src/gpu/GrDrawOpAtlas.h - platform/external/skia - Gitiles

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

 #ifndef GrDrawOpAtlas_DEFINED
 #define GrDrawOpAtlas_DEFINED

 #include "SkPoint.h"
 #include "SkTDArray.h"
 #include "SkTInternalLList.h"

 #include "ops/GrDrawOp.h"

 class GrRectanizer;

 struct GrDrawOpAtlasConfig {
     int numPlotsX() const { return fWidth / fPlotWidth; }
     int numPlotsY() const { return fHeight / fPlotWidth; }
     int fWidth;
     int fHeight;
     int fPlotWidth;
     int fPlotHeight;
 };

 /**
  * This class manages one or more atlas textures on behalf of GrDrawOps. The draw ops that use the
  * atlas perform texture uploads when preparing their draws during flush. The class provides
  * facilities for using GrDrawOpUploadToken to detect data hazards. Op's uploads are performed in
  * "asap" mode until it is impossible to add data without overwriting texels read by draws that
  * have not yet executed on the gpu. At that point, the atlas will attempt to allocate a new
  * atlas texture (or "page") of the same size, up to a maximum number of textures, and upload
  * to that texture. If that's not possible, the uploads are performed "inline" between draws. If a
  * single draw would use enough subimage space to overflow the atlas texture then the atlas will
  * fail to add a subimage. This gives the op the chance to end the draw and begin a new one.
  * Additional uploads will then succeed in inline mode.
  *
  * When the atlas has multiple pages, new uploads are prioritized to the lower index pages, i.e.,
  * it will try to upload to page 0 before page 1 or 2. To keep the atlas from continually using
  * excess space, periodic garbage collection is needed to shift data from the higher index pages to
  * the lower ones, and then eventually remove any pages that are no longer in use. "In use" is
  * determined by using the GrDrawUploadToken system: After a flush each subarea of the page
  * is checked to see whether it was used in that flush; if it is not, a counter is incremented.
  * Once that counter reaches a threshold that subarea is considered to be no longer in use.
  *
  * Garbage collection is initiated by the GrDrawOpAtlas's client via the compact() method. One
  * solution is to make the client a subclass of GrOnFlushCallbackObject, register it with the
  * GrContext via addOnFlushCallbackObject(), and the client's postFlush() method calls compact()
  * and passes in the given GrDrawUploadToken.
  */
 class GrDrawOpAtlas {
 public:
     /**
      * An AtlasID is an opaque handle which callers can use to determine if the atlas contains
      * a specific piece of data.
      */
     typedef uint64_t AtlasID;
     static const uint32_t kInvalidAtlasID = 0;
     static const uint64_t kInvalidAtlasGeneration = 0;

     /**
      * A function pointer for use as a callback during eviction. Whenever GrDrawOpAtlas evicts a
      * specific AtlasID, it will call all of the registered listeners so they can process the
      * eviction.
      */
     typedef void (*EvictionFunc)(GrDrawOpAtlas::AtlasID, void*);

     /**
      * Returns a GrDrawOpAtlas. This function can be called anywhere, but the returned atlas
      * should only be used inside of GrMeshDrawOp::onPrepareDraws.
      *  @param GrPixelConfig    The pixel config which this atlas will store
      *  @param width            width in pixels of the atlas
      *  @param height           height in pixels of the atlas
      *  @param numPlotsX        The number of plots the atlas should be broken up into in the X
      *                          direction
      *  @param numPlotsY        The number of plots the atlas should be broken up into in the Y
      *                          direction
      *  @param func             An eviction function which will be called whenever the atlas has to
      *                          evict data
      *  @param data             User supplied data which will be passed into func whenver an
      *                          eviction occurs
      *  @return                 An initialized GrDrawOpAtlas, or nullptr if creation fails
      */
     static std::unique_ptr<GrDrawOpAtlas> Make(GrContext*, GrPixelConfig,
                                                int width, int height,
                                                int numPlotsX, int numPlotsY,
                                                GrDrawOpAtlas::EvictionFunc func, void* data);

