写一段cesium中旋转模型的代码

以下是一段使用 Cesium 中旋转模型的代码示例：

var viewer = new Cesium.Viewer('cesiumContainer');

var modelMatrix = Cesium.Transforms.eastNorthUpToFixedFrame(
    Cesium.Cartesian3.fromDegrees(-75.62898254394531, 40.02804946899414, .)
);

var model = viewer.scene.primitives.add(Cesium.Model.fromGltf({
    url: 'path/to/model.gltf',
    modelMatrix: modelMatrix,
    scale: 200.
}));

var initialRotation = Cesium.Quaternion.fromAxisAngle(Cesium.Cartesian3.UNIT_Z, Cesium.Math.toRadians(45.));
var modelOrientation = Cesium.Transforms.headingPitchRollQuaternion(modelMatrix, new Cesium.HeadingPitchRoll());
var finalRotation = Cesium.Quaternion.multiply(modelOrientation, initialRotation, new Cesium.Quaternion());

var startTime = Cesium.JulianDate.now();
viewer.clock.onTick.addEventListener(function(clock) {
    var elapsedTime = Cesium.JulianDate.secondsDifference(clock.currentTime, startTime);
    var rotationAngle = Cesium.Math.toRadians(elapsedTime * 10.);
    var rotation = Cesium.Quaternion.fromAxisAngle(Cesium.Cartesian3.UNIT_Z, rotationAngle);
    var newOrientation = Cesium.Quaternion.multiply(finalRotation, rotation, new Cesium.Quaternion());
    model.orientation = newOrientation;
});

注意：以上代码仅供参考，具体实现可能需要根据具体场景进行调整。