Two changes:
1. Remove special premul handling from gamut xform code
Alpha is a constant, so the gamut transformation results remain unchanged
(it distributes across the linear matrix multiply).
2. Use SkMatrix44 rather than array of floats
Preserves semantic intention, and makes upcoming code (where we transform
colors on the CPU by that matrix) simpler.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2329553002
Review-Url: https://codereview.chromium.org/2329553002
diff --git a/src/gpu/glsl/GrGLSLShaderBuilder.cpp b/src/gpu/glsl/GrGLSLShaderBuilder.cpp
index 26a7761..6d77bdb 100644
--- a/src/gpu/glsl/GrGLSLShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLShaderBuilder.cpp
@@ -133,27 +133,14 @@
GrGLSLColorSpaceXformHelper* colorXformHelper) {
// Our color is (r, g, b, a), but we want to multiply (r, g, b, 1) by our matrix, then
// re-insert the original alpha. The supplied srcColor is likely to be of the form
- // "texture(...)", and we don't want to evaluate that twice.
- //
- // Worse: We can't do the transformation on premultiplied colors, so if the source is premul,
- // we need to unpremul, transform, then multiply again. Anyways, we wrap all of the work in a
- // function.
+ // "texture(...)", and we don't want to evaluate that twice, so wrap everything in a function.
static const GrGLSLShaderVar gColorGamutXformArgs[] = {
GrGLSLShaderVar("color", kVec4f_GrSLType),
GrGLSLShaderVar("xform", kMat44f_GrSLType),
};
SkString functionBody;
- if (kPremul_SkAlphaType == colorXformHelper->alphaType()) {
- // Unpremultiply
- functionBody.append("\tfloat nonZeroAlpha = max(color.a, 0.00001);\n"
- "\tcolor.rgb = color.rgb / nonZeroAlpha;\n");
- }
// Gamut xform, clamp to destination gamut
functionBody.append("\tcolor.rgb = clamp((xform * vec4(color.rgb, 1.0)).rgb, 0.0, 1.0);\n");
- if (kPremul_SkAlphaType == colorXformHelper->alphaType()) {
- // Re-multiply by alpha
- functionBody.append("\tcolor.rgb = color.rgb * nonZeroAlpha;\n");
- }
functionBody.append("\treturn color;");
SkString colorGamutXformFuncName;
this->emitFunction(kVec4f_GrSLType,