var scene, width, height, camera, cubeCamera, renderer, toruses, box;

​

init();

function init() {

  var boxGeometry, boxMaterial, light;

​

  scene = new THREE.Scene();

  width = window.innerWidth;

  height = window.innerHeight;

  camera = new THREE.PerspectiveCamera(45, width / height, 0.1, 1000);

  cubeCamera = new THREE.CubeCamera(1, 1000, 20);

  renderer = new THREE.WebGLRenderer();

  toruses = [];

​

  boxGeometry = new THREE.BoxGeometry(2, 2, 2);

  boxMaterial = new THREE.MeshBasicMaterial({ 

    envMap: cubeCamera.renderTarget,

    reflectivity: 0.8,

    color: 0xFFFFFF

  });

  box = new THREE.Mesh(boxGeometry, boxMaterial);

  box.position.set(0, 0, 0);

  scene.add(box);

​

  renderer.setSize(width, height);

  renderer.setClearColor(0x17293a);

​

  cubeCamera.position.set(0, 0, 0);

  scene.add(cubeCamera);

  camera.position.set(0, -50, 0);

  camera.lookAt(scene.position);

​

  generateToruses(200, 10);

​

  document.body.appendChild(renderer.domElement);

​

  drawFrame();

}

​

function generateToruses(num, step) {

  var torusGeometry, torusMaterial, torus,

      radius, colors;

​

  colors = ['#f1c40f', '#f39c12', '#e67e22', '#d35400', '#e74c3c', '#c0392b'];

​

  for (var i = -num; i < num; i += step) {

    radius = 4 + Math.random() * 8;

    torusGeometry = new THREE.TorusGeometry(radius, 1, 8, 30, Math.PI * 2);

    torusMaterial = new THREE.MeshBasicMaterial({color: colors[Math.floor(Math.random() * colors.length)]});

    torus = new THREE.Mesh(torusGeometry, torusMaterial);

    torus.position.set(0, 0, i);

    torus.rotation.set(-0.1 + Math.random() * 0.2, -0.3 + Math.random() * 0.6, 0);

    scene.add(torus);

    toruses.push(torus);

  }

}

​

function drawFrame() {

  var speed = 0.05;

  window.requestAnimationFrame(drawFrame);

  renderer.render(scene, camera);

  box.rotation.z += speed;

  box.rotation.y += speed;

  toruses.forEach(moveTorus);

  cubeCamera.visible = false;

  cubeCamera.updateCubeMap( renderer, scene );

  cubeCamera.visible = true;

}

​

function moveTorus(torus) {

  torus.position.z += 0.6;

  if (torus.position.z >= 200) torus.position.z = -200;

}