Add colorburn blend mode

Author: bdero

impeller/aiks/aiks_unittests.cc

@@ -493,6 +493,7 @@ TEST_P(AiksTest, CanDrawWithAdvancedBlend) {
         {"Modulate", Entity::BlendMode::kModulate},
         // Advanced blends (non Porter-Duff/color blends)
         {"Screen", Entity::BlendMode::kScreen},
+        {"ColorBurn", Entity::BlendMode::kColorBurn},
     };
     assert(blends.size() ==
            static_cast<size_t>(Entity::BlendMode::kLastAdvancedBlendMode) + 1);

impeller/blobcat/blob.h

@@ -26,7 +26,7 @@ struct Blob {
     kFragment,
   };
 
-  static constexpr size_t kMaxNameLength = 24u;
+  static constexpr size_t kMaxNameLength = 32u;
 
   ShaderType type = ShaderType::kVertex;
   uint64_t offset = 0;

impeller/display_list/display_list_dispatcher.cc

@@ -213,11 +213,13 @@ static std::optional<Entity::BlendMode> ToBlendMode(flutter::DlBlendMode mode) {
     case flutter::DlBlendMode::kModulate:
       return Entity::BlendMode::kModulate;
     case flutter::DlBlendMode::kScreen:
+      return Entity::BlendMode::kScreen;
+    case flutter::DlBlendMode::kColorBurn:
+      return Entity::BlendMode::kColorBurn;
     case flutter::DlBlendMode::kOverlay:
     case flutter::DlBlendMode::kDarken:
     case flutter::DlBlendMode::kLighten:
     case flutter::DlBlendMode::kColorDodge:
-    case flutter::DlBlendMode::kColorBurn:
     case flutter::DlBlendMode::kHardLight:
     case flutter::DlBlendMode::kSoftLight:
     case flutter::DlBlendMode::kDifference:
@@ -239,6 +241,7 @@ void DisplayListDispatcher::setBlendMode(flutter::DlBlendMode dl_mode) {
     paint_.blend_mode = mode.value();
   } else {
     UNIMPLEMENTED;
+    paint_.blend_mode = Entity::BlendMode::kSourceOver;
   }
 }
 

impeller/entity/BUILD.gn

@@ -14,10 +14,11 @@ impeller_shaders("entity_shaders") {
     "shaders/solid_fill.vert",
     "shaders/solid_stroke.frag",
     "shaders/solid_stroke.vert",
-    "shaders/texture_blend.frag",
-    "shaders/texture_blend.vert",
-    "shaders/texture_blend_screen.frag",
-    "shaders/texture_blend_screen.vert",
+    "shaders/blend.frag",
+    "shaders/blend.vert",
+    "shaders/advanced_blend.vert",
+    "shaders/advanced_blend_screen.frag",
+    "shaders/advanced_blend_colorburn.frag",
     "shaders/gaussian_blur.frag",
     "shaders/gaussian_blur.vert",
     "shaders/border_mask_blur.frag",

impeller/entity/contents/content_context.cc

@@ -23,10 +23,11 @@ ContentContext::ContentContext(std::shared_ptr<Context> context)
   gradient_fill_pipelines_[{}] =
       std::make_unique<GradientFillPipeline>(*context_);
   solid_fill_pipelines_[{}] = std::make_unique<SolidFillPipeline>(*context_);
-  texture_blend_pipelines_[{}] =
-      std::make_unique<TextureBlendPipeline>(*context_);
-  texture_blend_screen_pipelines_[{}] =
-      std::make_unique<TextureBlendScreenPipeline>(*context_);
+  texture_blend_pipelines_[{}] = std::make_unique<BlendPipeline>(*context_);
+  blend_screen_pipelines_[{}] =
+      std::make_unique<BlendScreenPipeline>(*context_);
+  blend_colorburn_pipelines_[{}] =
+      std::make_unique<BlendColorburnPipeline>(*context_);
   texture_pipelines_[{}] = std::make_unique<TexturePipeline>(*context_);
   gaussian_blur_pipelines_[{}] =
       std::make_unique<GaussianBlurPipeline>(*context_);

