src/gpu/GrLayerCache.h - skia - Git at Google

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #ifndef GrLayerCache_DEFINED
 #define GrLayerCache_DEFINED

 #include "GrAtlas.h"
 #include "GrPictureUtils.h"
 #include "GrRect.h"
 #include "SkChecksum.h"
 #include "SkTDynamicHash.h"
 #include "SkMessageBus.h"

 class SkPicture;

 // The layer cache listens for these messages to purge picture-related resources.
 struct GrPictureDeletedMessage {
     uint32_t pictureID;
 };

 // GrPictureInfo stores the atlas plots used by a single picture. A single
 // plot may be used to store layers from multiple pictures.
 struct GrPictureInfo {
 public:
     // for SkTDynamicHash - just use the pictureID as the hash key
     static const uint32_t& GetKey(const GrPictureInfo& pictInfo) { return pictInfo.fPictureID; }
     static uint32_t Hash(const uint32_t& key) { return SkChecksum::Mix(key); }

     // GrPictureInfo proper
     GrPictureInfo(uint32_t pictureID) : fPictureID(pictureID) { }

     const uint32_t fPictureID;

     GrAtlas::ClientPlotUsage  fPlotUsage;
 };

 // GrCachedLayer encapsulates the caching information for a single saveLayer.
 //
 // Atlased layers get a ref to the backing GrTexture while non-atlased layers
 // get a ref to the GrTexture in which they reside. In both cases 'fRect'
 // contains the layer's extent in its texture.
 // Atlased layers also get a pointer to the plot in which they reside.
 // For non-atlased layers, the lock field just corresponds to locking in
 // the resource cache. For atlased layers, it implements an additional level
 // of locking to allow atlased layers to be reused multiple times.
 struct GrCachedLayer {
 public:
     // For SkTDynamicHash
     struct Key {
         Key(uint32_t pictureID, int start, int stop, const SkMatrix& ctm)
         : fPictureID(pictureID)
         , fStart(start)
         , fStop(stop)
         , fCTM(ctm) {
             fCTM.getType(); // force initialization of type so hashes match

             // Key needs to be tightly packed.
             GR_STATIC_ASSERT(sizeof(Key) == sizeof(uint32_t) + 2 * sizeof(int) +
                                             9 * sizeof(SkScalar) + sizeof(uint32_t));
         }

         bool operator==(const Key& other) const {
             return fPictureID == other.fPictureID &&
                    fStart == other.fStart &&
                    fStop == other.fStop &&
                    fCTM.cheapEqualTo(other.fCTM);
         }

         uint32_t pictureID() const { return fPictureID; }
         int start() const { return fStart; }
         int stop() const { return fStop; }
         const SkMatrix& ctm() const { return fCTM; }

     private:
         // ID of the picture of which this layer is a part
         const uint32_t fPictureID;
         // The range of commands in the picture this layer represents
         const int      fStart;
         const int      fStop;
         // The CTM applied to this layer in the picture
         SkMatrix       fCTM;
     };

     static const Key& GetKey(const GrCachedLayer& layer) { return layer.fKey; }
     static uint32_t Hash(const Key& key) {
         return SkChecksum::Murmur3(reinterpret_cast<const uint32_t*>(&key), sizeof(Key));
     }

     // GrCachedLayer proper
     GrCachedLayer(uint32_t pictureID, int start, int stop, const SkMatrix& ctm)
         : fKey(pictureID, start, stop, ctm)
         , fTexture(NULL)
         , fRect(GrIRect16::MakeEmpty())
         , fPlot(NULL)
         , fLocked(false) {
         SkASSERT(SK_InvalidGenID != pictureID && start >= 0 && stop >= 0);
     }

     ~GrCachedLayer() {
         SkSafeUnref(fTexture);
     }

     uint32_t pictureID() const { return fKey.pictureID(); }
     int start() const { return fKey.start(); }
     int stop() const { return fKey.stop(); }
     const SkMatrix& ctm() const { return fKey.ctm(); }

     void setTexture(GrTexture* texture, const GrIRect16& rect) {
         SkRefCnt_SafeAssign(fTexture, texture);
         fRect = rect;
     }
     GrTexture* texture() { return fTexture; }
     const GrIRect16& rect() const { return fRect; }

     void setPlot(GrPlot* plot) {
         SkASSERT(NULL == fPlot);
         fPlot = plot;
     }
     GrPlot* plot() { return fPlot; }

     bool isAtlased() const { return NULL != fPlot; }

     void setLocked(bool locked) { fLocked = locked; }
     bool locked() const { return fLocked; }

