PrBoom

PrBoom, originally short for "Proff Boom", is a source port for Windows, Linux/POSIX, OpenVMS and Mac OS X based initially on Boom, but later merged with LxDoom and LsdlDoom. As a result of this merger, PrBoom is compatible with both Boom and MBF. It includes OpenGL features for the renderer (as GLBoom) as well as some enhancements over the engines it is based on, such as being able to handle levels with twice as many segs, vertices and sidedefs than usual. In addition to the code from its predecessors, it incorporates bits of code from the Eternity Engine, and PrBoom+.

PrBoom is currently maintained by Florian Schulze (Proff), with contributions from Andrey Budko. Colin Phipps (cph), who accompanied Proff for the first few years after the merge with LxDoom, has retired from the PrBoom development team.

Unlike other source ports that concentrate on offering many new game features or changes, such as ZDoom, EDGE and the Eternity Engine, PrBoom aims to act as a stable port of the more established or traditional engines.

PrBoom uses the SDL library to abstract away operating system or platform specifics. As a result it supports a very large variety of platforms In addition to the PC, it has been compiled for the GP2X and various Mac models, among others. The source port, packaged with Freedoom, is included in the Fedora RPM software repository.

Compatibility modes and settings
PrBoom supports various of compatibility settings to adjust its behavior, much like those initially implemented for MBF. In addition to individual settings for each difference in behavior, it allows the user to set compatibility levels to behave like earlier versions and modifications of the Doom engine. With the compatibility levels PrBoom may provide almost flawless compatibility with regular demos, as well as those recorded with Boom engines.

To change compatibility levels, the cheat code TNTCOMP can be used ingame. The game can also be launched with the -complevel parameter, or with default_compatibility_level in the config file, followed by one of the following numbers:

There are other compatibility levels available for several versions of Boom and PrBoom, refer to the README.compat file in the PrBoom source code for complete details. In practice, complevels 2 and 9 are the ones used in the overwhelming majority of cases.

Demo recording
PrBoom's compatibility with demos from the plain Doom engine, Boom and MBF also allows it to behave like these while playing, whether recording new demos or not. PrBoom in Doom compatibility mode treats straferunning differently than usual, which makes it possible to identify demos recorded with it. This is due to the Compet-n rules which require demos to be recorded with the DOS executables included with the games. In addition, PrBoom includes features which make it possible to "cheat" by using saved games to record demos in several stages. The offshoot engine PrBoom+, on the other hand, has all the compatibility options of PrBoom yet treats straferunning in the same way as the unmodified games.

When using a compatibility mode during demo recording, PrBoom marks the resulting demo with the corresponding version header information. Since PrBoom can handle larger or more detailed levels than its predecessors, this may produce demos that are not compatible with the engine versions it is emulating.