GrFragmentProcessor.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 GrFragmentProcessor_DEFINED
#define GrFragmentProcessor_DEFINED

#include "GrProcessor.h"

class GrCoordTransform;
class GrGLSLCaps;
class GrGLSLFragmentProcessor;
class GrInvariantOutput;
class GrProcessorKeyBuilder;

class GrFragmentProcessor : public GrProcessor {
public:
    static sk_sp<GrFragmentProcessor> MulOutputByInputAlpha(sk_sp<GrFragmentProcessor>);

    static sk_sp<GrFragmentProcessor> MulOutputByInputUnpremulColor(sk_sp<GrFragmentProcessor>);

    static sk_sp<GrFragmentProcessor> OverrideInput(sk_sp<GrFragmentProcessor>, GrColor);

    static sk_sp<GrFragmentProcessor> PremulInput(sk_sp<GrFragmentProcessor>);

    static sk_sp<GrFragmentProcessor> RunInSeries(sk_sp<GrFragmentProcessor>*, int cnt);

    GrFragmentProcessor()
        : INHERITED()
        , fUsesDistanceVectorField(false)
        , fUsesLocalCoords(false)
        , fNumTexturesExclChildren(0)
        , fNumBuffersExclChildren(0)
        , fNumTransformsExclChildren(0) {}

    ~GrFragmentProcessor() override;

    GrGLSLFragmentProcessor* createGLSLInstance() const;

    void getGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const {
        this->onGetGLSLProcessorKey(caps, b);
        for (int i = 0; i < fChildProcessors.count(); ++i) {
            fChildProcessors[i]->getGLSLProcessorKey(caps, b);
        }
    }

    int numTexturesExclChildren() const { return fNumTexturesExclChildren; }

    int numBuffersExclChildren() const { return fNumBuffersExclChildren; }

    int numTransformsExclChildren() const { return fNumTransformsExclChildren; }

    int numTransforms() const { return fCoordTransforms.count(); }

    const GrCoordTransform& coordTransform(int index) const { return *fCoordTransforms[index]; }

    const SkTArray<const GrCoordTransform*, true>& coordTransforms() const {
        return fCoordTransforms;
    }

    void gatherCoordTransforms(SkTArray<const GrCoordTransform*, true>* outTransforms) const {
        if (!fCoordTransforms.empty()) {
            outTransforms->push_back_n(fCoordTransforms.count(), fCoordTransforms.begin());
        }
    }

    int numChildProcessors() const { return fChildProcessors.count(); }

    const GrFragmentProcessor& childProcessor(int index) const { return *fChildProcessors[index]; }

    bool usesLocalCoords() const { return fUsesLocalCoords; }

    bool usesDistanceVectorField() const { return fUsesDistanceVectorField; }

    bool isEqual(const GrFragmentProcessor& that, bool ignoreCoordTransforms) const;

    void computeInvariantOutput(GrInvariantOutput* inout) const {
        this->onComputeInvariantOutput(inout);
    }

protected:
    void addTextureAccess(const GrTextureAccess* textureAccess) override;
    void addBufferAccess(const GrBufferAccess*) override;

    void addCoordTransform(const GrCoordTransform*);

    int registerChildProcessor(sk_sp<GrFragmentProcessor> child);

    virtual void onComputeInvariantOutput(GrInvariantOutput* inout) const = 0;

    /* Sub-classes should set this to true in their constructors if they need access to a distance
     * vector field to the nearest edge
     */
    bool fUsesDistanceVectorField;

private:
    void notifyRefCntIsZero() const final;

    virtual GrGLSLFragmentProcessor* onCreateGLSLInstance() const = 0;

    virtual void onGetGLSLProcessorKey(const GrGLSLCaps& caps,
                                       GrProcessorKeyBuilder* b) const = 0;

    virtual bool onIsEqual(const GrFragmentProcessor&) const = 0;

    bool hasSameTransforms(const GrFragmentProcessor&) const;

    bool                                       fUsesLocalCoords;

    SkSTArray<4, const GrCoordTransform*, true> fCoordTransforms;
    int                                         fNumTexturesExclChildren;
    int                                         fNumBuffersExclChildren;
    int                                         fNumTransformsExclChildren;

    SkSTArray<1, GrFragmentProcessor*, true>    fChildProcessors;

    typedef GrProcessor INHERITED;
};

#endif