src/gpu/GrBatchAtlas.cpp - skia - Git at Google

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "GrBatchAtlas.h"
 #include "GrBatchTarget.h"
 #include "GrGpu.h"
 #include "GrRectanizer.h"
 #include "GrTracing.h"
 #include "GrVertexBuffer.h"

 static inline void adjust_for_offset(SkIPoint16* loc, const SkIPoint16& offset) {
     loc->fX += offset.fX;
     loc->fY += offset.fY;
 }

 static GrBatchAtlas::AtlasID create_id(uint32_t index, uint64_t generation) {
     SkASSERT(index < (1 << 16));
     SkASSERT(generation < ((uint64_t)1 << 48));
     return generation << 16 | index;
 }

 // The backing GrTexture for a GrBatchAtlas is broken into a spatial grid of GrBatchPlots.
 // The GrBatchPlots keep track of subimage placement via their GrRectanizer. In turn, a GrBatchPlot
 // manages the lifetime of its data using two tokens, a last ref toke and a last upload token.
 // Once a GrBatchPlot is "full" (i.e. there is no room for the new subimage according to the
 // GrRectanizer), it can no longer be used unless the last ref on the GrPlot has already been
 // flushed through to the gpu.

 class BatchPlot : public SkRefCnt {
 public:
     typedef GrBatchAtlas::BatchToken BatchToken;
     SK_DECLARE_INST_COUNT(BatchPlot);
     SK_DECLARE_INTERNAL_LLIST_INTERFACE(BatchPlot);

     // index() refers to the index of the plot in the owning GrAtlas's plot array.  genID() is a
     // monotonically incrementing number which is bumped every time the cpu backing store is
     // wiped, or when the plot itself is evicted from the atlas(ie, there is continuity in genID()
     // across atlas spills)
     uint32_t index() const { return fIndex; }
     uint64_t genID() const { return fGenID; }
     GrBatchAtlas::AtlasID id() { return fID; }

     GrTexture* texture() const { return fTexture; }

     bool addSubImage(int width, int height, const void* image, SkIPoint16* loc, size_t rowBytes)  {
         if (!fRects->addRect(width, height, loc)) {
             return false;
         }

         if (!fData) {
             fData = reinterpret_cast<unsigned char*>(sk_calloc_throw(fBytesPerPixel * fWidth *
                                                                      fHeight));
         }
         const unsigned char* imagePtr = (const unsigned char*)image;
         // point ourselves at the right starting spot
         unsigned char* dataPtr = fData;
         dataPtr += fBytesPerPixel * fWidth * loc->fY;
         dataPtr += fBytesPerPixel * loc->fX;
         // copy into the data buffer
         for (int i = 0; i < height; ++i) {
             memcpy(dataPtr, imagePtr, rowBytes);
             dataPtr += fBytesPerPixel * fWidth;
             imagePtr += rowBytes;
         }

         fDirtyRect.join(loc->fX, loc->fY, loc->fX + width, loc->fY + height);
         adjust_for_offset(loc, fOffset);
         SkDEBUGCODE(fDirty = true;)

         return true;
     }

     // to manage the lifetime of a plot, we use two tokens.  We use last upload token to know when
     // we can 'piggy back' uploads, ie if the last upload hasn't been flushed to gpu, we don't need
     // to issue a new upload even if we update the cpu backing store.  We use lastref to determine
     // when we can evict a plot from the cache, ie if the last ref has already flushed through
     // the gpu then we can reuse the plot
     BatchToken lastUploadToken() const { return fLastUpload; }
     BatchToken lastUseToken() const { return fLastUse; }
     void setLastUploadToken(BatchToken batchToken) {
         SkASSERT(batchToken >= fLastUpload);
         fLastUpload = batchToken;
     }
     void setLastUseToken(BatchToken batchToken) {
         SkASSERT(batchToken >= fLastUse);
         fLastUse = batchToken;
     }

     void uploadToTexture(GrBatchTarget::TextureUploader uploader)  {
         // We should only be issuing uploads if we are in fact dirty
         SkASSERT(fDirty && fData && fTexture);
         TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("skia.gpu"), "GrBatchPlot::uploadToTexture");
         size_t rowBytes = fBytesPerPixel * fRects->width();
         const unsigned char* dataPtr = fData;
         dataPtr += rowBytes * fDirtyRect.fTop;
         dataPtr += fBytesPerPixel * fDirtyRect.fLeft;
         uploader.writeTexturePixels(fTexture,
                                     fOffset.fX + fDirtyRect.fLeft, fOffset.fY + fDirtyRect.fTop,
                                     fDirtyRect.width(), fDirtyRect.height(),
                                     fTexture->config(), dataPtr, rowBytes);
         fDirtyRect.setEmpty();
         SkDEBUGCODE(fDirty = false;)
     }

     void resetRects() {
         SkASSERT(fRects);
         fRects->reset();
         fGenID++;
         fID = create_id(fIndex, fGenID);

