examples/webgl_postprocessing_procedural.html

<!DOCTYPE html>
<html lang="en">
	<head>
		<title>three.js webgl - postprocessing procedural effects</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
		<link type="text/css" rel="stylesheet" href="main.css">
	</head>
	<body>
		<div id="info">
			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - Procedural Effects Example by <a href="https://clara.io" target="_blank" rel="noopener">Ben Houston</a><br/><br/>
		</div>

		<script id="procedural-vert" type="x-shader/x-vertex">
			varying vec2 vUv;

			void main() {
				vUv = uv;
				gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
			}
		</script>
		<script id="noiseRandom1D-frag" type="x-shader/x-fragment">
			#include <common>

			varying vec2 vUv;

			void main() {
				gl_FragColor.xyz = vec3( rand( vUv ) );
				gl_FragColor.w = 1.0;
			}
		</script>
		<script id="noiseRandom2D-frag" type="x-shader/x-fragment">
			#include <common>

			varying vec2 vUv;

			void main() {
				vec2 rand2 = vec2( rand( vUv ), rand( vUv + vec2( 0.4, 0.6 ) ) );
				gl_FragColor.xyz = mix( mix( vec3( 1.0, 1.0, 1.0 ), vec3( 0.0, 0.0, 1.0 ), rand2.x ), vec3( 0.0 ), rand2.y );
				gl_FragColor.w = 1.0;
			}
		</script>
		<script id="noiseRandom3D-frag" type="x-shader/x-fragment">
			#include <common>

			varying vec2 vUv;

			void main() {
				vec3 rand3 = vec3( rand( vUv ), rand( vUv + vec2( 0.4, 0.6 ) ), rand( vUv + vec2( 0.6, 0.4 ) ) );
				gl_FragColor.xyz = rand3;
				gl_FragColor.w = 1.0;
			}
		</script>

		<div id="container"></div>

		<!-- Import maps polyfill -->
		<!-- Remove this when import maps will be widely supported -->
		<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.module.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';

			import Stats from 'three/addons/libs/stats.module.js';
			import { GUI } from 'three/addons/libs/lil-gui.module.min.js';

			let postCamera, postScene, renderer;
			let postMaterial, noiseRandom1DMaterial, noiseRandom2DMaterial, noiseRandom3DMaterial, postQuad;
			let stats;

			const params = { procedure: 'noiseRandom3D' };

			init();
			animate();
			initGui();

			// Init gui
			function initGui() {

				const gui = new GUI();
				gui.add( params, 'procedure', [ 'noiseRandom1D', 'noiseRandom2D', 'noiseRandom3D' ] );

			}

			function init() {

				const container = document.getElementById( 'container' );

				renderer = new THREE.WebGLRenderer();
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				document.body.appendChild( renderer.domElement );

				stats = new Stats();
				container.appendChild( stats.dom );

				// Setup post processing stage
				postCamera = new THREE.OrthographicCamera( - 1, 1, 1, - 1, 0, 1 );
				noiseRandom1DMaterial = new THREE.ShaderMaterial( {
					vertexShader: document.querySelector( '#procedural-vert' ).textContent.trim(),
					fragmentShader: document.querySelector( '#noiseRandom1D-frag' ).textContent.trim()
				} );
				noiseRandom2DMaterial = new THREE.ShaderMaterial( {
					vertexShader: document.querySelector( '#procedural-vert' ).textContent.trim(),
					fragmentShader: document.querySelector( '#noiseRandom2D-frag' ).textContent.trim()
				} );
				noiseRandom3DMaterial = new THREE.ShaderMaterial( {
					vertexShader: document.querySelector( '#procedural-vert' ).textContent.trim(),
					fragmentShader: document.querySelector( '#noiseRandom3D-frag' ).textContent.trim()
				} );
				postMaterial = noiseRandom3DMaterial;
				const postPlane = new THREE.PlaneGeometry( 2, 2 );
				postQuad = new THREE.Mesh( postPlane, postMaterial );
				postScene = new THREE.Scene();
				postScene.add( postQuad );

				window.addEventListener( 'resize', onWindowResize );

			}

			function onWindowResize() {

				const width = window.innerWidth;
				const height = window.innerHeight;

				postCamera.aspect = width / height;
				postCamera.updateProjectionMatrix();

				renderer.setSize( width, height );

			}

			function animate() {

				requestAnimationFrame( animate );

				switch ( params.procedure ) {

					case 'noiseRandom1D': postMaterial = noiseRandom1DMaterial; break;
					case 'noiseRandom2D': postMaterial = noiseRandom2DMaterial; break;
					case 'noiseRandom3D': postMaterial = noiseRandom3DMaterial; break;

				}

				postQuad.material = postMaterial;

				// render post FX
				renderer.render( postScene, postCamera );

				stats.update();

			}

		</script>
	</body>
</html>