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 == plot || 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(uint32_t pictureID, int start, int stop, const SkMatrix& ctm);

            
                GrCachedLayer* findLayerOrCreate(uint32_t pictureID,

            
                                                 int start, int stop,

            
                                                 const SkMatrix& ctm);


                // Inform the cache that layer's cached image is now required.

            
                // Return true if the layer must be re-rendered. Return false if the

            
                // layer was found in the cache and can be reused.

            
                bool lock(GrCachedLayer* layer, const GrTextureDesc& desc, bool dontAtlas);


                // 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(uint32_t pictureID, int start, int stop, const SkMatrix& ctm);


            public:

            
                void purgeAll();


                // 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;

            
                }


                void purgePlot(GrPlot* plot);


                // 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 == plot \|\| 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(uint32_t pictureID, int start, int stop, const SkMatrix& ctm);
	GrCachedLayer* findLayerOrCreate(uint32_t pictureID,
	int start, int stop,
	const SkMatrix& ctm);

	// Inform the cache that layer's cached image is now required.
	// Return true if the layer must be re-rendered. Return false if the
	// layer was found in the cache and can be reused.
	bool lock(GrCachedLayer* layer, const GrTextureDesc& desc, bool dontAtlas);

	// 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(uint32_t pictureID, int start, int stop, const SkMatrix& ctm);

	public:
	void purgeAll();

	// 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;
	}

	void purgePlot(GrPlot* plot);

	// 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