three.js/examples/js/postprocessing/DotScreenPass.js

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

THREE.DotScreenPass = function ( center, angle, scale ) {

	if ( THREE.DotScreenShader === undefined )
		console.error( "THREE.DotScreenPass relies on THREE.DotScreenShader" );

	var shader = THREE.DotScreenShader;

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

	if ( center !== undefined ) this.uniforms[ "center" ].value.copy( center );
	if ( angle !== undefined ) this.uniforms[ "angle" ].value = angle;
	if ( scale !== undefined ) this.uniforms[ "scale" ].value = scale;

	this.material = new THREE.ShaderMaterial( {

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

	} );

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


	this.camera = new THREE.OrthographicCamera( - 1, 1, 1, - 1, 0, 1 );
	this.scene  = new THREE.Scene();

	this.quad = new THREE.Mesh( new THREE.PlaneBufferGeometry( 2, 2 ), null );
	this.scene.add( this.quad );

};

THREE.DotScreenPass.prototype = {

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

		this.uniforms[ "tDiffuse" ].value = readBuffer;
		this.uniforms[ "tSize" ].value.set( readBuffer.width, readBuffer.height );

		this.quad.material = this.material;
		this.quad.material.stencilTest = maskActive;

		if ( this.renderToScreen ) {

			renderer.render( this.scene, this.camera );

		} else {

			renderer.render( this.scene, this.camera, writeBuffer, false );

		}

	}

};