[Impeller] Gaussian blur: Add alpha mask specialization

ci/licenses_golden/licenses_flutter

@@ -1246,10 +1246,12 @@ ORIGIN: ../../../flutter/impeller/entity/shaders/color_matrix_color_filter.frag
 ORIGIN: ../../../flutter/impeller/entity/shaders/color_matrix_color_filter.vert + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/conical_gradient_fill.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/conical_gradient_ssbo_fill.frag + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur.frag + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur.glsl + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur.vert + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur_decal.frag + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur.glsl + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur.vert + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha_decal.frag + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha_nodecal.frag + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_decal.frag + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_nodecal.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/glyph_atlas.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/glyph_atlas.vert + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/glyph_atlas_sdf.frag + ../../../flutter/LICENSE
@@ -3809,10 +3811,12 @@ FILE: ../../../flutter/impeller/entity/shaders/color_matrix_color_filter.frag
 FILE: ../../../flutter/impeller/entity/shaders/color_matrix_color_filter.vert
 FILE: ../../../flutter/impeller/entity/shaders/conical_gradient_fill.frag
 FILE: ../../../flutter/impeller/entity/shaders/conical_gradient_ssbo_fill.frag
-FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur.frag
-FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur.glsl
-FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur.vert
-FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur_decal.frag
+FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur.glsl
+FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur.vert
+FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha_decal.frag
+FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha_nodecal.frag
+FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_decal.frag
+FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_nodecal.frag
 FILE: ../../../flutter/impeller/entity/shaders/glyph_atlas.frag
 FILE: ../../../flutter/impeller/entity/shaders/glyph_atlas.vert
 FILE: ../../../flutter/impeller/entity/shaders/glyph_atlas_sdf.frag

impeller/entity/BUILD.gn

@@ -35,9 +35,11 @@ impeller_shaders("entity_shaders") {
     "shaders/color_matrix_color_filter.frag",
     "shaders/color_matrix_color_filter.vert",
     "shaders/conical_gradient_fill.frag",
-    "shaders/gaussian_blur.frag",
-    "shaders/gaussian_blur_decal.frag",
-    "shaders/gaussian_blur.vert",
+    "shaders/gaussian_blur/gaussian_blur.vert",
+    "shaders/gaussian_blur/gaussian_blur_alpha_decal.frag",
+    "shaders/gaussian_blur/gaussian_blur_alpha_nodecal.frag",
+    "shaders/gaussian_blur/gaussian_blur_noalpha_decal.frag",
+    "shaders/gaussian_blur/gaussian_blur_noalpha_nodecal.frag",
     "shaders/glyph_atlas.frag",
     "shaders/glyph_atlas.vert",
     "shaders/glyph_atlas_sdf.frag",

impeller/entity/contents/content_context.cc

@@ -261,10 +261,14 @@ ContentContext::ContentContext(std::shared_ptr<Context> context)
       CreateDefaultPipeline<PositionUVPipeline>(*context_);
   tiled_texture_pipelines_[{}] =
       CreateDefaultPipeline<TiledTexturePipeline>(*context_);
-  gaussian_blur_pipelines_[{}] =
-      CreateDefaultPipeline<GaussianBlurPipeline>(*context_);
-  gaussian_blur_decal_pipelines_[{}] =
+  gaussian_blur_alpha_decal_pipelines_[{}] =
+      CreateDefaultPipeline<GaussianBlurAlphaDecalPipeline>(*context_);
+  gaussian_blur_alpha_nodecal_pipelines_[{}] =
+      CreateDefaultPipeline<GaussianBlurAlphaPipeline>(*context_);
+  gaussian_blur_noalpha_decal_pipelines_[{}] =
       CreateDefaultPipeline<GaussianBlurDecalPipeline>(*context_);
+  gaussian_blur_noalpha_nodecal_pipelines_[{}] =
+      CreateDefaultPipeline<GaussianBlurPipeline>(*context_);
   border_mask_blur_pipelines_[{}] =
       CreateDefaultPipeline<BorderMaskBlurPipeline>(*context_);
   morphology_filter_pipelines_[{}] =

