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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 #if defined(SK_GANESH)
24 struct SK_API GrContextOptions {
25     enum class Enable {
26         /** Forces an option to be disabled. */
27         kNo,
28         /** Forces an option to be enabled. */
29         kYes,
30         /**
31          * Uses Skia's default behavior, which may use runtime properties (e.g. driver version).
32          */
33         kDefault
34     };
35 
36     enum class ShaderCacheStrategy {
37         kSkSL,
38         kBackendSource,
39         kBackendBinary,
40     };
41 
42     /**
43      * Abstract class which stores Skia data in a cache that persists between sessions. Currently,
44      * Skia stores compiled shader binaries (only when glProgramBinary / glGetProgramBinary are
45      * supported) when provided a persistent cache, but this may extend to other data in the future.
46      */
47     class SK_API PersistentCache {
48     public:
49         virtual ~PersistentCache() = default;
50 
51         /**
52          * Returns the data for the key if it exists in the cache, otherwise returns null.
53          */
54         virtual sk_sp<SkData> load(const SkData& key) = 0;
55 
56         // Placeholder until all clients override the 3-parameter store(), then remove this, and
57         // make that version pure virtual.
storeGrContextOptions58         virtual void store(const SkData& /*key*/, const SkData& /*data*/) { SkASSERT(false); }
59 
60         /**
61          * Stores data in the cache, indexed by key. description provides a human-readable
62          * version of the key.
63          */
storeGrContextOptions64         virtual void store(const SkData& key, const SkData& data, const SkString& /*description*/) {
65             this->store(key, data);
66         }
67 
68     protected:
69         PersistentCache() = default;
70         PersistentCache(const PersistentCache&) = delete;
71         PersistentCache& operator=(const PersistentCache&) = delete;
72     };
73 
74     using ShaderErrorHandler = skgpu::ShaderErrorHandler;
75 
GrContextOptionsGrContextOptions76     GrContextOptions() {}
77 
78     // Suppress prints for the GrContext.
79     bool fSuppressPrints = false;
80 
81     /**
82      * Controls whether we check for GL errors after functions that allocate resources (e.g.
83      * glTexImage2D), at the end of a GPU submission, or checking framebuffer completeness. The
84      * results of shader compilation and program linking are always checked, regardless of this
85      * option. Ignored on backends other than GL.
86      */
87     Enable fSkipGLErrorChecks = Enable::kDefault;
88 
89     /** Overrides: These options override feature detection using backend API queries. These
90         overrides can only reduce the feature set or limits, never increase them beyond the
91         detected values. */
92 
93     int  fMaxTextureSizeOverride = SK_MaxS32;
94 
95     /** the threshold in bytes above which we will use a buffer mapping API to map vertex and index
96         buffers to CPU memory in order to update them.  A value of -1 means the GrContext should
97         deduce the optimal value for this platform. */
98     int  fBufferMapThreshold = -1;
99 
100     /**
101      * Executor to handle threaded work within Ganesh. If this is nullptr, then all work will be
102      * done serially on the main thread. To have worker threads assist with various tasks, set this
103      * to a valid SkExecutor instance. Currently, used for software path rendering, but may be used
104      * for other tasks.
105      */
106     SkExecutor* fExecutor = nullptr;
107 
108     /** Construct mipmaps manually, via repeated downsampling draw-calls. This is used when
109         the driver's implementation (glGenerateMipmap) contains bugs. This requires mipmap
110         level control (ie desktop or ES3). */
111     bool fDoManualMipmapping = false;
112 
113     /**
114      * Disables the use of coverage counting shortcuts to render paths. Coverage counting can cause
115      * artifacts along shared edges if care isn't taken to ensure both contours wind in the same
116      * direction.
117      */
118     // FIXME: Once this is removed from Chrome and Android, rename to fEnable"".
119     bool fDisableCoverageCountingPaths = true;
120 
121     /**
122      * Disables distance field rendering for paths. Distance field computation can be expensive,
123      * and yields no benefit if a path is not rendered multiple times with different transforms.
124      */
125     bool fDisableDistanceFieldPaths = false;
126 
127     /**
128      * If true this allows path mask textures to be cached. This is only really useful if paths
129      * are commonly rendered at the same scale and fractional translation.
130      */
131     bool fAllowPathMaskCaching = true;
132 
133     /**
134      * If true, the GPU will not be used to perform YUV -> RGB conversion when generating
135      * textures from codec-backed images.
136      */
137     bool fDisableGpuYUVConversion = false;
138 
139     /**
140      * The maximum size of cache textures used for Skia's Glyph cache.
