-// all movement is based on s_frame.
-float t_frame; // length of this frame (in ticks = 1/20th second)
-int ms_frame; // length of this frame (milliseconds)
-int ms_end; // end of this frame (milliseconds)
+// 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)