impeller/entity/contents/content_context.h

@@ -12,17 +12,19 @@
 #include "flutter/fml/logging.h"
 #include "flutter/fml/macros.h"
 #include "impeller/base/validation.h"
+#include "impeller/entity/entity.h"
+#include "impeller/renderer/capabilities.h"
+#include "impeller/renderer/formats.h"
+#include "impeller/renderer/pipeline.h"
+#include "impeller/scene/scene_context.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/color_matrix_color_filter.frag.h"
 #include "impeller/entity/color_matrix_color_filter.vert.h"
 #include "impeller/entity/conical_gradient_fill.frag.h"
-#include "impeller/entity/entity.h"
-#include "impeller/entity/gaussian_blur.frag.h"
-#include "impeller/entity/gaussian_blur.vert.h"
-#include "impeller/entity/gaussian_blur_decal.frag.h"
 #include "impeller/entity/glyph_atlas.frag.h"
 #include "impeller/entity/glyph_atlas.vert.h"
 #include "impeller/entity/glyph_atlas_sdf.frag.h"
@@ -48,10 +50,12 @@
 #include "impeller/entity/vertices.frag.h"
 #include "impeller/entity/yuv_to_rgb_filter.frag.h"
 #include "impeller/entity/yuv_to_rgb_filter.vert.h"
-#include "impeller/renderer/capabilities.h"
-#include "impeller/renderer/formats.h"
-#include "impeller/renderer/pipeline.h"
-#include "impeller/scene/scene_context.h"
+
+#include "impeller/entity/gaussian_blur.vert.h"
+#include "impeller/entity/gaussian_blur_alpha_decal.frag.h"
+#include "impeller/entity/gaussian_blur_alpha_nodecal.frag.h"
+#include "impeller/entity/gaussian_blur_noalpha_decal.frag.h"
+#include "impeller/entity/gaussian_blur_noalpha_nodecal.frag.h"
 
 #include "impeller/entity/position_color.vert.h"
 
@@ -132,10 +136,18 @@ using PositionUVPipeline =
     RenderPipelineT<TextureFillVertexShader, TiledTextureFillFragmentShader>;
 using TiledTexturePipeline = RenderPipelineT<TiledTextureFillVertexShader,
                                              TiledTextureFillFragmentShader>;
-using GaussianBlurPipeline =
-    RenderPipelineT<GaussianBlurVertexShader, GaussianBlurFragmentShader>;
+using GaussianBlurAlphaDecalPipeline =
+    RenderPipelineT<GaussianBlurVertexShader,
+                    GaussianBlurAlphaDecalFragmentShader>;
+using GaussianBlurAlphaPipeline =
+    RenderPipelineT<GaussianBlurVertexShader,
+                    GaussianBlurAlphaNodecalFragmentShader>;
 using GaussianBlurDecalPipeline =
-    RenderPipelineT<GaussianBlurVertexShader, GaussianBlurDecalFragmentShader>;
+    RenderPipelineT<GaussianBlurVertexShader,
+                    GaussianBlurNoalphaDecalFragmentShader>;
+using GaussianBlurPipeline =
+    RenderPipelineT<GaussianBlurVertexShader,
+                    GaussianBlurNoalphaNodecalFragmentShader>;
 using BorderMaskBlurPipeline =
     RenderPipelineT<BorderMaskBlurVertexShader, BorderMaskBlurFragmentShader>;
 using MorphologyFilterPipeline =
@@ -388,14 +400,24 @@ class ContentContext {
     return GetPipeline(tiled_texture_pipelines_, opts);
   }
 
