src/track.c

   1 /*      SCCS Id: @(#)track.c    3.4     87/08/08        */
   2 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
   3 /* NetHack may be freely redistributed.  See license for details. */
   4 /* track.c - version 1.0.2 */
   5
   6 #include "hack.h"
   7
   8 #define UTSZ    50
   9
  10 STATIC_VAR NEARDATA int utcnt, utpnt;
  11 STATIC_VAR NEARDATA coord utrack[UTSZ];
  12
  13 #ifdef OVLB
  14
  15 void
  16 initrack()
  17 {
  18         utcnt = utpnt = 0;
  19 }
  20
  21 #endif /* OVLB */
  22 #ifdef OVL1
  23
  24 /* add to track */
  25 void
  26 settrack()
  27 {
  28         if(utcnt < UTSZ) utcnt++;
  29         if(utpnt == UTSZ) utpnt = 0;
  30         utrack[utpnt].x = u.ux;
  31         utrack[utpnt].y = u.uy;
  32         utpnt++;
  33 }
  34
  35 #endif /* OVL1 */
  36 #ifdef OVL0
  37
  38 coord *
  39 gettrack(x, y)
  40 register int x, y;
  41 {
  42     register int cnt, ndist;
  43     register coord *tc;
  44     cnt = utcnt;
  45     for(tc = &utrack[utpnt]; cnt--; ){
  46         if(tc == utrack) tc = &utrack[UTSZ-1];
  47         else tc--;
  48         ndist = distmin(x,y,tc->x,tc->y);
  49
  50         /* if far away, skip track entries til we're closer */
  51         if(ndist > 2) {
  52             ndist -= 2; /* be careful due to extra decrement at top of loop */
  53             cnt -= ndist;
  54             if(cnt <= 0)
  55                 return (coord *) 0; /* too far away, no matches possible */
  56             if(tc < &utrack[ndist])
  57                 tc += (UTSZ-ndist);
  58             else
  59                 tc -= ndist;
  60         } else if(ndist <= 1)
  61             return(ndist ? tc : 0);
  62     }
  63     return (coord *)0;
  64 }
  65
  66 #endif /* OVL0 */
  67
  68 /*track.c*/