Add Coverage Drawing XP

include/gpu/GrXferProcessor.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrXferProcessor_DEFINED
 #define GrXferProcessor_DEFINED
 
@@ skipping 68 matching lines @@
 
     /**
      * Determines which optimizations (as described by the ptFlags above) can be performed by
      * the draw with this xfer processor. If this function is called, the xfer processor may change
      * its state to reflected the given blend optimizations. If the XP needs to see a specific input
      * color to blend correctly, it will set the OverrideColor flag and the output parameter
      * overrideColor will be the required value that should be passed into the XP. 
      * A caller who calls this function on a XP is required to honor the returned OptFlags
      * and color values for its draw.
      */
-    // TODO: remove need for isCoverageDrawing once coverageDrawing is its own XP.
     // TODO: remove need for colorWriteDisabled once colorWriteDisabled is its own XP.
     virtual OptFlags getOptimizations(const GrProcOptInfo& colorPOI,
                                       const GrProcOptInfo& coveragePOI,
-                                      bool isCoverageDrawing,
                                       bool colorWriteDisabled,
                                       bool doesStencilWrite,
                                       GrColor* overrideColor,
                                       const GrDrawTargetCaps& caps) = 0;
 
     struct BlendInfo {
         GrBlendCoeff fSrcBlend;
         GrBlendCoeff fDstBlend;
         GrColor      fBlendConstant;
     };
@@ skipping 16 matching lines @@
         A return value of true from isEqual() should not be used to test whether the processor would
         generate the same shader code. To test for identical code generation use getGLProcessorKey*/
     
     bool isEqual(const GrXferProcessor& that) const {
         if (this->classID() != that.classID()) {
             return false;
         }
         return this->onIsEqual(that);
     }
    
-
 protected:
     GrXferProcessor() : fWillReadDstColor(false) {}
 
     /**
      * If the prceossor subclass will read the destination pixel value then it must call this
      * function from its constructor. Otherwise, when its generated backend-specific prceossor class
      * attempts to generate code that reads the destination pixel it will fail.
      */
     void setWillReadDstColor() { fWillReadDstColor = true; }
 
-    /**
-     * Subclass implements this to support getConstantColorComponents(...).
-     */
-    virtual void onComputeInvariantOutput(GrInvariantOutput* inout) const = 0;
-
 private:
     virtual bool onIsEqual(const GrXferProcessor&) const = 0;
 
     bool         fWillReadDstColor;
 
     typedef GrFragmentProcessor INHERITED;
 };
 
 GR_MAKE_BITFIELD_OPS(GrXferProcessor::OptFlags);
 
@@ skipping 18 matching lines @@
      * correctly blend when using RGB coverage. The knownColor and knownColorFlags represent the
      * final computed color from the color stages.
      */
     virtual bool supportsRGBCoverage(GrColor knownColor, uint32_t knownColorFlags) const = 0;
 
     /**
      * Depending on color blend mode requested it may or may not be possible to correctly blend with
      * fractional pixel coverage generated by the fragment shader.
      *
      * This function considers the known color and coverage input into the xfer processor and
-     * certain state information (isCoverageDrawing and colorWriteDisabled) to determine whether
+     * certain state information (colorWriteDisabled) to determine whether
      * coverage can be handled correctly.
      */
-    // TODO: remove need for isCoverageDrawing once coverageDrawing is its own XP.
     // TODO: remove need for colorWriteDisabled once colorWriteDisabled is its own XP.
     virtual bool canApplyCoverage(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
-                                  bool isCoverageDrawing, bool colorWriteDisabled) const = 0;
+                                  bool colorWriteDisabled) const = 0;
 
     /**
      * This function returns true if the destination pixel values will be read for blending during
      * draw.
      */
-    // TODO: remove need for isCoverageDrawing once coverageDrawing is its own XP.
     // TODO: remove need for colorWriteDisabled once only XP can read dst.
     virtual bool willBlendWithDst(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
-                                  bool isCoverageDrawing, bool colorWriteDisabled) const = 0;
+                                  bool colorWriteDisabled) const = 0;
 
     /**
      * Determines whether multiplying the computed per-pixel color by the pixel's fractional
      * coverage before the blend will give the correct final destination color. In general it
      * will not as coverage is applied after blending.
      */
-    // TODO: remove need for isCoverageDrawing once coverageDrawing is its own XP.
-    virtual bool canTweakAlphaForCoverage(bool isCoverageDrawing) const = 0;
+    virtual bool canTweakAlphaForCoverage() const = 0;
 
     virtual bool getOpaqueAndKnownColor(const GrProcOptInfo& colorPOI,
                                         const GrProcOptInfo& coveragePOI, GrColor* solidColor,
                                         uint32_t* solidColorKnownComponents) const = 0;
 
     bool isEqual(const GrXPFactory& that) const {
         if (this->classID() != that.classID()) {
             return false;
         }
         return this->onIsEqual(that);
@@ skipping 34 matching lines @@
     enum {
         kIllegalXPFClassID = 0,
     };
     static int32_t gCurrXPFClassID;
 
     typedef GrProgramElement INHERITED;
 };
 
 #endif