Function DirDifference

src/direction_func.h:68–75

* Calculate the difference between two directions * * @param d0 The first direction as the base * @param d1 The second direction as the offset from the base * @return The difference how the second direction drifts of the first one. */

 * @return The difference how the second direction drifts of the first one.
 */
inline DirDiff DirDifference(Direction d0, Direction d1)
{
	assert(IsValidDirection(d0));
	assert(IsValidDirection(d1));
	/* Cast to uint so compiler can use bitmask. If the difference is negative
	 * and we used int instead of uint, further "+ 8" would have to be added. */
	return static_cast<DirDiff>((static_cast<uint>(d0) - static_cast<uint>(d1)) % 8);
}

/**
 * Applies two differences together