I've been stumbling around in the figurative dark for a while now, trying to understand the process of hooking a direct X screen. Specifically, I want to hook BYOND's screen so that I can draw on it from C# and XNA.

But delving too deep into scarcely charted shafts of knowledge gets pretty convoluted pretty fast, and unfortunately I've got a slew of priorities to attend before I can really sink my teeth into the mysteries of the various libraries and demonstrations I've downloaded.

In my frustration I wanted to find a sanity check that would prove that hooking BYOND's screen could actually be done. I then remembered FRAPS, and decided to give it a shot. And lo' and behold -- it works!

So it's possible. (As suggested by a certain BYOND member in the developer forums). But what's the simplest way to go about what I'm trying to do?

I understand I need a dll in unmanaged code (C++, more than likely), and that that dll needs to supply the functions for the actual hooking. However, a dll can't be launched by byond. So it would have to launch a program to launch the dll.

Additionally, I'm assuming the program would have to launch the dll so that it would inject itself into the BYOND's process space. This means further complication.

So the theoretical model looks like this:

BYOND app/game -> C# exec -> C++ dll

Now another problem becomes, how do I push the C# XNA direct X screen through the C++ dll and back to the BYOND app/game?

BYOND app/game <- C# exec <- C++ dll

Any ideas, suggestions, examples, or links welcome!