Unity使用LineRender断笔写字

using UnityEngine;using System.Collections;using System.Collections.Generic; public class DrawLine : MonoBehaviour{  //线段预制  [Tooltip("Line renderer used for the line drawing.")]  public LineRenderer linePrefab;   //线段相关保存和下标  private List<GameObject> linesDrawn = new List<GameObject>();  private LineRenderer currentLine;  private int lineVertexIndex = 2;   void Update()  {    //删除最近一笔    if (Input.GetKeyDown(KeyCode.U))    {      // U-key means Undo      DeleteLastLine();    }     if (currentLine == null &&      Input.GetMouseButton(0))    {      // 鼠标按下，开始画线      currentLine = Instantiate(linePrefab).GetComponent<LineRenderer>();      currentLine.name = "Line" + linesDrawn.Count;      currentLine.transform.parent = transform;       Vector3 cursorPos = Input.mousePosition;      cursorPos.z = 0f;       //将鼠标按下的屏幕坐标转换成世界坐标      Vector3 cursorSpacePos = Camera.main.ScreenToWorldPoint(cursorPos);      cursorSpacePos.z = 0f;      currentLine.SetPosition(0, cursorSpacePos);      currentLine.SetPosition(1, cursorSpacePos);       lineVertexIndex = 2;      linesDrawn.Add(currentLine.gameObject);       StartCoroutine(DrawLines());    }     if (currentLine != null &&      Input.GetMouseButtonUp(0))    {      // 鼠标左键抬起结束当前笔画      currentLine = null;    }  }   //撤销最后一笔  public void DeleteLastLine()  {    if (linesDrawn.Count > 0)    {      GameObject goLastLine = linesDrawn[linesDrawn.Count - 1];      linesDrawn.RemoveAt(linesDrawn.Count - 1);      Destroy(goLastLine);    }  }   //持续画线  IEnumerator DrawLines()  {    while (Input.GetMouseButton(0))    {      yield return new WaitForEndOfFrame();       if (currentLine != null)      {        lineVertexIndex++;        currentLine.SetVertexCount(lineVertexIndex);         Vector3 cursorPos = Input.mousePosition;        cursorPos.z = 0f;         Vector3 cursorSpacePos = Camera.main.ScreenToWorldPoint(cursorPos);        cursorSpacePos.z = 0f;        currentLine.SetPosition(lineVertexIndex - 1, cursorSpacePos);      }    }  }}