Wall Extrude

<!--
  示例：沿山脊拉起一段起伏墙体
  要点：WallGraphics 的 maximumHeights 逐点给出顶高，minimumHeights 压到地面
  依赖：CesiumJS 1.121 · jsDelivr CDN，顶高数组由正弦函数生成
-->
<!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>拉伸墙体</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}
  .hud button{font:inherit;font-size:12px;padding:3px 9px;border-radius:4px;cursor:pointer;
       border:1px solid #343b46;background:#1d232b;color:#cfd6e2}
  .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>起伏墙体</b></div>
  <div class="row">14 个顶点 · 顶高 40~260 米</div>
  <div class="row"><button id="flip">底面转到 120 米</button></div>
  <div class="row" id="info">minimumHeights 全为 0</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;

  var COUNT = 14;
  var START = { lng: 116.368, lat: 39.918 };
  var positions = [];
  var tops = [];
  var bottoms = [];

  for (var i = 0; i < COUNT; i++) {
    var lng = START.lng + i * 0.0022;
    var lat = START.lat + Math.sin(i * 0.72) * 0.0018;
    positions.push(Cesium.Cartesian3.fromDegrees(lng, lat));
    tops.push(150 + 110 * Math.sin(i * 0.55));
    bottoms.push(0);
  }

  var wall = viewer.entities.add({
    wall: {
      positions: positions,
      maximumHeights: tops,
      minimumHeights: bottoms,
      material: Cesium.Color.fromCssColorString('#4d9bff').withAlpha(0.55),
      outline: true,
      outlineColor: Cesium.Color.fromCssColorString('#cfe4ff'),
      outlineWidth: 1.5
    }
  });

  /* 墙脚下的地面辅助线，方便看墙的水平走向 */
  viewer.entities.add({
    polyline: {
      positions: positions,
      width: 2,
      material: Cesium.Color.fromCssColorString('#5f6b7d'),
      clampToGround: true
    }
  });

  /* 墙顶描边，用一条贴墙顶的折线强调起伏 */
  var topPositions = [];
  for (var j = 0; j < COUNT; j++) {
    var c = positions[j];
    var carto = Cesium.Cartographic.fromCartesian(c);
    topPositions.push(Cesium.Cartesian3.fromRadians(carto.longitude, carto.latitude, tops[j]));
  }
  viewer.entities.add({
    polyline: { positions: topPositions, width: 1.5, material: Cesium.Color.fromCssColorString('#ffd18a') }
  });

  var raised = false;
  document.getElementById('flip').addEventListener('click', function () {
    raised = !raised;
    var v = raised ? 120 : 0;
    wall.wall.minimumHeights = new Array(COUNT).fill(v);
    document.getElementById('info').textContent = raised
      ? 'minimumHeights 抬到 120 米，墙悬空' : 'minimumHeights 全为 0';
    this.textContent = raised ? '底面压回 0 米' : '底面转到 120 米';
  });

  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.372, 39.905, 3600),
    orientation: {
      heading: Cesium.Math.toRadians(35),
      pitch: Cesium.Math.toRadians(-22),
      roll: 0
    },
    duration: 0
  });
})();
</script>
</body>
</html>