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

( function () {

	var 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();

	};

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

		}
	} );

	THREE.GlitchPass = GlitchPass;

} )();