Corridor Band

<!--
  示例：沿一条路径铺出走廊带
  要点：CorridorGraphics 以折线为中心向两侧扩展宽度，cornerType 决定拐角形状
  依赖：CesiumJS 1.121 · jsDelivr CDN，路径坐标由代码给出
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>走廊带道路</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Widgets/widgets.css">
<style>
  html,body{height:100%;margin:0}
  body{background:#0e1116;color:#e6e8ec;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif}
  #c{height:100%}
  .hud{position:absolute;left:12px;top:12px;z-index:5;background:rgba(23,28,35,.9);
       border:1px solid #2a313b;border-radius:6px;padding:9px 12px;font-size:12px;
       color:#a2a9b6;max-width:250px}
  .hud b{color:#e6e8ec;font-weight:600}
  .hud .row{margin-top:6px}
  select{font:inherit;font-size:12px;background:#1d232b;color:#cfd6e2;
       border:1px solid #343b46;border-radius:4px;padding:2px 4px;width:100%}
  input[type=range]{width:100%}
  .cesium-viewer-bottom .cesium-widget-credits,.cesium-viewer-animationContainer,
  .cesium-viewer-timelineContainer{display:none!important}
</style>
</head>
<body>
<div id="c"></div>
<div class="hud">
  <div><b>走廊带</b></div>
  <div class="row">宽度 <span id="wVal">130</span> 米</div>
  <div class="row"><input id="width" type="range" min="40" max="360" step="10" value="130"></div>
  <div class="row">拐角</div>
  <div class="row">
    <select id="corner">
      <option value="ROUNDED">ROUNDED 圆角</option>
      <option value="MITERED">MITERED 斜接</option>
      <option value="BEVELED">BEVELED 平切</option>
    </select>
  </div>
</div>
<script src="https://cdn.jsdelivr.net/npm/cesium@1.121.0/Build/Cesium/Cesium.js"></script>
<script>
(function () {
  'use strict';

  var viewer = new Cesium.Viewer('c', {
    baseLayer: false,
    baseLayerPicker: false, geocoder: false, homeButton: false,
    sceneModePicker: false, navigationHelpButton: false,
    animation: false, timeline: false, fullscreenButton: false,
    infoBox: false, selectionIndicator: false
  });

  var scene = viewer.scene;
  scene.globe.baseColor = Cesium.Color.fromCssColorString('#1c2733');
  scene.backgroundColor = Cesium.Color.fromCssColorString('#0e1116');
  scene.skyBox.show = false;
  scene.sun.show = false;
  scene.moon.show = false;
  if (scene.skyAtmosphere) scene.skyAtmosphere.show = false;

  /* 一条带三个拐弯的路径，全部用经纬度表示 */
  var PATH = [
    [116.360, 39.930], [116.372, 39.921], [116.381, 39.913],
    [116.392, 39.915], [116.401, 39.906], [116.413, 39.900],
    [116.425, 39.905]
  ];

  var positions = [];
  PATH.forEach(function (p) {
    positions.push(Cesium.Cartesian3.fromDegrees(p[0], p[1], 0));
  });

  /* 外层：半透明路面 */
  viewer.entities.add({
    corridor: {
      positions: positions,
      width: 300,
      cornerType: Cesium.CornerType.ROUNDED,
      material: Cesium.Color.fromCssColorString('#2d3d50').withAlpha(0.75)
    }
  });

  /* 内层：实际走廊带，宽度与拐角可调 */
  var band = viewer.entities.add({
    corridor: {
      positions: positions,
      width: 130,
      cornerType: Cesium.CornerType.ROUNDED,
      material: Cesium.Color.fromCssColorString('#4d9bff').withAlpha(0.62),
      outline: true,
      outlineColor: Cesium.Color.fromCssColorString('#cfe4ff'),
      height: 1
    }
  });

  /* 中心线 */
  viewer.entities.add({
    polyline: {
      positions: positions,
      width: 2,
      material: new Cesium.PolylineDashMaterialProperty({
        color: Cesium.Color.fromCssColorString('#eaf2ff').withAlpha(0.8),
        dashLength: 16
      }),
      clampToGround: true
    }
  });

  document.getElementById('width').addEventListener('input', function () {
    document.getElementById('wVal').textContent = this.value;
    band.corridor.width = parseInt(this.value, 10);
  });

  document.getElementById('corner').addEventListener('change', function () {
    band.corridor.cornerType = Cesium.CornerType[this.value];
  });

  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.393, 39.906, 7800),
    orientation: {
      heading: Cesium.Math.toRadians(2),
      pitch: Cesium.Math.toRadians(-52),
      roll: 0
    },
    duration: 0
  });
})();
</script>
</body>
</html>