         // zero out the plot
         if (fData) {
             sk_bzero(fData, fBytesPerPixel * fWidth * fHeight);
         }

         fDirtyRect.setEmpty();
         SkDEBUGCODE(fDirty = false;)
     }

     uint32_t x() const { return fX; }
     uint32_t y() const { return fY; }

 private:
     BatchPlot()
         : fLastUpload(0)
         , fLastUse(0)
         , fIndex(-1)
         , fGenID(-1)
         , fID(0)
         , fData(NULL)
         , fWidth(0)
         , fHeight(0)
         , fX(0)
         , fY(0)
         , fTexture(NULL)
         , fRects(NULL)
         , fAtlas(NULL)
         , fBytesPerPixel(1)
     #ifdef SK_DEBUG
         , fDirty(false)
     #endif
     {
         fOffset.set(0, 0);
     }

     ~BatchPlot() {
         sk_free(fData);
         fData = NULL;
         delete fRects;
     }

     void init(GrBatchAtlas* atlas, GrTexture* texture, int index, uint64_t generation,
               int offX, int offY, int width, int height, size_t bpp) {
         fIndex = index;
         fGenID = generation;
         fID = create_id(index, generation);
         fWidth = width;
         fHeight = height;
         fX = offX;
         fY = offY;
         fRects = GrRectanizer::Factory(width, height);
         fAtlas = atlas;
         fOffset.set(offX * width, offY * height);
         fBytesPerPixel = bpp;
         fData = NULL;
         fDirtyRect.setEmpty();
         SkDEBUGCODE(fDirty = false;)
         fTexture = texture;
     }

     BatchToken fLastUpload;
     BatchToken fLastUse;

     uint32_t fIndex;
     uint64_t fGenID;
     GrBatchAtlas::AtlasID fID;
     unsigned char* fData;
     uint32_t fWidth;
     uint32_t fHeight;
     uint32_t fX;
     uint32_t fY;
     GrTexture* fTexture;
     GrRectanizer* fRects;
     GrBatchAtlas* fAtlas;
     SkIPoint16 fOffset;        // the offset of the plot in the backing texture
     size_t fBytesPerPixel;
     SkIRect fDirtyRect;
     SkDEBUGCODE(bool fDirty;)

     friend class GrBatchAtlas;

     typedef SkRefCnt INHERITED;
 };

 ////////////////////////////////////////////////////////////////////////////////

 class GrPlotUploader : public GrBatchTarget::Uploader {
 public:
     GrPlotUploader(BatchPlot* plot)
         : INHERITED(plot->lastUploadToken())
         , fPlot(SkRef(plot)) {
         SkASSERT(plot);
     }

     void upload(GrBatchTarget::TextureUploader uploader) override {
         fPlot->uploadToTexture(uploader);
     }

 private:
     SkAutoTUnref<BatchPlot> fPlot;

     typedef GrBatchTarget::Uploader INHERITED;
 };

 ///////////////////////////////////////////////////////////////////////////////

 GrBatchAtlas::GrBatchAtlas(GrTexture* texture, int numPlotsX, int numPlotsY)
     : fTexture(texture)
     , fNumPlotsX(numPlotsX)
     , fNumPlotsY(numPlotsY)
     , fPlotWidth(texture->width() / numPlotsX)
     , fPlotHeight(texture->height() / numPlotsY)
     , fAtlasGeneration(kInvalidAtlasGeneration + 1) {
     SkASSERT(fNumPlotsX * fNumPlotsY <= BulkUseTokenUpdater::kMaxPlots);
     SkASSERT(fPlotWidth * fNumPlotsX == static_cast<uint32_t>(texture->width()));
     SkASSERT(fPlotHeight * fNumPlotsY == static_cast<uint32_t>(texture->height()));

