Unity实现画线条功能

using UnityEngine;
using System.Collections;
 
public class NewBehaviourScript : MonoBehaviour {
 
 private GameObject clone;
 private LineRenderer line;
 int i;
 //带有LineRender物体
 public GameObject target;
 void Start () {
 
 }
 
 // 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)));
 
 
 }
 
 }
}