     /**
      * Adds a width x height subimage to the atlas. Upon success it returns an ID and the subimage's
      * coordinates in the backing texture. False is returned if the subimage cannot fit in the
      * atlas without overwriting texels that will be read in the current draw. This indicates that
      * the op should end its current draw and begin another before adding more data. Upon success,
      * an upload of the provided image data will have been added to the GrDrawOp::Target, in "asap"
      * mode if possible, otherwise in "inline" mode. Successive uploads in either mode may be
      * consolidated.
      * NOTE: When the GrDrawOp prepares a draw that reads from the atlas, it must immediately call
      * 'setUseToken' with the currentToken from the GrDrawOp::Target, otherwise the next call to
      * addToAtlas might cause the previous data to be overwritten before it has been read.
      */
     bool addToAtlas(AtlasID*, GrDrawOp::Target*, int width, int height, const void* image,
                     SkIPoint16* loc);

     GrContext* context() const { return fContext; }
     const sk_sp<GrTextureProxy>* getProxies() const { return fProxies; }

     uint64_t atlasGeneration() const { return fAtlasGeneration; }

     inline bool hasID(AtlasID id) {
         uint32_t plot = GetPlotIndexFromID(id);
         SkASSERT(plot < fNumPlots);
         uint32_t page = GetPageIndexFromID(id);
         SkASSERT(page < fNumPages);
         return fPages[page].fPlotArray[plot]->genID() == GetGenerationFromID(id);
     }

     /** To ensure the atlas does not evict a given entry, the client must set the last use token. */
     inline void setLastUseToken(AtlasID id, GrDrawOpUploadToken token) {
         SkASSERT(this->hasID(id));
         uint32_t plotIdx = GetPlotIndexFromID(id);
         SkASSERT(plotIdx < fNumPlots);
         uint32_t pageIdx = GetPageIndexFromID(id);
         SkASSERT(pageIdx < fNumPages);
         Plot* plot = fPages[pageIdx].fPlotArray[plotIdx].get();
         this->makeMRU(plot, pageIdx);
         plot->setLastUseToken(token);
     }

     inline void registerEvictionCallback(EvictionFunc func, void* userData) {
         EvictionData* data = fEvictionCallbacks.append();
         data->fFunc = func;
         data->fData = userData;
     }

     static constexpr auto kMaxPages = 4;
     uint32_t pageCount() { return fNumPages; }

     /**
      * A class which can be handed back to GrDrawOpAtlas for updating last use tokens in bulk.  The
      * current max number of plots per page the GrDrawOpAtlas can handle is 32. If in the future
      * this is insufficient then we can move to a 64 bit int.
      */
     class BulkUseTokenUpdater {
     public:
         BulkUseTokenUpdater() {
             memset(fPlotAlreadyUpdated, 0, sizeof(fPlotAlreadyUpdated));
         }
         BulkUseTokenUpdater(const BulkUseTokenUpdater& that)
             : fPlotsToUpdate(that.fPlotsToUpdate) {
             memcpy(fPlotAlreadyUpdated, that.fPlotAlreadyUpdated, sizeof(fPlotAlreadyUpdated));
         }

         void add(AtlasID id) {
             int index = GrDrawOpAtlas::GetPlotIndexFromID(id);
             int pageIdx = GrDrawOpAtlas::GetPageIndexFromID(id);
             if (!this->find(pageIdx, index)) {
                 this->set(pageIdx, index);
             }
         }

         void reset() {
             fPlotsToUpdate.reset();
             memset(fPlotAlreadyUpdated, 0, sizeof(fPlotAlreadyUpdated));
         }

         struct PlotData {
             PlotData(int pageIdx, int plotIdx) : fPageIndex(pageIdx), fPlotIndex(plotIdx) {}
             uint32_t fPageIndex;
             uint32_t fPlotIndex;
         };

     private:
         bool find(int pageIdx, int index) const {
             SkASSERT(index < kMaxPlots);
             return (fPlotAlreadyUpdated[pageIdx] >> index) & 1;
         }

         void set(int pageIdx, int index) {
             SkASSERT(!this->find(pageIdx, index));
             fPlotAlreadyUpdated[pageIdx] |= (1 << index);
             fPlotsToUpdate.push_back(PlotData(pageIdx, index));
         }

         static constexpr int kMinItems = 4;
         static constexpr int kMaxPlots = 32;
         SkSTArray<kMinItems, PlotData, true> fPlotsToUpdate;
         uint32_t fPlotAlreadyUpdated[kMaxPages];

         friend class GrDrawOpAtlas;
     };

