1 /*
2  * Copyright 2010 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef GrContext_DEFINED
9 #define GrContext_DEFINED
10 
11 #include "GrCaps.h"
12 #include "GrClip.h"
13 #include "GrColor.h"
14 #include "GrPaint.h"
15 #include "GrRenderTarget.h"
16 #include "GrTextureProvider.h"
17 #include "SkMatrix.h"
18 #include "SkPathEffect.h"
19 #include "SkTypes.h"
20 #include "../private/GrAuditTrail.h"
21 #include "../private/GrSingleOwner.h"
22 #include "../private/SkMutex.h"
23 
24 struct GrBatchAtlasConfig;
25 class GrBatchFontCache;
26 struct GrContextOptions;
27 class GrDrawingManager;
28 class GrDrawContext;
29 class GrDrawTarget;
30 class GrFragmentProcessor;
31 class GrGpu;
32 class GrIndexBuffer;
33 class GrLayerCache;
34 class GrOvalRenderer;
35 class GrPath;
36 class GrPipelineBuilder;
37 class GrResourceEntry;
38 class GrResourceCache;
39 class GrResourceProvider;
40 class GrTestTarget;
41 class GrTextBlobCache;
42 class GrTextContext;
43 class GrTextureParams;
44 class GrVertexBuffer;
45 class GrStrokeInfo;
46 class GrSwizzle;
47 class SkTraceMemoryDump;
48 
49 class SK_API GrContext : public SkRefCnt {
50 public:
51     /**
52      * Creates a GrContext for a backend context.
53      */
54     static GrContext* Create(GrBackend, GrBackendContext, const GrContextOptions& options);
55     static GrContext* Create(GrBackend, GrBackendContext);
56 
57     /**
58      * Only defined in test apps.
59      */
60     static GrContext* CreateMockContext();
61 
62     virtual ~GrContext();
63 
64     /**
65      * The GrContext normally assumes that no outsider is setting state
66      * within the underlying 3D API's context/device/whatever. This call informs
67      * the context that the state was modified and it should resend. Shouldn't
68      * be called frequently for good performance.
69      * The flag bits, state, is dpendent on which backend is used by the
70      * context, either GL or D3D (possible in future).
71      */
72     void resetContext(uint32_t state = kAll_GrBackendState);
73 
74     /**
75      * Callback function to allow classes to cleanup on GrContext destruction.
76      * The 'info' field is filled in with the 'info' passed to addCleanUp.
77      */
78     typedef void (*PFCleanUpFunc)(const GrContext* context, void* info);
79 
80     /**
81      * Add a function to be called from within GrContext's destructor.
82      * This gives classes a chance to free resources held on a per context basis.
83      * The 'info' parameter will be stored and passed to the callback function.
84      */
addCleanUp(PFCleanUpFunc cleanUp,void * info)85     void addCleanUp(PFCleanUpFunc cleanUp, void* info) {
86         CleanUpData* entry = fCleanUpData.push();
87 
88         entry->fFunc = cleanUp;
89         entry->fInfo = info;
90     }
91 
92     /**
93      * Abandons all GPU resources and assumes the underlying backend 3D API
94      * context is not longer usable. Call this if you have lost the associated
95      * GPU context, and thus internal texture, buffer, etc. references/IDs are
96      * now invalid. Should be called even when GrContext is no longer going to
97      * be used for two reasons:
98      *  1) ~GrContext will not try to free the objects in the 3D API.
99      *  2) Any GrGpuResources created by this GrContext that outlive
100      *     will be marked as invalid (GrGpuResource::wasDestroyed()) and
101      *     when they're destroyed no 3D API calls will be made.
102      * Content drawn since the last GrContext::flush() may be lost. After this
103      * function is called the only valid action on the GrContext or
104      * GrGpuResources it created is to destroy them.
105      */
106     void abandonContext();
107 
108     ///////////////////////////////////////////////////////////////////////////
109     // Resource Cache
110 
111     /**
112      *  Return the current GPU resource cache limits.
113      *
114      *  @param maxResources If non-null, returns maximum number of resources that
115      *                      can be held in the cache.
116      *  @param maxResourceBytes If non-null, returns maximum number of bytes of
117      *                          video memory that can be held in the cache.
118      */
119     void getResourceCacheLimits(int* maxResources, size_t* maxResourceBytes) const;
120 
121     /**
122      *  Gets the current GPU resource cache usage.
123      *
124      *  @param resourceCount If non-null, returns the number of resources that are held in the
125      *                       cache.
126      *  @param maxResourceBytes If non-null, returns the total number of bytes of video memory held
127      *                          in the cache.
128      */
129     void getResourceCacheUsage(int* resourceCount, size_t* resourceBytes) const;
130 
131     /**
132      *  Specify the GPU resource cache limits. If the current cache exceeds either
133      *  of these, it will be purged (LRU) to keep the cache within these limits.
