +71,8 @@ private:
    // certain formats (e.g. compute shaders), but we need a view to that format elsewhere
    // (e.g. another shader or render target)
    wgpu::TextureFormat mViewFormat = wgpu::TextureFormat::Undefined;
-    MipmapGenerationStrategy mMipmapGenerationStrategy = MipmapGenerationStrategy::NONE;
+    // this is true IFF levels > 1 AND we can actually generate mipmaps for the texture
+    bool mSupportsMultipleMipLevels = false;
    // format is inherited from HwTexture. This naming is to distinguish it from Filament's format
    // this is the underlying texture's format, not necessarily the "view" of it... see mViewFormat
    wgpu::TextureFormat mWebGPUFormat = wgpu::TextureFormat::Undefined;
@@ -131,7 +80,6 @@ private:
    // usage is inherited from HwTexture. This naming is to distinguish it from Filament's usage
    wgpu::TextureUsage mWebGPUUsage = wgpu::TextureUsage::None;
    wgpu::TextureUsage mViewUsage = wgpu::TextureUsage::None;
-    wgpu::TextureViewDimension mDimension = wgpu::TextureViewDimension::Undefined;
    size_t mBlockWidth = 0;
    size_t mBlockHeight = 0;
    uint32_t mArrayLayerCount = 1;
@@ -139,11 +87,6 @@ private:
    uint32_t mDefaultMipLevel = 0;
    uint32_t mDefaultBaseArrayLayer = 0;
    wgpu::TextureView mDefaultTextureView = nullptr;
-    // At the time of writing this, WebGPU only supported 4 samples in a multi-sampled texture.
-    // If that has changed, then consider updating the implementation to have a map of msaa textures
-    // by sampleCount or something like that.
-    // For now that complexity and cost is not warranted due to WebGPU's restrictions.
-    wgpu::Texture mMsaaSidecarTexture = nullptr;

    [[nodiscard]] wgpu::TextureView makeTextureView(const uint8_t& baseLevel,
            const uint8_t& levelCount, const uint32_t& baseArrayLayer,
@@ -22,6 +22,7 @@
 #include <backend/DriverEnums.h>

 #include <utils/Panic.h>
+#include <utils/ostream.h>

 #include <webgpu/webgpu_cpp.h>

@@ -56,22 +57,26 @@ namespace {
            case ElementType::BYTE3:
                FWGPU_LOGW
                        << "Requested Filament vertex format BYTE3 (normalized) but getting "
-                           "wgpu::VertexFormat::Snorm8x4 (no direct mapping in wgpu for x3 byte)";
+                           "wgpu::VertexFormat::Snorm8x4 (no direct mapping in wgpu for x3 byte)"
+                        << utils::io::endl;
                return VertexFormat::Snorm8x4; // NOT MINSPEC
            case ElementType::UBYTE3:
                FWGPU_LOGW
                        << "Requested Filament vertex format UBYTE3 (normalized) but getting "
-                           "wgpu::VertexFormat::Unorm8x4 (no direct mapping in wgpu for x3 byte)";
+                           "wgpu::VertexFormat::Unorm8x4 (no direct mapping in wgpu for x3 byte)"
+                        << utils::io::endl;
                return VertexFormat::Unorm8x4; // NOT MINSPEC
            case ElementType::SHORT3:
                FWGPU_LOGW << "Requested Filament vertex format SHORT3 (normalized) but getting "
                              "wgpu::VertexFormat::Snorm16x4 (no direct mapping in wgpu for x3 "
-                              "half/short)";
+                              "half/short)"
+                           << utils::io::endl;
                return VertexFormat::Snorm16x4; // NOT MINSPEC
            case ElementType::USHORT3:
                FWGPU_LOGW << "Requested Filament vertex format USHORT3 (normalized) but getting "
                              "wgpu::VertexFormat::Unorm16x4 (no direct mapping in wgpu for x3 "
-                              "half/short)";
+                              "half/short)"
+                           << utils::io::endl;
                return VertexFormat::Unorm16x4; // NOT MINSPEC
            // Four Component Types
            case ElementType::BYTE4:   return VertexFormat::Snorm8x4;
@@ -92,22 +97,26 @@ namespace {
        case ElementType::BYTE:
            if (integer) return VertexFormat::Sint8;
            FWGPU_LOGW << "Requested Filament vertex format BYTE (float) but getting "
-                          "wgpu::VertexFormat::Float16 (no direct mapping in wgpu for 8 bit float)";
+                          "wgpu::VertexFormat::Float16 (no direct mapping in wgpu for 8 bit float)"
+                       << utils::io::endl;
            return wgpu::VertexFormat::Float16;
        case ElementType::UBYTE:
            if (integer) return VertexFormat::Uint8;
            FWGPU_LOGW << "Requested Filament vertex format UBYTE (float) but getting "
-                          "wgpu::VertexFormat::Float16 (no direct mapping in wgpu for 8 bit float)";
+                          "wgpu::VertexFormat::Float16 (no direct mapping in wgpu for 8 bit float)"
+                       << utils::io::endl;
            return VertexFormat::Float16;
        case ElementType::SHORT:
            if (integer) return VertexFormat::Sint16;
            FWGPU_LOGW << "Requested Filament vertex format SHORT (float) and getting "
-                          "wgpu::VertexFormat::Float16 (potential loss of precision?)";
+                          "wgpu::VertexFormat::Float16 (potential loss of precision?)"
+                       << utils::io::endl;
            return VertexFormat ::Float16;
        case ElementType::USHORT:
            if (integer) return VertexFormat::Uint16;
            FWGPU_LOGW << "Requested Filament vertex format USHORT (float) and getting "
-                          "wgpu::VertexFormat::Float16 (potential loss of precision?)";
+                          "wgpu::VertexFormat::Float16 (potential loss of precision?)"
+                       << utils::io::endl;
            return VertexFormat::Float16;
        case ElementType::HALF:    return VertexFormat::Float16;
        case ElementType::INT:     return VertexFormat::Sint32;
@@ -118,49 +127,58 @@ namespace {
            if (integer) return VertexFormat::Sint8x2;
            FWGPU_LOGW
                    << "Requested Filament vertex format BYTE2 (float) but getting "
-                       "wgpu::VertexFormat::Float16x2 (no direct mapping in wgpu for 8 bit float)";
+                       "wgpu::VertexFormat::Float16x2 (no direct mapping in wgpu for 8 bit float)"
+                    << utils::io::endl;
            return VertexFormat::Float16x2;
        case ElementType::UBYTE2:
            if (integer) return VertexFormat::Uint8x2;
            FWGPU_LOGW
                    << "Requested Filament vertex format UBYTE2 (float) but getting "
-                       "wgpu::VertexFormat::Float16x2 (no direct mapping in wgpu for 8 bit float)";
+                       "wgpu::VertexFormat::Float16x2 (no direct mapping in wgpu for 8 bit float)"
+                    << utils::io::endl;
            return VertexFormat::Float16x2;
        case ElementType::SHORT2:
            if (integer) return VertexFormat::Sint16x2;
            FWGPU_LOGW << "Requested Filament vertex format SHORT2 (float) but getting "
-                          "wgpu::VertexFormat::Float16x2 (potential loss of precision?)";
+                          "wgpu::VertexFormat::Float16x2 (potential loss of precision?)"
+                       << utils::io::endl;
            return VertexFormat::Float16x2;
        case ElementType::USHORT2:
            if (integer) return VertexFormat::Uint16x2;
            FWGPU_LOGW << "Requested Filament vertex format USHORT2 (float) but getting "
-                          "wgpu::VertexFormat::Float16x2 (potential loss of precision?)";
+                          "wgpu::VertexFormat::Float16x2 (potential loss of precision?)"
+                       << utils::io::endl;
            return VertexFormat::Float16x2;
        case ElementType::HALF2:   return VertexFormat::Float16x2;
        case ElementType::FLOAT2:  return VertexFormat::Float32x2;
        // Three Component Types
        case ElementType::BYTE3:
            FWGPU_LOGW << "Requested Filament vertex format BYTE3 but getting "
-                          "wgpu::VertexFormat::Sint8x4 (no direct mapping in wgpu for x3 byte)";
+                          "wgpu::VertexFormat::Sint8x4 (no direct mapping in wgpu for x3 byte)"
+                       << utils::io::endl;
            return VertexFormat::Sint8x4; // NOT MINSPEC
        case ElementType::UBYTE3:
            FWGPU_LOGW << "Requested Filament vertex format UBYTE3 but getting "
-                          "wgpu::VertexFormat::Uint8x4 (no direct mapping in wgpu for x3 byte)";
+                          "wgpu::VertexFormat::Uint8x4 (no direct mapping in wgpu for x3 byte)"
+                       << utils::io::endl;
            return VertexFormat::Uint8x4; // NOT MINSPEC
        case ElementType::SHORT3:
            FWGPU_LOGW
                    << "Requested Filament vertex format SHORT3 but getting "
-                       "wgpu::VertexFormat::Sint16x4 (no direct mapping in wgpu for x3 half/short)";
+                       "wgpu::VertexFormat::Sint16x4 (no direct mapping in wgpu for x3 half/short)"
+                    << utils::io::endl;
            return VertexFormat::Sint16x4; // NOT MINSPEC
        case ElementType::USHORT3:
            FWGPU_LOGW
                    << "Requested Filament vertex format USHORT3 but getting "
-                       "wgpu::VertexFormat::Uint16x4 (no direct mapping in wgpu for x3 half/short)";
+                       "wgpu::VertexFormat::Uint16x4 (no direct mapping in wgpu for x3 half/short)"
+                    << utils::io::endl;
            return VertexFormat::Uint16x4; // NOT MINSPEC
        case ElementType::HALF3:
            FWGPU_LOGW
                    << "Requested Filament vertex format HALF3 but getting "
-                       "wgpu::VertexFormat::Float16x4 (no direct mapping in wgpu for x3 half/short)";
+                       "wgpu::VertexFormat::Float16x4 (no direct mapping in wgpu for x3 half/short)"
+                    << utils::io::endl;
            return VertexFormat::Float16x4; // NOT MINSPEC
        case ElementType::FLOAT3:  return VertexFormat::Float32x3;
        // Four Component Types
@@ -168,23 +186,27 @@ namespace {
            if (integer) return VertexFormat::Sint8x4;
            FWGPU_LOGW
                    << "Requested Filament vertex format BYTE4 (float) but getting "
-                       "wgpu::VertexFormat::Float16x4 (no direct mapping in wgpu for 8 bit float)";
+                       "wgpu::VertexFormat::Float16x4 (no direct mapping in wgpu for 8 bit float)"
+                    << utils::io::endl;
            return VertexFormat::Float16x4;
        case ElementType::UBYTE4:
            if (integer) return VertexFormat::Uint8x4;
            FWGPU_LOGW
                    << "Requested Filament vertex format UBYTE4 (float) but getting "
-                       "wgpu::VertexFormat::Float16x4 (no direct mapping in wgpu for 8 bit float)";
+                       "wgpu::VertexFormat::Float16x4 (no direct mapping in wgpu for 8 bit float)"
+                    << utils::io::endl;
            return VertexFormat::Float16x4;
        case ElementType::SHORT4:
            if (integer) return VertexFormat::Sint16x4;
            FWGPU_LOGW << "Requested Filament vertex format SHORT4 (float) but getting "
-                          "wgpu::VertexFormat::Float16x4 (potential loss of precision?)";
+                          "wgpu::VertexFormat::Float16x4 (potential loss of precision?)"
+                       << utils::io::endl;
            return VertexFormat::Float16x4;
        case ElementType::USHORT4:
            if (integer) return VertexFormat::Uint16x4;
            FWGPU_LOGW << "Requested Filament vertex format USHORT4 (float) but getting "
-                          "wgpu::VertexFormat::Float16x4 (potential loss of precision?)";
+                          "wgpu::VertexFormat::Float16x4 (potential loss of precision?)"
+                       << utils::io::endl;
            return VertexFormat::Float16x4;
        case ElementType::HALF4:   return VertexFormat::Float16x4;
        case ElementType::FLOAT4:  return VertexFormat::Float32x4;
@@ -24,6 +24,7 @@
 #include <backend/Platform.h>
 #include <utils/Hash.h>
 #include <utils/Panic.h>
+#include <utils/ostream.h>

 #include <dawn/webgpu_cpp_print.h>
 #include <webgpu/webgpu_cpp.h>
@@ -38,7 +39,6 @@
 #include <utility>
 #include <vector>
 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
-#include <string>
 #include <string_view>
 #include <variant>
 #endif
@@ -53,11 +53,10 @@ namespace filament::backend {

 namespace {

-// The SPD Algorithm can make use of up to 12 storage texture attachments
-constexpr uint32_t MAX_MIPMAP_STORAGE_TEXTURES_PER_STAGE = 12u;
-
-constexpr std::array REQUIRED_FEATURES = {
-    wgpu::FeatureName::TransientAttachments,
+constexpr std::array REQUIRED_FEATURES = { wgpu::FeatureName::TransientAttachments,
+    /*To make filtering assumptions like we want while waiting for Filament to provide that info,
+       float 32 needs to be filterable*/
+    wgpu::FeatureName::Float32Filterable,
    // Qualcomm 500 and 600 GPUs do not support this so it is not part of core webgpu spec. To
    // support such devices, we will either need Filament to not attempt this, or find another
    // workaround. https://github.com/gpuweb/gpuweb/issues/2648
@@ -118,6 +117,28 @@ constexpr void forEachLimitToValidate(std::function<bool(LimitToValidate const)>
    }
 }

