mLastBuildRevision == mRevision with current use cases does not happen. But
even if this will happen when another use case will be added it does not save
much computation. The most expensive operation is not adding objects to the
MeshBuilder but to optimize resulting navmesh that will happen anyway in
MeshBuilder::create call.
Use LRU modification to hold currently used items. Use RecastMesh binary
data for item key.
Store original pointer of btCollisionShape in user pointer to make available
it as an identifier within all duplicates. Use pointer to heights data array
for btHeightfieldTerrainShape.
elsid
Bret Curtis
Andrei Kortunov