Cardboard

<!--
  示例：打开 VR 按钮，把场景切到可分屏的立体模式
  说明：Viewer 的 vrButton 打开后右下角出现 VR 按钮，场景由一圈立柱和一个地面体块组成
  核心逻辑：vrButton: true + 关闭球体 + BoxGeometry 立柱，相机站在场景里
  依赖：CesiumJS 1.121 · jsDelivr CDN，几何体由代码构造
-->
<!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>立体眼镜模式</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}
  .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>VR 按钮</b></div>
  <div>右下角有 VR 按钮，点击进入全屏立体渲染</div>
  <div>没有头显时浏览器会拒绝进入，属于设备限制</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,
    vrButton: true,
    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.backgroundColor = Cesium.Color.fromCssColorString('#070b10');
  scene.globe.show = false;
  scene.skyBox.show = false;
  scene.sun.show = false;
  scene.moon.show = false;
  if (scene.skyAtmosphere) scene.skyAtmosphere.show = false;

  var CENTER_LON = 116.3913;
  var CENTER_LAT = 39.9074;
  var CENTER = Cesium.Cartesian3.fromDegrees(CENTER_LON, CENTER_LAT, 0);

  function boxInstance(lon, lat, w, h, d, color, baseHeight) {
    var geometry = new Cesium.BoxGeometry({
      vertexFormat: Cesium.PerInstanceColorAppearance.VERTEX_FORMAT,
      minimumCorner: new Cesium.Cartesian3(-w / 2, -d / 2, 0),
      maximumCorner: new Cesium.Cartesian3(w / 2, d / 2, h)
    });

    return new Cesium.GeometryInstance({
      geometry: geometry,
      modelMatrix: Cesium.Transforms.eastNorthUpToFixedFrame(
        Cesium.Cartesian3.fromDegrees(lon, lat, baseHeight || 0)
      ),
      attributes: {
        color: Cesium.ColorGeometryInstanceAttribute.fromColor(color)
      }
    });
  }

  var instances = [];

  /* 地面：一块很薄的体块 */
  instances.push(boxInstance(CENTER_LON, CENTER_LAT, 120, 0.3, 120,
    Cesium.Color.fromCssColorString('#2a3440'), 0));

  /* 一圈立柱，近处三根、远处四根，形成明显视差 */
  var colors = ['#4d9bff', '#39c0a0', '#f2a03d', '#e45c7a', '#8e7cf0', '#3fb6e8', '#d8d3c8'];
  for (var i = 0; i < 7; i++) {
    var ang = (i / 7) * Math.PI * 2;
    var r = 22 + (i % 3) * 12;
    instances.push(boxInstance(
      CENTER_LON + r * Math.cos(ang) * 1e-5 / 0.85,
      CENTER_LAT + r * Math.sin(ang) * 1e-5,
      3 + (i % 3), 14 + i * 4, 3 + (i % 3),
      Cesium.Color.fromCssColorString(colors[i]), 1
    ));
  }

  scene.primitives.add(new Cesium.Primitive({
    geometryInstances: instances,
    appearance: new Cesium.PerInstanceColorAppearance({ flat: false, translucent: false }),
    asynchronous: false
  }));

  /* 相机站在地面上，略高于人眼 */
  var eye = Cesium.Cartesian3.fromDegrees(CENTER_LON - 0.00018, CENTER_LAT - 0.00028, 1.7);
  viewer.camera.lookAt(
    eye,
    new Cesium.HeadingPitchRange(0, Cesium.Math.toRadians(-4), 0)
  );
  viewer.camera.lookAtTransform(Cesium.Matrix4.IDENTITY);
})();
</script>
</body>
</html>