Time Dynamic Point Cloud

<!--
  示例：时间动态点云
  说明：点云逐帧变化颜色与高度，形成呼吸一样的波动
  核心逻辑：时钟驱动 → PointPrimitiveCollection 逐点改高度与颜色
  依赖：CesiumJS 1.121 · jsDelivr CDN
-->
<!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>时间动态点云</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%}
  .tip{position:absolute;left:12px;top:12px;z-index:5;
       background:rgba(23,28,35,.9);border:1px solid #2a313b;border-radius:6px;
       padding:8px 12px;font-size:12px;color:#a2a9b6;max-width:320px;line-height:1.6}

  .cesium-viewer-bottom .cesium-widget-credits,.cesium-viewer-animationContainer,
  .cesium-viewer-timelineContainer{display:none!important}
</style>
</head>
<body>
<div id="c"></div>
<div class="tip">点的颜色和高度都随时间变化，不是静态点云。</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 lon = 116.3895, lat = 39.9035;
  var DLON = 1.17e-5, DLAT = 8.98e-6;
  var points = scene.primitives.add(new Cesium.PointPrimitiveCollection());
  var grid = [];

  /* 16 × 16 的地面点阵 */
  for (var gx = -8; gx <= 8; gx++) {
    for (var gy = -8; gy <= 8; gy++) {
      var p = points.add({
        position: Cesium.Cartesian3.fromDegrees(lon + gx * 8 * DLON, lat + gy * 8 * DLAT, 0),
        pixelSize: 4,
        color: Cesium.Color.WHITE
      });
      grid.push({ p: p, gx: gx, gy: gy });
    }
  }

  var t = 0;
  scene.preRender.addEventListener(function (s, time) {
    t += 0.016;
    for (var i = 0; i < grid.length; i++) {
      var g = grid[i];
      var h = 20 + 16 * Math.sin(t * 1.4 + g.gx * 0.6 + g.gy * 0.4);
      g.p.position = Cesium.Cartesian3.fromDegrees(
        lon + g.gx * 8 * DLON, lat + g.gy * 8 * DLAT, Math.max(2, h)
      );
      var hue = 0.5 + 0.25 * Math.sin(t * 1.4 + g.gx * 0.3);
      g.p.color = Cesium.Color.fromHsl(hue, 0.6, 0.55);
    }
  });
  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3895, 39.8992, 520),
    orientation: { heading: Cesium.Math.toRadians(0), pitch: Cesium.Math.toRadians(-16), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>