1 //========================================================================
2 // GLFW 3.3 WGL - 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 
28 #include "internal.h"
29 
30 #include <stdlib.h>
31 #include <malloc.h>
32 #include <assert.h>
33 
34 
35 // Returns the specified attribute of the specified pixel format
36 //
getPixelFormatAttrib(_GLFWwindow * window,int pixelFormat,int attrib)37 static int getPixelFormatAttrib(_GLFWwindow* window, int pixelFormat, int attrib)
38 {
39     int value = 0;
40 
41     assert(_glfw.wgl.ARB_pixel_format);
42 
43     if (!_glfw.wgl.GetPixelFormatAttribivARB(window->context.wgl.dc,
44                                              pixelFormat,
45                                              0, 1, &attrib, &value))
46     {
47         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
48                              "WGL: Failed to retrieve pixel format attribute");
49         return 0;
50     }
51 
52     return value;
53 }
54 
55 // Return a list of available and usable framebuffer configs
56 //
choosePixelFormat(_GLFWwindow * window,const _GLFWctxconfig * ctxconfig,const _GLFWfbconfig * fbconfig)57 static int choosePixelFormat(_GLFWwindow* window,
58                              const _GLFWctxconfig* ctxconfig,
59                              const _GLFWfbconfig* fbconfig)
60 {
61     _GLFWfbconfig* usableConfigs;
62     const _GLFWfbconfig* closest;
63     int i, pixelFormat, nativeCount, usableCount;
64 
65     if (_glfw.wgl.ARB_pixel_format)
66     {
67         nativeCount = getPixelFormatAttrib(window,
68                                            1,
69                                            WGL_NUMBER_PIXEL_FORMATS_ARB);
70     }
71     else
72     {
73         nativeCount = DescribePixelFormat(window->context.wgl.dc,
74                                           1,
75                                           sizeof(PIXELFORMATDESCRIPTOR),
76                                           NULL);
77     }
78 
79     usableConfigs = calloc(nativeCount, sizeof(_GLFWfbconfig));
80     usableCount = 0;
81 
82     for (i = 0;  i < nativeCount;  i++)
83     {
84         const int n = i + 1;
85         _GLFWfbconfig* u = usableConfigs + usableCount;
86 
87         if (_glfw.wgl.ARB_pixel_format)
88         {
89             // Get pixel format attributes through "modern" extension
90 
91             if (!getPixelFormatAttrib(window, n, WGL_SUPPORT_OPENGL_ARB) ||
92                 !getPixelFormatAttrib(window, n, WGL_DRAW_TO_WINDOW_ARB))
93             {
94                 continue;
95             }
96 
97             if (getPixelFormatAttrib(window, n, WGL_PIXEL_TYPE_ARB) !=
98                 WGL_TYPE_RGBA_ARB)
99             {
100                 continue;
101             }
102 
103             if (getPixelFormatAttrib(window, n, WGL_ACCELERATION_ARB) ==
104                  WGL_NO_ACCELERATION_ARB)
105             {
106                 continue;
107             }
108 
109             u->redBits = getPixelFormatAttrib(window, n, WGL_RED_BITS_ARB);
110             u->greenBits = getPixelFormatAttrib(window, n, WGL_GREEN_BITS_ARB);
111             u->blueBits = getPixelFormatAttrib(window, n, WGL_BLUE_BITS_ARB);
112             u->alphaBits = getPixelFormatAttrib(window, n, WGL_ALPHA_BITS_ARB);
113 
114             u->depthBits = getPixelFormatAttrib(window, n, WGL_DEPTH_BITS_ARB);
115             u->stencilBits = getPixelFormatAttrib(window, n, WGL_STENCIL_BITS_ARB);
116 
117             u->accumRedBits = getPixelFormatAttrib(window, n, WGL_ACCUM_RED_BITS_ARB);
118             u->accumGreenBits = getPixelFormatAttrib(window, n, WGL_ACCUM_GREEN_BITS_ARB);
119             u->accumBlueBits = getPixelFormatAttrib(window, n, WGL_ACCUM_BLUE_BITS_ARB);
120             u->accumAlphaBits = getPixelFormatAttrib(window, n, WGL_ACCUM_ALPHA_BITS_ARB);
121 
