Add support for reading the dst pixel value in an effect. Use in a new effect for the kDarken xfer …

src/gpu/GrGpu.cpp

 
 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGpu.h"
@@ skipping 312 matching lines @@
                 GrCrash("Can't get vertices into buffer!");
             }
         }
     }
 
     return fUnitSquareVertexBuffer;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
-bool GrGpu::setupClipAndFlushState(DrawType type) {
+bool GrGpu::setupClipAndFlushState(DrawType type, const GrDeviceCoordTexture* dstCopy) {
 
     if (!fClipMaskManager.setupClipping(this->getClip())) {
         return false;
     }
 
-    if (!this->flushGraphicsState(type)) {
+    if (!this->flushGraphicsState(type, dstCopy)) {
         return false;
     }
 
     return true;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 void GrGpu::geometrySourceWillPush() {
     const GeometrySrcState& geoSrc = this->getGeomSrc();
@@ skipping 17 matching lines @@
 }
 
 void GrGpu::geometrySourceWillPop(const GeometrySrcState& restoredState) {
     // if popping last entry then pops are unbalanced with pushes
     GrAssert(fGeomPoolStateStack.count() > 1);
     fGeomPoolStateStack.pop_back();
 }
 
 void GrGpu::onDraw(const DrawInfo& info) {
     this->handleDirtyContext();
-    if (!this->setupClipAndFlushState(PrimTypeToDrawType(info.primitiveType()))) {
+    if (!this->setupClipAndFlushState(PrimTypeToDrawType(info.primitiveType()), info.dstCopy())) {
         return;
     }
     this->onGpuDraw(info);
 }
 
 void GrGpu::onStencilPath(const GrPath* path, const SkStrokeRec&, SkPath::FillType fill) {
     this->handleDirtyContext();
 
     // TODO: make this more efficient (don't copy and copy back)
     GrAutoTRestore<GrStencilSettings> asr(this->drawState()->stencil());
 
     this->setStencilPathSettings(*path, fill, this->drawState()->stencil());
-    if (!this->setupClipAndFlushState(kStencilPath_DrawType)) {
+    if (!this->setupClipAndFlushState(kStencilPath_DrawType, NULL)) {
         return;
     }
 
     this->onGpuStencilPath(path, fill);
 }
 
 void GrGpu::finalizeReservedVertices() {
     GrAssert(NULL != fVertexPool);
     fVertexPool->unlock();
 }
@@ skipping 123 matching lines @@
 }
 
 void GrGpu::releaseIndexArray() {
     // if index source was array, we stowed data in the pool
     const GeometrySrcState& geoSrc = this->getGeomSrc();
     GrAssert(kArray_GeometrySrcType == geoSrc.fIndexSrc);
     size_t bytes = geoSrc.fIndexCount * sizeof(uint16_t);
     fIndexPool->putBack(bytes);
     --fIndexPoolUseCnt;
 }