仿真 3D 图块采用 OGC 标准 glTF 格式,这意味着您可以使用支持 OGC 3D 图块规范的任何渲染程序来构建 3D 可视化内容。例如,Cesium 是一个用于渲染 3D 可视化的基本开源库。
使用 CesiumJS
CesiumJS 是一个用于在 Web 上进行 3D 可视化的开源 JavaScript 库。如需详细了解如何使用 CesiumJS,请参阅了解 CesiumJS。
用户控制功能
CesiumJS 图块渲染程序具有一组标准的用户控件。
操作 | 说明 |
---|---|
平移视图 | 点击左键并拖动 |
缩放视图 | 右键点击并拖动,或滚动鼠标滚轮 |
旋转视图 | Ctrl + 左键/右键点击并拖动,或中键点击并拖动 |
最佳做法
您可以通过多种方法缩短 CesiumJS 3D 加载时间。例如:
将以下语句添加到呈现的 HTML 中,以启用并发请求:
Cesium.RequestScheduler.requestsByServer["tile.googleapis.com:443"] = <REQUEST_COUNT>
REQUEST_COUNT
越高,功能块的加载速度就越快。不过,如果在REQUEST_COUNT
大于 10 且缓存已停用的 Chrome 浏览器中加载,您可能会遇到已知的 Chrome 问题。对于大多数使用情形,我们建议将REQUEST_COUNT
设为 18,以实现最佳性能。启用跳过详细级别。如需了解详情,请参阅此 Cesium 问题。
请启用 showCreditsOnScreen: true
,确保正确显示数据归因。如需了解详情,请参阅政策。
呈现指标
如需查找帧速率,请查看 requestAnimationFrame 方法每秒被调用的次数。
如需了解帧延迟时间的计算方式,请查看 PerformanceDisplay 类。
CesiumJS 渲染程序示例
只需提供根图块集网址,即可将 CesiumJS 渲染程序与 Map Tiles API 的 3D 图块搭配使用。
简单示例
以下示例会初始化 CesiumJS 渲染程序,然后加载根图块集。
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<title>CesiumJS 3D Tiles Simple Demo</title>
<script src="https://ajax.googleapis.com/ajax/libs/cesiumjs/1.105/Build/Cesium/Cesium.js"></script>
<link href="https://ajax.googleapis.com/ajax/libs/cesiumjs/1.105/Build/Cesium/Widgets/widgets.css" rel="stylesheet">
</head>
<body>
<div id="cesiumContainer"></div>
<script>
// Enable simultaneous requests.
Cesium.RequestScheduler.requestsByServer["tile.googleapis.com:443"] = 18;
// Create the viewer.
const viewer = new Cesium.Viewer('cesiumContainer', {
imageryProvider: false,
baseLayerPicker: false,
geocoder: false,
globe: false,
// https://cesium.com/blog/2018/01/24/cesium-scene-rendering-performance/#enabling-request-render-mode
requestRenderMode: true,
});
// Add 3D Tiles tileset.
const tileset = viewer.scene.primitives.add(new Cesium.Cesium3DTileset({
url: "https://tile.googleapis.com/v1/3dtiles/root.json?key=YOUR_API_KEY",
// This property is needed to appropriately display attributions
// as required.
showCreditsOnScreen: true,
}));
</script>
</body>
如需了解 requestRenderMode
,请参阅启用请求呈现模式。
HTML 页面将呈现如下所示。
Places API 集成
您可以将 CesiumJS 与 Places API 搭配使用,以检索更多信息。您可以使用自动补全 widget 快速跳转到“地点”的视口。此示例使用了地点自动补全 API(可通过按照这些说明进行启用)和 Maps JavaScript API(可通过按照这些说明进行启用)。
<!DOCTYPE html>
<head>
<meta charset="utf-8" />
<title>CesiumJS 3D Tiles Places API Integration Demo</title>
<script src="https://ajax.googleapis.com/ajax/libs/cesiumjs/1.105/Build/Cesium/Cesium.js"></script>
<link href="https://ajax.googleapis.com/ajax/libs/cesiumjs/1.105/Build/Cesium/Widgets/widgets.css" rel="stylesheet">
</head>
<body>
<label for="pacViewPlace">Go to a place: </label>
<input
type="text"
id="pacViewPlace"
name="pacViewPlace"
placeholder="Enter a location..."
style="width: 300px"
/>
<div id="cesiumContainer"></div>
<script>
// Enable simultaneous requests.
