skia/include/gpu/effects/GrConstColorProcessor.h

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrColorProcessor_DEFINED
#define GrColorProcessor_DEFINED

#include "GrFragmentProcessor.h"

class GrInvariantOutput;

/**
 * This is a simple GrFragmentProcessor that outputs a constant color. It may do one of the
 * following with its input color: ignore it, or multiply it by the constant color, multiply its
 * alpha by the constant color and ignore the input color's r, g, and b.
 */
class GrConstColorProcessor : public GrFragmentProcessor {
public:
    enum InputMode {
        kIgnore_InputMode,
        kModulateRGBA_InputMode,
        kModulateA_InputMode,

        kLastInputMode = kModulateA_InputMode
    };
    static const int kInputModeCnt = kLastInputMode + 1;

    static GrFragmentProcessor* Create(GrColor color, InputMode mode) {
        return SkNEW_ARGS(GrConstColorProcessor, (color, mode));
    }

    ~GrConstColorProcessor() override {}

    const char* name() const override { return "Color"; }

    void getGLProcessorKey(const GrGLSLCaps&, GrProcessorKeyBuilder*) const override;

    GrGLFragmentProcessor* createGLInstance() const override;

    GrColor color() const { return fColor; }

    InputMode inputMode() const { return fMode; }

private:
    GrConstColorProcessor(GrColor color, InputMode mode) : fColor(color), fMode(mode) {
        this->initClassID<GrConstColorProcessor>();
    }

    bool onIsEqual(const GrFragmentProcessor&) const override;

    void onComputeInvariantOutput(GrInvariantOutput* inout) const override;

    GR_DECLARE_FRAGMENT_PROCESSOR_TEST;

    GrColor     fColor;
    InputMode   fMode;

    typedef GrFragmentProcessor INHERITED;
};

#endif