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
18class GrGpu;
19class GrRectanizer;
20class 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
32class GrPlot {
33public:
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
51private:
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
74typedef SkTInternalLList<GrPlot> GrPlotList;
75
76class GrAtlas {
77public:
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
133private:
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