Custom Per Feature Post Process

<!--
  示例：逐对象黑白后处理
  说明：鼠标指到哪个楼体，哪个楼体变成黑白，场景其余部分仍是彩色
  核心逻辑：createBlackAndWhiteStage() → selected = [拾取对象] → 拾取为空则全彩
  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>逐对象黑白后处理</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">黑白只作用在鼠标下的对象上。把光标移开盒子就会恢复彩色。</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;

  for (var i = 0; i < 7; i++) {
    viewer.entities.add({
      position: Cesium.Cartesian3.fromDegrees(116.3870 + i * 0.0015, 39.9050 + (i % 2) * 0.0012, 8),
      box: {
        dimensions: new Cesium.Cartesian3(12, 12, 16 + (i % 3) * 8),
        material: Cesium.Color.fromHsl(0.02 + i * 0.13, 0.55, 0.55)
      }
    });
  }

  var bw = scene.postProcessStages.add(
    Cesium.PostProcessStageLibrary.createBlackAndWhiteStage()
  );

  var handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
  handler.setInputAction(function (movement) {
    var picked = scene.pick(movement.endPosition);
    bw.selected = Cesium.defined(picked) && picked.id ? [picked] : [];
  }, Cesium.ScreenSpaceEventType.MOUSE_MOVE);
  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3920, 39.8998, 210),
    orientation: { heading: Cesium.Math.toRadians(8), pitch: Cesium.Math.toRadians(-32), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>