btRigidBody angular factor

[rrck]

Hello,

I noticed some code in btRigidBody, which I can't understand. In applyImpulse() functions there is such code:

Code: Select all

if (m_angularFactor){...}

After last rbtRigidBody changes m_angularFactor become btVector3. I debug that code and it seems that btScalar*() operator is called in that if. Is that supposed behaviour? Sorry may be I don't understand something.

[Jasonrun]

As far as I can tell is that this is simply checking to make sure that the angular factor is not a null pointer before continuing.

[rrck]

As far as I can tell is that this is simply checking to make sure that the angular factor is not a null pointer before continuing.

But m_angularFactor is btVector3 (in previous Bullet versions it was btSalar) and not pointer. If I properly understand angular factor purpose, maybe code should be something like:

Code: Select all

if (m_angularFactor.len2() > 0)
 {
    do something with body angular vel
}

Or I'm wrong?

[Jasonrun]

I suppose it just depends on the purpose of the check. If it's to save some computation then you are probably correct. If it's just to protect against bad data then m_angularFactor.length2()==0 is still valid data. I'm not sure how it might get set to null though, but maybe it was a concern at some point?