[Impeller] organize texture shaders / delete blend.frag + external_texture_fill (flutter#52137)

* Deletes blend.frag/vert . This was identical to the existing texture_fill shader.
* Move alpha to frag info and stop passing as varying.
~~* Deletes strict src rect fragment shader. We should be able to compute the UVs on the CPU, which is trivial since this is only used for rectangular draws.~~
* Deletes external texture fill in favor of tiled texture external fill. The former shader is marginally faster, but we don't use it since we don't correctly check for the right extensions needed for non-emulated sampling modes with external textures on GLES. Easier to just always use emulated tile modes

Author: Jonah Williams

ci/licenses_golden/licenses_flutter

@@ -40372,8 +40372,6 @@ ORIGIN: ../../../flutter/impeller/entity/render_target_cache.cc + ../../../flutt
 ORIGIN: ../../../flutter/impeller/entity/render_target_cache.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/blending/advanced_blend.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/blending/advanced_blend.vert + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/entity/shaders/blending/blend.frag + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/entity/shaders/blending/blend.vert + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/blending/blend_select.glsl + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/blending/framebuffer_blend.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/blending/framebuffer_blend.vert + ../../../flutter/LICENSE
@@ -40418,7 +40416,6 @@ ORIGIN: ../../../flutter/impeller/entity/shaders/solid_fill.frag + ../../../flut
 ORIGIN: ../../../flutter/impeller/entity/shaders/solid_fill.vert + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/texture_fill.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/texture_fill.vert + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/entity/shaders/texture_fill_external.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/texture_fill_strict_src.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/tiled_texture_fill.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/tiled_texture_fill_external.frag + ../../../flutter/LICENSE
@@ -43255,8 +43252,6 @@ FILE: ../../../flutter/impeller/entity/render_target_cache.cc
 FILE: ../../../flutter/impeller/entity/render_target_cache.h
 FILE: ../../../flutter/impeller/entity/shaders/blending/advanced_blend.frag
 FILE: ../../../flutter/impeller/entity/shaders/blending/advanced_blend.vert
-FILE: ../../../flutter/impeller/entity/shaders/blending/blend.frag
-FILE: ../../../flutter/impeller/entity/shaders/blending/blend.vert
 FILE: ../../../flutter/impeller/entity/shaders/blending/blend_select.glsl
 FILE: ../../../flutter/impeller/entity/shaders/blending/framebuffer_blend.frag
 FILE: ../../../flutter/impeller/entity/shaders/blending/framebuffer_blend.vert
@@ -43301,7 +43296,6 @@ FILE: ../../../flutter/impeller/entity/shaders/solid_fill.frag
 FILE: ../../../flutter/impeller/entity/shaders/solid_fill.vert
 FILE: ../../../flutter/impeller/entity/shaders/texture_fill.frag
 FILE: ../../../flutter/impeller/entity/shaders/texture_fill.vert
-FILE: ../../../flutter/impeller/entity/shaders/texture_fill_external.frag
 FILE: ../../../flutter/impeller/entity/shaders/texture_fill_strict_src.frag
 FILE: ../../../flutter/impeller/entity/shaders/tiled_texture_fill.frag
 FILE: ../../../flutter/impeller/entity/shaders/tiled_texture_fill_external.frag

impeller/entity/BUILD.gn

@@ -16,8 +16,6 @@ impeller_shaders("entity_shaders") {
   shaders = [
     "shaders/blending/advanced_blend.vert",
     "shaders/blending/advanced_blend.frag",
-    "shaders/blending/blend.frag",
-    "shaders/blending/blend.vert",
     "shaders/border_mask_blur.frag",
     "shaders/border_mask_blur.vert",
     "shaders/clip.frag",
@@ -41,10 +39,9 @@ impeller_shaders("entity_shaders") {
     "shaders/gradients/sweep_gradient_fill.frag",
     "shaders/texture_fill.frag",
     "shaders/texture_fill.vert",
-    "shaders/texture_fill_external.frag",
-    "shaders/texture_fill_strict_src.frag",
     "shaders/tiled_texture_fill.frag",
     "shaders/tiled_texture_fill_external.frag",
+    "shaders/texture_fill_strict_src.frag",
     "shaders/vertices.frag",
     "shaders/blending/porter_duff_blend.frag",
     "shaders/blending/porter_duff_blend.vert",

