Add "sample locations" feature to GrProcessor

src/gpu/GrPipeline.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrPipeline_DEFINED
 #define GrPipeline_DEFINED
 
@@ skipping 127 matching lines @@
      * @return    The currently set render target.
      */
     GrRenderTarget* getRenderTarget() const { return fRenderTarget.get(); }
 
     const GrStencilSettings& getStencil() const { return fStencilSettings; }
 
     const GrScissorState& getScissorState() const { return fScissorState; }
 
     bool isHWAntialiasState() const { return SkToBool(fFlags & kHWAA_Flag); }
     bool snapVerticesToPixelCenters() const { return SkToBool(fFlags & kSnapVertices_Flag); }
+    bool hasSampleLocations() const { return SkToBool(fFlags & kSampleLocations_Flag); }
 
     GrXferBarrierType xferBarrierType(const GrCaps& caps) const {
         return this->getXferProcessor().xferBarrierType(fRenderTarget.get(), caps);
     }
 
     /**
      * Gets whether the target is drawing clockwise, counterclockwise,
      * or both faces.
      * @return the current draw face(s).
      */
     GrPipelineBuilder::DrawFace getDrawFace() const { return fDrawFace; }
 
 
     ///////////////////////////////////////////////////////////////////////////
 
     bool readsFragPosition() const { return fReadsFragPosition; }
     bool ignoresCoverage() const { return fIgnoresCoverage; }
 
+    ///////////////////////////////////////////////////////////////////////////
+
+    /**
+     * Returns the actual number of samples the hardware will run when using this pipeline.
+     * NOTE: this can be greater than the sample count in the render target's surface descriptor.
+     */
+    int effectiveSampleCount() const { return this->getMultisampleSpecs().fEffectiveSampleCnt; }
+
+    /**
+     * Returns a unique ID that identifies this pipeline's sample pattern, or 0 if sample locations
+     * are not supported.
+     */
+    uint16_t getSamplePatternID() const { return this->getMultisampleSpecs().fSamplePatternID; }
+
+    /**
+     * Returns this pipeline's sample locations, or nullptr if sample locations are not supported.
+     * The locations are stored as offsets in device space from the center of the pixel.
+     */
+    const SkPoint* getSampleLocations() const {
+        return this->getMultisampleSpecs().fSampleLocations;
+    }
+
 private:
     GrPipeline() { /** Initialized in factory function*/ }
 
     /**
      * Alter the program desc and inputs (attribs and processors) based on the blend optimization.
      */
     void adjustProgramFromOptimizations(const GrPipelineBuilder& ds,
                                         GrXferProcessor::OptFlags,
                                         const GrProcOptInfo& colorPOI,
                                         const GrProcOptInfo& coveragePOI,
                                         int* firstColorProcessorIdx,
                                         int* firstCoverageProcessorIdx);
 
     /**
      * Calculates the primary and secondary output types of the shader. For certain output types
      * the function may adjust the blend coefficients. After this function is called the src and dst
      * blend coeffs will represent those used by backend API.
      */
     void setOutputStateInfo(const GrPipelineBuilder& ds, GrXferProcessor::OptFlags,
                             const GrCaps&);
 
+    const GrRenderTargetPriv::MultisampleSpecs& getMultisampleSpecs() const {

[bsalomon, 2016/02/22 20:28:25]

We anticipate render target being removed from pipeline and being a property of
GrDrawTarget (once the multi-draw buffer change is complete and each draw target
contains draws for only one render target). Wondering how this will evolve in
that world.

[Chris Dalton, 2016/02/22 21:19:11]

I imagine it would be straightforward, but I can only guess since I'm really in
the dark when it comes to future plans :-(

+        SkASSERT(this->isHWAntialiasState());
+        return this->getRenderTarget()->renderTargetPriv().getMultisampleSpecs(fStencilSettings);
+    }
+
     enum Flags {
         kHWAA_Flag              = 0x1,
         kSnapVertices_Flag      = 0x2,
+        kSampleLocations_Flag   = 0x4,
     };
 
     typedef GrPendingIOResource<GrRenderTarget, kWrite_GrIOType> RenderTarget;
     typedef GrPendingProgramElement<const GrFragmentProcessor> PendingFragmentProcessor;
     typedef SkAutoSTArray<8, PendingFragmentProcessor> FragmentProcessorArray;
     typedef GrPendingProgramElement<const GrXferProcessor> ProgramXferProcessor;
     RenderTarget                        fRenderTarget;
     GrScissorState                      fScissorState;
     GrStencilSettings                   fStencilSettings;
     GrPipelineBuilder::DrawFace         fDrawFace;
     uint32_t                            fFlags;
     ProgramXferProcessor                fXferProcessor;
     FragmentProcessorArray              fFragmentProcessors;
     bool                                fReadsFragPosition;
     bool                                fIgnoresCoverage;
 
     // This value is also the index in fFragmentProcessors where coverage processors begin.
     int                                 fNumColorProcessors;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif