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      1 
      2 /*
      3  * Copyright 2010 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 GrAtlas_DEFINED
     10 #define GrAtlas_DEFINED
     11 
     12 
     13 #include "GrTexture.h"
     14 #include "GrDrawTarget.h"
     15 #include "SkPoint.h"
     16 #include "SkTInternalLList.h"
     17 
     18 class GrGpu;
     19 class GrRectanizer;
     20 class GrAtlas;
     21 
     22 // The backing GrTexture for a set of GrAtlases is broken into a spatial grid of GrPlots. When
     23 // a GrAtlas needs space on the texture, it requests a GrPlot. Each GrAtlas can claim one
     24 // or more GrPlots. The GrPlots keep track of subimage placement via their GrRectanizer. Once a
     25 // GrPlot is "full" (i.e. there is no room for the new subimage according to the GrRectanizer), the
     26 // GrAtlas can request a new GrPlot via GrAtlas::addToAtlas().
     27 //
     28 // If all GrPlots are allocated, the replacement strategy is up to the client. The drawToken is
     29 // available to ensure that all draw calls are finished for that particular GrPlot.
     30 // GrAtlas::removeUnusedPlots() will free up any finished plots for a given GrAtlas.
     31 
     32 class GrPlot {
     33 public:
     34     SK_DECLARE_INTERNAL_LLIST_INTERFACE(GrPlot);
     35 
     36     // This returns a plot ID unique to each plot in a given GrAtlas. They are
     37     // consecutive and start at 0.
     38     int id() const { return fID; }
     39 
     40     GrTexture* texture() const { return fTexture; }
     41 
     42     bool addSubImage(int width, int height, const void*, SkIPoint16*);
     43 
     44     GrDrawTarget::DrawToken drawToken() const { return fDrawToken; }
     45     void setDrawToken(GrDrawTarget::DrawToken draw) { fDrawToken = draw; }
     46 
     47     void uploadToTexture();
     48 
     49     void resetRects();
     50 
     51 private:
     52     GrPlot();
     53     ~GrPlot(); // does not try to delete the fNext field
     54     void init(GrAtlas* atlas, int id, int offX, int offY, int width, int height, size_t bpp,
     55               bool batchUploads);
     56 
     57     // for recycling
     58     GrDrawTarget::DrawToken fDrawToken;
     59 
     60     int                     fID;
     61     unsigned char*          fPlotData;
     62     GrTexture*              fTexture;
     63     GrRectanizer*           fRects;
     64     GrAtlas*                fAtlas;
     65     SkIPoint16              fOffset;        // the offset of the plot in the backing texture
     66     size_t                  fBytesPerPixel;
     67     SkIRect                 fDirtyRect;
     68     bool                    fDirty;
     69     bool                    fBatchUploads;
     70 
     71     friend class GrAtlas;
     72 };
     73 
     74 typedef SkTInternalLList<GrPlot> GrPlotList;
     75 
     76 class GrAtlas {
     77 public:
     78     // This class allows each client to independently track the GrPlots in
     79     // which its data is stored.
     80     class ClientPlotUsage {
     81     public:
     82         bool isEmpty() const { return 0 == fPlots.count(); }
     83 
     84 #ifdef SK_DEBUG
     85         bool contains(const GrPlot* plot) const {
     86             return fPlots.contains(const_cast<GrPlot*>(plot));
     87         }
     88 #endif
     89 
     90     private:
     91         SkTDArray<GrPlot*> fPlots;
     92 
     93         friend class GrAtlas;
     94     };
     95 
     96     GrAtlas(GrGpu*, GrPixelConfig, GrSurfaceFlags flags,
     97             const SkISize& backingTextureSize,
     98             int numPlotsX, int numPlotsY, bool batchUploads);
     99     ~GrAtlas();
    100 
    101     // Adds a width x height subimage to the atlas. Upon success it returns
    102     // the containing GrPlot and absolute location in the backing texture.
    103     // NULL is returned if the subimage cannot fit in the atlas.
    104     // If provided, the image data will either be immediately uploaded or
    105     // written to the CPU-side backing bitmap.
    106     GrPlot* addToAtlas(ClientPlotUsage*, int width, int height, const void* image, SkIPoint16* loc);
    107 
    108     // remove reference to this plot
    109     static void RemovePlot(ClientPlotUsage* usage, const GrPlot* plot);
    110 
    111     // get a plot that's not being used by the current draw
    112     // this allows us to overwrite this plot without flushing
    113     GrPlot* getUnusedPlot();
    114 
    115     GrTexture* getTexture() const {
    116         return fTexture;
    117     }
    118 
    119     void uploadPlotsToTexture();
    120 
    121     enum IterOrder {
    122         kLRUFirst_IterOrder,
    123         kMRUFirst_IterOrder
    124     };
    125 
    126     typedef GrPlotList::Iter PlotIter;
    127     GrPlot* iterInit(PlotIter* iter, IterOrder order) {
    128         return iter->init(fPlotList, kLRUFirst_IterOrder == order
    129                                                        ? GrPlotList::Iter::kTail_IterStart
    130                                                        : GrPlotList::Iter::kHead_IterStart);
    131     }
    132 
    133 private:
    134     void makeMRU(GrPlot* plot);
    135 
    136     GrGpu*         fGpu;
    137     GrPixelConfig  fPixelConfig;
    138     GrSurfaceFlags fFlags;
    139     GrTexture*     fTexture;
    140     SkISize        fBackingTextureSize;
    141     int            fNumPlotsX;
    142     int            fNumPlotsY;
    143     bool           fBatchUploads;
    144 
    145     // allocated array of GrPlots
    146     GrPlot*       fPlotArray;
    147     // LRU list of GrPlots (MRU at head - LRU at tail)
    148     GrPlotList    fPlotList;
    149 };
    150 
    151 #endif
    152