GL.Viewport 视口

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
	public Material mat;
	private bool stretch = false;
	void Update() {
		if (Input.GetKeyDown(KeyCode.Space))
			if (stretch)
				stretch = false;
			else
				stretch = true;

	}
	void OnPostRender() {
		if (!mat) {
			Debug.LogError("Please Assign a material on the inspector");
			return;
		}
		GL.PushMatrix();
		mat.SetPass(0);
		GL.LoadPixelMatrix();
		if (stretch)
			GL.Viewport(new Rect(0, 0, Screen.width, Screen.height));
		else
			GL.Viewport(new Rect(0, 0, Screen.width / 2, Screen.height));
		GL.Color(Color.red);
		GL.Begin(GL.QUADS);
		GL.Vertex3(0, 0, 0);
		GL.Vertex3(0, Screen.height, 0);
		GL.Vertex3(Screen.width, Screen.height, 0);
		GL.Vertex3(Screen.width, 0, 0);
		GL.Color(Color.yellow);
		GL.End();
		GL.Begin(GL.TRIANGLES);
		GL.Vertex3(Screen.width / 2, Screen.height / 4, 1);
		GL.Vertex3(Screen.width / 4, Screen.height / 2, 1);
		GL.Vertex3(Screen.width - Screen.width / 4, Screen.height / 2, 1);
		GL.End();
		GL.PopMatrix();
	}
}

// Draw a red Quad that covers all the view port, and the when space is pressed
// the viewport gets expanded to the whole screen and stretch the contents inside
//画一个红色的四边形，覆盖所有的视口，当按下空格键视口将扩展到整个屏幕并且拉伸里面的内容
var mat : Material;
private var stretch : boolean = false;

function Update() {
	if(Input.GetKeyDown(KeyCode.Space)) {
		if(stretch) {
			stretch = false;
		} else {
			stretch = true;
		}
	}
}

function OnPostRender() {
	if (!mat) {
		Debug.LogError("Please Assign a material on the inspector");
		return;
	}
	GL.PushMatrix();
	mat.SetPass(0);
	GL.LoadPixelMatrix();
	if(stretch) {
		GL.Viewport(Rect(0,0,Screen.width,Screen.height));
	} else {
		GL.Viewport(Rect(0,0,Screen.width/2,Screen.height));
	}
	GL.Color(Color.red);
	GL.Begin(GL.QUADS);
	GL.Vertex3(0,0,0);
	GL.Vertex3(0,Screen.height,0);
	GL.Vertex3(Screen.width,Screen.height,0);
	GL.Vertex3(Screen.width,0,0);
	GL.Color(Color.yellow);
	GL.End();
	GL.Begin(GL.TRIANGLES);
	GL.Vertex3(Screen.width/2,Screen.height/4,1);
	GL.Vertex3(Screen.width/4,Screen.height/2,1);
	GL.Vertex3(Screen.width - Screen.width/4,Screen.height/2,1);
	GL.End();
	GL.PopMatrix();
}