     void setLastUseTokenBulk(const BulkUseTokenUpdater& updater, GrDrawOpUploadToken token) {
         int count = updater.fPlotsToUpdate.count();
         for (int i = 0; i < count; i++) {
             const BulkUseTokenUpdater::PlotData& pd = updater.fPlotsToUpdate[i];
             // it's possible we've added a plot to the updater and subsequently the plot's page
             // was deleted -- so we check to prevent a crash
             if (pd.fPageIndex < fNumPages) {
                 Plot* plot = fPages[pd.fPageIndex].fPlotArray[pd.fPlotIndex].get();
                 this->makeMRU(plot, pd.fPageIndex);
                 plot->setLastUseToken(token);
             }
         }
     }

     void compact(GrDrawOpUploadToken startTokenForNextFlush);

     static constexpr auto kGlyphMaxDim = 256;
     static bool GlyphTooLargeForAtlas(int width, int height) {
         return width > kGlyphMaxDim || height > kGlyphMaxDim;
     }

     static uint32_t GetPageIndexFromID(AtlasID id) {
         return id & 0xff;
     }

 private:
     GrDrawOpAtlas(GrContext*, GrPixelConfig config, int width, int height,
                   int numPlotsX, int numPlotsY);

     /**
      * The backing GrTexture for a GrDrawOpAtlas is broken into a spatial grid of Plots. The Plots
      * keep track of subimage placement via their GrRectanizer. A Plot manages the lifetime of its
      * data using two tokens, a last use token and a last upload token. Once a Plot 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 use of the Plot has already been flushed through to the gpu.
      */
     class Plot : public SkRefCnt {
         SK_DECLARE_INTERNAL_LLIST_INTERFACE(Plot);

     public:
         /** index() is a unique id for the plot relative to the owning GrAtlas and page. */
         uint32_t index() const { return fPlotIndex; }
         /**
          * genID() is incremented when the plot is evicted due to a atlas spill. It is used to know
          * if a particular subimage is still present in the atlas.
          */
         uint64_t genID() const { return fGenID; }
         GrDrawOpAtlas::AtlasID id() const {
             SkASSERT(GrDrawOpAtlas::kInvalidAtlasID != fID);
             return fID;
         }
         SkDEBUGCODE(size_t bpp() const { return fBytesPerPixel; })

         bool addSubImage(int width, int height, const void* image, SkIPoint16* loc);

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

         void uploadToTexture(GrDrawOp::WritePixelsFn&, GrTextureProxy*);
         void resetRects();

         int flushesSinceLastUsed() { return fFlushesSinceLastUse; }
         void resetFlushesSinceLastUsed() { fFlushesSinceLastUse = 0; }
         void incFlushesSinceLastUsed() { fFlushesSinceLastUse++; }

     private:
         Plot(int pageIndex, int plotIndex, uint64_t genID, int offX, int offY, int width, int height,
              GrPixelConfig config);

         ~Plot() override;

         /**
          * Create a clone of this plot. The cloned plot will take the place of the current plot in
          * the atlas
          */
         Plot* clone() const {
             return new Plot(fPageIndex, fPlotIndex, fGenID + 1, fX, fY, fWidth, fHeight, fConfig);
         }

         static GrDrawOpAtlas::AtlasID CreateId(uint32_t pageIdx, uint32_t plotIdx,
                                                uint64_t generation) {
             SkASSERT(pageIdx < (1 << 8));
             SkASSERT(pageIdx < kMaxPages);
             SkASSERT(plotIdx < (1 << 8));
             SkASSERT(generation < ((uint64_t)1 << 48));
             return generation << 16 | plotIdx << 8 | pageIdx;
         }

         GrDrawOpUploadToken   fLastUpload;
         GrDrawOpUploadToken   fLastUse;
         // the number of flushes since this plot has been last used
         int                   fFlushesSinceLastUse;

         struct {
             const uint32_t fPageIndex : 16;
             const uint32_t fPlotIndex : 16;
         };
         uint64_t fGenID;
         GrDrawOpAtlas::AtlasID fID;
         unsigned char* fData;
         const int fWidth;
         const int fHeight;
         const int fX;
         const int fY;
         GrRectanizer* fRects;
         const SkIPoint16 fOffset;  // the offset of the plot in the backing texture
         const GrPixelConfig fConfig;
         const size_t fBytesPerPixel;
         SkIRect fDirtyRect;
         SkDEBUGCODE(bool fDirty);

         friend class GrDrawOpAtlas;

         typedef SkRefCnt INHERITED;
     };

     typedef SkTInternalLList<Plot> PlotList;

     static uint32_t GetPlotIndexFromID(AtlasID id) {
         return (id >> 8) & 0xff;
     }

