extern char *initerror;
extern struct shape shipshape;
-extern float shipx,shipy; // X position, 0..XSIZE
-extern float shipdx,shipdy; // Change in X position per tick.
+extern float shipx,shipy; // ship position on screen
+extern float shipdx,shipdy; // ship speed (pixels/tick)
extern float screendx, screendy;
extern float xscroll, yscroll;
extern float yscroll;
extern float scrollvel;
-// all movement is based on s_frame.
+// All movement is based on t_frame.
+// All speeds are pixels/tick, with 20 ticks per second.
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;
extern float fadetimer, faderate;
extern int pausedown, paused;