Weld joint definition. You need to specify local anchor points where they are attached and the relative body angle. The position of the anchor points is important for computing the reaction torque.
Constructor.
The first attached body.
The second attached body.
Set this flag to true if the attached bodies should collide.
The local anchor point relative to body1's origin.
The local anchor point relative to body2's origin.
The body2 angle minus body1 angle in the reference state (radians).
The joint type is set automatically for concrete joint types.
Use this to attach application specific data to your joints.
Initialize the bodies, anchors, axis, and reference angle using the world anchor and world axis.