javascript
/
three.js
mirror of https://github.com/tazdij/three.js.git


			
				
					
						
						
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							<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>Three.js - Picking - RayCaster</title>
    <style>
    html, body {
        height: 100%;
        margin: 0;
    }
    #c {
        width: 100%;
        height: 100%;
        display: block;
    }
    </style>
  </head>
  <body>
    <canvas id="c"></canvas>
  </body>
<script type="module">
import * as THREE from '../../build/three.module.js';

function main() {
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});

  const fov = 60;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 200;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.z = 30;

  const scene = new THREE.Scene();
  scene.background = new THREE.Color('white');

  // put the camera on a pole (parent it to an object)
  // so we can spin the pole to move the camera around the scene
  const cameraPole = new THREE.Object3D();
  scene.add(cameraPole);
  cameraPole.add(camera);

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

  const geometry = new THREE.SphereGeometry(.6, 100, 100);

  function rand(min, max) {
    if (max === undefined) {
      max = min;
      min = 0;
    }
    return min + (max - min) * Math.random();
  }

  function randomColor() {
    return `hsl(${rand(360) | 0}, ${rand(50, 100) | 0}%, 50%)`;
  }

  const numObjects = 100;
  for (let i = 0; i < numObjects; ++i) {
    const material = new THREE.MeshPhongMaterial({color: randomColor()});

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

    cube.position.set(rand(-20, 20), rand(-20, 20), rand(-20, 20));
    cube.rotation.set(rand(Math.PI), rand(Math.PI), 0);
    cube.scale.set(rand(3, 6), rand(3, 6), rand(3, 6));
  }

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

  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;
      }

      this.raycaster.setFromCamera(normalizedPosition, camera);
      const intersectedObjects = this.raycaster.intersectObjects(scene.children);
      if (intersectedObjects.length) {
        this.pickedObject = intersectedObjects[0].object;
        this.pickedObjectSavedColor = this.pickedObject.material.emissive.getHex();
        this.pickedObject.material.emissive.setHex((time * 8) % 2 > 1 ? 0xFFFF00 : 0xFF0000);
      }
    }
  }

  const pickHelper = new PickHelper();
  const pickPosition = {x: -1, y: -1};
  clearPickPosition();

  function render(time) {
    time *= 0.001;  // convert to seconds;

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

    cameraPole.rotation.y = time * .1;

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

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }
  requestAnimationFrame(render);

  function getCanvasRelativePosition(event) {
    const rect = canvas.getBoundingClientRect();
    return {
      x: (event.clientX - rect.left) * canvas.width  / rect.width,
      y: (event.clientY - rect.top ) * canvas.height / rect.height,
    };
  }

  function setPickPosition(event) {
    const pos = getCanvasRelativePosition(event);
    pickPosition.x = pos.x;
    pickPosition.y = pos.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;
  }

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

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

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

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

main();
</script>
</html>