medfall

A super great game engine
Log | Files | Refs

wgl_context.cc (24689B)


      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 //
     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 //
     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             PIXELFORMATDESCRIPTOR pfd;
    156 
    157             // Get pixel format attributes through legacy PFDs
    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 
    232 // Returns whether desktop compositing is enabled
    233 //
    234 static GLFWbool isCompositionEnabled(void)
    235 {
    236     BOOL enabled;
    237 
    238     if (!_glfw_DwmIsCompositionEnabled)
    239         return FALSE;
    240 
    241     if (_glfw_DwmIsCompositionEnabled(&enabled) != S_OK)
    242         return FALSE;
    243 
    244     return enabled;
    245 }
    246 
    247 static void makeContextCurrentWGL(_GLFWwindow* window)
    248 {
    249     if (window)
    250     {
    251         if (wglMakeCurrent(window->context.wgl.dc, window->context.wgl.handle))
    252             _glfwPlatformSetTls(&_glfw.contextSlot, window);
    253         else
    254         {
    255             _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    256                                  "WGL: Failed to make context current");
    257             _glfwPlatformSetTls(&_glfw.contextSlot, NULL);
    258         }
    259     }
    260     else
    261     {
    262         if (!wglMakeCurrent(NULL, NULL))
    263         {
    264             _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    265                                  "WGL: Failed to clear current context");
    266         }
    267 
    268         _glfwPlatformSetTls(&_glfw.contextSlot, NULL);
    269     }
    270 }
    271 
    272 static void swapBuffersWGL(_GLFWwindow* window)
    273 {
    274     // HACK: Use DwmFlush when desktop composition is enabled
    275     if (isCompositionEnabled() && !window->monitor)
    276     {
    277         int count = abs(window->context.wgl.interval);
    278         while (count--)
    279             _glfw_DwmFlush();
    280     }
    281 
    282     SwapBuffers(window->context.wgl.dc);
    283 }
    284 
    285 static void swapIntervalWGL(int interval)
    286 {
    287     _GLFWwindow* window = _glfwPlatformGetTls(&_glfw.contextSlot);
    288 
    289     window->context.wgl.interval = interval;
    290 
    291     // HACK: Disable WGL swap interval when desktop composition is enabled to
    292     //       avoid interfering with DWM vsync
    293     if (isCompositionEnabled() && !window->monitor)
    294         interval = 0;
    295 
    296     if (_glfw.wgl.EXT_swap_control)
    297         _glfw.wgl.SwapIntervalEXT(interval);
    298 }
    299 
    300 static int extensionSupportedWGL(const char* extension)
    301 {
    302     const char* extensions;
    303 
    304     if (_glfw.wgl.GetExtensionsStringEXT)
    305     {
    306         extensions = _glfw.wgl.GetExtensionsStringEXT();
    307         if (extensions)
    308         {
    309             if (_glfwStringInExtensionString(extension, extensions))
    310                 return GLFW_TRUE;
    311         }
    312     }
    313 
    314     if (_glfw.wgl.GetExtensionsStringARB)
    315     {
    316         extensions = _glfw.wgl.GetExtensionsStringARB(wglGetCurrentDC());
    317         if (extensions)
    318         {
    319             if (_glfwStringInExtensionString(extension, extensions))
    320                 return GLFW_TRUE;
    321         }
    322     }
    323 
    324     return GLFW_FALSE;
    325 }
    326 
    327 static GLFWglproc getProcAddressWGL(const char* procname)
    328 {
    329     const GLFWglproc proc = (GLFWglproc) wglGetProcAddress(procname);
    330     if (proc)
    331         return proc;
    332 
    333     return (GLFWglproc) GetProcAddress(_glfw.wgl.instance, procname);
    334 }
    335 
    336 // Destroy the OpenGL context
    337 //
    338 static void destroyContextWGL(_GLFWwindow* window)
    339 {
    340     if (window->context.wgl.handle)
    341     {
    342         wglDeleteContext(window->context.wgl.handle);
    343         window->context.wgl.handle = NULL;
    344     }
    345 }
    346 
    347 // Initialize WGL-specific extensions
    348 //
