[Impeller] revert usage of foreground blend optimization.

impeller/entity/contents/filters/blend_filter_contents.cc

@@ -394,134 +394,6 @@ std::optional<Entity> BlendFilterContents::CreateForegroundAdvancedBlend(
   return sub_entity;
 }
 
-std::optional<Entity> BlendFilterContents::CreateForegroundPorterDuffBlend(
-    const std::shared_ptr<FilterInput>& input,
-    const ContentContext& renderer,
-    const Entity& entity,
-    const Rect& coverage,
-    Color foreground_color,
-    BlendMode blend_mode,
-    std::optional<Scalar> alpha,
-    ColorFilterContents::AbsorbOpacity absorb_opacity) const {
-  if (blend_mode == BlendMode::kClear) {
-    return std::nullopt;
-  }
-
-  if (blend_mode == BlendMode::kSource) {
-    auto contents = std::make_shared<SolidColorContents>();
-    contents->SetGeometry(Geometry::MakeRect(coverage));
-    contents->SetColor(foreground_color);
-
-    Entity foreground_entity;
-    foreground_entity.SetBlendMode(entity.GetBlendMode());
-    foreground_entity.SetClipDepth(entity.GetClipDepth());
-    foreground_entity.SetContents(std::move(contents));
-    return foreground_entity;
-  }
-
-  auto dst_snapshot =
-      input->GetSnapshot("ForegroundPorterDuffBlend", renderer, entity);
-  if (!dst_snapshot.has_value()) {
-    return std::nullopt;
-  }
-
-  if (blend_mode == BlendMode::kDestination) {
-    return Entity::FromSnapshot(dst_snapshot.value(), entity.GetBlendMode(),
-                                entity.GetClipDepth());
-  }
-
-  RenderProc render_proc = [foreground_color, coverage, dst_snapshot,
-                            blend_mode, absorb_opacity, alpha](
-                               const ContentContext& renderer,
-                               const Entity& entity, RenderPass& pass) -> bool {
-    using VS = PorterDuffBlendPipeline::VertexShader;
-    using FS = PorterDuffBlendPipeline::FragmentShader;
-
-    auto& host_buffer = renderer.GetTransientsBuffer();
-
-    auto maybe_dst_uvs = dst_snapshot->GetCoverageUVs(coverage);
-    if (!maybe_dst_uvs.has_value()) {
-      return false;
-    }
-    auto dst_uvs = maybe_dst_uvs.value();
-
-    auto size = coverage.GetSize();
-    auto origin = coverage.GetOrigin();
-    auto color = foreground_color.Premultiply();
-    VertexBufferBuilder<VS::PerVertexData> vtx_builder;
-    vtx_builder.AddVertices({
-        {origin, dst_uvs[0], color},
-        {Point(origin.x + size.width, origin.y), dst_uvs[1], color},
-        {Point(origin.x, origin.y + size.height), dst_uvs[2], color},
-        {Point(origin.x + size.width, origin.y + size.height), dst_uvs[3],
-         color},
-    });
-    auto vtx_buffer = vtx_builder.CreateVertexBuffer(host_buffer);
-
-#ifdef IMPELLER_DEBUG
-    pass.SetCommandLabel(SPrintF("Foreground PorterDuff Blend Filter (%s)",
-                                 BlendModeToString(blend_mode)));
-#endif  // IMPELLER_DEBUG
-    pass.SetVertexBuffer(std::move(vtx_buffer));
-    pass.SetStencilReference(entity.GetClipDepth());
-    auto options = OptionsFromPass(pass);
-    options.primitive_type = PrimitiveType::kTriangleStrip;
-    pass.SetPipeline(renderer.GetPorterDuffBlendPipeline(options));
-
-    FS::FragInfo frag_info;
-    VS::FrameInfo frame_info;
-    frame_info.depth = entity.GetShaderClipDepth();
-
-    auto dst_sampler_descriptor = dst_snapshot->sampler_descriptor;
-    if (renderer.GetDeviceCapabilities().SupportsDecalSamplerAddressMode()) {
-      dst_sampler_descriptor.width_address_mode = SamplerAddressMode::kDecal;
-      dst_sampler_descriptor.height_address_mode = SamplerAddressMode::kDecal;
-    }
-    const std::unique_ptr<const Sampler>& dst_sampler =
-        renderer.GetContext()->GetSamplerLibrary()->GetSampler(
-            dst_sampler_descriptor);
-    FS::BindTextureSamplerDst(pass, dst_snapshot->texture, dst_sampler);
-    frame_info.texture_sampler_y_coord_scale =
-        dst_snapshot->texture->GetYCoordScale();
-
-    frag_info.input_alpha =
-        absorb_opacity == ColorFilterContents::AbsorbOpacity::kYes
-            ? dst_snapshot->opacity * alpha.value_or(1.0)
-            : 1.0;
-    frag_info.output_alpha = 1.0;
-
-    auto blend_coefficients =
-        kPorterDuffCoefficients[static_cast<int>(blend_mode)];
-    frag_info.src_coeff = blend_coefficients[0];
-    frag_info.src_coeff_dst_alpha = blend_coefficients[1];
-    frag_info.dst_coeff = blend_coefficients[2];
-    frag_info.dst_coeff_src_alpha = blend_coefficients[3];
-    frag_info.dst_coeff_src_color = blend_coefficients[4];
-
-    FS::BindFragInfo(pass, host_buffer.EmplaceUniform(frag_info));
-
-    frame_info.mvp = pass.GetOrthographicTransform() * entity.GetTransform();
-
-    auto uniform_view = host_buffer.EmplaceUniform(frame_info);
-    VS::BindFrameInfo(pass, uniform_view);
-
-    return pass.Draw().ok();
-  };
-
-  CoverageProc coverage_proc =
-      [coverage](const Entity& entity) -> std::optional<Rect> {
-    return coverage.TransformBounds(entity.GetTransform());
-  };
-
-  auto contents = AnonymousContents::Make(render_proc, coverage_proc);
-
-  Entity sub_entity;
-  sub_entity.SetContents(std::move(contents));
-  sub_entity.SetClipDepth(entity.GetClipDepth());
-
-  return sub_entity;
-}
-
 static std::optional<Entity> PipelineBlend(
     const FilterInput::Vector& inputs,
     const ContentContext& renderer,
@@ -740,12 +612,6 @@ std::optional<Entity> BlendFilterContents::RenderFilter(
   }
 
