Change External Texture YUV-To-RGB Matrix To Be Optional

Changes the yuv-to-rgb constant matrix to be optional during external
texture creation because it is not necessary for single-plane scenarios.

Bug: dawn:1082
Change-Id: I543f4009e58f1571b0be80abb6b464b2b8c9d749
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/91280
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>

dawn.json

@@ -1345,7 +1345,7 @@
             {"name": "plane 0", "type": "texture view"},
             {"name": "plane 1", "type": "texture view", "optional": true},
             {"name": "yuv to rgb conversion matrix", "type": "float", "annotation": "const*",
-                "length": 12},
+                "length": 12, "optional": true},
             {"name": "src transfer function parameters", "type": "float", "annotation": "const*",
                 "length": 7},
             {"name": "dst transfer function parameters", "type": "float", "annotation": "const*",

src/dawn/native/ExternalTexture.cpp

@@ -57,9 +57,6 @@ MaybeError ValidateExternalTextureDescriptor(const DeviceBase* device,
 
     wgpu::TextureFormat plane0Format = descriptor->plane0->GetFormat().format;
 
-    DAWN_INVALID_IF(!descriptor->yuvToRgbConversionMatrix,
-                    "The YUV-to-RGB conversion matrix must be non-null.");
-
     DAWN_INVALID_IF(!descriptor->gamutConversionMatrix,
                     "The gamut conversion matrix must be non-null.");
 
@@ -69,11 +66,15 @@ MaybeError ValidateExternalTextureDescriptor(const DeviceBase* device,
     DAWN_INVALID_IF(!descriptor->dstTransferFunctionParameters,
                     "The destination transfer function parameters must be non-null.");
 
-    if (descriptor->plane1) {
     DAWN_INVALID_IF(descriptor->colorSpace != wgpu::PredefinedColorSpace::Srgb,
                     "The specified color space (%s) is not %s.", descriptor->colorSpace,
                     wgpu::PredefinedColorSpace::Srgb);
 
+    if (descriptor->plane1) {
+        DAWN_INVALID_IF(
+            !descriptor->yuvToRgbConversionMatrix,
+            "When more than one plane is set, the YUV-to-RGB conversion matrix must be non-null.");
+
         DAWN_TRY(device->ValidateObject(descriptor->plane1));
         wgpu::TextureFormat plane1Format = descriptor->plane1->GetFormat().format;
 
@@ -157,8 +158,12 @@ MaybeError ExternalTextureBase::Initialize(DeviceBase* device,
 
     // YUV-to-RGB conversion is performed by multiplying the source YUV values with a 4x3 matrix
     // passed from Chromium. The matrix was originally sourced from /skia/src/core/SkYUVMath.cpp.
+    // This matrix is only used in multiplanar scenarios.
+    if (params.numPlanes == 2) {
+        ASSERT(descriptor->yuvToRgbConversionMatrix);
         const float* yMat = descriptor->yuvToRgbConversionMatrix;
         std::copy(yMat, yMat + 12, params.yuvToRgbConversionMatrix.begin());
+    }
 
     // Gamut correction is performed by multiplying a 3x3 matrix passed from Chromium. The
     // matrix was computed by multiplying the appropriate source and destination gamut

src/dawn/tests/unittests/validation/ExternalTextureTests.cpp

@@ -157,7 +157,7 @@ TEST_F(ExternalTextureTest, CreateExternalTextureValidation) {
 
 TEST_F(ExternalTextureTest, CreateExternalTextureConstantValueValidation) {
     DAWN_SKIP_TEST_IF(UsesWire());
-    // Creating an external texture without a YUV-to-RGB matrix should fail.
+    // Creating a single plane external texture without a YUV-to-RGB matrix should pass.
     {
         wgpu::TextureDescriptor textureDescriptor = CreateTextureDescriptor();
         wgpu::Texture texture = device.CreateTexture(&textureDescriptor);
@@ -165,6 +165,22 @@ TEST_F(ExternalTextureTest, CreateExternalTextureConstantValueValidation) {
         wgpu::ExternalTextureDescriptor externalDesc = CreateDefaultExternalTextureDescriptor();
         externalDesc.plane0 = texture.CreateView();
         externalDesc.yuvToRgbConversionMatrix = nullptr;
+        device.CreateExternalTexture(&externalDesc);
+    }
+
+    // Creating a multiplanar external texture without a YUV-to-RGB matrix should fail.
+    {
+        wgpu::TextureDescriptor plane0TextureDescriptor =
+            CreateTextureDescriptor(kBiplanarPlane0Format);
+        wgpu::TextureDescriptor plane1TextureDescriptor =
+            CreateTextureDescriptor(kBiplanarPlane1Format);
+        wgpu::Texture texture0 = device.CreateTexture(&plane0TextureDescriptor);
+        wgpu::Texture texture1 = device.CreateTexture(&plane1TextureDescriptor);
+
+        wgpu::ExternalTextureDescriptor externalDesc = CreateDefaultExternalTextureDescriptor();
+        externalDesc.plane0 = texture0.CreateView();
+        externalDesc.plane1 = texture1.CreateView();
+        externalDesc.yuvToRgbConversionMatrix = nullptr;
         ASSERT_DEVICE_ERROR(device.CreateExternalTexture(&externalDesc));
     }