-extern float xscroll, yscroll;
-extern float yscroll;
-extern float scrollvel;
-
-// 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)