How can I learn a multitouch screen's communication protocol and write a C# application for it?

I have got a monitor with multitouch overlay on top of it. It works fine with Windows 7 but I want to write a multitouch application in C# for Windows XP which doesn't support touch feature out of the box. There is no documentation开发者_运维百科 whatsoever and I emailed the manufacturer but never got a reply.

However the device works with Google Earth, which doesn't natively support multitouch, on Windows XP. So I think it generates many types of messages together i.e. WM_TOUCH for Windows 7, one for Google Earth COM API, and probably its own messages either in UDP or Windows message form. How can I trap all communications and learn the protocol?

OllyDbg is a very low-level debugger that allows you to see a lot of the messages going back and forth on the machine. I've seen it used to reverse-engineer a USB device driver's messages to figure out how to interact with an item.

I suspect that would be an excellent place to start. It should allow you to determine how the messages are being passed and, perhaps, start teasing apart their structure.

There are solutions like Tuio around that do not rely on Windows 7. Maybe a tuio (or alternative) implementation would make you life easier.

I've recently been developing on the Windows 7 platform for multitouch. I'm using UniTuio -- see http://xtuio.com You can look at my question I had to get it working. I'm also using a bridge for Windows 7 called Touch2TUIO, it seems to work quite well. If you need to make the mouse inactive see my question here: using windows 7 with unituio