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ShaderPlayground / deps / glfw / src / context.c
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1//========================================================================
2// GLFW 3.3 - www.glfw.org
3//------------------------------------------------------------------------
4// Copyright (c) 2002-2006 Marcus Geelnard
5// Copyright (c) 2006-2016 Camilla Löwy <elmindreda@glfw.org>
6//
7// This software is provided 'as-is', without any express or implied
8// warranty. In no event will the authors be held liable for any damages
9// arising from the use of this software.
10//
11// Permission is granted to anyone to use this software for any purpose,
12// including commercial applications, and to alter it and redistribute it
13// freely, subject to the following restrictions:
14//
15// 1. The origin of this software must not be misrepresented; you must not
16// claim that you wrote the original software. If you use this software
17// in a product, an acknowledgment in the product documentation would
18// be appreciated but is not required.
19//
20// 2. Altered source versions must be plainly marked as such, and must not
21// be misrepresented as being the original software.
22//
23// 3. This notice may not be removed or altered from any source
24// distribution.
25//
26//========================================================================
27// Please use C89 style variable declarations in this file because VS 2010
28//========================================================================
29
30#include "internal.h"
31
32#include <assert.h>
33#include <stdio.h>
34#include <string.h>
35#include <limits.h>
36#include <stdio.h>
37
38
39//////////////////////////////////////////////////////////////////////////
40////// GLFW internal API //////
41//////////////////////////////////////////////////////////////////////////
42
43// Checks whether the desired context attributes are valid
44//
45// This function checks things like whether the specified client API version
46// exists and whether all relevant options have supported and non-conflicting
47// values
48//
49GLFWbool _glfwIsValidContextConfig(const _GLFWctxconfig* ctxconfig)
50{
51 if (ctxconfig->share)
52 {
53 if (ctxconfig->client == GLFW_NO_API ||
54 ctxconfig->share->context.client == GLFW_NO_API)
55 {
56 _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
57 return GLFW_FALSE;
58 }
59 }
60
61 if (ctxconfig->source != GLFW_NATIVE_CONTEXT_API &&
62 ctxconfig->source != GLFW_EGL_CONTEXT_API &&
63 ctxconfig->source != GLFW_OSMESA_CONTEXT_API)
64 {
65 _glfwInputError(GLFW_INVALID_ENUM,
66 "Invalid context creation API 0x%08X",
67 ctxconfig->source);
68 return GLFW_FALSE;
69 }
70
71 if (ctxconfig->client != GLFW_NO_API &&
72 ctxconfig->client != GLFW_OPENGL_API &&
73 ctxconfig->client != GLFW_OPENGL_ES_API)
74 {
75 _glfwInputError(GLFW_INVALID_ENUM,
76 "Invalid client API 0x%08X",
77 ctxconfig->client);
78 return GLFW_FALSE;
79 }
80
81 if (ctxconfig->client == GLFW_OPENGL_API)
82 {
83 if ((ctxconfig->major < 1 || ctxconfig->minor < 0) ||
84 (ctxconfig->major == 1 && ctxconfig->minor > 5) ||
85 (ctxconfig->major == 2 && ctxconfig->minor > 1) ||
86 (ctxconfig->major == 3 && ctxconfig->minor > 3))
87 {
88 // OpenGL 1.0 is the smallest valid version
89 // OpenGL 1.x series ended with version 1.5
90 // OpenGL 2.x series ended with version 2.1
91 // OpenGL 3.x series ended with version 3.3
92 // For now, let everything else through
93
94 _glfwInputError(GLFW_INVALID_VALUE,
95 "Invalid OpenGL version %i.%i",
96 ctxconfig->major, ctxconfig->minor);
97 return GLFW_FALSE;
98 }
99
100 if (ctxconfig->profile)
101 {
102 if (ctxconfig->profile != GLFW_OPENGL_CORE_PROFILE &&
103 ctxconfig->profile != GLFW_OPENGL_COMPAT_PROFILE)
104 {
105 _glfwInputError(GLFW_INVALID_ENUM,
106 "Invalid OpenGL profile 0x%08X",
107 ctxconfig->profile);
108 return GLFW_FALSE;
109 }
110
111 if (ctxconfig->major <= 2 ||
112 (ctxconfig->major == 3 && ctxconfig->minor < 2))
113 {
114 // Desktop OpenGL context profiles are only defined for version 3.2
115 // and above
116
117 _glfwInputError(GLFW_INVALID_VALUE,
118 "Context profiles are only defined for OpenGL version 3.2 and above");
119 return GLFW_FALSE;
120 }
121 }
122
123 if (ctxconfig->forward && ctxconfig->major <= 2)
124 {
125 // Forward-compatible contexts are only defined for OpenGL version 3.0 and above
126 _glfwInputError(GLFW_INVALID_VALUE,
127 "Forward-compatibility is only defined for OpenGL version 3.0 and above");
128 return GLFW_FALSE;
129 }
130 }
131 else if (ctxconfig->client == GLFW_OPENGL_ES_API)
132 {
133 if (ctxconfig->major < 1 || ctxconfig->minor < 0 ||
134 (ctxconfig->major == 1 && ctxconfig->minor > 1) ||
135 (ctxconfig->major == 2 && ctxconfig->minor > 0))
136 {
137 // OpenGL ES 1.0 is the smallest valid version
138 // OpenGL ES 1.x series ended with version 1.1
139 // OpenGL ES 2.x series ended with version 2.0
140 // For now, let everything else through
141
142 _glfwInputError(GLFW_INVALID_VALUE,
143 "Invalid OpenGL ES version %i.%i",
144 ctxconfig->major, ctxconfig->minor);
145 return GLFW_FALSE;
146 }
147 }
148
149 if (ctxconfig->robustness)
150 {
151 if (ctxconfig->robustness != GLFW_NO_RESET_NOTIFICATION &&
152 ctxconfig->robustness != GLFW_LOSE_CONTEXT_ON_RESET)
153 {
154 _glfwInputError(GLFW_INVALID_ENUM,
155 "Invalid context robustness mode 0x%08X",
156 ctxconfig->robustness);
157 return GLFW_FALSE;
158 }
159 }
160
161 if (ctxconfig->release)
162 {
163 if (ctxconfig->release != GLFW_RELEASE_BEHAVIOR_NONE &&
164 ctxconfig->release != GLFW_RELEASE_BEHAVIOR_FLUSH)
165 {
166 _glfwInputError(GLFW_INVALID_ENUM,
167 "Invalid context release behavior 0x%08X",
168 ctxconfig->release);
169 return GLFW_FALSE;
170 }
171 }
172
173 return GLFW_TRUE;
174}
175
176// Chooses the framebuffer config that best matches the desired one
177//
178const _GLFWfbconfig* _glfwChooseFBConfig(const _GLFWfbconfig* desired,
179 const _GLFWfbconfig* alternatives,
180 unsigned int count)
181{
182 unsigned int i;
183 unsigned int missing, leastMissing = UINT_MAX;
184 unsigned int colorDiff, leastColorDiff = UINT_MAX;
185 unsigned int extraDiff, leastExtraDiff = UINT_MAX;
186 const _GLFWfbconfig* current;
187 const _GLFWfbconfig* closest = NULL;
188
189 for (i = 0; i < count; i++)
190 {
191 current = alternatives + i;
192
193 if (desired->stereo > 0 && current->stereo == 0)
194 {
195 // Stereo is a hard constraint
196 continue;
197 }
198
199 if (desired->doublebuffer != current->doublebuffer)
200 {
201 // Double buffering is a hard constraint
202 continue;
203 }
204
205 // Count number of missing buffers
206 {
207 missing = 0;
208
209 if (desired->alphaBits > 0 && current->alphaBits == 0)
210 missing++;
211
212 if (desired->depthBits > 0 && current->depthBits == 0)
213 missing++;
214
215 if (desired->stencilBits > 0 && current->stencilBits == 0)
216 missing++;
217
218 if (desired->auxBuffers > 0 &&
219 current->auxBuffers < desired->auxBuffers)
220 {
221 missing += desired->auxBuffers - current->auxBuffers;
222 }
223
224 if (desired->samples > 0 && current->samples == 0)
225 {
226 // Technically, several multisampling buffers could be
227 // involved, but that's a lower level implementation detail and
228 // not important to us here, so we count them as one
229 missing++;
230 }
231
232 if (desired->transparent != current->transparent)
233 missing++;
234 }
235
