skia2/include/gpu/effects/GrPorterDuffXferProcessor.h

/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrPorterDuffXferProcessor_DEFINED
#define GrPorterDuffXferProcessor_DEFINED

#include "GrTypes.h"
#include "GrXferProcessor.h"
#include "SkBlendMode.h"

class GrProcOptInfo;

class GrPorterDuffXPFactory : public GrXPFactory {
public:
    static sk_sp<GrXPFactory> Make(SkBlendMode mode);

    void getInvariantBlendedColor(const GrProcOptInfo& colorPOI,
                                  GrXPFactory::InvariantBlendedColor*) const override;


    /** Because src-over is so common we special case it for performance reasons. If this returns
        null then the SimpleSrcOverXP() below should be used. */
    static GrXferProcessor* CreateSrcOverXferProcessor(const GrCaps& caps,
                                                       const GrPipelineOptimizations& optimizations,
                                                       bool hasMixedSamples,
                                                       const GrXferProcessor::DstTexture*);
    /** This XP implements non-LCD src-over using hw blend with no optimizations. It is returned
        by reference because it is global and its ref-cnting methods are not thread safe. */
    static const GrXferProcessor& SimpleSrcOverXP();

    static inline void SrcOverInvariantBlendedColor(
                                                GrColor inputColor,
                                                GrColorComponentFlags validColorFlags,
                                                bool isOpaque,
                                                GrXPFactory::InvariantBlendedColor* blendedColor) {
        if (!isOpaque) {
            blendedColor->fWillBlendWithDst = true;
            blendedColor->fKnownColorFlags = kNone_GrColorComponentFlags;
            return;
        }
        blendedColor->fWillBlendWithDst = false;

        blendedColor->fKnownColor = inputColor;
        blendedColor->fKnownColorFlags = validColorFlags;
    }

    static bool SrcOverWillNeedDstTexture(const GrCaps&, const GrPipelineOptimizations&);

private:
    GrPorterDuffXPFactory(SkBlendMode);

    GrXferProcessor* onCreateXferProcessor(const GrCaps& caps,
                                           const GrPipelineOptimizations& optimizations,
                                           bool hasMixedSamples,
                                           const DstTexture*) const override;

    bool onWillReadDstColor(const GrCaps&, const GrPipelineOptimizations&) const override;

    bool onIsEqual(const GrXPFactory& xpfBase) const override {
        const GrPorterDuffXPFactory& xpf = xpfBase.cast<GrPorterDuffXPFactory>();
        return fXfermode == xpf.fXfermode;
    }

    GR_DECLARE_XP_FACTORY_TEST;
    static void TestGetXPOutputTypes(const GrXferProcessor*, int* outPrimary, int* outSecondary);

    SkBlendMode fXfermode;

    friend class GrPorterDuffTest; // for TestGetXPOutputTypes()
    typedef GrXPFactory INHERITED;
};

#endif