initialize method
Initialize the bodies, anchors, axis, and reference angle using the world anchor and world axis.
Implementation
void initialize(A bodyA, B bodyB, Vector2 anchor) {
this.bodyA = bodyA;
this.bodyB = bodyB;
localAnchorA.setFrom(bodyA.localPoint(anchor));
localAnchorB.setFrom(bodyB.localPoint(anchor));
}