面试官说：加入甲方需要在现场飞了100架无人机，并规划了路线，要我在在cesium里面加载处理，让我说说步骤如何在cesium里面写，我应该怎么说

本文链接：https://blog.youkuaiyun.com/weixin_51647998/article/details/147907164

# 在Cesium中加载和处理100架无人机飞行路线的完整方案

## 一、前期数据准备

1. **无人机数据格式标准化**
- 确保所有无人机路径数据为统一格式（建议GeoJSON或CZML）
- 每条路径应包含：
```json
{
"droneId": "UAV001",
"path": [[经度1,纬度1,高度1],[经度2,纬度2,高度2],...],
"properties": {
"speed": 10, // m/s
"color": "#FF0000",
"model": "quadcopter"
}
}
```

2. **三维模型准备**
- 准备轻量化的无人机GLTF模型（建议<500KB/个）
- 不同机型应有不同外观区分

## 二、Cesium实现步骤

### 1. 基础场景搭建

```javascript
const viewer = new Cesium.Viewer('cesiumContainer', {
terrainProvider: Cesium.createWorldTerrain(),
timeline: true,
animation: true // 启用时间轴和动画控制
});

// 优化设置以适应大量实体
viewer.scene.globe.depthTestAgainstTerrain = true;
viewer.scene.fxaa = true;
```

### 2. 批量加载无人机路径

```javascript
async function loadDronePaths() {
const response = await fetch('drones_paths.geojson');
const droneData = await response.json();

droneData.features.forEach((drone, index) => {
// 创建路径线
viewer.entities.add({
name: `Drone-${drone.properties.droneId}-Path`,
polyline: {
positions: Cesium.Cartesian3.fromDegreesArrayHeights(
drone.geometry.coordinates.flat()
),
width: 2,
material: new Cesium.PolylineGlowMaterialProperty({
glowPower: 0.2,
color: Cesium.Color.fromCssColorString(drone.properties.color)
})
}
});

// 创建无人机模型
const droneEntity = viewer.entities.add({
name: `Drone-${drone.properties.droneId}`,
position: Cesium.Cartesian3.fromDegrees(
drone.geometry.coordinates[0][0],
drone.geometry.coordinates[0][1],
drone.geometry.coordinates[0][2]
),
model: {
uri: `models/${drone.properties.model}.gltf`,
minimumPixelSize: 32,
maximumScale: 200
},
path: {
resolution: 1,
material: new Cesium.PolylineGlowMaterialProperty({
glowPower: 0.1,
color: Cesium.Color.fromCssColorString(drone.properties.color)
}),
width: 3,
leadTime: 0,
trailTime: 60 // 显示60秒轨迹尾迹
}
});

// 添加路径动画
animateDrone(droneEntity, drone.geometry.coordinates, drone.properties.speed);
});
}
```

### 3. 无人机路径动画实现

```javascript
function animateDrone(entity, coordinates, speed) {
const property = new Cesium.SampledPositionProperty();
const startTime = Cesium.JulianDate.fromDate(new Date());

let cumulativeDistance = 0;
const distances = [0];

// 计算各段距离和总距离
for (let i = 1; i < coordinates.length; i++) {
const prev = Cesium.Cartesian3.fromDegrees(
coordinates[i-1][0], coordinates[i-1][1], coordinates[i-1][2]
);
const curr = Cesium.Cartesian3.fromDegrees(
coordinates[i][0], coordinates[i][1], coordinates[i][2]
);
cumulativeDistance += Cesium.Cartesian3.distance(prev, curr);
distances.push(cumulativeDistance);
}

const totalTime = cumulativeDistance / speed;

// 添加位置采样点
coordinates.forEach((coord, i) => {
const time = Cesium.JulianDate.addSeconds(
startTime,
(distances[i] / cumulativeDistance) * totalTime,
new Cesium.JulianDate()
);
property.addSample(time, Cesium.Cartesian3.fromDegrees(
coord[0], coord[1], coord[2]
));
});

entity.position = property;
entity.orientation = new Cesium.VelocityOrientationProperty(property);

// 添加到时钟控制
viewer.clock.startTime = startTime.clone();
viewer.clock.stopTime = Cesium.JulianDate.addSeconds(
startTime, totalTime, new Cesium.JulianDate()
);
viewer.clock.currentTime = startTime.clone();
viewer.clock.clockRange = Cesium.ClockRange.LOOP_STOP;
viewer.clock.multiplier = 1;
}
```

