FixedJoint (and SliderJoint) don't seem to work when bodies are rotated with non-identity transform about reactphysics3d

[jrouwe]

What I forgot to mention is that the problem is in FixedJoint::solvePositionConstraint. If you comment out the entire block under:

// --------------- Rotation Constraints --------------- //

the jitter is gone (but obviously the body rotation will start to drift eventually).

[jrouwe]

Hello,

I created a fix for the bug and created a pull request for you:

#29

Derivation of the (hopefully) correct equations are in the source code.

Note that I only tested this on the FixedJoint (for both position correction techniques). But the code in SliderJoint is exactly the same.

[jrouwe]

I also hacked in some extra fixed bodies in the JointsScene (you probably don't want to integrate but nice for verifying that it works):

https://github.com/jrouwe/reactphysics3d/commit/6e5f067cdadd98c7a1f371dbb9a68cba05ce4f77

[DanielChappuis]

Thanks a lot for your work.

I will check your pull request on Monday or Tuesday when I have some time. When I was able to reproduce the issue 2 days ago I suspected that something was wrong with the way I compute the orientation difference between the bodies.

[DanielChappuis]

I have cherry-picked the commit that fixes the bug in your pull request and I have merged the following commit : 1855e1c into the master branch.

Thanks a lot for reporting and fixing this issue.