     // top 48 bits are reserved for the generation ID
     static uint64_t GetGenerationFromID(AtlasID id) {
         return (id >> 16) & 0xffffffffffff;
     }

     inline bool updatePlot(GrDrawOp::Target*, AtlasID*, Plot*);

     inline void makeMRU(Plot* plot, int pageIdx) {
         if (fPages[pageIdx].fPlotList.head() == plot) {
             return;
         }

         fPages[pageIdx].fPlotList.remove(plot);
         fPages[pageIdx].fPlotList.addToHead(plot);

         // No MRU update for pages -- since we will always try to add from
         // the front and remove from the back there is no need for MRU.
     }

     bool createNewPage();
     void deleteLastPage();

     void processEviction(AtlasID);
     inline void processEvictionAndResetRects(Plot* plot) {
         this->processEviction(plot->id());
         plot->resetRects();
     }

     GrContext*            fContext;
     GrPixelConfig         fPixelConfig;
     int                   fTextureWidth;
     int                   fTextureHeight;
     int                   fPlotWidth;
     int                   fPlotHeight;
     SkDEBUGCODE(uint32_t  fNumPlots;)

     uint64_t              fAtlasGeneration;
     // nextTokenToFlush() value at the end of the previous flush
     GrDrawOpUploadToken   fPrevFlushToken;

     struct EvictionData {
         EvictionFunc fFunc;
         void* fData;
     };

     SkTDArray<EvictionData> fEvictionCallbacks;

     struct Page {
         // allocated array of Plots
         std::unique_ptr<sk_sp<Plot>[]> fPlotArray;
         // LRU list of Plots (MRU at head - LRU at tail)
         PlotList fPlotList;
     };
     // proxies kept separate to make it easier to pass them up to client
     sk_sp<GrTextureProxy> fProxies[kMaxPages];
     Page fPages[kMaxPages];
     uint32_t fNumPages;
 };

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

	#ifndef GrDrawOpAtlas_DEFINED
	#define GrDrawOpAtlas_DEFINED

	#include "SkPoint.h"
	#include "SkTDArray.h"
	#include "SkTInternalLList.h"

	#include "ops/GrDrawOp.h"

	class GrRectanizer;

	struct GrDrawOpAtlasConfig {
	int numPlotsX() const { return fWidth / fPlotWidth; }
	int numPlotsY() const { return fHeight / fPlotWidth; }
	int fWidth;
	int fHeight;
	int fPlotWidth;
	int fPlotHeight;
	};

	/**
	* This class manages one or more atlas textures on behalf of GrDrawOps. The draw ops that use the
	* atlas perform texture uploads when preparing their draws during flush. The class provides
	* facilities for using GrDrawOpUploadToken to detect data hazards. Op's uploads are performed in
	* "asap" mode until it is impossible to add data without overwriting texels read by draws that
	* have not yet executed on the gpu. At that point, the atlas will attempt to allocate a new
	* atlas texture (or "page") of the same size, up to a maximum number of textures, and upload
	* to that texture. If that's not possible, the uploads are performed "inline" between draws. If a
	* single draw would use enough subimage space to overflow the atlas texture then the atlas will
	* fail to add a subimage. This gives the op the chance to end the draw and begin a new one.
	* Additional uploads will then succeed in inline mode.
	*
	* When the atlas has multiple pages, new uploads are prioritized to the lower index pages, i.e.,
	* it will try to upload to page 0 before page 1 or 2. To keep the atlas from continually using
	* excess space, periodic garbage collection is needed to shift data from the higher index pages to
	* the lower ones, and then eventually remove any pages that are no longer in use. "In use" is
	* determined by using the GrDrawUploadToken system: After a flush each subarea of the page
	* is checked to see whether it was used in that flush; if it is not, a counter is incremented.
	* Once that counter reaches a threshold that subarea is considered to be no longer in use.
	*
	* Garbage collection is initiated by the GrDrawOpAtlas's client via the compact() method. One
	* solution is to make the client a subclass of GrOnFlushCallbackObject, register it with the
	* GrContext via addOnFlushCallbackObject(), and the client's postFlush() method calls compact()
	* and passes in the given GrDrawUploadToken.
	*/
	class GrDrawOpAtlas {
	public:
	/**
	* An AtlasID is an opaque handle which callers can use to determine if the atlas contains
	* a specific piece of data.
	*/
	typedef uint64_t AtlasID;
	static const uint32_t kInvalidAtlasID = 0;
	static const uint64_t kInvalidAtlasGeneration = 0;

