added new kernel shader

impeller/entity/BUILD.gn

@@ -28,6 +28,8 @@ impeller_shaders("entity_shaders") {
     "shaders/gaussian_blur/gaussian_blur.vert",
     "shaders/gaussian_blur/gaussian_blur_noalpha_decal.frag",
     "shaders/gaussian_blur/gaussian_blur_noalpha_nodecal.frag",
+    "shaders/gaussian_blur/kernel_decal.frag",
+    "shaders/gaussian_blur/kernel_nodecal.frag",
     "shaders/glyph_atlas.frag",
     "shaders/glyph_atlas_color.frag",
     "shaders/glyph_atlas.vert",

impeller/entity/contents/content_context.h

@@ -67,6 +67,8 @@
 #include "impeller/entity/gaussian_blur.vert.h"
 #include "impeller/entity/gaussian_blur_noalpha_decal.frag.h"
 #include "impeller/entity/gaussian_blur_noalpha_nodecal.frag.h"
+#include "impeller/entity/kernel_decal.frag.h"
+#include "impeller/entity/kernel_nodecal.frag.h"
 
 #include "impeller/entity/position_color.vert.h"
 
@@ -137,6 +139,12 @@ using GaussianBlurDecalPipeline =
 using GaussianBlurPipeline =
     RenderPipelineT<GaussianBlurVertexShader,
                     GaussianBlurNoalphaNodecalFragmentShader>;
+using KernelDecalPipeline =
+    RenderPipelineT<GaussianBlurVertexShader,
+                    KernelDecalFragmentShader>;
+using KernelPipeline =
+    RenderPipelineT<GaussianBlurVertexShader,
+                    KernelNodecalFragmentShader>;
 using BorderMaskBlurPipeline =
     RenderPipelineT<BorderMaskBlurVertexShader, BorderMaskBlurFragmentShader>;
 using MorphologyFilterPipeline =

impeller/entity/contents/filters/directional_gaussian_blur_filter_contents.cc

@@ -77,8 +77,8 @@ std::optional<Entity> DirectionalGaussianBlurFilterContents::RenderFilter(
     const Matrix& effect_transform,
     const Rect& coverage,
     const std::optional<Rect>& coverage_hint) const {
-  using VS = GaussianBlurPipeline::VertexShader;
-  using FS = GaussianBlurPipeline::FragmentShader;
+  using VS = KernelPipeline::VertexShader;
+  using FS = KernelPipeline::FragmentShader;
 
   //----------------------------------------------------------------------------
   /// Handle inputs.

impeller/entity/contents/filters/gaussian_blur_filter_contents.cc

@@ -14,8 +14,8 @@
 
 namespace impeller {
 
-using GaussianBlurVertexShader = GaussianBlurPipeline::VertexShader;
-using GaussianBlurFragmentShader = GaussianBlurPipeline::FragmentShader;
+using GaussianBlurVertexShader = KernelPipeline::VertexShader;
+using GaussianBlurFragmentShader = KernelPipeline::FragmentShader;
 
 namespace {
 
@@ -431,9 +431,9 @@ Scalar GaussianBlurFilterContents::ScaleSigma(Scalar sigma) {
   return clamped * scalar;
 }
 
-GaussianBlurPipeline::FragmentShader::KernelSamples GenerateBlurInfo(
+KernelPipeline::FragmentShader::KernelSamples GenerateBlurInfo(
     BlurParameters parameters) {
-  GaussianBlurPipeline::FragmentShader::KernelSamples result{
+  KernelPipeline::FragmentShader::KernelSamples result{
       .sample_count =
           ((2 * parameters.blur_radius) / parameters.step_size) + 1};
   FML_CHECK(result.sample_count < 24);

impeller/entity/contents/filters/gaussian_blur_filter_contents.h

@@ -18,7 +18,7 @@ struct BlurParameters {
   int step_size;
 };
 
-GaussianBlurPipeline::FragmentShader::KernelSamples GenerateBlurInfo(
+KernelPipeline::FragmentShader::KernelSamples GenerateBlurInfo(
     BlurParameters parameters);
 
 /// Performs a bidirectional Gaussian blur.

impeller/entity/shaders/gaussian_blur/kernel.glsl

@@ -0,0 +1,46 @@
+// 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 <impeller/constants.glsl>
+#include <impeller/gaussian.glsl>
+#include <impeller/texture.glsl>
+#include <impeller/types.glsl>
+
+uniform f16sampler2D texture_sampler;
+
+struct KernelSample {
+  f16vec2 uv_offset;
+  float16_t coefficient;
+};
+
+uniform KernelSamples {
+  int sample_count;
+  KernelSample samples[24];
+}
+blur_info;
+
+f16vec4 Sample(f16sampler2D tex, vec2 coords) {
+#if ENABLE_DECAL_SPECIALIZATION
+  return IPHalfSampleDecal(tex, coords);
+#else
+  return texture(tex, coords);
+#endif
+}
+
+in vec2 v_texture_coords;
+
+out f16vec4 frag_color;
+
+void main() {
+  f16vec4 total_color = f16vec4(0.0hf);
+
+  for (int i = 0; i < blur_info.sample_count; ++i) {
+    float16_t coefficient = blur_info.samples[i].coefficient;
+    total_color +=
+        coefficient * Sample(texture_sampler,
+                             v_texture_coords + blur_info.samples[i].uv_offset);
+  }
+
+  frag_color = total_color;
+}

impeller/entity/shaders/gaussian_blur/kernel_decal.frag

@@ -0,0 +1,9 @@
+// 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.
+
+precision mediump float;
+
+#define ENABLE_DECAL_SPECIALIZATION 1
+
+#include "kernel.glsl"

impeller/entity/shaders/gaussian_blur/kernel_nodecal.frag

@@ -0,0 +1,9 @@
+// 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.
+
+precision mediump float;
+
+#define ENABLE_DECAL_SPECIALIZATION 0
+
+#include "kernel.glsl"