Unity C# - TorqueLookRotation2D

TorqueLookRotation2D.cs

using UnityEngine;
using System.Collections;
 
// @stefanhayden 2015
// based on http://wiki.unity3d.com/index.php/TorqueLookRotation
// set the object's rigidbody angular drag to a high value, like 10 or 50
 
public class TorqueLookRotation : MonoBehaviour {
 
	public Transform target;
	public float force = 0.1f;
 
	void FixedUpdate () {
 
		Vector3 targetDelta = target.position - transform.position;
 
		//get the angle between transform.forward and target delta
		float angleDiff = Vector3.Angle(transform.up, targetDelta);
 
		// get its cross product, which is the axis of rotation to
		// get from one vector to the other
		Vector3 cross = Vector3.Cross(transform.up, targetDelta);
 
		// apply torque along that axis according to the magnitude of the angle.
		rigidbody.AddTorque(cross.z * angleDiff * force);
		
		
	}
}