236 // These polynomials make many small channel size differences matter
237 // less than one large channel size difference
238
239 // Calculate color channel size difference value
240 {
241 colorDiff = 0;
242
243 if (desired->redBits != GLFW_DONT_CARE)
244 {
245 colorDiff += (desired->redBits - current->redBits) *
246 (desired->redBits - current->redBits);
247 }
248
249 if (desired->greenBits != GLFW_DONT_CARE)
250 {
251 colorDiff += (desired->greenBits - current->greenBits) *
252 (desired->greenBits - current->greenBits);
253 }
254
255 if (desired->blueBits != GLFW_DONT_CARE)
256 {
257 colorDiff += (desired->blueBits - current->blueBits) *
258 (desired->blueBits - current->blueBits);
259 }
260 }
261
262 // Calculate non-color channel size difference value
263 {
264 extraDiff = 0;
265
266 if (desired->alphaBits != GLFW_DONT_CARE)
267 {
268 extraDiff += (desired->alphaBits - current->alphaBits) *
269 (desired->alphaBits - current->alphaBits);
270 }
271
272 if (desired->depthBits != GLFW_DONT_CARE)
273 {
274 extraDiff += (desired->depthBits - current->depthBits) *
275 (desired->depthBits - current->depthBits);
276 }
277
278 if (desired->stencilBits != GLFW_DONT_CARE)
279 {
280 extraDiff += (desired->stencilBits - current->stencilBits) *
281 (desired->stencilBits - current->stencilBits);
282 }
283
284 if (desired->accumRedBits != GLFW_DONT_CARE)
285 {
286 extraDiff += (desired->accumRedBits - current->accumRedBits) *
287 (desired->accumRedBits - current->accumRedBits);
288 }
289
290 if (desired->accumGreenBits != GLFW_DONT_CARE)
291 {
292 extraDiff += (desired->accumGreenBits - current->accumGreenBits) *
293 (desired->accumGreenBits - current->accumGreenBits);
294 }
295
296 if (desired->accumBlueBits != GLFW_DONT_CARE)
297 {
298 extraDiff += (desired->accumBlueBits - current->accumBlueBits) *
299 (desired->accumBlueBits - current->accumBlueBits);
300 }
301
302 if (desired->accumAlphaBits != GLFW_DONT_CARE)
303 {
304 extraDiff += (desired->accumAlphaBits - current->accumAlphaBits) *
305 (desired->accumAlphaBits - current->accumAlphaBits);
306 }
307
308 if (desired->samples != GLFW_DONT_CARE)
309 {
310 extraDiff += (desired->samples - current->samples) *
311 (desired->samples - current->samples);
312 }
313
314 if (desired->sRGB && !current->sRGB)
315 extraDiff++;
316 }
317
318 // Figure out if the current one is better than the best one found so far
319 // Least number of missing buffers is the most important heuristic,
320 // then color buffer size match and lastly size match for other buffers
321
322 if (missing < leastMissing)
323 closest = current;
324 else if (missing == leastMissing)
325 {
326 if ((colorDiff < leastColorDiff) ||
327 (colorDiff == leastColorDiff && extraDiff < leastExtraDiff))
328 {
329 closest = current;
330 }
331 }
332
333 if (current == closest)
334 {
335 leastMissing = missing;
336 leastColorDiff = colorDiff;
337 leastExtraDiff = extraDiff;
338 }
339 }
340
341 return closest;
342}
343
344// Retrieves the attributes of the current context
345//
346GLFWbool _glfwRefreshContextAttribs(_GLFWwindow* window,
347 const _GLFWctxconfig* ctxconfig)
348{
349 int i;
350 _GLFWwindow* previous;
351 const char* version;
352 const char* prefixes[] =
353 {
354 "OpenGL ES-CM ",
355 "OpenGL ES-CL ",
356 "OpenGL ES ",
357 NULL
358 };
359
360 window->context.source = ctxconfig->source;
361 window->context.client = GLFW_OPENGL_API;
362
363 previous = _glfwPlatformGetTls(&_glfw.contextSlot);
364 glfwMakeContextCurrent((GLFWwindow*) window);
365
366 window->context.GetIntegerv = (PFNGLGETINTEGERVPROC)
367 window->context.getProcAddress("glGetIntegerv");
368 window->context.GetString = (PFNGLGETSTRINGPROC)
369 window->context.getProcAddress("glGetString");