+#if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
+utils::io::ostream& operator<<(utils::io::ostream& out,
+        const wgpu::WGSLLanguageFeatureName languageFeatureName) noexcept {
+    return streamInsertWebGPUPrintable(out, languageFeatureName);
+}
+
+utils::io::ostream& operator<<(utils::io::ostream& out,
+        const wgpu::FeatureName featureName) noexcept {
+    return streamInsertWebGPUPrintable(out, featureName);
+}
+#endif
+
+template<typename STREAM_TYPE>
+STREAM_TYPE& operator<<(STREAM_TYPE& out, wgpu::RequestAdapterOptions const& options) noexcept {
+    return streamInsertRequestAdapterOptions(out, options);
+}
+
+template<class STREAM_TYPE>
+STREAM_TYPE& operator<<(STREAM_TYPE& out, wgpu::AdapterInfo const& info) noexcept {
+    return streamInsertRequestAdapterInfo(out, info);
+}
+
 constexpr bool isDefined(uint32_t limit) { return limit < wgpu::kLimitU32Undefined; }

 [[maybe_unused]] constexpr bool isDefined(uint64_t limit) {
@@ -238,7 +259,7 @@ void printInstanceDetails(wgpu::Instance const& instance) {
                    supportedWGSLLanguageFeatures.features +
                            supportedWGSLLanguageFeatures.featureCount,
                    [](wgpu::WGSLLanguageFeatureName const featureName) {
-                        FWGPU_LOGI << "  " << webGPUPrintableToString(featureName);
+                        FWGPU_LOGI << "  " << featureName;
                    });
        }
    }
@@ -278,22 +299,23 @@ void printInstanceDetails(wgpu::Instance const& instance) {

 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
 void printLimit(std::string_view name, const std::variant<uint32_t, uint64_t> value) {
-    static constexpr std::string_view indent = "  ";
+    FWGPU_LOGI << "  " << name.data() << ": ";
    bool undefined = true;
    if (std::holds_alternative<uint32_t>(value)) {
        if (std::get<uint32_t>(value) != WGPU_LIMIT_U32_UNDEFINED) {
            undefined = false;
-            FWGPU_LOGI << indent << name.data() << ": " << std::get<uint32_t>(value);
+            FWGPU_LOGI << std::get<uint32_t>(value);
        }
    } else if (std::holds_alternative<uint64_t>(value)) {
        if (std::get<uint64_t>(value) != WGPU_LIMIT_U64_UNDEFINED) {
            undefined = false;
-            FWGPU_LOGI << indent << name.data() << ": " << std::get<uint64_t>(value);
+            FWGPU_LOGI << std::get<uint64_t>(value);
        }
    }
    if (undefined) {
-        FWGPU_LOGI << indent << name.data() << ": UNDEFINED";
+        FWGPU_LOGI << "UNDEFINED";
    }
+    FWGPU_LOGI << "";
 }
 #endif// FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)

@@ -371,16 +393,16 @@ struct AdapterDetails final {
    }
 };

-[[nodiscard]] std::string toString(AdapterDetails const& details) {
-    std::stringstream out;
-    out << adapterInfoToString(details.info)
+template<class STREAM_TYPE>
+STREAM_TYPE& operator<<(STREAM_TYPE& out, AdapterDetails const& details) noexcept {
+    out << details.info
        << " power preference " << powerPreferenceToString(details.powerPreference);
-    return out.str();
+    return out;
 }

 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
 void printAdapterDetails(AdapterDetails const& details) {
-    FWGPU_LOGI << "Selected WebGPU adapter info: " << toString(details);
+    FWGPU_LOGI << "Selected WebGPU adapter info: " << details;
    wgpu::SupportedFeatures supportedFeatures{};
    details.adapter.GetFeatures(&supportedFeatures);
    FWGPU_LOGI << "WebGPU adapter supported features (" << supportedFeatures.featureCount
@@ -389,7 +411,7 @@ void printAdapterDetails(AdapterDetails const& details) {
        std::for_each(supportedFeatures.features,
                supportedFeatures.features + supportedFeatures.featureCount,
                [](wgpu::FeatureName const featureName) {
-                    FWGPU_LOGI << "  " << webGPUPrintableToString(featureName);
+                    FWGPU_LOGI << "  " << featureName;
                });
    }
    wgpu::Limits supportedLimits{};
@@ -422,12 +444,12 @@ struct AdapterDetailsHash final {
                    return details.adapter.HasFeature(featureName);
                })) {
 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
-        FWGPU_LOGI << "WebGPU adapter " << toString(details)
+        FWGPU_LOGI << "WebGPU adapter " << details
                   << " does not have the minimum required features.";
        FWGPU_LOGI << "Missing required feature(s): ";
        for (wgpu::FeatureName const& requiredFeature: REQUIRED_FEATURES) {
            if (!details.adapter.HasFeature(requiredFeature)) {
-                FWGPU_LOGI << webGPUPrintableToString(requiredFeature);
+                FWGPU_LOGI << requiredFeature;
            }
        }
        FWGPU_LOGI << "";
@@ -436,10 +458,10 @@ struct AdapterDetailsHash final {
    }
    wgpu::Limits supportedLimits {};
    FILAMENT_CHECK_POSTCONDITION(details.adapter.GetLimits(&supportedLimits))
-            << "Failed to get limits for WebGPU adapter: " << toString(details);
+            << "Failed to get limits for WebGPU adapter: " << details;
    if (!satisfiesLimits(supportedLimits)) {
 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
-        FWGPU_LOGI << " (for WebGPU adapter " << toString(details) << ")";
+        FWGPU_LOGI << " (for WebGPU adapter " << details << ")";
 #endif
        return false;
    }
@@ -465,15 +487,14 @@ struct AdapterDetailsHash final {
                            status != wgpu::RequestAdapterStatus::CallbackCancelled)
                            << "Failed to request a WebGPU adapter due to the request callback "
                               "being cancelled? Options: "
-                            << adapterOptionsToString(options) << " " << message.data;
+                            << options << " " << message.data;
                    FILAMENT_CHECK_POSTCONDITION(status != wgpu::RequestAdapterStatus::Error)
                            << "Failed to request a WebGPU adapter due to an error. Options: "
-                            << adapterOptionsToString(options) << " Error: " << message.data;
+                            << options << " Error: " << message.data;
                    if (status == wgpu::RequestAdapterStatus::Success) {
                        AdapterDetails details = AdapterDetails(readyAdapter);
                        FILAMENT_CHECK_POSTCONDITION(readyAdapter.GetInfo(&details.info))
-                                << "Failed to get info for adapter (options: "
-                                << adapterOptionsToString(options) << ")";
+                                << "Failed to get info for adapter (options: " << options << ")";
                        const std::lock_guard<std::mutex> lock(adaptersMutex);
                        compatibleAdapters.emplace(std::move(details.info), details.powerPreference,
                                std::move(details.adapter));
@@ -488,11 +509,9 @@ struct AdapterDetailsHash final {
        wgpu::Future& future = futures[i];
        wgpu::WaitStatus status = instance.WaitAny(future, REQUEST_ADAPTER_TIMEOUT_NANOSECONDS);
        FILAMENT_CHECK_POSTCONDITION(status != wgpu::WaitStatus::TimedOut)
-                << "Timed out requesting a WebGPU adapter with options "
-                << adapterOptionsToString(options);
+                << "Timed out requesting a WebGPU adapter with options " << options;
        FILAMENT_CHECK_POSTCONDITION(status != wgpu::WaitStatus::Error)
-                << "Failed to request a WebGPU adapter with options "
-                << adapterOptionsToString(options)
+                << "Failed to request a WebGPU adapter with options " << options
                << " due to an error (as request was made synchronous)";
        assert_invariant(status == wgpu::WaitStatus::Success);
    }
@@ -500,7 +519,7 @@ struct AdapterDetailsHash final {
 #if FWGPU_ENABLED(FWGPU_PRINT_SYSTEM)
    FWGPU_LOGI << compatibleAdapters.size() << " WebGPU adapter(s) found:";
    for (auto& details: compatibleAdapters) {
-        FWGPU_LOGI << "  WebGPU adapter: " << toString(details);
+        FWGPU_LOGI << "  WebGPU adapter: " << details;
    }
 #endif
    return compatibleAdapters;
@@ -567,7 +586,7 @@ void printDeviceDetails(wgpu::Device const& device) {
        std::for_each(supportedFeatures.features,
                supportedFeatures.features + supportedFeatures.featureCount,
                [](wgpu::FeatureName const featureName) {
-                    FWGPU_LOGI << "  " << webGPUPrintableToString(featureName);
+                    FWGPU_LOGI << "  " << featureName;
                });
    }
    wgpu::Limits supportedLimits{};
@@ -609,21 +628,7 @@ wgpu::Device WebGPUPlatform::requestDevice(wgpu::Adapter const& adapter) {
    deviceDescriptor.defaultQueue.label = "default_queue";
    deviceDescriptor.requiredFeatureCount = enabledFeatures.size();
    deviceDescriptor.requiredFeatures = enabledFeatures.data();
-
-    // It is helpful to increase maxStorageTexturesPerShaderStage if the hardware supports it, but
-    // not required. This allows our mipmap generation to perform as well as possible for the given
-    // hardware. If we have more cases of "Nice to increase" limits like this we can generalize it
-    // in the future.
-    wgpu::Limits supportedLimits{};
-    FILAMENT_CHECK_POSTCONDITION(
-            adapter.GetLimits(&supportedLimits).status == wgpu::Status::Success)
-            << "Failed to get limits for WebGPU adapter";
-    auto limitsToRequest = REQUIRED_LIMITS;
-    limitsToRequest.maxStorageTexturesPerShaderStage =
-            std::min(MAX_MIPMAP_STORAGE_TEXTURES_PER_STAGE,
-                    supportedLimits.maxStorageTexturesPerShaderStage);
-    deviceDescriptor.requiredLimits = &limitsToRequest;
-
+    deviceDescriptor.requiredLimits = &REQUIRED_LIMITS;
    deviceDescriptor.SetDeviceLostCallback(wgpu::CallbackMode::AllowSpontaneous,
            [](wgpu::Device const&, wgpu::DeviceLostReason const& reason,
                    wgpu::StringView message) {
@@ -679,6 +684,7 @@ wgpu::Device WebGPUPlatform::requestDevice(wgpu::Adapter const& adapter) {
                            "adapter should support them: %s\n",
                missingFeatures, featureNamesStream.str().data());
    }
+    wgpu::Limits supportedLimits {};
    FILAMENT_CHECK_POSTCONDITION(device.GetLimits(&supportedLimits))
            << "Failed to get limits for the device?";
    FILAMENT_CHECK_POSTCONDITION(satisfiesLimits(supportedLimits))
@@ -40,24 +40,18 @@ using namespace filament::math;

 using namespace image;
 #endif
-#include <iostream>

 namespace test {

 Backend BackendTest::sBackend = Backend::NOOP;
 OperatingSystem BackendTest::sOperatingSystem = OperatingSystem::OTHER;
 bool BackendTest::sIsMobilePlatform = false;
-int BackendTest::sArgc = 0;
-char** BackendTest::sArgv = nullptr;
 std::vector<std::string> BackendTest::sFailedImages;

-void BackendTest::init(Backend backend, OperatingSystem operatingSystem, bool isMobilePlatform,
-        int argc, char** argv) {
+void BackendTest::init(Backend backend, OperatingSystem operatingSystem, bool isMobilePlatform) {
    sBackend = backend;
    sOperatingSystem = operatingSystem;
    sIsMobilePlatform = isMobilePlatform;
-    sArgc = argc;
-    sArgv = argv;
 }

 BackendTest::BackendTest() : commandBufferQueue(CONFIG_MIN_COMMAND_BUFFERS_SIZE,
@@ -166,11 +160,6 @@ void BackendTest::markImageAsFailure(std::string failedImageName) {
    sFailedImages.emplace_back(std::move(failedImageName));
 }

-std::filesystem::path BackendTest::binaryDirectory() {
-    assert(sArgc >= 1);
-    return std::filesystem::path(sArgv[0]).remove_filename().string();
-}
-
 void BackendTest::recordFailedImages() {
    if (!sFailedImages.empty()) {
        std::string failedImages;
@@ -198,9 +187,8 @@ public:
    }
 };

-void initTests(Backend backend, OperatingSystem operatingSystem, bool isMobile, int& argc,
-        char* argv[]) {
-    BackendTest::init(backend, operatingSystem, isMobile, argc, argv);
+void initTests(Backend backend, OperatingSystem operatingSystem, bool isMobile, int& argc, char* argv[]) {
+    BackendTest::init(backend, operatingSystem, isMobile);
    ::testing::InitGoogleTest(&argc, argv);
    ::testing::AddGlobalTestEnvironment(new Environment);
 }
@@ -19,8 +19,6 @@