-  std::shared_ptr<Pipeline<PipelineDescriptor>> GetGaussianBlurPipeline(
+  std::shared_ptr<Pipeline<PipelineDescriptor>>
+  GetGaussianBlurAlphaDecalPipeline(ContentContextOptions opts) const {
+    return GetPipeline(gaussian_blur_alpha_decal_pipelines_, opts);
+  }
+
+  std::shared_ptr<Pipeline<PipelineDescriptor>> GetGaussianBlurAlphaPipeline(
       ContentContextOptions opts) const {
-    return GetPipeline(gaussian_blur_pipelines_, opts);
+    return GetPipeline(gaussian_blur_alpha_nodecal_pipelines_, opts);
   }
 
   std::shared_ptr<Pipeline<PipelineDescriptor>> GetGaussianBlurDecalPipeline(
       ContentContextOptions opts) const {
-    return GetPipeline(gaussian_blur_decal_pipelines_, opts);
+    return GetPipeline(gaussian_blur_noalpha_decal_pipelines_, opts);
+  }
+
+  std::shared_ptr<Pipeline<PipelineDescriptor>> GetGaussianBlurPipeline(
+      ContentContextOptions opts) const {
+    return GetPipeline(gaussian_blur_noalpha_nodecal_pipelines_, opts);
   }
 
   std::shared_ptr<Pipeline<PipelineDescriptor>> GetBorderMaskBlurPipeline(
@@ -665,8 +687,14 @@ class ContentContext {
   mutable Variants<TexturePipeline> texture_pipelines_;
   mutable Variants<PositionUVPipeline> position_uv_pipelines_;
   mutable Variants<TiledTexturePipeline> tiled_texture_pipelines_;
-  mutable Variants<GaussianBlurPipeline> gaussian_blur_pipelines_;
-  mutable Variants<GaussianBlurDecalPipeline> gaussian_blur_decal_pipelines_;
+  mutable Variants<GaussianBlurAlphaDecalPipeline>
+      gaussian_blur_alpha_decal_pipelines_;
+  mutable Variants<GaussianBlurAlphaPipeline>
+      gaussian_blur_alpha_nodecal_pipelines_;
+  mutable Variants<GaussianBlurDecalPipeline>
+      gaussian_blur_noalpha_decal_pipelines_;
+  mutable Variants<GaussianBlurPipeline>
+      gaussian_blur_noalpha_nodecal_pipelines_;
   mutable Variants<BorderMaskBlurPipeline> border_mask_blur_pipelines_;
   mutable Variants<MorphologyFilterPipeline> morphology_filter_pipelines_;
   mutable Variants<ColorMatrixColorFilterPipeline>

impeller/entity/contents/filters/gaussian_blur_filter_contents.cc

@@ -87,8 +87,8 @@ std::optional<Entity> DirectionalGaussianBlurFilterContents::RenderFilter(
     const Entity& entity,
     const Matrix& effect_transform,
     const Rect& coverage) const {
-  using VS = GaussianBlurPipeline::VertexShader;
-  using FS = GaussianBlurPipeline::FragmentShader;
+  using VS = GaussianBlurAlphaDecalPipeline::VertexShader;
+  using FS = GaussianBlurAlphaDecalPipeline::FragmentShader;
 
   //----------------------------------------------------------------------------
   /// Handle inputs.
@@ -192,7 +192,7 @@ std::optional<Entity> DirectionalGaussianBlurFilterContents::RenderFilter(
     frame_info.alpha_mask_sampler_y_coord_scale =
         source_snapshot->texture->GetYCoordScale();
 
-    FS::FragInfo frag_info;
+    FS::BlurInfo frag_info;
     auto r = Radius{transformed_blur_radius_length};
     frag_info.blur_sigma = Sigma{r}.sigma;
     frag_info.blur_radius = r.radius;
@@ -201,9 +201,6 @@ std::optional<Entity> DirectionalGaussianBlurFilterContents::RenderFilter(
     frag_info.blur_direction =
         pass_transform.Invert().TransformDirection(Vector2(1, 0)).Normalize();
 
-    frag_info.src_factor = src_color_factor_;
-    frag_info.inner_blur_factor = inner_blur_factor_;
-    frag_info.outer_blur_factor = outer_blur_factor_;
     frag_info.texture_size = Point(input_snapshot->GetCoverage().value().size);
 
