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 #ifndef GrPaint_DEFINED 9 #define GrPaint_DEFINED 10 11 #include "include/core/SkRegion.h" 12 #include "include/private/SkColorData.h" 13 #include "include/private/base/SkAssert.h" 14 #include "include/private/base/SkDebug.h" 15 #include "include/private/base/SkTo.h" 16 #include "src/gpu/ganesh/GrFragmentProcessor.h" 17 18 #include <memory> 19 #include <utility> 20 21 class GrXPFactory; 22 enum class SkBlendMode; 23 24 /** 25 * The paint describes how color and coverage are computed at each pixel by GrContext draw 26 * functions and the how color is blended with the destination pixel. 27 * 28 * The paint allows installation of custom color and coverage stages. New types of stages are 29 * created by subclassing GrProcessor. 30 * 31 * The primitive color computation starts with the color specified by setColor(). This color is the 32 * input to the first color stage. Each color stage feeds its output to the next color stage. 33 * 34 * Fractional pixel coverage follows a similar flow. The GrGeometryProcessor (specified elsewhere) 35 * provides the initial coverage which is passed to the first coverage fragment processor, which 36 * feeds its output to next coverage fragment processor. 37 * 38 * setXPFactory is used to control blending between the output color and dest. It also implements 39 * the application of fractional coverage from the coverage pipeline. 40 */ 41 class GrPaint { 42 public: 43 GrPaint() = default; 44 ~GrPaint() = default; 45 Clone(const GrPaint & src)46 static GrPaint Clone(const GrPaint& src) { return GrPaint(src); } 47 48 /** 49 * The initial color of the drawn primitive. Defaults to solid white. 50 */ setColor4f(const SkPMColor4f & color)51 void setColor4f(const SkPMColor4f& color) { fColor = color; } getColor4f()52 const SkPMColor4f& getColor4f() const { return fColor; } 53 setXPFactory(const GrXPFactory * xpFactory)54 void setXPFactory(const GrXPFactory* xpFactory) { 55 fXPFactory = xpFactory; 56 fTrivial &= !SkToBool(xpFactory); 57 } 58 59 void setPorterDuffXPFactory(SkBlendMode mode); 60 61 void setCoverageSetOpXPFactory(SkRegion::Op, bool invertCoverage = false); 62 63 /** 64 * Sets a processor for color computation. 65 */ setColorFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp)66 void setColorFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp) { 67 SkASSERT(fp); 68 SkASSERT(fColorFragmentProcessor == nullptr); 69 fColorFragmentProcessor = std::move(fp); 70 fTrivial = false; 71 } 72 73 /** 74 * Appends an additional coverage processor to the coverage computation. 75 */ setCoverageFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp)76 void setCoverageFragmentProcessor(std::unique_ptr<GrFragmentProcessor> fp) { 77 SkASSERT(fp); 78 SkASSERT(fCoverageFragmentProcessor == nullptr); 79 fCoverageFragmentProcessor = std::move(fp); 80 fTrivial = false; 81 } 82 hasColorFragmentProcessor()83 bool hasColorFragmentProcessor() const { return fColorFragmentProcessor ? true : false; } hasCoverageFragmentProcessor()84 int hasCoverageFragmentProcessor() const { return fCoverageFragmentProcessor ? true : false; } numTotalFragmentProcessors()85 int numTotalFragmentProcessors() const { 86 return (this->hasColorFragmentProcessor() ? 1 : 0) + 87 (this->hasCoverageFragmentProcessor() ? 1 : 0); 88 } 89 getXPFactory()90 const GrXPFactory* getXPFactory() const { return fXPFactory; } 91 getColorFragmentProcessor()92 GrFragmentProcessor* getColorFragmentProcessor() const { 93 return fColorFragmentProcessor.get(); 94 } getCoverageFragmentProcessor()95 GrFragmentProcessor* getCoverageFragmentProcessor() const { 96 return fCoverageFragmentProcessor.get(); 97 } usesLocalCoords()98 bool usesLocalCoords() const { 99 // The sample coords for the top level FPs are implicitly the GP's local coords. 100 return (fColorFragmentProcessor && fColorFragmentProcessor->usesSampleCoords()) || 101 (fCoverageFragmentProcessor && fCoverageFragmentProcessor->usesSampleCoords()); 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 std::unique_ptr<GrFragmentProcessor> fColorFragmentProcessor; 132 std::unique_ptr<GrFragmentProcessor> fCoverageFragmentProcessor; 133 bool fTrivial = true; 134 SkPMColor4f fColor = SK_PMColor4fWHITE; 135 SkDEBUGCODE(bool fAlive = true;) // Set false after moved from. 136 }; 137 138 #endif 139