GPU Gradients

src/effects/gradients/SkGradientShaderPriv.h

Index: src/effects/gradients/SkGradientShaderPriv.h
diff --git a/src/effects/gradients/SkGradientShaderPriv.h b/src/effects/gradients/SkGradientShaderPriv.h
index 31cc9f26171c6184b4535004ea1388d2de024bc4..875872f07b94eb214480df7f12d712e2f5172cb8 100644
--- a/src/effects/gradients/SkGradientShaderPriv.h
+++ b/src/effects/gradients/SkGradientShaderPriv.h
@@ -249,6 +249,8 @@ public:
     SkScalar getYCoord() const { return fYCoord; };
     const SkMatrix& getMatrix() const { return fMatrix;}
 
+    int numColors;

[reed1, 2013/08/13 12:33:41]

nit:
- does this guy really need to be public?
- why not name it fNumColors?

[dierk, 2013/08/13 19:50:17]

Done.

+
     virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
 
 protected:
@@ -301,6 +303,21 @@ protected:
         kMatrixKeyMask = (1 << kMatrixKeyBitCnt) - 1,
     };
 
+    static inline bool is2Color(const GrGradientEffect& e){

[bsalomon, 2013/08/13 14:28:37]

How about an enum named ColorType (or something like that) and values like
kTwoColor, kThreeColor, kTexture and have two functions (one for
GrGradientEffect and one for EffectKey) that return the type.

style-nit: static members have initial caps

Can you make the key values (0x4000 and 0x6000) enum values alongside
kMatrixKeyBitCnt above?  It might also be good to define them in terms of
kMatrixKeyBitCnt to ensure that they don't collide should
GrGLEffectMatrix::kKeyBits ever change.

[dierk, 2013/08/13 19:50:17]

Done.

+        return e.numColors == 2;
+    }
+    static inline bool is3Color(const GrGradientEffect& e){
+        return e.numColors == 3;
+    }
+
+    static inline bool is2Color(const EffectKey key){
+        return (key & 0x4000) == 0x4000;
+    }
+    static inline bool is3Color(const EffectKey key){
+        return (key & 0x6000) == 0x6000;
+    }
+    
+    
     /**
      * Subclasses must call this. It will return a value restricted to the lower kMatrixKeyBitCnt
      * bits.
@@ -323,22 +340,27 @@ protected:
 
     // Emits the uniform used as the y-coord to texture samples in derived classes. Subclasses
     // should call this method from their emitCode().
-    void emitYCoordUniform(GrGLShaderBuilder* builder);
+    void emitUniforms(GrGLShaderBuilder* builder, EffectKey key);
+
 
-    // emit code that gets a fragment's color from an expression for t; for now this always uses the
-    // texture, but for simpler cases we'll be able to lerp. Subclasses should call this method from
+    // emit code that gets a fragment's color from an expression for t; Only used if 4 or more

[bsalomon, 2013/08/13 14:28:37]

Do you mean the sampler array is only used for 4+? It seems like this function
is still called for all cases by the subclasses.

[dierk, 2013/08/13 19:50:17]

Done.

+    // colors, a simpler lerp is used for 2 and 3 colors. Subclasses should call this method from
     // their emitCode().
-    void emitColorLookup(GrGLShaderBuilder* builder,
-                         const char* gradientTValue,
-                         const char* outputColor,
-                         const char* inputColor,
-                         const GrGLShaderBuilder::TextureSampler&);
+    void emitColor(GrGLShaderBuilder* builder,
+                   const char* gradientTValue,
+                   EffectKey key,
+                   const char* outputColor,
+                   const char* inputColor,
+                   const GrGLShaderBuilder::TextureSamplerArray& samplers);
 
 private:
     static const GrEffect::CoordsType kCoordsType = GrEffect::kLocal_CoordsType;
 
     SkScalar fCachedYCoord;
     GrGLUniformManager::UniformHandle fFSYUni;
+    GrGLUniformManager::UniformHandle fColorStartUni;
+    GrGLUniformManager::UniformHandle fColorMidUni;
+    GrGLUniformManager::UniformHandle fColorEndUni;
     GrGLEffectMatrix fEffectMatrix;
 
     typedef GrGLEffect INHERITED;