点击屏幕，模糊拾取3D世界中的线段。即求射线和线段间的距离。-Tap the screen, fuzzy pickup segments in the 3D world. That is seeking rays and the distance between the segments.

这是3D闹钟在可触碰的显示器上的多点触碰代码。实现旋转，拖动，轻敲等功能。-This is the alarm clock in 3D on the display can be touched multi-touch code. Achieve rotation, drag, tap and other functions.

osg图形引擎中点选功能，点选到图片或物体后做相应的处理-After osg tap graphics engine features, click the image or object to be handled accordingly