Get gradient information for gpu effect directly from SkGradientShader instead of calling asAGradie…

src/effects/gradients/SkGradientShaderPriv.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkGradientShaderPriv_DEFINED
 #define SkGradientShaderPriv_DEFINED
 
@@ skipping 80 matching lines @@
         }
 
         const SkColor*      fColors;
         const SkScalar*     fPos;
         int                 fCount;
         SkShader::TileMode  fTileMode;
         SkUnitMapper*       fMapper;
         uint32_t            fFlags;
     };
 
+    // Specialized Descriptor used for setting up gpu gradient effect
+    struct DescriptorGpu {

[bsalomon, 2014/04/17 19:23:34]

How about we move the logic about whether it is a 2 or 3 color special case into
this new function so we don't have to return a t value and all the colors all
the time.

enum GpuColorType { ... } // moved from GrGradientEffect to SkGradientShader
struct GpuGradientDesc {
    GpuColorType fType;
    SkColor      fColors[3]; // only valid when fType is kTwo or kThree
    bool         fPremulAfterInterp;
    TileMode     fTileMode;
}

+        DescriptorGpu() {
+            sk_bzero(this, sizeof(*this));
+        }
+
+        SkColor*            fColors;
+        SkScalar            fMidPos;
+        int                 fCount;
+        SkShader::TileMode  fTileMode;
+        uint32_t            fFlags;
+    };
+
 public:
     SkGradientShaderBase(const Descriptor& desc);
     virtual ~SkGradientShaderBase();
 
     // The cache is initialized on-demand when getCache16/32 is called.
     class GradientShaderCache : public SkRefCnt {
     public:
         GradientShaderCache(U8CPU alpha, const SkGradientShaderBase& shader);
         ~GradientShaderCache();
 
@@ skipping 67 matching lines @@
         kCache32Count   = (1 << kCache32Bits),
         kCache32Shift   = 16 - kCache32Bits,
         kSqrt32Shift    = 8 - kCache32Bits,
 
         /// This value is used to *read* the dither cache; it may be 0
         /// if dithering is disabled.
         kDitherStride32 = kCache32Count,
         kDitherStride16 = kCache16Count,
     };
 
+    void getGradientDescriptorGpu(DescriptorGpu* desc) const;
+
 protected:
     SkGradientShaderBase(SkReadBuffer& );
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
     SK_TO_STRING_OVERRIDE()
 
     SkUnitMapper* fMapper;
     SkMatrix    fPtsToUnit;     // set by subclass
     TileMode    fTileMode;
     TileProc    fTileProc;
     int         fColorCount;
@@ skipping 225 matching lines @@
     GrGLUniformManager::UniformHandle fColorStartUni;
     GrGLUniformManager::UniformHandle fColorMidUni;
     GrGLUniformManager::UniformHandle fColorEndUni;
 
     typedef GrGLEffect INHERITED;
 };
 
 #endif
 
 #endif