370 if (!window->context.GetIntegerv || !window->context.GetString)
371 {
372 _glfwInputError(GLFW_PLATFORM_ERROR, "Entry point retrieval is broken");
373 glfwMakeContextCurrent((GLFWwindow*) previous);
374 return GLFW_FALSE;
375 }
376
377 version = (const char*) window->context.GetString(GL_VERSION);
378 if (!version)
379 {
380 if (ctxconfig->client == GLFW_OPENGL_API)
381 {
382 _glfwInputError(GLFW_PLATFORM_ERROR,
383 "OpenGL version string retrieval is broken");
384 }
385 else
386 {
387 _glfwInputError(GLFW_PLATFORM_ERROR,
388 "OpenGL ES version string retrieval is broken");
389 }
390
391 glfwMakeContextCurrent((GLFWwindow*) previous);
392 return GLFW_FALSE;
393 }
394
395 for (i = 0; prefixes[i]; i++)
396 {
397 const size_t length = strlen(prefixes[i]);
398
399 if (strncmp(version, prefixes[i], length) == 0)
400 {
401 version += length;
402 window->context.client = GLFW_OPENGL_ES_API;
403 break;
404 }
405 }
406
407 if (!sscanf(version, "%d.%d.%d",
408 &window->context.major,
409 &window->context.minor,
410 &window->context.revision))
411 {
412 if (window->context.client == GLFW_OPENGL_API)
413 {
414 _glfwInputError(GLFW_PLATFORM_ERROR,
415 "No version found in OpenGL version string");
416 }
417 else
418 {
419 _glfwInputError(GLFW_PLATFORM_ERROR,
420 "No version found in OpenGL ES version string");
421 }
422
423 glfwMakeContextCurrent((GLFWwindow*) previous);
424 return GLFW_FALSE;
425 }
426
427 if (window->context.major < ctxconfig->major ||
428 (window->context.major == ctxconfig->major &&
429 window->context.minor < ctxconfig->minor))
430 {
431 // The desired OpenGL version is greater than the actual version
432 // This only happens if the machine lacks {GLX|WGL}_ARB_create_context
433 // /and/ the user has requested an OpenGL version greater than 1.0
434
435 // For API consistency, we emulate the behavior of the
436 // {GLX|WGL}_ARB_create_context extension and fail here
437
438 if (window->context.client == GLFW_OPENGL_API)
439 {
440 _glfwInputError(GLFW_VERSION_UNAVAILABLE,
441 "Requested OpenGL version %i.%i, got version %i.%i",
442 ctxconfig->major, ctxconfig->minor,
443 window->context.major, window->context.minor);
444 }
445 else
446 {
447 _glfwInputError(GLFW_VERSION_UNAVAILABLE,
448 "Requested OpenGL ES version %i.%i, got version %i.%i",
449 ctxconfig->major, ctxconfig->minor,
450 window->context.major, window->context.minor);
451 }
452
453 glfwMakeContextCurrent((GLFWwindow*) previous);
454 return GLFW_FALSE;
455 }
456
457 if (window->context.major >= 3)
458 {
459 // OpenGL 3.0+ uses a different function for extension string retrieval
460 // We cache it here instead of in glfwExtensionSupported mostly to alert
461 // users as early as possible that their build may be broken
462
463 window->context.GetStringi = (PFNGLGETSTRINGIPROC)
464 window->context.getProcAddress("glGetStringi");
465 if (!window->context.GetStringi)
466 {
467 _glfwInputError(GLFW_PLATFORM_ERROR,
468 "Entry point retrieval is broken");
469 glfwMakeContextCurrent((GLFWwindow*) previous);
470 return GLFW_FALSE;
471 }
472 }
473
474 if (window->context.client == GLFW_OPENGL_API)
475 {
476 // Read back context flags (OpenGL 3.0 and above)
477 if (window->context.major >= 3)
478 {
479 GLint flags;
480 window->context.GetIntegerv(GL_CONTEXT_FLAGS, &flags);
481
482 if (flags & GL_CONTEXT_FLAG_FORWARD_COMPATIBLE_BIT)
483 window->context.forward = GLFW_TRUE;
484
485 if (flags & GL_CONTEXT_FLAG_DEBUG_BIT)
486 window->context.debug = GLFW_TRUE;
487 else if (glfwExtensionSupported("GL_ARB_debug_output") &&
488 ctxconfig->debug)
489 {
490 // HACK: This is a workaround for older drivers (pre KHR_debug)
491 // not setting the debug bit in the context flags for
492 // debug contexts
