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<title>three.js webgl - math - OBB</title>
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<a href="https://threejs.org" target="_blank" rel="noopener noreferrer">three.js</a> - OBB (Oriented Bounding Box)
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<!-- 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",
"three/addons/": "./jsm/"
}
}
</script>
<script type="module">
import * as THREE from 'three';
import { OBB } from 'three/addons/math/OBB.js';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import Stats from 'three/addons/libs/stats.module.js';
let camera, scene, renderer, clock, controls, stats, raycaster, hitbox;
const objects = [], mouse = new THREE.Vector2();
init();
animate();
function init() {
camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 1, 1000 );
camera.position.set( 0, 0, 75 );
scene = new THREE.Scene();
scene.background = new THREE.Color( 0xffffff );
clock = new THREE.Clock();
raycaster = new THREE.Raycaster();
const hemiLight = new THREE.HemisphereLight( 0xffffff, 0x222222, 1.5 );
hemiLight.position.set( 1, 1, 1 );
scene.add( hemiLight );
const size = new THREE.Vector3( 10, 5, 6 );
const geometry = new THREE.BoxGeometry( size.x, size.y, size.z );
// setup OBB on geometry level (doing this manually for now)
geometry.userData.obb = new OBB();
geometry.userData.obb.halfSize.copy( size ).multiplyScalar( 0.5 );
for ( let i = 0; i < 100; i ++ ) {
const object = new THREE.Mesh( geometry, new THREE.MeshLambertMaterial( { color: 0x00ff00 } ) );
object.matrixAutoUpdate = false;
object.position.x = Math.random() * 80 - 40;
object.position.y = Math.random() * 80 - 40;
object.position.z = Math.random() * 80 - 40;
object.rotation.x = Math.random() * 2 * Math.PI;
object.rotation.y = Math.random() * 2 * Math.PI;
object.rotation.z = Math.random() * 2 * Math.PI;
object.scale.x = Math.random() + 0.5;
object.scale.y = Math.random() + 0.5;
object.scale.z = Math.random() + 0.5;
scene.add( object );
// bounding volume on object level (this will reflect the current world transform)
object.userData.obb = new OBB();
objects.push( object );
}
//
hitbox = new THREE.Mesh( geometry, new THREE.MeshBasicMaterial( { color: 0x000000, wireframe: true } ) );
//
renderer = new THREE.WebGLRenderer( { antialias: true } );
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
//
controls = new OrbitControls( camera, renderer.domElement );
controls.enableDamping = true;
//
stats = new Stats();
document.body.appendChild( stats.dom );
//
window.addEventListener( 'resize', onWindowResize );
document.addEventListener( 'click', onClick );
}
function onClick( event ) {
event.preventDefault();
mouse.x = ( event.clientX / window.innerWidth ) * 2 - 1;
mouse.y = - ( event.clientY / window.innerHeight ) * 2 + 1;
raycaster.setFromCamera( mouse, camera );
const intersectionPoint = new THREE.Vector3();
const intersections = [];
for ( let i = 0, il = objects.length; i < il; i ++ ) {
const object = objects[ i ];
const obb = object.userData.obb;
const ray = raycaster.ray;
if ( obb.intersectRay( ray, intersectionPoint ) !== null ) {
const distance = ray.origin.distanceTo( intersectionPoint );
intersections.push( { distance: distance, object: object } );
}
}
if ( intersections.length > 0 ) {
// determine closest intersection and highlight the respective 3D object
intersections.sort( sortIntersections );
intersections[ 0 ].object.add( hitbox );
} else {
const parent = hitbox.parent;
if ( parent ) parent.remove( hitbox );
}
}
function sortIntersections( a, b ) {
return a.distance - b.distance;
}
function onWindowResize() {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize( window.innerWidth, window.innerHeight );
}
//
function animate() {
requestAnimationFrame( animate );
controls.update();
// transform cubes
const delta = clock.getDelta();
for ( let i = 0, il = objects.length; i < il; i ++ ) {
const object = objects[ i ];
object.rotation.x += delta * Math.PI * 0.20;
object.rotation.y += delta * Math.PI * 0.1;
object.updateMatrix();
object.updateMatrixWorld();
// update OBB
object.userData.obb.copy( object.geometry.userData.obb );
object.userData.obb.applyMatrix4( object.matrixWorld );
// reset
object.material.color.setHex( 0x00ff00 );
}
// collision detection
for ( let i = 0, il = objects.length; i < il; i ++ ) {
const object = objects[ i ];
const obb = object.userData.obb;
for ( let j = i + 1, jl = objects.length; j < jl; j ++ ) {
const objectToTest = objects[ j ];
const obbToTest = objectToTest.userData.obb;
// now perform intersection test
if ( obb.intersectsOBB( obbToTest ) === true ) {
object.material.color.setHex( 0xff0000 );
objectToTest.material.color.setHex( 0xff0000 );
}
}
}
renderer.render( scene, camera );
stats.update();
}
</script>
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