122             u->auxBuffers = getPixelFormatAttrib(window, n, WGL_AUX_BUFFERS_ARB);
123 
124             if (getPixelFormatAttrib(window, n, WGL_STEREO_ARB))
125                 u->stereo = GLFW_TRUE;
126             if (getPixelFormatAttrib(window, n, WGL_DOUBLE_BUFFER_ARB))
127                 u->doublebuffer = GLFW_TRUE;
128 
129             if (_glfw.wgl.ARB_multisample)
130                 u->samples = getPixelFormatAttrib(window, n, WGL_SAMPLES_ARB);
131 
132             if (ctxconfig->client == GLFW_OPENGL_API)
133             {
134                 if (_glfw.wgl.ARB_framebuffer_sRGB ||
135                     _glfw.wgl.EXT_framebuffer_sRGB)
136                 {
137                     if (getPixelFormatAttrib(window, n, WGL_FRAMEBUFFER_SRGB_CAPABLE_ARB))
138                         u->sRGB = GLFW_TRUE;
139                 }
140             }
141             else
142             {
143                 if (_glfw.wgl.EXT_colorspace)
144                 {
145                     if (getPixelFormatAttrib(window, n, WGL_COLORSPACE_EXT) ==
146                         WGL_COLORSPACE_SRGB_EXT)
147                     {
148                         u->sRGB = GLFW_TRUE;
149                     }
150                 }
151             }
152         }
153         else
154         {
155             // Get pixel format attributes through legacy PFDs
156 
157             PIXELFORMATDESCRIPTOR pfd;
158 
159             if (!DescribePixelFormat(window->context.wgl.dc,
160                                      n,
161                                      sizeof(PIXELFORMATDESCRIPTOR),
162                                      &pfd))
163             {
164                 continue;
165             }
166 
167             if (!(pfd.dwFlags & PFD_DRAW_TO_WINDOW) ||
168                 !(pfd.dwFlags & PFD_SUPPORT_OPENGL))
169             {
170                 continue;
171             }
172 
173             if (!(pfd.dwFlags & PFD_GENERIC_ACCELERATED) &&
174                 (pfd.dwFlags & PFD_GENERIC_FORMAT))
175             {
176                 continue;
177             }
178 
179             if (pfd.iPixelType != PFD_TYPE_RGBA)
180                 continue;
181 
182             u->redBits = pfd.cRedBits;
183             u->greenBits = pfd.cGreenBits;
184             u->blueBits = pfd.cBlueBits;
185             u->alphaBits = pfd.cAlphaBits;
186 
187             u->depthBits = pfd.cDepthBits;
188             u->stencilBits = pfd.cStencilBits;
189 
190             u->accumRedBits = pfd.cAccumRedBits;
191             u->accumGreenBits = pfd.cAccumGreenBits;
192             u->accumBlueBits = pfd.cAccumBlueBits;
193             u->accumAlphaBits = pfd.cAccumAlphaBits;
194 
195             u->auxBuffers = pfd.cAuxBuffers;
196 
197             if (pfd.dwFlags & PFD_STEREO)
198                 u->stereo = GLFW_TRUE;
199             if (pfd.dwFlags & PFD_DOUBLEBUFFER)
200                 u->doublebuffer = GLFW_TRUE;
201         }
202 
203         u->handle = n;
204         usableCount++;
205     }
206 
207     if (!usableCount)
208     {
209         _glfwInputError(GLFW_API_UNAVAILABLE,
210                         "WGL: The driver does not appear to support OpenGL");
211 
212         free(usableConfigs);
213         return 0;
214     }
215 
216     closest = _glfwChooseFBConfig(fbconfig, usableConfigs, usableCount);
217     if (!closest)
218     {
219         _glfwInputError(GLFW_FORMAT_UNAVAILABLE,
220                         "WGL: Failed to find a suitable pixel format");
221 
222         free(usableConfigs);
223         return 0;
224     }
225 
226     pixelFormat = (int) closest->handle;
227     free(usableConfigs);
228 
229     return pixelFormat;
230 }
231 
makeContextCurrentWGL(_GLFWwindow * window)232 static void makeContextCurrentWGL(_GLFWwindow* window)
233 {
234     if (window)
235     {