     // We currently do not support compressed atlases...
     SkASSERT(!GrPixelConfigIsCompressed(texture->desc().fConfig));

     // set up allocated plots
     fBPP = GrBytesPerPixel(texture->desc().fConfig);
     fPlotArray = SkNEW_ARRAY(SkAutoTUnref<BatchPlot>, (fNumPlotsX * fNumPlotsY));

     SkAutoTUnref<BatchPlot>* currPlot = fPlotArray;
     for (int y = fNumPlotsY - 1, r = 0; y >= 0; --y, ++r) {
         for (int x = fNumPlotsX - 1, c = 0; x >= 0; --x, ++c) {
             uint32_t id = r * fNumPlotsX + c;
             currPlot->reset(SkNEW(BatchPlot));
             (*currPlot)->init(this, texture, id, 1, x, y, fPlotWidth, fPlotHeight, fBPP);

             // build LRU list
             fPlotList.addToHead(currPlot->get());
             ++currPlot;
         }
     }
 }

 GrBatchAtlas::~GrBatchAtlas() {
     SkSafeUnref(fTexture);
     SkDELETE_ARRAY(fPlotArray);
 }

 void GrBatchAtlas::processEviction(AtlasID id) {
     for (int i = 0; i < fEvictionCallbacks.count(); i++) {
         (*fEvictionCallbacks[i].fFunc)(id, fEvictionCallbacks[i].fData);
     }
 }

 void GrBatchAtlas::makeMRU(BatchPlot* plot) {
     if (fPlotList.head() == plot) {
         return;
     }

     fPlotList.remove(plot);
     fPlotList.addToHead(plot);
 }

 inline void GrBatchAtlas::updatePlot(GrBatchTarget* batchTarget, AtlasID* id, BatchPlot* plot) {
     this->makeMRU(plot);

     // If our most recent upload has already occurred then we have to insert a new
     // upload. Otherwise, we already have a scheduled upload that hasn't yet ocurred.
     // This new update will piggy back on that previously scheduled update.
     if (batchTarget->isIssued(plot->lastUploadToken())) {
         plot->setLastUploadToken(batchTarget->asapToken());
         SkAutoTUnref<GrPlotUploader> uploader(SkNEW_ARGS(GrPlotUploader, (plot)));
         batchTarget->upload(uploader);
     }
     *id = plot->id();
 }

 bool GrBatchAtlas::addToAtlas(AtlasID* id, GrBatchTarget* batchTarget,
                               int width, int height, const void* image, SkIPoint16* loc) {
     // We should already have a texture, TODO clean this up
     SkASSERT(fTexture &&
              static_cast<uint32_t>(width) <= fPlotWidth &&
              static_cast<uint32_t>(height) <= fPlotHeight);

     // now look through all allocated plots for one we can share, in Most Recently Refed order
     GrBatchPlotList::Iter plotIter;
     plotIter.init(fPlotList, GrBatchPlotList::Iter::kHead_IterStart);
     BatchPlot* plot;
     while ((plot = plotIter.get())) {
         if (plot->addSubImage(width, height, image, loc, fBPP * width)) {
             this->updatePlot(batchTarget, id, plot);
             return true;
         }
         plotIter.next();
     }

     // If the above fails, then see if the least recently refed plot has already been flushed to the
     // gpu
     plotIter.init(fPlotList, GrBatchPlotList::Iter::kTail_IterStart);
     plot = plotIter.get();
     SkASSERT(plot);
     if (batchTarget->isIssued(plot->lastUseToken())) {
         this->processEviction(plot->id());
         plot->resetRects();
         SkDEBUGCODE(bool verify = )plot->addSubImage(width, height, image, loc, fBPP * width);
         SkASSERT(verify);
         this->updatePlot(batchTarget, id, plot);
         fAtlasGeneration++;
         return true;
     }

     // The least recently refed plot hasn't been flushed to the gpu yet, however, if we have flushed
     // it to the batch target than we can reuse it.  Our last ref token is guaranteed to be less
     // than or equal to the current token.  If its 'less than' the current token, than we can spin
     // off the plot(ie let the batch target manage it) and create a new plot in its place in our
     // array.  If it is equal to the currentToken, then the caller has to flush draws to the batch
     // target so we can spin off the plot
     if (plot->lastUseToken() == batchTarget->currentToken()) {
         return false;
     }

