I'm interested in beginning a project like Open Transport Tycoon Deluxe (openttd.org) or the TA Spring project (http://springrts.com/) primarily for my own learning/enjoyment.

Specifically, I would like to take an old Windows game and port it to Linux. I'm not interested so much in playing the game as I am interested in learning about the whole process and what it will involve.

Firstly, it would be appropriate to ask if this is a legal thing to do. Presumably it depends upon the current state of the game's IP, who owns it and whether they care?

Secondly, where should I be looking to learn about all aspects of a project of this scope? What particular topics should I be considering at the outset?

Initial points I have considered:

* Graphics libraries in Linux (OpenGL, SDL)

* Reverse engineering of executables

* Unpacking binary files (maps, textures etc) in whatever proprietary format is in use by the game

* Network programming and how to update older protocols (pre TCP etc) for multiplayer aspects

* Looking at the source code for other open games (FreeCol, FreeCiv, OpenTTD etc.)

Any comments would be extremely useful.

Thanks in advance.

Mike.