three.js/threejs/shared-orbitcontrols.js

function init(data) {   /* eslint-disable-line no-unused-vars */
  const {canvas, inputElement} = data;
  const renderer = new THREE.WebGLRenderer({canvas});

  const fov = 75;
  const aspect = 2; // the canvas default
  const near = 0.1;
  const far = 100;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.z = 4;

  const controls = new THREE.OrbitControls(camera, inputElement);
  controls.target.set(0, 0, 0);
  controls.update();

  const scene = new THREE.Scene();

  {
    const color = 0xFFFFFF;
    const intensity = 1;
    const light = new THREE.DirectionalLight(color, intensity);
    light.position.set(-1, 2, 4);
    scene.add(light);
  }

  const boxWidth = 1;
  const boxHeight = 1;
  const boxDepth = 1;
  const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);

  function makeInstance(geometry, color, x) {
    const material = new THREE.MeshPhongMaterial({
      color,
    });

    const cube = new THREE.Mesh(geometry, material);
    scene.add(cube);

    cube.position.x = x;

    return cube;
  }

  const cubes = [
    makeInstance(geometry, 0x44aa88, 0),
    makeInstance(geometry, 0x8844aa, -2),
    makeInstance(geometry, 0xaa8844, 2),
  ];

  class PickHelper {
    constructor() {
      this.raycaster = new THREE.Raycaster();
      this.pickedObject = null;
      this.pickedObjectSavedColor = 0;
    }
    pick(normalizedPosition, scene, camera, time) {
      // restore the color if there is a picked object
      if (this.pickedObject) {
        this.pickedObject.material.emissive.setHex(this.pickedObjectSavedColor);
        this.pickedObject = undefined;
      }

      // cast a ray through the frustum
      this.raycaster.setFromCamera(normalizedPosition, camera);
      // get the list of objects the ray intersected
      const intersectedObjects = this.raycaster.intersectObjects(scene.children);
      if (intersectedObjects.length) {
        // pick the first object. It's the closest one
        this.pickedObject = intersectedObjects[0].object;
        // save its color
        this.pickedObjectSavedColor = this.pickedObject.material.emissive.getHex();
        // set its emissive color to flashing red/yellow
        this.pickedObject.material.emissive.setHex((time * 8) % 2 > 1 ? 0xFFFF00 : 0xFF0000);
      }
    }
  }

  const pickPosition = {x: -2, y: -2};
  const pickHelper = new PickHelper();
  clearPickPosition();

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = inputElement.clientWidth;
    const height = inputElement.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  function render(time) {
    time *= 0.001;

    if (resizeRendererToDisplaySize(renderer)) {
      camera.aspect = inputElement.clientWidth / inputElement.clientHeight;
      camera.updateProjectionMatrix();
    }

    cubes.forEach((cube, ndx) => {
      const speed = 1 + ndx * .1;
      const rot = time * speed;
      cube.rotation.x = rot;
      cube.rotation.y = rot;
    });

    pickHelper.pick(pickPosition, scene, camera, time);

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);

  function getCanvasRelativePosition(event) {
    const rect = inputElement.getBoundingClientRect();
    return {
      x: event.clientX - rect.left,
      y: event.clientY - rect.top,
    };
  }

  function setPickPosition(event) {
    const pos = getCanvasRelativePosition(event);
    pickPosition.x = (pos.x / inputElement.clientWidth ) *  2 - 1;
    pickPosition.y = (pos.y / inputElement.clientHeight) * -2 + 1;  // note we flip Y
  }

  function clearPickPosition() {
    // unlike the mouse which always has a position
    // if the user stops touching the screen we want
    // to stop picking. For now we just pick a value
    // unlikely to pick something
    pickPosition.x = -100000;
    pickPosition.y = -100000;
  }

  inputElement.addEventListener('mousemove', setPickPosition);
  inputElement.addEventListener('mouseout', clearPickPosition);
  inputElement.addEventListener('mouseleave', clearPickPosition);

  inputElement.addEventListener('touchstart', (event) => {
    // prevent the window from scrolling
    event.preventDefault();
    setPickPosition(event.touches[0]);
  }, {passive: false});

  inputElement.addEventListener('touchmove', (event) => {
    setPickPosition(event.touches[0]);
  });

  inputElement.addEventListener('touchend', clearPickPosition);
}