     // We take an extra ref here so our plot isn't deleted when we reset its index in the array.
     plot->ref();
     int index = plot->index();
     int x = plot->x();
     int y = plot->y();
     uint64_t generation = plot->genID();

     this->processEviction(plot->id());
     fPlotList.remove(plot);
     SkAutoTUnref<BatchPlot>& newPlot = fPlotArray[plot->index()];
     newPlot.reset(SkNEW(BatchPlot));
     newPlot->init(this, fTexture, index, ++generation, x, y, fPlotWidth, fPlotHeight, fBPP);

     fPlotList.addToHead(newPlot.get());
     SkDEBUGCODE(bool verify = )newPlot->addSubImage(width, height, image, loc, fBPP * width);
     SkASSERT(verify);
     newPlot->setLastUploadToken(batchTarget->currentToken());
     SkAutoTUnref<GrPlotUploader> uploader(SkNEW_ARGS(GrPlotUploader, (newPlot)));
     batchTarget->upload(uploader);
     *id = newPlot->id();
     plot->unref();
     fAtlasGeneration++;
     return true;
 }

 bool GrBatchAtlas::hasID(AtlasID id) {
     uint32_t index = GetIndexFromID(id);
     SkASSERT(index < fNumPlotsX * fNumPlotsY);
     return fPlotArray[index]->genID() == GetGenerationFromID(id);
 }

 void GrBatchAtlas::setLastUseToken(AtlasID id, BatchToken batchToken) {
     SkASSERT(this->hasID(id));
     uint32_t index = GetIndexFromID(id);
     SkASSERT(index < fNumPlotsX * fNumPlotsY);
     this->makeMRU(fPlotArray[index]);
     fPlotArray[index]->setLastUseToken(batchToken);
 }

 void GrBatchAtlas::setLastUseTokenBulk(const BulkUseTokenUpdater& updater, BatchToken batchToken) {
     int count = updater.fPlotsToUpdate.count();
     for (int i = 0; i < count; i++) {
         BatchPlot* plot = fPlotArray[updater.fPlotsToUpdate[i]];
         this->makeMRU(plot);
         plot->setLastUseToken(batchToken);
     }
 }
	/*
	* Copyright 2015 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "GrBatchAtlas.h"
	#include "GrBatchTarget.h"
	#include "GrGpu.h"
	#include "GrRectanizer.h"
	#include "GrTracing.h"
	#include "GrVertexBuffer.h"

	static inline void adjust_for_offset(SkIPoint16* loc, const SkIPoint16& offset) {
	loc->fX += offset.fX;
	loc->fY += offset.fY;
	}

	static GrBatchAtlas::AtlasID create_id(uint32_t index, uint64_t generation) {
	SkASSERT(index < (1 << 16));
	SkASSERT(generation < ((uint64_t)1 << 48));
	return generation << 16 \| index;
	}

	// The backing GrTexture for a GrBatchAtlas is broken into a spatial grid of GrBatchPlots.
	// The GrBatchPlots keep track of subimage placement via their GrRectanizer. In turn, a GrBatchPlot
	// manages the lifetime of its data using two tokens, a last ref toke and a last upload token.
	// Once a GrBatchPlot is "full" (i.e. there is no room for the new subimage according to the
	// GrRectanizer), it can no longer be used unless the last ref on the GrPlot has already been
	// flushed through to the gpu.

	class BatchPlot : public SkRefCnt {
	public:
	typedef GrBatchAtlas::BatchToken BatchToken;
	SK_DECLARE_INST_COUNT(BatchPlot);
	SK_DECLARE_INTERNAL_LLIST_INTERFACE(BatchPlot);

	// index() refers to the index of the plot in the owning GrAtlas's plot array. genID() is a
	// monotonically incrementing number which is bumped every time the cpu backing store is
	// wiped, or when the plot itself is evicted from the atlas(ie, there is continuity in genID()
	// across atlas spills)
	uint32_t index() const { return fIndex; }
	uint64_t genID() const { return fGenID; }
	GrBatchAtlas::AtlasID id() { return fID; }

