Passing c++ methods/pointers to C# Managed code

[Baaleos]

Hi All,
I am interested to know if there is a way to have say

RunScript and Set/GetLocal* hooked in c++, and then passed to managed c# code.

There is a nwnx dotnet plugin out there, but what I am looking for is a stable way of interacting with the nwn module, from the outside world.

Eg:

In .Net you could spawn a windows form on a separate thread.
And in theory, you could have a button that when clicked, fires the RunScript method in nwn.


In order to do this with nwnx_dotnet, I'd imagine I need to pass a pointer of the RunScript method or something, to the C# environment, from the c++ domain, eg: c++ is used by nwnx to locate the pointer, and then invoke it like an ordinary method call from the c# code.

Does this sound feasible?
What im trying to do, is integrate a .net web application with my PWServer.

Eg: Click on a character, on the server status screen, and kick them, and have them instantly kicked - without needing to use polling scripts / heartbeats.

[Baaleos]

I've seen a website that suggested invoking the RunScript method from a nwnx_* dll with pInvoke.

Eg:

[DllImport("nwnx_cool.dll", SetLastError=true)]
static extern int RunScript(string sString);


Is there special requirements required to make methods within c++ dll's invokable in this methodology?


I hope that if I create a wrapper method in c++ (with the bare minimum amount of c++ required)
and then do the DLLImports, I should be able to call RunScript and other methods with relative ease?

Does this sound possible?

[Baaleos]

Realise Im kinda answering my own posts here....

I've read something about.

[Terra_777]

You can't export code to another application since the application that you export too does not run in nwservers memoryspace and as thus would crash the moment you try to call RunScript as it doesnt exist on that address. Instead what you want is to inject code into nwserver (which is what nwnx does for you) in order to reach the methods within nwservers memoryspace.

If two separate application are to communicate you need a medium to communicate though, an example on this is SQL/Database where you got the game exchanging information with the outside using the database which you can then manipulate using PHP for example.

I've never worked with C# but what you want to do is make a C# module (if thats even possible) and have a nwnx plugin import it, then from the nwnx plugin you call a method from your C# module every tick/frame/mainloop whatever to check your events. The C# module would then rely data back to nwnx using the nwnx_plugin as a medium of communications between them.

Another such medium can be network communication where you can establish a connection on the loopback this is what the game does when you connect to the database on a lower level. It'd however require a hook in the mainloop to check for incoming data every tick/frame so basically you'd have to establish your own protocol. IE:

[Baaleos]

Hey Terra,
I am having a go with your bridge plugin again,
I was just wondering if you can confirm its usage.

I am able to send it messages, and for the most part it seems to be handling them correctly.
However, occasionally when used, it causes the server to hang : no error message or anything, just like it gets stuck in an infinite loop in the code somewhere.

The code I am using to test the bridge is this:

its in C#

[Terra_777]

The server I wrote isnt any good, its a forking server where it forks of connections to new threads instead of being asynchronous. Its not a very good approach at all so its bound to be problems with it. Could create (or help create) a simple plugin that opens a socket and relies all info to nwscript events when I got time.
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[Baaleos]

Ah, ok
Well what you've produced with the bridge functionality of nwnx_cool is still good enough for proof of concept ideas: Just means I need to be careful how I use it.

Wish I could help you, but I dont know enough c++ to do socket/networking.
If it could be done in c#, it would be a breeze,
alas - the nwnx interface is c++.

[Terra_777]

http://www.codeproject.com/Articles/42319/Using-NET-Classes-Modules-from-Native-C

Came across quite an interesting read for you Baaleos.
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[Baaleos]

Hi Terra,
Yeah its interesting: I've already got nwnx_dotnet with some ammendments that allow me to invoke external .net dll's programatically.

http://nwnx.org/phpBB2/viewtopic.php?t=1002&start=30

Source code available here.

The only problem with it is that it doesn't allow 2 way communication to nwnserver.


eg: I can create an instance of a c# class from the nwnx plugin, but that class once instantiated, is not able to reach back into the nwnserver domain, and execute c++ methods.

I am sure its possible to do, im just not sure how to do it really.
I've done something similar when working with vb script and c#

in VB Script getRef allows you to get the memory pointer to an address in memory, if that memory points to a method, you can then use Reflection to execute that object as a method, with the desired arguments.

[Terra_777]

Marshal.GetDelegateForFunctionPointer Method (IntPtr, Type)

Only virtual machine language I've integrated using C++ is lua but C# is also a virtual machine language so somewhere there should be a way to register methods or classes in C#. I think the above function I linked is what you're looking for.
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[Baaleos]

[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate int MultiplyByTen(int numberToMultiply);

[Terra_777]

I assume you have to make a specialized function for it.

Quick google later: http://stackoverflow.com/questions/2470487/call-c-function-pointer-from-c-sharp

I don't actually know how it works in C#, but yeah, any plugin loaded by nwnx runs in nwserver's address space.
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[Baaleos]

Thanks for the help Terra,
I was wondering if you might know if the Marshal class also allows me to return struct/objects from memory, as well as the methods based on their location/pointer?

[Terra_777]

No, you still have to write a function in C++

ie:

[Baaleos]