从零开始Vue项目中使用MapboxGL开发三维地图教程（七）创建一个自动旋转的地球、添加一个3D模型、实现在两个地图之间滑动和同步来比较两个地图

╰+哭是因爲堅強的太久メ 2023-10-12 17:23 22阅读 0赞

#### 目录 ####

*   *   *  1、创建一个自动旋转的地球地图
         *  2、添加一个3D模型
         *  3、一个页面创建两个底图之间滑动

#### 1、创建一个自动旋转的地球地图 ####

实现功能：地球仪和camera动画结合在一起，创建旋转行星效果。

实现思路：通过在动画结束时调用easeTo，旋转动画将无限期地继续。旋转在用户交互时暂停，并且在高缩放级别时减慢到停止。

首先在dom中添加一个button：

<button id="btn-spin">Pause rotation</button>

实现代码：

map.on('style.load', () => {
        
    					map.setFog({
        }); // Set the default atmosphere style
    				});
    
    				// The following values can be changed to control rotation speed:
    
    				// At low zooms, complete a revolution every two minutes.
    				const secondsPerRevolution = 120;
    				// Above zoom level 5, do not rotate.
    				const maxSpinZoom = 5;
    				// Rotate at intermediate speeds between zoom levels 3 and 5.
    				const slowSpinZoom = 3;
    
    				let userInteracting = false;
    				let spinEnabled = true;
    
    				function spinGlobe() {
        
    					const zoom = map.getZoom();
    					if (spinEnabled && !userInteracting && zoom < maxSpinZoom) {
        
    						let distancePerSecond = 360 / secondsPerRevolution;
    						if (zoom >
    							slowSpinZoom) {
        
    							// Slow spinning at higher zooms
    							const zoomDif =
    								(maxSpinZoom - zoom) / (maxSpinZoom - slowSpinZoom);
    							distancePerSecond *= zoomDif;
    						}
    						const center = map.getCenter();
    						center.lng -= distancePerSecond;
    						// Smoothly animate the map over one second.
    						// When this animation is complete, it calls a 'moveend' event.
    						map.easeTo({
        
    							center,
    							duration: 1000,
    							easing: (n) => n
    						});
    					}
    				}
    
    				// Pause spinning on interaction
    				map.on('mousedown', () => {
        
    					userInteracting = true;
    				});
    
    				// Restart spinning the globe when interaction is complete
    				map.on('mouseup', () => {
        
    					userInteracting = false;
    					spinGlobe();
    				});
    
    				// These events account for cases where the mouse has moved
    				// off the map, so 'mouseup' will not be fired.
    				map.on('dragend', () => {
        
    					userInteracting = false;
    					spinGlobe();
    				});
    				map.on('pitchend', () => {
        
    					userInteracting = false;
    					spinGlobe();
    				});
    				map.on('rotateend', () => {
        
    					userInteracting = false;
    					spinGlobe();
    				});
    
    				// When animation is complete, start spinning if there is no ongoing interaction
    				map.on('moveend', () => {
        
    					spinGlobe();
    				});
    
    				document.getElementById('btn-spin').addEventListener('click', (e) => {
        
    					spinEnabled = !spinEnabled;
    					if (spinEnabled) {
        
    						spinGlobe();
    						e.target.innerHTML = 'Pause rotation';
    					} else {
        
    						map.stop(); // Immediately end ongoing animation
    						e.target.innerHTML = 'Start rotation';
    					}
    				});
    
    				spinGlobe();

效果展示：  
![在这里插入图片描述][edd7c20822394473a4a74a151d10399b.gif]

#### 2、添加一个3D模型 ####

使用three.js,首先three.js安装到项目中：

# three.js
    npm install --save three

在项目中引入：

import * as THREE from 'three';
    	import {
        
    		GLTFLoader
    	} from 'three/examples/jsm/loaders/GLTFLoader.js';

使用带有three.js的自定义样式层将三维模型添加到地图中：

// parameters to ensure the model is georeferenced correctly on the map
    				const modelOrigin = [104.9819, 37.39847];
    				const modelAltitude = 0;
    				const modelRotate = [Math.PI / 2, 0, 0];
    
    				const modelAsMercatorCoordinate = this.$mapboxgl.MercatorCoordinate.fromLngLat(
    					modelOrigin,
    					modelAltitude
    				);
    
    				// transformation parameters to position, rotate and scale the 3D model onto the map
    				const modelTransform = {
        
    					translateX: modelAsMercatorCoordinate.x,
    					translateY: modelAsMercatorCoordinate.y,
    					translateZ: modelAsMercatorCoordinate.z,
    					rotateX: modelRotate[0],
    					rotateY: modelRotate[1],
    					rotateZ: modelRotate[2],
    					/* Since the 3D model is in real world meters, a scale transform needs to be
    					 * applied since the CustomLayerInterface expects units in MercatorCoordinates.
    					 */
    					scale: modelAsMercatorCoordinate.meterInMercatorCoordinateUnits()
    				};
    
