MouseLook.cs

// original by asteins
// adapted by @torahhorse
// http://wiki.unity3d.com/index.php/SmoothMouseLook

// Instructions:
// There should be one MouseLook script on the Player itself, and another on the camera
// player's MouseLook should use MouseX, camera's MouseLook should use MouseY

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class MouseLook : MonoBehaviour
{

	public enum RotationAxes { MouseX = 1, MouseY = 2 }
	public RotationAxes axes = RotationAxes.MouseX;
	public bool invertY = false;

	public float sensitivityX = 10F;
	public float sensitivityY = 9F;

	public float minimumX = -360F;
	public float maximumX = 360F;

	public float minimumY = -85F;
	public float maximumY = 85F;

	float rotationX = 0F;
	float rotationY = 0F;

	private List<float> rotArrayX = new List<float>();
	float rotAverageX = 0F;

	private List<float> rotArrayY = new List<float>();
	float rotAverageY = 0F;

	public float framesOfSmoothing = 5;

	Quaternion originalRotation;

	void Start ()
	{
		if (rigidbody)
		{
			rigidbody.freezeRotation = true;
		}

		originalRotation = transform.localRotation;
	}

	void Update ()
	{
		if (axes == RotationAxes.MouseX)
		{
			rotAverageX = 0f;

			rotationX += Input.GetAxis("Mouse X") * sensitivityX * Time.timeScale;

			rotArrayX.Add(rotationX);

			if (rotArrayX.Count >= framesOfSmoothing)
			{
				rotArrayX.RemoveAt(0);
			}
			for(int i = 0; i < rotArrayX.Count; i++)
			{
				rotAverageX += rotArrayX[i];
			}
			rotAverageX /= rotArrayX.Count;
			rotAverageX = ClampAngle(rotAverageX, minimumX, maximumX);

			Quaternion xQuaternion = Quaternion.AngleAxis (rotAverageX, Vector3.up);
			transform.localRotation = originalRotation * xQuaternion;
		}
		else
		{
			rotAverageY = 0f;

 			float invertFlag = 1f;
 			if( invertY )
 			{
 				invertFlag = -1f;
 			}
			rotationY += Input.GetAxis("Mouse Y") * sensitivityY * invertFlag * Time.timeScale;

			rotationY = Mathf.Clamp(rotationY, minimumY, maximumY);

			rotArrayY.Add(rotationY);

			if (rotArrayY.Count >= framesOfSmoothing)
			{
				rotArrayY.RemoveAt(0);
			}
			for(int j = 0; j < rotArrayY.Count; j++)
			{
				rotAverageY += rotArrayY[j];
			}
			rotAverageY /= rotArrayY.Count;

			Quaternion yQuaternion = Quaternion.AngleAxis (rotAverageY, Vector3.left);
			transform.localRotation = originalRotation * yQuaternion;
		}
	}

	public void SetSensitivity(float s)
	{
		sensitivityX = s;
		sensitivityY = s;
	}

	public static float ClampAngle (float angle, float min, float max)
	{
		angle = angle % 360;
		if ((angle >= -360F) && (angle <= 360F)) {
			if (angle < -360F) {
				angle += 360F;
			}
			if (angle > 360F) {
				angle -= 360F;
			}
		}
		return Mathf.Clamp (angle, min, max);
	}
}