Jitter Physics not working correctly. Going through objects and getting pushed back when touching walls

Question

I am trying to use the Jitter physics engine, however, I can't get it to work correctly. For example, when I touch the side of a cube, it pushes me far back in the opposite direction. While I am flying back, if I hold the opposite directional key, I keep getting slower until I come to full stop.

Other times, I go right through the floor. I followed this tutorial.

I gave my floors BoxShapes and a RigidBody. I set them to static so the rigidbodies won't move. I did the same in my Player class but didn't set it to static.

How do I make it work correctly? If someone knows a better tutorial or physics engine I can use in C# with MonoGame/XNA, please let me know.

Answer 1

It's been a while since I used Jitter, but here's my two cents:

• The push-back happens because a force is applied to your character in order to avoid penetration with the wall. Setting World.ContactSettings.BiasFactor to a lower value should reduce the force used, but may also cause slight penetration or other issues.

• I had a similar problem with errant collision, which was caused by a Jitter bug. If you are using the 0.1.7.0 version (the last download, from Oct 2011), you are affected by it. The first line in JVector.TransposedTransform should be

  float num0 = ((position.X * matrix.M11) + (position.Y * matrix.M12)) + (position.Z * matrix.M13);

  The incorrect version has M31 instead of M13.

• I don't know about current .Net physics engines, but Jitter certainly seems long since abandoned and somewhat incomplete.

Answer 2

Make sure your faces are oriented the right way; use IDebugDrawer to verify this.