gecko/gfx/skia/include/gpu/GrTextureAccess.h
2012-09-18 15:41:36 -04:00

70 lines
2.0 KiB
C++

/*
* 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 GrTextureAccess_DEFINED
#define GrTextureAccess_DEFINED
#include "GrNoncopyable.h"
#include "SkRefCnt.h"
class GrTexture;
/** A class representing the swizzle access pattern for a texture. Note that if the texture is
* an alpha-only texture then the alpha channel is substituted for other components. Any mangling
* to handle the r,g,b->a conversions for alpha textures is automatically included in the stage
* key. However, if a GrCustomStage uses different swizzles based on its input then it must
* consider that variation in its key-generation.
*/
class GrTextureAccess : GrNoncopyable {
public:
/**
* A default GrTextureAccess must have reset() called on it in a GrCustomStage subclass's
* constructor if it will be accessible via GrCustomStage::textureAccess().
*/
GrTextureAccess();
/**
* swizzle must be a string between one and four (inclusive) characters containing only 'r',
* 'g', 'b', and/or 'a'.
*/
GrTextureAccess(GrTexture*, const char* swizzle);
/**
* Uses the default swizzle, "rgba".
*/
GrTextureAccess(GrTexture*);
void reset(GrTexture*, const char* swizzle);
void reset(GrTexture*);
GrTexture* getTexture() const { return fTexture.get(); }
/**
* Returns a string representing the swizzle. The string is is null-terminated.
*/
const char* getSwizzle() const { return fSwizzle; }
enum {
kR_SwizzleFlag = 0x1,
kG_SwizzleFlag = 0x2,
kB_SwizzleFlag = 0x4,
kA_SwizzleFlag = 0x8,
kRGB_SwizzleMask = (kR_SwizzleFlag | kG_SwizzleFlag | kB_SwizzleFlag),
};
/** Returns a mask indicating which components are referenced in the swizzle. */
uint32_t swizzleMask() const { return fSwizzleMask; }
private:
SkAutoTUnref<GrTexture> fTexture;
uint32_t fSwizzleMask;
char fSwizzle[5];
};
#endif