134      *
135      *  @param maxResources The maximum number of resources that can be held in
136      *                      the cache.
137      *  @param maxResourceBytes The maximum number of bytes of video memory
138      *                          that can be held in the cache.
139      */
140     void setResourceCacheLimits(int maxResources, size_t maxResourceBytes);
141 
textureProvider()142     GrTextureProvider* textureProvider() { return fTextureProvider; }
textureProvider()143     const GrTextureProvider* textureProvider() const { return fTextureProvider; }
144 
145     /**
146      * Frees GPU created by the context. Can be called to reduce GPU memory
147      * pressure.
148      */
149     void freeGpuResources();
150 
151     /**
152      * Purge all the unlocked resources from the cache.
153      * This entry point is mainly meant for timing texture uploads
154      * and is not defined in normal builds of Skia.
155      */
156     void purgeAllUnlockedResources();
157 
158     /** Access the context capabilities */
caps()159     const GrCaps* caps() const { return fCaps; }
160 
161     /**
162      * Returns the recommended sample count for a render target when using this
163      * context.
164      *
165      * @param  config the configuration of the render target.
166      * @param  dpi the display density in dots per inch.
167      *
168      * @return sample count that should be perform well and have good enough
169      *         rendering quality for the display. Alternatively returns 0 if
170      *         MSAA is not supported or recommended to be used by default.
171      */
172     int getRecommendedSampleCount(GrPixelConfig config, SkScalar dpi) const;
173 
174     /**
175      * Returns a helper object to orchestrate draws.
176      * Callers assume the creation ref of the drawContext
177      * NULL will be returned if the context has been abandoned.
178      *
179      * @param  rt           the render target receiving the draws
180      * @param  surfaceProps the surface properties (mainly defines text drawing)
181      *
182      * @return a draw context
183      */
184     GrDrawContext* drawContext(GrRenderTarget* rt, const SkSurfaceProps* surfaceProps = NULL);
185 
186     ///////////////////////////////////////////////////////////////////////////
187     // Misc.
188 
189     /**
190      * Flags that affect flush() behavior.
191      */
192     enum FlushBits {
193         /**
194          * A client may reach a point where it has partially rendered a frame
195          * through a GrContext that it knows the user will never see. This flag
196          * causes the flush to skip submission of deferred content to the 3D API
197          * during the flush.
198          */
199         kDiscard_FlushBit                    = 0x2,
200     };
201 
202     /**
203      * Call to ensure all drawing to the context has been issued to the
204      * underlying 3D API.
205      * @param flagsBitfield     flags that control the flushing behavior. See
206      *                          FlushBits.
207      */
208     void flush(int flagsBitfield = 0);
209 
flushIfNecessary()210     void flushIfNecessary() {
211         if (fFlushToReduceCacheSize || this->caps()->immediateFlush()) {
212             this->flush();
213         }
214     }
215 
216    /**
217     * These flags can be used with the read/write pixels functions below.
218     */
219     enum PixelOpsFlags {
220         /** The GrContext will not be flushed before the surface read or write. This means that
221             the read or write may occur before previous draws have executed. */
222         kDontFlush_PixelOpsFlag = 0x1,
223         /** Any surface writes should be flushed to the backend 3D API after the surface operation
224             is complete */
225         kFlushWrites_PixelOp = 0x2,
226         /** The src for write or dst read is unpremultiplied. This is only respected if both the
227             config src and dst configs are an RGBA/BGRA 8888 format. */
228         kUnpremul_PixelOpsFlag  = 0x4,
229     };
230 
231     /**
232      * Reads a rectangle of pixels from a surface.
233      * @param surface       the surface to read from.
234      * @param left          left edge of the rectangle to read (inclusive)
235      * @param top           top edge of the rectangle to read (inclusive)
236      * @param width         width of rectangle to read in pixels.
237      * @param height        height of rectangle to read in pixels.
238      * @param config        the pixel config of the destination buffer
239      * @param buffer        memory to read the rectangle into.
240      * @param rowBytes      number of bytes bewtween consecutive rows. Zero means rows are tightly
241      *                      packed.
242      * @param pixelOpsFlags see PixelOpsFlags enum above.
243      *
244      * @return true if the read succeeded, false if not. The read can fail because of an unsupported
245      *         pixel configs
246      */
247     bool readSurfacePixels(GrSurface* surface,
248                            int left, int top, int width, int height,
249                            GrPixelConfig config, void* buffer,
250                            size_t rowBytes = 0,
251                            uint32_t pixelOpsFlags = 0);
252 
253     /**
254      * Writes a rectangle of pixels to a surface.
255      * @param surface       the surface to write to.
256      * @param left          left edge of the rectangle to write (inclusive)
257      * @param top           top edge of the rectangle to write (inclusive)
258      * @param width         width of rectangle to write in pixels.
