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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrPaint_DEFINED
#define GrPaint_DEFINED
#include "GrColor.h"
#include "GrColorSpaceXform.h"
#include "GrFragmentProcessor.h"
#include "SkBlendMode.h"
#include "SkRefCnt.h"
#include "SkRegion.h"
#include "SkTLazy.h"
class GrTextureProxy;
class GrXPFactory;
/**
* The paint describes how color and coverage are computed at each pixel by GrContext draw
* functions and the how color is blended with the destination pixel.
*
* The paint allows installation of custom color and coverage stages. New types of stages are
* created by subclassing GrProcessor.
*
* The primitive color computation starts with the color specified by setColor(). This color is the
* input to the first color stage. Each color stage feeds its output to the next color stage.
*
* Fractional pixel coverage follows a similar flow. The GrGeometryProcessor (specified elsewhere)
* provides the initial coverage which is passed to the first coverage fragment processor, which
* feeds its output to next coverage fragment processor.
*
* setXPFactory is used to control blending between the output color and dest. It also implements
* the application of fractional coverage from the coverage pipeline.
*/
class GrPaint {
public:
GrPaint() = default;
explicit GrPaint(const GrPaint&) = default;
~GrPaint() = default;
/**
* The initial color of the drawn primitive. Defaults to solid white.
*/
void setColor4f(const GrColor4f& color) { fColor = color; }
const GrColor4f& getColor4f() const { return fColor; }
/**
* Legacy getter, until all code handles 4f directly.
*/
GrColor getColor() const { return fColor.toGrColor(); }
/**
* Should shader output conversion from linear to sRGB be disabled.
* Only relevant if the destination is sRGB. Defaults to false.
*/
void setDisableOutputConversionToSRGB(bool srgb) { fDisableOutputConversionToSRGB = srgb; }
bool getDisableOutputConversionToSRGB() const { return fDisableOutputConversionToSRGB; }
/**
* Should sRGB inputs be allowed to perform sRGB to linear conversion. With this flag
* set to false, sRGB textures will be treated as linear (including filtering).
*/
void setAllowSRGBInputs(bool allowSRGBInputs) { fAllowSRGBInputs = allowSRGBInputs; }
bool getAllowSRGBInputs() const { return fAllowSRGBInputs; }
/**
* Does one of the fragment processors need a field of distance vectors to the nearest edge?
*/
bool usesDistanceVectorField() const { return fUsesDistanceVectorField; }
/**
* Should rendering be gamma-correct, end-to-end. Causes sRGB render targets to behave
* as such (with linear blending), and sRGB inputs to be filtered and decoded correctly.
*/
void setGammaCorrect(bool gammaCorrect) {
setDisableOutputConversionToSRGB(!gammaCorrect);
setAllowSRGBInputs(gammaCorrect);
}
void setXPFactory(const GrXPFactory* xpFactory) { fXPFactory = xpFactory; }
void setPorterDuffXPFactory(SkBlendMode mode);
void setCoverageSetOpXPFactory(SkRegion::Op, bool invertCoverage = false);
/**
* Appends an additional color processor to the color computation.
*/
void addColorFragmentProcessor(sk_sp<GrFragmentProcessor> fp) {
SkASSERT(fp);
fUsesDistanceVectorField |= fp->usesDistanceVectorField();
fColorFragmentProcessors.push_back(std::move(fp));
}
/**
* Appends an additional coverage processor to the coverage computation.
*/
void addCoverageFragmentProcessor(sk_sp<GrFragmentProcessor> fp) {
SkASSERT(fp);
fUsesDistanceVectorField |= fp->usesDistanceVectorField();
fCoverageFragmentProcessors.push_back(std::move(fp));
}
/**
* Helpers for adding color or coverage effects that sample a texture. The matrix is applied
* to the src space position to compute texture coordinates.
*/
void addColorTextureProcessor(GrTexture*, sk_sp<GrColorSpaceXform>, const SkMatrix&);
void addCoverageTextureProcessor(GrTexture*, const SkMatrix&);
void addColorTextureProcessor(GrTexture*, sk_sp<GrColorSpaceXform>, const SkMatrix&,
const GrSamplerParams&);
void addCoverageTextureProcessor(GrTexture*, const SkMatrix&, const GrSamplerParams&);
void addColorTextureProcessor(GrContext*, sk_sp<GrTextureProxy>, sk_sp<GrColorSpaceXform>,
const SkMatrix&);
void addColorTextureProcessor(GrContext*, sk_sp<GrTextureProxy>, sk_sp<GrColorSpaceXform>,
const SkMatrix&, const GrSamplerParams&);
void addCoverageTextureProcessor(GrContext*, sk_sp<GrTextureProxy>, const SkMatrix&);
void addCoverageTextureProcessor(GrContext*, sk_sp<GrTextureProxy>,
const SkMatrix&, const GrSamplerParams&);
int numColorFragmentProcessors() const { return fColorFragmentProcessors.count(); }
int numCoverageFragmentProcessors() const { return fCoverageFragmentProcessors.count(); }
int numTotalFragmentProcessors() const { return this->numColorFragmentProcessors() +
this->numCoverageFragmentProcessors(); }
const GrXPFactory* getXPFactory() const { return fXPFactory; }
GrFragmentProcessor* getColorFragmentProcessor(int i) const {
return fColorFragmentProcessors[i].get();
}
GrFragmentProcessor* getCoverageFragmentProcessor(int i) const {
return fCoverageFragmentProcessors[i].get();
}
/**
* Returns true if the paint's output color will be constant after blending. If the result is
* true, constantColor will be updated to contain the constant color. Note that we can conflate
* coverage and color, so the actual values written to pixels with partial coverage may still
* not seem constant, even if this function returns true.
*/
bool isConstantBlendedColor(GrColor* constantColor) const;
private:
template <bool> class MoveOrImpl;
public:
/**
* A temporary instance of this class can be used to select between moving an existing paint or
* a temporary copy of an existing paint into a call site. MoveOrClone(paint, false) is a rvalue
* reference to paint while MoveOrClone(paint, true) is a rvalue reference to a copy of paint.
*/
using MoveOrClone = MoveOrImpl<true>;
/**
* A temporary instance of this class can be used to select between moving an existing or a
* newly default constructed paint into a call site. MoveOrNew(paint, false) is a rvalue
* reference to paint while MoveOrNew(paint, true) is a rvalue reference to a default paint.
*/
using MoveOrNew = MoveOrImpl<false>;
private:
GrPaint& operator=(const GrPaint&) = delete;
friend class GrProcessorSet;
const GrXPFactory* fXPFactory = nullptr;
SkSTArray<4, sk_sp<GrFragmentProcessor>> fColorFragmentProcessors;
SkSTArray<2, sk_sp<GrFragmentProcessor>> fCoverageFragmentProcessors;
bool fDisableOutputConversionToSRGB = false;
bool fAllowSRGBInputs = false;
bool fUsesDistanceVectorField = false;
GrColor4f fColor = GrColor4f::OpaqueWhite();
};
/** This is the implementation of MoveOrCopy and MoveOrNew. */
template <bool COPY_IF_NEW>
class GrPaint::MoveOrImpl {
public:
MoveOrImpl(GrPaint& paint, bool newPaint) {
if (newPaint) {
if (COPY_IF_NEW) {
fStorage.init(paint);
} else {
fStorage.init();
};
fPaint = fStorage.get();
} else {
fPaint = &paint;
}
}
operator GrPaint&&() && { return std::move(*fPaint); }
GrPaint& paint() { return *fPaint; }
private:
SkTLazy<GrPaint> fStorage;
GrPaint* fPaint;
};
#endif