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      1 
      2 /*
      3  * Copyright 2011 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 #ifndef GrTexture_DEFINED
     10 #define GrTexture_DEFINED
     11 
     12 #include "GrSurface.h"
     13 
     14 class GrRenderTarget;
     15 class GrResourceKey;
     16 class GrTextureParams;
     17 
     18 class GrTexture : public GrSurface {
     19 
     20 public:
     21     SK_DECLARE_INST_COUNT(GrTexture)
     22     // from GrResource
     23     /**
     24      * Informational texture flags
     25      */
     26     enum FlagBits {
     27         kFirstBit = (kLastPublic_GrTextureFlagBit << 1),
     28 
     29         /**
     30          * This texture should be returned to the texture cache when
     31          * it is no longer reffed
     32          */
     33         kReturnToCache_FlagBit        = kFirstBit,
     34     };
     35 
     36     void setFlag(GrTextureFlags flags) {
     37         fDesc.fFlags = fDesc.fFlags | flags;
     38     }
     39     void resetFlag(GrTextureFlags flags) {
     40         fDesc.fFlags = fDesc.fFlags & ~flags;
     41     }
     42     bool isSetFlag(GrTextureFlags flags) const {
     43         return 0 != (fDesc.fFlags & flags);
     44     }
     45 
     46     /**
     47      *  Approximate number of bytes used by the texture
     48      */
     49     virtual size_t sizeInBytes() const SK_OVERRIDE {
     50         return (size_t) fDesc.fWidth *
     51                         fDesc.fHeight *
     52                         GrBytesPerPixel(fDesc.fConfig);
     53     }
     54 
     55     // GrSurface overrides
     56     virtual bool readPixels(int left, int top, int width, int height,
     57                             GrPixelConfig config,
     58                             void* buffer,
     59                             size_t rowBytes = 0,
     60                             uint32_t pixelOpsFlags = 0) SK_OVERRIDE;
     61 
     62     virtual void writePixels(int left, int top, int width, int height,
     63                              GrPixelConfig config,
     64                              const void* buffer,
     65                              size_t rowBytes = 0,
     66                              uint32_t pixelOpsFlags = 0) SK_OVERRIDE;
     67 
     68     /**
     69      * @return this texture
     70      */
     71     virtual GrTexture* asTexture() SK_OVERRIDE { return this; }
     72     virtual const GrTexture* asTexture() const SK_OVERRIDE { return this; }
     73 
     74     /**
     75      * Retrieves the render target underlying this texture that can be passed to
     76      * GrGpu::setRenderTarget().
     77      *
     78      * @return    handle to render target or NULL if the texture is not a
     79      *            render target
     80      */
     81     virtual GrRenderTarget* asRenderTarget() SK_OVERRIDE {
     82         return fRenderTarget;
     83     }
     84     virtual const GrRenderTarget* asRenderTarget() const SK_OVERRIDE {
     85         return fRenderTarget;
     86     }
     87 
     88     // GrTexture
     89     /**
     90      * Convert from texels to normalized texture coords for POT textures
     91      * only.
     92      */
     93     GrFixed normalizeFixedX(GrFixed x) const {
     94         GrAssert(GrIsPow2(fDesc.fWidth));
     95         return x >> fShiftFixedX;
     96     }
     97     GrFixed normalizeFixedY(GrFixed y) const {
     98         GrAssert(GrIsPow2(fDesc.fHeight));
     99         return y >> fShiftFixedY;
    100     }
    101 
    102     /**
    103      * Removes the reference on the associated GrRenderTarget held by this
    104      * texture. Afterwards asRenderTarget() will return NULL. The
    105      * GrRenderTarget survives the release if another ref is held on it.
    106      */
    107     void releaseRenderTarget();
    108 
    109     /**
    110      *  Return the native ID or handle to the texture, depending on the
    111      *  platform. e.g. on OpenGL, return the texture ID.
    112      */
    113     virtual GrBackendObject getTextureHandle() const = 0;
    114 
    115     /**
    116      *  Call this when the state of the native API texture object is
    117      *  altered directly, without being tracked by skia.
    118      */
    119     virtual void invalidateCachedState() = 0;
    120 
    121 #if GR_DEBUG
    122     void validate() const {
    123         this->INHERITED::validate();
    124 
    125         this->validateDesc();
    126     }
    127 #else
    128     void validate() const {}
    129 #endif
    130     static GrResourceKey ComputeKey(const GrGpu* gpu,
    131                                     const GrTextureParams* params,
    132                                     const GrTextureDesc& desc,
    133                                     const GrCacheID& cacheID);
    134     static GrResourceKey ComputeScratchKey(const GrTextureDesc& desc);
    135     static bool NeedsResizing(const GrResourceKey& key);
    136     static bool NeedsFiltering(const GrResourceKey& key);
    137 
    138 protected:
    139     GrRenderTarget* fRenderTarget; // texture refs its rt representation
    140                                    // base class cons sets to NULL
    141                                    // subclass cons can create and set
    142 
    143     GrTexture(GrGpu* gpu, bool isWrapped, const GrTextureDesc& desc, GrSurfaceOrigin origin)
    144     : INHERITED(gpu, isWrapped, desc, origin)
    145     , fRenderTarget(NULL) {
    146 
    147         // only make sense if alloc size is pow2
    148         fShiftFixedX = 31 - SkCLZ(fDesc.fWidth);
    149         fShiftFixedY = 31 - SkCLZ(fDesc.fHeight);
    150     }
    151 
    152     // GrResource overrides
    153     virtual void onRelease() SK_OVERRIDE;
    154     virtual void onAbandon() SK_OVERRIDE;
    155 
    156     void validateDesc() const;
    157 
    158 private:
    159     // these two shift a fixed-point value into normalized coordinates
    160     // for this texture if the texture is power of two sized.
    161     int                 fShiftFixedX;
    162     int                 fShiftFixedY;
    163 
    164     virtual void internal_dispose() const SK_OVERRIDE;
    165 
    166     typedef GrSurface INHERITED;
    167 };
    168 
    169 #endif
    170