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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 GrTextureAccess_DEFINED
#define GrTextureAccess_DEFINED
#include "SkRefCnt.h"
#include "SkShader.h"
#include "SkTypes.h"
class GrTexture;
/**
* Represents the filtering and tile modes used to access a texture. It is mostly used with
* GrTextureAccess (defined below). Also, some of the texture cache methods require knowledge about
* filtering and tiling to perform a cache lookup. If it wasn't for this latter usage this would
* be folded into GrTextureAccess. The default is clamp tile modes and no filtering.
*/
class GrTextureParams {
public:
GrTextureParams() {
this->reset();
}
enum FilterMode {
kNone_FilterMode,
kBilerp_FilterMode,
kMipMap_FilterMode
};
GrTextureParams(SkShader::TileMode tileXAndY, FilterMode filterMode) {
this->reset(tileXAndY, filterMode);
}
GrTextureParams(const SkShader::TileMode tileModes[2], FilterMode filterMode) {
this->reset(tileModes, filterMode);
}
GrTextureParams(const GrTextureParams& params) {
*this = params;
}
GrTextureParams& operator= (const GrTextureParams& params) {
fTileModes[0] = params.fTileModes[0];
fTileModes[1] = params.fTileModes[1];
fFilterMode = params.fFilterMode;
return *this;
}
void reset() {
this->reset(SkShader::kClamp_TileMode, kNone_FilterMode);
}
void reset(SkShader::TileMode tileXAndY, FilterMode filterMode) {
fTileModes[0] = fTileModes[1] = tileXAndY;
fFilterMode = filterMode;
}
void reset(const SkShader::TileMode tileModes[2], FilterMode filterMode) {
fTileModes[0] = tileModes[0];
fTileModes[1] = tileModes[1];
fFilterMode = filterMode;
}
void setClampNoFilter() {
fTileModes[0] = fTileModes[1] = SkShader::kClamp_TileMode;
fFilterMode = kNone_FilterMode;
}
void setClamp() {
fTileModes[0] = fTileModes[1] = SkShader::kClamp_TileMode;
}
void setFilterMode(FilterMode filterMode) { fFilterMode = filterMode; }
void setTileModeX(const SkShader::TileMode tm) { fTileModes[0] = tm; }
void setTileModeY(const SkShader::TileMode tm) { fTileModes[1] = tm; }
void setTileModeXAndY(const SkShader::TileMode tm) { fTileModes[0] = fTileModes[1] = tm; }
SkShader::TileMode getTileModeX() const { return fTileModes[0]; }
SkShader::TileMode getTileModeY() const { return fTileModes[1]; }
bool isTiled() const {
return SkShader::kClamp_TileMode != fTileModes[0] ||
SkShader::kClamp_TileMode != fTileModes[1];
}
FilterMode filterMode() const { return fFilterMode; }
bool operator== (const GrTextureParams& other) const {
return fTileModes[0] == other.fTileModes[0] &&
fTileModes[1] == other.fTileModes[1] &&
fFilterMode == other.fFilterMode;
}
bool operator!= (const GrTextureParams& other) const { return !(*this == other); }
private:
SkShader::TileMode fTileModes[2];
FilterMode fFilterMode;
};
/** 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 GrEffect uses different swizzles based on its input then it must
* consider that variation in its key-generation.
*/
class GrTextureAccess : SkNoncopyable {
public:
/**
* A default GrTextureAccess must have reset() called on it in a GrEffect subclass's
* constructor if it will be accessible via GrEffect::textureAccess().
*/
GrTextureAccess();
/**
* Uses the default swizzle, "rgba".
*/
GrTextureAccess(GrTexture*, const GrTextureParams&);
explicit GrTextureAccess(GrTexture*,
GrTextureParams::FilterMode = GrTextureParams::kNone_FilterMode,
SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode);
/**
* swizzle must be a string between one and four (inclusive) characters containing only 'r',
* 'g', 'b', and/or 'a'.
*/
GrTextureAccess(GrTexture*, const char* swizzle, const GrTextureParams&);
GrTextureAccess(GrTexture*,
const char* swizzle,
GrTextureParams::FilterMode = GrTextureParams::kNone_FilterMode,
SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode);
void reset(GrTexture*, const GrTextureParams&);
void reset(GrTexture*,
GrTextureParams::FilterMode = GrTextureParams::kNone_FilterMode,
SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode);
void reset(GrTexture*, const char* swizzle, const GrTextureParams&);
void reset(GrTexture*,
const char* swizzle,
GrTextureParams::FilterMode = GrTextureParams::kNone_FilterMode,
SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode);
bool operator== (const GrTextureAccess& other) const {
#ifdef SK_DEBUG
// below assumes all chars in fSwizzle are initialized even if string is < 4 chars long.
SkASSERT(memcmp(fSwizzle, other.fSwizzle, sizeof(fSwizzle)-1) ==
strcmp(fSwizzle, other.fSwizzle));
#endif
return fParams == other.fParams &&
(fTexture.get() == other.fTexture.get()) &&
(0 == memcmp(fSwizzle, other.fSwizzle, sizeof(fSwizzle)-1));
}
bool operator!= (const GrTextureAccess& other) const { return !(*this == other); }
GrTexture* getTexture() const { return fTexture.get(); }
/**
* Returns a string representing the swizzle. The string is is null-terminated.
*/
const char* getSwizzle() const { return fSwizzle; }
/** Returns a mask indicating which components are referenced in the swizzle. The return
is a bitfield of GrColorComponentFlags. */
uint32_t swizzleMask() const { return fSwizzleMask; }
const GrTextureParams& getParams() const { return fParams; }
private:
void setSwizzle(const char*);
GrTextureParams fParams;
SkAutoTUnref<GrTexture> fTexture;
uint32_t fSwizzleMask;
char fSwizzle[5];
typedef SkNoncopyable INHERITED;
};
#endif