- SquareDelta ray_direction(Square orig, Square dest) {
-
- int df = file_distance(orig, dest);
- int dr = rank_distance(orig, dest);
-
- if (orig != dest && (!df || !dr || df == dr))
- return SquareDelta(dest - orig) / Max(df, dr);
-
- return DELTA_NONE;
- }
-