236         if (wglMakeCurrent(window->context.wgl.dc, window->context.wgl.handle))
237             _glfwPlatformSetTls(&_glfw.contextSlot, window);
238         else
239         {
240             _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
241                                  "WGL: Failed to make context current");
242             _glfwPlatformSetTls(&_glfw.contextSlot, NULL);
243         }
244     }
245     else
246     {
247         if (!wglMakeCurrent(NULL, NULL))
248         {
249             _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
250                                  "WGL: Failed to clear current context");
251         }
252 
253         _glfwPlatformSetTls(&_glfw.contextSlot, NULL);
254     }
255 }
256 
swapBuffersWGL(_GLFWwindow * window)257 static void swapBuffersWGL(_GLFWwindow* window)
258 {
259     if (!window->monitor)
260     {
261         if (IsWindowsVistaOrGreater())
262         {
263             BOOL enabled;
264 
265             // HACK: Use DwmFlush when desktop composition is enabled
266             if (SUCCEEDED(DwmIsCompositionEnabled(&enabled)) && enabled)
267             {
268                 int count = abs(window->context.wgl.interval);
269                 while (count--)
270                     DwmFlush();
271             }
272         }
273     }
274 
275     SwapBuffers(window->context.wgl.dc);
276 }
277 
swapIntervalWGL(int interval)278 static void swapIntervalWGL(int interval)
279 {
280     _GLFWwindow* window = _glfwPlatformGetTls(&_glfw.contextSlot);
281 
282     window->context.wgl.interval = interval;
283 
284     if (!window->monitor)
285     {
286         if (IsWindowsVistaOrGreater())
287         {
288             BOOL enabled;
289 
290             // HACK: Disable WGL swap interval when desktop composition is enabled to
291             //       avoid interfering with DWM vsync
292             if (SUCCEEDED(DwmIsCompositionEnabled(&enabled)) && enabled)
293                 interval = 0;
294         }
295     }
296 
297     if (_glfw.wgl.EXT_swap_control)
298         _glfw.wgl.SwapIntervalEXT(interval);
299 }
300 
extensionSupportedWGL(const char * extension)301 static int extensionSupportedWGL(const char* extension)
302 {
303     const char* extensions = NULL;
304 
305     if (_glfw.wgl.GetExtensionsStringARB)
306         extensions = _glfw.wgl.GetExtensionsStringARB(wglGetCurrentDC());
307     else if (_glfw.wgl.GetExtensionsStringEXT)
308         extensions = _glfw.wgl.GetExtensionsStringEXT();
309 
310     if (!extensions)
311         return GLFW_FALSE;
312 
313     return _glfwStringInExtensionString(extension, extensions);
314 }
315 
getProcAddressWGL(const char * procname)316 static GLFWglproc getProcAddressWGL(const char* procname)
317 {
318     const GLFWglproc proc = (GLFWglproc) wglGetProcAddress(procname);
319     if (proc)
320         return proc;
321 
322     return (GLFWglproc) GetProcAddress(_glfw.wgl.instance, procname);
323 }
324 
325 // Destroy the OpenGL context
326 //
destroyContextWGL(_GLFWwindow * window)327 static void destroyContextWGL(_GLFWwindow* window)
328 {
329     if (window->context.wgl.handle)
330     {
331         wglDeleteContext(window->context.wgl.handle);
332         window->context.wgl.handle = NULL;
333     }
334 }
335 
336 
337 //////////////////////////////////////////////////////////////////////////
338 //////                       GLFW internal API                      //////
339 //////////////////////////////////////////////////////////////////////////
340 
341 // Initialize WGL
342 //
_glfwInitWGL(void)343 GLFWbool _glfwInitWGL(void)
344 {
345     PIXELFORMATDESCRIPTOR pfd;
346     HGLRC prc, rc;
347     HDC pdc, dc;
348 
349     if (_glfw.wgl.instance)
350         return GLFW_TRUE;
351 
352     _glfw.wgl.instance = LoadLibraryA("opengl32.dll");
353     if (!_glfw.wgl.instance)
354     {