impeller/entity/contents/atlas_contents.cc

@@ -405,12 +405,16 @@ bool AtlasTextureContents::Render(const ContentContext& renderer,
   VS::FrameInfo frame_info;
   frame_info.mvp = entity.GetShaderTransform(pass);
   frame_info.texture_sampler_y_coord_scale = texture->GetYCoordScale();
-  frame_info.alpha = alpha_;
 
   auto options = OptionsFromPassAndEntity(pass, entity);
   pass.SetPipeline(renderer.GetTexturePipeline(options));
   pass.SetVertexBuffer(vertex_builder.CreateVertexBuffer(host_buffer));
   VS::BindFrameInfo(pass, host_buffer.EmplaceUniform(frame_info));
+
+  FS::FragInfo frag_info;
+  frag_info.alpha = alpha_;
+
+  FS::BindFragInfo(pass, host_buffer.EmplaceUniform(frag_info));
   FS::BindTextureSampler(pass, texture,
                          renderer.GetContext()->GetSamplerLibrary()->GetSampler(
                              parent_.GetSamplerDescriptor()));

impeller/entity/contents/content_context.cc

@@ -421,7 +421,6 @@ ContentContext::ContentContext(
       {static_cast<Scalar>(BlendSelectValues::kSoftLight), supports_decal});
 
   rrect_blur_pipelines_.CreateDefault(*context_, options_trianglestrip);
-  texture_blend_pipelines_.CreateDefault(*context_, options);
   texture_strict_src_pipelines_.CreateDefault(*context_, options);
   position_uv_pipelines_.CreateDefault(*context_, options);
   tiled_texture_pipelines_.CreateDefault(*context_, options);
@@ -448,9 +447,6 @@ ContentContext::ContentContext(
                                              {supports_decal});
   // GLES only shader that is unsupported on macOS.
 #if defined(IMPELLER_ENABLE_OPENGLES) && !defined(FML_OS_MACOSX)
-  if (GetContext()->GetBackendType() == Context::BackendType::kOpenGLES) {
-    texture_external_pipelines_.CreateDefault(*context_, options);
-  }
   if (GetContext()->GetBackendType() == Context::BackendType::kOpenGLES) {
     tiled_texture_external_pipelines_.CreateDefault(*context_, options);
   }

impeller/entity/contents/content_context.h

@@ -29,8 +29,6 @@
 #include "impeller/entity/checkerboard.vert.h"
 #endif  // IMPELLER_DEBUG
 
-#include "impeller/entity/blend.frag.h"
-#include "impeller/entity/blend.vert.h"
 #include "impeller/entity/border_mask_blur.frag.h"
 #include "impeller/entity/border_mask_blur.vert.h"
 #include "impeller/entity/clip.frag.h"
@@ -84,7 +82,6 @@
 #include "impeller/entity/framebuffer_blend.vert.h"
 
 #ifdef IMPELLER_ENABLE_OPENGLES
-#include "impeller/entity/texture_fill_external.frag.h"
 #include "impeller/entity/tiled_texture_fill_external.frag.h"
 #endif  // IMPELLER_ENABLE_OPENGLES
 
@@ -127,8 +124,6 @@ using SweepGradientSSBOFillPipeline =
                          SweepGradientSsboFillFragmentShader>;
 using RRectBlurPipeline =
     RenderPipelineHandle<RrectBlurVertexShader, RrectBlurFragmentShader>;
-using BlendPipeline =
-    RenderPipelineHandle<BlendVertexShader, BlendFragmentShader>;
 using TexturePipeline =
     RenderPipelineHandle<TextureFillVertexShader, TextureFillFragmentShader>;
 using TextureStrictSrcPipeline =
@@ -261,10 +256,6 @@ using PointsComputeShaderPipeline = ComputePipelineBuilder<PointsComputeShader>;
 using UvComputeShaderPipeline = ComputePipelineBuilder<UvComputeShader>;
 
 #ifdef IMPELLER_ENABLE_OPENGLES
-using TextureExternalPipeline =
-    RenderPipelineHandle<TextureFillVertexShader,
-                         TextureFillExternalFragmentShader>;
-
 using TiledTextureExternalPipeline =
     RenderPipelineHandle<TextureFillVertexShader,
                          TiledTextureFillExternalFragmentShader>;
@@ -468,11 +459,6 @@ class ContentContext {
     return GetPipeline(solid_fill_pipelines_, opts);
   }
 
-  std::shared_ptr<Pipeline<PipelineDescriptor>> GetBlendPipeline(
-      ContentContextOptions opts) const {
-    return GetPipeline(texture_blend_pipelines_, opts);
-  }
-
   std::shared_ptr<Pipeline<PipelineDescriptor>> GetTexturePipeline(
       ContentContextOptions opts) const {
     return GetPipeline(texture_pipelines_, opts);
@@ -484,13 +470,6 @@ class ContentContext {
   }
 
