注意：用Debug画的线会存在穿透问题

没啥好解释的，直接看代码：

using UnityEngine;using System.Collections;using System.Collections.Generic; /*  * 找不到设置线宽的方法，目前的解决方法就是用画矩形代替画线来实现线的粗细  *//// 
/// 必须将此脚本放在摄影机上才能看到绘画内容,DebugDraw可以不用，但DebugDraw画的内容/// 只能在编辑模式下看得到。/// 
[RequireComponent(typeof(Camera))]public class DrawTrack: MonoBehaviour{    /// 
    /// 画笔的材质    /// 
    public Material Material;    /// 
    /// 绘画该目标的移动路径    /// 
    public Transform Target;    /// 
    /// 画笔平滑度    /// 
    public float Smooth = 1;    /// 
    /// 是否也在编辑器里绘画出线    /// 
    public bool DebugDraw = true;    /// 
    /// 存放移动路径的点的集合    /// 
    private List
     
       path;    /// 
      
    /// 目标的最后一个移动点    /// 
    private Vector3 lastPosition;    void Start()    {        if (Material == null)        {            Debug.LogError("请先赋予该脚本 Material !!");        }        if (Target == null)        {            Debug.LogError("请设置目标");        }        path = new List
      
       ();        lastPosition = Target.position;    }    void Update()    {        if (Vector3.Distance(Target.position, lastPosition) > Smooth)        {            path.Add(Target.position);            lastPosition = Target.position;        }    }        /// 
       
    /// GL绘图必须在这个函数中进行    /// 
    void OnPostRender()    {        GL.PushMatrix();        Material.SetPass(0);        // 若要绘制2D线段，则取消注释GL.LoadOrtho();        //GL.LoadOrtho();        GL.Begin(GL.LINES);        /*******在此处进行绘画*********/        DrawLines(path.ToArray());        GL.End();        GL.PopMatrix();    }    private void DrawLine(Vector3 start, Vector3 end)    {        GL.Vertex3(start.x, start.y, start.z);        GL.Vertex3(end.x, end.y, end.z);        if (DebugDraw)        {            Debug.DrawLine(start, end, Color.red, 1);        }    }    private void DrawLines(Vector3[] points)    {        if (points.Length == 0)        {            return;        }        for (int i = 0; i < points.Length - 1; ++i)        {            var start = points[i];            var end = points[i + 1];            GL.Vertex3(start.x, start.y, start.z);            GL.Vertex3(end.x, end.y, end.z);            if (DebugDraw)            {                Debug.DrawLine(start, end, Color.red, 1);            }        }    }    public void ClearLine()    {        path.Clear();    }            }