缩放视野

//控制视野缩放的速率
    public float view_value;
 void Update(){
 //放大、缩小
        if (Input.GetKey(KeyCode.A))
        {
            this.gameObject.transform.Translate(new Vector3(0, 0, Time.deltaTime * view_value));
        }
        if (Input.GetKey(KeyCode.D))
        {
            this.gameObject.transform.Translate(new Vector3(0, 0, Time.deltaTime * -view_value));
        }
}