hack/hack.track.c

   1 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
   2 /* hack.track.c - version 1.0.2 */
   3
   4 #include "hack.h"
   5
   6 #define UTSZ    50
   7
   8 coord utrack[UTSZ];
   9 int utcnt = 0;
  10 int utpnt = 0;
  11
  12 initrack(){
  13         utcnt = utpnt = 0;
  14 }
  15
  16 /* add to track */
  17 settrack(){
  18         if(utcnt < UTSZ) utcnt++;
  19         if(utpnt == UTSZ) utpnt = 0;
  20         utrack[utpnt].x = u.ux;
  21         utrack[utpnt].y = u.uy;
  22         utpnt++;
  23 }
  24
  25 coord *
  26 gettrack(x,y) register x,y; {
  27 register int i,cnt,dist;
  28 coord tc;
  29         cnt = utcnt;
  30         for(i = utpnt-1; cnt--; i--){
  31                 if(i == -1) i = UTSZ-1;
  32                 tc = utrack[i];
  33                 dist = (x-tc.x)*(x-tc.x) + (y-tc.y)*(y-tc.y);
  34                 if(dist < 3)
  35                         return(dist ? &(utrack[i]) : 0);
  36         }
  37         return(0);
  38 }