Colormatrix GPU fix with saturated alpha.

src/effects/SkColorMatrixFilter.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkColorMatrixFilter.h"
 #include "SkColorMatrix.h"
 #include "SkColorPriv.h"
@@ skipping 406 matching lines @@
                 inputColor = "vec4(1)";
             }
             // The max() is to guard against 0 / 0 during unpremul when the incoming color is
             // transparent black.
             builder->fsCodeAppendf("\tfloat nonZeroAlpha = max(%s.a, 0.00001);\n", inputColor);
             builder->fsCodeAppendf("\t%s = %s * vec4(%s.rgb / nonZeroAlpha, nonZeroAlpha) + %s;\n",
                                    outputColor,
                                    builder->getUniformCStr(fMatrixHandle),
                                    inputColor,
                                    builder->getUniformCStr(fVectorHandle));
+            builder->fsCodeAppendf("\t%s = clamp(%s, 0.0, 1.0);\n", outputColor, outputColor);
             builder->fsCodeAppendf("\t%s.rgb *= %s.a;\n", outputColor, outputColor);
         }
 
         virtual void setData(const GrGLUniformManager& uniManager,
                              const GrDrawEffect& drawEffect) SK_OVERRIDE {
             const ColorMatrixEffect& cme = drawEffect.castEffect<ColorMatrixEffect>();
             const float* m = cme.fMatrix.fMat;
             // The GL matrix is transposed from SkColorMatrix.
             GrGLfloat mt[]  = {
                 m[0], m[5], m[10], m[15],
@@ skipping 53 matching lines @@
     str->append("matrix: (");
     for (int i = 0; i < 20; ++i) {
         str->appendScalar(fMatrix.fMat[i]);
         if (i < 19) {
             str->append(", ");
         }
     }
     str->append(")");
 }
 #endif