### 4. 性能优化措施

```javascript
// 1. 实例化渲染优化
viewer.scene.primitives.add(new Cesium.ModelInstanceCollection({
url: 'models/quadcopter.gltf',
instances: droneEntities.map(entity => ({
modelMatrix: entity.computeModelMatrix(viewer.clock.currentTime),
attributes: {
color: new Cesium.ColorGeometryInstanceAttribute(1.0, 0.0, 0.0, 1.0)
}
}))
}));

// 2. 细节层次控制
viewer.scene.globe.maximumScreenSpaceError = 2;

// 3. 视锥体裁剪优化
viewer.scene.camera.frustumSplits = [0.1, 1e6, 2e6, 3e6];

// 4. 按需显示控制
function updateVisibility() {
const cameraPosition = viewer.camera.position;
droneEntities.forEach(entity => {
const distance = Cesium.Cartesian3.distance(
cameraPosition,
entity.position.getValue(viewer.clock.currentTime)
);
entity.show = distance < 5000; // 5公里内可见
});
}
viewer.scene.postUpdate.addEventListener(updateVisibility);
```

### 5. 交互功能实现

```javascript
// 无人机选择高亮
let selectedDrone = null;
viewer.screenSpaceEventHandler.setInputAction((click) => {
const pickedObject = viewer.scene.pick(click.position);
if (Cesium.defined(pickedObject) && pickedObject.id.name.includes('Drone')) {
// 移除之前的选择效果
if (selectedDrone) {
selectedDrone.model.color = Cesium.Color.WHITE;
}

// 设置新的选择效果
selectedDrone = pickedObject.id;
selectedDrone.model.color = Cesium.Color.YELLOW;

// 显示信息框
viewer.selectedEntity = selectedDrone;
}
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);

// 视角跟随功能
function followDrone(droneEntity) {
viewer.trackedEntity = droneEntity;
viewer.camera.flyTo({
destination: Cesium.Cartesian3.fromDegrees(
droneEntity.position.getValue(viewer.clock.currentTime),
orientation: {
heading: Cesium.Math.toRadians(0),
pitch: Cesium.Math.toRadians(-30),
roll: 0.0
}
});
}
```

## 三、现场实施建议

1. **数据验证阶段**
- 先加载5-10架验证效果
- 检查坐标系一致性（WGS84）
- 验证高度是否为椭球高

2. **性能监控**
```javascript
// 添加性能监视器
const performanceMonitor = new Cesium.PerformanceMonitor({
scene: viewer.scene,
container: document.getElementById('perf-monitor')
});
```

3. **异常处理**
```javascript
// 全局错误捕获
viewer.dataSources.dataSourceError.addEventListener((error) => {
console.error('DataSource error:', error);
});
```

4. **分级加载策略**
- 首次加载显示关键无人机
- 滚动加载剩余无人机
- 根据网络状况动态调整细节

## 四、预期成果

1. **可视化效果**
- 100架无人机沿预定路径平滑飞行
- 每架无人机可单独选择查看详情
- 实时显示飞行状态和轨迹

2. **性能指标**
- 60fps流畅动画（中端显卡）
- 内存占用<2GB
- 加载时间<15秒（100Mbps网络）

3. **交互功能**
- 时间轴控制播放
- 单体/群体显示切换
- 碰撞检测预警

这种实现方案既保证了大规模无人机场景的流畅展示，又提供了丰富的交互功能，完全满足甲方现场演示和后期分析的需求。