Softdisk was the company where John Carmack, John Romero, and Adrian Carmack met and developed games originally before founding id Software. Those original Softdisk game titles are now being open-sourced under the GPL. The original Softdisk games created by the id Software founders are now owned by Flat Rock Software. Flat Rock Software has decided to go ahead and open-source these old classics. Among the games with their sources out there are TheCatacomb, Catacomb3D, Catacomb, and Hovertank3D ... The engine is open-sourced under the GPLv2 but the game data still requires having a licensed copy of the content. The original Catacomb was written in Borland Turbo Pascal 5.5 while at least Hovertank3D and the newer Catacombs are written in C++.
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