     Command cmd;
@@ -217,42 +214,60 @@ std::optional<Entity> DirectionalGaussianBlurFilterContents::RenderFilter(
     auto source_descriptor = source_snapshot->sampler_descriptor;
     switch (tile_mode_) {
       case Entity::TileMode::kDecal:
-        cmd.pipeline = renderer.GetGaussianBlurDecalPipeline(options);
         break;
       case Entity::TileMode::kClamp:
-        cmd.pipeline = renderer.GetGaussianBlurPipeline(options);
         input_descriptor.width_address_mode = SamplerAddressMode::kClampToEdge;
         input_descriptor.height_address_mode = SamplerAddressMode::kClampToEdge;
         source_descriptor.width_address_mode = SamplerAddressMode::kClampToEdge;
         source_descriptor.height_address_mode =
             SamplerAddressMode::kClampToEdge;
         break;
       case Entity::TileMode::kMirror:
-        cmd.pipeline = renderer.GetGaussianBlurPipeline(options);
         input_descriptor.width_address_mode = SamplerAddressMode::kMirror;
         input_descriptor.height_address_mode = SamplerAddressMode::kMirror;
         source_descriptor.width_address_mode = SamplerAddressMode::kMirror;
         source_descriptor.height_address_mode = SamplerAddressMode::kMirror;
         break;
       case Entity::TileMode::kRepeat:
-        cmd.pipeline = renderer.GetGaussianBlurPipeline(options);
         input_descriptor.width_address_mode = SamplerAddressMode::kRepeat;
         input_descriptor.height_address_mode = SamplerAddressMode::kRepeat;
         source_descriptor.width_address_mode = SamplerAddressMode::kRepeat;
         source_descriptor.height_address_mode = SamplerAddressMode::kRepeat;
         break;
     }
 
+    bool has_alpha_mask = blur_style_ != BlurStyle::kNormal;
+    bool has_decal_specialization = tile_mode_ == Entity::TileMode::kDecal;
+
+    if (has_alpha_mask && has_decal_specialization) {
+      cmd.pipeline = renderer.GetGaussianBlurAlphaDecalPipeline(options);
+    } else if (has_alpha_mask) {
+      cmd.pipeline = renderer.GetGaussianBlurAlphaPipeline(options);
+    } else if (has_decal_specialization) {
+      cmd.pipeline = renderer.GetGaussianBlurDecalPipeline(options);
+    } else {
+      cmd.pipeline = renderer.GetGaussianBlurPipeline(options);
+    }
+
     FS::BindTextureSampler(
         cmd, input_snapshot->texture,
         renderer.GetContext()->GetSamplerLibrary()->GetSampler(
             input_descriptor));
-    FS::BindAlphaMaskSampler(
-        cmd, source_snapshot->texture,
-        renderer.GetContext()->GetSamplerLibrary()->GetSampler(
-            source_descriptor));
     VS::BindFrameInfo(cmd, host_buffer.EmplaceUniform(frame_info));
-    FS::BindFragInfo(cmd, host_buffer.EmplaceUniform(frag_info));
+    FS::BindBlurInfo(cmd, host_buffer.EmplaceUniform(frag_info));
+
+    if (has_alpha_mask) {
+      FS::MaskInfo mask_info;
+      mask_info.src_factor = src_color_factor_;
+      mask_info.inner_blur_factor = inner_blur_factor_;
+      mask_info.outer_blur_factor = outer_blur_factor_;
+
+      FS::BindAlphaMaskSampler(
+          cmd, source_snapshot->texture,
+          renderer.GetContext()->GetSamplerLibrary()->GetSampler(
+              source_descriptor));
+      FS::BindMaskInfo(cmd, host_buffer.EmplaceUniform(mask_info));
+    }
 
     return pass.AddCommand(cmd);
   };

impeller/entity/shaders/gaussian_blur.glsl → impeller/entity/shaders/gaussian_blur/gaussian_blur.glsl

@@ -19,9 +19,8 @@
 #include <impeller/types.glsl>
 
 uniform sampler2D texture_sampler;
-uniform sampler2D alpha_mask_sampler;
 
