1. 引言
3D Tiles 是 3D GIS 中常见的三维数据格式，能否用Three.js来加载渲染呢？肯定是可以，Three.js只是一个WebGL框架，渲染数据肯定可以，但是加载、解析数据得手动解决
有没有一个第三方库解决这个问题呢？有，比如这个：NASA-AMMOS/3DTilesRendererJS: Renderer for 3D Tiles in Javascript using three.js (github.com)
这里就简要记录如何在Three.js中加载 3D Tiles
2. 加载3D Tiles
首先，搭建一个简单的三维场景
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <style> html, body, canvas { height: 100%; width: 100%; margin: 0; } </style> </head> <body> <canvas id="canvas"></canvas> <script type="importmap"> { "imports": { "three": "https://unpkg.com/three/build/three.module.js", "three/addons/": "https://unpkg.com/three/examples/jsm/" } } </script> <script type="module"> import * as THREE from 'three'; import { OrbitControls } from 'three/addons/controls/OrbitControls.js'; const scene = new THREE.Scene(); const canvas = document.querySelector('#canvas'); const camera = new THREE.PerspectiveCamera(75, canvas.clientWidth / canvas.clientHeight , 0.1, 1000); camera.position.z = 5; const renderer = new THREE.WebGLRenderer({ canvas: document.querySelector('#canvas') }); renderer.setSize(window.innerWidth, window.innerHeight, false) const geometry = new THREE.BoxGeometry(1, 1, 1); const material = new THREE.MeshPhongMaterial({ color: 0x00ff00 }); const cube = new THREE.Mesh(geometry, material); scene.add(cube); const light = new THREE.DirectionalLight(0xffffff, 1); light.position.set(0, 0, 5); scene.add(light); const controls = new OrbitControls( camera, renderer.domElement ); function animate() { requestAnimationFrame(animate); cube.rotation.x += 0.01; cube.rotation.y += 0.01; renderer.render(scene, camera); } animate(); </script> </body> </html> 
然后是引入3DTilesRendererJS，这里引入的是GoogleTilesRenderer来加载Google的在线地图，另外还需要使用GLTFLoader和DRACOLoader以进行数据解析
<script type="importmap"> { "imports": { "three": "https://unpkg.com/three/build/three.module.js", "three/addons/": "https://unpkg.com/three/examples/jsm/", "3DTilesRendererJS": "https://cdn.jsdelivr.net/npm/3d-tiles-renderer@0.3.30/+esm" } } </script> <script type="module"> import * as THREE from 'three'; import { OrbitControls } from 'three/addons/controls/OrbitControls.js'; import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js'; import { TilesRenderer, GoogleTilesRenderer } from '3DTilesRendererJS' import { DRACOLoader } from 'three/addons/loaders/DRACOLoader.js'; // ... </script> 下一步是加载谷歌在线3D Tiles并加入场景中
const tilesRenderer = new GoogleTilesRenderer( 'AIzaSyBQ7Wj99aTxRqET-22qYWGFcDCWgVDt89A' ); // 传入的是谷歌倾斜摄影的API key tilesRenderer.setLatLonToYUp( 36.266494 * THREE.MathUtils.DEG2RAD, 120.460205 * THREE.MathUtils.DEG2RAD ); // Tokyo Tower tilesRenderer.setCamera( camera ); tilesRenderer.setResolutionFromRenderer( camera, renderer ); const dracoLoader = new DRACOLoader(); dracoLoader.setDecoderPath( 'https://unpkg.com/three@0.153.0/examples/jsm/libs/draco/gltf/' ); const loader = new GLTFLoader( tilesRenderer.manager ); loader.setDRACOLoader( dracoLoader ); tilesRenderer.manager.addHandler( /.gltf$/, loader ); scene.add( tilesRenderer.group ); 最后在每一帧中更新3D Tiles渲染器
function animate() { requestAnimationFrame(animate); tilesRenderer.update(); // ... renderer.render(scene, camera); } 加载的结果如下：
完整代码如下：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <style> html, body, canvas { height: 100%; width: 100%; margin: 0; } </style> </head> <body> <canvas id="canvas"></canvas> <script type="importmap"> { "imports": { "three": "https://unpkg.com/three/build/three.module.js", "three/addons/": "https://unpkg.com/three/examples/jsm/" } } </script> <script type="module"> import * as THREE from 'three'; import { OrbitControls } from 'three/addons/controls/OrbitControls.js'; import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js'; import { TilesRenderer, GoogleTilesRenderer } from 'https://cdn.jsdelivr.net/npm/3d-tiles-renderer@0.3.30/+esm' import { DRACOLoader } from 'three/addons/loaders/DRACOLoader.js'; const scene = new THREE.Scene(); const canvas = document.querySelector('#canvas'); const camera = new THREE.PerspectiveCamera(75, canvas.clientWidth / canvas.clientHeight , 0.1, 100000); camera.position.y = 500; camera.position.z = 500; const renderer = new THREE.WebGLRenderer({ canvas: document.querySelector('#canvas') }); renderer.setSize(window.innerWidth, window.innerHeight, false) const controls = new OrbitControls( camera, renderer.domElement ); const tilesRenderer = new GoogleTilesRenderer( 'AIzaSyBQ7Wj99aTxRqET-22qYWGFcDCWgVDt89A' ); tilesRenderer.setLatLonToYUp( 35.6586 * THREE.MathUtils.DEG2RAD, 139.7454 * THREE.MathUtils.DEG2RAD ); // Tokyo Tower tilesRenderer.setCamera( camera ); tilesRenderer.setResolutionFromRenderer( camera, renderer ); const dracoLoader = new DRACOLoader(); dracoLoader.setDecoderPath( 'https://unpkg.com/three@0.153.0/examples/jsm/libs/draco/gltf/' ); const loader = new GLTFLoader( tilesRenderer.manager ); loader.setDRACOLoader( dracoLoader ); tilesRenderer.manager.addHandler( /.gltf$/, loader ); scene.add( tilesRenderer.group ); function animate() { requestAnimationFrame(animate); tilesRenderer.update(); renderer.render(scene, camera); } animate(); </script> </body> </html> 上面加载的是日本东京的倾斜摄影数据，那在没有倾斜摄影数据的地方呢，比如中国的某些城市，答案是会加载类似于高程与遥感影像的合成数据，如下图：
此时只是把经纬度做以下修改：
tilesRenderer.setLatLonToYUp( 36.266494 * THREE.MathUtils.DEG2RAD, 120.460205 * THREE.MathUtils.DEG2RAD ); // 山东青岛 总的来说，有时可以在Three.js中加载这样的3D Tiles作为底图来使用，更多的使用方法可参考官方文档：NASA-AMMOS/3DTilesRendererJS: Renderer for 3D Tiles in Javascript using three.js (github.com)
3. 参考资料
[1] NASA-AMMOS/3DTilesRendererJS: Renderer for 3D Tiles in Javascript using three.js (github.com)
[2] 3D Tiles Renderer Options Example (nasa-ammos.github.io)
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