355         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
356                              "WGL: Failed to load opengl32.dll");
357         return GLFW_FALSE;
358     }
359 
360     _glfw.wgl.CreateContext = (PFN_wglCreateContext)
361         GetProcAddress(_glfw.wgl.instance, "wglCreateContext");
362     _glfw.wgl.DeleteContext = (PFN_wglDeleteContext)
363         GetProcAddress(_glfw.wgl.instance, "wglDeleteContext");
364     _glfw.wgl.GetProcAddress = (PFN_wglGetProcAddress)
365         GetProcAddress(_glfw.wgl.instance, "wglGetProcAddress");
366     _glfw.wgl.GetCurrentDC = (PFN_wglGetCurrentDC)
367         GetProcAddress(_glfw.wgl.instance, "wglGetCurrentDC");
368     _glfw.wgl.GetCurrentContext = (PFN_wglGetCurrentContext)
369         GetProcAddress(_glfw.wgl.instance, "wglGetCurrentContext");
370     _glfw.wgl.MakeCurrent = (PFN_wglMakeCurrent)
371         GetProcAddress(_glfw.wgl.instance, "wglMakeCurrent");
372     _glfw.wgl.ShareLists = (PFN_wglShareLists)
373         GetProcAddress(_glfw.wgl.instance, "wglShareLists");
374 
375     // NOTE: A dummy context has to be created for opengl32.dll to load the
376     //       OpenGL ICD, from which we can then query WGL extensions
377     // NOTE: This code will accept the Microsoft GDI ICD; accelerated context
378     //       creation failure occurs during manual pixel format enumeration
379 
380     dc = GetDC(_glfw.win32.helperWindowHandle);;
381 
382     ZeroMemory(&pfd, sizeof(pfd));
383     pfd.nSize = sizeof(pfd);
384     pfd.nVersion = 1;
385     pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
386     pfd.iPixelType = PFD_TYPE_RGBA;
387     pfd.cColorBits = 24;
388 
389     if (!SetPixelFormat(dc, ChoosePixelFormat(dc, &pfd), &pfd))
390     {
391         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
392                              "WGL: Failed to set pixel format for dummy context");
393         return GLFW_FALSE;
394     }
395 
396     rc = wglCreateContext(dc);
397     if (!rc)
398     {
399         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
400                              "WGL: Failed to create dummy context");
401         return GLFW_FALSE;
402     }
403 
404     pdc = wglGetCurrentDC();
405     prc = wglGetCurrentContext();
406 
407     if (!wglMakeCurrent(dc, rc))
408     {
409         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
410                              "WGL: Failed to make dummy context current");
411         wglMakeCurrent(pdc, prc);
412         wglDeleteContext(rc);
413         return GLFW_FALSE;
414     }
415 
416     // NOTE: Functions must be loaded first as they're needed to retrieve the
417     //       extension string that tells us whether the functions are supported
418     _glfw.wgl.GetExtensionsStringEXT = (PFNWGLGETEXTENSIONSSTRINGEXTPROC)
419         wglGetProcAddress("wglGetExtensionsStringEXT");
420     _glfw.wgl.GetExtensionsStringARB = (PFNWGLGETEXTENSIONSSTRINGARBPROC)
421         wglGetProcAddress("wglGetExtensionsStringARB");
422     _glfw.wgl.CreateContextAttribsARB = (PFNWGLCREATECONTEXTATTRIBSARBPROC)
423         wglGetProcAddress("wglCreateContextAttribsARB");
424     _glfw.wgl.SwapIntervalEXT = (PFNWGLSWAPINTERVALEXTPROC)
425         wglGetProcAddress("wglSwapIntervalEXT");
426     _glfw.wgl.GetPixelFormatAttribivARB = (PFNWGLGETPIXELFORMATATTRIBIVARBPROC)
427         wglGetProcAddress("wglGetPixelFormatAttribivARB");
428 
429     // NOTE: WGL_ARB_extensions_string and WGL_EXT_extensions_string are not
430     //       checked below as we are already using them
431     _glfw.wgl.ARB_multisample =
432         extensionSupportedWGL("WGL_ARB_multisample");
433     _glfw.wgl.ARB_framebuffer_sRGB =
434         extensionSupportedWGL("WGL_ARB_framebuffer_sRGB");
435     _glfw.wgl.EXT_framebuffer_sRGB =
436         extensionSupportedWGL("WGL_EXT_framebuffer_sRGB");