    				// const THREE = window.THREE;
    
    				// configuration of the custom layer for a 3D model per the CustomLayerInterface
    				const customLayer = {
        
    					id: '3d-model',
    					type: 'custom',
    					renderingMode: '3d',
    					onAdd: function (map, gl) {
        
    						this.camera = new THREE.Camera();
    						this.scene = new THREE.Scene();
    
    						// create two three.js lights to illuminate the model
    						const directionalLight = new THREE.DirectionalLight(0xffffff);
    						directionalLight.position.set(0, -70, 100).normalize();
    						this.scene.add(directionalLight);
    
    						const directionalLight2 = new THREE.DirectionalLight(0xffffff);
    						directionalLight2.position.set(0, 70, 100).normalize();
    						this.scene.add(directionalLight2);
    
    						// use the three.js GLTF loader to add the 3D model to the three.js scene
    						const loader = new GLTFLoader();
    						loader.load(
    							'https://docs.mapbox.com/mapbox-gl-js/assets/34M_17/34M_17.gltf',
    							(gltf) => {
        
    								this.scene.add(gltf.scene);
    							}
    						);
    						this.map = map;
    
    						// use the Mapbox GL JS map canvas for three.js
    						this.renderer = new THREE.WebGLRenderer({
        
    							canvas: map.getCanvas(),
    							context: gl,
    							antialias: true
    						});
    
    						this.renderer.autoClear = false;
    					},
    					render: function (gl, matrix) {
        
    						const rotationX = new THREE.Matrix4().makeRotationAxis(
    							new THREE.Vector3(1, 0, 0),
    							modelTransform.rotateX
    						);
    						const rotationY = new THREE.Matrix4().makeRotationAxis(
    							new THREE.Vector3(0, 1, 0),
    							modelTransform.rotateY
    						);
    						const rotationZ = new THREE.Matrix4().makeRotationAxis(
    							new THREE.Vector3(0, 0, 1),
    							modelTransform.rotateZ
    						);
    
    						const m = new THREE.Matrix4().fromArray(matrix);
    						const l = new THREE.Matrix4()
    							.makeTranslation(
    								modelTransform.translateX,
    								modelTransform.translateY,
    								modelTransform.translateZ
    							)
    							.scale(
    								new THREE.Vector3(
    									modelTransform.scale,
    									-modelTransform.scale,
    									modelTransform.scale
    								)
    							)
    							.multiply(rotationX)
    							.multiply(rotationY)
    							.multiply(rotationZ);
    
    						this.camera.projectionMatrix = m.multiply(l);
    						// this.renderer.resetState();
    						this.renderer.render(this.scene, this.camera);
    						this.map.triggerRepaint();
    					}
    				};
    
    				map.on('style.load', () => {
        
    					map.addLayer(customLayer, 'waterway-label');
    				});

上效果：  
![在这里插入图片描述][b973e57481d9414c83daa934b21a6060.png]

#### 3、一个页面创建两个底图之间滑动 ####

以通过左右滑动来比较两个地图

使用mapbox插件 mapbox-gl-compare  
安装

npm i mapbox-gl-compare -D
    npm i mapbox-gl-sync-move -D

导入

import mapboxgl from ‘mapbox-gl’
    import Compare from ‘mapbox-gl-compare’

创建两个div：

核心代码：

mapboxgl.accessToken = 'xxxxxxx';
        const beforeMap = new mapboxgl.Map({
        
            container: 'before',
            // Choose from Mapbox's core styles, or make your own style with Mapbox Studio
            style: 'mapbox://styles/mapbox/streets-v12',
            center: [0, 0],
            zoom: 0
        });
    
        const afterMap = new mapboxgl.Map({
        
            container: 'after',
            style: 'mapbox://styles/mapbox/satellite-streets-v12',
            center: [0, 0],
            zoom: 0
        });
    
        // A selector or reference to HTML element
        const container = '#comparison-container';
    
        const map = new mapboxgl.Compare(beforeMap, afterMap, container, {
        
            // Set this to enable comparing two maps by mouse movement:
            // mousemove: true
        });

效果如下：  
![在这里插入图片描述][182dc239ce024953955e401dff7156ff.gif]

[edd7c20822394473a4a74a151d10399b.gif]: https://img-blog.csdnimg.cn/edd7c20822394473a4a74a151d10399b.gif
[b973e57481d9414c83daa934b21a6060.png]: https://img-blog.csdnimg.cn/b973e57481d9414c83daa934b21a6060.png
[182dc239ce024953955e401dff7156ff.gif]: https://img-blog.csdnimg.cn/182dc239ce024953955e401dff7156ff.gif