-// all movement is based on s_frame.
-extern float t_frame; // length of this frame (in ticks = 1/20th second)
-extern float s_frame; // length of this frame (seconds)
-extern int ms_frame; // length of this frame (milliseconds)
-extern int ms_end; // end of this frame (milliseconds)
-
-extern int nships,score;
-extern int gameover;
-extern int maneuver;