Implement support for mixed sampled render targets

src/gpu/GrPipeline.cpp

Index: src/gpu/GrPipeline.cpp
diff --git a/src/gpu/GrPipeline.cpp b/src/gpu/GrPipeline.cpp
index 906426caaaecc0699dd8d878ee2ccdfa9bdfd6dd..6502829bfebf19275e8f517baa74c6ddcf117b0d 100644
--- a/src/gpu/GrPipeline.cpp
+++ b/src/gpu/GrPipeline.cpp
@@ -29,11 +29,21 @@ GrPipeline::GrPipeline(const GrPipelineBuilder& pipelineBuilder,
         overrideColor = colorPOI.inputColorToEffectiveStage();
     }
 
+    fRenderTarget.reset(pipelineBuilder.fRenderTarget.get());
+    SkASSERT(fRenderTarget);
+
     GrXferProcessor::OptFlags optFlags;
     if (xferProcessor) {
         fXferProcessor.reset(xferProcessor.get());
 
-        optFlags = xferProcessor->getOptimizations(colorPOI,
+        GrProcOptInfo localColorPOI = colorPOI;
+        // Optimizations will try to turn off blending which is required by mixed
+        // sampled modes.
+        bool isMixedSampledTarget =
+            (this->getRenderTarget()->sampleConfig() == kStencil_GrSampleConfig);
+        localColorPOI.setNeedsCoverageModulation(isMixedSampledTarget);

[Chris Dalton, 2015/03/14 02:51:30]

No need to force blending unless we're actually using the mixed samples: (after
https://codereview.chromium.org/1002013006/)

 localColorPOI.setNeedsCoverageModulation(pipelineBuilder.isHWAntialias() &&
isMixedSampledTarget);

(Or we may want to move the block that sets fFlags to before this line, then
say:

  localColorPOI.setNeedsCoverageModulation(this->isHWAntialiasState() &&
isMixedSampledTarget);

)

+
+        optFlags = xferProcessor->getOptimizations(localColorPOI,
                                                    coveragePOI,
                                                    pipelineBuilder.getStencil().doesWrite(),
                                                    &overrideColor,
@@ -51,8 +61,6 @@ GrPipeline::GrPipeline(const GrPipelineBuilder& pipelineBuilder,
         return;
     }
 
-    fRenderTarget.reset(pipelineBuilder.fRenderTarget.get());
-    SkASSERT(fRenderTarget);
     fScissorState = scissorState;
     fStencilSettings = pipelineBuilder.getStencil();
     fDrawFace = pipelineBuilder.getDrawFace();