gistfile1.cs

using UnityEngine;
using System.Collections;

public class MouseOrbit : MonoBehaviour {


        public Transform target;
        public float distance = 10.0f;
 
        public float xSpeed = 250.0f;
        public float ySpeed = 120.0f;
 
        public float yMinLimit = -20;
        public float yMaxLimit = 80;
        public bool NeedCruise;
        public float CruiseSpeed = 0.5f;

    public float x = 0.0f;
    public float y = 0.0f;
 
        void Start () 
        {
            var angles = transform.eulerAngles;
            x = angles.y;
            y = angles.x;
 
            // Make the rigid body not change rotation
            if (rigidbody) 
                rigidbody.freezeRotation = true;
        }
 
        void Update ()
        {
            Debug.Log("(Mouse X, Mouse Y)=(" + Input.GetAxis("Mouse X") + ", " + Input.GetAxis("Mouse Y") + ")");
            if (target)
            {
                
                x += Input.GetAxis("Mouse X") * xSpeed * Time.deltaTime;
                y -= Input.GetAxis("Mouse Y") * ySpeed * Time.deltaTime;

               

                y = ClampAngle360(y, yMinLimit, yMaxLimit);
                if (NeedCruise)
                    x += CruiseSpeed;
                x = ClampAngle180(x);

                
 
                transform.rotation = Quaternion.Euler(y, x, 0);
                transform.position = (Quaternion.Euler(y, x, 0)) * new Vector3(0.0f, 0.0f, -distance) + target.position;
            }
        }

    float ClampAngle180(float angle)
    {
        float r = angle;
        if (angle > 180f || angle < -180f)
        {
            int d = (int) (angle/180);
            r = angle - (d +1f)*180;
        }
        return r;
    }
 
        static float ClampAngle360(float angle, float min, float max) 
        {
            if (angle < -360)
            {
                angle += 360;
            }
            if (angle > 360)
            {
                angle -= 360;
            }
            return Mathf.Clamp(angle, min, max);
        }
}