Unity3D如何自定义公告牌

using UnityEngine;
/* * 自定义公告牌，跟随镜头旋转永远平行面向屏幕，跟随镜头缩放缩放大小不变 */public class Billboard : MonoBehaviour {     Camera camera;//主镜头
    private float _fieldOfView;//初始fieldOfView
    void Start () {        camera = Camera.main;                _fieldOfView = camera.fieldOfView;    }        void Update ()    {        //跟随镜头旋转，直接把主镜头的旋转值赋值给公告牌即可        transform.rotation = camera.transform.rotation;                //跟随镜头缩放（缩放镜头设置的是镜头的fieldOfView值）        float fieldOfView = camera.fieldOfView;        transform.localScale = new Vector3(fieldOfView/_fieldOfView,fieldOfView/_fieldOfView,fieldOfView/_fieldOfView);    }
}

using UnityEngine;
/* * 自定义公告牌，跟随镜头旋转永远平行面向屏幕，跟随镜头缩放缩放大小不变 */ public class Billboard : MonoBehaviour {     Camera camera;//主镜头
    private float _distance;//初始距离
    void Start () {        camera = Camera.main;                _distance = Vector3.Distance(camera.transform.position, transform.position);    }        void Update ()    {        //跟随镜头旋转，直接把主镜头的旋转值赋值给公告牌即可        transform.rotation = camera.transform.rotation;
        //跟随镜头缩放（缩放镜头设置的镜头的位置），根据公告牌到主镜头的距离来做等距离缩放即可        float distance = Vector3.Distance(camera.transform.position, transform.position);//不断变化的距离        var scale = distance/_distance * 0.1F;        transform.localScale = new Vector3(scale,scale,scale);    } }