     SkDEBUGCODE(const GrPlot* plot() const { return fPlot; })
     SkDEBUGCODE(void validate(const GrTexture* backingTexture) const;)

 private:
     const Key       fKey;

     // fTexture is a ref on the atlasing texture for atlased layers and a
     // ref on a GrTexture for non-atlased textures.
     GrTexture*      fTexture;

     // For both atlased and non-atlased layers 'fRect' contains the  bound of
     // the layer in whichever texture it resides. It is empty when 'fTexture'
     // is NULL.
     GrIRect16       fRect;

     // For atlased layers, fPlot stores the atlas plot in which the layer rests.
     // It is always NULL for non-atlased layers.
     GrPlot*         fPlot;

     // For non-atlased layers 'fLocked' should always match "NULL != fTexture".
     // (i.e., if there is a texture it is locked).
     // For atlased layers, 'fLocked' is true if the layer is in a plot and
     // actively required for rendering. If the layer is in a plot but not
     // actively required for rendering, then 'fLocked' is false. If the
     // layer isn't in a plot then is can never be locked.
     bool            fLocked;
 };

 // The GrLayerCache caches pre-computed saveLayers for later rendering.
 // Non-atlased layers are stored in their own GrTexture while the atlased
 // layers share a single GrTexture.
 // Unlike the GrFontCache, the GrTexture atlas only has one GrAtlas (for 8888)
 // and one GrPlot (for the entire atlas). As such, the GrLayerCache
 // roughly combines the functionality of the GrFontCache and GrTextStrike
 // classes.
 class GrLayerCache {
 public:
     GrLayerCache(GrContext*);
     ~GrLayerCache();

     // As a cache, the GrLayerCache can be ordered to free up all its cached
     // elements by the GrContext
     void freeAll();

     GrCachedLayer* findLayer(const SkPicture* picture, int start, int stop, const SkMatrix& ctm);
     GrCachedLayer* findLayerOrCreate(const SkPicture* picture,
                                      int start, int stop,
                                      const SkMatrix& ctm);

     // Inform the cache that layer's cached image is now required. Return true
     // if it was found in the ResourceCache and doesn't need to be regenerated.
     // If false is returned the caller should (re)render the layer into the
     // newly acquired texture.
     bool lock(GrCachedLayer* layer, const GrTextureDesc& desc);

     // Inform the cache that layer's cached image is not currently required
     void unlock(GrCachedLayer* layer);

     // Setup to be notified when 'picture' is deleted
     void trackPicture(const SkPicture* picture);

     // Cleanup after any SkPicture deletions
     void processDeletedPictures();

     SkDEBUGCODE(void validate() const;)

 private:
     static const int kAtlasTextureWidth = 1024;
     static const int kAtlasTextureHeight = 1024;

     static const int kNumPlotsX = 2;
     static const int kNumPlotsY = 2;

     static const int kPlotWidth = kAtlasTextureWidth / kNumPlotsX;
     static const int kPlotHeight = kAtlasTextureHeight / kNumPlotsY;

     GrContext*                fContext;  // pointer back to owning context
     SkAutoTDelete<GrAtlas>    fAtlas;    // TODO: could lazily allocate

     // We cache this information here (rather then, say, on the owning picture)
     // because we want to be able to clean it up as needed (e.g., if a picture
     // is leaked and never cleans itself up we still want to be able to
     // remove the GrPictureInfo once its layers are purged from all the atlas
     // plots).
     SkTDynamicHash<GrPictureInfo, uint32_t> fPictureHash;

     SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key> fLayerHash;

     SkMessageBus<GrPictureDeletedMessage>::Inbox fPictDeletionInbox;

     SkAutoTUnref<SkPicture::DeletionListener> fDeletionListener;

     // This implements a plot-centric locking mechanism (since the atlas
     // backing texture is always locked). Each layer that is locked (i.e.,
     // needed for the current rendering) in a plot increments the plot lock
     // count for that plot. Similarly, once a rendering is complete all the
     // layers used in it decrement the lock count for the used plots.
     // Plots with a 0 lock count are open for recycling/purging.
     int fPlotLocks[kNumPlotsX * kNumPlotsY];

     void initAtlas();
     GrCachedLayer* createLayer(const SkPicture* picture, int start, int stop, const SkMatrix& ctm);

     // Remove all the layers (and unlock any resources) associated with 'pictureID'
     void purge(uint32_t pictureID);

     static bool PlausiblyAtlasable(int width, int height) {
         return width <= kPlotWidth && height <= kPlotHeight;
     }

     // Try to find a purgeable plot and clear it out. Return true if a plot
     // was purged; false otherwise.
     bool purgePlot();

     // for testing
     friend class TestingAccess;
     int numLayers() const { return fLayerHash.count(); }
 };