-uniform FragInfo {
+uniform BlurInfo {
   vec2 texture_size;
   vec2 blur_direction;
 
@@ -31,12 +30,27 @@ uniform FragInfo {
   // radius is used to limit how much of the function is integrated.
   float blur_sigma;
   float blur_radius;
+}
+blur_info;
+
+#if ENABLE_ALPHA_MASK
+uniform sampler2D alpha_mask_sampler;
 
+uniform MaskInfo {
   float src_factor;
   float inner_blur_factor;
   float outer_blur_factor;
 }
-frag_info;
+mask_info;
+#endif
+
+vec4 Sample(sampler2D tex, vec2 coords) {
+#if ENABLE_DECAL_SPECIALIZATION
+  return IPSampleDecal(tex, coords);
+#else
+  return texture(tex, coords);
+#endif
+}
 
 in vec2 v_texture_coords;
 in vec2 v_src_texture_coords;
@@ -46,10 +60,10 @@ out vec4 frag_color;
 void main() {
   vec4 total_color = vec4(0);
   float gaussian_integral = 0;
-  vec2 blur_uv_offset = frag_info.blur_direction / frag_info.texture_size;
+  vec2 blur_uv_offset = blur_info.blur_direction / blur_info.texture_size;
 
-  for (float i = -frag_info.blur_radius; i <= frag_info.blur_radius; i++) {
-    float gaussian = IPGaussian(i, frag_info.blur_sigma);
+  for (float i = -blur_info.blur_radius; i <= blur_info.blur_radius; i++) {
+    float gaussian = IPGaussian(i, blur_info.blur_sigma);
     gaussian_integral += gaussian;
     total_color +=
         gaussian *
@@ -58,13 +72,15 @@ void main() {
         );
   }
 
-  vec4 blur_color = total_color / gaussian_integral;
+  frag_color = total_color / gaussian_integral;
 
+#if ENABLE_ALPHA_MASK
   vec4 src_color = Sample(alpha_mask_sampler,   // sampler
                           v_src_texture_coords  // texture coordinates
   );
-  float blur_factor = frag_info.inner_blur_factor * float(src_color.a > 0) +
-                      frag_info.outer_blur_factor * float(src_color.a == 0);
+  float blur_factor = mask_info.inner_blur_factor * float(src_color.a > 0) +
+                      mask_info.outer_blur_factor * float(src_color.a == 0);
 
-  frag_color = blur_color * blur_factor + src_color * frag_info.src_factor;
+  frag_color = frag_color * blur_factor + src_color * mask_info.src_factor;
+#endif
 }

impeller/entity/shaders/gaussian_blur.frag → impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha_decal.frag

@@ -2,10 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include <impeller/texture.glsl>
-
-vec4 Sample(sampler2D tex, vec2 coords) {
-  return texture(tex, coords);
-}
+#define ENABLE_ALPHA_MASK 1
+#define ENABLE_DECAL_SPECIALIZATION 1
 
 #include "gaussian_blur.glsl"

impeller/entity/shaders/gaussian_blur_decal.frag → impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha_nodecal.frag

@@ -2,10 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include <impeller/texture.glsl>
-
-vec4 Sample(sampler2D tex, vec2 coords) {
-  return IPSampleDecal(tex, coords);
-}
+#define ENABLE_ALPHA_MASK 1
+#define ENABLE_DECAL_SPECIALIZATION 0
 
 #include "gaussian_blur.glsl"

impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_decal.frag

@@ -0,0 +1,8 @@
+// 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.
+
+#define ENABLE_ALPHA_MASK 0
+#define ENABLE_DECAL_SPECIALIZATION 1
+
+#include "gaussian_blur.glsl"

impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_nodecal.frag

@@ -0,0 +1,8 @@
+// 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.
+
+#define ENABLE_ALPHA_MASK 0
+#define ENABLE_DECAL_SPECIALIZATION 0
+
+#include "gaussian_blur.glsl"