[HashGrove]

AlexSleyore, on 23 July 2012 - 12:42 AM, said:

Even if a game isnt open source, its still possible. You would however need an understand of the Assembly language. to add another player, you would first need to find your players class in your game(his X,Y,Z, Mess and model information, his models stance, etc) then you would make an inject-able DLL that actively reads and send this data to a PHP file on a server - this file would then send your information to your friends computer if hes connected - and his data back to you. His computer would take your players class information - and add you as a non-interactive item to his game.

-technically since you only want it to be 2 players - you can skip the server, and use each others IP addresses to send the information directly to one another - this can be useful for checking multiplayer information - without paying for a server that allows you to use sockets.

your probably much better off working in an open source sdk, or learning packet sending and receiving on your own - besides there is absolutely no money in doing all that work to someone elses game.

Right, most of this I understand but still I'm stuck at the part of finding a players class. Naturally I understand the concept but the how to is a bit of a problem (when is it not?) . So if you could point me to some topics or something similar.

I understand how to make a server and client application but how do I pinpoint it to send specific information?
Even more, how do I make it use that info for the games purposes?

I know these are not really precise questions but there is a lot of confusion when I try googling or reading about this stuff.

[ButchDean]

RudiVisser, on 23 July 2012 - 02:23 PM, said:

ButchDean, on 23 July 2012 - 01:41 PM, said:

^ No, not at all. You cannot derive source from disassembled code. Nonsense.

You can derive basic functionality, but not add a complete multiplayer element to a closed source game.

Well that entirely depends on how the game was built. Overriding drawing of a single player to handle two player objects (assuming that the player is an object instance) is not so difficult.

Show me one single game you can disassemble to its source. Just one.

[AlexSleyore]

You cant disassemble any program back to its original source code, Obvious reasons would be the arbitrary names given to variables are not preserved after compiling. You can however use Disassemblers to get you close to the original source code without any of the variables having useful names. The best example of this I feel would be hex-rays. However what he was talking about can be done with OllyDbg by finding the base address of the players structure, then finding the base addresses pointer - from there you set an on read breakpoint on the address pointer and every function that uses your player pointer, you call twice - once with the original pointer, and once with the pointer to the new 2nd players player class pointer.

[ButchDean]

But you are assuming so many things. What about:

1. Encryption?
2. Proprietary formats?
3. Unfamiliarity with the code base?
4. Compiler optimizations?
5. Linked code from other libraries?
6. Platform quirks?

I am very aware of what you are saying since reverse engineering was a large part of my job in research and development for games at a studio. Disassembly only allows you to derive and idea of the overall logic of the code base on which you focus on a particular point of interest for study - it will not allow you to rewrite the game with different variable names as though the source where originally written by yourself.

[RudiVisser]

ButchDean, on 24 July 2012 - 09:34 PM, said:

Show me one single game you can disassemble to its source. Just one.

I never said you could!

But it's certainly possible to modify how something works and add to what it does, even without the original source; which is essentially what you yourself said, just with a tag of basic functionality, rather than something more advanced which could certainly be possible.

However, almost certain that 80% of XNA games will decompile straight back to source, based on the (likely) lack of obfuscation.

[AlexSleyore]

I'm not assuming anything - I'm just not writing a 10 paragraph explanation on how each any small flaw in the reversed code can be easily overcome by someone who knows what there doing.

[macosxnerd101]

I think it's a moot point anyways, because we're not helping people do such a thing here. If you've written your own game and want to extend it, great. If a game provides an API or a set of tools to create mods, fine. Otherwise, we're really not going to help someone tamper with someone else's intellectual property and software.