The bin partitioning in ActorMap worked by dividing the map up into a few chunks of cells, each of which would contain some actors. Unfortunately, the bins were accessed directly in world coordinates which are on a scale 1024x greater than cell coordinates. This lead to all actors being placed into the bottom right bin. When checking for actors in a box, only this bottom right bin would be iterated for actors. Thanks to the fact this bin indeed contained all the actors, some clamps on the input ranges and filtering required per bin anyway, this actually returned correct results. Effectively, it was as if there was no spatial partitioning at all.
Not surprisingly however, this is fairly inefficient. By correcting the spatial partitioning to actually partition we see a 7x speedup in ActorsInBox on the RA shellmap.
a0737ccbf3