- See classic Doom for the collective range of id Tech 1 Doom games. For the iOS port, see Doom Classic (Iphone and Ipad)
Doom Classic is the name given to Id Software's modern cross-platform port of the original Doom engine. It is based on the Xbox 360 port created by Nerve Software and was ported back to PC when it was included with Doom 3: BFG Edition.
Outside of the BFG Edition, it is also present in the Doom Classic Complete package for PlayStation 3 (but not in the PC version of that package, which still uses the original DOSBox executables).
Technical details
The source code contains extensive modifications to integrate the Doom engine into the id Tech 4 external framework, which can regularly call the engine code to provide rendering context, audio streaming, and input events. You can exit the game to return to this frame, and a special menu is provided to change the current game from within the game itself.
As part of supporting the ability to reset the game engine without exiting the framework, as well as supporting multiple simultaneous instances of the engine in order to support split-screen multiplayer (a capability for some reason disabled in the BFG Edition for PC ), most of the program's global variables have been moved to a C++ class. It also raises some static limits, making it capable of playing the Doom II: No Rest for the Living expansion.
On some platforms, the id Tech 5 network code is used to achieve network playback capability. However, it is not obvious that this code is included in the source version, or that it will be able to compile and work even if it is included.
Most of the bugs in the original DOS codebase remain unresolved, and anyone with the ability to invoke undefined or illegal behavior will crash the surrounding id Tech 4 shell with an illegal operation dialog typical for the platform.