<script type="x-shader/x-vertex" id="vertexshader">

  varying vec2 vUv;

  void main() {

    vUv = uv;

    gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

  }

</script>

<script type="x-shader/x-fragment" id="fragmentshader">

  uniform sampler2D baseTexture;
  uniform sampler2D bloomTexture;

  varying vec2 vUv;

  void main() {

    gl_FragColor = ( texture2D( baseTexture, vUv ) + vec4( 1.0 ) * texture2D( bloomTexture, vUv ) );

  }

</script>

<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>

<script type="importmap">
  {
    "imports": {
      "three": "https://unpkg.com/three@0.131.3/build/three.module.js"
    }
  }
</script>

<script type="module">

  import * as THREE from 'three';

  import { OrbitControls } from 'https://unpkg.com/three@0.131.3/examples/jsm/controls/OrbitControls.js';
  import { EffectComposer } from 'https://unpkg.com/three@0.131.3/examples/jsm/postprocessing/EffectComposer.js';
  import { RenderPass } from 'https://unpkg.com/three@0.131.3/examples/jsm/postprocessing/RenderPass.js';
  import { ShaderPass } from 'https://unpkg.com/three@0.131.3/examples/jsm/postprocessing/ShaderPass.js';
  import { UnrealBloomPass } from 'https://unpkg.com/three@0.131.3/examples/jsm/postprocessing/UnrealBloomPass.js';

  const ENTIRE_SCENE = 0, BLOOM_SCENE = 1;
  let plane;

  const bloomLayer = new THREE.Layers();
  bloomLayer.set( BLOOM_SCENE );

  const params = {
    exposure: 1,
    bloomStrength: 5,
    bloomThreshold: 0,
    bloomRadius: 0,
    scene: 'Scene with Glow'
  };

  const darkMaterial = new THREE.MeshBasicMaterial( { color: 'black' } );
  const materials = {};

  const renderer = new THREE.WebGLRenderer( { antialias: true } );
  renderer.setPixelRatio( window.devicePixelRatio );
  renderer.setSize( window.innerWidth, window.innerHeight );
  renderer.toneMapping = THREE.ReinhardToneMapping;

  document.body.appendChild( renderer.domElement );

  const scene = new THREE.Scene();
  // scene.background = new THREE.Color('gray');
  const camera = new THREE.PerspectiveCamera( 40, window.innerWidth / window.innerHeight, 1, 200 );
  camera.position.set( 0, 0, 20 );
  camera.lookAt( 0, 0, 0 );

  const controls = new OrbitControls( camera, renderer.domElement );
  controls.maxPolarAngle = Math.PI * 0.5;
  controls.minDistance = 1;
  controls.maxDistance = 100;
  controls.addEventListener( 'change', render );

  scene.add( new THREE.AmbientLight( 0x404040 ) );

  const renderScene = new RenderPass( scene, camera );

  const bloomPass = new UnrealBloomPass( new THREE.Vector2( window.innerWidth, window.innerHeight ), 1.5, 0.4, 0.85 );
  bloomPass.threshold = params.bloomThreshold;
  bloomPass.strength = params.bloomStrength;
  bloomPass.radius = params.bloomRadius;

  const bloomComposer = new EffectComposer( renderer );
  bloomComposer.renderToScreen = false;
  bloomComposer.addPass( renderScene );
  bloomComposer.addPass( bloomPass );

  const finalPass = new ShaderPass(
    new THREE.ShaderMaterial( {
      uniforms: {
        baseTexture: { value: null },
        bloomTexture: { value: bloomComposer.renderTarget2.texture }
      },
      vertexShader: document.getElementById( 'vertexshader' ).textContent,
      fragmentShader: document.getElementById( 'fragmentshader' ).textContent,
      defines: {}
    } ), 'baseTexture'
  );
  finalPass.needsSwap = true;

  const finalComposer = new EffectComposer( renderer );
  finalComposer.addPass( renderScene );
  finalComposer.addPass( finalPass );

  setupScene();

  window.onresize = function () {

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

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

    renderer.setSize( width, height );

    bloomComposer.setSize( width, height );
    finalComposer.setSize( width, height );

    render();

  };

  function setupScene() {

    scene.traverse( disposeMaterial );
    scene.children.length = 0;

    const geometry = new THREE.IcosahedronGeometry( 1, 15 );
    const planeGeometry = new THREE.PlaneGeometry( 2, 2 );
    const planeMaterial = new THREE.MeshBasicMaterial({color: 0xffffff, transparent: true, opacity: 0.5, side: THREE.DoubleSide });
    plane = new THREE.Mesh( planeGeometry, planeMaterial );
    plane.scale.set(2, 2, 2);
    plane.position.z = 6;
    scene.add(plane);
    for ( let i = 0; i < 50; i ++ ) {

      const color = new THREE.Color();
      color.setHSL( Math.random(), 0.7, Math.random() * 0.2 + 0.05 );

      const material = new THREE.MeshBasicMaterial( { color: color } );
      const sphere = new THREE.Mesh( geometry, material );
      sphere.position.x = Math.random() * 10 - 5;
      sphere.position.y = Math.random() * 10 - 5;
      sphere.position.z = Math.random() * 2 - 5;
      sphere.position.normalize().multiplyScalar( Math.random() * 4.0 + 2.0 );
      sphere.scale.setScalar( Math.random() * Math.random() + 0.5 );
      scene.add( sphere );

      if ( Math.random() < 0.5 ) sphere.layers.enable( BLOOM_SCENE );

    }

    render();

  }

  function disposeMaterial( obj ) {

    if ( obj.material ) {

      obj.material.dispose();

    }

  }

  function render() {
    renderBloom();
    finalComposer.render();
  }

  function renderBloom( mask ) {

      scene.traverse( darkenNonBloomed );
      plane.visible = false;
      bloomComposer.render();
      scene.traverse( restoreMaterial );
      plane.visible = true;

  }

  function darkenNonBloomed( obj ) {
    
    if ( obj.isMesh && bloomLayer.test( obj.layers ) === false ) {

      materials[ obj.uuid ] = obj.material;
      obj.material = darkMaterial;

    }

  }

  function restoreMaterial( obj ) {
    
    if ( materials[ obj.uuid ] ) {

      obj.material = materials[ obj.uuid ];
      delete materials[ obj.uuid ];

    }

  }

</script>