1 2 /* 3 * Copyright 2011 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 #ifndef GrPaint_DEFINED 11 #define GrPaint_DEFINED 12 13 #include "GrColor.h" 14 #include "GrFragmentProcessor.h" 15 #include "SkBlendMode.h" 16 #include "SkRefCnt.h" 17 #include "SkRegion.h" 18 #include "SkTLazy.h" 19 20 class GrTextureProxy; 21 class GrXPFactory; 22 23 /** 24 * The paint describes how color and coverage are computed at each pixel by GrContext draw 25 * functions and the how color is blended with the destination pixel. 26 * 27 * The paint allows installation of custom color and coverage stages. New types of stages are 28 * created by subclassing GrProcessor. 29 * 30 * The primitive color computation starts with the color specified by setColor(). This color is the 31 * input to the first color stage. Each color stage feeds its output to the next color stage. 32 * 33 * Fractional pixel coverage follows a similar flow. The GrGeometryProcessor (specified elsewhere) 34 * provides the initial coverage which is passed to the first coverage fragment processor, which 35 * feeds its output to next coverage fragment processor. 36 * 37 * setXPFactory is used to control blending between the output color and dest. It also implements 38 * the application of fractional coverage from the coverage pipeline. 39 */ 40 class GrPaint { 41 public: 42 GrPaint() = default; 43 ~GrPaint() = default; 44 Clone(const GrPaint & src)45 static GrPaint Clone(const GrPaint& src) { return GrPaint(src); } 46 47 /** 48 * The initial color of the drawn primitive. Defaults to solid white. 49 */ setColor4f(const SkPMColor4f & color)50 void setColor4f(const SkPMColor4f& color) { fColor = color; } getColor4f()51 const SkPMColor4f& getColor4f() const { return fColor; } 52 setXPFactory(const GrXPFactory * xpFactory)53 void setXPFactory(const GrXPFactory* xpFactory) { 54 fXPFactory = xpFactory; 55 fTrivial &= !SkToBool(xpFactory); 56 } 57 58 void setPorterDuffXPFactory(SkBlendMode mode); 59 60 void setCoverageSetOpXPFactory(SkRegion::Op, bool invertCoverage = false); 61 62 /** 63 * Appends an additional color processor to the color computation. 64 */ addColorFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp)65 void addColorFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp) { 66 SkASSERT(fp); 67 fColorFragmentProcessors.push_back(std::move(fp)); 68 fTrivial = false; 69 } 70 71 /** 72 * Appends an additional coverage processor to the coverage computation. 73 */ addCoverageFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp)74 void addCoverageFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp) { 75 SkASSERT(fp); 76 fCoverageFragmentProcessors.push_back(std::move(fp)); 77 fTrivial = false; 78 } 79 80 /** 81 * Helpers for adding color or coverage effects that sample a texture. The matrix is applied 82 * to the src space position to compute texture coordinates. 83 */ 84 void addColorTextureProcessor(sk_sp<GrTextureProxy>, const SkMatrix&); 85 void addColorTextureProcessor(sk_sp<GrTextureProxy>, const SkMatrix&, const GrSamplerState&); 86 87 void addCoverageTextureProcessor(sk_sp<GrTextureProxy>, const SkMatrix&); 88 void addCoverageTextureProcessor(sk_sp<GrTextureProxy>, const SkMatrix&, const GrSamplerState&); 89 numColorFragmentProcessors()90 int numColorFragmentProcessors() const { return fColorFragmentProcessors.count(); } numCoverageFragmentProcessors()91 int numCoverageFragmentProcessors() const { return fCoverageFragmentProcessors.count(); } numTotalFragmentProcessors()92 int numTotalFragmentProcessors() const { return this->numColorFragmentProcessors() + 93 this->numCoverageFragmentProcessors(); } 94 getXPFactory()95 const GrXPFactory* getXPFactory() const { return fXPFactory; } 96 getColorFragmentProcessor(int i)97 GrFragmentProcessor* getColorFragmentProcessor(int i) const { 98 return fColorFragmentProcessors[i].get(); 99 } getCoverageFragmentProcessor(int i)100 GrFragmentProcessor* getCoverageFragmentProcessor(int i) const { 101 return fCoverageFragmentProcessors[i].get(); 102 } 103 104 /** 105 * Returns true if the paint's output color will be constant after blending. If the result is 106 * true, constantColor will be updated to contain the constant color. Note that we can conflate 107 * coverage and color, so the actual values written to pixels with partial coverage may still 108 * not seem constant, even if this function returns true. 109 */ 110 bool isConstantBlendedColor(SkPMColor4f* constantColor) const; 111 112 /** 113 * A trivial paint is one that uses src-over and has no fragment processors. 114 * It may have variable sRGB settings. 115 **/ isTrivial()116 bool isTrivial() const { return fTrivial; } 117 assert_alive(GrPaint & p)118 friend void assert_alive(GrPaint& p) { 119 SkASSERT(p.fAlive); 120 } 121 122 private: 123 // Since paint copying is expensive if there are fragment processors, we require going through 124 // the Clone() method. 125 GrPaint(const GrPaint&); 126 GrPaint& operator=(const GrPaint&) = delete; 127 128 friend class GrProcessorSet; 129 130 const GrXPFactory* fXPFactory = nullptr; 131 SkSTArray<4, std::unique_ptr<GrFragmentProcessor>> fColorFragmentProcessors; 132 SkSTArray<2, std::unique_ptr<GrFragmentProcessor>> fCoverageFragmentProcessors; 133 bool fTrivial = true; 134 SkPMColor4f fColor = SK_PMColor4fWHITE; 135 SkDEBUGCODE(bool fAlive = true;) // Set false after moved from. 136 }; 137 138 #endif 139