moveto.c

/* I wrote this in 1990. I was at the time very proud of replacing two 
 * pages of Pascal code with an inner loop that was basically three lines.
 *
 * Today, I would... not do it this way.
 * -seebs
 *
 * For meditation: http://thecodelesscode.com/case/13
 */
void
moveto(int *x, int *y, int tx, int ty) {
  int dev,sx,sy;
  int *g,*l,li,gi,sl,sg;

  gi=abs(tx-*x); li=abs(ty-*y);
  sx=sign(tx-*x); sy=sign(ty-*y);
  if(gi > li) {
    g=x; l=y; sl=sy; sg=sx;
  } else {
    g=y; l=x; dev=li; li=gi; gi=dev; sl=sx; sg=sy;
  }
  dev=0;
  do { dev+=(li << 1); *g+=sg;
        if(dev>gi) { dev-=(gi << 1); *l += sl; }
  } while(!(*x==tx && *y==ty) && !loc_solid(*x,*y));
}