493 window->context.debug = GLFW_TRUE;
494 }
495
496 if (flags & GL_CONTEXT_FLAG_NO_ERROR_BIT_KHR)
497 window->context.noerror = GLFW_TRUE;
498 }
499
500 // Read back OpenGL context profile (OpenGL 3.2 and above)
501 if (window->context.major >= 4 ||
502 (window->context.major == 3 && window->context.minor >= 2))
503 {
504 GLint mask;
505 window->context.GetIntegerv(GL_CONTEXT_PROFILE_MASK, &mask);
506
507 if (mask & GL_CONTEXT_COMPATIBILITY_PROFILE_BIT)
508 window->context.profile = GLFW_OPENGL_COMPAT_PROFILE;
509 else if (mask & GL_CONTEXT_CORE_PROFILE_BIT)
510 window->context.profile = GLFW_OPENGL_CORE_PROFILE;
511 else if (glfwExtensionSupported("GL_ARB_compatibility"))
512 {
513 // HACK: This is a workaround for the compatibility profile bit
514 // not being set in the context flags if an OpenGL 3.2+
515 // context was created without having requested a specific
516 // version
517 window->context.profile = GLFW_OPENGL_COMPAT_PROFILE;
518 }
519 }
520
521 // Read back robustness strategy
522 if (glfwExtensionSupported("GL_ARB_robustness"))
523 {
524 // NOTE: We avoid using the context flags for detection, as they are
525 // only present from 3.0 while the extension applies from 1.1
526
527 GLint strategy;
528 window->context.GetIntegerv(GL_RESET_NOTIFICATION_STRATEGY_ARB,
529 &strategy);
530
531 if (strategy == GL_LOSE_CONTEXT_ON_RESET_ARB)
532 window->context.robustness = GLFW_LOSE_CONTEXT_ON_RESET;
533 else if (strategy == GL_NO_RESET_NOTIFICATION_ARB)
534 window->context.robustness = GLFW_NO_RESET_NOTIFICATION;
535 }
536 }
537 else
538 {
539 // Read back robustness strategy
540 if (glfwExtensionSupported("GL_EXT_robustness"))
541 {
542 // NOTE: The values of these constants match those of the OpenGL ARB
543 // one, so we can reuse them here
544
545 GLint strategy;
546 window->context.GetIntegerv(GL_RESET_NOTIFICATION_STRATEGY_ARB,
547 &strategy);
548
549 if (strategy == GL_LOSE_CONTEXT_ON_RESET_ARB)
550 window->context.robustness = GLFW_LOSE_CONTEXT_ON_RESET;
551 else if (strategy == GL_NO_RESET_NOTIFICATION_ARB)
552 window->context.robustness = GLFW_NO_RESET_NOTIFICATION;
553 }
554 }
555
556 if (glfwExtensionSupported("GL_KHR_context_flush_control"))
557 {
558 GLint behavior;
559 window->context.GetIntegerv(GL_CONTEXT_RELEASE_BEHAVIOR, &behavior);
560
561 if (behavior == GL_NONE)
562 window->context.release = GLFW_RELEASE_BEHAVIOR_NONE;
563 else if (behavior == GL_CONTEXT_RELEASE_BEHAVIOR_FLUSH)
564 window->context.release = GLFW_RELEASE_BEHAVIOR_FLUSH;
565 }
566
567 // Clearing the front buffer to black to avoid garbage pixels left over from
568 // previous uses of our bit of VRAM
569 {
570 PFNGLCLEARPROC glClear = (PFNGLCLEARPROC)
571 window->context.getProcAddress("glClear");
572 glClear(GL_COLOR_BUFFER_BIT);
573 window->context.swapBuffers(window);
574 }
575
576 glfwMakeContextCurrent((GLFWwindow*) previous);
577 return GLFW_TRUE;
578}
579
580// Searches an extension string for the specified extension
581//
582GLFWbool _glfwStringInExtensionString(const char* string, const char* extensions)
583{
584 const char* start = extensions;
585
586 for (;;)
587 {
588 const char* where;
589 const char* terminator;
590
591 where = strstr(start, string);
592 if (!where)
593 return GLFW_FALSE;
594
595 terminator = where + strlen(string);
596 if (where == start || *(where - 1) == ' ')
597 {
598 if (*terminator == ' ' || *terminator == '\0')
599 break;
600 }
601
602 start = terminator;
603 }
604
605 return GLFW_TRUE;
606}
607
608
609//////////////////////////////////////////////////////////////////////////
610////// GLFW public API //////
611//////////////////////////////////////////////////////////////////////////
612
613GLFWAPI void glfwMakeContextCurrent(GLFWwindow* handle)
