1/*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef GrBicubicTextureEffect_DEFINED
9#define GrBicubicTextureEffect_DEFINED
10
11#include "GrSingleTextureEffect.h"
12#include "GrDrawEffect.h"
13#include "gl/GrGLEffect.h"
14#include "GrTBackendEffectFactory.h"
15
16class GrGLBicubicEffect;
17
18class GrBicubicEffect : public GrSingleTextureEffect {
19public:
20    enum {
21        kFilterTexelPad = 2, // Given a src rect in texels to be filtered, this number of
22                             // surrounding texels are needed by the kernel in x and y.
23    };
24    virtual ~GrBicubicEffect();
25
26    static const char* Name() { return "Bicubic"; }
27    const float* coefficients() const { return fCoefficients; }
28
29    typedef GrGLBicubicEffect GLEffect;
30
31    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
32    virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
33
34    /**
35     * Create a simple Mitchell filter effect.
36     */
37    static GrEffectRef* Create(GrTexture* tex) {
38        return Create(tex, gMitchellCoefficients);
39    }
40
41    /**
42     * Create a simple filter effect with custom bicubic coefficients.
43     */
44    static GrEffectRef* Create(GrTexture* tex, const SkScalar coefficients[16]) {
45        const SkShader::TileMode tm[] = { SkShader::kClamp_TileMode, SkShader::kClamp_TileMode };
46        return Create(tex, coefficients, MakeDivByTextureWHMatrix(tex), tm);
47    }
48
49    /**
50     * Create a Mitchell filter effect with specified texture matrix and x/y tile modes.
51     */
52    static GrEffectRef* Create(GrTexture* tex,
53                               const SkMatrix& matrix,
54                               SkShader::TileMode tileModes[2]) {
55        return Create(tex, gMitchellCoefficients, matrix, tileModes);
56    }
57
58    /**
59     * The most general Create method. This allows specification of the bicubic coefficients, the
60     * texture matrix, and the x/y tilemodes.
61     */
62    static GrEffectRef* Create(GrTexture* tex, const SkScalar coefficients[16],
63                               const SkMatrix& matrix,
64                               const SkShader::TileMode tileModes[2]) {
65        AutoEffectUnref effect(SkNEW_ARGS(GrBicubicEffect, (tex, coefficients, matrix, tileModes)));
66        return CreateEffectRef(effect);
67    }
68
69private:
70    GrBicubicEffect(GrTexture*, const SkScalar coefficients[16],
71                    const SkMatrix &matrix, const SkShader::TileMode tileModes[2]);
72    virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
73    float    fCoefficients[16];
74
75    GR_DECLARE_EFFECT_TEST;
76
77    static const SkScalar gMitchellCoefficients[16];
78
79    typedef GrSingleTextureEffect INHERITED;
80};
81
82#endif
83