Potentially optimize some GrGLEffects for known input color values

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 380 matching lines @@
 
         GLEffect(const GrBackendEffectFactory& factory,
                  const GrDrawEffect&)
         : INHERITED(factory) {
         }
 
         virtual void emitCode(GrGLShaderBuilder* builder,
                               const GrDrawEffect&,
                               EffectKey,
                               const char* outputColor,
-                              const char* inputColor,
+                              const GrGLSLExpr4& inputColor,
                               const TransformedCoordsArray&,
                               const TextureSamplerArray&) SK_OVERRIDE {
             fMatrixHandle = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
                                                 kMat44f_GrSLType,
                                                 "ColorMatrix");
             fVectorHandle = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
                                                 kVec4f_GrSLType,
                                                 "ColorMatrixVector");
 
-            if (NULL == inputColor) {
-                // could optimize this case, but we aren't for now.
-                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("\tfloat nonZeroAlpha = %s;\n", GrGLSL::max(inputColor.a(), 0.00001f).c_str());
             builder->fsCodeAppendf("\t%s = %s * vec4(%s.rgb / nonZeroAlpha, nonZeroAlpha) + %s;\n",
                                    outputColor,
                                    builder->getUniformCStr(fMatrixHandle),
-                                   inputColor,
+                                   inputColor.c_str(),
                                    builder->getUniformCStr(fVectorHandle));
             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[]  = {
@@ skipping 54 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