// check for swap control functions
const char *extensions = glXQueryExtensionsString(display, DefaultScreen(display));
if (std::string(extensions).find("GLX_MESA_swap_control") != std::string::npos) {
// check for swap control functions
const char *extensions = glXQueryExtensionsString(display, DefaultScreen(display));
if (std::string(extensions).find("GLX_MESA_swap_control") != std::string::npos) {