__GLXextFuncPtr get_gl_proc_address(const QString &procName)
{
    __GLXextFuncPtr ret = NULL;

#if GLX_VERSION_1_4
    X11S(ret = glXGetProcAddress((const GLubyte*)procName.latin1()));
#elif GLX_ARB_get_proc_address
    X11S(ret = glXGetProcAddressARB((const GLubyte*)procName.latin1()));
#elif GLX_EXT_get_proc_address
    X11S(ret = glXGetProcAddressEXT((const GLubyte*)procName.latin1()));
#endif

    return ret;
}