 #ifdef IMPELLER_ENABLE_OPENGLES
-  std::shared_ptr<Pipeline<PipelineDescriptor>> GetTextureExternalPipeline(
-      ContentContextOptions opts) const {
-    FML_DCHECK(GetContext()->GetBackendType() ==
-               Context::BackendType::kOpenGLES);
-    return GetPipeline(texture_external_pipelines_, opts);
-  }
-
   std::shared_ptr<Pipeline<PipelineDescriptor>> GetTiledTextureExternalPipeline(
       ContentContextOptions opts) const {
     FML_DCHECK(GetContext()->GetBackendType() ==
@@ -947,11 +926,9 @@ class ContentContext {
   mutable Variants<SweepGradientSSBOFillPipeline>
       sweep_gradient_ssbo_fill_pipelines_;
   mutable Variants<RRectBlurPipeline> rrect_blur_pipelines_;
-  mutable Variants<BlendPipeline> texture_blend_pipelines_;
   mutable Variants<TexturePipeline> texture_pipelines_;
   mutable Variants<TextureStrictSrcPipeline> texture_strict_src_pipelines_;
 #ifdef IMPELLER_ENABLE_OPENGLES
-  mutable Variants<TextureExternalPipeline> texture_external_pipelines_;
   mutable Variants<TiledTextureExternalPipeline>
       tiled_texture_external_pipelines_;
 #endif  // IMPELLER_ENABLE_OPENGLES

impeller/entity/contents/filters/blend_filter_contents.cc

@@ -505,8 +505,8 @@ static std::optional<Entity> PipelineBlend(
     std::optional<Color> foreground_color,
     ColorFilterContents::AbsorbOpacity absorb_opacity,
     std::optional<Scalar> alpha) {
-  using VS = BlendPipeline::VertexShader;
-  using FS = BlendPipeline::FragmentShader;
+  using VS = TexturePipeline::VertexShader;
+  using FS = TexturePipeline::FragmentShader;
 
   auto dst_snapshot =
       inputs[0]->GetSnapshot("PipelineBlend(Dst)", renderer, entity);
@@ -552,7 +552,7 @@ static std::optional<Entity> PipelineBlend(
       const std::unique_ptr<const Sampler>& sampler =
           renderer.GetContext()->GetSamplerLibrary()->GetSampler(
               input->sampler_descriptor);
-      FS::BindTextureSamplerSrc(pass, input->texture, sampler);
+      FS::BindTextureSampler(pass, input->texture, sampler);
 
       auto size = input->texture->GetSize();
       VertexBufferBuilder<VS::PerVertexData> vtx_builder;
@@ -572,7 +572,7 @@ static std::optional<Entity> PipelineBlend(
           input->texture->GetYCoordScale();
 
       FS::FragInfo frag_info;
-      frag_info.input_alpha =
+      frag_info.alpha =
           absorb_opacity == ColorFilterContents::AbsorbOpacity::kYes
               ? input->opacity
               : 1.0;
@@ -584,7 +584,7 @@ static std::optional<Entity> PipelineBlend(
 
     // Draw the first texture using kSource.
     options.blend_mode = BlendMode::kSource;
-    pass.SetPipeline(renderer.GetBlendPipeline(options));
+    pass.SetPipeline(renderer.GetTexturePipeline(options));
     if (!add_blend_command(dst_snapshot)) {
       return true;
     }
@@ -593,7 +593,7 @@ static std::optional<Entity> PipelineBlend(
 
     if (inputs.size() >= 2) {
       options.blend_mode = blend_mode;
-      pass.SetPipeline(renderer.GetBlendPipeline(options));
+      pass.SetPipeline(renderer.GetTexturePipeline(options));
 
       for (auto texture_i = inputs.begin() + 1; texture_i < inputs.end();
            texture_i++) {

impeller/entity/contents/filters/gaussian_blur_filter_contents.cc

@@ -95,7 +95,9 @@ fml::StatusOr<RenderTarget> MakeDownsampleSubpass(
         TextureFillVertexShader::FrameInfo frame_info;
         frame_info.mvp = Matrix::MakeOrthographic(ISize(1, 1));
         frame_info.texture_sampler_y_coord_scale = 1.0;
-        frame_info.alpha = 1.0;
+
+        TextureFillFragmentShader::FragInfo frag_info;
+        frag_info.alpha = 1.0;
 