    349 static void loadWGLExtensions(void)
    350 {
    351     PIXELFORMATDESCRIPTOR pfd;
    352     HGLRC rc;
    353     HDC dc = GetDC(_glfw.win32.helperWindowHandle);;
    354 
    355     _glfw.wgl.extensionsLoaded = GLFW_TRUE;
    356 
    357     // NOTE: A dummy context has to be created for opengl32.dll to load the
    358     //       OpenGL ICD, from which we can then query WGL extensions
    359     // NOTE: This code will accept the Microsoft GDI ICD; accelerated context
    360     //       creation failure occurs during manual pixel format enumeration
    361 
    362     ZeroMemory(&pfd, sizeof(pfd));
    363     pfd.nSize = sizeof(pfd);
    364     pfd.nVersion = 1;
    365     pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
    366     pfd.iPixelType = PFD_TYPE_RGBA;
    367     pfd.cColorBits = 24;
    368 
    369     if (!SetPixelFormat(dc, ChoosePixelFormat(dc, &pfd), &pfd))
    370     {
    371         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    372                              "WGL: Failed to set pixel format for dummy context");
    373         return;
    374     }
    375 
    376     rc = wglCreateContext(dc);
    377     if (!rc)
    378     {
    379         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    380                              "WGL: Failed to create dummy context");
    381         return;
    382     }
    383 
    384     if (!wglMakeCurrent(dc, rc))
    385     {
    386         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    387                              "WGL: Failed to make dummy context current");
    388         wglDeleteContext(rc);
    389         return;
    390     }
    391 
    392     // NOTE: Functions must be loaded first as they're needed to retrieve the
    393     //       extension string that tells us whether the functions are supported
    394     _glfw.wgl.GetExtensionsStringEXT = (PFNWGLGETEXTENSIONSSTRINGEXTPROC)
    395         wglGetProcAddress("wglGetExtensionsStringEXT");
    396     _glfw.wgl.GetExtensionsStringARB = (PFNWGLGETEXTENSIONSSTRINGARBPROC)
    397         wglGetProcAddress("wglGetExtensionsStringARB");
    398     _glfw.wgl.CreateContextAttribsARB = (PFNWGLCREATECONTEXTATTRIBSARBPROC)
    399         wglGetProcAddress("wglCreateContextAttribsARB");
    400     _glfw.wgl.SwapIntervalEXT = (PFNWGLSWAPINTERVALEXTPROC)
    401         wglGetProcAddress("wglSwapIntervalEXT");
    402     _glfw.wgl.GetPixelFormatAttribivARB = (PFNWGLGETPIXELFORMATATTRIBIVARBPROC)
    403         wglGetProcAddress("wglGetPixelFormatAttribivARB");
    404 
    405     // NOTE: WGL_ARB_extensions_string and WGL_EXT_extensions_string are not
    406     //       checked below as we are already using them
    407     _glfw.wgl.ARB_multisample =
    408         extensionSupportedWGL("WGL_ARB_multisample");
    409     _glfw.wgl.ARB_framebuffer_sRGB =
    410         extensionSupportedWGL("WGL_ARB_framebuffer_sRGB");
    411     _glfw.wgl.EXT_framebuffer_sRGB =
    412         extensionSupportedWGL("WGL_EXT_framebuffer_sRGB");
    413     _glfw.wgl.ARB_create_context =
    414         extensionSupportedWGL("WGL_ARB_create_context");
    415     _glfw.wgl.ARB_create_context_profile =
    416         extensionSupportedWGL("WGL_ARB_create_context_profile");
    417     _glfw.wgl.EXT_create_context_es2_profile =
    418         extensionSupportedWGL("WGL_EXT_create_context_es2_profile");
    419     _glfw.wgl.ARB_create_context_robustness =
    420         extensionSupportedWGL("WGL_ARB_create_context_robustness");
    421     _glfw.wgl.ARB_create_context_no_error =
    422         extensionSupportedWGL("WGL_ARB_create_context_no_error");
    423     _glfw.wgl.EXT_swap_control =
    424         extensionSupportedWGL("WGL_EXT_swap_control");
    425     _glfw.wgl.EXT_colorspace =
    426         extensionSupportedWGL("WGL_EXT_colorspace");
    427     _glfw.wgl.ARB_pixel_format =
    428         extensionSupportedWGL("WGL_ARB_pixel_format");
    429     _glfw.wgl.ARB_context_flush_control =
    430         extensionSupportedWGL("WGL_ARB_context_flush_control");
    431 
    432     wglMakeCurrent(dc, NULL);
    433     wglDeleteContext(rc);
    434 }
    435 
    436 
    437 //////////////////////////////////////////////////////////////////////////
