GrModulateAtlasCoverageEffect.h

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/*
 * Copyright 2021 Google LLC.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#ifndef GrGrModulateAtlasCoverageEffect_DEFINED
#define GrGrModulateAtlasCoverageEffect_DEFINED
 
#include "include/core/SkRect.h"
#include "include/gpu/GrTypes.h"
#include "src/gpu/ganesh/GrFragmentProcessor.h"
 
#include <memory>
 
class GrSurfaceProxyView;
class SkMatrix;
namespace skgpu { class KeyBuilder; }
struct GrShaderCaps;
 
// Multiplies 'inputFP' by the coverage value in an atlas, optionally inverting or clamping to 0.
class GrModulateAtlasCoverageEffect : public GrFragmentProcessor {
public:
    enum class Flags {
        kNone = 0,
        kInvertCoverage = 1 << 0,  // Return inputColor * (1 - atlasCoverage).
        kCheckBounds = 1 << 1  // Clamp atlasCoverage to 0 if outside the path's valid atlas bounds.
    };
 
    GR_DECL_BITFIELD_CLASS_OPS_FRIENDS(Flags);
 
    GrModulateAtlasCoverageEffect(Flags flags, std::unique_ptr<GrFragmentProcessor> inputFP,
                                  GrSurfaceProxyView atlasView, const SkMatrix& devToAtlasMatrix,
                                  const SkIRect& devIBounds);
 
    GrModulateAtlasCoverageEffect(const GrModulateAtlasCoverageEffect& that);
 
    const char* name() const override {
        return "GrModulateAtlasCoverageFP";
    }
 
    std::unique_ptr<GrFragmentProcessor> clone() const override {
        return std::make_unique<GrModulateAtlasCoverageEffect>(*this);
    }
 
private:
    void onAddToKey(const GrShaderCaps&, skgpu::KeyBuilder* b) const override;
 
    bool onIsEqual(const GrFragmentProcessor& that) const override {
        auto fp = that.cast<GrModulateAtlasCoverageEffect>();
        return fFlags == fp.fFlags && fBounds == fp.fBounds;
    }
    std::unique_ptr<ProgramImpl> onMakeProgramImpl() const override;
 
    const Flags fFlags;
    const SkIRect fBounds;
};
 
GR_MAKE_BITFIELD_CLASS_OPS(GrModulateAtlasCoverageEffect::Flags)
 
#endif