mirror of
https://github.com/jiawanlong/Cesium-Examples.git
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115 lines
3.9 KiB
HTML
115 lines
3.9 KiB
HTML
<!--********************************************************************
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* by jiawanlong
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*********************************************************************-->
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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="UTF-8" />
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<link rel="stylesheet" href="./../../libs/cesium/Cesium1.98/Widgets/widgets.css" />
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<script type="text/javascript" src="./../../libs/cesium/Cesium1.98/Cesium.js"></script>
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<script src="./turf.min.js"></script>
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</head>
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<body style="
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margin: 0;
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overflow: hidden;
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background: #fff;
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width: 100%;
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height: 100%;
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position: absolute;
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top: 0;
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">
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<div id="map" style="margin: 0 auto; width: 100%; height: 100%"></div>
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<script type="text/javascript">
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Cesium.Ion.defaultAccessToken =
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"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJqdGkiOiI3ZjQ5ZGUzNC1jNWYwLTQ1ZTMtYmNjYS05YTY4ZTVmN2I2MDkiLCJpZCI6MTE3MTM4LCJpYXQiOjE2NzY0NDUyODB9.ZaNSBIfc1sGLhQd_xqhiSsc0yr8oS0wt1hAo9gbke6M";
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const viewer = new Cesium.Viewer("map");
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viewer.camera.flyTo({
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destination: new Cesium.Cartesian3(-930635.3822360804, -5464034.592507356, 3161315.472199566),
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orientation: {
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heading: 6.126725323385694, // east, default value is 0.0 (north)
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pitch: -0.22764983413485584, // default value (looking down)
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roll: 6.28290552999833 // default value
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}
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});
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let obj = {
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minx: -100,
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miny: 30,
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maxx: -99.5,
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maxy: 30.5,
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dx: 15, // 雨滴宽度
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ds: 5000, // 雨滴数量
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sd: 50, // 雨滴下落速度
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};
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// 创建一个 BillboardCollection 来存储所有的雨滴
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let billboardCollection = viewer.scene.primitives.add(new Cesium.BillboardCollection());
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let rainDrops = [];
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// 添加雨滴并开始更新
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addRain();
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function addRain() {
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// 通过 Turf 生成随机的雨滴位置
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let points = turf.randomPoint(obj.ds, { bbox: [obj.minx, obj.miny, obj.maxx, obj.maxy] });
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points.features.forEach((feature) => {
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let cor = feature.geometry.coordinates;
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let billboard = billboardCollection.add({
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scaleByDistance: new Cesium.NearFarScalar(2000000, 0.8, 8000000, 0.3),
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position: Cesium.Cartesian3.fromDegrees(cor[0], cor[1], getRandomHeight()),
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image: './yd.jpg',
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width: obj.dx,
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height: obj.dx,
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});
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rainDrops.push(billboard);
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});
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// 使用请求动画帧来优化性能
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viewer.scene.postRender.addEventListener(updateRainPositions);
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}
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// 获取一个随机的雨滴高度
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function getRandomHeight() {
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return Math.floor(Math.random() * (10000 - 1000 + 1)) + 1000;
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}
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// 更新所有雨滴的位置
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function updateRainPositions() {
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rainDrops.forEach(billboard => {
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updateBillboardPosition(billboard);
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});
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}
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// 更新雨滴的高度
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function updateBillboardPosition(billboard) {
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var ellipsoid = viewer.scene.globe.ellipsoid;
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var cartographic = ellipsoid.cartesianToCartographic(billboard.position);
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var lat = Cesium.Math.toDegrees(cartographic.latitude);
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var lng = Cesium.Math.toDegrees(cartographic.longitude);
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var height = cartographic.height;
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// 如果高度小于0，则重新设置为随机高度
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if (height < 0) {
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height = getRandomHeight();
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} else {
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// 向下移动雨滴
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height -= obj.sd;
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}
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// 更新雨滴的位置
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billboard.position = Cesium.Cartesian3.fromDegrees(lng, lat, height);
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}
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</script>
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</body>
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</html> |