    438 //////                       GLFW internal API                      //////
    439 //////////////////////////////////////////////////////////////////////////
    440 
    441 // Initialize WGL
    442 //
    443 GLFWbool _glfwInitWGL(void)
    444 {
    445     if (_glfw.wgl.instance)
    446         return GLFW_TRUE;
    447 
    448     _glfw.wgl.instance = LoadLibraryA("opengl32.dll");
    449     if (!_glfw.wgl.instance)
    450     {
    451         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    452                              "WGL: Failed to load opengl32.dll");
    453         return GLFW_FALSE;
    454     }
    455 
    456     _glfw.wgl.CreateContext = (PFN_wglCreateContext)
    457         GetProcAddress(_glfw.wgl.instance, "wglCreateContext");
    458     _glfw.wgl.DeleteContext = (PFN_wglDeleteContext)
    459         GetProcAddress(_glfw.wgl.instance, "wglDeleteContext");
    460     _glfw.wgl.GetProcAddress = (PFN_wglGetProcAddress)
    461         GetProcAddress(_glfw.wgl.instance, "wglGetProcAddress");
    462     _glfw.wgl.GetCurrentDC = (PFN_wglGetCurrentDC)
    463         GetProcAddress(_glfw.wgl.instance, "wglGetCurrentDC");
    464     _glfw.wgl.MakeCurrent = (PFN_wglMakeCurrent)
    465         GetProcAddress(_glfw.wgl.instance, "wglMakeCurrent");
    466     _glfw.wgl.ShareLists = (PFN_wglShareLists)
    467         GetProcAddress(_glfw.wgl.instance, "wglShareLists");
    468 
    469     return GLFW_TRUE;
    470 }
    471 
    472 // Terminate WGL
    473 //
    474 void _glfwTerminateWGL(void)
    475 {
    476     if (_glfw.wgl.instance)
    477         FreeLibrary(_glfw.wgl.instance);
    478 }
    479 
    480 #define setAttrib(a, v) \
    481 { \
    482     assert((size_t) (index + 1) < sizeof(attribs) / sizeof(attribs[0])); \
    483     attribs[index++] = a; \
    484     attribs[index++] = v; \
    485 }
    486 
    487 // Create the OpenGL or OpenGL ES context
    488 //
    489 GLFWbool _glfwCreateContextWGL(_GLFWwindow* window,
    490                                const _GLFWctxconfig* ctxconfig,
    491                                const _GLFWfbconfig* fbconfig)
    492 {
    493     int attribs[40];
    494     int pixelFormat;
    495     PIXELFORMATDESCRIPTOR pfd;
    496     HGLRC share = NULL;
    497 
    498     if (!_glfw.wgl.extensionsLoaded)
    499         loadWGLExtensions();
    500 
    501     if (ctxconfig->share)
    502         share = ctxconfig->share->context.wgl.handle;
    503 
    504     window->context.wgl.dc = GetDC(window->win32.handle);
    505     if (!window->context.wgl.dc)
    506     {
    507         _glfwInputError(GLFW_PLATFORM_ERROR,
    508                         "WGL: Failed to retrieve DC for window");
    509         return GLFW_FALSE;
    510     }
    511 
    512     pixelFormat = choosePixelFormat(window, ctxconfig, fbconfig);
    513     if (!pixelFormat)
    514         return GLFW_FALSE;
    515 
    516     if (!DescribePixelFormat(window->context.wgl.dc,
    517                              pixelFormat, sizeof(pfd), &pfd))
    518     {
    519         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    520                              "WGL: Failed to retrieve PFD for selected pixel format");
    521         return GLFW_FALSE;
    522     }
    523 
    524     if (!SetPixelFormat(window->context.wgl.dc, pixelFormat, &pfd))
    525     {
    526         _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    527                              "WGL: Failed to set selected pixel format");
    528         return GLFW_FALSE;
    529     }
    530 
    531     if (ctxconfig->client == GLFW_OPENGL_API)
    532     {
    533         if (ctxconfig->forward)
    534         {
    535             if (!_glfw.wgl.ARB_create_context)
    536             {
    537                 _glfwInputError(GLFW_VERSION_UNAVAILABLE,
    538                                 "WGL: A forward compatible OpenGL context requested but WGL_ARB_create_context is unavailable");
    539                 return GLFW_FALSE;
    540             }
    541         }
    542 
    543         if (ctxconfig->profile)
    544         {
    545             if (!_glfw.wgl.ARB_create_context_profile)
    546             {
    547                 _glfwInputError(GLFW_VERSION_UNAVAILABLE,
