three.js/examples/js/postprocessing/HalftonePass.js

( function () {

	/**
 * RGB Halftone pass for three.js effects composer. Requires THREE.HalftoneShader.
 */

	var HalftonePass = function ( width, height, params ) {

		THREE.Pass.call( this );

		if ( THREE.HalftoneShader === undefined ) {

			console.error( 'THREE.HalftonePass requires THREE.HalftoneShader' );

		}

		this.uniforms = THREE.UniformsUtils.clone( THREE.HalftoneShader.uniforms );
		this.material = new THREE.ShaderMaterial( {
			uniforms: this.uniforms,
			fragmentShader: THREE.HalftoneShader.fragmentShader,
			vertexShader: THREE.HalftoneShader.vertexShader
		} ); // set params

		this.uniforms.width.value = width;
		this.uniforms.height.value = height;

		for ( var key in params ) {

			if ( params.hasOwnProperty( key ) && this.uniforms.hasOwnProperty( key ) ) {

				this.uniforms[ key ].value = params[ key ];

			}

		}

		this.fsQuad = new THREE.Pass.FullScreenQuad( this.material );

	};

	HalftonePass.prototype = Object.assign( Object.create( THREE.Pass.prototype ), {
		constructor: HalftonePass,
		render: function ( renderer, writeBuffer, readBuffer
			/*, deltaTime, maskActive*/
		) {

			this.material.uniforms[ 'tDiffuse' ].value = readBuffer.texture;

			if ( this.renderToScreen ) {

				renderer.setRenderTarget( null );
				this.fsQuad.render( renderer );

			} else {

				renderer.setRenderTarget( writeBuffer );
				if ( this.clear ) renderer.clear();
				this.fsQuad.render( renderer );

			}

		},
		setSize: function ( width, height ) {

			this.uniforms.width.value = width;
			this.uniforms.height.value = height;

		}
	} );

	THREE.HalftonePass = HalftonePass;

} )();