Regarding ZDoom's Heretic/Hexen Support

[Xtyfe]

I recall hearing at one point that ZDoom originally reverse engineered code from Heretic and Hexen to make support for them GPL capable before the source code to those games were officially released under the GPL. Is this true? and if so was that code ever replaced with the official versions of them when Heretic and Hexen were released under the GPL?

[NeuralStunner]

AFAIK ZDoom's only reverse engineered code is Strife support.

[esselfortium]

ZDoom itself isn't GPL-compatible, making use of code from various sources in a tangled mess of licenses that may or may not have any legal basis, so the GPL rerelease of the Raven code was a non-issue here.

[Graf Zahl]

I recall hearing at one point that ZDoom originally reverse engineered code from Heretic and Hexen to make support for them GPL capable before the source code to those games were officially released under the GPL. Is this true? and if so was that code ever replaced with the official versions of them when Heretic and Hexen were released under the GPL?

I don't think there was any reverse engineering. Some of the initial support for Hexen had some new code based on guesswork and observation but some of it was replaced later by the original (the floor waggling the most significant, I believe.) Other code, however, kept the initial ZDoom imlementation and never went for Hexen's (ACS and earthquake handling, for example)

All the monster related Hexen and Heretic code was only added after the first non-GPL source release.

[Gez]

I recall hearing at one point that ZDoom originally reverse engineered code from Heretic and Hexen to make support for them GPL capable

No. The reverse engineering done on the Raven games wasn't for any GPL-related reasons; it was because the source code was unavailable at the time.

ZDoom itself [wiki=license]cannot use GPL code without special authorization from the right holders[/wiki].

I don't think there was any reverse engineering. Some of the initial support for Hexen had some new code based on guesswork and observation

And that isn't reverse engineering? RE is not limited to disassembly.

[Graf Zahl]

No. Reverse engineering means to take the subject apart to see how it works, not to observe how it works. That may be nitpicky but it's an important distinction, especially legally.

[Xtyfe]

I don't think there was any reverse engineering. Some of the initial support for Hexen had some new code based on guesswork and observation but some of it was replaced later by the original (the floor waggling the most significant, I believe.) Other code, however, kept the initial ZDoom imlementation and never went for Hexen's (ACS and earthquake handling, for example)

All the monster related Hexen and Heretic code was only added after the first non-GPL source release.

I see then, that settles my curiosity