Particle System Fireworks

<!--
  示例：烟花粒子
  说明：点击地面任意位置，在落点上方炸开一朵彩色烟花
  核心逻辑：ParticleSystem + SphereEmitter + bursts → 点击时在落点创建
  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>烟花粒子</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">每次点击都会在落点上方生成一朵烟花，颜色随机。</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;

  function spark() {
    var c = document.createElement('canvas');
    c.width = c.height = 32;
    var ctx = c.getContext('2d');
    var g = ctx.createRadialGradient(16, 16, 0, 16, 16, 16);
    g.addColorStop(0, 'rgba(255,255,255,1)');
    g.addColorStop(0.35, 'rgba(255,224,150,0.9)');
    g.addColorStop(1, 'rgba(255,180,80,0)');
    ctx.fillStyle = g;
    ctx.fillRect(0, 0, 32, 32);
    return c.toDataURL('image/png');
  }

  var image = spark();

  function burst(position, hue) {
    scene.primitives.add(new Cesium.ParticleSystem({
      image: image,
      startColor: Cesium.Color.fromHsl(hue, 0.85, 0.65, 0.95),
      endColor: Cesium.Color.fromHsl(hue + 0.08, 0.9, 0.45, 0.0),
      startScale: 1.1,
      endScale: 0.2,
      minimumParticleLife: 1.2,
      maximumParticleLife: 2.0,
      minimumSpeed: 24,
      maximumSpeed: 42,
      minimumMass: 0.6,
      maximumMass: 1.1,
      emitter: new Cesium.SphereEmitter(0.6),
      modelMatrix: Cesium.Matrix4.fromTranslation(position),
      lifetime: 2.2,
      bursts: [{ time: 0.0, minimum: 120, maximum: 160 }],
      gravity: new Cesium.Cartesian3(0, 0, -9.8)
    }));
  }

  var handler = new Cesium.ScreenSpaceEventHandler(scene.canvas);
  handler.setInputAction(function (click) {
    var ground = viewer.camera.pickEllipsoid(click.position, Cesium.Ellipsoid.WGS84);
    if (!Cesium.defined(ground)) return;
    var carto = Cesium.Cartographic.fromCartesian(ground);
    var position = Cesium.Cartesian3.fromRadians(carto.longitude, carto.latitude, 120);
    burst(position, Math.random());
  }, Cesium.ScreenSpaceEventType.LEFT_CLICK);

  /* 开场先放一朵，避免空场景 */
  burst(Cesium.Cartesian3.fromDegrees(116.3895, 39.9035, 120), 0.08);
  viewer.camera.flyTo({
    destination: Cesium.Cartesian3.fromDegrees(116.3905, 39.8985, 320),
    orientation: { heading: Cesium.Math.toRadians(-8), pitch: Cesium.Math.toRadians(-10), roll: 0 },
    duration: 0
  });
})();
</script>
</body>
</html>