 #include <gtest/gtest.h>

-#include <filesystem>
-
 #include <backend/Platform.h>

 #include "private/backend/CommandBufferQueue.h"
@@ -33,20 +31,16 @@ namespace test {

 class BackendTest : public ::testing::Test {
 public:
-    static void init(Backend backend, OperatingSystem operatingSystem, bool isMobilePlatform,
-            int argc, char** argv);
+
+    static void init(Backend backend, OperatingSystem operatingSystem, bool isMobilePlatform);

    static Backend sBackend;
    static OperatingSystem sOperatingSystem;
    static bool sIsMobilePlatform;
-    static int sArgc;
-    static char** sArgv;

    // Takes the name of the image that wasn't correct, without the .png suffix
    static void markImageAsFailure(std::string failedImageName);

-    static std::filesystem::path binaryDirectory();
-
 protected:

    BackendTest();
@@ -59,28 +59,28 @@ uint32_t ScreenshotParams::expectedHash() const {
    return mExpectedPixelHash;
 }

-std::filesystem::path ScreenshotParams::actualDirectoryPath() {
-    return BackendTest::binaryDirectory().append("images/actual_images");
+std::string ScreenshotParams::actualDirectoryPath() {
+    return "images/actual_images";
 }

 std::string ScreenshotParams::actualFileName() const {
    return absl::StrFormat("%s_actual.png", mFileName);
 }

-std::filesystem::path ScreenshotParams::actualFilePath() const {
-    return actualDirectoryPath().append(actualFileName());
+std::string ScreenshotParams::actualFilePath() const {
+    return absl::StrFormat("%s/%s", actualDirectoryPath(), actualFileName());
 }

-std::filesystem::path ScreenshotParams::expectedDirectoryPath() {
-    return BackendTest::binaryDirectory().append("images/expected_images");
+std::string ScreenshotParams::expectedDirectoryPath() {
+    return "images/expected_images";
 }

 std::string ScreenshotParams::expectedFileName() const {
    return absl::StrFormat("%s.png", mFileName);
 }

-std::filesystem::path ScreenshotParams::expectedFilePath() const {
-    return expectedDirectoryPath().append(expectedFileName());
+std::string ScreenshotParams::expectedFilePath() const {
+    return absl::StrFormat("%s/%s", expectedDirectoryPath(), expectedFileName());
 }

 const std::string ScreenshotParams::filePrefix() const {
@@ -17,7 +17,6 @@
 #ifndef TNT_IMAGE_EXPECTATIONS_H
 #define TNT_IMAGE_EXPECTATIONS_H

-#include <filesystem>
 #include <vector>

 #include "gtest/gtest.h"
@@ -52,12 +51,12 @@ public:
    bool isSrgb() const;
    uint32_t expectedHash() const;

-    static std::filesystem::path actualDirectoryPath();
+    static std::string actualDirectoryPath();
    std::string actualFileName() const;
-    std::filesystem::path actualFilePath() const;
-    static std::filesystem::path expectedDirectoryPath();
+    std::string actualFilePath() const;
+    static std::string expectedDirectoryPath();
    std::string expectedFileName() const;
-    std::filesystem::path expectedFilePath() const;
+    std::string expectedFilePath() const;
    const std::string filePrefix() const;

 private:
@@ -139,24 +139,6 @@ TEST_F(ReadPixelsTest, ReadPixels) {
            return bufferDimension;
        }

-        void exportScreenshot(void* pixelData) const {
-#ifndef FILAMENT_IOS
-            const size_t width = readRect.width, height = readRect.height;
-            LinearImage image(width, height, 4);
-            if (format == PixelDataFormat::RGBA && type == PixelDataType::UBYTE) {
-                image = toLinearWithAlpha<uint8_t>(width, height, width * 4, (uint8_t*)pixelData);
-            }
-            if (format == PixelDataFormat::RGBA && type == PixelDataType::FLOAT) {
-                memcpy(image.getPixelRef(), pixelData, width * height * sizeof(math::float4));
-            }
-            std::string png = std::string(testName) + ".png";
-            std::filesystem::path path = ScreenshotParams::actualDirectoryPath();
-            path.append(png);
-            std::ofstream outputStream(path.c_str(), std::ios::binary | std::ios::trunc);
-            ImageEncoder::encode(outputStream, ImageEncoder::Format::PNG, image, "", png);
-#endif
-        }
-
        // The format and type for the readPixels call.
        PixelDataFormat format = PixelDataFormat::RGBA;
        PixelDataType type = PixelDataType::UBYTE;
@@ -329,8 +311,6 @@ TEST_F(ReadPixelsTest, ReadPixels) {
                    const auto* test = (const TestCase*)user;
                    assert_invariant(test);

-                    test->exportScreenshot(buffer);
-
                    // Hash the contents of the buffer and check that they match.
                    uint32_t hash = utils::hash::murmur3((const uint32_t*)buffer, size / 4, 0);

@@ -190,7 +190,6 @@ public:
    using FeatureLevel = backend::FeatureLevel;
    using StereoscopicType = backend::StereoscopicType;
    using Driver = backend::Driver;
-    using GpuContextPriority = backend::Platform::GpuContextPriority;

    /**
     * Config is used to define the memory footprint used by the engine, such as the
@@ -318,15 +317,6 @@ public:
         */
        size_t metalUploadBufferSizeBytes = 512 * 1024;

-        /**
-         * The action to take if a Drawable cannot be acquired.
-         *
-         * Each frame rendered requires a CAMetalDrawable texture, which is
-         * presented on-screen at the completion of each frame. These are
-         * limited and provided round-robin style by the system.
-         */
-        bool metalDisablePanicOnDrawableFailure = false;
-
        /**
         * Set to `true` to forcibly disable parallel shader compilation in the backend.
         * Currently only honored by the GL and Metal backends.
@@ -411,11 +401,6 @@ public:
         * @deprecated use "backend.opengl.assert_native_window_is_valid" feature flag instead
         */
        bool assertNativeWindowIsValid = false;
-
-        /**
-         * GPU context priority level. Controls GPU work scheduling and preemption.
-         */
-        GpuContextPriority gpuContextPriority = GpuContextPriority::DEFAULT;
    };


@@ -57,8 +57,7 @@ class UTILS_PUBLIC MaterialInstance : public FilamentAPI {

 public:
    using CullingMode = backend::CullingMode;
-    // ReSharper disable once CppRedundantQualifier
-    using TransparencyMode = filament::TransparencyMode;
+    using TransparencyMode = TransparencyMode;
    using DepthFunc = backend::SamplerCompareFunc;
    using StencilCompareFunc = backend::SamplerCompareFunc;
    using StencilOperation = backend::StencilOperation;
@@ -87,6 +86,9 @@ public:
            std::is_same_v<math::mat3f, T>
    >;

+    template<typename T>
+    using is_supported_constant_parameter_t = std::enable_if_t<std::is_same_v<bool, T>>;
+
    /**
     * Creates a new MaterialInstance using another MaterialInstance as a template for initialization.
     * The new MaterialInstance is an instance of the same Material of the template instance and
@@ -238,13 +240,13 @@ public:

    /**
     * Gets the value of a parameter by name.
-     * 
+     *
     * Note: Only supports non-texture parameters such as numeric and math types.
-     * 
+     *
     * @param name          Name of the parameter as defined by Material. Cannot be nullptr.
     * @param nameLength    Length in `char` of the name parameter.
     * @throws utils::PreConditionPanic if name doesn't exist or no-op if exceptions are disabled.
-     * 
+     *
     * @see Material::hasParameter
     */
    template<typename T>
@@ -262,6 +264,53 @@ public:
        return getParameter<T>(name, strlen(name));
    }

+    /**
+     * Set a mutable constant parameter by name.
+     *
+     * @param name          Name of the parameter as defined by Material. Cannot be nullptr.
+     * @param nameLength    Length in `char` of the name parameter.
+     * @param value         Value of the parameter to set.
+     * @throws utils::PreConditionPanic if name doesn't exist or no-op if exceptions are disabled.
+     */
+    template<typename T, typename = is_supported_constant_parameter_t<T>>
+    void setConstant(const char* UTILS_NONNULL name, size_t nameLength, T const& value);
+
+    /** inline helper to provide the name as a null-terminated string literal */
+    template<typename T, typename = is_supported_constant_parameter_t<T>>
+    void setConstant(StringLiteral const name, T const& value) {
+        setConstant<T>(name.data, name.size, value);
+    }
+
+    /** inline helper to provide the name as a null-terminated C string */
+    template<typename T, typename = is_supported_constant_parameter_t<T>>
+    void setConstant(const char* UTILS_NONNULL name, T const& value) {
+        setConstant<T>(name, strlen(name), value);
+    }
+
+    /**
+     * Gets the value of a mutable constant parameter by name.
+     *
+     * @param name          Name of the parameter as defined by Material. Cannot be nullptr.
+     * @param nameLength    Length in `char` of the name parameter.
+     * @throws utils::PreConditionPanic if name doesn't exist or no-op if exceptions are disabled.
+     *
+     * @see Material::hasConstant
+     */
+    template<typename T, typename = is_supported_constant_parameter_t<T>>
+    T getConstant(const char* UTILS_NONNULL name, size_t nameLength) const;
+
+    /** inline helper to provide the name as a null-terminated C string */
+    template<typename T, typename = is_supported_constant_parameter_t<T>>
+    T getConstant(StringLiteral const name) const {
+        return getConstant<T>(name.data, name.size);
+    }
+
+    /** inline helper to provide the name as a null-terminated C string */
+    template<typename T, typename = is_supported_constant_parameter_t<T>>
+    T getConstant(const char* UTILS_NONNULL name) const {
+        return getConstant<T>(name, strlen(name));
+    }
+
    /**
     * Set-up a custom scissor rectangle; by default it is disabled.
     *
@@ -232,6 +232,46 @@ template UTILS_PUBLIC mat3f MaterialInstance::getParameter<mat3f>      (const ch

 // ------------------------------------------------------------------------------------------------

+template<>
+inline void FMaterialInstance::setConstantImpl<bool>(std::string_view const name, bool const& value) {
+    std::optional<uint32_t> id = mMaterial->getMutableConstantId(name);
+    FILAMENT_CHECK_PRECONDITION(id.has_value()) << "No mutable constant with name " << name;
+    mConstants.set(*id, value);
+}
+
+template<typename T, typename>
+void MaterialInstance::setConstant(const char* name, size_t nameLength, T const& value) {
+    downcast(this)->setConstantImpl({ name, nameLength }, value);
+}
+
+// Explicit template instantiation of our supported types.
+//
+// Mutable spec constants will probably only ever allow bools, but it's nice to keep the API
+// forwards-compatible.
+template UTILS_PUBLIC void MaterialInstance::setConstant<bool>(const char* name, size_t nameLength, bool const& v);
+
+// ------------------------------------------------------------------------------------------------
+
+template<>
+inline bool FMaterialInstance::getConstantImpl<bool>(std::string_view const name) const {
+    std::optional<uint32_t> id = mMaterial->getMutableConstantId(name);
+    FILAMENT_CHECK_PRECONDITION(id.has_value()) << "No mutable constant with name " << name;
+    return mConstants[*id];
+}
+
+template<typename T, typename>
+T MaterialInstance::getConstant(const char* name, size_t nameLength) const {
+    return downcast(this)->getConstantImpl<T>({ name, nameLength });
+}
+
+// Explicit template instantiation of our supported types.
+//
+// Mutable spec constants will probably only ever allow bools, but it's nice to keep the API
+// forwards-compatible.
+template UTILS_PUBLIC bool MaterialInstance::getConstant<bool>(const char* name, size_t nameLength) const;
+
+// ------------------------------------------------------------------------------------------------
+
 Material const* MaterialInstance::getMaterial() const noexcept {
    return downcast(this)->getMaterial();
 }
@@ -229,6 +229,11 @@ bool MaterialParser::getConstants(FixedCapacityVector<MaterialConstant>* contain
    return get<ChunkMaterialConstants>(container);
 }

+bool MaterialParser::getMutableConstants(
+        FixedCapacityVector<MaterialMutableConstant>* container) const noexcept {
+    return get<ChunkMaterialMutableConstants>(container);
+}
+
 bool MaterialParser::getPushConstants(CString* structVarName,
        FixedCapacityVector<MaterialPushConstant>* value) const noexcept {
    auto [start, end] = mImpl.mChunkContainer.getChunkRange(MaterialPushConstants);
@@ -481,7 +486,6 @@ bool ChunkSamplerInterfaceBlock::unflatten(Unflattener& unflattener,
        uint8_t fieldType = 0;
        uint8_t fieldFormat = 0;
        uint8_t fieldPrecision = 0;
-        bool fieldUnfilterable = false;
        bool fieldMultisample = false;

        if (!unflattener.read(&fieldName)) {
@@ -504,10 +508,6 @@ bool ChunkSamplerInterfaceBlock::unflatten(Unflattener& unflattener,
            return false;
        }

-        if (!unflattener.read(&fieldUnfilterable)) {
-            return false;
-        }
-
        if (!unflattener.read(&fieldMultisample)) {
            return false;
        }
@@ -517,7 +517,6 @@ bool ChunkSamplerInterfaceBlock::unflatten(Unflattener& unflattener,
                SamplerInterfaceBlock::Type(fieldType),
                SamplerInterfaceBlock::Format(fieldFormat),
                SamplerInterfaceBlock::Precision(fieldPrecision),
-                fieldUnfilterable,
                fieldMultisample);
    }

@@ -757,6 +756,38 @@ bool ChunkMaterialConstants::unflatten(Unflattener& unflattener,
    return true;
 }

