added support for PLS path rendering

src/gpu/effects/GrPorterDuffXferProcessor.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "effects/GrPorterDuffXferProcessor.h"
 
 #include "GrBlend.h"
@@ skipping 729 matching lines @@
         return nullptr;
     }
     return SkRef(gFactories[xfermode]);
 }
 
 GrXferProcessor*
 GrPorterDuffXPFactory::onCreateXferProcessor(const GrCaps& caps,
                                              const GrPipelineOptimizations& optimizations,
                                              bool hasMixedSamples,
                                              const DstTexture* dstTexture) const {
+    if (optimizations.fOverrides.fUsePLSDstRead) {

[bsalomon, 2016/01/04 15:33:47]

Maybe time to rename GrPipelineOptimizations... seems like this isn't an
optimization but rather a requirement for correct rendering.

+        return new ShaderPDXferProcessor(dstTexture, hasMixedSamples, fXfermode);
+    }
     BlendFormula blendFormula;
     if (optimizations.fCoveragePOI.isFourChannelOutput()) {
         if (SkXfermode::kSrcOver_Mode == fXfermode &&
             kRGBA_GrColorComponentFlags == optimizations.fColorPOI.validFlags() &&
             !caps.shaderCaps()->dualSourceBlendingSupport() &&
             !caps.shaderCaps()->dstReadInShaderSupport()) {
             // If we don't have dual source blending or in shader dst reads, we fall back to this
             // trick for rendering SrcOver LCD text instead of doing a dst copy.
             SkASSERT(!dstTexture || !dstTexture->texture());
             return PDLCDXferProcessor::Create(fXfermode, optimizations.fColorPOI);
@@ skipping 39 matching lines @@
 
         default:
             blendedColor->fKnownColorFlags = kNone_GrColorComponentFlags;
             return;
     }
 }
 
 bool GrPorterDuffXPFactory::willReadDstColor(const GrCaps& caps,
                                              const GrPipelineOptimizations& optimizations,
                                              bool hasMixedSamples) const {
+    if (optimizations.fOverrides.fUsePLSDstRead) {
+        return true;
+    }
     if (caps.shaderCaps()->dualSourceBlendingSupport()) {
         return false;
     }
     
     // When we have four channel coverage we always need to read the dst in order to correctly
     // blend. The one exception is when we are using srcover mode and we know the input color into
     // the XP.
     if (optimizations.fCoveragePOI.isFourChannelOutput()) {
         if (SkXfermode::kSrcOver_Mode == fXfermode &&
             kRGBA_GrColorComponentFlags == optimizations.fColorPOI.validFlags() &&
@@ skipping 30 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////////////////////
 // SrcOver Global functions
 ////////////////////////////////////////////////////////////////////////////////////////////////
 
 GrXferProcessor* GrPorterDuffXPFactory::CreateSrcOverXferProcessor(
         const GrCaps& caps,
         const GrPipelineOptimizations& optimizations,
         bool hasMixedSamples,
         const GrXferProcessor::DstTexture* dstTexture) {
+    if (optimizations.fOverrides.fUsePLSDstRead) {
+        return new ShaderPDXferProcessor(dstTexture, hasMixedSamples, SkXfermode::kSrcOver_Mode);
+    }
     if (!optimizations.fCoveragePOI.isFourChannelOutput() &&
         !(optimizations.fCoveragePOI.isSolidWhite() &&
           !hasMixedSamples &&
           optimizations.fColorPOI.isOpaque())) {
         static BlendFormula gSrcOverBlendFormula = COEFF_FORMULA(kOne_GrBlendCoeff,
                                                                  kISA_GrBlendCoeff);
         static PorterDuffXferProcessor gSrcOverXP(gSrcOverBlendFormula);
         SkASSERT(!dstTexture || !dstTexture->texture());
         gSrcOverXP.ref();
         return &gSrcOverXP;
@@ skipping 42 matching lines @@
         }
         return get_lcd_blend_formula(optimizations.fCoveragePOI, 
                                      SkXfermode::kSrcOver_Mode).hasSecondaryOutput();
     }
     // We fallback on the shader XP when the blend formula would use dual source blending but we
     // don't have support for it.
     return get_blend_formula(optimizations.fColorPOI, optimizations.fCoveragePOI,
                              hasMixedSamples, SkXfermode::kSrcOver_Mode).hasSecondaryOutput();
 }