[3.x] Fix physics BVH broadphase update when changing collision layer/mask #54108
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pouleyKetchoupp
commented
Oct 21, 2021
| typename BVHTREE_CLASS::ItemExtra &exb = tree._extra[p_to.id()]; | ||
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| // if the userdata is the same, no collisions should occur | ||
| if ((exa.userdata == exb.userdata) && exa.userdata) { |
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@lawnjelly I'm not 100% sure this condition is needed here, same with _handle_sort above, but I've copied them from other functions that deal with pairing and it doesn't seem that it hurts.
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This was something I had to copy from the original octree, there were some cases were duplicates were added by the client code, and they caused crashes if they collided with themselves. So it probably is safer to keep it in.
The BVH implementation is not checking collision layers on existing pairs on move like other physics broadphases do. This is solved by adding a new call to trigger pair callbacks again so the physics engine can check layers again (specific to the BVH version, other broadphase implementations just trigger a move like before).
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Looks good in terms of the code, I just want to test it, couldn't download the artifacts for some reason so will have to build from source. |
lawnjelly
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Oct 22, 2021
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Thanks! |
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The BVH implementation is not checking collision layers on existing pairs on move like other physics broadphases do.
This is solved by adding a new call to trigger pair callbacks again so the physics engine can check layers again (specific to the BVH version, other broadphase implementations just trigger a move like before).
It looks like a lot of file changes but active code changes are actually well contained to limit potential regressions.
Fixes #53997 for 3.4.
For 4.0 and 3.5, a cleaner approach will be used but it will be a wider change that will need more time for tests (see #53997 (comment)).