TestPhysicsHingeJoint flicker at start

Troubleshooting physics
1

I wanted to use some pivot joints in my game, so I had a look at the test example of the pendulum http://code.google.com/p/jmonkeyengine/source/browse/trunk/engine/src/test/jme3test/bullet/TestPhysicsHingeJoint.java. I never really noticed the flicker until I used it in my game and had to translate it, then it was very noticeable. But you can even see it in the test itself where is starts at 1 position, and then immediately moves to another, if only for a brief millisecond.



Took me about 3 tries to get this first pic, I got very lucky xD, could’ve taken a lot more, anyways: heres like 0.01 seconds into loading.

FlpK1.png1440×900
http://imgur.com/FlpK1.png



heres 0.02 seconds (what it should look like)

uzZLI.png1440×900
http://imgur.com/uzZLI.png



Just wondering if anyone else can see this using the test, or is it just me?

2

Hi, sorry for bumping (hope i gave it enough time). I just want to know if anyone else experiences the same issue with the test. So that i can look to commit a fix, or look for an alternative solution, but I don’t want to try and fix something that isn’t broken, so if anyone could try the test and tell me if they get the same behaviour as this, it would be appreciated, thx.

3

This is a lot easier to reproduce if you reduce the accuracy.

Invert y-axis value on line 98 or 102 to fix this, you could also add a y value on line 93 I think.



The problem has to do with the pivot orientation on the hingejoint and the initial position of the hammer and holder.