hw5: raycaster:pick

by jmchen

HTML

<div id="info">Picking Demo</div>
<script src="http://cdnjs.cloudflare.com/ajax/libs/three.js/r70/three.min.js"></script>
<script src="https://dl.dropboxusercontent.com/u/3587259/Code/Threejs/OrbitControls.js">
    
</script>

CSS

#info {
    position: absolute;
    top: 0px;
    width: 100%;
    padding: 10px;
    text-align: center;
    color: #ffff00
}

JavaScript

var camera, scene, renderer, light, controls;
var plane, picture;

var raycaster;
var mouse = new THREE.Vector2();
var pickables = [];

init();
animate();

function init() {
    scene = new THREE.Scene();

    camera = new THREE.PerspectiveCamera(50, window.innerWidth / window.innerHeight, 1, 1000);
    camera.position.z = 500;
    scene.add(camera);

    var geometry = new THREE.PlaneGeometry(80, 80);
    plane = new THREE.Mesh(geometry, new THREE.MeshBasicMaterial());
    plane.rotation.y = Math.PI / 12;
    scene.add(plane);

    picture = new THREE.Mesh(
    new THREE.PlaneGeometry(10, 10),
    new THREE.MeshBasicMaterial({
        color: 0xff0000,
        polygonOffset: true,
        polygonOffsetUnits: -4.0,
        polygonOffsetFactor: -1.0,
    }));
    scene.add(picture);

    pickables = [plane];

    light = new THREE.PointLight(0xffffff);
    light.position.set(100, 300, 200);
    scene.add(light);

    var gridXZ = new THREE.GridHelper(100, 10);
    gridXZ.setColors(new THREE.Color(0xff0000), new THREE.Color(0xffffff));
    scene.add(gridXZ);

    renderer = new THREE.WebGLRenderer();
    renderer.setSize(window.innerWidth, window.innerHeight);
    renderer.setClearColor(0x888888);

    controls = new THREE.OrbitControls(camera, renderer.domElement);

    document.body.appendChild(renderer.domElement);

    raycaster = new THREE.Raycaster();
    document.addEventListener('mousedown', onDocumentMouseDown, false);
    document.addEventListener('mousemove', onDocumentMouseMove, false);
}

function onDocumentMouseDown(event) {

    // PICKING DETAILS: 
    // convert mouse.xy = [-1,1]^2 (NDC)
    // unproject (mouse.xy, 1) to a point on the far plane (in world coordinate)
    // set raycaster (origin, direction)
    // find intersection objects, (closest first) 
    // each record as
    // [ { distance, point, face, faceIndex, object }, ... ]

    event.preventDefault();
    debugger;
    mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
   ...