Implement color filter as GrGLEffect

src/gpu/gl/GrGLProgramDesc.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLProgramDesc.h"
 #include "GrBackendEffectFactory.h"
 #include "GrDrawEffect.h"
@@ skipping 52 matching lines @@
     // to a canonical value to avoid duplicate programs with different keys.
 
     bool requiresColorAttrib = !skipColor && drawState.hasColorVertexAttribute();
     bool requiresCoverageAttrib = !skipCoverage && drawState.hasCoverageVertexAttribute();
     // we only need the local coords if we're actually going to generate effect code
     bool requiresLocalCoordAttrib = !(skipCoverage  && skipColor) &&
                                     drawState.hasLocalCoordAttribute();
 
     bool colorIsTransBlack = SkToBool(blendOpts & GrDrawState::kEmitTransBlack_BlendOptFlag);
     bool colorIsSolidWhite = (blendOpts & GrDrawState::kEmitCoverage_BlendOptFlag) ||
-                             (!requiresColorAttrib && 0xffffffff == drawState.getColor());
+                             (!requiresColorAttrib && 0xffffffff == drawState.getColor()) ||
+                             (drawState.effectiveColorStageCount() > 0 && !(*drawState.getEffectiveColorStage(0).getEffect())->willUseInputColor());
 
-    int numEffects = (skipColor ? 0 : drawState.numColorStages()) +
-                     (skipCoverage ? 0 : drawState.numCoverageStages());
+    int numEffects = (skipColor ? 0 : drawState.effectiveColorStageCount()) +
+                     (skipCoverage ? 0 : drawState.effectiveCoverageStageCount());
 
     size_t newKeyLength = KeyLength(numEffects);
     bool allocChanged;
     desc->fKey.reset(newKeyLength, SkAutoMalloc::kAlloc_OnShrink, &allocChanged);
     if (allocChanged || !desc->fInitialized) {
         // make sure any padding in the header is zero if we we haven't used this allocation before.
         memset(desc->header(), 0, kHeaderSize);
     }
     // write the key length
     *desc->atOffset<uint32_t, kLengthOffset>() = newKeyLength;
 
     KeyHeader* header = desc->header();
     EffectKey* effectKeys = desc->effectKeys();
 
     int currEffectKey = 0;
     bool readsDst = false;
     bool readFragPosition = false;
     bool hasVertexCode = false;
     if (!skipColor) {
-        for (int s = 0; s < drawState.numColorStages(); ++s) {
+        for (int s = 0; s < drawState.effectiveColorStageCount(); ++s) {
             effectKeys[currEffectKey++] =
-                get_key_and_update_stats(drawState.getColorStage(s), gpu->glCaps(),
+                get_key_and_update_stats(drawState.getEffectiveColorStage(s), gpu->glCaps(),
                                          requiresLocalCoordAttrib, &readsDst, &readFragPosition,
                                          &hasVertexCode);
         }
     }
     if (!skipCoverage) {
-        for (int s = 0; s < drawState.numCoverageStages(); ++s) {
+        for (int s = 0; s < drawState.effectiveCoverageStageCount(); ++s) {
             effectKeys[currEffectKey++] =
-                get_key_and_update_stats(drawState.getCoverageStage(s), gpu->glCaps(),
+                get_key_and_update_stats(drawState.getEffectiveCoverageStage(s), gpu->glCaps(),
                                          requiresLocalCoordAttrib, &readsDst, &readFragPosition,
                                          &hasVertexCode);
         }
     }
 
     header->fHasVertexCode = hasVertexCode || requiresLocalCoordAttrib;
     header->fEmitsPointSize = isPoints;
-    header->fColorFilterXfermode = skipColor ? SkXfermode::kDst_Mode : drawState.getColorFilterMode();
 
     // Currently the experimental GS will only work with triangle prims (and it doesn't do anything
     // other than pass through values from the VS to the FS anyway).
 #if GR_GL_EXPERIMENTAL_GS
 #if 0
     header->fExperimentalGS = gpu->caps().geometryShaderSupport();
 #else
     header->fExperimentalGS = false;
 #endif
 #endif
@@ skipping 67 matching lines @@
 
     // Here we deal with whether/how we handle color and coverage separately.
 
     // Set these defaults and then possibly change our mind if there is coverage.
     header->fDiscardIfZeroCoverage = false;
     header->fCoverageOutput = kModulate_CoverageOutput;
 
     // If we do have coverage determine whether it matters.
     bool separateCoverageFromColor = false;
     if (!drawState.isCoverageDrawing() && !skipCoverage &&
-        (drawState.numCoverageStages() > 0 || requiresCoverageAttrib)) {
-        // color filter is applied between color/coverage computation
-        if (SkXfermode::kDst_Mode != header->fColorFilterXfermode) {
-            separateCoverageFromColor = true;
-        }
-
+        (drawState.effectiveCoverageStageCount() > 0 || requiresCoverageAttrib)) {
         // If we're stenciling then we want to discard samples that have zero coverage
         if (drawState.getStencil().doesWrite()) {
             header->fDiscardIfZeroCoverage = true;
             separateCoverageFromColor = true;
         }
 
         if (gpu->caps()->dualSourceBlendingSupport() &&
             !(blendOpts & (GrDrawState::kEmitCoverage_BlendOptFlag |
                            GrDrawState::kCoverageAsAlpha_BlendOptFlag))) {
             if (kZero_GrBlendCoeff == dstCoeff) {
@@ skipping 10 matching lines @@
                 separateCoverageFromColor = true;
             }
         } else if (readsDst &&
                    kOne_GrBlendCoeff == srcCoeff &&
                    kZero_GrBlendCoeff == dstCoeff) {
             header->fCoverageOutput = kCombineWithDst_CoverageOutput;
             separateCoverageFromColor = true;
         }
     }
     if (!skipColor) {
-        for (int s = 0; s < drawState.numColorStages(); ++s) {
-            colorStages->push_back(&drawState.getColorStage(s));
+        for (int s = 0; s < drawState.effectiveColorStageCount(); ++s) {
+            colorStages->push_back(&drawState.getEffectiveColorStage(s));
         }
-        header->fColorEffectCnt = drawState.numColorStages();
+        header->fColorEffectCnt = drawState.effectiveColorStageCount();
     }
     if (!skipCoverage) {
         SkTArray<const GrEffectStage*, true>* array;
         if (separateCoverageFromColor) {
             array = coverageStages;
-            header->fCoverageEffectCnt = drawState.numCoverageStages();
+            header->fCoverageEffectCnt = drawState.effectiveCoverageStageCount();
         } else {
             array = colorStages;
-            header->fColorEffectCnt += drawState.numCoverageStages();
+            header->fColorEffectCnt += drawState.effectiveCoverageStageCount();
         }
-        for (int s = 0; s < drawState.numCoverageStages(); ++s) {
-            array->push_back(&drawState.getCoverageStage(s));
+        for (int s = 0; s < drawState.effectiveCoverageStageCount(); ++s) {
+            array->push_back(&drawState.getEffectiveCoverageStage(s));
         }
     }
 
     *desc->checksum() = 0;
     *desc->checksum() = SkChecksum::Compute(reinterpret_cast<uint32_t*>(desc->fKey.get()),
                                             newKeyLength);
     desc->fInitialized = true;
 }
 
 GrGLProgramDesc& GrGLProgramDesc::operator= (const GrGLProgramDesc& other) {
     fInitialized = other.fInitialized;
     if (fInitialized) {
         size_t keyLength = other.keyLength();
         fKey.reset(keyLength);
         memcpy(fKey.get(), other.fKey.get(), keyLength);
     }
     return *this;
 }