	/**
	* A function pointer for use as a callback during eviction. Whenever GrDrawOpAtlas evicts a
	* specific AtlasID, it will call all of the registered listeners so they can process the
	* eviction.
	*/
	typedef void (EvictionFunc)(GrDrawOpAtlas::AtlasID, void);

	/**
	* Returns a GrDrawOpAtlas. This function can be called anywhere, but the returned atlas
	* should only be used inside of GrMeshDrawOp::onPrepareDraws.
	* @param GrPixelConfig The pixel config which this atlas will store
	* @param width width in pixels of the atlas
	* @param height height in pixels of the atlas
	* @param numPlotsX The number of plots the atlas should be broken up into in the X
	* direction
	* @param numPlotsY The number of plots the atlas should be broken up into in the Y
	* direction
	* @param func An eviction function which will be called whenever the atlas has to
	* evict data
	* @param data User supplied data which will be passed into func whenver an
	* eviction occurs
	* @return An initialized GrDrawOpAtlas, or nullptr if creation fails
	*/
	static std::unique_ptr<GrDrawOpAtlas> Make(GrContext*, GrPixelConfig,
	int width, int height,
	int numPlotsX, int numPlotsY,
	GrDrawOpAtlas::EvictionFunc func, void* data);

	/**
	* Adds a width x height subimage to the atlas. Upon success it returns an ID and the subimage's
	* coordinates in the backing texture. False is returned if the subimage cannot fit in the
	* atlas without overwriting texels that will be read in the current draw. This indicates that
	* the op should end its current draw and begin another before adding more data. Upon success,
	* an upload of the provided image data will have been added to the GrDrawOp::Target, in "asap"
	* mode if possible, otherwise in "inline" mode. Successive uploads in either mode may be
	* consolidated.
	* NOTE: When the GrDrawOp prepares a draw that reads from the atlas, it must immediately call
	* 'setUseToken' with the currentToken from the GrDrawOp::Target, otherwise the next call to
	* addToAtlas might cause the previous data to be overwritten before it has been read.
	*/
	bool addToAtlas(AtlasID, GrDrawOp::Target, int width, int height, const void* image,
	SkIPoint16* loc);

	GrContext* context() const { return fContext; }
	const sk_sp<GrTextureProxy>* getProxies() const { return fProxies; }

	uint64_t atlasGeneration() const { return fAtlasGeneration; }

	inline bool hasID(AtlasID id) {
	uint32_t plot = GetPlotIndexFromID(id);
	SkASSERT(plot < fNumPlots);
	uint32_t page = GetPageIndexFromID(id);
	SkASSERT(page < fNumPages);
	return fPages[page].fPlotArray[plot]->genID() == GetGenerationFromID(id);
	}

	/** To ensure the atlas does not evict a given entry, the client must set the last use token. */
	inline void setLastUseToken(AtlasID id, GrDrawOpUploadToken token) {
	SkASSERT(this->hasID(id));
	uint32_t plotIdx = GetPlotIndexFromID(id);
	SkASSERT(plotIdx < fNumPlots);
	uint32_t pageIdx = GetPageIndexFromID(id);
	SkASSERT(pageIdx < fNumPages);
	Plot* plot = fPages[pageIdx].fPlotArray[plotIdx].get();
	this->makeMRU(plot, pageIdx);
	plot->setLastUseToken(token);
	}

	inline void registerEvictionCallback(EvictionFunc func, void* userData) {
	EvictionData* data = fEvictionCallbacks.append();
	data->fFunc = func;
	data->fData = userData;
	}

