Function get_offset

Python/dijkstra.py:18–24

(index)

# returns (y, x), index is 0-3 referencing north-west
def get_offset(index):
    return [
        (-1, 0), # north
        (0, 1), # east
        (1, 0), # south
        (0, -1) # west
    ][index]

# the opposite direction's index
def get_opposite_index(index):