GLX_SGIX_swap_barrier http://oss.sgi.com/projects/ogl-sample/registry/SGIX/swap_barrier.txt GLX_SGIX_swap_barrier void glXBindSwapBarrierSGIX (Display *dpy, GLXDrawable drawable, int barrier) Bool glXQueryMaxSwapBarriersSGIX (Display *dpy, int screen, int *max)