Graphics.Blit
static function Blit(source: Texture, dest: RenderTexture): void;
static void Blit(Texture source, RenderTexture dest);
static def Blit(source as Texture, dest as RenderTexture) as void
static function Blit(source: Texture, dest: RenderTexture, mat: Material, pass: int = -1): void;
static void Blit(Texture source, RenderTexture dest, Material mat, int pass = -1);
static def Blit(source as Texture, dest as RenderTexture, mat as Material, pass as int = -1) as void
static function Blit(source: Texture, mat: Material, pass: int = -1): void;
static void Blit(Texture source, Material mat, int pass = -1);
static def Blit(source as Texture, mat as Material, pass as int = -1) as void
Parameters

source Source texture.
dest Destination RenderTexture, or null to blit directly to screen.
mat Material to use for copying. Material's shader could do some post-processing effect, for example.
pass If -1 (default), draws all passes in the material. Otherwise, draws given pass only.
Description

Copies source texture into destination render texture.

This is mostly used for implementing image effects, and requires Unity Pro.

Blit sets dest to be active render texture, sets source as _MainTex property on the material, and draws a full-screen quad.

See Also: Graphics.BlitMultiTap, image effects.
	// Copies aTexture to rTex and displays it in all cameras.
	var aTexture : Texture;
	var rTex : RenderTexture;
	function Start() {
		if(!aTexture || !rTex)
			Debug.LogError("A texture or a render texture are missing, assign them.");
	}
	function Update () {
		Graphics.Blit (aTexture, rTex);
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    public Texture aTexture;
    public RenderTexture rTex;
    void Start() {
        if (!aTexture || !rTex)
            Debug.LogError("A texture or a render texture are missing, assign them.");
        
    }
    void Update() {
        Graphics.Blit(aTexture, rTex);
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	public aTexture as Texture

	public rTex as RenderTexture

	def Start() as void:
		if (not aTexture) or (not rTex):
			Debug.LogError('A texture or a render texture are missing, assign them.')

	def Update() as void:
		Graphics.Blit(aTexture, rTex)