259      * @param height        height of rectangle to write in pixels.
260      * @param config        the pixel config of the source buffer
261      * @param buffer        memory to read pixels from
262      * @param rowBytes      number of bytes between consecutive rows. Zero
263      *                      means rows are tightly packed.
264      * @param pixelOpsFlags see PixelOpsFlags enum above.
265      * @return true if the write succeeded, false if not. The write can fail because of an
266      *         unsupported combination of surface and src configs.
267      */
268     bool writeSurfacePixels(GrSurface* surface,
269                             int left, int top, int width, int height,
270                             GrPixelConfig config, const void* buffer,
271                             size_t rowBytes,
272                             uint32_t pixelOpsFlags = 0);
273 
274     /**
275      * Copies a rectangle of texels from src to dst.
276      * bounds.
277      * @param dst           the surface to copy to.
278      * @param src           the surface to copy from.
279      * @param srcRect       the rectangle of the src that should be copied.
280      * @param dstPoint      the translation applied when writing the srcRect's pixels to the dst.
281      */
282     bool copySurface(GrSurface* dst,
283                      GrSurface* src,
284                      const SkIRect& srcRect,
285                      const SkIPoint& dstPoint);
286 
287     /** Helper that copies the whole surface but fails when the two surfaces are not identically
288         sized. */
copySurface(GrSurface * dst,GrSurface * src)289     bool copySurface(GrSurface* dst, GrSurface* src) {
290         return this->copySurface(dst, src, SkIRect::MakeWH(dst->width(), dst->height()),
291                                  SkIPoint::Make(0,0));
292     }
293 
294     /**
295      * After this returns any pending writes to the surface will have been issued to the backend 3D API.
296      */
297     void flushSurfaceWrites(GrSurface* surface);
298 
299     /**
300      * Finalizes all pending reads and writes to the surface and also performs an MSAA resolve
301      * if necessary.
302      *
303      * It is not necessary to call this before reading the render target via Skia/GrContext.
304      * GrContext will detect when it must perform a resolve before reading pixels back from the
305      * surface or using it as a texture.
306      */
307     void prepareSurfaceForExternalIO(GrSurface*);
308 
309     /**
310      * An ID associated with this context, guaranteed to be unique.
311      */
uniqueID()312     uint32_t uniqueID() { return fUniqueID; }
313 
314     ///////////////////////////////////////////////////////////////////////////
315     // Functions intended for internal use only.
getGpu()316     GrGpu* getGpu() { return fGpu; }
getGpu()317     const GrGpu* getGpu() const { return fGpu; }
getBatchFontCache()318     GrBatchFontCache* getBatchFontCache() { return fBatchFontCache; }
getLayerCache()319     GrLayerCache* getLayerCache() { return fLayerCache.get(); }
getTextBlobCache()320     GrTextBlobCache* getTextBlobCache() { return fTextBlobCache; }
321     bool abandoned() const;
resourceProvider()322     GrResourceProvider* resourceProvider() { return fResourceProvider; }
resourceProvider()323     const GrResourceProvider* resourceProvider() const { return fResourceProvider; }
getResourceCache()324     GrResourceCache* getResourceCache() { return fResourceCache; }
325 
326     // Called by tests that draw directly to the context via GrDrawTarget
327     void getTestTarget(GrTestTarget*, GrRenderTarget* rt);
328 
329     /** Reset GPU stats */
330     void resetGpuStats() const ;
331 
332     /** Prints cache stats to the string if GR_CACHE_STATS == 1. */
333     void dumpCacheStats(SkString*) const;
334     void dumpCacheStatsKeyValuePairs(SkTArray<SkString>* keys, SkTArray<double>* values) const;
335     void printCacheStats() const;
336 
337     /** Prints GPU stats to the string if GR_GPU_STATS == 1. */
338     void dumpGpuStats(SkString*) const;
339     void dumpGpuStatsKeyValuePairs(SkTArray<SkString>* keys, SkTArray<double>* values) const;
340     void printGpuStats() const;
341 
342     /** Specify the TextBlob cache limit. If the current cache exceeds this limit it will purge.
343         this is for testing only */
344     void setTextBlobCacheLimit_ForTesting(size_t bytes);
345 
346     /** Specify the sizes of the GrAtlasTextContext atlases.  The configs pointer below should be
347         to an array of 3 entries */
348     void setTextContextAtlasSizes_ForTesting(const GrBatchAtlasConfig* configs);
349 
350     /** Enumerates all cached GPU resources and dumps their memory to traceMemoryDump. */
351     void dumpMemoryStatistics(SkTraceMemoryDump* traceMemoryDump) const;
352 
353     /** Get pointer to atlas texture for given mask format */
354     GrTexture* getFontAtlasTexture(GrMaskFormat format);
355 
getAuditTrail()356     GrAuditTrail* getAuditTrail() { return &fAuditTrail; }
357 
358     /** This is only useful for debug purposes */
359     SkDEBUGCODE(GrSingleOwner* debugSingleOwner() const { return &fSingleOwner; } )
360 
361 private:
362     GrGpu*                          fGpu;
363     const GrCaps*                   fCaps;
364     GrResourceCache*                fResourceCache;
365     // this union exists because the inheritance of GrTextureProvider->GrResourceProvider
366     // is in a private header.