141      */
142     size_t fGlyphCacheTextureMaximumBytes = 2048 * 1024 * 4;
143 
144     /**
145      * Below this threshold size in device space distance field fonts won't be used. Distance field
146      * fonts don't support hinting which is more important at smaller sizes.
147      */
148     float fMinDistanceFieldFontSize = 18;
149 
150     /**
151      * Above this threshold size in device space glyphs are drawn as individual paths.
152      */
153 #if defined(SK_BUILD_FOR_ANDROID)
154     float fGlyphsAsPathsFontSize = 384;
155 #elif defined(SK_BUILD_FOR_MAC)
156     float fGlyphsAsPathsFontSize = 256;
157 #else
158     float fGlyphsAsPathsFontSize = 324;
159 #endif
160 
161     /**
162      * Can the glyph atlas use multiple textures. If allowed, the each texture's size is bound by
163      * fGlypheCacheTextureMaximumBytes.
164      */
165     Enable fAllowMultipleGlyphCacheTextures = Enable::kDefault;
166 
167     /**
168      * Bugs on certain drivers cause stencil buffers to leak. This flag causes Skia to avoid
169      * allocating stencil buffers and use alternate rasterization paths, avoiding the leak.
170      */
171     bool fAvoidStencilBuffers = false;
172 
173     /**
174      * Enables driver workaround to use draws instead of HW clears, e.g. glClear on the GL backend.
175      */
176     Enable fUseDrawInsteadOfClear = Enable::kDefault;
177 
178     /**
179      * Allow Ganesh to more aggressively reorder operations to reduce the number of render passes.
180      * Offscreen draws will be done upfront instead of interrupting the main render pass when
181      * possible. May increase VRAM usage, but still observes the resource cache limit.
182      * Enabled by default.
183      */
184     Enable fReduceOpsTaskSplitting = Enable::kDefault;
185 
186     /**
187      * Some ES3 contexts report the ES2 external image extension, but not the ES3 version.
188      * If support for external images is critical, enabling this option will cause Ganesh to limit
189      * shaders to the ES2 shading language in that situation.
190      */
191     bool fPreferExternalImagesOverES3 = false;
192 
193     /**
194      * Disables correctness workarounds that are enabled for particular GPUs, OSes, or drivers.
195      * This does not affect code path choices that are made for perfomance reasons nor does it
196      * override other GrContextOption settings.
197      */
198     bool fDisableDriverCorrectnessWorkarounds = false;
199 
200     /**
201      * Maximum number of GPU programs or pipelines to keep active in the runtime cache.
202      */
203     int fRuntimeProgramCacheSize = 256;
204 
205     /**
206      * Cache in which to store compiled shader binaries between runs.
207      */
208     PersistentCache* fPersistentCache = nullptr;
209 
210     /**
211      * This affects the usage of the PersistentCache. We can cache SkSL, backend source (GLSL), or
212      * backend binaries (GL program binaries). By default we cache binaries, but if the driver's
213      * binary loading/storing is believed to have bugs, this can be limited to caching GLSL.
214      * Caching GLSL strings still saves CPU work when a GL program is created.
215      */
216     ShaderCacheStrategy fShaderCacheStrategy = ShaderCacheStrategy::kBackendBinary;
217 
218     /**
219      * If present, use this object to report shader compilation failures. If not, report failures
220      * via SkDebugf and assert.
221      */
222     ShaderErrorHandler* fShaderErrorHandler = nullptr;
223 
224     /**
225      * Specifies the number of samples Ganesh should use when performing internal draws with MSAA
226      * (hardware capabilities permitting).
227      *
228      * If 0, Ganesh will disable internal code paths that use multisampling.
229      */
230     int  fInternalMultisampleCount = 4;
231 
232     /**
233      * In Skia's vulkan backend a single GrContext submit equates to the submission of a single
234      * primary command buffer to the VkQueue. This value specifies how many vulkan secondary command
235      * buffers we will cache for reuse on a given primary command buffer. A single submit may use
236      * more than this many secondary command buffers, but after the primary command buffer is
237      * finished on the GPU it will only hold on to this many secondary command buffers for reuse.
238      *
239      * A value of -1 means we will pick a limit value internally.
240      */
241     int fMaxCachedVulkanSecondaryCommandBuffers = -1;
242 
243     /**
244      * If true, the caps will never support mipmaps.
245      */
246     bool fSuppressMipmapSupport = false;
247 
248     /**
249      * If true, the TessellationPathRenderer will not be used for path rendering.
250      * If false, will fallback to any driver workarounds, if set.
251      */
252     bool fDisableTessellationPathRenderer = false;
253 
254     /**
255      * If true, and if supported, enables hardware tessellation in the caps.