437     _glfw.wgl.ARB_create_context =
438         extensionSupportedWGL("WGL_ARB_create_context");
439     _glfw.wgl.ARB_create_context_profile =
440         extensionSupportedWGL("WGL_ARB_create_context_profile");
441     _glfw.wgl.EXT_create_context_es2_profile =
442         extensionSupportedWGL("WGL_EXT_create_context_es2_profile");
443     _glfw.wgl.ARB_create_context_robustness =
444         extensionSupportedWGL("WGL_ARB_create_context_robustness");
445     _glfw.wgl.ARB_create_context_no_error =
446         extensionSupportedWGL("WGL_ARB_create_context_no_error");
447     _glfw.wgl.EXT_swap_control =
448         extensionSupportedWGL("WGL_EXT_swap_control");
449     _glfw.wgl.EXT_colorspace =
450         extensionSupportedWGL("WGL_EXT_colorspace");
451     _glfw.wgl.ARB_pixel_format =
452         extensionSupportedWGL("WGL_ARB_pixel_format");
453     _glfw.wgl.ARB_context_flush_control =
454         extensionSupportedWGL("WGL_ARB_context_flush_control");
455 
456     wglMakeCurrent(pdc, prc);
457     wglDeleteContext(rc);
458     return GLFW_TRUE;
459 }
460 
461 // Terminate WGL
462 //
_glfwTerminateWGL(void)463 void _glfwTerminateWGL(void)
464 {
465     if (_glfw.wgl.instance)
466         FreeLibrary(_glfw.wgl.instance);
467 }
468 
469 #define setAttrib(a, v) \
470 { \
471     assert((size_t) (index + 1) < sizeof(attribs) / sizeof(attribs[0])); \
472     attribs[index++] = a; \
473     attribs[index++] = v; \
474 }
475 
476 // Create the OpenGL or OpenGL ES context
477 //
_glfwCreateContextWGL(_GLFWwindow * window,const _GLFWctxconfig * ctxconfig,const _GLFWfbconfig * fbconfig)478 GLFWbool _glfwCreateContextWGL(_GLFWwindow* window,
479                                const _GLFWctxconfig* ctxconfig,
480                                const _GLFWfbconfig* fbconfig)
481 {
482     int attribs[40];
483     int pixelFormat;
484     PIXELFORMATDESCRIPTOR pfd;
485     HGLRC share = NULL;
486 
487     if (ctxconfig->share)
488         share = ctxconfig->share->context.wgl.handle;
489 
490     window->context.wgl.dc = GetDC(window->win32.handle);
491     if (!window->context.wgl.dc)
492     {
493         _glfwInputError(GLFW_PLATFORM_ERROR,
494                         "WGL: Failed to retrieve DC for window");
495         return GLFW_FALSE;
496     }
497 
498     pixelFormat = choosePixelFormat(window, ctxconfig, fbconfig);
499     if (!pixelFormat)
500         return GLFW_FALSE;
501 
502     if (!DescribePixelFormat(window->context.wgl.dc,
503                              pixelFormat, sizeof(pfd), &pfd))
504     {
505         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
506                              "WGL: Failed to retrieve PFD for selected pixel format");
507         return GLFW_FALSE;
508     }
509 
510     if (!SetPixelFormat(window->context.wgl.dc, pixelFormat, &pfd))
511     {
512         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
513                              "WGL: Failed to set selected pixel format");
514         return GLFW_FALSE;
515     }
516 
517     if (ctxconfig->client == GLFW_OPENGL_API)
518     {
519         if (ctxconfig->forward)
520         {
521             if (!_glfw.wgl.ARB_create_context)
522             {
523                 _glfwInputError(GLFW_VERSION_UNAVAILABLE,
524                                 "WGL: A forward compatible OpenGL context requested but WGL_ARB_create_context is unavailable");
525                 return GLFW_FALSE;
526             }
527         }
528 
529         if (ctxconfig->profile)
530         {
531             if (!_glfw.wgl.ARB_create_context_profile)
532             {
533                 _glfwInputError(GLFW_VERSION_UNAVAILABLE,
534                                 "WGL: OpenGL profile requested but WGL_ARB_create_context_profile is unavailable");
535                 return GLFW_FALSE;
536             }
537         }
538     }
