Unity 屏幕绘制

/**
 * ==========================================
 * FileName： TestDrawLine.cs
 * Author：   #Author#
 * CreatTime：#CreateTime#
 * ==========================================
 */

using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Xml.Serialization;
using UnityEngine;

//注意脚本需要挂载到摄像机上面
public class TestDrawLine : MonoBehaviour
{
    Vector3 curPos;
    List<List<Vector3>> lineData = new List<List<Vector3>>();
    List<Vector3> posList = new List<Vector3>();
    int interval;

    //public Transform cube;

    public Material lineMaterial;

    void CreateLineMaterial()
    {
        if (!lineMaterial)
        {
            Shader shader = Shader.Find("Unlit/ColorShader");
            //Shader shader = Shader.Find("Hidden/Internal-Colored");
            lineMaterial = new Material(shader);
            //lineMaterial.hideFlags = HideFlags.HideAndDontSave;
            ////设置参数
            //lineMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
            //lineMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
            ////设置参数
            //lineMaterial.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
            ////设置参数
            //lineMaterial.SetInt("_ZWrite", 0);
        }
    }

    private void OnPostRender()
    {
        DrawLine();
    }

    void OnGUI()
    {
        Event e = Event.current;

        if (e != null)
        {
            if (e.type == EventType.MouseDown)
            {
                
            }
            if (e.type == EventType.MouseDrag)
            {

                if (Vector3.Distance(curPos, Input.mousePosition) > interval)
                {
                    curPos = Input.mousePosition;
                    Vector3 end = new Vector3(curPos.x / Screen.width, curPos.y / Screen.height, 0);
                    posList.Add(end);
                }
            }
            if (e.type == EventType.MouseUp)
            {
                List<Vector3> l = Clone<List<Vector3>>(posList);
                if (l.Count > 0)
                {
                    lineData.Add(l);
                }

                posList.Clear();
                curPos = Vector3.zero;
            }
        }
    }

    void DrawLine()
    {
        GL.PushMatrix();
        GL.LoadOrtho();

        if (lineMaterial != null)
        {
            lineMaterial.SetPass(0);
        }
        GL.Begin(GL.LINES);
        GL.Color(Color.red);

        for (int j = 0; j < lineData.Count; j++) {
            List<Vector3> line = lineData[j];

            for (int i = 0; i < line.Count - 1; I++)
            {
                Vector3 pos = line[I];
                GL.Vertex3(pos.x, pos.y, pos.z);
                GL.Vertex3(line[i + 1].x, line[i + 1].y, line[i + 1].z);
            }
        }

        for (int i = 0; i < posList.Count - 1; I++)
        {
            Vector3 pos = posList[I];
            GL.Vertex3(pos.x, pos.y, pos.z);
            GL.Vertex3(posList[i + 1].x, posList[i + 1].y, posList[i + 1].z);
        }

        GL.End();
        GL.PopMatrix();
    }

    public void WithDraw() {
        if (lineData.Count > 0) {
            lineData.RemoveAt(lineData.Count - 1);
        }
    }

    public static T Clone<T>(T RealObject)
    {
        using (System.IO.Stream stream = new MemoryStream())
        {
            XmlSerializer serializer = new XmlSerializer(typeof(T));
            serializer.Serialize(stream, RealObject);
            stream.Seek(0, SeekOrigin.Begin);
            return (T)serializer.Deserialize(stream);
        }
    }
}