ThreeJS 案例-将2d元素附加到3d物体上

原理：利用 CSS2DObject 将二维物体转为 threejs 可以识别的 3d 物品，然后利用 CSS2DRenderer 将其渲染到页面，以下注释中步骤 4 和步骤 6 最为重要
使用场景：常常用来标志 3d 物体或者制作信息展示面板
<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
    <title>three.js css2d - label</title>
    <link type="text/css" rel="stylesheet" href="main.css">
    <style>
        .label {
            color: #FFF;
            font-family: sans-serif;
            padding: 2px;
            background: rgba(0, 0, 0, .6);
        }

    </style>
</head>

<body>
    <div id="info"><a href="http://threejs.org" target="_blank" rel="noopener">three.js</a> css2d - label</div>

    <script type="module">

        import * as THREE from '../build/three.module.js';

            import { OrbitControls } from './jsm/controls/OrbitControls.js';
            import { CSS2DRenderer, CSS2DObject } from './jsm/renderers/CSS2DRenderer.js';

            var camera, scene, renderer, labelRenderer;

            var clock = new THREE.Clock();
            var textureLoader = new THREE.TextureLoader();

            var earth, moon;

            init();
            animate();

            function init() {
                // 1、创建场景，相机，光源
                var EARTH_RADIUS = 1;
                camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 1, 1000 );
                camera.position.set( 10, 5, 20 );
                scene = new THREE.Scene();
                var dirLight = new THREE.DirectionalLight( 0xffffff );
                dirLight.position.set( 0, 0, 1 );
                scene.add( dirLight );
                // 2、创建地球 Mesh
                var earthGeometry = new THREE.SphereBufferGeometry( EARTH_RADIUS, 16, 16 );
                var earthMaterial = new THREE.MeshPhongMaterial( {
                    specular: 0x333333,
                    shininess: 5,
                    map: textureLoader.load( 'textures/planets/earth_atmos_2048.jpg' ),
                    specularMap: textureLoader.load( 'textures/planets/earth_specular_2048.jpg' ),
                    normalMap: textureLoader.load( 'textures/planets/earth_normal_2048.jpg' ),
                    normalScale: new THREE.Vector2( 0.85, 0.85 )
                } );
                earth = new THREE.Mesh( earthGeometry, earthMaterial );
                scene.add( earth );

                // 3、创建地球Label(二维物品)
                var earthDiv = document.createElement( 'div' );
                earthDiv.className = 'label';
                earthDiv.textContent = 'Earth';
                earthDiv.style.marginTop = '-1em';
                var earthLabel = new CSS2DObject( earthDiv );
                earthLabel.position.set( 0, EARTH_RADIUS, 0 );
                // 4、将 label 挂载到 3d 物品上
                earth.add( earthLabel );

                // 5、分别创建 WebGLRenderer 和 CSS2DRenderer
                renderer = new THREE.WebGLRenderer();
                renderer.setPixelRatio( window.devicePixelRatio );
                renderer.setSize( window.innerWidth, window.innerHeight );
                document.body.appendChild( renderer.domElement );

                labelRenderer = new CSS2DRenderer();
                labelRenderer.setSize( window.innerWidth, window.innerHeight );
                labelRenderer.domElement.style.position = 'absolute';
                labelRenderer.domElement.style.top = 0;
                document.body.appendChild( labelRenderer.domElement );

                var controls = new OrbitControls( camera, labelRenderer.domElement );

            }

            function animate() {

                requestAnimationFrame( animate );
                // 6、每帧执行两个渲染器
                renderer.render( scene, camera );
                labelRenderer.render( scene, camera );
            }

        </script>
</body>

</html>
效果：
最后编辑于：2019.12.03 15:35:54