Depth of Field

<!--
  示例：景深后处理
  说明：焦平面之外逐渐虚化，近处盒子清晰、远处一排房子发糊
  核心逻辑：PostProcessStageLibrary.createDepthOfFieldStage() → 改 focalDistance → 低视角摆放前后景
  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>景深后处理</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">focalDistance 是要对焦的距离（米）。前后景拉开，虚化才看得出来。</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;

  if (Cesium.PostProcessStageLibrary.isDepthOfFieldSupported(scene)) {
    var dof = scene.postProcessStages.add(
      Cesium.PostProcessStageLibrary.createDepthOfFieldStage()
    );
    dof.uniforms.focalDistance = 55.0;   /* 对焦 55 米处 */
    dof.uniforms.delta = 1.0;            /* 弥散半径上限 */
    dof.uniforms.sigma = 3.8;            /* 模糊强度 */
    dof.uniforms.stepSize = 2.4;         /* 采样步长 */
  }

  /* 近景一排小盒子 */
  for (var i = 0; i < 10; i++) {
    viewer.entities.add({
      position: Cesium.Cartesian3.fromDegrees(116.3880 + i * 0.0012, 39.9058, 3),
      box: {
        dimensions: new Cesium.Cartesian3(4, 4, 6),
        material: Cesium.Color.fromCssColorString('#6d90c0'),
        outline: true,
        outlineColor: Cesium.Color.fromCssColorString('#0b0f14')
      }
    });
  }
  /* 远景一排高一点的楼 */
  for (var j = 0; j < 12; j++) {
    viewer.entities.add({
      position: Cesium.Cartesian3.fromDegrees(116.3880 + j * 0.0016, 39.9082, 26),
      box: {
        dimensions: new Cesium.Cartesian3(9, 9, 52),
        material: Cesium.Color.fromCssColorString('#4a5d76')
      }
    });
  }
  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3905, 39.9006, 26),
    orientation: { heading: Cesium.Math.toRadians(22), pitch: Cesium.Math.toRadians(-4), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>