[Impeller] Premultiply gradient alpha after the gradient LUT is gener…

…ated (flutter#36064)
vrana · Sep 10, 2022 · 0b6dcd8 · 0b6dcd8
1 parent dae737f
commit 0b6dcd8
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Showing 5 changed files with 5 additions and 2 deletions.
diff --git a/impeller/aiks/aiks_unittests.cc b/impeller/aiks/aiks_unittests.cc
@@ -336,7 +336,7 @@ TEST_P(AiksTest, CanRenderLinearGradient) {
  auto tile_mode = tile_modes[selected_tile_mode];
  paint.color_source = [tile_mode]() {
  std::vector<Color> colors = {Color{0.9568, 0.2627, 0.2118, 1.0},
- Color{0.1294, 0.5882, 0.9529, 1.0}};
+ Color{0.1294, 0.5882, 0.9529, 0.0}};
  std::vector<Scalar> stops = {0.0, 1.0};
 
  auto contents = std::make_shared<LinearGradientContents>();

diff --git a/impeller/entity/shaders/linear_gradient_fill.frag b/impeller/entity/shaders/linear_gradient_fill.frag
@@ -30,4 +30,5 @@ void main() {
  gradient_info.texture_sampler_y_coord_scale,
  gradient_info.tile_mode,
  gradient_info.tile_mode);
+ frag_color = vec4(frag_color.xyz * frag_color.a, frag_color.a);
 }
diff --git a/impeller/entity/shaders/radial_gradient_fill.frag b/impeller/entity/shaders/radial_gradient_fill.frag
@@ -26,4 +26,5 @@ void main() {
  gradient_info.texture_sampler_y_coord_scale,
  gradient_info.tile_mode,
  gradient_info.tile_mode);
+ frag_color = vec4(frag_color.xyz * frag_color.a, frag_color.a);
 }
diff --git a/impeller/entity/shaders/sweep_gradient_fill.frag b/impeller/entity/shaders/sweep_gradient_fill.frag
@@ -30,4 +30,5 @@ void main() {
  gradient_info.texture_sampler_y_coord_scale,
  gradient_info.tile_mode,
  gradient_info.tile_mode);
+ frag_color = vec4(frag_color.xyz * frag_color.a, frag_color.a);
 }
diff --git a/impeller/geometry/gradient.cc b/impeller/geometry/gradient.cc
@@ -9,7 +9,7 @@
 namespace impeller {
 
 static void AppendColor(const Color& color, std::vector<uint8_t>* colors) {
- auto converted = color.Premultiply().ToR8G8B8A8();
+ auto converted = color.ToR8G8B8A8();
  colors->push_back(converted[0]);
  colors->push_back(converted[1]);
  colors->push_back(converted[2]);