three.js/examples/js/postprocessing/GlitchPass.js

THREE.GlitchPass = function ( dt_size ) {

	THREE.Pass.call( this );

	if ( THREE.DigitalGlitch === undefined ) console.error( 'THREE.GlitchPass relies on THREE.DigitalGlitch' );

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

	if ( dt_size == undefined ) dt_size = 64;


	this.uniforms[ 'tDisp' ].value = this.generateHeightmap( dt_size );


	this.material = new THREE.ShaderMaterial( {
		uniforms: this.uniforms,
		vertexShader: shader.vertexShader,
		fragmentShader: shader.fragmentShader
	} );

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

	this.goWild = false;
	this.curF = 0;
	this.generateTrigger();

};

THREE.GlitchPass.prototype = Object.assign( Object.create( THREE.Pass.prototype ), {

	constructor: THREE.GlitchPass,

	render: function ( renderer, writeBuffer, readBuffer /*, deltaTime, maskActive */ ) {

		this.uniforms[ 'tDiffuse' ].value = readBuffer.texture;
		this.uniforms[ 'seed' ].value = Math.random();//default seeding
		this.uniforms[ 'byp' ].value = 0;

		if ( this.curF % this.randX == 0 || this.goWild == true ) {

			this.uniforms[ 'amount' ].value = Math.random() / 30;
			this.uniforms[ 'angle' ].value = THREE.MathUtils.randFloat( - Math.PI, Math.PI );
			this.uniforms[ 'seed_x' ].value = THREE.MathUtils.randFloat( - 1, 1 );
			this.uniforms[ 'seed_y' ].value = THREE.MathUtils.randFloat( - 1, 1 );
			this.uniforms[ 'distortion_x' ].value = THREE.MathUtils.randFloat( 0, 1 );
			this.uniforms[ 'distortion_y' ].value = THREE.MathUtils.randFloat( 0, 1 );
			this.curF = 0;
			this.generateTrigger();

		} else if ( this.curF % this.randX < this.randX / 5 ) {

			this.uniforms[ 'amount' ].value = Math.random() / 90;
			this.uniforms[ 'angle' ].value = THREE.MathUtils.randFloat( - Math.PI, Math.PI );
			this.uniforms[ 'distortion_x' ].value = THREE.MathUtils.randFloat( 0, 1 );
			this.uniforms[ 'distortion_y' ].value = THREE.MathUtils.randFloat( 0, 1 );
			this.uniforms[ 'seed_x' ].value = THREE.MathUtils.randFloat( - 0.3, 0.3 );
			this.uniforms[ 'seed_y' ].value = THREE.MathUtils.randFloat( - 0.3, 0.3 );

		} else if ( this.goWild == false ) {

			this.uniforms[ 'byp' ].value = 1;

		}

		this.curF ++;

		if ( this.renderToScreen ) {

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

		} else {

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

		}

	},

	generateTrigger: function () {

		this.randX = THREE.MathUtils.randInt( 120, 240 );

	},

	generateHeightmap: function ( dt_size ) {

		var data_arr = new Float32Array( dt_size * dt_size * 3 );
		var length = dt_size * dt_size;

		for ( var i = 0; i < length; i ++ ) {

			var val = THREE.MathUtils.randFloat( 0, 1 );
			data_arr[ i * 3 + 0 ] = val;
			data_arr[ i * 3 + 1 ] = val;
			data_arr[ i * 3 + 2 ] = val;

		}

		return new THREE.DataTexture( data_arr, dt_size, dt_size, THREE.RGBFormat, THREE.FloatType );

	}

} );