cesium viewer.scene.clampToHeight 方法的副作用？

Question

请问异常原因是什么？

---

复现

cesium 沙盒 "cesium": "1.137.0"

import * as Cesium from "cesium";

const viewer = new Cesium.Viewer("cesiumContainer");

viewer.entities.add({
  polygon: {
    hierarchy: Cesium.Cartesian3.fromDegreesArray([
      -99.0, 30.0, -99.1, 30.05, -99.1, 30.0,
    ]),
    // height:0,  // 明确声明后异常消失
  },
});

viewer.zoomTo(viewer.entities);

setInterval(() => {
  viewer.scene.clampToHeight(Cesium.Cartesian3.fromDegrees(-95.0, 30.0));
}, 100);

Answer 1

如果是要polygon贴地, 建议直接给明确高度 heightReference: Cesium.HeightReference.CLAMP_TO_GROUND;
clampToHeight依赖当前帧的深度纹理,比如地形和其他Primitive的渲染结果,需要检测地形,polygon没有给高度,而且加了setInterval,会不断触发深度计算,导致渲染不稳定;
所以不要频繁调用clampToHeight