 #endif
	/*
	* Copyright 2014 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#ifndef GrLayerCache_DEFINED
	#define GrLayerCache_DEFINED

	#include "GrAtlas.h"
	#include "GrPictureUtils.h"
	#include "GrRect.h"
	#include "SkChecksum.h"
	#include "SkTDynamicHash.h"
	#include "SkMessageBus.h"

	class SkPicture;

	// The layer cache listens for these messages to purge picture-related resources.
	struct GrPictureDeletedMessage {
	uint32_t pictureID;
	};

	// GrPictureInfo stores the atlas plots used by a single picture. A single
	// plot may be used to store layers from multiple pictures.
	struct GrPictureInfo {
	public:
	// for SkTDynamicHash - just use the pictureID as the hash key
	static const uint32_t& GetKey(const GrPictureInfo& pictInfo) { return pictInfo.fPictureID; }
	static uint32_t Hash(const uint32_t& key) { return SkChecksum::Mix(key); }

	// GrPictureInfo proper
	GrPictureInfo(uint32_t pictureID) : fPictureID(pictureID) { }

	const uint32_t fPictureID;

	GrAtlas::ClientPlotUsage fPlotUsage;
	};

	// GrCachedLayer encapsulates the caching information for a single saveLayer.
	//
	// Atlased layers get a ref to the backing GrTexture while non-atlased layers
	// get a ref to the GrTexture in which they reside. In both cases 'fRect'
	// contains the layer's extent in its texture.
	// Atlased layers also get a pointer to the plot in which they reside.
	// For non-atlased layers, the lock field just corresponds to locking in
	// the resource cache. For atlased layers, it implements an additional level
	// of locking to allow atlased layers to be reused multiple times.
	struct GrCachedLayer {
	public:
	// For SkTDynamicHash
	struct Key {
	Key(uint32_t pictureID, int start, int stop, const SkMatrix& ctm)
	: fPictureID(pictureID)
	, fStart(start)
	, fStop(stop)
	, fCTM(ctm) {
	fCTM.getType(); // force initialization of type so hashes match

	// Key needs to be tightly packed.
	GR_STATIC_ASSERT(sizeof(Key) == sizeof(uint32_t) + 2 * sizeof(int) +
	9 * sizeof(SkScalar) + sizeof(uint32_t));
	}

	bool operator==(const Key& other) const {
	return fPictureID == other.fPictureID &&
	fStart == other.fStart &&
	fStop == other.fStop &&
	fCTM.cheapEqualTo(other.fCTM);
	}

	uint32_t pictureID() const { return fPictureID; }
	int start() const { return fStart; }
	int stop() const { return fStop; }
	const SkMatrix& ctm() const { return fCTM; }

	private:
	// ID of the picture of which this layer is a part
	const uint32_t fPictureID;
	// The range of commands in the picture this layer represents
	const int fStart;
	const int fStop;
	// The CTM applied to this layer in the picture
	SkMatrix fCTM;
	};

	static const Key& GetKey(const GrCachedLayer& layer) { return layer.fKey; }
	static uint32_t Hash(const Key& key) {
	return SkChecksum::Murmur3(reinterpret_cast<const uint32_t*>(&key), sizeof(Key));
	}

	// GrCachedLayer proper
	GrCachedLayer(uint32_t pictureID, int start, int stop, const SkMatrix& ctm)
	: fKey(pictureID, start, stop, ctm)
	, fTexture(NULL)
	, fRect(GrIRect16::MakeEmpty())
	, fPlot(NULL)
	, fLocked(false) {
	SkASSERT(SK_InvalidGenID != pictureID && start >= 0 && stop >= 0);
	}

	~GrCachedLayer() {
	SkSafeUnref(fTexture);
	}

	uint32_t pictureID() const { return fKey.pictureID(); }
	int start() const { return fKey.start(); }
	int stop() const { return fKey.stop(); }
	const SkMatrix& ctm() const { return fKey.ctm(); }

	void setTexture(GrTexture* texture, const GrIRect16& rect) {
	SkRefCnt_SafeAssign(fTexture, texture);
	fRect = rect;
	}
	GrTexture* texture() { return fTexture; }
	const GrIRect16& rect() const { return fRect; }

	void setPlot(GrPlot* plot) {
	SkASSERT(NULL == fPlot);
	fPlot = plot;
	}
	GrPlot* plot() { return fPlot; }

	bool isAtlased() const { return NULL != fPlot; }

	void setLocked(bool locked) { fLocked = locked; }
	bool locked() const { return fLocked; }

