ContactResultCallback::addSingleResult clarification

[elojd]

Hello,

I need some clarification about ContactResultCallback::addSingleResult(btManifoldPoint& cp, ...).

1) The easiest first, what is the semantics of the return value (btScalar)? I've noticed that 1.0f or 0 are usually returned.

2) What are cp.m_positionWorldOnA and cp.m_positionWorldOnB?

3) What are cp.m_localPointOnA and cp.m_localPointOnB?

If you could point me to some sketch explaining these values, it will be greatly appreciated.

[Erwin Coumans]

There was a planned purpose for the return value of addSingleResult, but it is not used so you can ignore it.

The cp.m_positionWorldOnA is the position of the contact point on the surface of object A, same for B, both in world space. cp.m_localPointOnA are the local coordinates of that contact point.

For more details, see my GDC 2010 presentation about contact generation here (slide 14 might help): http://bullet.googlecode.com/files/GDC1 ... ontact.pdf

Thanks,
Erwin

[elojd]

Thanks. The presentation did help a lot.

[jokooon]

Thanks a lot, I'm glad to have found this.

Although I wonder if this functionnality really requires an abstract callback, for example if I needed a simple raycast, all I needed was to use the default one, which is already implemented.

[jokooon]

I've inherited ContactResultCallback and overriden addsingleresult, but MSVC 10 still tells me my inherited class is abstract, which was not the case in bullet 2.80.