Optimising LOS Algorithm

The code as it is works fine, but I would like to make it faster ... what can I do? I'm not afraid of ASM, but I can't really see what I could do that the compiler doesn't already do. BTW, the sight_blocked call has been replaced with a (map[x,y].flags && OPAQUE) == false, but I wanted to leave the original intact ... just in case

#define SGN(a)		((a<0) ? -1 : 1)

BOOL los(coord mx, coord my)
{
int t, x, y, ax, ay, sx, sy, dx, dy;
   dx = d.px - mx;
   dy = d.py - my;
   ax = abs(dx) << 1;
   ay = abs(dy) << 1;
   sx = SGN(dx);
   sy = SGN(dy);
   x = mx;
   y = my;
   if(ax > ay)
   {
      t = ay - (ax >> 1);
      do
      {
         if(t >= 0)
         {
            y += sy;
            t -= ax;
         }
         
         x += sx;
         t += ay;
         
         if x == d.px && y == d.py)
         {
            return TRUE;
         }
      while(sight_blocked(x,y) == FALSE);

      return FALSE;
   }
   else
   {
      // Y dominant loop

      t = ax - (ay >> 1);
      do
      {
         if(t >= 0)
         {
            x += sx;
            t -= ay;
         }
         y += sy;
         t += ax;
         if(x == d.px && y == d.py)
         {
            return TRUE;
         }
      }
      while(sight_blocked(x,y) == FALSE);
      return FALSE;
   }
}

------------------------------------------------- Mindphuq Software : "Who do you want to do today?" Edited by - morfe on 9/8/00 12:52:54 PM

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