+bool ChunkMaterialMutableConstants::unflatten(Unflattener& unflattener,
+        FixedCapacityVector<MaterialMutableConstant>* materialConstants) {
+    assert_invariant(materialConstants);
+
+    // Read number of constants.
+    uint64_t numConstants = 0;
+    if (!unflattener.read(&numConstants)) {
+        return false;
+    }
+
+    materialConstants->reserve(numConstants);
+    materialConstants->resize(numConstants);
+
+    for (uint64_t i = 0; i < numConstants; i++) {
+        CString constantName;
+        bool defaultValue;
+
+        if (!unflattener.read(&constantName)) {
+            return false;
+        }
+
+        if (!unflattener.read(&defaultValue)) {
+            return false;
+        }
+
+        (*materialConstants)[i].name = std::move(constantName);
+        (*materialConstants)[i].defaultValue = defaultValue;
+    }
+
+    return true;
+}
+
 bool ChunkMaterialPushConstants::unflatten(Unflattener& unflattener,
        CString* structVarName,
        FixedCapacityVector<MaterialPushConstant>* materialPushConstants) {
@@ -49,6 +49,7 @@ class BufferInterfaceBlock;
 class SamplerInterfaceBlock;
 struct SubpassInfo;
 struct MaterialConstant;
+struct MaterialMutableConstant;
 struct MaterialPushConstant;

 class MaterialParser {
@@ -79,6 +80,8 @@ public:
    bool getShaderModels(uint32_t* value) const noexcept;
    bool getMaterialProperties(uint64_t* value) const noexcept;
    bool getConstants(utils::FixedCapacityVector<MaterialConstant>* value) const noexcept;
+    bool getMutableConstants(utils::FixedCapacityVector<MaterialMutableConstant>* value)
+        const noexcept;
    bool getPushConstants(utils::CString* structVarName,
            utils::FixedCapacityVector<MaterialPushConstant>* value) const noexcept;

@@ -237,6 +240,13 @@ struct ChunkMaterialConstants {
    static filamat::ChunkType const tag = filamat::MaterialConstants;
 };

+struct ChunkMaterialMutableConstants {
+    static bool unflatten(filaflat::Unflattener& unflattener,
+            utils::FixedCapacityVector<MaterialMutableConstant>* materialConstants);
+    using Container = utils::FixedCapacityVector<MaterialMutableConstant>;
+    static filamat::ChunkType const tag = filamat::MaterialMutableConstants;
+};
+
 struct ChunkMaterialPushConstants {
    static bool unflatten(filaflat::Unflattener& unflattener, utils::CString* structVarName,
            utils::FixedCapacityVector<MaterialPushConstant>* materialPushConstants);
@@ -187,7 +187,10 @@ FMaterial* PostProcessManager::PostProcessMaterial::getMaterial(FEngine& engine,
    if (UTILS_UNLIKELY(mSize)) {
        loadMaterial(engine);
    }
-    mMaterial->prepareProgram(Variant{ Variant::type_t(variant) });
+    mMaterial->prepareProgram(Variant{ Variant::type_t(variant) },
+            // TODO(exv): allow post process materials to use mutable spec constants?
+            Program::MutableSpecConstantsInfo(0)
+            );
    return mMaterial;
 }

@@ -423,7 +426,10 @@ UTILS_NOINLINE
 PipelineState PostProcessManager::getPipelineState(
        FMaterial const* const ma, PostProcessVariant variant) const noexcept {
    return {
-            .program = ma->getProgram(Variant{ Variant::type_t(variant) }),
+            .program = ma->getProgram(Variant{ Variant::type_t(variant) },
+                    // TODO(exv): allow post process materials to use mutable spec constants?
+                    Program::MutableSpecConstantsInfo(0)
+                    ),
            .vertexBufferInfo = mFullScreenQuadVbih,
            .pipelineLayout = {
                    .setLayout = {
@@ -2989,7 +2995,7 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::upscale(FrameGraph& fg, bool
    }

    if (dsrOptions.quality == QualityLevel::LOW) {
-        return upscaleBilinear(fg, dsrOptions, input, vp, outDesc, filter);
+        return upscaleBilinear(fg, translucent, dsrOptions, input, vp, outDesc, filter);
    }
    if (dsrOptions.quality == QualityLevel::MEDIUM) {
        return upscaleSGSR1(fg, sourceHasLuminance, dsrOptions, input, vp, outDesc);
@@ -2997,7 +3003,7 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::upscale(FrameGraph& fg, bool
    return upscaleFSR1(fg, dsrOptions, input, vp, outDesc);
 }

-FrameGraphId<FrameGraphTexture> PostProcessManager::upscaleBilinear(FrameGraph& fg,
+FrameGraphId<FrameGraphTexture> PostProcessManager::upscaleBilinear(FrameGraph& fg, bool translucent,
        DynamicResolutionOptions dsrOptions, FrameGraphId<FrameGraphTexture> const input,
        filament::Viewport const& vp, FrameGraphTexture::Descriptor const& outDesc,
        SamplerMagFilter filter) noexcept {
@@ -3016,10 +3022,18 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::upscaleBilinear(FrameGraph&
                        .attachments = { .color = { data.output } },
                        .clearFlags = TargetBufferFlags::DEPTH });
            },
-            [this, vp, filter](FrameGraphResources const& resources,
+            [this, vp, translucent, filter](FrameGraphResources const& resources,
                    auto const& data, DriverApi& driver) {
                bindPostProcessDescriptorSet(driver);

+                // helper to enable blending
+                auto enableTranslucentBlending = [](PipelineState& pipeline) {
+                    pipeline.rasterState.blendFunctionSrcRGB = BlendFunction::ONE;
+                    pipeline.rasterState.blendFunctionSrcAlpha = BlendFunction::ONE;
+                    pipeline.rasterState.blendFunctionDstRGB = BlendFunction::ONE_MINUS_SRC_ALPHA;
+                    pipeline.rasterState.blendFunctionDstAlpha = BlendFunction::ONE_MINUS_SRC_ALPHA;
+                };
+
                auto color = resources.getTexture(data.input);
                auto const& inputDesc = resources.getDescriptor(data.input);

@@ -3047,6 +3061,9 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::upscaleBilinear(FrameGraph&
                auto out = resources.getRenderPassInfo();

                auto pipeline = getPipelineState(material.getMaterial(mEngine));
+                if (translucent) {
+                    enableTranslucentBlending(pipeline);
+                }
                renderFullScreenQuad(out, pipeline, driver);
            });

@@ -3054,8 +3071,7 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::upscaleBilinear(FrameGraph&

    // if we had to take the low quality fallback, we still do the "sharpen pass"
    if (dsrOptions.sharpness > 0.0f) {
-        output = rcas(fg, dsrOptions.sharpness, output, outDesc,
-                false /* translucent=false, because dst buffer is allocated */);
+        output = rcas(fg, dsrOptions.sharpness, output, outDesc, translucent);
    }

    // we rely on automatic culling of unused render passes
@@ -3433,6 +3449,9 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::resolve(FrameGraph& fg,
        return input;
    }

+    // we currently don't support stencil resolve
+    assert_invariant(!isStencilFormat(inDesc.format));
+
    // The Metal / Vulkan backends currently don't support depth/stencil resolve.
    if (isDepthFormat(inDesc.format) && (!mEngine.getDriverApi().isDepthStencilResolveSupported())) {
        return resolveDepth(fg, outputBufferName, input, outDesc);
@@ -3450,9 +3469,6 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::resolve(FrameGraph& fg,

    auto const& ppResolve = fg.addPass<ResolveData>("resolve",
            [&](FrameGraph::Builder& builder, auto& data) {
-                // we currently don't support stencil resolve.
-                assert_invariant(!isStencilFormat(inDesc.format));
-
                data.input = builder.read(input, FrameGraphTexture::Usage::BLIT_SRC);
                data.output = builder.createTexture(outputBufferName, outDesc);
                data.output = builder.write(data.output, FrameGraphTexture::Usage::BLIT_DST);
@@ -3504,9 +3520,6 @@ FrameGraphId<FrameGraphTexture> PostProcessManager::resolveDepth(FrameGraph& fg,

    auto const& ppResolve = fg.addPass<ResolveData>("resolveDepth",
            [&](FrameGraph::Builder& builder, auto& data) {
-                // we currently don't support stencil resolve
-                assert_invariant(!isStencilFormat(inDesc.format));
-
                data.input = builder.sample(input);
                data.output = builder.createTexture(outputBufferName, outDesc);
                data.output = builder.write(data.output, FrameGraphTexture::Usage::DEPTH_ATTACHMENT);
@@ -257,7 +257,7 @@ public:
            FrameGraphId<FrameGraphTexture> input, Viewport const& vp,
            FrameGraphTexture::Descriptor const& outDesc, backend::SamplerMagFilter filter) noexcept;

-    FrameGraphId<FrameGraphTexture> upscaleBilinear(FrameGraph& fg,
+    FrameGraphId<FrameGraphTexture> upscaleBilinear(FrameGraph& fg, bool translucent,
            DynamicResolutionOptions dsrOptions, FrameGraphId<FrameGraphTexture> input,
            Viewport const& vp, FrameGraphTexture::Descriptor const& outDesc,
            backend::SamplerMagFilter filter) noexcept;
@@ -82,6 +82,8 @@ RenderPassBuilder& RenderPassBuilder::customCommand(

 RenderPass RenderPassBuilder::build(FEngine const& engine, DriverApi& driver) const {
    assert_invariant(mRenderableSoa);
+    assert_invariant(mScissorViewport.width  <= std::numeric_limits<int32_t>::max());
+    assert_invariant(mScissorViewport.height <= std::numeric_limits<int32_t>::max());
    return RenderPass{ engine, driver, *this };
 }

@@ -105,7 +107,8 @@ void RenderPass::DescriptorSetHandleDeleter::operator()(
 RenderPass::RenderPass(FEngine const& engine, DriverApi& driver,
        RenderPassBuilder const& builder) noexcept
        : mRenderableSoa(*builder.mRenderableSoa),
-          mColorPassDescriptorSet(builder.mColorPassDescriptorSet) {
+          mColorPassDescriptorSet(builder.mColorPassDescriptorSet),
+          mScissorViewport(builder.mScissorViewport) {

    // compute the number of commands we need
    updateSummedPrimitiveCounts(
@@ -243,7 +246,8 @@ void RenderPass::appendCommands(FEngine const& engine,
    for (Command const* first = curr, *last = curr + commandCount ; first != last ; ++first) {
        if (UTILS_LIKELY((first->key & CUSTOM_MASK) == uint64_t(CustomCommand::PASS))) {
            auto ma = first->info.mi->getMaterial();
-            ma->prepareProgram(first->info.materialVariant);
+            ma->prepareProgram(first->info.materialVariant,
+                    first->info.mi->getMutableSpecConstants());
        }
    }
 }
@@ -1095,7 +1099,8 @@ void RenderPass::Executor::execute(FEngine const& engine, DriverApi& driver,
                }

                assert_invariant(ma);
-                pipeline.program = ma->getProgram(info.materialVariant);
+                pipeline.program = ma->getProgram(info.materialVariant,
+                        info.mi->getMutableSpecConstants());

                if (UTILS_UNLIKELY(memcmp(&pipeline, &currentPipeline, sizeof(PipelineState)) != 0)) {
                    currentPipeline = pipeline;
@@ -306,12 +306,6 @@ public:
    // allocated commands ARE NOT freed, they're owned by the Arena
    ~RenderPass() noexcept;

-    // Specifies the viewport for the scissor rectangle, that is, the final scissor rect is
-    // offset by the viewport's left-top and clipped to the viewport's width/height.
-    void setScissorViewport(backend::Viewport const viewport) noexcept {
-        mScissorViewport = viewport;
-    }
-
    Command const* begin() const noexcept { return mCommandBegin; }
    Command const* end() const noexcept { return mCommandEnd; }
    bool empty() const noexcept { return begin() == end(); }
@@ -467,7 +461,7 @@ private:

    FScene::RenderableSoa const& mRenderableSoa;
    ColorPassDescriptorSet const* const mColorPassDescriptorSet;
-    backend::Viewport mScissorViewport{ 0, 0, INT32_MAX, INT32_MAX };
+    backend::Viewport const mScissorViewport{ 0, 0, INT32_MAX, INT32_MAX };
    Command const* /* const */ mCommandBegin = nullptr;   // Pointer to the first command
    Command const* /* const */ mCommandEnd = nullptr;     // Pointer to one past the last command
    mutable BufferObjectSharedHandle mInstancedUboHandle; // ubo for instanced primitives
@@ -482,6 +476,7 @@ class RenderPassBuilder {

    RenderPass::Arena& mArena;
    RenderPass::CommandTypeFlags mCommandTypeFlags{};
+    backend::Viewport mScissorViewport{ 0, 0, INT32_MAX, INT32_MAX };
    FScene::RenderableSoa const* mRenderableSoa = nullptr;
    utils::Range<uint32_t> mVisibleRenderables{};
    math::float3 mCameraPosition{};
@@ -512,6 +507,13 @@ public:
        return *this;
    }

