fn walk_in_all_dirs(
    sim: &WorldSim,
    bridge: Option<Vec2<i32>>,
    a: Vec2<i32>
) -> [Option<(Vec2<i32>, f32)>; 8]
Expand description

Return Some if travel between a location and a chunk next to it is permitted If permitted, the approximate relative const of traversal is given Return tuple: (final location, cost)

For efficiency, this computes for all 8 directions at once.