	GrTexture* texture() const { return fTexture; }

	bool addSubImage(int width, int height, const void* image, SkIPoint16* loc, size_t rowBytes) {
	if (!fRects->addRect(width, height, loc)) {
	return false;
	}

	if (!fData) {
	fData = reinterpret_cast<unsigned char>(sk_calloc_throw(fBytesPerPixel fWidth *
	fHeight));
	}
	const unsigned char* imagePtr = (const unsigned char*)image;
	// point ourselves at the right starting spot
	unsigned char* dataPtr = fData;
	dataPtr += fBytesPerPixel * fWidth * loc->fY;
	dataPtr += fBytesPerPixel * loc->fX;
	// copy into the data buffer
	for (int i = 0; i < height; ++i) {
	memcpy(dataPtr, imagePtr, rowBytes);
	dataPtr += fBytesPerPixel * fWidth;
	imagePtr += rowBytes;
	}

	fDirtyRect.join(loc->fX, loc->fY, loc->fX + width, loc->fY + height);
	adjust_for_offset(loc, fOffset);
	SkDEBUGCODE(fDirty = true;)

	return true;
	}

	// to manage the lifetime of a plot, we use two tokens. We use last upload token to know when
	// we can 'piggy back' uploads, ie if the last upload hasn't been flushed to gpu, we don't need
	// to issue a new upload even if we update the cpu backing store. We use lastref to determine
	// when we can evict a plot from the cache, ie if the last ref has already flushed through
	// the gpu then we can reuse the plot
	BatchToken lastUploadToken() const { return fLastUpload; }
	BatchToken lastUseToken() const { return fLastUse; }
	void setLastUploadToken(BatchToken batchToken) {
	SkASSERT(batchToken >= fLastUpload);
	fLastUpload = batchToken;
	}
	void setLastUseToken(BatchToken batchToken) {
	SkASSERT(batchToken >= fLastUse);
	fLastUse = batchToken;
	}

	void uploadToTexture(GrBatchTarget::TextureUploader uploader) {
	// We should only be issuing uploads if we are in fact dirty
	SkASSERT(fDirty && fData && fTexture);
	TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("skia.gpu"), "GrBatchPlot::uploadToTexture");
	size_t rowBytes = fBytesPerPixel * fRects->width();
	const unsigned char* dataPtr = fData;
	dataPtr += rowBytes * fDirtyRect.fTop;
	dataPtr += fBytesPerPixel * fDirtyRect.fLeft;
	uploader.writeTexturePixels(fTexture,
	fOffset.fX + fDirtyRect.fLeft, fOffset.fY + fDirtyRect.fTop,
	fDirtyRect.width(), fDirtyRect.height(),
	fTexture->config(), dataPtr, rowBytes);
	fDirtyRect.setEmpty();
	SkDEBUGCODE(fDirty = false;)
	}

	void resetRects() {
	SkASSERT(fRects);
	fRects->reset();
	fGenID++;
	fID = create_id(fIndex, fGenID);

	// zero out the plot
	if (fData) {
	sk_bzero(fData, fBytesPerPixel * fWidth * fHeight);
	}

	fDirtyRect.setEmpty();
	SkDEBUGCODE(fDirty = false;)
	}

	uint32_t x() const { return fX; }
	uint32_t y() const { return fY; }

	private:
	BatchPlot()
	: fLastUpload(0)
	, fLastUse(0)
	, fIndex(-1)
	, fGenID(-1)
	, fID(0)
	, fData(NULL)
	, fWidth(0)
	, fHeight(0)
	, fX(0)
	, fY(0)
	, fTexture(NULL)
	, fRects(NULL)
	, fAtlas(NULL)
	, fBytesPerPixel(1)
	#ifdef SK_DEBUG
	, fDirty(false)
	#endif
	{
	fOffset.set(0, 0);
	}

	~BatchPlot() {
	sk_free(fData);
	fData = NULL;
	delete fRects;
	}

	void init(GrBatchAtlas* atlas, GrTexture* texture, int index, uint64_t generation,
	int offX, int offY, int width, int height, size_t bpp) {
	fIndex = index;
	fGenID = generation;
	fID = create_id(index, generation);
	fWidth = width;
	fHeight = height;
	fX = offX;
	fY = offY;
	fRects = GrRectanizer::Factory(width, height);
	fAtlas = atlas;
	fOffset.set(offX * width, offY * height);
	fBytesPerPixel = bpp;
	fData = NULL;
	fDirtyRect.setEmpty();
	SkDEBUGCODE(fDirty = false;)
	fTexture = texture;
	}

