unity gl 画线

using UnityEngine;
using System.Collections;

public class TGLLine : MonoBehaviour {

	private static Material mat;

	void Start () {
		CreateLineMaterial();
	}

	void Update () {

	}

	//画线框用的mat
	public static Material CreateLineMaterial(){

		mat = new Material("Shader \"Lines/Colored Blended\" {" +
		                       "SubShader { Pass { " +
		                       " Blend SrcAlpha OneMinusSrcAlpha " +
		                       " ZWrite Off Cull Off Fog { Mode Off } " +
		                       " BindChannels {" +
		                       " Bind \"vertex\", vertex Bind \"color\", color }" +
		                       "} } }");
		mat.hideFlags = HideFlags.HideAndDontSave;
		mat.shader.hideFlags = HideFlags.HideAndDontSave;

		//mat.SetPass(0);

		return mat;
	}

	void OnRenderObject() {
		ShowLine(Color.green);
	}

	void ShowLine(Color c,float offsety = 0.2f)
	{
		//设置当前的材质
		mat.SetPass( 0 );
		GL.Begin( GL.LINES );
		GL.Color(c);
		for(int i=0;i<3;i++){
			Vector3 p0;
			p0.x=0f;
			p0.z=0f;
			p0.y=0+offsety;
			GL.Vertex(p0);

			Vector3 p;
			p.x=9f;
			p.z=0f+i*2;
			p.y=offsety;
			GL.Vertex(p);
		}

		GL.End();
	}
}