256      * DEPRECATED: This value is ignored; experimental hardware tessellation is always disabled.
257      */
258     bool fEnableExperimentalHardwareTessellation = false;
259 
260     /**
261      * If true, then add 1 pixel padding to all glyph masks in the atlas to support bi-lerp
262      * rendering of all glyphs. This must be set to true to use Slugs.
263      */
264     #if defined(SK_EXPERIMENTAL_SIMULATE_DRAWGLYPHRUNLIST_WITH_SLUG) || \
265         defined(SK_EXPERIMENTAL_SIMULATE_DRAWGLYPHRUNLIST_WITH_SLUG_SERIALIZE) || \
266         defined(SK_EXPERIMENTAL_SIMULATE_DRAWGLYPHRUNLIST_WITH_SLUG_STRIKE_SERIALIZE)
267     bool fSupportBilerpFromGlyphAtlas = true;
268     #else
269     bool fSupportBilerpFromGlyphAtlas = false;
270     #endif
271 
272     /**
273      * Uses a reduced variety of shaders. May perform less optimally in steady state but can reduce
274      * jank due to shader compilations.
275      */
276     bool fReducedShaderVariations = false;
277 
278     /**
279      * If true, then allow to enable MSAA on new Intel GPUs.
280      */
281     bool fAllowMSAAOnNewIntel = false;
282 
283     /**
284      * Currently on ARM Android we disable the use of GL TexStorage because of memory regressions.
285      * However, some clients may still want to use TexStorage. For example, TexStorage support is
286      * required for creating protected textures.
287      *
288      * This flag has no impact on non GL backends.
289      */
290     bool fAlwaysUseTexStorageWhenAvailable = false;
291 
292     /**
293      * Optional callback that can be passed into the GrDirectContext which will be called when the
294      * GrDirectContext is about to be destroyed. When this call is made, it will be safe for the
295      * client to delete the GPU backend context that is backing the GrDirectContext. The
296      * GrDirectContextDestroyedContext will be passed back to the client in the callback.
297      */
298     GrDirectContextDestroyedContext fContextDeleteContext = nullptr;
299     GrDirectContextDestroyedProc fContextDeleteProc = nullptr;
300 
301 #if GR_TEST_UTILS
302     /**
303      * Private options that are only meant for testing within Skia's tools.
304      */
305 
306     /**
307      * Testing-only mode to exercise allocation failures in the flush-time callback objects.
308      * For now it only simulates allocation failure during the preFlush callback.
309      */
310     bool fFailFlushTimeCallbacks = false;
311 
312     /**
313      * Prevents use of dual source blending, to test that all xfer modes work correctly without it.
314      */
315     bool fSuppressDualSourceBlending = false;
316 
317     /**
318      * Prevents the use of non-coefficient-based blend equations, for testing dst reads, barriers,
319      * and in-shader blending.
320      */
321     bool fSuppressAdvancedBlendEquations = false;
322 
323     /**
324      * Prevents the use of framebuffer fetches, for testing dst reads and texture barriers.
325      */
326     bool fSuppressFramebufferFetch = false;
327 
328     /**
329      * If true, then all paths are processed as if "setIsVolatile" had been called.
330      */
331     bool fAllPathsVolatile = false;
332 
333     /**
334      * Render everything in wireframe
335      */
336     bool fWireframeMode = false;
337 
338     /**
339      * Enforces clearing of all textures when they're created.
340      */
341     bool fClearAllTextures = false;
342 
343     /**
344      * Randomly generate a (false) GL_OUT_OF_MEMORY error
345      */
346     bool fRandomGLOOM = false;
347 
348     /**
349      * Force off support for write/transfer pixels row bytes in caps.
350      */
351     bool fDisallowWriteAndTransferPixelRowBytes = false;
352 
353     /**
354      * Include or exclude specific GPU path renderers.
355      */
356     GpuPathRenderers fGpuPathRenderers = GpuPathRenderers::kDefault;
357 
358     /**
359      * Specify the GPU resource cache limit. Equivalent to calling `setResourceCacheLimit` on the
360      * context at construction time.
361      *
362      * A value of -1 means use the default limit value.
363      */
364     int fResourceCacheLimitOverride = -1;
365 
366     /**
367      * Maximum width and height of internal texture atlases.
368      */
369     int  fMaxTextureAtlasSize = 2048;
370 #endif
371 
372     GrDriverBugWorkarounds fDriverBugWorkarounds;
373 };
374 #else
375 struct GrContextOptions {
376     struct PersistentCache {};
377 };
378 #endif
379 
380 #endif
381