    548                                 "WGL: OpenGL profile requested but WGL_ARB_create_context_profile is unavailable");
    549                 return GLFW_FALSE;
    550             }
    551         }
    552     }
    553     else
    554     {
    555         if (!_glfw.wgl.ARB_create_context ||
    556             !_glfw.wgl.ARB_create_context_profile ||
    557             !_glfw.wgl.EXT_create_context_es2_profile)
    558         {
    559             _glfwInputError(GLFW_API_UNAVAILABLE,
    560                             "WGL: OpenGL ES requested but WGL_ARB_create_context_es2_profile is unavailable");
    561             return GLFW_FALSE;
    562         }
    563     }
    564 
    565     if (_glfw.wgl.ARB_create_context)
    566     {
    567         int index = 0, mask = 0, flags = 0;
    568 
    569         if (ctxconfig->client == GLFW_OPENGL_API)
    570         {
    571             if (ctxconfig->forward)
    572                 flags |= WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB;
    573 
    574             if (ctxconfig->profile == GLFW_OPENGL_CORE_PROFILE)
    575                 mask |= WGL_CONTEXT_CORE_PROFILE_BIT_ARB;
    576             else if (ctxconfig->profile == GLFW_OPENGL_COMPAT_PROFILE)
    577                 mask |= WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB;
    578         }
    579         else
    580             mask |= WGL_CONTEXT_ES2_PROFILE_BIT_EXT;
    581 
    582         if (ctxconfig->debug)
    583             flags |= WGL_CONTEXT_DEBUG_BIT_ARB;
    584 
    585         if (ctxconfig->robustness)
    586         {
    587             if (_glfw.wgl.ARB_create_context_robustness)
    588             {
    589                 if (ctxconfig->robustness == GLFW_NO_RESET_NOTIFICATION)
    590                 {
    591                     setAttrib(WGL_CONTEXT_RESET_NOTIFICATION_STRATEGY_ARB,
    592                               WGL_NO_RESET_NOTIFICATION_ARB);
    593                 }
    594                 else if (ctxconfig->robustness == GLFW_LOSE_CONTEXT_ON_RESET)
    595                 {
    596                     setAttrib(WGL_CONTEXT_RESET_NOTIFICATION_STRATEGY_ARB,
    597                               WGL_LOSE_CONTEXT_ON_RESET_ARB);
    598                 }
    599 
    600                 flags |= WGL_CONTEXT_ROBUST_ACCESS_BIT_ARB;
    601             }
    602         }
    603 
    604         if (ctxconfig->release)
    605         {
    606             if (_glfw.wgl.ARB_context_flush_control)
    607             {
    608                 if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_NONE)
    609                 {
    610                     setAttrib(WGL_CONTEXT_RELEASE_BEHAVIOR_ARB,
    611                               WGL_CONTEXT_RELEASE_BEHAVIOR_NONE_ARB);
    612                 }
    613                 else if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_FLUSH)
    614                 {
    615                     setAttrib(WGL_CONTEXT_RELEASE_BEHAVIOR_ARB,
    616                               WGL_CONTEXT_RELEASE_BEHAVIOR_FLUSH_ARB);
    617                 }
    618             }
    619         }
    620 
    621         if (ctxconfig->noerror)
    622         {
    623             if (_glfw.wgl.ARB_create_context_no_error)
    624                 setAttrib(WGL_CONTEXT_OPENGL_NO_ERROR_ARB, GLFW_TRUE);
    625         }
    626 
    627         // NOTE: Only request an explicitly versioned context when necessary, as
    628         //       explicitly requesting version 1.0 does not always return the
    629         //       highest version supported by the driver
    630         if (ctxconfig->major != 1 || ctxconfig->minor != 0)
    631         {
    632             setAttrib(WGL_CONTEXT_MAJOR_VERSION_ARB, ctxconfig->major);
    633             setAttrib(WGL_CONTEXT_MINOR_VERSION_ARB, ctxconfig->minor);
    634         }
    635 
    636         if (flags)
    637             setAttrib(WGL_CONTEXT_FLAGS_ARB, flags);
    638 
    639         if (mask)
    640             setAttrib(WGL_CONTEXT_PROFILE_MASK_ARB, mask);
    641 
    642         setAttrib(0, 0);
    643 
    644         window->context.wgl.handle =
    645             _glfw.wgl.CreateContextAttribsARB(window->context.wgl.dc,
    646                                               share, attribs);
