Use texture barriers to read directly from the RT

src/gpu/GrDrawTarget.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 "GrDrawTarget.h"
 
@@ skipping 60 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 
 bool GrDrawTarget::setupDstReadIfNecessary(const GrPipelineBuilder& pipelineBuilder,
                                            const GrProcOptInfo& colorPOI,
                                            const GrProcOptInfo& coveragePOI,
                                            GrDeviceCoordTexture* dstCopy,
                                            const SkRect* drawBounds) {
     if (!pipelineBuilder.willXPNeedDstCopy(*this->caps(), colorPOI, coveragePOI)) {
         return true;
     }
+
+    GrRenderTarget* rt = pipelineBuilder.getRenderTarget();
+
+    if (this->caps()->textureBarrierSupport()) {
+        if (GrTexture* rtTex = rt->asTexture()) {
+            // The render target is a texture, se we can read from it directly in the shader. The XP
+            // will be responsible to detect this situation and request a texture barrier.
+            dstCopy->setTexture(rtTex);
+            dstCopy->setOffset(0, 0);
+            return true;
+        }
+    }
+
     SkIRect copyRect;
-    GrRenderTarget* rt = pipelineBuilder.getRenderTarget();
     pipelineBuilder.clip().getConservativeBounds(rt, &copyRect);
 
     if (drawBounds) {
         SkIRect drawIBounds;
         drawBounds->roundOut(&drawIBounds);
         if (!copyRect.intersect(drawIBounds)) {
 #ifdef SK_DEBUG
             SkDebugf("Missed an early reject. Bailing on draw from setupDstReadIfNecessary.\n");
 #endif
             return false;
@@ skipping 663 matching lines @@
                              GrPipelineBuilder::AutoRestoreFragmentProcessors* arfp,
                              GrPipelineBuilder::AutoRestoreStencil* ars,
                              GrScissorState* scissorState,
                              const SkRect* devBounds) {
     return fClipMaskManager.setupClipping(pipelineBuilder,
                                           arfp,
                                           ars,
                                           scissorState,
                                           devBounds);
 }