+    // Specifies the viewport for the scissor rectangle, that is, the final scissor rect is
+    // offset by the viewport's left-top and clipped to the viewport's width/height.
+    RenderPassBuilder& scissorViewport(backend::Viewport const viewport) noexcept {
+        mScissorViewport = viewport;
+        return *this;
+    }
+
    // specifies the geometry to generate commands for
    RenderPassBuilder& geometry(
            FScene::RenderableSoa const& soa, utils::Range<uint32_t> const vr) noexcept {
@@ -40,6 +40,7 @@
 #include <utils/Panic.h>

 #include <algorithm>
+#include <optional>
 #include <utility>

 #include <stddef.h>
@@ -269,94 +270,87 @@ RendererUtils::ColorPassOutput RendererUtils::colorPass(
    };
 }

-
-RenderPass::Command const* RendererUtils::getFirstRefractionCommand(
-    RenderPass const& pass) noexcept {
-
-    // find the first refractive object in channel 2
-    RenderPass::Command const* const refraction = std::partition_point(pass.begin(), pass.end(),
-        [](auto const& command) {
-            constexpr uint64_t mask  = RenderPass::CHANNEL_MASK | RenderPass::PASS_MASK;
-            constexpr uint64_t channel = uint64_t(RenderableManager::Builder::DEFAULT_CHANNEL) << RenderPass::CHANNEL_SHIFT;
-            constexpr uint64_t value = channel | uint64_t(RenderPass::Pass::REFRACT);
-            return (command.key & mask) < value;
-        });
-
-    const bool hasScreenSpaceRefraction =
-            (refraction->key & RenderPass::PASS_MASK) == uint64_t(RenderPass::Pass::REFRACT);
-
-    return hasScreenSpaceRefraction ? refraction : nullptr;
-
-}
-
-RendererUtils::ColorPassOutput RendererUtils::refractionPass(
+std::optional<RendererUtils::ColorPassOutput> RendererUtils::refractionPass(
        FrameGraph& fg, FEngine& engine, FView const& view,
        ColorPassInput colorPassInput,
        ColorPassConfig config,
        PostProcessManager::ScreenSpaceRefConfig const& ssrConfig,
        PostProcessManager::ColorGradingConfig const colorGradingConfig,
-        RenderPass const& pass, RenderPass::Command const* const firstRefractionCommand) noexcept {
+        RenderPass const& pass) noexcept {

-    assert_invariant(firstRefractionCommand);
-    RenderPass::Command const* const refraction = firstRefractionCommand;
+    // find the first refractive object in channel 2
+    RenderPass::Command const* const refraction = std::partition_point(pass.begin(), pass.end(),
+            [](auto const& command) {
+                constexpr uint64_t mask  = RenderPass::CHANNEL_MASK | RenderPass::PASS_MASK;
+                constexpr uint64_t channel = uint64_t(RenderableManager::Builder::DEFAULT_CHANNEL) << RenderPass::CHANNEL_SHIFT;
+                constexpr uint64_t value = channel | uint64_t(RenderPass::Pass::REFRACT);
+                return (command.key & mask) < value;
+            });
+
+    const bool hasScreenSpaceRefraction =
+            (refraction->key & RenderPass::PASS_MASK) == uint64_t(RenderPass::Pass::REFRACT);

    // if there wasn't any refractive object, just skip everything below.
-    assert_invariant(!colorPassInput.linearColor);
-    assert_invariant(!colorPassInput.depth);
-    config.hasScreenSpaceReflectionsOrRefractions = true;
+    if (UTILS_UNLIKELY(hasScreenSpaceRefraction)) {
+        assert_invariant(!colorPassInput.linearColor);
+        assert_invariant(!colorPassInput.depth);
+        config.hasScreenSpaceReflectionsOrRefractions = true;

-    PostProcessManager& ppm = engine.getPostProcessManager();
-    auto const opaquePassOutput = colorPass(fg,
-            "Color Pass (opaque)", engine, view, colorPassInput, {
-                    // When rendering the opaques, we need to conserve the sample buffer,
-                    // so create a config that specifies the sample count.
-                    .width = config.physicalViewport.width,
-                    .height = config.physicalViewport.height,
-                    .samples = config.msaa,
-                    .format = config.hdrFormat
-            },
-            config, { .asSubpass = false, .customResolve = false },
-            pass.getExecutor(pass.begin(), refraction));
+        PostProcessManager& ppm = engine.getPostProcessManager();
+        auto const opaquePassOutput = colorPass(fg,
+                "Color Pass (opaque)", engine, view, colorPassInput, {
+                        // When rendering the opaques, we need to conserve the sample buffer,
+                        // so create a config that specifies the sample count.
+                        .width = config.physicalViewport.width,
+                        .height = config.physicalViewport.height,
+                        .samples = config.msaa,
+                        .format = config.hdrFormat
+                },
+                config, { .asSubpass = false, .customResolve = false },
+                pass.getExecutor(pass.begin(), refraction));


-    // Generate the mipmap chain
-    // Note: we can run some post-processing effects while the "color pass" descriptor set
-    // in bound because only the descriptor 0 (frame uniforms) matters, and it's
-    // present in both.
-    PostProcessManager::generateMipmapSSR(ppm, fg,
-            opaquePassOutput.linearColor,
-            ssrConfig.refraction,
-            true, ssrConfig);
+        // Generate the mipmap chain
+        // Note: we can run some post-processing effects while the "color pass" descriptor set
+        // in bound because only the descriptor 0 (frame uniforms) matters, and it's
+        // present in both.
+        PostProcessManager::generateMipmapSSR(ppm, fg,
+                opaquePassOutput.linearColor,
+                ssrConfig.refraction,
+                true, ssrConfig);

-    // Now we're doing the refraction pass proper.
-    // This uses the same framebuffer (color and depth) used by the opaque pass.
-    // For this reason, the `colorBufferDesc` parameter of colorPass() below is only used  for
-    // the width and height.
-    colorPassInput.linearColor = opaquePassOutput.linearColor;
-    colorPassInput.depth = opaquePassOutput.depth;
+        // Now we're doing the refraction pass proper.
+        // This uses the same framebuffer (color and depth) used by the opaque pass.
+        // For this reason, the `colorBufferDesc` parameter of colorPass() below is only used  for
+        // the width and height.
+        colorPassInput.linearColor = opaquePassOutput.linearColor;
+        colorPassInput.depth = opaquePassOutput.depth;

-    // Since we're reusing the existing target we don't want to clear any of its buffer.
-    // Important: if this target ended up being an imported target, then the clearFlags
-    // specified here wouldn't apply (the clearFlags of the imported target take precedence),
-    // and we'd end up clearing the opaque pass. This scenario never happens because it is
-    // prevented in Renderer.cpp's final blit.
-    config.clearFlags = TargetBufferFlags::NONE;
-    auto transparentPassOutput = colorPass(fg, "Color Pass (transparent)",
-            engine, view, colorPassInput, {
-                    .width = config.physicalViewport.width,
-                    .height = config.physicalViewport.height },
-            config, colorGradingConfig,
-            pass.getExecutor(refraction, pass.end()));
+        // Since we're reusing the existing target we don't want to clear any of its buffer.
+        // Important: if this target ended up being an imported target, then the clearFlags
+        // specified here wouldn't apply (the clearFlags of the imported target take precedence),
+        // and we'd end up clearing the opaque pass. This scenario never happens because it is
+        // prevented in Renderer.cpp's final blit.
+        config.clearFlags = TargetBufferFlags::NONE;
+        auto transparentPassOutput = colorPass(fg, "Color Pass (transparent)",
+                engine, view, colorPassInput, {
+                        .width = config.physicalViewport.width,
+                        .height = config.physicalViewport.height },
+                config, colorGradingConfig,
+                pass.getExecutor(refraction, pass.end()));

-    if (config.msaa > 1 && !colorGradingConfig.asSubpass) {
-        // We need to do a resolve here because later passes (such as color grading or DoF) will
-        // need to sample from 'output'. However, because we have MSAA, we know we're not
-        // sampleable. And this is because in the SSR case, we had to use a renderbuffer to
-        // conserve the multi-sample buffer.
-        transparentPassOutput.linearColor = ppm.resolve(fg, "Resolved Color Buffer",
-                transparentPassOutput.linearColor, { .levels = 1 });
+        if (config.msaa > 1 && !colorGradingConfig.asSubpass) {
+            // We need to do a resolve here because later passes (such as color grading or DoF) will
+            // need to sample from 'output'. However, because we have MSAA, we know we're not
+            // sampleable. And this is because in the SSR case, we had to use a renderbuffer to
+            // conserve the multi-sample buffer.
+            transparentPassOutput.linearColor = ppm.resolve(fg, "Resolved Color Buffer",
+                    transparentPassOutput.linearColor, { .levels = 1 });
+        }
+        return transparentPassOutput;
    }
-    return transparentPassOutput;
+
+    return std::nullopt;
 }

 UTILS_NOINLINE
@@ -26,18 +26,17 @@
 #include <filament/Viewport.h>

 #include <backend/DriverEnums.h>
-#include <backend/Handle.h>
+#include <backend/PixelBufferDescriptor.h>

 #include <math/vec2.h>
 #include <math/vec4.h>

 #include <stdint.h>

-namespace filament {
+#include <optional>
+#include <utility>

-namespace backend {
-class PixelBufferDescriptor;
-}
+namespace filament {

 class FRenderTarget;
 class FrameGraph;
@@ -100,20 +99,18 @@ public:
            PostProcessManager::ColorGradingConfig colorGradingConfig,
            RenderPass::Executor passExecutor) noexcept;

-    static ColorPassOutput refractionPass(
+    static std::optional<ColorPassOutput> refractionPass(
            FrameGraph& fg, FEngine& engine, FView const& view,
            ColorPassInput colorPassInput,
            ColorPassConfig config,
            PostProcessManager::ScreenSpaceRefConfig const& ssrConfig,
            PostProcessManager::ColorGradingConfig colorGradingConfig,
-            RenderPass const& pass, RenderPass::Command const* firstRefractionCommand) noexcept;
+            RenderPass const& pass) noexcept;

    static void readPixels(backend::DriverApi& driver,
            backend::Handle<backend::HwRenderTarget> renderTargetHandle,
            uint32_t xoffset, uint32_t yoffset, uint32_t width, uint32_t height,
            backend::PixelBufferDescriptor&& buffer);
-
-    static RenderPass::Command const* getFirstRefractionCommand(RenderPass const& pass) noexcept;
 };

 } // namespace filament
@@ -140,8 +140,6 @@ Engine* FEngine::create(Builder const& builder) {
                .forceGLES2Context = instance->getConfig().forceGLES2Context,
                .stereoscopicType = instance->getConfig().stereoscopicType,
                .assertNativeWindowIsValid = instance->features.backend.opengl.assert_native_window_is_valid,
-                .metalDisablePanicOnDrawableFailure = instance->getConfig().metalDisablePanicOnDrawableFailure,
-                .gpuContextPriority = instance->getConfig().gpuContextPriority,
        };
        instance->mDriver = platform->createDriver(sharedContext, driverConfig);

@@ -761,8 +759,6 @@ int FEngine::loop() {
            .forceGLES2Context = mConfig.forceGLES2Context,
            .stereoscopicType =  mConfig.stereoscopicType,
            .assertNativeWindowIsValid = features.backend.opengl.assert_native_window_is_valid,
-            .metalDisablePanicOnDrawableFailure = mConfig.metalDisablePanicOnDrawableFailure,
-            .gpuContextPriority = mConfig.gpuContextPriority,
    };
    mDriver = mPlatform->createDriver(mSharedGLContext, driverConfig);

@@ -824,9 +820,9 @@ int FEngine::loop() {
 #if FILAMENT_ENABLE_MATDBG
    if(debug.server) {
        delete debug.server;
-    }
+    } 
 #endif
-#if FILAMENT_ENABLE_FGVIEWER
+#if FILAMENT_ENABLE_FGVIEWER 
    if(debug.fgviewerServer) {
        delete debug.fgviewerServer;
    }
@@ -98,14 +98,6 @@ namespace filament::fgviewer {
 } // namespace filament::fgviewer
 #endif