	BatchToken fLastUpload;
	BatchToken fLastUse;

	uint32_t fIndex;
	uint64_t fGenID;
	GrBatchAtlas::AtlasID fID;
	unsigned char* fData;
	uint32_t fWidth;
	uint32_t fHeight;
	uint32_t fX;
	uint32_t fY;
	GrTexture* fTexture;
	GrRectanizer* fRects;
	GrBatchAtlas* fAtlas;
	SkIPoint16 fOffset; // the offset of the plot in the backing texture
	size_t fBytesPerPixel;
	SkIRect fDirtyRect;
	SkDEBUGCODE(bool fDirty;)

	friend class GrBatchAtlas;

	typedef SkRefCnt INHERITED;
	};

	////////////////////////////////////////////////////////////////////////////////

	class GrPlotUploader : public GrBatchTarget::Uploader {
	public:
	GrPlotUploader(BatchPlot* plot)
	: INHERITED(plot->lastUploadToken())
	, fPlot(SkRef(plot)) {
	SkASSERT(plot);
	}

	void upload(GrBatchTarget::TextureUploader uploader) override {
	fPlot->uploadToTexture(uploader);
	}

	private:
	SkAutoTUnref<BatchPlot> fPlot;

	typedef GrBatchTarget::Uploader INHERITED;
	};

	///////////////////////////////////////////////////////////////////////////////

	GrBatchAtlas::GrBatchAtlas(GrTexture* texture, int numPlotsX, int numPlotsY)
	: fTexture(texture)
	, fNumPlotsX(numPlotsX)
	, fNumPlotsY(numPlotsY)
	, fPlotWidth(texture->width() / numPlotsX)
	, fPlotHeight(texture->height() / numPlotsY)
	, fAtlasGeneration(kInvalidAtlasGeneration + 1) {
	SkASSERT(fNumPlotsX * fNumPlotsY <= BulkUseTokenUpdater::kMaxPlots);
	SkASSERT(fPlotWidth * fNumPlotsX == static_cast<uint32_t>(texture->width()));
	SkASSERT(fPlotHeight * fNumPlotsY == static_cast<uint32_t>(texture->height()));

	// We currently do not support compressed atlases...
	SkASSERT(!GrPixelConfigIsCompressed(texture->desc().fConfig));

	// set up allocated plots
	fBPP = GrBytesPerPixel(texture->desc().fConfig);
	fPlotArray = SkNEW_ARRAY(SkAutoTUnref<BatchPlot>, (fNumPlotsX * fNumPlotsY));

	SkAutoTUnref<BatchPlot>* currPlot = fPlotArray;
	for (int y = fNumPlotsY - 1, r = 0; y >= 0; --y, ++r) {
	for (int x = fNumPlotsX - 1, c = 0; x >= 0; --x, ++c) {
	uint32_t id = r * fNumPlotsX + c;
	currPlot->reset(SkNEW(BatchPlot));
	(*currPlot)->init(this, texture, id, 1, x, y, fPlotWidth, fPlotHeight, fBPP);

	// build LRU list
	fPlotList.addToHead(currPlot->get());
	++currPlot;
	}
	}
	}

	GrBatchAtlas::~GrBatchAtlas() {
	SkSafeUnref(fTexture);
	SkDELETE_ARRAY(fPlotArray);
	}

	void GrBatchAtlas::processEviction(AtlasID id) {
	for (int i = 0; i < fEvictionCallbacks.count(); i++) {
	(*fEvictionCallbacks[i].fFunc)(id, fEvictionCallbacks[i].fData);
	}
	}

	void GrBatchAtlas::makeMRU(BatchPlot* plot) {
	if (fPlotList.head() == plot) {
	return;
	}

	fPlotList.remove(plot);
	fPlotList.addToHead(plot);
	}

	inline void GrBatchAtlas::updatePlot(GrBatchTarget* batchTarget, AtlasID* id, BatchPlot* plot) {
	this->makeMRU(plot);

