It should be possible to define a spatial hash system based on a worldwidth/height and grid dimensions such that it doesn't cover the whole world (which could be huge, and contain mainy inactive chunks) that will present its grid with the tracked entity always at the center and report the positions of entities relative to it.
It should be possible to define a spatial hash system based on a worldwidth/height and grid dimensions such that it doesn't cover the whole world (which could be huge, and contain mainy inactive chunks) that will present its grid with the tracked entity always at the center and report the positions of entities relative to it.