const viewer = new Cesium.Viewer("cesiumContainer");
//1.计算屏幕坐标
let position = Cesium.Cartesian3.fromDegrees(-60, 30, 0);
let chanedc = Cesium.SceneTransforms.wgs84ToWindowCoordinates(viewer.scene, position);
console.log(chanedc)
//2.判断当前视角是否可见
let cameraOccluder = new Cesium.EllipsoidalOccluder(Cesium.Ellipsoid.WGS84, viewer.camera.position);
let viewerVisible = cameraOccluder.isPointVisible(position);
console.log(viewerVisible)