Cesium.RequestScheduler.requestsByServer["tile.googleapis.com:443"] = 18;
// Create the viewer.
const viewer = new Cesium.Viewer("cesiumContainer", {
imageryProvider: false,
baseLayerPicker: false,
requestRenderMode: true,
geocoder: false,
globe: false,
});
// Add 3D Tiles tileset.
const tileset = viewer.scene.primitives.add(
new Cesium.Cesium3DTileset({
url: "https://tile.googleapis.com/v1/3dtiles/root.json?key=YOUR_API_KEY",
// This property is required to display attributions as required.
showCreditsOnScreen: true,
})
);
const zoomToViewport = (viewport) => {
viewer.entities.add({
polyline: {
positions: Cesium.Cartesian3.fromDegreesArray([
viewport.getNorthEast().lng(), viewport.getNorthEast().lat(),
viewport.getSouthWest().lng(), viewport.getNorthEast().lat(),
viewport.getSouthWest().lng(), viewport.getSouthWest().lat(),
viewport.getNorthEast().lng(), viewport.getSouthWest().lat(),
viewport.getNorthEast().lng(), viewport.getNorthEast().lat(),
]),
width: 10,
clampToGround: true,
material: Cesium.Color.RED,
},
});
viewer.flyTo(viewer.entities);
};
function initAutocomplete() {
const autocomplete = new google.maps.places.Autocomplete(
document.getElementById("pacViewPlace"),
{
fields: [
"geometry",
"name",
],
}
);
autocomplete.addListener("place_changed", () => {
viewer.entities.removeAll();
const place = autocomplete.getPlace();
if (!place.geometry || !place.geometry.viewport) {
window.alert("No viewport for input: " + place.name);
return;
}
zoomToViewport(place.geometry.viewport);
});
}
</script>
<script
async=""
src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=places&callback=initAutocomplete"
></script>
</body>
旋转的无人机视图
您可以控制摄像头,以动画形式浏览图块集。将此动画与 Places API 和 Elevation API 结合使用时,可模拟任何地图注点的交互式无人机航拍。
此代码示例会让您围绕您在 Autocomplete widget 中选择的地点飞行。
<!DOCTYPE html>
<head>
<meta charset="utf-8" />
<title>CesiumJS 3D Tiles Rotating Drone View Demo</title>
<script src="https://ajax.googleapis.com/ajax/libs/cesiumjs/1.105/Build/Cesium/Cesium.js"></script>
<link href="https://ajax.googleapis.com/ajax/libs/cesiumjs/1.105/Build/Cesium/Widgets/widgets.css" rel="stylesheet">
</head>
<body>
<label for="pacViewPlace">Go to a place: </label>
<input type="text" id="pacViewPlace" name="pacViewPlace" placeholder="Enter a location..." style="width: 300px" />
<div id="cesiumContainer"></div>
<script>
// Enable simultaneous requests.
Cesium.RequestScheduler.requestsByServer["tile.googleapis.com:443"] = 18;
// Create the viewer and remove unneeded options.
const viewer = new Cesium.Viewer("cesiumContainer", {
imageryProvider: false,
baseLayerPicker: false,
homeButton: false,
fullscreenButton: false,
navigationHelpButton: false,
vrButton: false,
sceneModePicker: false,
geocoder: false,
globe: false,
infobox: false,
selectionIndicator: false,
timeline: false,
projectionPicker: false,
clockViewModel: null,
animation: false,
requestRenderMode: true,
});
// Add 3D Tile set.
const tileset = viewer.scene.primitives.add(
new Cesium.Cesium3DTileset({
url: "https://tile.googleapis.com/v1/3dtiles/root.json?key=YOUR_API_KEY",
// This property is required to display attributions.
showCreditsOnScreen: true,
})
);
// Point the camera at a location and elevation, at a viewport-appropriate distance.
function pointCameraAt(location, viewport, elevation) {
const distance = Cesium.Cartesian3.distance(
Cesium.Cartesian3.fromDegrees(
viewport.getSouthWest().lng(), viewport.getSouthWest().lat(), elevation),
Cesium.Cartesian3.fromDegrees(
viewport.getNorthEast().lng(), viewport.getNorthEast().lat(), elevation)
) / 2;
const target = new Cesium.Cartesian3.fromDegrees(location.lng(), location.lat(), elevation);
const pitch = -Math.PI / 4;
const heading = 0;
viewer.camera.lookAt(target, new Cesium.HeadingPitchRange(heading, pitch, distance));
}
// Rotate the camera around a location and elevation, at a viewport-appropriate distance.