	static constexpr auto kMaxPages = 4;
	uint32_t pageCount() { return fNumPages; }

	/**
	* A class which can be handed back to GrDrawOpAtlas for updating last use tokens in bulk. The
	* current max number of plots per page the GrDrawOpAtlas can handle is 32. If in the future
	* this is insufficient then we can move to a 64 bit int.
	*/
	class BulkUseTokenUpdater {
	public:
	BulkUseTokenUpdater() {
	memset(fPlotAlreadyUpdated, 0, sizeof(fPlotAlreadyUpdated));
	}
	BulkUseTokenUpdater(const BulkUseTokenUpdater& that)
	: fPlotsToUpdate(that.fPlotsToUpdate) {
	memcpy(fPlotAlreadyUpdated, that.fPlotAlreadyUpdated, sizeof(fPlotAlreadyUpdated));
	}

	void add(AtlasID id) {
	int index = GrDrawOpAtlas::GetPlotIndexFromID(id);
	int pageIdx = GrDrawOpAtlas::GetPageIndexFromID(id);
	if (!this->find(pageIdx, index)) {
	this->set(pageIdx, index);
	}
	}

	void reset() {
	fPlotsToUpdate.reset();
	memset(fPlotAlreadyUpdated, 0, sizeof(fPlotAlreadyUpdated));
	}

	struct PlotData {
	PlotData(int pageIdx, int plotIdx) : fPageIndex(pageIdx), fPlotIndex(plotIdx) {}
	uint32_t fPageIndex;
	uint32_t fPlotIndex;
	};

	private:
	bool find(int pageIdx, int index) const {
	SkASSERT(index < kMaxPlots);
	return (fPlotAlreadyUpdated[pageIdx] >> index) & 1;
	}

	void set(int pageIdx, int index) {
	SkASSERT(!this->find(pageIdx, index));
	fPlotAlreadyUpdated[pageIdx] \|= (1 << index);
	fPlotsToUpdate.push_back(PlotData(pageIdx, index));
	}

	static constexpr int kMinItems = 4;
	static constexpr int kMaxPlots = 32;
	SkSTArray<kMinItems, PlotData, true> fPlotsToUpdate;
	uint32_t fPlotAlreadyUpdated[kMaxPages];

	friend class GrDrawOpAtlas;
	};

	void setLastUseTokenBulk(const BulkUseTokenUpdater& updater, GrDrawOpUploadToken token) {
	int count = updater.fPlotsToUpdate.count();
	for (int i = 0; i < count; i++) {
	const BulkUseTokenUpdater::PlotData& pd = updater.fPlotsToUpdate[i];
	// it's possible we've added a plot to the updater and subsequently the plot's page
	// was deleted -- so we check to prevent a crash
	if (pd.fPageIndex < fNumPages) {
	Plot* plot = fPages[pd.fPageIndex].fPlotArray[pd.fPlotIndex].get();
	this->makeMRU(plot, pd.fPageIndex);
	plot->setLastUseToken(token);
	}
	}
	}

	void compact(GrDrawOpUploadToken startTokenForNextFlush);

	static constexpr auto kGlyphMaxDim = 256;
	static bool GlyphTooLargeForAtlas(int width, int height) {
	return width > kGlyphMaxDim \|\| height > kGlyphMaxDim;
	}

	static uint32_t GetPageIndexFromID(AtlasID id) {
	return id & 0xff;
	}

	private:
	GrDrawOpAtlas(GrContext*, GrPixelConfig config, int width, int height,
	int numPlotsX, int numPlotsY);

	/**
	* The backing GrTexture for a GrDrawOpAtlas is broken into a spatial grid of Plots. The Plots
	* keep track of subimage placement via their GrRectanizer. A Plot manages the lifetime of its
	* data using two tokens, a last use token and a last upload token. Once a Plot 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 use of the Plot has already been flushed through to the gpu.
	*/
	class Plot : public SkRefCnt {
	SK_DECLARE_INTERNAL_LLIST_INTERFACE(Plot);

	public:
	/** index() is a unique id for the plot relative to the owning GrAtlas and page. */
	uint32_t index() const { return fPlotIndex; }
	/**
	* genID() is incremented when the plot is evicted due to a atlas spill. It is used to know
	* if a particular subimage is still present in the atlas.
	*/
	uint64_t genID() const { return fGenID; }
	GrDrawOpAtlas::AtlasID id() const {
	SkASSERT(GrDrawOpAtlas::kInvalidAtlasID != fID);
	return fID;
	}
	SkDEBUGCODE(size_t bpp() const { return fBytesPerPixel; })

	bool addSubImage(int width, int height, const void* image, SkIPoint16* loc);

