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* Copyright 2010 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef GrAtlas_DEFINED
#define GrAtlas_DEFINED
#include "GrTexture.h"
#include "GrDrawTarget.h"
#include "SkPoint.h"
#include "SkTInternalLList.h"
class GrGpu;
class GrRectanizer;
class GrAtlas;
// The backing GrTexture for a set of GrAtlases is broken into a spatial grid of GrPlots. When
// a GrAtlas needs space on the texture, it requests a GrPlot. Each GrAtlas can claim one
// or more GrPlots. The GrPlots keep track of subimage placement via their GrRectanizer. Once a
// GrPlot is "full" (i.e. there is no room for the new subimage according to the GrRectanizer), the
// GrAtlas can request a new GrPlot via GrAtlas::addToAtlas().
// If all GrPlots are allocated, the replacement strategy is up to the client. The drawToken is
// available to ensure that all draw calls are finished for that particular GrPlot.
// GrAtlas::removeUnusedPlots() will free up any finished plots for a given GrAtlas.
class GrPlot {
// This returns a plot ID unique to each plot in a given GrAtlas. They are
// consecutive and start at 0.
int id() const { return fID; }
GrTexture* texture() const { return fTexture; }
bool addSubImage(int width, int height, const void*, SkIPoint16*);
GrDrawTarget::DrawToken drawToken() const { return fDrawToken; }
void setDrawToken(GrDrawTarget::DrawToken draw) { fDrawToken = draw; }
void uploadToTexture();
void resetRects();
~GrPlot(); // does not try to delete the fNext field
void init(GrAtlas* atlas, int id, int offX, int offY, int width, int height, size_t bpp,
bool batchUploads);
// for recycling
GrDrawTarget::DrawToken fDrawToken;
int fID;
unsigned char* fPlotData;
GrTexture* fTexture;
GrRectanizer* fRects;
GrAtlas* fAtlas;
SkIPoint16 fOffset; // the offset of the plot in the backing texture
size_t fBytesPerPixel;
SkIRect fDirtyRect;
bool fDirty;
bool fBatchUploads;
friend class GrAtlas;
typedef SkTInternalLList<GrPlot> GrPlotList;
class GrAtlas {
// This class allows each client to independently track the GrPlots in
// which its data is stored.
class ClientPlotUsage {
bool isEmpty() const { return 0 == fPlots.count(); }
#ifdef SK_DEBUG
bool contains(const GrPlot* plot) const {
return fPlots.contains(const_cast<GrPlot*>(plot));
SkTDArray<GrPlot*> fPlots;
friend class GrAtlas;
GrAtlas(GrGpu*, GrPixelConfig, GrSurfaceFlags flags,
const SkISize& backingTextureSize,
int numPlotsX, int numPlotsY, bool batchUploads);
// Adds a width x height subimage to the atlas. Upon success it returns
// the containing GrPlot and absolute location in the backing texture.
// NULL is returned if the subimage cannot fit in the atlas.
// If provided, the image data will either be immediately uploaded or
// written to the CPU-side backing bitmap.
GrPlot* addToAtlas(ClientPlotUsage*, int width, int height, const void* image, SkIPoint16* loc);
// remove reference to this plot
static void RemovePlot(ClientPlotUsage* usage, const GrPlot* plot);
// get a plot that's not being used by the current draw
// this allows us to overwrite this plot without flushing
GrPlot* getUnusedPlot();
GrTexture* getTexture() const {
return fTexture;
void uploadPlotsToTexture();
enum IterOrder {
typedef GrPlotList::Iter PlotIter;
GrPlot* iterInit(PlotIter* iter, IterOrder order) {
return iter->init(fPlotList, kLRUFirst_IterOrder == order
? GrPlotList::Iter::kTail_IterStart
: GrPlotList::Iter::kHead_IterStart);
void makeMRU(GrPlot* plot);
GrGpu* fGpu;
GrPixelConfig fPixelConfig;
GrSurfaceFlags fFlags;
GrTexture* fTexture;
SkISize fBackingTextureSize;
int fNumPlotsX;
int fNumPlotsY;
bool fBatchUploads;
// allocated array of GrPlots
GrPlot* fPlotArray;
// LRU list of GrPlots (MRU at head - LRU at tail)
GrPlotList fPlotList;