539     else
540     {
541         if (!_glfw.wgl.ARB_create_context ||
542             !_glfw.wgl.ARB_create_context_profile ||
543             !_glfw.wgl.EXT_create_context_es2_profile)
544         {
545             _glfwInputError(GLFW_API_UNAVAILABLE,
546                             "WGL: OpenGL ES requested but WGL_ARB_create_context_es2_profile is unavailable");
547             return GLFW_FALSE;
548         }
549     }
550 
551     if (_glfw.wgl.ARB_create_context)
552     {
553         int index = 0, mask = 0, flags = 0;
554 
555         if (ctxconfig->client == GLFW_OPENGL_API)
556         {
557             if (ctxconfig->forward)
558                 flags |= WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
559 
560             if (ctxconfig->profile == GLFW_OPENGL_CORE_PROFILE)
561                 mask |= WGL_CONTEXT_CORE_PROFILE_BIT_ARB;
562             else if (ctxconfig->profile == GLFW_OPENGL_COMPAT_PROFILE)
563                 mask |= WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB;
564         }
565         else
566             mask |= WGL_CONTEXT_ES2_PROFILE_BIT_EXT;
567 
568         if (ctxconfig->debug)
569             flags |= WGL_CONTEXT_DEBUG_BIT_ARB;
570 
571         if (ctxconfig->robustness)
572         {
573             if (_glfw.wgl.ARB_create_context_robustness)
574             {
575                 if (ctxconfig->robustness == GLFW_NO_RESET_NOTIFICATION)
576                 {
577                     setAttrib(WGL_CONTEXT_RESET_NOTIFICATION_STRATEGY_ARB,
578                               WGL_NO_RESET_NOTIFICATION_ARB);
579                 }
580                 else if (ctxconfig->robustness == GLFW_LOSE_CONTEXT_ON_RESET)
581                 {
582                     setAttrib(WGL_CONTEXT_RESET_NOTIFICATION_STRATEGY_ARB,
583                               WGL_LOSE_CONTEXT_ON_RESET_ARB);
584                 }
585 
586                 flags |= WGL_CONTEXT_ROBUST_ACCESS_BIT_ARB;
587             }
588         }
589 
590         if (ctxconfig->release)
591         {
592             if (_glfw.wgl.ARB_context_flush_control)
593             {
594                 if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_NONE)
595                 {
596                     setAttrib(WGL_CONTEXT_RELEASE_BEHAVIOR_ARB,
597                               WGL_CONTEXT_RELEASE_BEHAVIOR_NONE_ARB);
598                 }
599                 else if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_FLUSH)
600                 {
601                     setAttrib(WGL_CONTEXT_RELEASE_BEHAVIOR_ARB,
602                               WGL_CONTEXT_RELEASE_BEHAVIOR_FLUSH_ARB);
603                 }
604             }
605         }
606 
607         if (ctxconfig->noerror)
608         {
609             if (_glfw.wgl.ARB_create_context_no_error)
610                 setAttrib(WGL_CONTEXT_OPENGL_NO_ERROR_ARB, GLFW_TRUE);
611         }
612 
613         // NOTE: Only request an explicitly versioned context when necessary, as
614         //       explicitly requesting version 1.0 does not always return the
615         //       highest version supported by the driver
616         if (ctxconfig->major != 1 || ctxconfig->minor != 0)
617         {
618             setAttrib(WGL_CONTEXT_MAJOR_VERSION_ARB, ctxconfig->major);
619             setAttrib(WGL_CONTEXT_MINOR_VERSION_ARB, ctxconfig->minor);
620         }
621 
622         if (flags)
623             setAttrib(WGL_CONTEXT_FLAGS_ARB, flags);
624 
625         if (mask)
626             setAttrib(WGL_CONTEXT_PROFILE_MASK_ARB, mask);
627 
628         setAttrib(0, 0);
629 
630         window->context.wgl.handle =
631             _glfw.wgl.CreateContextAttribsARB(window->context.wgl.dc,
632                                               share, attribs);
633         if (!window->context.wgl.handle)
634         {
635             const DWORD error = GetLastError();