let unsubscribe = null;
function rotateCameraAround(location, viewport, elevation) {
if(unsubscribe) unsubscribe();
pointCameraAt(location, viewport, elevation);
unsubscribe = viewer.clock.onTick.addEventListener(() => {
viewer.camera.rotate(Cesium.Cartesian3.UNIT_Z);
});
}
function initAutocomplete() {
const autocomplete = new google.maps.places.Autocomplete(
document.getElementById("pacViewPlace"), {
fields: [
"geometry",
"name",
],
}
);
autocomplete.addListener("place_changed", async () => {
const place = autocomplete.getPlace();
if (!(place.geometry && place.geometry.viewport && place.geometry.location)) {
window.alert(`Insufficient geometry data for place: ${place.name}`);
return;
}
// Get place elevation using the ElevationService.
const elevatorService = new google.maps.ElevationService();
const elevationResponse = await elevatorService.getElevationForLocations({
locations: [place.geometry.location],
});
if(!(elevationResponse.results && elevationResponse.results.length)){
window.alert(`Insufficient elevation data for place: ${place.name}`);
return;
}
const elevation = elevationResponse.results[0].elevation || 10;
rotateCameraAround(
place.geometry.location,
place.geometry.viewport,
elevation
);
});
}
</script>
<script async src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&libraries=places&callback=initAutocomplete"></script>
</body>
绘制多段线和标签
以下代码示例演示了如何向地图添加多段线和标签。您可以向地图添加多段线,以显示驾车和步行路线,或显示房产边界,或计算驾车和步行时长。您还可以在不实际渲染场景的情况下获取属性。
您可以带领用户游览精选的社区,也可以展示当前正在促销的邻近房源,然后再向场景中添加广告牌等 3D 对象。
您可以总结行程,列出您查看过的房源,并在虚拟对象中显示这些详细信息。
<!DOCTYPE html>
<head>
<meta charset="utf-8" />
<title>CesiumJS 3D Tiles Polyline and Label Demo</title>
<script src="https://ajax.googleapis.com/ajax/libs/cesiumjs/1.105/Build/Cesium/Cesium.js"></script>
<link
href="https://ajax.googleapis.com/ajax/libs/cesiumjs/1.105/Build/Cesium/Widgets/widgets.css"
rel="stylesheet"
/>
</head>
<body>
<div id="cesiumContainer"></div>
<script>
// Enable simultaneous requests.
Cesium.RequestScheduler.requestsByServer["tile.googleapis.com:443"] = 18;
// Create the viewer.
const viewer = new Cesium.Viewer("cesiumContainer", {
imageryProvider: false,
baseLayerPicker: false,
requestRenderMode: true,
geocoder: false,
globe: false,
});
// Add 3D Tiles tileset.
const tileset = viewer.scene.primitives.add(
new Cesium.Cesium3DTileset({
url: "https://tile.googleapis.com/v1/3dtiles/root.json?key=YOUR_API_KEY",
// This property is required to display attributions as required.
showCreditsOnScreen: true,
})
);
// Draws a circle at the position, and a line from the previous position.
const drawPointAndLine = (position, prevPosition) => {
viewer.entities.removeAll();
if (prevPosition) {
viewer.entities.add({
polyline: {
positions: [prevPosition, position],
width: 3,
material: Cesium.Color.WHITE,
clampToGround: true,
classificationType: Cesium.ClassificationType.CESIUM_3D_TILE,
},
});
}
viewer.entities.add({
position: position,
ellipsoid: {
radii: new Cesium.Cartesian3(1, 1, 1),
material: Cesium.Color.RED,
},
});
};
// Compute, draw, and display the position's height relative to the previous position.