367     union {
368         GrResourceProvider*         fResourceProvider;
369         GrTextureProvider*          fTextureProvider;
370     };
371 
372     GrBatchFontCache*               fBatchFontCache;
373     SkAutoTDelete<GrLayerCache>     fLayerCache;
374     SkAutoTDelete<GrTextBlobCache>  fTextBlobCache;
375 
376     // Set by OverbudgetCB() to request that GrContext flush before exiting a draw.
377     bool                            fFlushToReduceCacheSize;
378     bool                            fDidTestPMConversions;
379     int                             fPMToUPMConversion;
380     int                             fUPMToPMConversion;
381     // The sw backend may call GrContext::readSurfacePixels on multiple threads
382     // We may transfer the responsibilty for using a mutex to the sw backend
383     // when there are fewer code paths that lead to a readSurfacePixels call
384     // from the sw backend. readSurfacePixels is reentrant in one case - when performing
385     // the PM conversions test. To handle this we do the PM conversions test outside
386     // of fReadPixelsMutex and use a separate mutex to guard it. When it re-enters
387     // readSurfacePixels it will grab fReadPixelsMutex and release it before the outer
388     // readSurfacePixels proceeds to grab it.
389     // TODO: Stop pretending to make GrContext thread-safe for sw rasterization and provide
390     // a mechanism to make a SkPicture safe for multithreaded sw rasterization.
391     SkMutex                         fReadPixelsMutex;
392     SkMutex                         fTestPMConversionsMutex;
393 
394     // In debug builds we guard against improper thread handling
395     // This guard is passed to the GrDrawingManager and, from there to all the
396     // GrDrawContexts.  It is also passed to the GrTextureProvider and SkGpuDevice.
397     mutable GrSingleOwner fSingleOwner;
398 
399     struct CleanUpData {
400         PFCleanUpFunc fFunc;
401         void*         fInfo;
402     };
403 
404     SkTDArray<CleanUpData>          fCleanUpData;
405 
406     const uint32_t                  fUniqueID;
407 
408     SkAutoTDelete<GrDrawingManager> fDrawingManager;
409 
410     GrAuditTrail                    fAuditTrail;
411 
412     // TODO: have the CMM use drawContexts and rm this friending
413     friend class GrClipMaskManager; // the CMM is friended just so it can call 'drawingManager'
414     friend class GrDrawingManager;  // for access to drawingManager for ProgramUnitTest
drawingManager()415     GrDrawingManager* drawingManager() { return fDrawingManager; }
416 
417     GrContext(); // init must be called after the constructor.
418     bool init(GrBackend, GrBackendContext, const GrContextOptions& options);
419 
420     void initMockContext();
421     void initCommon(const GrContextOptions&);
422 
423     /**
424      * These functions create premul <-> unpremul effects if it is possible to generate a pair
425      * of effects that make a readToUPM->writeToPM->readToUPM cycle invariant. Otherwise, they
426      * return NULL. They also can perform a swizzle as part of the draw.
427      */
428     const GrFragmentProcessor* createPMToUPMEffect(GrTexture*, const GrSwizzle&,
429                                                    const SkMatrix&) const;
430     const GrFragmentProcessor* createUPMToPMEffect(GrTexture*, const GrSwizzle&,
431                                                    const SkMatrix&) const;
432     /** Called before either of the above two functions to determine the appropriate fragment
433         processors for conversions. This must be called by readSurfacePixels before a mutex is
434         taken, since testingvPM conversions itself will call readSurfacePixels */
435     void testPMConversionsIfNecessary(uint32_t flags);
436     /** Returns true if we've already determined that createPMtoUPMEffect and createUPMToPMEffect
437         will fail. In such cases fall back to SW conversion. */
438     bool didFailPMUPMConversionTest() const;
439 
440     /**
441      *  This callback allows the resource cache to callback into the GrContext
442      *  when the cache is still over budget after a purge.
443      */
444     static void OverBudgetCB(void* data);
445 
446     /**
447      * A callback similar to the above for use by the TextBlobCache
448      * TODO move textblob draw calls below context so we can use the call above.
449      */
450     static void TextBlobCacheOverBudgetCB(void* data);
451 
452     typedef SkRefCnt INHERITED;
453 };
454 
455 #endif
456