Support with btDefaultCollisionConfiguration

[Levi-Armstrong]

I am using Bullet for collision checking in robotic path planning. I have noticed that when creating btDefaultCollisionConfiguration object it allocates around 7MB mostly when it creates the two btPoolAllocator. Now I noticed that the default max size for the collision algorithm pool and persistent manifold pool is 4096. What is the implications if this was reduced? Also notice that it supports passing the pools in with the config. Can these pools be shared between multiple btDefaultCollisionConfiguration/btCollisionDispatcher?

[Levi-Armstrong]

For the purpose of testing I reduced the max size from 4096 to 100 and a unit test I have which create multiple clones of the contact checker one per thread and the memory was reduced 28MB.

[Levi-Armstrong]

For a single instance reducing it from 4096 to 100 take it form ~7MB to 0B but not sure what implications this has.

Comparison:

Before:

After:

[Levi-Armstrong]

Setting the max size to 500 allocates around 900kB