glutSwapBuffers - swaps the buffers of the current window if double buffered.
void glutSwapBuffers(void);
Performs a buffer swap on the layer in use for the current window. Specifically,
glutSwapBuffers promotes the contents of the back buffer of the layer in use
of the current window to become the contents of the front buffer. The contents
of the back buffer then become undefined. The update typically takes place
during the vertical retrace of the monitor, rather than immediately after
glutSwapBuffers is called.
An implicit glFlush is done by glutSwapBuffers before it returns.
Subsequent OpenGL commands can be issued immediately after calling
glutSwapBuffers, but are not executed until the buffer exchange is
completed.
If the layer in use is not double buffered, glutSwapBuffers has no
effect.
glutPostRedisplay, glutDisplayFunc
Mark J. Kilgard (mjk@nvidia.com)