commit a12c15376ce3f94c81f461120067f8bbcf0a0c69
author Brian Salomon <bsalomon@google.com> Mon Feb 13 12:41:44 2017 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Mon Feb 13 18:14:12 2017 +0000
tree 3d77a9d562b9b764aa15c40bed9a2ded7584a6af
parent 1fd1823b4775040b6a9723db90029d037c34ea54

Add preserves premul and modulate optimization to compose fragment processors.

Fixes out of range colors produced by matrix convolution and dither effects. Adds modulate optimization to matrix convolution.

Change-Id: I8424250a52e864f4b5feaf4474293695c26039d8
Reviewed-on: https://skia-review.googlesource.com/8351
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>

src/gpu/effects/GrMatrixConvolutionEffect.cpp

diff --git a/src/gpu/effects/GrMatrixConvolutionEffect.cpp b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
index 1a40514..fc8add8 100644
--- a/src/gpu/effects/GrMatrixConvolutionEffect.cpp
+++ b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
@@ -98,6 +98,7 @@
     }
     if (mce.convolveAlpha()) {
         fragBuilder->codeAppendf("%s = sum * %s + %s;", args.fOutputColor, gain, bias);
+        fragBuilder->codeAppendf("%s.a = clamp(%s.a, 0, 1);", args.fOutputColor, args.fOutputColor);
         fragBuilder->codeAppendf("%s.rgb = clamp(%s.rgb, 0.0, %s.a);",
                                  args.fOutputColor, args.fOutputColor, args.fOutputColor);
     } else {
@@ -109,7 +110,7 @@
                               coords2D,
                               args.fTexSamplers[0]);
         fragBuilder->codeAppendf("%s.a = c.a;", args.fOutputColor);
-        fragBuilder->codeAppendf("%s.rgb = sum.rgb * %s + %s;", args.fOutputColor, gain, bias);
+        fragBuilder->codeAppendf("%s.rgb = clamp(sum.rgb * %s + %s, 0, 1);", args.fOutputColor, gain, bias);
         fragBuilder->codeAppendf("%s.rgb *= %s.a;", args.fOutputColor, args.fOutputColor);
     }
 
@@ -157,9 +158,8 @@
                                                      const SkIPoint& kernelOffset,
                                                      GrTextureDomain::Mode tileMode,
                                                      bool convolveAlpha)
-        // To advertise either the modulation or opaqueness optimizations we'd have to examine the
-        // parameters.
-        : INHERITED(texture, nullptr, SkMatrix::I(), kNone_OptimizationFlags)
+        // To advertise the preserves opaqueness optimization we'd have to examine the parameters.
+        : INHERITED(texture, nullptr, SkMatrix::I(), kModulatesInput_OptimizationFlag)
         , fKernelSize(kernelSize)
         , fGain(SkScalarToFloat(gain))
         , fBias(SkScalarToFloat(bias) / 255.0f)