var prevPosition;
const processHeights = (newPosition) => {
drawPointAndLine(newPosition, prevPosition);
const newHeight = Cesium.Cartographic.fromCartesian(newPosition).height;
let labelText = "Current altitude (meters above sea level):\n\t" + newHeight;
if (prevPosition) {
const prevHeight =
Cesium.Cartographic.fromCartesian(prevPosition).height;
labelText += "\nHeight from previous point (meters):\n\t" + Math.abs(newHeight - prevHeight);
}
viewer.entities.add({
position: newPosition,
label: {
text: labelText,
disableDepthTestDistance: Number.POSITIVE_INFINITY,
pixelOffset: new Cesium.Cartesian2(0, -10),
showBackground: true,
verticalOrigin: Cesium.VerticalOrigin.BOTTOM,
}
});
prevPosition = newPosition;
};
const handler = new Cesium.ScreenSpaceEventHandler(viewer.canvas);
handler.setInputAction(function (event) {
const earthPosition = viewer.scene.pickPosition(event.position);
if (Cesium.defined(earthPosition)) {
processHeights(earthPosition);
}
}, Cesium.ScreenSpaceEventType.LEFT_CLICK);
</script>
</body>
相机轨道
在 Cesium 中,您可以让摄像头围绕地图注点旋转,避免与建筑物相撞。或者,您也可以在相机穿过建筑物时使建筑物透明。
首先,将摄像头锁定到一个点,然后您可以创建摄像头轨道来展示您的素材资源。为此,您可以将相机的 lookAtTransform
函数与事件监听器搭配使用,如此代码示例所示。
// Lock the camera onto a point.
const center = Cesium.Cartesian3.fromRadians(
2.4213211833389243,
0.6171926869414084,
3626.0426275055174
);
const transform = Cesium.Transforms.eastNorthUpToFixedFrame(center);
viewer.scene.camera.lookAtTransform(
transform,
new Cesium.HeadingPitchRange(0, -Math.PI / 8, 2900)
);
// Orbit around this point.
viewer.clock.onTick.addEventListener(function (clock) {
viewer.scene.camera.rotateRight(0.005);
});
如需详细了解如何控制摄像头,请参阅控制摄像头
使用 Cesium for Unreal
如需将 Cesium for Unreal 插件与 3D 图块 API 搭配使用,请按以下步骤操作。
安装 Cesium for Unreal 插件。
创建一个新的 Unreal 项目。
连接到 Google 仿真 3D 图块 API。
从菜单中依次选择 Cesium > Cesium,打开 Cesium 窗口。
选择空白 3D 图块图集。
在世界轮廓图中,选择此 Cesium3DTileset 以打开详细信息面板。
将来源从通过铯离子更改为通过网址。
将网址设置为 Google 3D 图块网址。
https://tile.googleapis.com/v1/3dtiles/root.json?key=YOUR_API_KEY
- 启用在屏幕上显示制作人员名单,以正确显示制作人员名单。
这会加载世界。如需移动到任何经纬度,请在大纲面板中选择 CesiumGeoreference 项,然后在详细信息面板中修改起点经纬度/高度。
使用 Cesium for Unity
如需将逼真的图块与适用于 Unity 的 Cesium 搭配使用,请按以下步骤操作。
创建一个新的 Unity 项目。
在“Package Manager”(软件包管理器)部分中添加新的 Scoped Registry(通过 Editor > Project Settings)。
名称:Cesium
网址:https://unity.pkg.cesium.com
范围:com.cesium.unity
安装 Cesium for Unity 软件包。
连接到 Google 仿真 3D 图块 API。
从菜单中依次选择 Cesium > Cesium,打开 Cesium 窗口。
点击空白 3D 图块图集。
在左侧面板的来源下,选择图块集来源选项中的从网址(而不是“从 Cesium Ion”)。
将网址设置为 Google 3D 图块网址。
https://tile.googleapis.com/v1/3dtiles/root.json?key=YOUR_API_KEY
- 启用在屏幕上显示制作人员名单,以正确显示制作人员名单。
这会加载世界。如需移动到任何 LatLng,请在 Scene Hierarchy 中选择 CesiumGeoreference 项,然后在 Inspector 中修改“Origin Latitude/Longitude/Height”。
使用 deck.gl
deck.gl 由 WebGL 提供支持,是一个用于实现高性能、大规模数据可视化的开源 JavaScript 框架。
归因
请从图块 gltf asset
中提取 copyright
字段,然后在渲染的视图中显示该字段,以确保正确显示数据归因。如需了解详情,请参阅显示数据归因。
deck.gl 渲染程序示例
简单示例
以下示例会初始化 deck.gl 渲染程序,然后以 3D 方式加载地点。在代码中,请务必将 YOUR_API_KEY 替换为您的实际 API 密钥。
<!DOCTYPE html>
<html>
<head>
<title>deck.gl Photorealistic 3D Tiles example</title>
<script src="https://unpkg.com/deck.gl@latest/dist.min.js"></script>
<style>
body { margin: 0; padding: 0;}
#map { position: absolute; top: 0;bottom: 0;width: 100%;}
#credits { position: absolute; bottom: 0; right: 0; padding: 2px; font-size: 15px; color: white;
