src/glut/glx/glut_glxext.c

   1
   2 /* Copyright (c) Mark J. Kilgard, 1997. */
   3
   4 /* This program is freely distributable without licensing fees
   5    and is provided without guarantee or warrantee expressed or
   6    implied. This program is -not- in the public domain. */
   7
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include "glutint.h"
  11
  12 #if defined(GLX_VERSION_1_1)
  13 int
  14 __glutIsSupportedByGLX(char *extension)
  15 {
  16   static const char *extensions = NULL;
  17   const char *start;
  18   char *where, *terminator;
  19   int major, minor;
  20
  21   glXQueryVersion(__glutDisplay, &major, &minor);
  22   /* Be careful not to call glXQueryExtensionsString if it
  23      looks like the server doesn't support GLX 1.1.
  24      Unfortunately, the original GLX 1.0 didn't have the notion
  25      of GLX extensions. */
  26   if ((major == 1 && minor >= 1) || (major > 1)) {
  27     if (!extensions)
  28       extensions = glXQueryExtensionsString(__glutDisplay, __glutScreen);
  29     /* It takes a bit of care to be fool-proof about parsing
  30        the GLX extensions string.  Don't be fooled by
  31        sub-strings,  etc. */
  32     start = extensions;
  33     for (;;) {
  34       where = strstr(start, extension);
  35       if (!where)
  36         return 0;
  37       terminator = where + strlen(extension);
  38       if (where == start || *(where - 1) == ' ') {
  39         if (*terminator == ' ' || *terminator == '\0') {
  40           return 1;
  41         }
  42       }
  43       start = terminator;
  44     }
  45   }
  46   return 0;
  47 }
  48 #endif