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

	void uploadToTexture(GrDrawOp::WritePixelsFn&, GrTextureProxy*);
	void resetRects();

	int flushesSinceLastUsed() { return fFlushesSinceLastUse; }
	void resetFlushesSinceLastUsed() { fFlushesSinceLastUse = 0; }
	void incFlushesSinceLastUsed() { fFlushesSinceLastUse++; }

	private:
	Plot(int pageIndex, int plotIndex, uint64_t genID, int offX, int offY, int width, int height,
	GrPixelConfig config);

	~Plot() override;

	/**
	* Create a clone of this plot. The cloned plot will take the place of the current plot in
	* the atlas
	*/
	Plot* clone() const {
	return new Plot(fPageIndex, fPlotIndex, fGenID + 1, fX, fY, fWidth, fHeight, fConfig);
	}

	static GrDrawOpAtlas::AtlasID CreateId(uint32_t pageIdx, uint32_t plotIdx,
	uint64_t generation) {
	SkASSERT(pageIdx < (1 << 8));
	SkASSERT(pageIdx < kMaxPages);
	SkASSERT(plotIdx < (1 << 8));
	SkASSERT(generation < ((uint64_t)1 << 48));
	return generation << 16 \| plotIdx << 8 \| pageIdx;
	}

	GrDrawOpUploadToken fLastUpload;
	GrDrawOpUploadToken fLastUse;
	// the number of flushes since this plot has been last used
	int fFlushesSinceLastUse;

	struct {
	const uint32_t fPageIndex : 16;
	const uint32_t fPlotIndex : 16;
	};
	uint64_t fGenID;
	GrDrawOpAtlas::AtlasID fID;
	unsigned char* fData;
	const int fWidth;
	const int fHeight;
	const int fX;
	const int fY;
	GrRectanizer* fRects;
	const SkIPoint16 fOffset; // the offset of the plot in the backing texture
	const GrPixelConfig fConfig;
	const size_t fBytesPerPixel;
	SkIRect fDirtyRect;
	SkDEBUGCODE(bool fDirty);

	friend class GrDrawOpAtlas;

	typedef SkRefCnt INHERITED;
	};

	typedef SkTInternalLList<Plot> PlotList;

	static uint32_t GetPlotIndexFromID(AtlasID id) {
	return (id >> 8) & 0xff;
	}

	// top 48 bits are reserved for the generation ID
	static uint64_t GetGenerationFromID(AtlasID id) {
	return (id >> 16) & 0xffffffffffff;
	}

	inline bool updatePlot(GrDrawOp::Target, AtlasID, Plot*);

	inline void makeMRU(Plot* plot, int pageIdx) {
	if (fPages[pageIdx].fPlotList.head() == plot) {
	return;
	}

	fPages[pageIdx].fPlotList.remove(plot);
	fPages[pageIdx].fPlotList.addToHead(plot);

	// No MRU update for pages -- since we will always try to add from
	// the front and remove from the back there is no need for MRU.
	}

	bool createNewPage();
	void deleteLastPage();

	void processEviction(AtlasID);
	inline void processEvictionAndResetRects(Plot* plot) {
	this->processEviction(plot->id());
	plot->resetRects();
	}

	GrContext* fContext;
	GrPixelConfig fPixelConfig;
	int fTextureWidth;
	int fTextureHeight;
	int fPlotWidth;
	int fPlotHeight;
	SkDEBUGCODE(uint32_t fNumPlots;)

	uint64_t fAtlasGeneration;
	// nextTokenToFlush() value at the end of the previous flush
	GrDrawOpUploadToken fPrevFlushToken;

	struct EvictionData {
	EvictionFunc fFunc;
	void* fData;
	};

	SkTDArray<EvictionData> fEvictionCallbacks;

	struct Page {
	// allocated array of Plots
	std::unique_ptr<sk_sp<Plot>[]> fPlotArray;
	// LRU list of Plots (MRU at head - LRU at tail)
	PlotList fPlotList;
	};
	// proxies kept separate to make it easier to pass them up to client
	sk_sp<GrTextureProxy> fProxies[kMaxPages];
	Page fPages[kMaxPages];
	uint32_t fNumPages;
	};

	#endif