实现一个灵活的摄像机类，它可以用作飞行模拟摄像机和第一人称视角摄像机,用户接口对于要响应用户输入来实现摄像机移动-To achieve a flexible camera class, which can be used as flight simulation camera and first-person perspective camera, the user interface for the need to respond to user input to achieve the ca