614{
615 _GLFWwindow* window = (_GLFWwindow*) handle;
616 _GLFWwindow* previous = _glfwPlatformGetTls(&_glfw.contextSlot);
617
618 _GLFW_REQUIRE_INIT();
619
620 if (window && window->context.client == GLFW_NO_API)
621 {
622 _glfwInputError(GLFW_NO_WINDOW_CONTEXT,
623 "Cannot make current with a window that has no OpenGL or OpenGL ES context");
624 return;
625 }
626
627 if (previous)
628 {
629 if (!window || window->context.source != previous->context.source)
630 previous->context.makeCurrent(NULL);
631 }
632
633 if (window)
634 window->context.makeCurrent(window);
635}
636
637GLFWAPI GLFWwindow* glfwGetCurrentContext(void)
638{
639 _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
640 return _glfwPlatformGetTls(&_glfw.contextSlot);
641}
642
643GLFWAPI void glfwSwapBuffers(GLFWwindow* handle)
644{
645 _GLFWwindow* window = (_GLFWwindow*) handle;
646 assert(window != NULL);
647
648 _GLFW_REQUIRE_INIT();
649
650 if (window->context.client == GLFW_NO_API)
651 {
652 _glfwInputError(GLFW_NO_WINDOW_CONTEXT,
653 "Cannot swap buffers of a window that has no OpenGL or OpenGL ES context");
654 return;
655 }
656
657 window->context.swapBuffers(window);
658}
659
660GLFWAPI void glfwSwapInterval(int interval)
661{
662 _GLFWwindow* window;
663
664 _GLFW_REQUIRE_INIT();
665
666 window = _glfwPlatformGetTls(&_glfw.contextSlot);
667 if (!window)
668 {
669 _glfwInputError(GLFW_NO_CURRENT_CONTEXT,
670 "Cannot set swap interval without a current OpenGL or OpenGL ES context");
671 return;
672 }
673
674 window->context.swapInterval(interval);
675}
676
677GLFWAPI int glfwExtensionSupported(const char* extension)
678{
679 _GLFWwindow* window;
680 assert(extension != NULL);
681
682 _GLFW_REQUIRE_INIT_OR_RETURN(GLFW_FALSE);
683
684 window = _glfwPlatformGetTls(&_glfw.contextSlot);
685 if (!window)
686 {
687 _glfwInputError(GLFW_NO_CURRENT_CONTEXT,
688 "Cannot query extension without a current OpenGL or OpenGL ES context");
689 return GLFW_FALSE;
690 }
691
692 if (*extension == '\0')
693 {
694 _glfwInputError(GLFW_INVALID_VALUE, "Extension name cannot be an empty string");
695 return GLFW_FALSE;
696 }
697
698 if (window->context.major >= 3)
699 {
700 int i;
701 GLint count;
702
703 // Check if extension is in the modern OpenGL extensions string list
704
705 window->context.GetIntegerv(GL_NUM_EXTENSIONS, &count);
706
707 for (i = 0; i < count; i++)
708 {
709 const char* en = (const char*)
710 window->context.GetStringi(GL_EXTENSIONS, i);
711 if (!en)
712 {
713 _glfwInputError(GLFW_PLATFORM_ERROR,
714 "Extension string retrieval is broken");
715 return GLFW_FALSE;
716 }
717
718 if (strcmp(en, extension) == 0)
719 return GLFW_TRUE;
720 }
721 }
722 else
723 {
724 // Check if extension is in the old style OpenGL extensions string
725
726 const char* extensions = (const char*)
727 window->context.GetString(GL_EXTENSIONS);
728 if (!extensions)
729 {
730 _glfwInputError(GLFW_PLATFORM_ERROR,
731 "Extension string retrieval is broken");
732 return GLFW_FALSE;
733 }
734
735 if (_glfwStringInExtensionString(extension, extensions))
736 return GLFW_TRUE;
737 }
738
739 // Check if extension is in the platform-specific string
740 return window->context.extensionSupported(extension);
741}
742
743GLFWAPI GLFWglproc glfwGetProcAddress(const char* procname)
744{
745 _GLFWwindow* window;
746 assert(procname != NULL);
747
748 _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
749
750 window = _glfwPlatformGetTls(&_glfw.contextSlot);
751 if (!window)
752 {
753 _glfwInputError(GLFW_NO_CURRENT_CONTEXT,
754 "Cannot query entry point without a current OpenGL or OpenGL ES context");
755 return NULL;
756 }
757
758 return window->context.getProcAddress(procname);
759}
760