关于3dtiles Interactivity中的zoom方法精简写法

原版本涉及到坐标系变化和矩阵变换，在对原版的思路掌握后，特写一个精简版，帮助大家理解。

function zoom(movement, feature) {
  const longitude = Cesium.Math.toRadians(feature.getProperty("Longitude"));
  const latitude = Cesium.Math.toRadians(feature.getProperty("Latitude"));
  const height = feature.getProperty("Height");

  const positionCartographic = new Cesium.Cartographic(
    longitude,
    latitude,
    height * 0.5
  );
  const position =
    viewer.scene.globe.ellipsoid.cartographicToCartesian(positionCartographic);

  const camera = viewer.camera;
  const heading = camera.heading;
  const pitch = camera.pitch;
  const direction = viewer.camera.direction;

  const ScaleDirection = Cesium.Cartesian3.multiplyByScalar(
    Cesium.Cartesian3.negate(direction, new Cesium.Cartesian3()),
    height * 2,
    new Cesium.Cartesian3()
  );
  const cameraPos = Cesium.Cartesian3.add(
    position,
    ScaleDirection,
    new Cesium.Cartesian3()
  );

  camera.flyTo({
    destination: cameraPos,
    orientation: {
      heading: heading,
      pitch: pitch,
    },
    easingFunction: Cesium.EasingFunction.QUADRATIC_OUT,
  });
}