On Fri, Apr 14, 2017 at 12:01:17PM -0700, Trent Piepho wrote: > I've got to wonder why some are offset by -90 degrees and some > aren't? Sign of y input. Most code has pattern atan2(x - mx, my - y), but code for torpedo guidance t_track in ntserv/daemon.c uses atan2(x - mx, y - my). Further uses of dy in t_track don't stop us from changing the sign in order to remove the offset. (t_near and t_explosion makes the same calculation of dy but there the sign does not matter.) -- James Cameron http://quozl.netrek.org/