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1 /*
2  * Copyright 2015 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 GrContextOptions_DEFINED
9 #define GrContextOptions_DEFINED
10 
11 #include "include/core/SkData.h"
12 #include "include/core/SkString.h"
13 #include "include/core/SkTypes.h"
14 #include "include/gpu/GrDriverBugWorkarounds.h"
15 #include "include/gpu/GrTypes.h"
16 #include "include/gpu/ShaderErrorHandler.h"
17 #include "include/private/gpu/ganesh/GrTypesPriv.h"
18 
19 #include <vector>
20 
21 class SkExecutor;
22 
23 struct SK_API GrContextOptions {
24     enum class Enable {
25         /** Forces an option to be disabled. */
26         kNo,
27         /** Forces an option to be enabled. */
28         kYes,
29         /**
30          * Uses Skia's default behavior, which may use runtime properties (e.g. driver version).
31          */
32         kDefault
33     };
34 
35     enum class ShaderCacheStrategy {
36         kSkSL,
37         kBackendSource,
38         kBackendBinary,
39     };
40 
41     /**
42      * Abstract class which stores Skia data in a cache that persists between sessions. Currently,
43      * Skia stores compiled shader binaries (only when glProgramBinary / glGetProgramBinary are
44      * supported) when provided a persistent cache, but this may extend to other data in the future.
45      */
46     class SK_API PersistentCache {
47     public:
48         virtual ~PersistentCache() = default;
49 
50         /**
51          * Returns the data for the key if it exists in the cache, otherwise returns null.
52          */
53         virtual sk_sp<SkData> load(const SkData& key) = 0;
54 
55         // Placeholder until all clients override the 3-parameter store(), then remove this, and
56         // make that version pure virtual.
storeGrContextOptions57         virtual void store(const SkData& /*key*/, const SkData& /*data*/) { SkASSERT(false); }
58 
59         /**
60          * Stores data in the cache, indexed by key. description provides a human-readable
61          * version of the key.
62          */
storeGrContextOptions63         virtual void store(const SkData& key, const SkData& data, const SkString& /*description*/) {
64             this->store(key, data);
65         }
66 
67     protected:
68         PersistentCache() = default;
69         PersistentCache(const PersistentCache&) = delete;
70         PersistentCache& operator=(const PersistentCache&) = delete;
71     };
72 
73     using ShaderErrorHandler = skgpu::ShaderErrorHandler;
74 
GrContextOptionsGrContextOptions75     GrContextOptions() {}
76 
77     // Suppress prints for the GrContext.
78     bool fSuppressPrints = false;
79 
80     /**
81      * Controls whether we check for GL errors after functions that allocate resources (e.g.
82      * glTexImage2D), at the end of a GPU submission, or checking framebuffer completeness. The
83      * results of shader compilation and program linking are always checked, regardless of this
84      * option. Ignored on backends other than GL.
85      */
86     Enable fSkipGLErrorChecks = Enable::kDefault;
87 
88     /** Overrides: These options override feature detection using backend API queries. These
89         overrides can only reduce the feature set or limits, never increase them beyond the
90         detected values. */
91 
92     int  fMaxTextureSizeOverride = SK_MaxS32;
93 
94     /** the threshold in bytes above which we will use a buffer mapping API to map vertex and index
95         buffers to CPU memory in order to update them.  A value of -1 means the GrContext should
96         deduce the optimal value for this platform. */
97     int  fBufferMapThreshold = -1;
98 
99     /** Default minimum size to use when allocating buffers for uploading data to textures. The
100         larger the value the more uploads can be packed into one buffer, but at the cost of
101         more gpu memory allocated that may not be used. Uploads larger than the minimum will still
102         work by allocating a dedicated buffer. */
103     size_t fMinimumStagingBufferSize = 64 * 1024;
104 
105     /**
106      * Executor to handle threaded work within Ganesh. If this is nullptr, then all work will be
107      * done serially on the main thread. To have worker threads assist with various tasks, set this
108      * to a valid SkExecutor instance. Currently, used for software path rendering, but may be used
109      * for other tasks.
110      */
111     SkExecutor* fExecutor = nullptr;
112 
113     /** Construct mipmaps manually, via repeated downsampling draw-calls. This is used when
114         the driver's implementation (glGenerateMipmap) contains bugs. This requires mipmap
115         level control (ie desktop or ES3). */
116     bool fDoManualMipmapping = false;
117 
118     /**
119      * Disables the use of coverage counting shortcuts to render paths. Coverage counting can cause
120      * artifacts along shared edges if care isn't taken to ensure both contours wind in the same
121      * direction.
122      */
123     // FIXME: Once this is removed from Chrome and Android, rename to fEnable"".