636 
637             if (error == (0xc0070000 | ERROR_INVALID_VERSION_ARB))
638             {
639                 if (ctxconfig->client == GLFW_OPENGL_API)
640                 {
641                     _glfwInputError(GLFW_VERSION_UNAVAILABLE,
642                                     "WGL: Driver does not support OpenGL version %i.%i",
643                                     ctxconfig->major,
644                                     ctxconfig->minor);
645                 }
646                 else
647                 {
648                     _glfwInputError(GLFW_VERSION_UNAVAILABLE,
649                                     "WGL: Driver does not support OpenGL ES version %i.%i",
650                                     ctxconfig->major,
651                                     ctxconfig->minor);
652                 }
653             }
654             else if (error == (0xc0070000 | ERROR_INVALID_PROFILE_ARB))
655             {
656                 _glfwInputError(GLFW_VERSION_UNAVAILABLE,
657                                 "WGL: Driver does not support the requested OpenGL profile");
658             }
659             else if (error == (0xc0070000 | ERROR_INCOMPATIBLE_DEVICE_CONTEXTS_ARB))
660             {
661                 _glfwInputError(GLFW_INVALID_VALUE,
662                                 "WGL: The share context is not compatible with the requested context");
663             }
664             else
665             {
666                 if (ctxconfig->client == GLFW_OPENGL_API)
667                 {
668                     _glfwInputError(GLFW_VERSION_UNAVAILABLE,
669                                     "WGL: Failed to create OpenGL context");
670                 }
671                 else
672                 {
673                     _glfwInputError(GLFW_VERSION_UNAVAILABLE,
674                                     "WGL: Failed to create OpenGL ES context");
675                 }
676             }
677 
678             return GLFW_FALSE;
679         }
680     }
681     else
682     {
683         window->context.wgl.handle = wglCreateContext(window->context.wgl.dc);
684         if (!window->context.wgl.handle)
685         {
686             _glfwInputErrorWin32(GLFW_VERSION_UNAVAILABLE,
687                                  "WGL: Failed to create OpenGL context");
688             return GLFW_FALSE;
689         }
690 
691         if (share)
692         {
693             if (!wglShareLists(share, window->context.wgl.handle))
694             {
695                 _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
696                                      "WGL: Failed to enable sharing with specified OpenGL context");
697                 return GLFW_FALSE;
698             }
699         }
700     }
701 
702     window->context.makeCurrent = makeContextCurrentWGL;
703     window->context.swapBuffers = swapBuffersWGL;
704     window->context.swapInterval = swapIntervalWGL;
705     window->context.extensionSupported = extensionSupportedWGL;
706     window->context.getProcAddress = getProcAddressWGL;
707     window->context.destroy = destroyContextWGL;
708 
709     return GLFW_TRUE;
710 }
711 
712 #undef setAttrib
713 
714 
715 //////////////////////////////////////////////////////////////////////////
716 //////                        GLFW native API                       //////
717 //////////////////////////////////////////////////////////////////////////
718 
glfwGetWGLContext(GLFWwindow * handle)719 GLFWAPI HGLRC glfwGetWGLContext(GLFWwindow* handle)
720 {
721     _GLFWwindow* window = (_GLFWwindow*) handle;
722     _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
723 
724     if (window->context.client == GLFW_NO_API)
725     {
726         _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
727         return NULL;
728     }
729 
730     return window->context.wgl.handle;
731 }
732 
733