-// We have added correctness assertions that breaks clients' projects. We add this define to allow
-// for the client's to address these assertions at a more gradual pace.
-#if defined(FILAMENT_RELAXED_CORRECTNESS_ASSERTIONS)
-#define CORRECTNESS_ASSERTION_DEFAULT false
-#else
-#define CORRECTNESS_ASSERTION_DEFAULT true
-#endif
-
 namespace filament {

 class Renderer;
@@ -723,14 +715,10 @@ public:
                bool use_shadow_atlas = false;
            } shadows;
            struct {
-                // TODO: clean-up the following flags (equivalent to setting them to true) when
-                // clients have addressed their usages.
-                bool assert_material_instance_in_use = CORRECTNESS_ASSERTION_DEFAULT;
-                bool assert_destroy_material_before_material_instance =
-                        CORRECTNESS_ASSERTION_DEFAULT;
-                bool assert_vertex_buffer_count_exceeds_8 = CORRECTNESS_ASSERTION_DEFAULT;
-                bool assert_vertex_buffer_attribute_stride_mult_of_4 =
-                        CORRECTNESS_ASSERTION_DEFAULT;
+                // TODO: default the following two flags to true.
+                bool assert_material_instance_in_use = false;
+                bool assert_destroy_material_before_material_instance = false;
+                bool assert_vertex_buffer_count_exceeds_8 = false;
            } debug;
        } engine;
        struct {
@@ -771,9 +759,6 @@ public:
            { "features.engine.debug.assert_vertex_buffer_count_exceeds_8",
              "Assert when a client's number of buffers for a VertexBuffer exceeds 8.",
              &features.engine.debug.assert_vertex_buffer_count_exceeds_8, false },
-            { "features.engine.debug.assert_vertex_buffer_attribute_stride_mult_of_4",
-              "Assert that the attribute stride of a vertex buffer is a multiple of 4.",
-              &features.engine.debug.assert_vertex_buffer_attribute_stride_mult_of_4, false },
    }};

    utils::Slice<const FeatureFlag> getFeatureFlags() const noexcept {
@@ -342,8 +342,24 @@ FMaterial::FMaterial(FEngine& engine, const Builder& builder,

    processBlendingMode(parser);
    processSpecializationConstants(engine, builder, parser);
+    processMutableSpecializationConstants(engine, builder, parser);
    processPushConstants(engine, parser);
    processDescriptorSets(engine, parser);
+
+    switch (mMaterialDomain) {
+        case filament::MaterialDomain::SURFACE:
+            mVariantBits = VARIANT_BITS;
+            break;
+        case filament::MaterialDomain::POST_PROCESS:
+            mVariantBits = POST_PROCESS_VARIANT_BITS;
+            break;
+        case filament::MaterialDomain::COMPUTE:
+            mVariantBits = 0;
+            break;
+    }
+    mCachedPrograms = FixedCapacityVector<backend::Handle<backend::HwProgram>>(
+            1 << (mVariantBits + mMaterialMutableConstants.size()));
+
    precacheDepthVariants(engine);

 #if FILAMENT_ENABLE_MATDBG
@@ -449,13 +465,17 @@ void FMaterial::compile(CompilerPriorityQueue const priority,
    UserVariantFilterMask const variantFilter =
            ~variantSpec & UserVariantFilterMask(UserVariantFilterBit::ALL);

+    int mutableConstantVariations = 1 << mMaterialMutableConstants.size();
+
    if (UTILS_LIKELY(mEngine.getDriverApi().isParallelShaderCompileSupported())) {
        auto const& variants = isVariantLit() ?
                VariantUtils::getLitVariants() : VariantUtils::getUnlitVariants();
        for (auto const variant: variants) {
            if (!variantFilter || variant == Variant::filterUserVariant(variant, variantFilter)) {
                if (hasVariant(variant)) {
-                    prepareProgram(variant, priority);
+                    for (int spec = 0; spec < mutableConstantVariations; spec++) {
+                        prepareProgram(variant, Program::MutableSpecConstantsInfo(spec), priority);
+                    }
                }
            }
        }
@@ -496,6 +516,11 @@ FMaterialInstance* FMaterial::getDefaultInstance() noexcept {
    return mDefaultMaterialInstance;
 }

+bool FMaterial::isCached(Variant const variant,
+        const backend::Program::MutableSpecConstantsInfo mutableSpecConstants) const noexcept {
+    return bool(mCachedPrograms[getCachedProgramIndex(variant, mutableSpecConstants)]);
+}
+
 bool FMaterial::hasParameter(const char* name) const noexcept {
    return mUniformInterfaceBlock.hasField(name) ||
           mSamplerInterfaceBlock.hasSampler(name) ||
@@ -536,14 +561,15 @@ bool FMaterial::hasVariant(Variant const variant) const noexcept {
 }

 void FMaterial::prepareProgramSlow(Variant const variant,
+        const backend::Program::MutableSpecConstantsInfo mutableSpecConstants,
        backend::CompilerPriorityQueue const priorityQueue) const noexcept {
    assert_invariant(mEngine.hasFeatureLevel(mFeatureLevel));
    switch (getMaterialDomain()) {
        case MaterialDomain::SURFACE:
-            getSurfaceProgramSlow(variant, priorityQueue);
+            getSurfaceProgramSlow(variant, mutableSpecConstants, priorityQueue);
            break;
        case MaterialDomain::POST_PROCESS:
-            getPostProcessProgramSlow(variant, priorityQueue);
+            getPostProcessProgramSlow(variant, mutableSpecConstants, priorityQueue);
            break;
        case MaterialDomain::COMPUTE:
            // TODO: implement MaterialDomain::COMPUTE
@@ -552,6 +578,7 @@ void FMaterial::prepareProgramSlow(Variant const variant,
 }

 void FMaterial::getSurfaceProgramSlow(Variant const variant,
+        const backend::Program::MutableSpecConstantsInfo mutableSpecConstants,
        CompilerPriorityQueue const priorityQueue) const noexcept {
    // filterVariant() has already been applied in generateCommands(), shouldn't be needed here
    // if we're unlit, we don't have any bits that correspond to lit materials
@@ -562,25 +589,25 @@ void FMaterial::getSurfaceProgramSlow(Variant const variant,
    Variant const vertexVariant   = Variant::filterVariantVertex(variant);
    Variant const fragmentVariant = Variant::filterVariantFragment(variant);

-    Program pb{ getProgramWithVariants(variant, vertexVariant, fragmentVariant) };
+    Program pb{ getProgramWithVariants(variant, vertexVariant, fragmentVariant, mutableSpecConstants) };
    pb.priorityQueue(priorityQueue);
    pb.multiview(
            mEngine.getConfig().stereoscopicType == StereoscopicType::MULTIVIEW &&
            Variant::isStereoVariant(variant));
-    createAndCacheProgram(std::move(pb), variant);
+    createAndCacheProgram(std::move(pb), variant, mutableSpecConstants);
 }

 void FMaterial::getPostProcessProgramSlow(Variant const variant,
+        const backend::Program::MutableSpecConstantsInfo mutableSpecConstants,
        CompilerPriorityQueue const priorityQueue) const noexcept {
-    Program pb{ getProgramWithVariants(variant, variant, variant) };
+    Program pb{ getProgramWithVariants(variant, variant, variant, mutableSpecConstants) };
    pb.priorityQueue(priorityQueue);
-    createAndCacheProgram(std::move(pb), variant);
+    createAndCacheProgram(std::move(pb), variant, mutableSpecConstants);
 }

-Program FMaterial::getProgramWithVariants(
-        Variant variant,
-        Variant vertexVariant,
-        Variant fragmentVariant) const {
+Program FMaterial::getProgramWithVariants(Variant variant,
+        Variant vertexVariant, Variant fragmentVariant,
+        const backend::Program::MutableSpecConstantsInfo mutableSpecConstants) const {
    FEngine const& engine = mEngine;
    const ShaderModel sm = engine.getShaderModel();
    const bool isNoop = engine.getBackend() == Backend::NOOP;
@@ -641,29 +668,34 @@ Program FMaterial::getProgramWithVariants(
            mProgramDescriptorBindings[+DescriptorSetBindingPoints::PER_RENDERABLE]);
    program.descriptorBindings(+DescriptorSetBindingPoints::PER_MATERIAL,
            mProgramDescriptorBindings[+DescriptorSetBindingPoints::PER_MATERIAL]);
-    program.specializationConstants(mSpecializationConstants);
+    program.specializationConstants(mSpecializationConstants,
+            CONFIG_MAX_RESERVED_SPEC_CONSTANTS + mMaterialConstants.size(), mutableSpecConstants);

    program.pushConstants(ShaderStage::VERTEX, mPushConstants[uint8_t(ShaderStage::VERTEX)]);
    program.pushConstants(ShaderStage::FRAGMENT, mPushConstants[uint8_t(ShaderStage::FRAGMENT)]);

-    program.cacheId(hash::combine(size_t(mCacheId), variant.key));
+    program.cacheId(
+            hash::combine(size_t(mCacheId),
+                    hash::combine(variant.key, mutableSpecConstants.getValue())));

    return program;
 }

-void FMaterial::createAndCacheProgram(Program&& p, Variant const variant) const noexcept {
+void FMaterial::createAndCacheProgram(Program&& p, Variant const variant,
+        Program::MutableSpecConstantsInfo const mutableSpecConstants) const noexcept {
    FEngine const& engine = mEngine;
    DriverApi& driverApi = mEngine.getDriverApi();

    bool const isShared = isSharedVariant(variant);
+    size_t const cacheIndex = getCachedProgramIndex(variant, mutableSpecConstants);

    // Check if the default material has this program cached
    if (isShared) {
        FMaterial const* const pDefaultMaterial = engine.getDefaultMaterial();
        if (pDefaultMaterial) {
-            auto const program = pDefaultMaterial->mCachedPrograms[variant.key];
+            auto const program = pDefaultMaterial->mCachedPrograms[cacheIndex];
            if (program) {
-                mCachedPrograms[variant.key] = program;
+                mCachedPrograms[cacheIndex] = program;
                return;
            }
        }
@@ -672,17 +704,17 @@ void FMaterial::createAndCacheProgram(Program&& p, Variant const variant) const
    auto const program = driverApi.createProgram(std::move(p));
    driverApi.setDebugTag(program.getId(), mName);
    assert_invariant(program);
-    mCachedPrograms[variant.key] = program;
+    mCachedPrograms[cacheIndex] = program;

    // 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 (isShared) {
        FMaterial const* const pDefaultMaterial = engine.getDefaultMaterial();
-        if (pDefaultMaterial && !pDefaultMaterial->mCachedPrograms[variant.key]) {
+        if (pDefaultMaterial && !pDefaultMaterial->mCachedPrograms[cacheIndex]) {
            // set the tag to the default material name
            driverApi.setDebugTag(program.getId(), mName);
-            pDefaultMaterial->mCachedPrograms[variant.key] = program;
+            pDefaultMaterial->mCachedPrograms[cacheIndex] = program;
        }
    }
 }
@@ -730,6 +762,14 @@ size_t FMaterial::getParameters(ParameterInfo* parameters, size_t count) const n
    return count;
 }

+std::optional<uint32_t> FMaterial::getMutableConstantId(std::string_view name) const noexcept {
+    auto const pos = mMutableSpecializationConstantsNameToIndex.find(name);
+    if (pos != mMutableSpecializationConstantsNameToIndex.end()) {
+        return pos->second;
+    }
+    return std::nullopt;
+}
+
 #if FILAMENT_ENABLE_MATDBG

 // Swaps in an edited version of the original package that was used to create the material. The
@@ -788,7 +828,9 @@ void FMaterial::onQueryCallback(void* userdata, VariantList* pActiveVariants) {

 #endif // FILAMENT_ENABLE_MATDBG

-[[nodiscard]] Handle<HwProgram> FMaterial::getProgramWithMATDBG(Variant const variant) const noexcept {
+[[nodiscard]] Handle<HwProgram> FMaterial::getProgramWithMATDBG(Variant const variant,
+        Program::MutableSpecConstantsInfo const mutableSpecConstants) const noexcept {
+    size_t cacheIndex = getCachedProgramIndex(variant, mutableSpecConstants);
 #if FILAMENT_ENABLE_MATDBG
    assert_invariant((size_t)variant.key < VARIANT_COUNT);
    std::unique_lock lock(mActiveProgramsLock);
@@ -803,13 +845,13 @@ void FMaterial::onQueryCallback(void* userdata, VariantList* pActiveVariants) {
    lock.unlock();
    if (isSharedVariant(variant)) {
        FMaterial const* const pDefaultMaterial = mEngine.getDefaultMaterial();
-        if (pDefaultMaterial && pDefaultMaterial->mCachedPrograms[variant.key]) {
-            return pDefaultMaterial->getProgram(variant);
+        if (pDefaultMaterial && pDefaultMaterial->mCachedPrograms[cacheIndex]) {
+            return pDefaultMaterial->getProgram(variant, mutableSpecConstants);
        }
    }
 #endif
-    assert_invariant(mCachedPrograms[variant.key]);
-    return mCachedPrograms[variant.key];
+    assert_invariant(mCachedPrograms[cacheIndex]);
+    return mCachedPrograms[cacheIndex];
 }

 void FMaterial::destroyPrograms(FEngine& engine,
@@ -822,7 +864,7 @@ void FMaterial::destroyPrograms(FEngine& engine,
        case MaterialDomain::SURFACE: {
            if (mIsDefaultMaterial || mHasCustomDepthShader) {
                // default material, or we have custom depth shaders, we destroy all variants
-                for (size_t k = 0, n = VARIANT_COUNT; k < n; ++k) {
+                for (size_t k = 0, n = cachedPrograms.size(); k < n; ++k) {
                    if ((k & variantMask) == variantValue) {
                        // Only destroy if the handle is valid. Not strictly needed, but we have a lot
                        // of variants, and this generates traffic in the command queue.
@@ -840,7 +882,7 @@ void FMaterial::destroyPrograms(FEngine& engine,
                UTILS_UNUSED_IN_RELEASE
                auto const UTILS_NULLABLE pDefaultMaterial = engine.getDefaultMaterial();

