Use WebGPU platform explicitly in shaders rather than rely on the mostly similar cases to Vulkan, with the exception of flipping the Y axis where they are different

filament/backend/test/ShaderGenerator.cpp

@@ -118,7 +118,7 @@ ShaderGenerator::Blob ShaderGenerator::transpileShader(ShaderStage stage, std::s
     } else if (backend == Backend::VULKAN) {
         shader.insert(pos, "#define TARGET_VULKAN_ENVIRONMENT\n");
     } else if (backend == Backend::WEBGPU) {
-        shader.insert(pos, "#define TARGET_VULKAN_ENVIRONMENT\n");
+        shader.insert(pos, "#define TARGET_WEBGPU_ENVIRONMENT\n");
     }
 
     const char* shaderCString = shader.c_str();

filament/backend/test/test_LoadImage.cpp

@@ -52,7 +52,7 @@ layout(location = 0, set = 0) uniform {samplerType} test_tex;
 void main() {
     vec2 fbsize = vec2(512);
     vec2 uv = gl_FragCoord.xy / fbsize;
-#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT)
+#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT) || defined(TARGET_WEBGPU_ENVIRONMENT)
     uv.y = 1.0 - uv.y;
 #endif
     fragColor = vec4(texture(test_tex, uv).rgb, 1.0f);
@@ -73,7 +73,7 @@ float getLayer(in sampler2DArray s) { return 2.0f; }
 void main() {
     vec2 fbsize = vec2(512);
     vec2 uv = gl_FragCoord.xy / fbsize;
-#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT)
+#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT) || defined(TARGET_WEBGPU_ENVIRONMENT)
     uv.y = 1.0 - uv.y;
 #endif
     fragColor = vec4(texture(test_tex, vec3(uv, getLayer(test_tex))).rgb, 1.0f);
@@ -91,7 +91,7 @@ layout(location = 0, set = 0) uniform sampler2D test_tex;
 void main() {
     vec2 fbsize = vec2(512);
     vec2 uv = gl_FragCoord.xy / fbsize;
-#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT)
+#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT) || defined(TARGET_WEBGPU_ENVIRONMENT)
     uv.y = 1.0 - uv.y;
 #endif
     fragColor = vec4(textureLod(test_tex, uv, 1.0f).rgb, 1.0f);

libs/filamat/src/shaders/CodeGenerator.cpp

@@ -176,8 +176,6 @@ utils::io::sstream& CodeGenerator::generateCommonProlog(utils::io::sstream& out,
         // TODO: Handle webgpu here
         case TargetApi::WEBGPU:
             //For now, no differences so inherit the same changes.
-            // TODO Define a separte environment, OR relevant checks
-            out << "#define TARGET_VULKAN_ENVIRONMENT\n";
             out << "#define TARGET_WEBGPU_ENVIRONMENT\n";
             break;
         case TargetApi::ALL:

shaders/src/common_getters.glsl

@@ -79,10 +79,10 @@ highp float getUserTimeMod(float m) {
 /**
  * Transforms a texture UV to make it suitable for a render target attachment.
  *
- * In Vulkan and Metal, texture coords are Y-down but in OpenGL they are Y-up. This wrapper function
- * accounts for these differences. When sampling from non-render targets (i.e. uploaded textures)
- * these differences do not matter because OpenGL has a second piece of backwardness, which is that
- * the first row of texels in glTexImage2D is interpreted as the bottom row.
+ * In Vulkan, WebGPU and Metal, texture coords are Y-down but in OpenGL they are Y-up. This wrapper
+ * function accounts for these differences. When sampling from non-render targets (i.e. uploaded
+ * textures) these differences do not matter because OpenGL has a second piece of backwardness,
+ * which is that the first row of texels in glTexImage2D is interpreted as the bottom row.
  *
  * To protect users from these differences, we recommend that materials in the SURFACE domain
  * leverage this wrapper function when sampling from offscreen render targets.
@@ -90,7 +90,7 @@ highp float getUserTimeMod(float m) {
  * @public-api
  */
 highp vec2 uvToRenderTargetUV(const highp vec2 uv) {
-#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT)
+#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT) || defined(TARGET_WEBGPU_ENVIRONMENT)
     return vec2(uv.x, 1.0 - uv.y);
 #else
     return uv;

shaders/src/common_graphics.fs

@@ -95,7 +95,7 @@ vec3 decodeRGBM(vec4 c) {
 // returns the frag coord in the GL convention with (0, 0) at the bottom-left
 // resolution : width, height
 highp vec2 getFragCoord(const highp vec2 resolution) {
-#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT)
+#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT) || defined(TARGET_WEBGPU_ENVIRONMENT)
     return vec2(gl_FragCoord.x, resolution.y - gl_FragCoord.y);
 #else
     return gl_FragCoord.xy;

shaders/src/post_process_main.vs

@@ -14,7 +14,7 @@ void main() {
     inputs.position.z = inputs.position.z * -0.5 + 0.5;
 
 #if defined(TARGET_VULKAN_ENVIRONMENT)
-    // In Vulkan, clip space is Y-down. In OpenGL and Metal, clip space is Y-up.
+    // In Vulkan, clip space is Y-down. In OpenGL, WebGPU and Metal, clip space is Y-up.
     inputs.position.y = -inputs.position.y;
 #endif
 

shaders/src/surface_getters.vs

@@ -24,7 +24,7 @@ float getObjectUserData() {
 #if __VERSION__ >= 300
 /** @public-api */
 int getVertexIndex() {
-#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT)
+#if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT) || defined(TARGET_WEBGPU_ENVIRONMENT)
     return gl_VertexIndex;
 #else
     return gl_VertexID;

shaders/src/surface_main.vs

@@ -8,7 +8,7 @@
 
 void main() {
 #if defined(FILAMENT_HAS_FEATURE_INSTANCING)
-#   if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT)
+#   if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT) || defined(TARGET_WEBGPU_ENVIRONMENT)
     instance_index = gl_InstanceIndex;
 #   else
     // PowerVR drivers don't initialize gl_InstanceID correctly if it's assigned to the varying