从PChome得到的代码，很适合初学多线程的人。使用双线程模拟彩色降雨，并且可以使用鼠标控制风向和雨量，暂时没有声音文件-From the PChome code, it is suitable for beginners multithreaded. Double thread the analog color rainfall, and can use the mouse to control the wind direction and rainfall No sound files