elchtest mod :)

[sebiastisch]

I have some updates:

We were able to integrate a real collision test and set the contact properties. looks pretty good, but we still have a lot of problems with it:

1. Bullet gives several collision points+normals of the cylinder and the ground. currently i am averaging them all out. but using the normals doesn't work.
i am calculating a fake normal pointing from the hit point to the center of the wheel.

2. force feedback is totally messed. it always drags the wheel to the left and the values are extremely noncontinuous.

3. there is not much grip. although the wheels do not collide with the surface (i mean not dynamically in bullet), they seem get a lot of traction.

4. driving is totally different. i have to give you a video with this!

5. when letting the car fall down on the surface, there is hopping/jumping around. I am not sure whether that is caused by the suspension or the contact calculation.

So, another update for the update:
I can fix that force feedback issue and pretty everything but the hopping issue by doing a simple hack:
The contact normal is set to 0,0,1 and the collision point set to the center of the wheel.
There seems to be a problem with the setContactProperties, as the behavior reminded me to the behavior of the elchtest mod.