GLX_EXT_swap_control http://www.opengl.org/registry/specs/EXT/swap_control.txt GLX_EXT_swap_control GLX_SWAP_INTERVAL_EXT 0x20F1 GLX_MAX_SWAP_INTERVAL_EXT 0x20F2 void glXSwapIntervalEXT (Display* dpy, GLXDrawable drawable, int interval)