3D Tiles 1.1 Cdb Yemen

<!--
  示例：用 Canvas 贴图复现城市街区（CDB 数据集的替代场景）
  说明：官方 CDB 数据集来自 ion；这里用 Canvas 画出路网与街区贴到地面，再叠一排建筑体块
  核心逻辑：Canvas 绘图 → ImageMaterialProperty → 地面多边形 + 实体盒体建筑
  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>用贴图拼出城市街区</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">地面上的深色方格路网是用 Canvas 画的 512×512 贴图，建筑是代码生成的长方体，全部走本地计算。</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('#141c26');
  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;

  /* ---------- 1. Canvas 画街区贴图 ---------- */
  var cv = document.createElement('canvas');
  cv.width = cv.height = 512;
  var ctx = cv.getContext('2d');

  ctx.fillStyle = '#232a35';
  ctx.fillRect(0, 0, 512, 512);

  var block = 64, gap = 8;
  for (var r = 0; r < 8; r++) {
    for (var c = 0; c < 8; c++) {
      var shade = 34 + ((r * 7 + c * 11) % 26);
      ctx.fillStyle = 'rgb(' + (shade + 6) + ',' + (shade + 12) + ',' + (shade + 20) + ')';
      ctx.fillRect(c * block + gap / 2, r * block + gap / 2, block - gap, block - gap);
    }
  }
  /* 主干道压深色 */
  ctx.fillStyle = '#171d26';
  ctx.fillRect(0, 250, 512, 16);
  ctx.fillRect(250, 0, 16, 512);

  /* ---------- 2. 贴到底面 ---------- */
  var west = 116.3835, south = 39.9010, east = 116.3985, north = 39.9120;

  viewer.entities.add({
    polygon: {
      hierarchy: new Cesium.PolygonHierarchy(Cesium.Cartesian3.fromDegreesArray([
        west, south, east, south, east, north, west, north
      ])),
      height: 0,
      material: new Cesium.ImageMaterialProperty({
        image: cv,
        color: Cesium.Color.WHITE.withAlpha(0.95)
      })
    }
  });

  /* ---------- 3. 建筑体块 ---------- */
  var colors = ['#3f4b5c', '#4b586b', '#56637a', '#384455'];
  var seed = 7;
  function rnd() { seed = (seed * 9301 + 49297) % 233280; return seed / 233280; }

  for (var i = 0; i < 26; i++) {
    var lon = west + 0.0015 + rnd() * (east - west - 0.003);
    var lat = south + 0.0015 + rnd() * (north - south - 0.003);
    var h = 14 + rnd() * 46;
    var w = 22 + rnd() * 26;
    viewer.entities.add({
      position: Cesium.Cartesian3.fromDegrees(lon, lat, h / 2),
      box: {
        dimensions: new Cesium.Cartesian3(w, w, h),
        material: Cesium.Color.fromCssColorString(colors[i % colors.length]),
        outline: true,
        outlineColor: Cesium.Color.fromCssColorString('#0d1117')
      }
    });
  }

  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.383, 39.896, 1750),
    orientation: { heading: Cesium.Math.toRadians(24), pitch: Cesium.Math.toRadians(-32), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>