Weighted distance between points along shortest paths.

State of legality of moves between adjacent points.

The minimal distance value assigned to paths that don't enter any unknown tiles.

The distance value that denotes no legal path between points, either due to blocked tiles or pathfinding aborted at earlier tiles, e.g., due to unknown tiles.

Fill out the given BFS array. Unsafe PointArray operations are OK here, because the intermediate values of the vector don't leak anywhere outside nor are kept unevaluated and so they can't be overwritten by the unsafe side-effect.

When computing move cost, we assume doors openable at no cost, because other actors use them, too, so the cost is shared and the extra visiblity is valuable, too. We treat unknown tiles specially. Whether suspect tiles are considered openable depends on smarkSuspect.

Find a path, without the source position, with the smallest length. The eps coefficient determines which direction (of the closest directions available) that path should prefer, where 0 means north-west and 1 means north.

Access a BFS array and interpret the looked up distance value.