Geometry and Appearances

<!--
  示例：几何与外观
  说明：用 GeometryInstance 加 Primitive 直接构建三个球体，颜色逐实例指定
  核心逻辑：GeometryInstance + EllipsoidGeometry → PerInstanceColorAppearance → Primitive
  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>几何与外观</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">底层图元不走 Entity，颜色通过实例属性给，适合批量几何。</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;

  function ball(lon, lat, color) {
    var center = Cesium.Cartesian3.fromDegrees(lon, lat, 80);
    return new Cesium.GeometryInstance({
      geometry: new Cesium.EllipsoidGeometry({
        radii: new Cesium.Cartesian3(45, 45, 45),
        vertexFormat: Cesium.PerInstanceColorAppearance.VERTEX_FORMAT
      }),
      modelMatrix: Cesium.Transforms.eastNorthUpToFixedFrame(center),
      attributes: {
        color: Cesium.ColorGeometryInstanceAttribute.fromColor(
          Cesium.Color.fromCssColorString(color).withAlpha(0.9)
        )
      }
    });
  }

  scene.primitives.add(new Cesium.Primitive({
    geometryInstances: [
      ball(116.3860, 39.9036, '#4d86c8'),
      ball(116.3900, 39.9048, '#5bb08a'),
      ball(116.3940, 39.9036, '#d08a4e')
    ],
    appearance: new Cesium.PerInstanceColorAppearance({
      translucent: true,
      flat: false
    }),
    asynchronous: false
  }));
  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3900, 39.8998, 320),
    orientation: { heading: Cesium.Math.toRadians(0), pitch: Cesium.Math.toRadians(-16), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>