该程序可以使用opengl从.stl文件读取并显示对象。 用户可以旋转，缩放并选取片段。 点击左键会选择片段点击左键并拖动鼠标可以旋转点击右键会放大和缩小物体(The program can read and show the object from the .stl file using opengl. The user can rotate, zoom and pick the fragment. click left button will pick the fragment click left button and drag the mouse can rotate click right button will enlarge and shrink the object)