         BindVertices<TextureFillVertexShader>(pass, host_buffer,
                                               {
@@ -111,6 +113,8 @@ fml::StatusOr<RenderTarget> MakeDownsampleSubpass(
         linear_sampler_descriptor.min_filter = MinMagFilter::kLinear;
         TextureFillVertexShader::BindFrameInfo(
             pass, host_buffer.EmplaceUniform(frame_info));
+        TextureFillFragmentShader::BindFragInfo(
+            pass, host_buffer.EmplaceUniform(frag_info));
         TextureFillFragmentShader::BindTextureSampler(
             pass, input_texture,
             renderer.GetContext()->GetSamplerLibrary()->GetSampler(

impeller/entity/contents/texture_contents.cc

@@ -13,7 +13,8 @@
 #include "impeller/entity/entity.h"
 #include "impeller/entity/texture_fill.frag.h"
 #include "impeller/entity/texture_fill.vert.h"
-#include "impeller/entity/texture_fill_external.frag.h"
+#include "impeller/entity/texture_fill_strict_src.frag.h"
+#include "impeller/entity/tiled_texture_fill_external.frag.h"
 #include "impeller/geometry/constants.h"
 #include "impeller/renderer/render_pass.h"
 #include "impeller/renderer/vertex_buffer_builder.h"
@@ -113,8 +114,8 @@ bool TextureContents::Render(const ContentContext& renderer,
 
   using VS = TextureFillVertexShader;
   using FS = TextureFillFragmentShader;
-  using FSStrictSrc = TextureFillStrictSrcFragmentShader;
-  using FSExternal = TextureFillExternalFragmentShader;
+  using FSExternal = TiledTextureFillExternalFragmentShader;
+  using FSStrict = TextureFillStrictSrcFragmentShader;
 
   if (destination_rect_.IsEmpty() || source_rect_.IsEmpty() ||
       texture_ == nullptr || texture_->GetSize().IsEmpty()) {
@@ -129,7 +130,6 @@ bool TextureContents::Render(const ContentContext& renderer,
       Rect::MakeSize(texture_->GetSize()).Project(source_rect);
 
   VertexBufferBuilder<VS::PerVertexData> vertex_builder;
-
   auto destination_rect =
       capture.AddRect("Destination rect", destination_rect_);
   vertex_builder.AddVertices({
@@ -144,7 +144,6 @@ bool TextureContents::Render(const ContentContext& renderer,
   VS::FrameInfo frame_info;
   frame_info.mvp = entity.GetShaderTransform(pass);
   frame_info.texture_sampler_y_coord_scale = texture_->GetYCoordScale();
-  frame_info.alpha = capture.AddScalar("Alpha", GetOpacity());
 
 #ifdef IMPELLER_DEBUG
   if (label_.empty()) {
@@ -163,7 +162,7 @@ bool TextureContents::Render(const ContentContext& renderer,
   std::shared_ptr<Pipeline<PipelineDescriptor>> pipeline;
 #ifdef IMPELLER_ENABLE_OPENGLES
   if (is_external_texture) {
-    pipeline = renderer.GetTextureExternalPipeline(pipeline_options);
+    pipeline = renderer.GetTiledTextureExternalPipeline(pipeline_options);
   }
 #endif  // IMPELLER_ENABLE_OPENGLES
 
@@ -178,26 +177,46 @@ bool TextureContents::Render(const ContentContext& renderer,
 
   pass.SetVertexBuffer(vertex_builder.CreateVertexBuffer(host_buffer));
   VS::BindFrameInfo(pass, host_buffer.EmplaceUniform(frame_info));
+
   if (is_external_texture) {
+    FSExternal::FragInfo frag_info;
+    frag_info.x_tile_mode =
+        static_cast<int>(sampler_descriptor_.width_address_mode);
+    frag_info.y_tile_mode =
+        static_cast<int>(sampler_descriptor_.height_address_mode);
+    frag_info.alpha = capture.AddScalar("Alpha", GetOpacity());
+
+    auto sampler_descriptor = sampler_descriptor_;
+    // OES_EGL_image_external states that only CLAMP_TO_EDGE is valid, so
+    // we emulate all other tile modes here by remapping the texture
+    // coordinates.
+    sampler_descriptor.width_address_mode = SamplerAddressMode::kClampToEdge;
+    sampler_descriptor.height_address_mode = SamplerAddressMode::kClampToEdge;
+
+    FSExternal::BindFragInfo(pass, host_buffer.EmplaceUniform((frag_info)));
     FSExternal::BindSAMPLEREXTERNALOESTextureSampler(
         pass, texture_,
         renderer.GetContext()->GetSamplerLibrary()->GetSampler(
-            sampler_descriptor_));
+            sampler_descriptor));
   } else if (strict_source_rect_enabled_) {
     // For a strict source rect, shrink the texture coordinate range by half a
     // texel to ensure that linear filtering does not sample anything outside
     // the source rect bounds.
     auto strict_texture_coords =
         Rect::MakeSize(texture_->GetSize()).Project(source_rect.Expand(-0.5));
 
