实现点云文件的读取与显示，要求点云文件是DAT文件，文件头是点数乘以3，其后是每个点的具体坐标。可以用鼠标进行交互-The realization of point cloud file to read and display requested document is a point cloud DAT files, the first is multiplied by 3 points, followed by the specific coordinates of each point.