	// If our most recent upload has already occurred then we have to insert a new
	// upload. Otherwise, we already have a scheduled upload that hasn't yet ocurred.
	// This new update will piggy back on that previously scheduled update.
	if (batchTarget->isIssued(plot->lastUploadToken())) {
	plot->setLastUploadToken(batchTarget->asapToken());
	SkAutoTUnref<GrPlotUploader> uploader(SkNEW_ARGS(GrPlotUploader, (plot)));
	batchTarget->upload(uploader);
	}
	*id = plot->id();
	}

	bool GrBatchAtlas::addToAtlas(AtlasID* id, GrBatchTarget* batchTarget,
	int width, int height, const void* image, SkIPoint16* loc) {
	// We should already have a texture, TODO clean this up
	SkASSERT(fTexture &&
	static_cast<uint32_t>(width) <= fPlotWidth &&
	static_cast<uint32_t>(height) <= fPlotHeight);

	// now look through all allocated plots for one we can share, in Most Recently Refed order
	GrBatchPlotList::Iter plotIter;
	plotIter.init(fPlotList, GrBatchPlotList::Iter::kHead_IterStart);
	BatchPlot* plot;
	while ((plot = plotIter.get())) {
	if (plot->addSubImage(width, height, image, loc, fBPP * width)) {
	this->updatePlot(batchTarget, id, plot);
	return true;
	}
	plotIter.next();
	}

	// If the above fails, then see if the least recently refed plot has already been flushed to the
	// gpu
	plotIter.init(fPlotList, GrBatchPlotList::Iter::kTail_IterStart);
	plot = plotIter.get();
	SkASSERT(plot);
	if (batchTarget->isIssued(plot->lastUseToken())) {
	this->processEviction(plot->id());
	plot->resetRects();
	SkDEBUGCODE(bool verify = )plot->addSubImage(width, height, image, loc, fBPP * width);
	SkASSERT(verify);
	this->updatePlot(batchTarget, id, plot);
	fAtlasGeneration++;
	return true;
	}

	// The least recently refed plot hasn't been flushed to the gpu yet, however, if we have flushed
	// it to the batch target than we can reuse it. Our last ref token is guaranteed to be less
	// than or equal to the current token. If its 'less than' the current token, than we can spin
	// off the plot(ie let the batch target manage it) and create a new plot in its place in our
	// array. If it is equal to the currentToken, then the caller has to flush draws to the batch
	// target so we can spin off the plot
	if (plot->lastUseToken() == batchTarget->currentToken()) {
	return false;
	}

	// We take an extra ref here so our plot isn't deleted when we reset its index in the array.
	plot->ref();
	int index = plot->index();
	int x = plot->x();
	int y = plot->y();
	uint64_t generation = plot->genID();

	this->processEviction(plot->id());
	fPlotList.remove(plot);
	SkAutoTUnref<BatchPlot>& newPlot = fPlotArray[plot->index()];
	newPlot.reset(SkNEW(BatchPlot));
	newPlot->init(this, fTexture, index, ++generation, x, y, fPlotWidth, fPlotHeight, fBPP);

	fPlotList.addToHead(newPlot.get());
	SkDEBUGCODE(bool verify = )newPlot->addSubImage(width, height, image, loc, fBPP * width);
	SkASSERT(verify);
	newPlot->setLastUploadToken(batchTarget->currentToken());
	SkAutoTUnref<GrPlotUploader> uploader(SkNEW_ARGS(GrPlotUploader, (newPlot)));
	batchTarget->upload(uploader);
	*id = newPlot->id();
	plot->unref();
	fAtlasGeneration++;
	return true;
	}

	bool GrBatchAtlas::hasID(AtlasID id) {
	uint32_t index = GetIndexFromID(id);
	SkASSERT(index < fNumPlotsX * fNumPlotsY);
	return fPlotArray[index]->genID() == GetGenerationFromID(id);
	}

	void GrBatchAtlas::setLastUseToken(AtlasID id, BatchToken batchToken) {
	SkASSERT(this->hasID(id));
	uint32_t index = GetIndexFromID(id);
	SkASSERT(index < fNumPlotsX * fNumPlotsY);
	this->makeMRU(fPlotArray[index]);
	fPlotArray[index]->setLastUseToken(batchToken);
	}

	void GrBatchAtlas::setLastUseTokenBulk(const BulkUseTokenUpdater& updater, BatchToken batchToken) {
	int count = updater.fPlotsToUpdate.count();
	for (int i = 0; i < count; i++) {
	BatchPlot* plot = fPlotArray[updater.fPlotsToUpdate[i]];
	this->makeMRU(plot);
	plot->setLastUseToken(batchToken);
	}
	}