-    FSStrictSrc::FragInfo frag_info;
+    FSStrict::FragInfo frag_info;
     frag_info.source_rect = Vector4(strict_texture_coords.GetLTRB());
-    FSStrictSrc::BindFragInfo(pass, host_buffer.EmplaceUniform(frag_info));
-    FSStrictSrc::BindTextureSampler(
+    frag_info.alpha = capture.AddScalar("Alpha", GetOpacity());
+    FSStrict::BindFragInfo(pass, host_buffer.EmplaceUniform((frag_info)));
+    FSStrict::BindTextureSampler(
         pass, texture_,
         renderer.GetContext()->GetSamplerLibrary()->GetSampler(
             sampler_descriptor_));
   } else {
+    FS::FragInfo frag_info;
+    frag_info.alpha = capture.AddScalar("Alpha", GetOpacity());
+    FS::BindFragInfo(pass, host_buffer.EmplaceUniform((frag_info)));
     FS::BindTextureSampler(
         pass, texture_,
         renderer.GetContext()->GetSamplerLibrary()->GetSampler(

impeller/entity/contents/tiled_texture_contents.cc

@@ -6,6 +6,7 @@
 
 #include "fml/logging.h"
 #include "impeller/entity/contents/content_context.h"
+#include "impeller/entity/texture_fill.frag.h"
 #include "impeller/entity/texture_fill.vert.h"
 #include "impeller/entity/tiled_texture_fill.frag.h"
 #include "impeller/entity/tiled_texture_fill_external.frag.h"
@@ -132,7 +133,6 @@ bool TiledTextureContents::Render(const ContentContext& renderer,
 
   VS::FrameInfo frame_info;
   frame_info.texture_sampler_y_coord_scale = texture_->GetYCoordScale();
-  frame_info.alpha = GetOpacityFactor();
 
   PipelineBuilderMethod pipeline_method;
 
@@ -170,12 +170,19 @@ bool TiledTextureContents::Render(const ContentContext& renderer,
           FSExternal::FragInfo frag_info;
           frag_info.x_tile_mode = static_cast<Scalar>(x_tile_mode_);
           frag_info.y_tile_mode = static_cast<Scalar>(y_tile_mode_);
+          frag_info.alpha = GetOpacityFactor();
           FSExternal::BindFragInfo(pass, host_buffer.EmplaceUniform(frag_info));
         } else if (uses_emulated_tile_mode) {
           FS::FragInfo frag_info;
           frag_info.x_tile_mode = static_cast<Scalar>(x_tile_mode_);
           frag_info.y_tile_mode = static_cast<Scalar>(y_tile_mode_);
+          frag_info.alpha = GetOpacityFactor();
           FS::BindFragInfo(pass, host_buffer.EmplaceUniform(frag_info));
+        } else {
+          TextureFillFragmentShader::FragInfo frag_info;
+          frag_info.alpha = GetOpacityFactor();
+          TextureFillFragmentShader::BindFragInfo(
+              pass, host_buffer.EmplaceUniform(frag_info));
         }
 
         if (is_external_texture) {

impeller/entity/contents/vertices_contents.cc

@@ -169,9 +169,11 @@ bool VerticesUVContents::Render(const ContentContext& renderer,
   frame_info.mvp = geometry_result.transform;
   frame_info.texture_sampler_y_coord_scale =
       snapshot->texture->GetYCoordScale();
-  frame_info.alpha = alpha_ * snapshot->opacity;
   VS::BindFrameInfo(pass, host_buffer.EmplaceUniform(frame_info));
 
+  FS::FragInfo frag_info;
+  frag_info.alpha = alpha_ * snapshot->opacity;
+  FS::BindFragInfo(pass, host_buffer.EmplaceUniform(frag_info));
   FS::BindTextureSampler(pass, snapshot->texture,
                          renderer.GetContext()->GetSamplerLibrary()->GetSampler(
                              snapshot->sampler_descriptor));