three.js/examples/js/postprocessing/TexturePass.js

/**
 * @author alteredq / http://alteredqualia.com/
 */

THREE.TexturePass = function ( texture, opacity ) {

	if ( THREE.BlitShader === undefined )
		console.error( "THREE.TexturePass relies on THREE.BlitShader" );

	var shader = THREE.BlitShader;

	this.uniforms = THREE.UniformsUtils.clone( shader.uniforms );

	this.uniforms[ "opacity" ].value = ( opacity !== undefined ) ? opacity : 1.0;
	this.uniforms[ "tDiffuse" ].value = texture;

	this.material = new THREE.ShaderMaterial( {

		uniforms: this.uniforms,
		vertexShader: shader.vertexShader,
		fragmentShader: shader.fragmentShader

	} );

	this.enabled = true;
	this.needsSwap = false;

};

THREE.TexturePass.prototype = {

	render: function ( renderer, writeBuffer, readBuffer, delta ) {

		THREE.EffectComposer.quad.material = this.material;

		renderer.render( THREE.EffectComposer.scene, THREE.EffectComposer.camera, readBuffer );

	}

};