Unityカメラの手ぶれ効果

カメラのジグル効果のソースコードは次のとおりです.

using UnityEngine;
using System.Collections;
public class SC_shakeCamera : MonoBehaviour{    
    private float shakeTime = 0.0f;    
    private float fps = 20.0f;    
    private float frameTime = 0.0f;    
    private float shakeDelta = 0.005f;    
    public Camera cam; //= UICamera.currentCamera;   
    public bool isshakeCamera = false;    // Use this for initialization    
    void Start()    {      
        //  cam = UICamera.currentCamera;        
        shakeTime = 0.56f;        
        fps = 20.0f;       
        frameTime = 0.03f;        
        shakeDelta = 0.05f;       
    }    
    // Update is called once per frame    
    void Update()    {        
        if (isshakeCamera)        {            
            if (shakeTime > 0)            {              
                shakeTime -= Time.deltaTime;                
                if (shakeTime <= 0)                {                    
                    cam.rect = new Rect(0.0f, 0.0f, 10.0f, 10.0f);                   
                    isshakeCamera = false;                    
                    shakeTime = 0.56f;                    
                    fps = 20.0f;                    
                    frameTime = 0.03f;                    
                    shakeDelta = 0.05f;                }                
                else                {                    
                    frameTime += Time.deltaTime;                    
                    if (frameTime > 1.0 / fps)                    {                        
                        frameTime = 0;                        
                        cam.rect = new Rect(shakeDelta * (-1.0f + 2.0f * Random.value), shakeDelta * (-1.0f + 2.0f * Random.value), 1.0f, 1.0f);                   
                    }               
                }            
            }        
        }   
    }    
  
}