-                for (size_t k = 0, n = VARIANT_COUNT; k < n; ++k) {
+                for (size_t k = 0, n = cachedPrograms.size(); k < n; ++k) {
                    if ((k & variantMask) == variantValue) {
                        // Only destroy if the handle is valid. Not strictly needed, but we have a lot
                        // of variant, and this generates traffic in the command queue.
@@ -852,7 +894,7 @@ void FMaterial::destroyPrograms(FEngine& engine,
                                // During Engine::shutdown, auto-cleanup destroys the
                                // default material first
                                assert_invariant(!pDefaultMaterial ||
-                                        pDefaultMaterial->mCachedPrograms[k]);
+                                        pDefaultMaterial->mCachedPrograms[k & (VARIANT_COUNT - 1)]);
                                // we don't own this variant, skip, but clear the entry.
                                cachedPrograms[k].clear();
                                continue;
@@ -866,7 +908,7 @@ void FMaterial::destroyPrograms(FEngine& engine,
            break;
        }
        case MaterialDomain::POST_PROCESS: {
-            for (size_t k = 0, n = POST_PROCESS_VARIANT_COUNT; k < n; ++k) {
+            for (size_t k = 0, n = cachedPrograms.size(); k < n; ++k) {
                if ((k & variantMask) == variantValue) {
                    // Only destroy if the handle is valid. Not strictly needed, but we have a lot
                    // of variant, and this generates traffic in the command queue.
@@ -878,8 +920,13 @@ void FMaterial::destroyPrograms(FEngine& engine,
            break;
        }
        case MaterialDomain::COMPUTE: {
-            // Compute programs don't have variants
-            driverApi.destroyProgram(std::move(cachedPrograms[0]));
+            for (size_t k = 0, n = cachedPrograms.size(); k < n; ++k) {
+                // Only destroy if the handle is valid. Not strictly needed, but we have a lot
+                // of variant, and this generates traffic in the command queue.
+                if (cachedPrograms[k]) {
+                    driverApi.destroyProgram(std::move(cachedPrograms[k]));
+                }
+            }
            break;
        }
    }
@@ -1114,6 +1161,19 @@ void FMaterial::processSpecializationConstants(FEngine& engine, Builder const& b
    }
 }

+void FMaterial::processMutableSpecializationConstants(FEngine& engine, Builder const& builder,
+        MaterialParser const* const parser) {
+    // Older materials won't have a mutable constants chunk, but that's okay.
+    parser->getMutableConstants(&mMaterialMutableConstants);
+    for (size_t i = 0, c = mMaterialMutableConstants.size(); i < c; i++) {
+        auto& item = mMaterialMutableConstants[i];
+        // the key can be a string_view because mMaterialMutableConstants owns the CString
+        std::string_view const key{ item.name.data(), item.name.size() };
+        mMutableSpecializationConstantsNameToIndex[key] = i;
+        mDefaultMutableSpecializationConstants.set(i, item.defaultValue);
+    }
+}
+
 void FMaterial::processPushConstants(FEngine&, MaterialParser const* parser) {
    FixedCapacityVector<Program::PushConstant>& vertexConstants =
            mPushConstants[uint8_t(ShaderStage::VERTEX)];
@@ -1169,7 +1229,8 @@ void FMaterial::precacheDepthVariants(FEngine& engine) {
            }
            assert_invariant(Variant::isValidDepthVariant(variant));
            if (hasVariant(variant)) {
-                prepareProgram(variant);
+                // The default material shouldn't ever have mutable spec constants.
+                prepareProgram(variant, Program::MutableSpecConstantsInfo(0));
            }
        }
        return;
@@ -1182,9 +1243,16 @@ void FMaterial::precacheDepthVariants(FEngine& engine) {
        FMaterial const* const pDefaultMaterial = engine.getDefaultMaterial();
        assert_invariant(pDefaultMaterial);
        auto const allDepthVariants = VariantUtils::getDepthVariants();
+        int mutableConstantVariations = 1 << mMaterialMutableConstants.size();
        for (auto const variant: allDepthVariants) {
            assert_invariant(Variant::isValidDepthVariant(variant));
-            mCachedPrograms[variant.key] = pDefaultMaterial->mCachedPrograms[variant.key];
+            size_t defaultCacheIndex = pDefaultMaterial->getCachedProgramIndex(variant,
+                    Program::MutableSpecConstantsInfo(0));
+            for (int spec = 0; spec < mutableConstantVariations; spec++) {
+                size_t cacheIndex = getCachedProgramIndex(variant,
+                        Program::MutableSpecConstantsInfo(spec));
+                mCachedPrograms[cacheIndex] = pDefaultMaterial->mCachedPrograms[defaultCacheIndex];
+            }
        }
    }
 }
@@ -122,9 +122,8 @@ public:

    FEngine& getEngine() const noexcept  { return mEngine; }

-    bool isCached(Variant const variant) const noexcept {
-        return bool(mCachedPrograms[variant.key]);
-    }
+    bool isCached(Variant const variant,
+            const backend::Program::MutableSpecConstantsInfo mutableSpecConstants) const noexcept;

    void invalidate(Variant::type_t variantMask = 0, Variant::type_t variantValue = 0) noexcept;

@@ -132,26 +131,31 @@ public:
    // Must be called outside of backend render pass.
    // Must be called before getProgram() below.
    void prepareProgram(Variant const variant,
+            backend::Program::MutableSpecConstantsInfo const mutableSpecConstants,
            backend::CompilerPriorityQueue const priorityQueue = CompilerPriorityQueue::HIGH) const noexcept {
        // prepareProgram() is called for each RenderPrimitive in the scene, so it must be efficient.
-        if (UTILS_UNLIKELY(!isCached(variant))) {
-            prepareProgramSlow(variant, priorityQueue);
+        if (UTILS_UNLIKELY(!isCached(variant, mutableSpecConstants))) {
+            prepareProgramSlow(variant, mutableSpecConstants, priorityQueue);
        }
    }

-    // getProgram returns the backend program for the material's given variant.
+    // getProgram returns the backend program for the material's given variant and set of mutable
+    // spec constants.
    // Must be called after prepareProgram().
    [[nodiscard]]
-    backend::Handle<backend::HwProgram> getProgram(Variant const variant) const noexcept {
+    backend::Handle<backend::HwProgram> getProgram(Variant const variant,
+            backend::Program::MutableSpecConstantsInfo const mutableSpecConstants) const noexcept {
 #if FILAMENT_ENABLE_MATDBG
-        return getProgramWithMATDBG(variant);
+        return getProgramWithMATDBG(variant, mutableSpecConstants);
 #endif
-        assert_invariant(mCachedPrograms[variant.key]);
-        return mCachedPrograms[variant.key];
+        size_t index = getCachedProgramIndex(variant, mutableSpecConstants);
+        assert_invariant(mCachedPrograms[index]);
+        return mCachedPrograms[index];
    }

    [[nodiscard]]
-    backend::Handle<backend::HwProgram> getProgramWithMATDBG(Variant variant) const noexcept;
+    backend::Handle<backend::HwProgram> getProgramWithMATDBG(Variant variant,
+            backend::Program::MutableSpecConstantsInfo const mutableSpecConstants) const noexcept;

    bool isVariantLit() const noexcept { return mIsVariantLit; }

@@ -208,6 +212,12 @@ public:
    }
    size_t getParameters(ParameterInfo* parameters, size_t count) const noexcept;

+    uint32_t getMutableConstantCount() const noexcept { return mMaterialMutableConstants.size(); }
+    std::optional<uint32_t> getMutableConstantId(std::string_view name) const noexcept;
+    backend::Program::MutableSpecConstantsInfo getDefaultMutableConstants() const noexcept {
+        return mDefaultMutableSpecializationConstants;
+    }
+
    uint32_t generateMaterialInstanceId() const noexcept { return mMaterialInstanceId++; }

    void destroyPrograms(FEngine& engine,
@@ -261,34 +271,48 @@ public:
 private:
    bool hasVariant(Variant variant) const noexcept;
    void prepareProgramSlow(Variant variant,
+            backend::Program::MutableSpecConstantsInfo mutableSpecConstants,
            CompilerPriorityQueue priorityQueue) const noexcept;
    void getSurfaceProgramSlow(Variant variant,
+            backend::Program::MutableSpecConstantsInfo mutableSpecConstants,
            CompilerPriorityQueue priorityQueue) const noexcept;
    void getPostProcessProgramSlow(Variant variant,
+            backend::Program::MutableSpecConstantsInfo mutableSpecConstants,
            CompilerPriorityQueue priorityQueue) const noexcept;
    backend::Program getProgramWithVariants(Variant variant,
-            Variant vertexVariant, Variant fragmentVariant) const;
+            Variant vertexVariant, Variant fragmentVariant,
+            backend::Program::MutableSpecConstantsInfo mutableSpecConstants) const;

    void processBlendingMode(MaterialParser const* parser);

    void processSpecializationConstants(FEngine& engine, Builder const& builder,
            MaterialParser const* parser);

+    void processMutableSpecializationConstants(FEngine& engine, Builder const& builder,
+            MaterialParser const* parser);
+
    void processPushConstants(FEngine& engine, MaterialParser const* parser);

    void precacheDepthVariants(FEngine& engine);

    void processDescriptorSets(FEngine& engine, MaterialParser const* parser);

-    void createAndCacheProgram(backend::Program&& p, Variant variant) const noexcept;
+    void createAndCacheProgram(backend::Program&& p, Variant variant,
+            backend::Program::MutableSpecConstantsInfo mutableSpecConstants) const noexcept;

    inline bool isSharedVariant(Variant const variant) const {
        return (mMaterialDomain == MaterialDomain::SURFACE) && !mIsDefaultMaterial &&
               !mHasCustomDepthShader && Variant::isValidDepthVariant(variant);
    }

+    inline size_t getCachedProgramIndex(const Variant variant,
+            const backend::Program::MutableSpecConstantsInfo mutableSpecConstants) const noexcept {
+        return static_cast<size_t>(variant.key) |
+                (static_cast<size_t>(mutableSpecConstants.getValue()) << mVariantBits);
+    }
+
    // try to order by frequency of use
-    mutable std::array<backend::Handle<backend::HwProgram>, VARIANT_COUNT> mCachedPrograms;
+    mutable utils::FixedCapacityVector<backend::Handle<backend::HwProgram>> mCachedPrograms;
    DescriptorSetLayout mPerViewDescriptorSetLayout;
    DescriptorSetLayout mPerViewDescriptorSetLayoutVsm;
    DescriptorSetLayout mDescriptorSetLayout;
@@ -324,6 +348,7 @@ private:
    bool mHasCustomDepthShader = false;
    bool mIsDefaultMaterial = false;
    bool mSpecularAntiAliasing = false;
+    uint8_t mVariantBits;

    // reserve some space to construct the default material instance
    mutable FMaterialInstance* mDefaultMaterialInstance = nullptr;
@@ -348,6 +373,13 @@ private:
    // current specialization constants for the HwProgram
    utils::FixedCapacityVector<backend::Program::SpecializationConstant> mSpecializationConstants;

+    // Mutable constants defined by this Material.
+    utils::FixedCapacityVector<MaterialMutableConstant> mMaterialMutableConstants;
+    // A map from the Constant name to the mMutableMaterialConstant index
+    std::unordered_map<std::string_view, uint32_t> mMutableSpecializationConstantsNameToIndex;
+    // Default values for the mutable constants.
+    backend::Program::MutableSpecConstantsInfo mDefaultMutableSpecializationConstants;
+
    // current push constants for the HwProgram
    std::array<utils::FixedCapacityVector<backend::Program::PushConstant>,
            backend::Program::SHADER_TYPE_COUNT>
@@ -63,6 +63,7 @@ FMaterialInstance::FMaterialInstance(FEngine& engine, FMaterial const* material,
                                     const char* name) noexcept
        : mMaterial(material),
          mDescriptorSet("MaterialInstance", material->getDescriptorSetLayout()),
+          mConstants(material->getDefaultMutableConstants()),
          mCulling(CullingMode::BACK),
          mShadowCulling(CullingMode::BACK),
          mDepthFunc(RasterState::DepthFunc::LE),
@@ -128,6 +129,7 @@ FMaterialInstance::FMaterialInstance(FEngine& engine,
          mTextureParameters(other->mTextureParameters),
          mDescriptorSet(other->mDescriptorSet.duplicate(
                "MaterialInstance", mMaterial->getDescriptorSetLayout())),
+          mConstants(other->mConstants),
          mPolygonOffset(other->mPolygonOffset),
          mStencilState(other->mStencilState),
          mMaskThreshold(other->mMaskThreshold),
@@ -31,6 +31,7 @@

 #include <backend/DriverEnums.h>
 #include <backend/Handle.h>
+#include <backend/Program.h>

 #include <utils/BitmaskEnum.h>
 #include <utils/bitset.h>
@@ -66,7 +67,7 @@ public:
    void terminate(FEngine& engine);

    void commitStreamUniformAssociations(FEngine::DriverApi& driver);
-    
+
    void commit(FEngine& engine) const;

    void commit(FEngine::DriverApi& driver) const;
@@ -242,6 +243,10 @@ public:

    using MaterialInstance::setParameter;

+    const backend::Program::MutableSpecConstantsInfo getMutableSpecConstants() const noexcept {
+        return mConstants;
+    }
+
 private:
    friend class FMaterial;
    friend class MaterialInstance;
@@ -264,6 +269,12 @@ private:
    template<typename T>
    T getParameterImpl(std::string_view name) const;

+    template<typename T>
+    void setConstantImpl(std::string_view name, T const& value);
+
+    template<typename T>
+    T getConstantImpl(std::string_view name) const;
+
    // keep these grouped, they're accessed together in the render-loop
    FMaterial const* mMaterial = nullptr;

