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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrGradientEffects_DEFINED
#define GrGradientEffects_DEFINED
#include "GrSingleTextureEffect.h"
#include "GrTypes.h"
#include "GrScalar.h"
#include "SkShader.h"
/*
* The intepretation of the texture matrix depends on the sample mode. The
* texture matrix is applied both when the texture coordinates are explicit
* and when vertex positions are used as texture coordinates. In the latter
* case the texture matrix is applied to the pre-view-matrix position
* values.
*
* Normal SampleMode
* The post-matrix texture coordinates are in normalize space with (0,0) at
* the top-left and (1,1) at the bottom right.
* RadialGradient
* The matrix specifies the radial gradient parameters.
* (0,0) in the post-matrix space is center of the radial gradient.
* Radial2Gradient
* Matrix transforms to space where first circle is centered at the
* origin. The second circle will be centered (x, 0) where x may be
* 0 and is provided by setRadial2Params. The post-matrix space is
* normalized such that 1 is the second radius - first radius.
* SweepGradient
* The angle from the origin of texture coordinates in post-matrix space
* determines the gradient value.
*/
// Base class for Gr gradient effects
class GrGradientEffect : public GrCustomStage {
public:
GrGradientEffect(GrTexture* texture);
GrGradientEffect(GrContext* ctx, const SkShader& shader);
virtual ~GrGradientEffect();
unsigned int numTextures() const;
GrTexture* texture(unsigned int index) const;
bool useTexture() const { return fUseTexture; }
private:
GrTexture* fTexture;
bool fUseTexture;
typedef GrCustomStage INHERITED;
};
class GrGLLinearGradient;
class GrLinearGradient : public GrGradientEffect {
public:
GrLinearGradient(GrTexture* texture);
GrLinearGradient(GrContext* ctx, const SkShader& shader);
virtual ~GrLinearGradient();
static const char* Name() { return "Linear Gradient"; }
virtual const GrProgramStageFactory& getFactory() const SK_OVERRIDE;
typedef GrGLLinearGradient GLProgramStage;
private:
typedef GrGradientEffect INHERITED;
};
class GrGLRadialGradient;
class GrRadialGradient : public GrGradientEffect {
public:
GrRadialGradient(GrTexture* texture);
GrRadialGradient(GrContext* ctx, const SkShader& shader);
virtual ~GrRadialGradient();
static const char* Name() { return "Radial Gradient"; }
virtual const GrProgramStageFactory& getFactory() const SK_OVERRIDE;
typedef GrGLRadialGradient GLProgramStage;
private:
typedef GrGradientEffect INHERITED;
};
class GrGLRadial2Gradient;
class GrRadial2Gradient : public GrGradientEffect {
public:
GrRadial2Gradient(GrTexture* texture, GrScalar center, GrScalar radius, bool posRoot);
GrRadial2Gradient(GrContext* ctx, const SkShader& shader);
virtual ~GrRadial2Gradient();
static const char* Name() { return "Two-Point Radial Gradient"; }
virtual const GrProgramStageFactory& getFactory() const SK_OVERRIDE;
virtual bool isEqual(const GrCustomStage&) const SK_OVERRIDE;
// The radial gradient parameters can collapse to a linear (instead of quadratic) equation.
bool isDegenerate() const { return GR_Scalar1 == fCenterX1; }
GrScalar center() const { return fCenterX1; }
GrScalar radius() const { return fRadius0; }
bool isPosRoot() const { return SkToBool(fPosRoot); }
typedef GrGLRadial2Gradient GLProgramStage;
private:
// @{
// Cache of values - these can change arbitrarily, EXCEPT
// we shouldn't change between degenerate and non-degenerate?!
GrScalar fCenterX1;
GrScalar fRadius0;
SkBool8 fPosRoot;
// @}
typedef GrGradientEffect INHERITED;
};
class GrGLConical2Gradient;
class GrConical2Gradient : public GrGradientEffect {
public:
GrConical2Gradient(GrTexture* texture, GrScalar center, GrScalar radius, GrScalar diffRadius);
GrConical2Gradient(GrContext* ctx, const SkShader& shader);
virtual ~GrConical2Gradient();
static const char* Name() { return "Two-Point Conical Gradient"; }
virtual const GrProgramStageFactory& getFactory() const SK_OVERRIDE;
virtual bool isEqual(const GrCustomStage&) const SK_OVERRIDE;
// The radial gradient parameters can collapse to a linear (instead of quadratic) equation.
bool isDegenerate() const { return SkScalarAbs(fDiffRadius) == SkScalarAbs(fCenterX1); }
GrScalar center() const { return fCenterX1; }
GrScalar diffRadius() const { return fDiffRadius; }
GrScalar radius() const { return fRadius0; }
typedef GrGLConical2Gradient GLProgramStage;
private:
// @{
// Cache of values - these can change arbitrarily, EXCEPT
// we shouldn't change between degenerate and non-degenerate?!
GrScalar fCenterX1;
GrScalar fRadius0;
GrScalar fDiffRadius;
// @}
typedef GrGradientEffect INHERITED;
};
class GrGLSweepGradient;
class GrSweepGradient : public GrGradientEffect {
public:
GrSweepGradient(GrTexture* texture);
GrSweepGradient(GrContext* ctx, const SkShader& shader);
virtual ~GrSweepGradient();
static const char* Name() { return "Sweep Gradient"; }
virtual const GrProgramStageFactory& getFactory() const SK_OVERRIDE;
typedef GrGLSweepGradient GLProgramStage;
protected:
typedef GrGradientEffect INHERITED;
};
#endif
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