unity3d漫游脚本，鼠标控制方向，滚轮控制速度;W前进，A左平移，S后退，D右平移，R上升，F下降，使用时把脚本拖到摄像机上，然后给摄像机添加character controller，运行程序就可以用了(Unity3d roaming scr ipt, mouse control direction, the roller speed control; W forward, A left S D right back, translation, translation, R increase