124     bool fDisableCoverageCountingPaths = true;
125 
126     /**
127      * Disables distance field rendering for paths. Distance field computation can be expensive,
128      * and yields no benefit if a path is not rendered multiple times with different transforms.
129      */
130     bool fDisableDistanceFieldPaths = false;
131 
132     /**
133      * If true this allows path mask textures to be cached. This is only really useful if paths
134      * are commonly rendered at the same scale and fractional translation.
135      */
136     bool fAllowPathMaskCaching = true;
137 
138     /**
139      * If true, the GPU will not be used to perform YUV -> RGB conversion when generating
140      * textures from codec-backed images.
141      */
142     bool fDisableGpuYUVConversion = false;
143 
144     /**
145      * The maximum size of cache textures used for Skia's Glyph cache.
146      */
147     size_t fGlyphCacheTextureMaximumBytes = 2048 * 1024 * 4;
148 
149     /**
150      * Below this threshold size in device space distance field fonts won't be used. Distance field
151      * fonts don't support hinting which is more important at smaller sizes.
152      */
153     float fMinDistanceFieldFontSize = 18;
154 
155     /**
156      * Above this threshold size in device space glyphs are drawn as individual paths.
157      */
158 #if defined(SK_BUILD_FOR_ANDROID)
159     float fGlyphsAsPathsFontSize = 384;
160 #elif defined(SK_BUILD_FOR_MAC)
161     float fGlyphsAsPathsFontSize = 256;
162 #else
163     float fGlyphsAsPathsFontSize = 324;
164 #endif
165 
166     /**
167      * Can the glyph atlas use multiple textures. If allowed, the each texture's size is bound by
168      * fGlypheCacheTextureMaximumBytes.
169      */
170     Enable fAllowMultipleGlyphCacheTextures = Enable::kDefault;
171 
172     /**
173      * Bugs on certain drivers cause stencil buffers to leak. This flag causes Skia to avoid
174      * allocating stencil buffers and use alternate rasterization paths, avoiding the leak.
175      */
176     bool fAvoidStencilBuffers = false;
177 
178     /**
179      * Enables driver workaround to use draws instead of HW clears, e.g. glClear on the GL backend.
180      */
181     Enable fUseDrawInsteadOfClear = Enable::kDefault;
182 
183     /**
184      * Allow Ganesh to more aggressively reorder operations to reduce the number of render passes.
185      * Offscreen draws will be done upfront instead of interrupting the main render pass when
186      * possible. May increase VRAM usage, but still observes the resource cache limit.
187      * Enabled by default.
188      */
189     Enable fReduceOpsTaskSplitting = Enable::kDefault;
190 
191     /**
192      * Some ES3 contexts report the ES2 external image extension, but not the ES3 version.
193      * If support for external images is critical, enabling this option will cause Ganesh to limit
194      * shaders to the ES2 shading language in that situation.
195      */
196     bool fPreferExternalImagesOverES3 = false;
197 
198     /**
199      * Disables correctness workarounds that are enabled for particular GPUs, OSes, or drivers.
200      * This does not affect code path choices that are made for perfomance reasons nor does it
201      * override other GrContextOption settings.
202      */
203     bool fDisableDriverCorrectnessWorkarounds = false;
204 
205     /**
206      * Maximum number of GPU programs or pipelines to keep active in the runtime cache.
207      */
208     int fRuntimeProgramCacheSize = 256;
209 
210     /**
211      * Cache in which to store compiled shader binaries between runs.
212      */
213     PersistentCache* fPersistentCache = nullptr;
214 
215     /**
216      * This affects the usage of the PersistentCache. We can cache SkSL, backend source (GLSL), or
217      * backend binaries (GL program binaries). By default we cache binaries, but if the driver's
218      * binary loading/storing is believed to have bugs, this can be limited to caching GLSL.
219      * Caching GLSL strings still saves CPU work when a GL program is created.
220      */
221     ShaderCacheStrategy fShaderCacheStrategy = ShaderCacheStrategy::kBackendBinary;
222 
223     /**
224      * If present, use this object to report shader compilation failures. If not, report failures
225      * via SkDebugf and assert.
226      */
227     ShaderErrorHandler* fShaderErrorHandler = nullptr;
228 
229     /**
230      * Specifies the number of samples Ganesh should use when performing internal draws with MSAA
231      * (hardware capabilities permitting).
232      *
233      * If 0, Ganesh will disable internal code paths that use multisampling.
234      */
235     int  fInternalMultisampleCount = 4;
236 
237     /**
238      * In Skia's vulkan backend a single GrContext submit equates to the submission of a single
239      * primary command buffer to the VkQueue. This value specifies how many vulkan secondary command
240      * buffers we will cache for reuse on a given primary command buffer. A single submit may use
241      * more than this many secondary command buffers, but after the primary command buffer is
242      * finished on the GPU it will only hold on to this many secondary command buffers for reuse.
