unity实现屏幕上写字效果

using System.Collections;using System.Collections.Generic;using UnityEngine;public class huaxian : MonoBehaviour {private GameObject clone;private LineRenderer line;int i;//带有LineRender物体public GameObject target;void Start(){  Debug.Log("请开始写字");} // Update is called once per frame  void Update(){  if (Input.GetMouseButtonDown(0))  {    //实例化对象     clone = (GameObject)Instantiate(target, target.transform.position, Quaternion.identity);    //获得该物体上的LineRender组件     line = clone.GetComponent<LineRenderer>();    //设置起始和结束的颜色     line.SetColors(Color.red, Color.blue);    //设置起始和结束的宽度      line.SetWidth(0.2f, 0.1f);    //计数      i = 0;  }   if (Input.GetMouseButton(0))  {    //每一帧检测，按下鼠标的时间越长，计数越多     i++;    //设置顶点数     line.SetVertexCount(i);    //设置顶点位置(顶点的索引，将鼠标点击的屏幕坐标转换为世界坐标)     line.SetPosition(i - 1, Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, 15)));  } } }