Actors with particle systems have oversized bounding spheres

AnyOldName3
2026-03-29T17:03:50Z

Discovered in the comments of https://gitlab.com/OpenMW/openmw/-/merge_requests/5175, and possibly the main thing making it faster than the master branch.

Discussion in this thread: https://gitlab.com/OpenMW/openmw/-/merge_requests/5175/diffs#note_3122204034

I haven't got to the bottom of what's going on. I *think* there's some mismatch of model-space bounds and world-space bounds at some point (e.g. setting a particle system's bounds to include things in both spaces) and possibly also not removing expired particles so, e.g. if an actor carries a torch with smoke particles, their bounds end up containing everywhere they've ever carried the torch to.