impeller/entity/contents/content_context.h

@@ -11,6 +11,11 @@
 #include "flutter/fml/macros.h"
 #include "fml/logging.h"
 #include "impeller/base/validation.h"
+#include "impeller/entity/advanced_blend.vert.h"
+#include "impeller/entity/advanced_blend_colorburn.frag.h"
+#include "impeller/entity/advanced_blend_screen.frag.h"
+#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/entity.h"
@@ -24,10 +29,6 @@
 #include "impeller/entity/solid_fill.vert.h"
 #include "impeller/entity/solid_stroke.frag.h"
 #include "impeller/entity/solid_stroke.vert.h"
-#include "impeller/entity/texture_blend.frag.h"
-#include "impeller/entity/texture_blend.vert.h"
-#include "impeller/entity/texture_blend_screen.frag.h"
-#include "impeller/entity/texture_blend_screen.vert.h"
 #include "impeller/entity/texture_fill.frag.h"
 #include "impeller/entity/texture_fill.vert.h"
 #include "impeller/renderer/formats.h"
@@ -38,10 +39,11 @@ using GradientFillPipeline =
     PipelineT<GradientFillVertexShader, GradientFillFragmentShader>;
 using SolidFillPipeline =
     PipelineT<SolidFillVertexShader, SolidFillFragmentShader>;
-using TextureBlendPipeline =
-    PipelineT<TextureBlendVertexShader, TextureBlendFragmentShader>;
-using TextureBlendScreenPipeline =
-    PipelineT<TextureBlendScreenVertexShader, TextureBlendScreenFragmentShader>;
+using BlendPipeline = PipelineT<BlendVertexShader, BlendFragmentShader>;
+using BlendScreenPipeline =
+    PipelineT<AdvancedBlendVertexShader, AdvancedBlendScreenFragmentShader>;
+using BlendColorburnPipeline =
+    PipelineT<AdvancedBlendVertexShader, AdvancedBlendColorburnFragmentShader>;
 using TexturePipeline =
     PipelineT<TextureFillVertexShader, TextureFillFragmentShader>;
 using GaussianBlurPipeline =
@@ -98,14 +100,18 @@ class ContentContext {
     return GetPipeline(solid_fill_pipelines_, opts);
   }
 
-  std::shared_ptr<Pipeline> GetTextureBlendPipeline(
-      ContentContextOptions opts) const {
+  std::shared_ptr<Pipeline> GetBlendPipeline(ContentContextOptions opts) const {
     return GetPipeline(texture_blend_pipelines_, opts);
   }
 
-  std::shared_ptr<Pipeline> GetTextureBlendScreenPipeline(
+  std::shared_ptr<Pipeline> GetBlendScreenPipeline(
+      ContentContextOptions opts) const {
+    return GetPipeline(blend_screen_pipelines_, opts);
+  }
+
+  std::shared_ptr<Pipeline> GetBlendColorburnPipeline(
       ContentContextOptions opts) const {
-    return GetPipeline(texture_blend_screen_pipelines_, opts);
+    return GetPipeline(blend_colorburn_pipelines_, opts);
   }
 
   std::shared_ptr<Pipeline> GetTexturePipeline(
@@ -161,8 +167,9 @@ class ContentContext {
   // map.
   mutable Variants<GradientFillPipeline> gradient_fill_pipelines_;
   mutable Variants<SolidFillPipeline> solid_fill_pipelines_;
-  mutable Variants<TextureBlendPipeline> texture_blend_pipelines_;
-  mutable Variants<TextureBlendScreenPipeline> texture_blend_screen_pipelines_;
+  mutable Variants<BlendPipeline> texture_blend_pipelines_;
+  mutable Variants<BlendScreenPipeline> blend_screen_pipelines_;
+  mutable Variants<BlendColorburnPipeline> blend_colorburn_pipelines_;
   mutable Variants<TexturePipeline> texture_pipelines_;
   mutable Variants<GaussianBlurPipeline> gaussian_blur_pipelines_;
   mutable Variants<BorderMaskBlurPipeline> border_mask_blur_pipelines_;

impeller/entity/contents/filters/blend_filter_contents.cc

@@ -99,17 +99,28 @@ void BlendFilterContents::SetBlendMode(Entity::BlendMode blend_mode) {
 
   if (blend_mode > Entity::BlendMode::kLastPipelineBlendMode) {
     static_assert(Entity::BlendMode::kLastAdvancedBlendMode ==
-                  Entity::BlendMode::kScreen);
+                  Entity::BlendMode::kColorBurn);
 
