Imagery Layers Texture Filters

<!--
  示例：影像纹理过滤
  说明：左半边线性过滤、右半边最近邻，放大看瓦片像素的边缘差别
  核心逻辑：minificationFilter / magnificationFilter = NEAREST → splitDirection 对照
  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>影像纹理过滤</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">左半边是默认线性过滤，右半边是最近邻，放大后像素块很明显。</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 makeGridImage() {
    var c = document.createElement('canvas');
    c.width = 256; c.height = 256;
    var ctx = c.getContext('2d');
    for (var y = 0; y < 256; y += 32) {
      for (var x = 0; x < 256; x += 32) {
        var on = ((x / 32) + (y / 32)) % 2 === 0;
        ctx.fillStyle = on ? '#3f6f9c' : '#d9c27a';
        ctx.fillRect(x, y, 32, 32);
      }
    }
    return c.toDataURL('image/png');
  }

  var rect = Cesium.Rectangle.fromDegrees(115.9, 39.5, 116.9, 40.2);
  var url = makeGridImage();

  var left = viewer.imageryLayers.addImageryProvider(
    new Cesium.SingleTileImageryProvider({ url: url, rectangle: rect })
  );
  left.splitDirection = Cesium.SplitDirection.LEFT;

  var right = viewer.imageryLayers.addImageryProvider(
    new Cesium.SingleTileImageryProvider({ url: url, rectangle: rect })
  );
  right.splitDirection = Cesium.SplitDirection.RIGHT;

  /* 默认是 LINEAR，改成 NEAREST 后像素边界变硬 */
  right.minificationFilter = Cesium.TextureMinificationFilter.NEAREST;
  right.magnificationFilter = Cesium.TextureMagnificationFilter.NEAREST;

  scene.splitPosition = 0.5;
  viewer.camera.flyTo({
    destination: Cesium.Rectangle.fromDegrees(116.2, 39.7, 116.6, 40.0),
    duration: 0
  });
})();
</script>
</body>
</html>