I have a tank model consisting of multiple parts, a body, a turret and the barrel of the gun. The turret is offset from the body origin and can rotate around the Y axis(up). The barrel is connected to the turret and can rotate around the X axis of its connecting point to the turret.
I was wondering, given a target in 3d space and the position of the tank, how to calculate the correct rotations to give to the parts in order for the barrel to align itself to fire at the target.
The position of the tank cannot change, only the rotations given to the turret and the barrel. I would know how to solve this if the barrel is aligned with the z axis of the turret but I am having difficulty solving this problem if parts are offset from each other. Eventually I want to expand this so that multiple joined parts can get the end part (firing point) facing a target. I am using XNA C#.
EDIT:
Below is an example of what I mean, a turret connected to the body at the blue point. The barrel is connected to the turret at the red point:
