+ /* TODO: do this with QueryPerformanceCounter as timeGetTime has
+ * insufficient resolution (only about 5 ms on system under low load).
+ * See:
+ * http://msdn.microsoft.com/en-us/library/windows/desktop/dd757629(v=vs.85).aspx
+ * Or maybe QueryPerformanceCounter is not a good idea either, see
+ * http://old.nabble.com/Re%3A-glutTimerFunc-does-not-detect-if-system-time-moved-backward-p33479674.html
+ * for some other ideas (at bottom)...
+ */