@@ -277,6 +288,7 @@ private:
    mutable DescriptorSet mDescriptorSet;
    UniformBuffer mUniforms;
    bool mHasStreamUniformAssociations = false;
+    backend::Program::MutableSpecConstantsInfo mConstants;

    backend::PolygonOffset mPolygonOffset{};
    backend::StencilState mStencilState{};
@@ -1125,6 +1125,16 @@ void FRenderer::renderJob(RootArenaScope& rootArenaScope, FView& view) {
    // --------------------------------------------------------------------------------------------
    // Color passes

+    // this makes the viewport relative to xvp
+    // FIXME: we should use 'vp' when rendering directly into the swapchain, but that's hard to
+    //        know at this point. This will usually be the case when post-process is disabled.
+    // FIXME: we probably should take the dynamic scaling into account too
+    // if MSAA is enabled, we end-up rendering in an intermediate buffer. This is the only case where
+    // "!hasPostProcess" doesn't guarantee rendering into the swapchain.
+    const bool useIntermediateBuffer = hasPostProcess || msaaOptions.enabled ||
+          (isRenderingMultiview && engine.debug.stereo.combine_multiview_images);
+    passBuilder.scissorViewport(useIntermediateBuffer ? xvp : vp);
+
    // This one doesn't need to be a FrameGraph pass because it always happens by construction
    // (i.e. it won't be culled, unless everything is culled), so no need to complexify things.
    passBuilder.variant(variant);
@@ -1164,35 +1174,8 @@ void FRenderer::renderJob(RootArenaScope& rootArenaScope, FView& view) {
        passBuilder.renderFlags(renderFlags);
    }

-    // create the pass, which generates all its commands (this is a heavy operation)
    RenderPass const pass{ passBuilder.build(engine, driver) };

-    // now that we have the commands we can figure out if we have refraction commands
-    auto* const firstRefractionCommand = [&view](RenderPass const& pass) {
-        RenderPass::Command const* p = nullptr;
-        if (UTILS_UNLIKELY(view.isScreenSpaceRefractionEnabled() && !pass.empty())) {
-            p = RendererUtils::getFirstRefractionCommand(pass);
-        }
-        return p;
-    }(pass);
-
-    hasScreenSpaceRefraction = firstRefractionCommand != nullptr;
-
-    // this makes the viewport relative to xvp
-    // FIXME: we should use 'vp' when rendering directly into the swapchain, but that's hard to
-    //        know at this point. This will usually be the case when post-process is disabled.
-    // FIXME: we probably should take the dynamic scaling into account too
-    // if MSAA is enabled, we end-up rendering in an intermediate buffer. This is the only case where
-    // "!hasPostProcess" doesn't guarantee rendering into the swapchain.
-    const bool useIntermediateBuffer = hasPostProcess || msaaOptions.enabled ||
-            ssReflectionsOptions.enabled || hasScreenSpaceRefraction ||
-            (isRenderingMultiview && engine.debug.stereo.
-            combine_multiview_images);
-
-    // this is slightly ugly, but conceptually `pass` is const; it's just that we can't set
-    // the scissor viewport during construction
-    const_cast<RenderPass&>(pass).setScissorViewport(useIntermediateBuffer ? xvp : vp);
-
    FrameGraphTexture::Descriptor colorBufferDesc = {
            .width = config.physicalViewport.width,
            .height = config.physicalViewport.height,
@@ -1237,17 +1220,21 @@ void FRenderer::renderJob(RootArenaScope& rootArenaScope, FView& view) {
            },
            colorBufferDesc, config, colorGradingConfigForColor, pass.getExecutor());

-    if (UTILS_UNLIKELY(hasScreenSpaceRefraction)) {
+    if (view.isScreenSpaceRefractionEnabled() && !pass.empty()) {
        // This cancels the colorPass() call above if refraction is active.
        // The color pass + refraction + color-grading as subpass if needed
-        colorPassOutput = RendererUtils::refractionPass(fg, mEngine, view, {
+        auto const output = RendererUtils::refractionPass(fg, mEngine, view, {
                        .shadows = blackboard.get<FrameGraphTexture>("shadows"),
                        .ssao = blackboard.get<FrameGraphTexture>("ssao"),
                        .ssr = ssrConfig.ssr,
                        .structure = structure
                },
-                config, ssrConfig, colorGradingConfigForColor,
-                pass, firstRefractionCommand);
+                config, ssrConfig, colorGradingConfigForColor, pass);
+
+        hasScreenSpaceRefraction = output.has_value();
+        if (hasScreenSpaceRefraction) {
+            colorPassOutput = output.value();
+        }
    }

    if (colorGradingConfig.customResolve) {
@@ -386,9 +386,8 @@ void FTexture::setImage(FEngine& engine, size_t const level,
    FILAMENT_CHECK_PRECONDITION(any(mUsage & Texture::Usage::UPLOADABLE))
            << "Texture is not uploadable.";

-    FILAMENT_CHECK_PRECONDITION(mSampleCount <= 1)
-            << "Operation not supported with multisample ("
-            << unsigned(mSampleCount) << ") texture.";
+    FILAMENT_CHECK_PRECONDITION(mSampleCount <= 1) << "Operation not supported with multisample ("
+                                                   << unsigned(mSampleCount) << ") texture.";

    FILAMENT_CHECK_PRECONDITION(xoffset + width <= valueForLevel(level, mWidth))
            << "xoffset (" << unsigned(xoffset) << ") + width (" << unsigned(width)
@@ -429,46 +428,28 @@ void FTexture::setImage(FEngine& engine, size_t const level,
            << ") > texture depth (" << effectiveTextureDepthOrLayers << ") at level ("
            << unsigned(level) << ")";

-    if (UTILS_UNLIKELY(!width || !height || !depth)) {
-        // The operation is a no-op, return immediately. The PixelBufferDescriptor callback
-        // should be called automatically when the object is destroyed.
-        // The precondition check below assumes width, height, depth non null.
-        return;
-    }
-
    if (p.type != PixelDataType::COMPRESSED) {
        using PBD = PixelBufferDescriptor;
        size_t const stride = p.stride ? p.stride : width;
-        size_t const bpp = PBD::computeDataSize(p.format, p.type, 1, 1, 1);
+        size_t const bpp = PBD::computePixelSize(p.format, p.type);
        size_t const bpr = PBD::computeDataSize(p.format, p.type, stride, 1, p.alignment);
-        size_t const bpl = bpr * height; // TODO: PBD should have a "layer stride"
+        size_t const pbdWidth = stride;
+        // TODO: PBD should have a "layer stride" (using "depth" as a substitute).
+        size_t const pbdDepth = depth;
+        size_t const pbdHeight = p.size / bpr / pbdDepth;
+        assert_invariant(p.size % bpr == 0 && (p.size / bpr) % pbdDepth == 0);
+
        // TODO: PBD should have a p.depth (# layers to skip)
-
-        /* Calculates the byte offset of the last pixel in a 3D sub-region. */
-        auto const calculateLastPixelOffset = [bpp, bpr, bpl](
-                size_t xoff, size_t yoff, size_t zoff,
-                size_t width, size_t height, size_t depth) {
-            // The 0-indexed coordinates of the last pixel are:
-            // x = xoff + width - 1
-            // y = yoff + height - 1
-            // z = zoff + depth - 1
-            // The offset is calculated as: (z * bpl) + (y * bpr) + (x * bpp)
-            return ((zoff + depth  - 1) * bpl) +
-                   ((yoff + height - 1) * bpr) +
-                   ((xoff + width  - 1) * bpp);
-        };
-
-        size_t const lastPixelOffset = calculateLastPixelOffset(
-                p.left, p.top, 0, width, height, depth);
-
-        // make sure the whole last pixel is in the buffer
-        FILAMENT_CHECK_PRECONDITION(lastPixelOffset + bpp <= p.size)
+        FILAMENT_CHECK_PRECONDITION(
+                bpp * (pbdWidth - p.left) * (pbdHeight - p.top) * (pbdDepth - 0) >=
+                bpp * (width - xoffset) * (height - yoffset) * (depth - zoffset))
                << "buffer overflow: (size=" << size_t(p.size) << ", stride=" << size_t(p.stride)
                << ", left=" << unsigned(p.left) << ", top=" << unsigned(p.top)
                << ") smaller than specified region "
                   "{{"
-                << unsigned(xoffset) << "," << unsigned(yoffset) << "," << unsigned(zoffset) << "},{"
-                << unsigned(width) << "," << unsigned(height) << "," << unsigned(depth) << ")}}";
+                << unsigned(xoffset) << "," << unsigned(yoffset) << "," << unsigned(zoffset)
+                << "},{" << unsigned(width) << "," << unsigned(height) << "," << unsigned(depth)
+                << ")}}";
    }

    engine.getDriverApi().update3DImage(mHandle, uint8_t(level), xoffset, yoffset, zoffset, width,
@@ -162,7 +162,8 @@ VertexBuffer* VertexBuffer::Builder::build(Engine& engine) {
        FILAMENT_CHECK_PRECONDITION(mImpl->mBufferCount <= DOCUMENTED_MAX_VERTEX_BUFFER_COUNT)
                << "bufferCount cannot be more than " << DOCUMENTED_MAX_VERTEX_BUFFER_COUNT;
    } else if (mImpl->mBufferCount > DOCUMENTED_MAX_VERTEX_BUFFER_COUNT) {
-        LOG(WARNING) << "bufferCount cannot be more than " << DOCUMENTED_MAX_VERTEX_BUFFER_COUNT;
+        utils::slog.w << "bufferCount cannot be more than " << DOCUMENTED_MAX_VERTEX_BUFFER_COUNT
+                      << utils::io::endl;
    }

    // Next we check if any unused buffer slots have been allocated. This helps prevent errors
@@ -177,15 +178,9 @@ VertexBuffer* VertexBuffer::Builder::build(Engine& engine) {
                << "attribute " << j << " offset=" << attributes[j].offset
                << " is not multiple of 4";

-        FEngine* fengine = static_cast<FEngine*>(&engine);
-        if (fengine->features.engine.debug.assert_vertex_buffer_attribute_stride_mult_of_4) {
-            FILAMENT_CHECK_PRECONDITION((attributes[j].stride & 0x3u) == 0)
-                    << "attribute " << j << " stride=" << attributes[j].stride
-                    << " is not multiple of 4";
-        } else if ((attributes[j].stride & 0x3u) != 0) {
-            LOG(WARNING) << "attribute " << j << " stride=" << attributes[j].stride
-                         << " is not multiple of 4";
-        }
+        FILAMENT_CHECK_PRECONDITION((attributes[j].stride & 0x3u) == 0)
+                << "attribute " << j << " stride=" << attributes[j].stride
+                << " is not multiple of 4";

        if (engine.getActiveFeatureLevel() == FeatureLevel::FEATURE_LEVEL_0) {
            FILAMENT_CHECK_PRECONDITION(!(attributes[j].flags & Attribute::FLAG_INTEGER_TARGET))
@@ -66,7 +66,6 @@ DescriptorSet& DescriptorSet::operator=(DescriptorSet&& rhs) noexcept {
        mDirty = rhs.mDirty;
        mValid = rhs.mValid;
        mSetAfterCommitWarning = rhs.mSetAfterCommitWarning;
-        mSetUndefinedParameterWarning = rhs.mSetUndefinedParameterWarning;
    }
    return *this;
 }
@@ -107,12 +106,11 @@ void DescriptorSet::commitSlow(DescriptorSetLayout const& layout,
    });

    auto const unsetValidDescriptors = layout.getValidDescriptors() & ~mValid;
-    if (UTILS_VERY_UNLIKELY(!unsetValidDescriptors.empty() && !mSetUndefinedParameterWarning)) {
+    if (UTILS_VERY_UNLIKELY(!unsetValidDescriptors.empty())) {
        unsetValidDescriptors.forEachSetBit([&](auto i) {
            LOG(WARNING) << (layout.isSampler(i) ? "Sampler" : "Buffer") << " descriptor " << i
                         << " of " << mName.c_str() << " is not set. Please report this issue.";
        });
-        mSetUndefinedParameterWarning = true;
    }
 }

@@ -110,7 +110,6 @@ private:
    mutable utils::bitset64 mValid;                         //  8
    backend::DescriptorSetHandle mDescriptorSetHandle;      //  4
    mutable bool mSetAfterCommitWarning = false;            //  1
-    mutable bool mSetUndefinedParameterWarning = false;     //  1
    utils::StaticString mName;                              // 16
 };

@@ -8,8 +8,7 @@ material {
        {
            type : sampler2d,
            name : depth,
-            precision: high,
-            unfilterable: true
+            precision: high
        },
        {
            type : float,
@@ -4,8 +4,7 @@ material {
        {
            type : sampler2d,
            name : depth,
-            precision: medium,
-            unfilterable: true
+            precision: medium
        },
        {
            type : float4,
@@ -9,8 +9,7 @@ material {
        {
            type : sampler2d,
            name : depth,
-            precision: high,
-            unfilterable: true
+            precision: high
        },
        {
            type : float4,
@@ -78,3 +77,4 @@ fragment {
        postProcess.color = color;
    }
 }
+
@@ -9,8 +9,7 @@ material {
        {
            type : sampler2d,
            name : depth,
-            precision: medium,
-            unfilterable: true
+            precision: medium
        },
        {
            type : float2,
--- a/Show More
+++ b/Show More