	SkDEBUGCODE(const GrPlot* plot() const { return fPlot; })
	SkDEBUGCODE(void validate(const GrTexture* backingTexture) const;)

	private:
	const Key fKey;

	// fTexture is a ref on the atlasing texture for atlased layers and a
	// ref on a GrTexture for non-atlased textures.
	GrTexture* fTexture;

	// For both atlased and non-atlased layers 'fRect' contains the bound of
	// the layer in whichever texture it resides. It is empty when 'fTexture'
	// is NULL.
	GrIRect16 fRect;

	// For atlased layers, fPlot stores the atlas plot in which the layer rests.
	// It is always NULL for non-atlased layers.
	GrPlot* fPlot;

	// For non-atlased layers 'fLocked' should always match "NULL != fTexture".
	// (i.e., if there is a texture it is locked).
	// For atlased layers, 'fLocked' is true if the layer is in a plot and
	// actively required for rendering. If the layer is in a plot but not
	// actively required for rendering, then 'fLocked' is false. If the
	// layer isn't in a plot then is can never be locked.
	bool fLocked;
	};

	// The GrLayerCache caches pre-computed saveLayers for later rendering.
	// Non-atlased layers are stored in their own GrTexture while the atlased
	// layers share a single GrTexture.
	// Unlike the GrFontCache, the GrTexture atlas only has one GrAtlas (for 8888)
	// and one GrPlot (for the entire atlas). As such, the GrLayerCache
	// roughly combines the functionality of the GrFontCache and GrTextStrike
	// classes.
	class GrLayerCache {
	public:
	GrLayerCache(GrContext*);
	~GrLayerCache();

	// As a cache, the GrLayerCache can be ordered to free up all its cached
	// elements by the GrContext
	void freeAll();

	GrCachedLayer* findLayer(const SkPicture* picture, int start, int stop, const SkMatrix& ctm);
	GrCachedLayer* findLayerOrCreate(const SkPicture* picture,
	int start, int stop,
	const SkMatrix& ctm);

	// Inform the cache that layer's cached image is now required. Return true
	// if it was found in the ResourceCache and doesn't need to be regenerated.
	// If false is returned the caller should (re)render the layer into the
	// newly acquired texture.
	bool lock(GrCachedLayer* layer, const GrTextureDesc& desc);

	// Inform the cache that layer's cached image is not currently required
	void unlock(GrCachedLayer* layer);

	// Setup to be notified when 'picture' is deleted
	void trackPicture(const SkPicture* picture);

	// Cleanup after any SkPicture deletions
	void processDeletedPictures();

	SkDEBUGCODE(void validate() const;)

	private:
	static const int kAtlasTextureWidth = 1024;
	static const int kAtlasTextureHeight = 1024;

	static const int kNumPlotsX = 2;
	static const int kNumPlotsY = 2;

	static const int kPlotWidth = kAtlasTextureWidth / kNumPlotsX;
	static const int kPlotHeight = kAtlasTextureHeight / kNumPlotsY;

	GrContext* fContext; // pointer back to owning context
	SkAutoTDelete<GrAtlas> fAtlas; // TODO: could lazily allocate

	// We cache this information here (rather then, say, on the owning picture)
	// because we want to be able to clean it up as needed (e.g., if a picture
	// is leaked and never cleans itself up we still want to be able to
	// remove the GrPictureInfo once its layers are purged from all the atlas
	// plots).
	SkTDynamicHash<GrPictureInfo, uint32_t> fPictureHash;

	SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key> fLayerHash;

	SkMessageBus<GrPictureDeletedMessage>::Inbox fPictDeletionInbox;

	SkAutoTUnref<SkPicture::DeletionListener> fDeletionListener;

	// This implements a plot-centric locking mechanism (since the atlas
	// backing texture is always locked). Each layer that is locked (i.e.,
	// needed for the current rendering) in a plot increments the plot lock
	// count for that plot. Similarly, once a rendering is complete all the
	// layers used in it decrement the lock count for the used plots.
	// Plots with a 0 lock count are open for recycling/purging.
	int fPlotLocks[kNumPlotsX * kNumPlotsY];

	void initAtlas();
	GrCachedLayer* createLayer(const SkPicture* picture, int start, int stop, const SkMatrix& ctm);

	// Remove all the layers (and unlock any resources) associated with 'pictureID'
	void purge(uint32_t pictureID);

	static bool PlausiblyAtlasable(int width, int height) {
	return width <= kPlotWidth && height <= kPlotHeight;
	}

	// Try to find a purgeable plot and clear it out. Return true if a plot
	// was purged; false otherwise.
	bool purgePlot();

	// for testing
	friend class TestingAccess;
	int numLayers() const { return fLayerHash.count(); }
	};

	#endif