Bullet physics btRaycastVehicle + Cocos3D

My long term goal is to make some form of truck game.  I'm not 100% sure what the game objectives will be, but I do know that it will be in 3D and will require simulated physics.


As a little example of what I have accomplished so far(very basic) I have recorded the following video.

Now that I have got Cocos3D up and running with Bullet physics, I thought the first step would be to try and implement some of their examples.


This is where the ray cast vehicle came into play.

I have had to make some alterations to the btRaycastVehicle library to get it up and running.


I could not for the live of me get the steering rotation to render correctly within cocos3d.


So I stripped out the steering rotation from within bullet and now do this within my cocos3d app.


In


void btRaycastVehicle::updateWheelTransform( int wheelIndex , bool interpolatedTransform)


I have changed


wheel.m_worldTransform.setBasis(steeringMat * rotatingMat * basis2);


to

wheel.m_worldTransform.setBasis(steeringMat   * btMatrix3x3(m_chassisBody->getOrientation()));

Now within my cocos3d application I have a wheel node that renders the position and steering angle of the physics wheel and a child node that is actually the tyre.


I rotate the tyre node manually from my wheels rotation information


tyre.rotation = cc3v(-1 * (wheelInf.m_rotation * (180/3.142)),0,0);

The above converts the m_rotation in radians to the degrees required for cocos3d rotation.

Unfortunatly after all this it has shown to me that a raycast vehicle doesn't really work for trucks moving over terrain, so I will now need to construct one from scratch! Lets see what happens....

Duncan.