Get the contact point of a rigid body.

[sio2interactive]

It may be obvious but I really can't see it... How can I get if a rigid body is currently colliding with another and get the contact point world position and its normal.

In other words pretty much what a btCollisionWorld::ClosestRayResultCallback does but that I can get directly from an arbitrary rigid body.


Tks in advance,

Cheers,

[pico]

Hi,

check out the callback section in the Wiki.

[Erwin Coumans]

A contact point doesn't belong to a single rigid body. You always need a pair of rigid bodies for contact. Contacts (points) are stored in persistent manifold structures, owned by a collision algorithm/overlapping pair.

Here are a few methods to get access to contact points, sorted from easy to harder to implement:

• Implement a contact added/process/removed callback
• Iterate over all contact manifolds, and take the one you need, see Bullet/Demos/CollisionInterfaceDemo
• If you have two rigid bodies, you can lookup if an overlapping pair exists, and iterate over their contact manifold(s).
• Use the btPairCachingGhostObject to keep track of all overlapping bodies and pairs for a particular body. Then just iterate over the contact manifolds.

Hope this helps,
Erwin