6d003d1ddc
Review URL: https://codereview.appspot.com/6494114 git-svn-id: http://skia.googlecode.com/svn/trunk@5485 2bbb7eff-a529-9590-31e7-b0007b416f81
70 lines
2.0 KiB
C++
70 lines
2.0 KiB
C++
/*
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* Copyright 2012 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef GrTextureAccess_DEFINED
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#define GrTextureAccess_DEFINED
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#include "GrNoncopyable.h"
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#include "SkRefCnt.h"
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class GrTexture;
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/** A class representing the swizzle access pattern for a texture. Note that if the texture is
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* an alpha-only texture then the alpha channel is substituted for other components. Any mangling
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* to handle the r,g,b->a conversions for alpha textures is automatically included in the stage
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* key. However, if a GrCustomStage uses different swizzles based on its input then it must
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* consider that variation in its key-generation.
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*/
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class GrTextureAccess : GrNoncopyable {
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public:
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/**
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* A default GrTextureAccess must have reset() called on it in a GrCustomStage subclass's
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* constructor if it will be accessible via GrCustomStage::textureAccess().
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*/
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GrTextureAccess();
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/**
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* swizzle must be a string between one and four (inclusive) characters containing only 'r',
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* 'g', 'b', and/or 'a'.
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*/
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GrTextureAccess(GrTexture*, const char* swizzle);
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/**
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* Uses the default swizzle, "rgba".
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*/
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GrTextureAccess(GrTexture*);
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void reset(GrTexture*, const char* swizzle);
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void reset(GrTexture*);
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GrTexture* getTexture() const { return fTexture.get(); }
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/**
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* Returns a string representing the swizzle. The string is is null-terminated.
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*/
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const char* getSwizzle() const { return fSwizzle; }
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enum {
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kR_SwizzleFlag = 0x1,
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kG_SwizzleFlag = 0x2,
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kB_SwizzleFlag = 0x4,
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kA_SwizzleFlag = 0x8,
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kRGB_SwizzleMask = (kR_SwizzleFlag | kG_SwizzleFlag | kB_SwizzleFlag),
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};
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/** Returns a mask indicating which components are referenced in the swizzle. */
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uint32_t swizzleMask() const { return fSwizzleMask; }
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private:
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SkAutoTUnref<GrTexture> fTexture;
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uint32_t fSwizzleMask;
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char fSwizzle[5];
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};
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#endif
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