-/*
- * Elapsed Time
- */
-long fgElapsedTime( void )
-{
- if ( fgState.Time.Set )
- {
-#if TARGET_HOST_POSIX_X11
- struct timeval now;
- long elapsed;
-
- gettimeofday( &now, NULL );
-
- elapsed = (now.tv_usec - fgState.Time.Value.tv_usec) / 1000;
- elapsed += (now.tv_sec - fgState.Time.Value.tv_sec) * 1000;
-
- return elapsed;
+
+/* Platform-dependent time in milliseconds, as an unsigned 32-bit integer.
+ * This value wraps every 49.7 days, but integer overflows cancel
+ * when subtracting an initial start time, unless the total time exceeds
+ * 32-bit, where the GLUT API return value is also overflowed.
+ */
+unsigned long fgSystemTime(void) {
+#if HAVE_GETTIMEOFDAY
+ struct timeval now;
+ gettimeofday( &now, NULL );
+ return now.tv_usec/1000 + now.tv_sec*1000;