    647         if (!window->context.wgl.handle)
    648         {
    649             const DWORD error = GetLastError();
    650 
    651             if (error == (0xc0070000 | ERROR_INVALID_VERSION_ARB))
    652             {
    653                 if (ctxconfig->client == GLFW_OPENGL_API)
    654                 {
    655                     _glfwInputError(GLFW_VERSION_UNAVAILABLE,
    656                                     "WGL: Driver does not support OpenGL version %i.%i",
    657                                     ctxconfig->major,
    658                                     ctxconfig->minor);
    659                 }
    660                 else
    661                 {
    662                     _glfwInputError(GLFW_VERSION_UNAVAILABLE,
    663                                     "WGL: Driver does not support OpenGL ES version %i.%i",
    664                                     ctxconfig->major,
    665                                     ctxconfig->minor);
    666                 }
    667             }
    668             else if (error == (0xc0070000 | ERROR_INVALID_PROFILE_ARB))
    669             {
    670                 _glfwInputError(GLFW_VERSION_UNAVAILABLE,
    671                                 "WGL: Driver does not support the requested OpenGL profile");
    672             }
    673             else if (error == (0xc0070000 | ERROR_INCOMPATIBLE_DEVICE_CONTEXTS_ARB))
    674             {
    675                 _glfwInputError(GLFW_INVALID_VALUE,
    676                                 "WGL: The share context is not compatible with the requested context");
    677             }
    678             else
    679             {
    680                 if (ctxconfig->client == GLFW_OPENGL_API)
    681                 {
    682                     _glfwInputError(GLFW_VERSION_UNAVAILABLE,
    683                                     "WGL: Failed to create OpenGL context");
    684                 }
    685                 else
    686                 {
    687                     _glfwInputError(GLFW_VERSION_UNAVAILABLE,
    688                                     "WGL: Failed to create OpenGL ES context");
    689                 }
    690             }
    691 
    692             return GLFW_FALSE;
    693         }
    694     }
    695     else
    696     {
    697         window->context.wgl.handle = wglCreateContext(window->context.wgl.dc);
    698         if (!window->context.wgl.handle)
    699         {
    700             _glfwInputErrorWin32(GLFW_VERSION_UNAVAILABLE,
    701                                  "WGL: Failed to create OpenGL context");
    702             return GLFW_FALSE;
    703         }
    704 
    705         if (share)
    706         {
    707             if (!wglShareLists(share, window->context.wgl.handle))
    708             {
    709                 _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
    710                                      "WGL: Failed to enable sharing with specified OpenGL context");
    711                 return GLFW_FALSE;
    712             }
    713         }
    714     }
    715 
    716     window->context.makeCurrent = makeContextCurrentWGL;
    717     window->context.swapBuffers = swapBuffersWGL;
    718     window->context.swapInterval = swapIntervalWGL;
    719     window->context.extensionSupported = extensionSupportedWGL;
    720     window->context.getProcAddress = getProcAddressWGL;
    721     window->context.destroy = destroyContextWGL;
    722 
    723     return GLFW_TRUE;
    724 }
    725 
    726 #undef setAttrib
    727 
    728 
    729 //////////////////////////////////////////////////////////////////////////
    730 //////                        GLFW native API                       //////
    731 //////////////////////////////////////////////////////////////////////////
    732 
    733 GLFWAPI HGLRC glfwGetWGLContext(GLFWwindow* handle)
    734 {
    735     _GLFWwindow* window = (_GLFWwindow*) handle;
    736     _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
    737 
    738     if (window->context.client == GLFW_NO_API)
    739     {
    740         _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
    741         return NULL;
    742     }
    743 
    744     return window->context.wgl.handle;
    745 }
    746