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 "include/core/SkBlendMode.h" 14 #include "include/core/SkRefCnt.h" 15 #include "include/core/SkRegion.h" 16 #include "src/base/SkTLazy.h" 17 #include "src/gpu/ganesh/GrColor.h" 18 #include "src/gpu/ganesh/GrFragmentProcessor.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 * Sets a processor for color computation. 64 */ setColorFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp)65 void setColorFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp) { 66 SkASSERT(fp); 67 SkASSERT(fColorFragmentProcessor == nullptr); 68 fColorFragmentProcessor = std::move(fp); 69 fTrivial = false; 70 } 71 72 /** 73 * Appends an additional coverage processor to the coverage computation. 74 */ setCoverageFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp)75 void setCoverageFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp) { 76 SkASSERT(fp); 77 SkASSERT(fCoverageFragmentProcessor == nullptr); 78 fCoverageFragmentProcessor = std::move(fp); 79 fTrivial = false; 80 } 81 hasColorFragmentProcessor()82 bool hasColorFragmentProcessor() const { return fColorFragmentProcessor ? true : false; } hasCoverageFragmentProcessor()83 int hasCoverageFragmentProcessor() const { return fCoverageFragmentProcessor ? true : false; } numTotalFragmentProcessors()84 int numTotalFragmentProcessors() const { 85 return (this->hasColorFragmentProcessor() ? 1 : 0) + 86 (this->hasCoverageFragmentProcessor() ? 1 : 0); 87 } 88 getXPFactory()89 const GrXPFactory* getXPFactory() const { return fXPFactory; } 90 getColorFragmentProcessor()91 GrFragmentProcessor* getColorFragmentProcessor() const { 92 return fColorFragmentProcessor.get(); 93 } getCoverageFragmentProcessor()94 GrFragmentProcessor* getCoverageFragmentProcessor() const { 95 return fCoverageFragmentProcessor.get(); 96 } usesLocalCoords()97 bool usesLocalCoords() const { 98 // The sample coords for the top level FPs are implicitly the GP's local coords. 99 return (fColorFragmentProcessor && fColorFragmentProcessor->usesSampleCoords()) || 100 (fCoverageFragmentProcessor && fCoverageFragmentProcessor->usesSampleCoords()); 101 } 102 103 /** 104 * Returns true if the paint's output color will be constant after blending. If the result is 105 * true, constantColor will be updated to contain the constant color. Note that we can conflate 106 * coverage and color, so the actual values written to pixels with partial coverage may still 107 * not seem constant, even if this function returns true. 108 */ 109 bool isConstantBlendedColor(SkPMColor4f* constantColor) const; 110 111 /** 112 * A trivial paint is one that uses src-over and has no fragment processors. 113 * It may have variable sRGB settings. 114 **/ isTrivial()115 bool isTrivial() const { return fTrivial; } 116 assert_alive(GrPaint & p)117 friend void assert_alive(GrPaint& p) { 118 SkASSERT(p.fAlive); 119 } 120 121 private: 122 // Since paint copying is expensive if there are fragment processors, we require going through 123 // the Clone() method. 124 GrPaint(const GrPaint&); 125 GrPaint& operator=(const GrPaint&) = delete; 126 127 friend class GrProcessorSet; 128 129 const GrXPFactory* fXPFactory = nullptr; 130 std::unique_ptr<GrFragmentProcessor> fColorFragmentProcessor; 131 std::unique_ptr<GrFragmentProcessor> fCoverageFragmentProcessor; 132 bool fTrivial = true; 133 SkPMColor4f fColor = SK_PMColor4fWHITE; 134 SkDEBUGCODE(bool fAlive = true;) // Set false after moved from. 135 }; 136 137 #endif 138