243      *
244      * A value of -1 means we will pick a limit value internally.
245      */
246     int fMaxCachedVulkanSecondaryCommandBuffers = -1;
247 
248     /**
249      * If true, the caps will never support mipmaps.
250      */
251     bool fSuppressMipmapSupport = false;
252 
253     /**
254      * If true, the TessellationPathRenderer will not be used for path rendering.
255      * If false, will fallback to any driver workarounds, if set.
256      */
257     bool fDisableTessellationPathRenderer = false;
258 
259     /**
260      * If true, and if supported, enables hardware tessellation in the caps.
261      * DEPRECATED: This value is ignored; experimental hardware tessellation is always disabled.
262      */
263     bool fEnableExperimentalHardwareTessellation = false;
264 
265     /**
266      * If true, then add 1 pixel padding to all glyph masks in the atlas to support bi-lerp
267      * rendering of all glyphs. This must be set to true to use Slugs.
268      */
269     bool fSupportBilerpFromGlyphAtlas = false;
270 
271     /**
272      * Uses a reduced variety of shaders. May perform less optimally in steady state but can reduce
273      * jank due to shader compilations.
274      */
275     bool fReducedShaderVariations = false;
276 
277     /**
278      * If true, then allow to enable MSAA on new Intel GPUs.
279      */
280     bool fAllowMSAAOnNewIntel = false;
281 
282     /**
283      * Currently on ARM Android we disable the use of GL TexStorage because of memory regressions.
284      * However, some clients may still want to use TexStorage. For example, TexStorage support is
285      * required for creating protected textures.
286      *
287      * This flag has no impact on non GL backends.
288      */
289     bool fAlwaysUseTexStorageWhenAvailable = false;
290 
291     /**
292      * Optional callback that can be passed into the GrDirectContext which will be called when the
293      * GrDirectContext is about to be destroyed. When this call is made, it will be safe for the
294      * client to delete the GPU backend context that is backing the GrDirectContext. The
295      * GrDirectContextDestroyedContext will be passed back to the client in the callback.
296      */
297     GrDirectContextDestroyedContext fContextDeleteContext = nullptr;
298     GrDirectContextDestroyedProc fContextDeleteProc = nullptr;
299 
300 #if defined(GR_TEST_UTILS)
301     /**
302      * Private options that are only meant for testing within Skia's tools.
303      */
304 
305     /**
306      * Testing-only mode to exercise allocation failures in the flush-time callback objects.
307      * For now it only simulates allocation failure during the preFlush callback.
308      */
309     bool fFailFlushTimeCallbacks = false;
310 
311     /**
312      * Prevents use of dual source blending, to test that all xfer modes work correctly without it.
313      */
314     bool fSuppressDualSourceBlending = false;
315 
316     /**
317      * Prevents the use of non-coefficient-based blend equations, for testing dst reads, barriers,
318      * and in-shader blending.
319      */
320     bool fSuppressAdvancedBlendEquations = false;
321 
322     /**
323      * Prevents the use of framebuffer fetches, for testing dst reads and texture barriers.
324      */
325     bool fSuppressFramebufferFetch = false;
326 
327     /**
328      * If true, then all paths are processed as if "setIsVolatile" had been called.
329      */
330     bool fAllPathsVolatile = false;
331 
332     /**
333      * Render everything in wireframe
334      */
335     bool fWireframeMode = false;
336 
337     /**
338      * Enforces clearing of all textures when they're created.
339      */
340     bool fClearAllTextures = false;
341 
342     /**
343      * Randomly generate a (false) GL_OUT_OF_MEMORY error
344      */
345     bool fRandomGLOOM = false;
346 
347     /**
348      * Force off support for write/transfer pixels row bytes in caps.
349      */
350     bool fDisallowWriteAndTransferPixelRowBytes = false;
351 
352     /**
353      * Include or exclude specific GPU path renderers.
354      */
355     GpuPathRenderers fGpuPathRenderers = GpuPathRenderers::kDefault;
356 
357     /**
358      * Specify the GPU resource cache limit. Equivalent to calling `setResourceCacheLimit` on the
359      * context at construction time.
360      *
361      * A value of -1 means use the default limit value.
362      */
363     int fResourceCacheLimitOverride = -1;
364 
365     /**
366      * Maximum width and height of internal texture atlases.
367      */
368     int  fMaxTextureAtlasSize = 2048;
369 #endif
370 
371     GrDriverBugWorkarounds fDriverBugWorkarounds;
372 };
373 
374 #endif
375