fix: force a complete QBVH rebuild when it gets too imbalanced. #185
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In many situations (see linked issues), especially at the first simulation frame, but also if many objects are inserted at once during the simulation, the QBVH incremental update algorithm could lead to a degenerate tree. Ideally the fix would improve the incremental update to lower risks of imbalance, but this is a very difficult problem.
A way simpler, but less efficient, fix (that is implemented in this PR) is to force a complete tree rebuild if it reaches a certain depth, indicating degeneracy. That depth is set to 15, which for a perfectly balanced QBVH, can hold
4^15 = 1.073.741.824leaves (meaning that past that number of object in the tree you are guaranteed to trigger a forced rebuild at every update. But this is a very unlikely number to reach in practical games).Fix #146
Close #169
Fix dimforge/rapier#466
Fix dimforge/rapier#532
Fix dimforge/rapier#558
Fix dimforge/rapier#450