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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="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( { antialias: true, 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 = 3;
- 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 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;
- }
- // 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>
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