   if (blend_mode_ <= Entity::kLastPipelineBlendMode) {
-    if (inputs.size() == 1 && foreground_color_.has_value() &&
-        GetAbsorbOpacity() == ColorFilterContents::AbsorbOpacity::kYes) {
-      return CreateForegroundPorterDuffBlend(
-          inputs[0], renderer, entity, coverage, foreground_color_.value(),
-          blend_mode_, GetAlpha(), GetAbsorbOpacity());
-    }
     return PipelineBlend(inputs, renderer, entity, coverage, blend_mode_,
                          foreground_color_, GetAbsorbOpacity(), GetAlpha());
   }

impeller/entity/contents/filters/blend_filter_contents.h

@@ -78,20 +78,6 @@ class BlendFilterContents : public ColorFilterContents {
       std::optional<Scalar> alpha,
       ColorFilterContents::AbsorbOpacity absorb_opacity) const;
 
-  /// @brief Optimized porter-duff blend that avoids a second subpass when there
-  ///        is only a single input and a foreground color.
-  ///
-  /// These contents cannot absorb opacity.
-  std::optional<Entity> CreateForegroundPorterDuffBlend(
-      const std::shared_ptr<FilterInput>& input,
-      const ContentContext& renderer,
-      const Entity& entity,
-      const Rect& coverage,
-      Color foreground_color,
-      BlendMode blend_mode,
-      std::optional<Scalar> alpha,
-      ColorFilterContents::AbsorbOpacity absorb_opacity) const;
-
   BlendMode blend_mode_ = BlendMode::kSourceOver;
   AdvancedBlendProc advanced_blend_proc_;
   std::optional<Color> foreground_color_;