Highway

<!--
  示例：三维公路
  核心逻辑：同一条路径画两次，宽的一层是路面、窄的一层是中心标线
  数据：页面内按起讫点插值生成的四条干线
  依赖：deck.gl 9.0 · 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>三维公路</title>
<style>
  html,body{height:100%;margin:0;background:#0d1117}
  body{display:flex;flex-direction:column;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif;color:#e6e8ec}
  .bar{position:relative;z-index:5;flex:0 0 auto;padding:8px 12px;background:#161b22;border-bottom:1px solid #252c36;
       display:flex;gap:14px;align-items:center;font-size:12px;color:#8b93a1;flex-wrap:wrap}
  .bar b{color:#58a6ff;font-weight:600}
  .bar button{background:#21262d;color:#c9d1d9;border:1px solid #30363d;border-radius:4px;padding:3px 9px;
       font:12px/1.4 inherit;cursor:pointer}
  .bar button:hover{border-color:#58a6ff}
  #cv{flex:1 1 auto;min-height:0;width:100%}
</style>
</head>
<body>
<div class="bar">
  <span>干线 <b id="n">—</b></span>
  <span>采样点 <b id="p">—</b></span>
  <button id="flat">视角复位</button>
  <span>拖拽旋转 · 滚轮缩放</span>
</div>
<canvas id="cv"></canvas>
<script src="https://cdn.jsdelivr.net/npm/deck.gl@9.0.35/dist.min.js"></script>
<script>
(function () {
  'use strict';

  if (typeof deck === 'undefined') {
    document.body.innerHTML =
      '<div style="padding:24px;color:#ff8c74">deck.gl 加载失败，请检查能否访问 cdn.jsdelivr.net</div>';
    return;
  }

  /* 在两点之间生成带弧度的路径，弧度方向由 bend 控制 */
  function makePath(a, b, bend, segs) {
    var out = [];
    var mx = (a[0] + b[0]) / 2;
    var my = (a[1] + b[1]) / 2;
    var dx = b[0] - a[0];
    var dy = b[1] - a[1];
    /* 用垂直方向偏移做二次曲线，模拟公路绕开地形 */
    var cx = mx - dy * bend;
    var cy = my + dx * bend;

    for (var i = 0; i <= segs; i++) {
      var t = i / segs;
      var x = (1 - t) * (1 - t) * a[0] + 2 * (1 - t) * t * cx + t * t * b[0];
      var y = (1 - t) * (1 - t) * a[1] + 2 * (1 - t) * t * cy + t * t * b[1];
      out.push([x, y]);
    }
    return out;
  }

  var trunks = [
    { name: '京沪', a: [116.39, 39.90], b: [121.47, 31.23], bend: 0.10 },
    { name: '京广', a: [116.39, 39.90], b: [113.26, 23.12], bend: -0.14 },
    { name: '沪昆', a: [121.47, 31.23], b: [102.71, 25.04], bend: 0.12 },
    { name: '京哈', a: [116.39, 39.90], b: [126.64, 45.75], bend: -0.08 },
    { name: '连霍', a: [108.94, 34.34], b: [87.61, 43.82], bend: 0.16 }
  ].map(function (t) {
    return {
      name: t.name,
      path: makePath(t.a, t.b, t.bend, 120)
    };
  });

  var totalPoints = trunks.reduce(function (s, t) { return s + t.path.length; }, 0);
  document.getElementById('n').textContent = trunks.length;
  document.getElementById('p').textContent = totalPoints.toLocaleString();

  var deckgl = new deck.Deck({
    canvas: document.getElementById('cv'),
    width: '100%',
    height: '100%',
    initialViewState: {
      longitude: 112,
      latitude: 34,
      zoom: 4,
      pitch: 55,
      bearing: -18,
      maxPitch: 75
    },
    controller: true,
    layers: []
  });

  function buildLayers() {
    return [
      /* 路面：单位用米，缩放时宽度跟着地理尺寸变化 */
      new deck.PathLayer({
        id: 'road-surface',
        data: trunks,
        getPath: function (d) { return d.path; },
        getWidth: 9000,
        widthUnits: 'meters',
        widthMinPixels: 3,
        getColor: [46, 52, 64, 235],
        capRounded: true,
        jointRounded: true,
        pickable: true
      }),
      /* 路肩：稍宽一点的描边，视觉上把公路从背景里拉出来 */
      new deck.PathLayer({
        id: 'road-shoulder',
        data: trunks,
        getPath: function (d) { return d.path; },
        getWidth: 12000,
        widthUnits: 'meters',
        widthMinPixels: 4,
        getColor: [90, 100, 116, 180],
        capRounded: true,
        jointRounded: true
      }),
      /* 中心标线：白色细线，叠在路面上 */
      new deck.PathLayer({
        id: 'road-center',
        data: trunks,
        getPath: function (d) { return d.path; },
        getWidth: 700,
        widthUnits: 'meters',
        widthMinPixels: 1,
        getColor: [235, 240, 248, 210],
        capRounded: true,
        jointRounded: true
      })
    ];
  }

  /* 先画路肩、再画路面、最后画标线，靠数组顺序控制叠放 */
  deckgl.setProps({ layers: buildLayers() });

  document.getElementById('flat').addEventListener('click', function () {
    deckgl.setProps({
      viewState: {
        longitude: 112,
        latitude: 34,
        zoom: 4,
        pitch: 55,
        bearing: -18,
        maxPitch: 75
      }
    });
  });

  deckgl.setProps({
    getTooltip: function (info) {
      if (!info.object) return null;
      return info.object.name + ' 干线';
    }
  });

  window.__deck = deckgl;
})();
</script>
</body>
</html>