michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef GrTextureAccess_DEFINED
michael@0: #define GrTextureAccess_DEFINED
michael@0: 
michael@0: #include "SkRefCnt.h"
michael@0: #include "SkShader.h"
michael@0: #include "SkTypes.h"
michael@0: 
michael@0: class GrTexture;
michael@0: 
michael@0: /**
michael@0:  * Represents the filtering and tile modes used to access a texture. It is mostly used with
michael@0:  * GrTextureAccess (defined below). Also, some of the texture cache methods require knowledge about
michael@0:  * filtering and tiling to perform a cache lookup. If it wasn't for this latter usage this would
michael@0:  * be folded into GrTextureAccess. The default is clamp tile modes and no filtering.
michael@0:  */
michael@0: class GrTextureParams {
michael@0: public:
michael@0:     GrTextureParams() {
michael@0:         this->reset();
michael@0:     }
michael@0: 
michael@0:     enum FilterMode {
michael@0:         kNone_FilterMode,
michael@0:         kBilerp_FilterMode,
michael@0:         kMipMap_FilterMode
michael@0:     };
michael@0: 
michael@0:     GrTextureParams(SkShader::TileMode tileXAndY, FilterMode filterMode) {
michael@0:         this->reset(tileXAndY, filterMode);
michael@0:     }
michael@0: 
michael@0:     GrTextureParams(const SkShader::TileMode tileModes[2], FilterMode filterMode) {
michael@0:         this->reset(tileModes, filterMode);
michael@0:     }
michael@0: 
michael@0:     GrTextureParams(const GrTextureParams& params) {
michael@0:         *this = params;
michael@0:     }
michael@0: 
michael@0:     GrTextureParams& operator= (const GrTextureParams& params) {
michael@0:         fTileModes[0] = params.fTileModes[0];
michael@0:         fTileModes[1] = params.fTileModes[1];
michael@0:         fFilterMode = params.fFilterMode;
michael@0:         return *this;
michael@0:     }
michael@0: 
michael@0:     void reset() {
michael@0:         this->reset(SkShader::kClamp_TileMode, kNone_FilterMode);
michael@0:     }
michael@0: 
michael@0:     void reset(SkShader::TileMode tileXAndY, FilterMode filterMode) {
michael@0:         fTileModes[0] = fTileModes[1] = tileXAndY;
michael@0:         fFilterMode = filterMode;
michael@0:     }
michael@0: 
michael@0:     void reset(const SkShader::TileMode tileModes[2], FilterMode filterMode) {
michael@0:         fTileModes[0] = tileModes[0];
michael@0:         fTileModes[1] = tileModes[1];
michael@0:         fFilterMode = filterMode;
michael@0:     }
michael@0: 
michael@0:     void setClampNoFilter() {
michael@0:         fTileModes[0] = fTileModes[1] = SkShader::kClamp_TileMode;
michael@0:         fFilterMode = kNone_FilterMode;
michael@0:     }
michael@0: 
michael@0:     void setClamp() {
michael@0:         fTileModes[0] = fTileModes[1] = SkShader::kClamp_TileMode;
michael@0:     }
michael@0: 
michael@0:     void setFilterMode(FilterMode filterMode) { fFilterMode = filterMode; }
michael@0: 
michael@0:     void setTileModeX(const SkShader::TileMode tm) { fTileModes[0] = tm; }
michael@0:     void setTileModeY(const SkShader::TileMode tm) { fTileModes[1] = tm; }
michael@0:     void setTileModeXAndY(const SkShader::TileMode tm) { fTileModes[0] = fTileModes[1] = tm; }
michael@0: 
michael@0:     SkShader::TileMode getTileModeX() const { return fTileModes[0]; }
michael@0: 
michael@0:     SkShader::TileMode getTileModeY() const { return fTileModes[1]; }
michael@0: 
michael@0:     bool isTiled() const {
michael@0:         return SkShader::kClamp_TileMode != fTileModes[0] ||
michael@0:                SkShader::kClamp_TileMode != fTileModes[1];
michael@0:     }
michael@0: 
michael@0:     FilterMode filterMode() const { return fFilterMode; }
michael@0: 
michael@0:     bool operator== (const GrTextureParams& other) const {
michael@0:         return fTileModes[0] == other.fTileModes[0] &&
michael@0:                fTileModes[1] == other.fTileModes[1] &&
michael@0:                fFilterMode == other.fFilterMode;
michael@0:     }
michael@0: 
michael@0:     bool operator!= (const GrTextureParams& other) const { return !(*this == other); }
michael@0: 
michael@0: private:
michael@0: 
michael@0:     SkShader::TileMode fTileModes[2];
michael@0:     FilterMode         fFilterMode;
michael@0: };
michael@0: 
michael@0: /** A class representing the swizzle access pattern for a texture. Note that if the texture is
michael@0:  *  an alpha-only texture then the alpha channel is substituted for other components. Any mangling
michael@0:  *  to handle the r,g,b->a conversions for alpha textures is automatically included in the stage
michael@0:  *  key. However, if a GrEffect uses different swizzles based on its input then it must
michael@0:  *  consider that variation in its key-generation.