     switch (blend_mode) {
       case Entity::BlendMode::kScreen:
         advanced_blend_proc_ = [](const FilterInput::Vector& inputs,
                                   const ContentContext& renderer,
                                   const Entity& entity, RenderPass& pass,
                                   const Rect& coverage) {
-          PipelineProc p = &ContentContext::GetTextureBlendScreenPipeline;
-          return AdvancedBlend<TextureBlendScreenPipeline::VertexShader,
-                               TextureBlendScreenPipeline::FragmentShader>(
+          PipelineProc p = &ContentContext::GetBlendScreenPipeline;
+          return AdvancedBlend<BlendScreenPipeline::VertexShader,
+                               BlendScreenPipeline::FragmentShader>(
+              inputs, renderer, entity, pass, coverage, p);
+        };
+        break;
+      case Entity::BlendMode::kColorBurn:
+        advanced_blend_proc_ = [](const FilterInput::Vector& inputs,
+                                  const ContentContext& renderer,
+                                  const Entity& entity, RenderPass& pass,
+                                  const Rect& coverage) {
+          PipelineProc p = &ContentContext::GetBlendColorburnPipeline;
+          return AdvancedBlend<BlendColorburnPipeline::VertexShader,
+                               BlendColorburnPipeline::FragmentShader>(
               inputs, renderer, entity, pass, coverage, p);
         };
         break;
@@ -125,8 +136,8 @@ static bool BasicBlend(const FilterInput::Vector& inputs,
                        RenderPass& pass,
                        const Rect& coverage,
                        Entity::BlendMode basic_blend) {
-  using VS = TextureBlendPipeline::VertexShader;
-  using FS = TextureBlendPipeline::FragmentShader;
+  using VS = BlendPipeline::VertexShader;
+  using FS = BlendPipeline::FragmentShader;
 
   auto& host_buffer = pass.GetTransientsBuffer();
 
@@ -175,7 +186,7 @@ static bool BasicBlend(const FilterInput::Vector& inputs,
   // Draw the first texture using kSource.
 
   options.blend_mode = Entity::BlendMode::kSource;
-  cmd.pipeline = renderer.GetTextureBlendPipeline(options);
+  cmd.pipeline = renderer.GetBlendPipeline(options);
   if (!add_blend_command(inputs[0]->GetSnapshot(renderer, entity))) {
     return true;
   }
@@ -187,7 +198,7 @@ static bool BasicBlend(const FilterInput::Vector& inputs,
   // Write subsequent textures using the selected blend mode.
 
   options.blend_mode = basic_blend;
-  cmd.pipeline = renderer.GetTextureBlendPipeline(options);
+  cmd.pipeline = renderer.GetBlendPipeline(options);
 
   for (auto texture_i = inputs.begin() + 1; texture_i < inputs.end();
        texture_i++) {

impeller/entity/entity.h

@@ -43,9 +43,10 @@ class Entity {
     // pipelines on most graphics devices without extensions, and so they are
     // only able to be used via `BlendFilterContents`.
     kScreen,
+    kColorBurn,
 
     kLastPipelineBlendMode = kModulate,
-    kLastAdvancedBlendMode = kScreen,
+    kLastAdvancedBlendMode = kColorBurn,
   };
 
   enum class ClipOperation {

impeller/entity/shaders/texture_blend_screen.vert renamed to impeller/entity/shaders/advanced_blend.vert

@@ -0,0 +1,30 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "blending.glsl"
+
+uniform sampler2D texture_sampler_dst;
+uniform sampler2D texture_sampler_src;
+
+in vec2 v_dst_texture_coords;
+in vec2 v_src_texture_coords;
+
+out vec4 frag_color;
+
+vec3 ComponentIsValue(vec3 n, float value) {
+  return vec3(n.r == value, n.g == value, n.b == value);
+}
+
+void main() {
+  const vec4 dst =
+      SampleWithBorder(texture_sampler_dst, v_dst_texture_coords);
+  const vec4 src =
+      SampleWithBorder(texture_sampler_src, v_src_texture_coords);
+
+  vec3 color = 1 - min(vec3(1), (1 - dst.rgb) / src.rgb);
+  color = mix(color, vec3(1), ComponentIsValue(dst.rgb, 1.0));
+  color = mix(color, vec3(0), ComponentIsValue(src.rgb, 0.0));
+
+  frag_color = vec4(color, dst.a - src.a + src.a);
+}