GrCoordTransform.h

/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef GrCoordTransform_DEFINED
#define GrCoordTransform_DEFINED

#include "GrProcessor.h"
#include "SkMatrix.h"
#include "GrTexture.h"
#include "GrTypes.h"
#include "GrShaderVar.h"

enum GrCoordSet {
    kLocal_GrCoordSet,

    kDevice_GrCoordSet,
};

class GrCoordTransform : SkNoncopyable {
public:
    GrCoordTransform() : fSourceCoords(kLocal_GrCoordSet) { SkDEBUGCODE(fInProcessor = false); }

    GrCoordTransform(GrCoordSet sourceCoords,
                     const GrTexture* texture,
                     GrTextureParams::FilterMode filter) {
        SkASSERT(texture);
        SkDEBUGCODE(fInProcessor = false);
        this->reset(sourceCoords, texture, filter);
    }

    GrCoordTransform(GrCoordSet sourceCoords, const SkMatrix& m,
                     const GrTexture* texture, GrTextureParams::FilterMode filter) {
        SkDEBUGCODE(fInProcessor = false);
        SkASSERT(texture);
        this->reset(sourceCoords, m, texture, filter);
    }

    GrCoordTransform(GrCoordSet sourceCoords, const SkMatrix& m,
                     GrSLPrecision precision = kDefault_GrSLPrecision) {
        SkDEBUGCODE(fInProcessor = false);
        this->reset(sourceCoords, m, precision);
    }

    void reset(GrCoordSet sourceCoords, const GrTexture* texture,
               GrTextureParams::FilterMode filter) {
        SkASSERT(!fInProcessor);
        SkASSERT(texture);
        this->reset(sourceCoords, MakeDivByTextureWHMatrix(texture), texture, filter);
    }

    void reset(GrCoordSet, const SkMatrix&, const GrTexture*, GrTextureParams::FilterMode filter);
    void reset(GrCoordSet sourceCoords, const SkMatrix& m,
               GrSLPrecision precision = kDefault_GrSLPrecision);

    GrCoordTransform& operator= (const GrCoordTransform& that) {
        SkASSERT(!fInProcessor);
        fSourceCoords = that.fSourceCoords;
        fMatrix = that.fMatrix;
        fReverseY = that.fReverseY;
        fPrecision = that.fPrecision;
        return *this;
    }

    SkMatrix* accessMatrix() {
        SkASSERT(!fInProcessor);
        return &fMatrix;
    }

    bool operator==(const GrCoordTransform& that) const {
        return fSourceCoords == that.fSourceCoords &&
               fMatrix.cheapEqualTo(that.fMatrix) &&
               fReverseY == that.fReverseY &&
               fPrecision == that.fPrecision;
    }

    bool operator!=(const GrCoordTransform& that) const { return !(*this == that); }

    GrCoordSet sourceCoords() const { return fSourceCoords; }
    const SkMatrix& getMatrix() const { return fMatrix; }
    bool reverseY() const { return fReverseY; }
    GrSLPrecision precision() const { return fPrecision; }

    static inline SkMatrix MakeDivByTextureWHMatrix(const GrTexture* texture) {
        SkASSERT(texture);
        SkMatrix mat;
        (void)mat.setIDiv(texture->width(), texture->height());
        return mat;
    }

private:
    GrCoordSet              fSourceCoords;
    SkMatrix                fMatrix;
    bool                    fReverseY;
    GrSLPrecision           fPrecision;
    typedef SkNoncopyable INHERITED;

#ifdef SK_DEBUG
public:
    void setInProcessor() const { fInProcessor = true; }
private:
    mutable bool fInProcessor;
#endif
};

#endif