GL.Viewport

Parameters

Description

Set the rendering viewport.

All rendering is constrained to be inside the passed pixelRect.
If the Viewport is modified, all the rendered content inside of it gets stretched.

	// 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
	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();
	}

using UnityEngine;
using System.Collections;

public class ExampleClass : 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();
    }
}