michael@0:  */
michael@0: class GrTextureAccess : public SkNoncopyable {
michael@0: public:
michael@0:     /**
michael@0:      * A default GrTextureAccess must have reset() called on it in a GrEffect subclass's
michael@0:      * constructor if it will be accessible via GrEffect::textureAccess().
michael@0:      */
michael@0:     GrTextureAccess();
michael@0: 
michael@0:     /**
michael@0:      * Uses the default swizzle, "rgba".
michael@0:      */
michael@0:     GrTextureAccess(GrTexture*, const GrTextureParams&);
michael@0:     explicit GrTextureAccess(GrTexture*,
michael@0:                              GrTextureParams::FilterMode = GrTextureParams::kNone_FilterMode,
michael@0:                              SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode);
michael@0: 
michael@0:     /**
michael@0:      * swizzle must be a string between one and four (inclusive) characters containing only 'r',
michael@0:      * 'g', 'b',  and/or 'a'.
michael@0:      */
michael@0:     GrTextureAccess(GrTexture*, const char* swizzle, const GrTextureParams&);
michael@0:     GrTextureAccess(GrTexture*,
michael@0:                     const char* swizzle,
michael@0:                     GrTextureParams::FilterMode = GrTextureParams::kNone_FilterMode,
michael@0:                     SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode);
michael@0: 
michael@0:     void reset(GrTexture*, const GrTextureParams&);
michael@0:     void reset(GrTexture*,
michael@0:                GrTextureParams::FilterMode = GrTextureParams::kNone_FilterMode,
michael@0:                SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode);
michael@0:     void reset(GrTexture*, const char* swizzle, const GrTextureParams&);
michael@0:     void reset(GrTexture*,
michael@0:                const char* swizzle,
michael@0:                GrTextureParams::FilterMode = GrTextureParams::kNone_FilterMode,
michael@0:                SkShader::TileMode tileXAndY = SkShader::kClamp_TileMode);
michael@0: 
michael@0:     bool operator== (const GrTextureAccess& other) const {
michael@0: #ifdef SK_DEBUG
michael@0:         // below assumes all chars in fSwizzle are initialized even if string is < 4 chars long.
michael@0:         SkASSERT(memcmp(fSwizzle, other.fSwizzle, sizeof(fSwizzle)-1) ==
michael@0:                  strcmp(fSwizzle, other.fSwizzle));
michael@0: #endif
michael@0:         return fParams == other.fParams &&
michael@0:                (fTexture.get() == other.fTexture.get()) &&
michael@0:                (0 == memcmp(fSwizzle, other.fSwizzle, sizeof(fSwizzle)-1));
michael@0:     }
michael@0: 
michael@0:     bool operator!= (const GrTextureAccess& other) const { return !(*this == other); }
michael@0: 
michael@0:     GrTexture* getTexture() const { return fTexture.get(); }
michael@0: 
michael@0:     /**
michael@0:      * Returns a string representing the swizzle. The string is is null-terminated.
michael@0:      */
michael@0:     const char* getSwizzle() const { return fSwizzle; }
michael@0: 
michael@0:     /** Returns a mask indicating which components are referenced in the swizzle. The return
michael@0:         is a bitfield of GrColorComponentFlags. */
michael@0:     uint32_t swizzleMask() const { return fSwizzleMask; }
michael@0: 
michael@0:     const GrTextureParams& getParams() const { return fParams; }
michael@0: 
michael@0: private:
michael@0:     void setSwizzle(const char*);
michael@0: 
michael@0:     GrTextureParams         fParams;
michael@0:     SkAutoTUnref<GrTexture> fTexture;
michael@0:     uint32_t                fSwizzleMask;
michael@0:     char                    fSwizzle[5];
michael@0: 
michael@0:     typedef SkNoncopyable INHERITED;
michael@0: };
michael@0: 
michael@0: #endif