There is osgGA::GUIEventAdapter in OpenSceneGraph that could detect mouse events. However, I want the program to detect two mice on the same computer and the program can only treat two mice as one. I know there is a Windows MultiPoint Mouse SDK, but I think it is used in WPF with C#, not sure if it could be used in C++
Also, there is a GlovePie, but it is not open source and not sure how to use that in vs2010.
VRPN may be a good choice, but do not know exactly how to implement two mice. Get the dll files of two mice and extract functions by vrpn?