LineRenderer实现一个画线组件

 using System;
 using UnityEngine;

 class UILine
 {
     GameObject targetObj;
     LineRenderer lineRenderer;      //LineRenderer渲染出的线段的两个端点是3D世界中的点
     int index = ;
     int poinCount = ;  //线段的端点数
     Vector3 position;

     public void Start(GameObject go, Color beginColor, Color endColor, float begineWidth, float endWidth)
     {
         targetObj = go;
         if (null != targetObj)
         {
             targetObj.SetActive(true);
             lineRenderer = targetObj.GetComponent<LineRenderer>();

             if (null == lineRenderer)
                 lineRenderer = targetObj.AddComponent<LineRenderer>();
         }

         if (null != lineRenderer)
         {
             //颜色
             lineRenderer.startColor = beginColor;
             lineRenderer.endColor = endColor;

             //宽度
             lineRenderer.startWidth = begineWidth;
             lineRenderer.endWidth = endWidth;
         }

         index = poinCount = ;
     }

     public void Update()
     {
         if (Input.GetMouseButton())
         {
             //屏幕坐标转换为世界坐标
             position = Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, 1.0f));
             //端点数+1
             poinCount++;
             //设置线段的端点数
             lineRenderer.positionCount = poinCount;

             //连续绘制线段
             while (index < poinCount)
             {
                 //两点确定一条直线，所以我们依次绘制点就可以形成线段了
                 lineRenderer.SetPosition(index, position);
                 index++;
             }
         }
     }

     public static UILine BeginLine(GameObject go, Color beginColor, Color endColor, float beginWidth, float endWidth)
     {
         UILine line = new UILine();
         line.Start(go, beginColor, endColor, beginWidth, endWidth);
         return line;
     }
 }