FCollisionConstraintAllocator

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All constraint pointers are persistent in memory until Destroy() is called, or until they are pruned.

This allocator maintains the set of all overlapping particle pairs, with each overlapping particle pair managed by a FParticlePairMidPhase object. the MidPhase object is what actually calls the Narrow Phase and maintains the set of collision constraints for all the shape pairs on the particles.

Constraints are allocated during the collision detection phase and retained between ticks. An attempt to create a constraint for the same shape pair as seen on the previous tick will return the existing collision constraint with all of its data intact.

The allocator also keeps a list of Standard and Swept collision constraints that are active for the current tick. This list gets reset and rebuilt every frame during collision detection. It may get added to by the IslandManager if some islands are woken following collision detection.

The allocators Epoch counter is used to determine whether a constraint (or midphase object) generated any contacts for the current frame. When a midphase creates or updates a constraint, it copies the current Epoch counter.

The Midphase list is pruned at the end of each tick so if particles are destroyed or a particle pair is no longer overlapping, the collisions will be destroyed.

When particles are destroyed, we do not immediately destroy the MidPhases (or Collisions) that are associoated with the particle. Instead, we clear the particle pointer from them, but leave their destruction to the pruning process. This avoids the need to parse collision and midphase lists whenever a particle is disabled.

NOTE: To reduce RBAN memory use, we do not create any collision blocks until the first call to CreateCollisionConstraint (see ConstraintPool initialization)

Syntax

class FCollisionConstraintAllocator  
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class FCollisionConstraintAllocator

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