[CP][Impeller] Use depth transform in framebuffer blend entities. (#53951) (#54478)

\Without this the depth always ends up being a very large z depth of 0.5, which can cause clips to be ignored.

Author: Jonah Williams

impeller/display_list/aiks_dl_clip_unittests.cc

@@ -117,5 +117,30 @@ TEST_P(AiksTest, ClipsUseCurrentTransform) {
   ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
 }
 
+/// If correct, this test should draw a green circle. If any red is visible,
+/// there is a depth bug.
+TEST_P(AiksTest, FramebufferBlendsRespectClips) {
+  DisplayListBuilder builder;
+
+  // Clear the whole canvas with white.
+  DlPaint paint;
+  paint.setColor(DlColor::kWhite());
+  builder.DrawPaint(paint);
+
+  builder.ClipPath(SkPath::Circle(150, 150, 50), DlCanvas::ClipOp::kIntersect);
+
+  // Draw a red rectangle that should not show through the circle clip.
+  paint.setColor(DlColor::kRed());
+  paint.setBlendMode(DlBlendMode::kMultiply);
+  builder.DrawRect(SkRect::MakeXYWH(100, 100, 100, 100), paint);
+
+  // Draw a green circle that shows through the clip.
+  paint.setColor(DlColor::kGreen());
+  paint.setBlendMode(DlBlendMode::kSrcOver);
+  builder.DrawCircle(SkPoint::Make(150, 150), 50, paint);
+
+  ASSERT_TRUE(OpenPlaygroundHere(builder.Build()));
+}
+
 }  // namespace testing
 }  // namespace impeller

impeller/entity/contents/filters/blend_filter_contents.cc

@@ -365,7 +365,8 @@ std::optional<Entity> BlendFilterContents::CreateForegroundAdvancedBlend(
     FS::BindTextureSamplerDst(pass, dst_snapshot->texture, dst_sampler);
     frame_info.dst_y_coord_scale = dst_snapshot->texture->GetYCoordScale();
 
-    frame_info.mvp = pass.GetOrthographicTransform() * dst_snapshot->transform;
+    frame_info.mvp = Entity::GetShaderTransform(entity.GetShaderClipDepth(),
+                                                pass, dst_snapshot->transform);
 
     blend_info.dst_input_alpha =
         absorb_opacity == ColorFilterContents::AbsorbOpacity::kYes
@@ -454,7 +455,8 @@ std::optional<Entity> BlendFilterContents::CreateForegroundPorterDuffBlend(
     FS::FragInfo frag_info;
     VS::FrameInfo frame_info;
 
-    frame_info.mvp = pass.GetOrthographicTransform() * dst_snapshot->transform;
+    frame_info.mvp = Entity::GetShaderTransform(entity.GetShaderClipDepth(),
+                                                pass, dst_snapshot->transform);
 
     auto dst_sampler_descriptor = dst_snapshot->sampler_descriptor;
     if (renderer.GetDeviceCapabilities().SupportsDecalSamplerAddressMode()) {

testing/impeller_golden_tests_output.txt

@@ -641,6 +641,9 @@ impeller_Play_AiksTest_ForegroundPipelineBlendAppliesTransformCorrectly_Vulkan.p
 impeller_Play_AiksTest_FramebufferAdvancedBlendCoverage_Metal.png
 impeller_Play_AiksTest_FramebufferAdvancedBlendCoverage_OpenGLES.png
 impeller_Play_AiksTest_FramebufferAdvancedBlendCoverage_Vulkan.png
+impeller_Play_AiksTest_FramebufferBlendsRespectClips_Metal.png
+impeller_Play_AiksTest_FramebufferBlendsRespectClips_OpenGLES.png
+impeller_Play_AiksTest_FramebufferBlendsRespectClips_Vulkan.png
 impeller_Play_AiksTest_GaussianBlurAnimatedBackdrop_Metal.png
 impeller_Play_AiksTest_GaussianBlurAnimatedBackdrop_OpenGLES.png
 impeller_Play_AiksTest_GaussianBlurAnimatedBackdrop_Vulkan.png