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1 /*
2  * Copyright 2012 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef GrSingleTextureEffect_DEFINED
9 #define GrSingleTextureEffect_DEFINED
10 
11 #include "GrEffect.h"
12 #include "SkMatrix.h"
13 
14 class GrTexture;
15 
16 /**
17  * A base class for effects that draw a single texture with a texture matrix.
18  */
19 class GrSingleTextureEffect : public GrEffect {
20 public:
21     virtual ~GrSingleTextureEffect();
22 
getMatrix()23     const SkMatrix& getMatrix() const { return fMatrix; }
24 
25 protected:
26     GrSingleTextureEffect(GrTexture*, const SkMatrix&); /* unfiltered, clamp mode */
27     GrSingleTextureEffect(GrTexture*, const SkMatrix&, bool bilerp); /* clamp mode */
28     GrSingleTextureEffect(GrTexture*, const SkMatrix&, const GrTextureParams&);
29 
30     /**
31      * Helper for subclass onIsEqual() functions.
32      */
hasSameTextureParamsAndMatrix(const GrSingleTextureEffect & other)33     bool hasSameTextureParamsAndMatrix(const GrSingleTextureEffect& other) const {
34         const GrTextureAccess& otherAccess = other.fTextureAccess;
35         // We don't have to check the accesses' swizzles because they are inferred from the texture.
36         return fTextureAccess.getTexture() == otherAccess.getTexture() &&
37                fTextureAccess.getParams() == otherAccess.getParams() &&
38                this->getMatrix().cheapEqualTo(other.getMatrix());
39     }
40 
41     /**
42      * Can be used as a helper to implement subclass getConstantColorComponents(). It assumes that
43      * the subclass output color will be a modulation of the input color with a value read from the
44      * texture.
45      */
updateConstantColorComponentsForModulation(GrColor * color,uint32_t * validFlags)46     void updateConstantColorComponentsForModulation(GrColor* color, uint32_t* validFlags) const {
47         if ((*validFlags & kA_ValidComponentFlag) && 0xFF == GrColorUnpackA(*color) &&
48             GrPixelConfigIsOpaque(this->texture(0)->config())) {
49             *validFlags = kA_ValidComponentFlag;
50         } else {
51             *validFlags = 0;
52         }
53     }
54 
55 private:
56     GrTextureAccess fTextureAccess;
57     SkMatrix        fMatrix;
58 
59     typedef GrEffect INHERITED;
60 };
61 
62 #endif
63