Function flip_encoded_dir_bits

src/sp_lev.c:498–514

transpose an encoded direction */

/* transpose an encoded direction */
staticfn int
flip_encoded_dir_bits(int flp, int val)
{
    /* these depend on xdir[] and ydir[] order */
    if (flp & 1) {
        val = swapbits(val, 1, 7);
        val = swapbits(val, 2, 6);
        val = swapbits(val, 3, 5);
    }
    if (flp & 2) {
        val = swapbits(val, 1, 3);
        val = swapbits(val, 0, 4);
        val = swapbits(val, 7, 5);
    }

    return val;
}

#define FlipX(val) ((maxx - (val)) + minx)
#define FlipY(val) ((maxy - (val)) + miny)