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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 w/Transparency</title>
<style>
html, body {
height: 100%;
margin: 0;
}
#c {
width: 100%;
height: 100%;
display: block;
}
</style>
</head>
<body>
<canvas id="c"></canvas>
</body>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>
<script type="importmap">
{
"imports": {
"three": "../../build/three.module.js"
}
}
</script>
<script type="module">
import * as THREE from 'three';
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 boxWidth = 1;
const boxHeight = 1;
const boxDepth = 1;
const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);
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 loader = new THREE.TextureLoader();
const texture = loader.load('resources/images/frame.png');
const numObjects = 100;
for (let i = 0; i < numObjects; ++i) {
const material = new THREE.MeshPhongMaterial({
color: randomColor(),
map: texture,
transparent: true,
side: THREE.DoubleSide,
alphaTest: 0.1,
});
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;
}
// 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: 0, y: 0};
const pickHelper = new PickHelper();
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 / canvas.width ) * 2 - 1;
pickPosition.y = (pos.y / canvas.height) * -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;
}
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>