text-shadow: -1px 0 black, 0 1px black, 1px 0 black, 0 -1px black;}
</style>
</head>
<body>
<div id="map"></div>
<div id="credits"></div>
<script>
const GOOGLE_API_KEY = YOUR_API_KEY;
const TILESET_URL = `https://tile.googleapis.com/v1/3dtiles/root.json`;
const creditsElement = document.getElementById('credits');
new deck.DeckGL({
container: 'map',
initialViewState: {
latitude: 50.0890,
longitude: 14.4196,
zoom: 16,
bearing: 90,
pitch: 60,
height: 200
},
controller: {minZoom: 8},
layers: [
new deck.Tile3DLayer({
id: 'google-3d-tiles',
data: TILESET_URL,
loadOptions: {
fetch: {
headers: {
'X-GOOG-API-KEY': GOOGLE_API_KEY
}
}
},
onTilesetLoad: tileset3d => {
tileset3d.options.onTraversalComplete = selectedTiles => {
const credits = new Set();
selectedTiles.forEach(tile => {
const {copyright} = tile.content.gltf.asset;
copyright.split(';').forEach(credits.add, credits);
creditsElement.innerHTML = [...credits].join('; ');
});
return selectedTiles;
}
}
})
]
});
</script>
</body>
</html>
在 Google 仿真 3D 图块上直观呈现 2D 图层
deck.gl TerrainExtension 可将原本的 2D 数据渲染到 3D 表面。例如,您可以将建筑物平面图的 GeoJSON 叠加在仿真 3D 图块几何图形上。
在以下示例中,建筑物图层使用适应 Photorealistic 3D 图块 Surface 的多边形进行可视化。
<!DOCTYPE html>
<html>
<head>
<title>Google 3D tiles example</title>
<script src="https://unpkg.com/deck.gl@latest/dist.min.js"></script>
<style>
body { margin: 0; padding: 0;}
#map { position: absolute; top: 0;bottom: 0;width: 100%;}
#credits { position: absolute; bottom: 0; right: 0; padding: 2px; font-size: 15px; color: white;
text-shadow: -1px 0 black, 0 1px black, 1px 0 black, 0 -1px black;}
</style>
</head>
<body>
<div id="map"></div>
<div id="credits"></div>
<script>
const GOOGLE_API_KEY = YOUR_API_KEY;
const TILESET_URL = `https://tile.googleapis.com/v1/3dtiles/root.json`;
const BUILDINGS_URL = 'https://raw.githubusercontent.com/visgl/deck.gl-data/master/examples/google-3d-tiles/buildings.geojson'
const creditsElement = document.getElementById('credits');
const deckgl = new deck.DeckGL({
container: 'map',
initialViewState: {
latitude: 50.0890,
longitude: 14.4196,
zoom: 16,
bearing: 90,
pitch: 60,
height: 200
},
controller: true,
layers: [
new deck.Tile3DLayer({
id: 'google-3d-tiles',
data: TILESET_URL,
loadOptions: {
fetch: {
headers: {
'X-GOOG-API-KEY': GOOGLE_API_KEY
}
}
},
onTilesetLoad: tileset3d => {
tileset3d.options.onTraversalComplete = selectedTiles => {
const credits = new Set();
selectedTiles.forEach(tile => {
const {copyright} = tile.content.gltf.asset;
copyright.split(';').forEach(credits.add, credits);
creditsElement.innerHTML = [...credits].join('; ');
});
return selectedTiles;
}
},
operation: 'terrain+draw'
}),
new deck.GeoJsonLayer({
id: 'buildings',
// This dataset is created by CARTO, using other Open Datasets available. More info at: https://3dtiles.carto.com/#about.
data: 'https://raw.githubusercontent.com/visgl/deck.gl-data/master/examples/google-3d-tiles/buildings.geojson',
stroked: false,
filled: true,
getFillColor: ({properties}) => {
const {tpp} = properties;
// quantiles break
if (tpp < 0.6249)
return [254, 246, 181]
else if (tpp < 0.6780)
return [255, 194, 133]
else if (tpp < 0.8594)
return [250, 138, 118]
return [225, 83, 131]
},
opacity: 0.2,
extensions: [new deck._TerrainExtension()]
})
]
});
</script>
</body>
</html>