3D Tiles Bounding Box Tests Dev

<!--
  示例：包围盒与坐标轴调试
  说明：建筑外围画出略大的黄色包围盒线框，地面伸出红绿蓝三根轴向线
  核心逻辑：盒体实体 → fill:false 只画线框 → ENU 矩阵换算轴向端点 → 折线绘制
  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>包围盒与坐标轴调试</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">黄色线框是放大 5% 的包围盒，红绿蓝分别是东、北、天三个轴向。线框与模型偏差即包围体误差。</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 w = 30, h = 44, d = 24;
  var origin = Cesium.Cartesian3.fromDegrees(116.391, 39.907, 0);

  /* 建筑本体 */
  viewer.entities.add({
    position: origin,
    box: {
      dimensions: new Cesium.Cartesian3(w, h, d),
      material: Cesium.Color.fromCssColorString('#4a576c')
    }
  });

  /* 包围盒线框：略大于本体，方便看出偏差 */
  var pad = 1.05;
  viewer.entities.add({
    position: Cesium.Cartesian3.fromDegrees(116.391, 39.907, h / 2),
    box: {
      dimensions: new Cesium.Cartesian3(w * pad, h * pad, d * pad),
      fill: false,
      outline: true,
      outlineColor: Cesium.Color.fromCssColorString('#ffd166')
    }
  });

  /* 东北天三轴 */
  var enu = Cesium.Transforms.eastNorthUpToFixedFrame(origin);
  var axisLen = 60;
  [[1, 0, 0, '#ff5c5c'], [0, 1, 0, '#3ecf8e'], [0, 0, 1, '#4d9bff']].forEach(function (ax) {
    var p1 = Cesium.Matrix4.multiplyByPoint(enu, Cesium.Cartesian3.ZERO, new Cesium.Cartesian3());
    var p2 = Cesium.Matrix4.multiplyByPoint(enu,
      new Cesium.Cartesian3(ax[0] * axisLen, ax[1] * axisLen, ax[2] * axisLen), new Cesium.Cartesian3());
    viewer.entities.add({
      polyline: {
        positions: [p1, p2],
        width: 3,
        material: Cesium.Color.fromCssColorString(ax[3])
      }
    });
  });

  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3852, 39.9020, 170),
    orientation: { heading: Cesium.Math.toRadians(30), pitch: Cesium.Math.toRadians(-16), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>