I've read more into it and my view is that the linking argument is nonsense in the context of RTC.
Three small libraries don't make the RTC game code a "derivative work" of those libraries. In this context, the applicable point of view is the one labelled on the
Wikipedia article as "Point of view: linking is irrelevant".
One can't subscribe to the third "Point of view: any linking violates GPL" in the context of RTC. This POV states "an executable is indeed a derivative work if the executable and GPL code "make function calls to each other and share data structures". Clearly, RTC calls functions from these libraries, but it's one way only and no data structures are shared.
In any case, even if an argument for violation WAS held up in a court, it doesn't matter because the libraries George has used ARE NOT COVERED BY THE GPL. So this whole GPL discussion, in the context of RTC, is rather pointless!
Sophia was a bit wrong about claiming that the libraries require attribution, here's what each lib's licence says:
ZLIB (Compression):
"If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required."
LIBPNG (Support for PNG graphics files):
"The Contributing Authors and Group 42, Inc. specifically permit, without fee, and encourage the use of this source code as a component to supporting the PNG file format in commercial products. If you use this source code in a product, acknowledgment is not required but would be appreciated."
FMODEX (Sound functions/format support library):
"FMOD Non-Commercial License: If your product is not intended for commercial gain and does not include the FMOD library for resale, license or other commercial distribution, then use of FMOD is free. Yes that's right, free from license fees!. When using FMOD, a credit line is required in either documentation, or 'on screen' format (if possible). It should contain at least the words 'FMOD Sound System' and 'Firelight Technologies'."
So the only credit/licence requirement that GG is in breach of is the FMODEX one. I suspect that George tried hard to find truly free libraries exactly to avoid the whole licensing issue.
I'd like to see it open source, as I've stated, for my own ends, and that of the greater community
We've had this discussion here before and the fallout messed up our community for a while (search the archives if you like). While I wouldn't want a repeat performance, I think this is an interesting discussion, but please be mindful of sensitivities on both sides.
I agree that it's frustrating, but from a different perspective as a budding dungeon builder: RTC still contains a lot of bugs that make it impossible to use some of the nicer effects. Just check out the RTC bugs forum to see. I don't care about the open source thing, but with George no longer working on the project, it means no bug fixing. I'd at least like him to "lend" the code to a responsible person to take over and bug fix so that the project doesn't stagnate. But what I would like counts for nothing since it's George's decision at the end of the day.
It's also a shame for those of us who put a lot of our own time into helping the project become what it has. Between '00 and '03 I spent most of my spare time playtesting it, finding tons of problems, reporting them and helping improve it. I still do now. I made a key early suggestion on how to improve the engine over the original and Sophia contributed significant ideas (and maybe code?) to the extended engine that came with the later versions. Many of the rest of us have too
I don't think it's unreasonable to say that RTC would not be where it is without our help. I understand that this gives me no rights over how the game is developed and released, but I do feel it's a shame that (a) our significant contributions have not really been recognised and (b) RTC bugs prevent some cool features from being used.
I'm keen to see RTC continue to grow, but I have to accept that it probably won't.