Sources Modifications
MultDoom v0.4
Based on NTDoom. MultDoom allows 2 players to play Doom on the same computer. Here is the original description by Kokak:

After the publication of the Doom sources, I could finally carry out an old dream: Two players playing Doom on a same computer!
This first version was based on the idea rather simple to replace the low-level network functions (sendto and receivefrom) by accesses to a memory shared by two Doom processes launched on the same machine. In fact this version 0.4 functions very well on a bi-processor PC under Windows NT. On the other hand, on a mono-processor (P200 nevertheless!), the process in background is much slower compared to that which has the focus. While increasing the priority of the background process, one manages to have something of playable, but animation is not worthy of P200..
I plan to carry the thing under Linux, to see how this last will react...
I based myself on the sources of NTDoom de Petteri Kangaslampi.

MultDoom is not available for download, download WDMP (below) instead.

WDMP (Windows Doom Multi-Player) v0.9
An enhanced version of MultDoom, this allows up to 4 players to play a multiplayer game of Doom on one computer. It is the only thing I know of that can do 4 player splitscreen (Doom Legacy can do 2 player). Here is the original description by Kokak:

The limited results obtained with MultDoom encouraged me to seek another method.
Only one Doom process will manage all the players (a window by player). As you can imagine it, the modifications to be made to the engine of Doom are, in this case, a little more consequent...
This version is also based on the sources of NTDoom.
I chose NTDoom because it is the only one which does not use DirectX. So, WDMP runs on a 486DX2/66 with 8Mo under Win32s!

Download WDMP v0.9 binaries.
Download WDMP v0.9 source code.
Download WDMP Setup Utility by Jaromir Smid.

Data Modifications
Wolf3d to Doom maps converter
Converts Wolf3d maps to Doom wads.

I wrote this converter approximately four years ago.
It is integrated into DEU. A new command was added to this last. One indicates to it which map one wants to transform, and it generates Wad file. It should then be edited in DEU, in order to generate the BSP.

Download Wall Textures WAD.
Download Wolf3D resources.
Download converter sources.

Dark Forces to Doom Data Exporter
Exports Dark Forces data to Doom format.

This small program was written little after the converter of Wolf3D's maps. However, for lack of time, only the resources (sprites, sounds, textures) of the shareware version of Dark Forces have been "doomised " (no maps converter was made).
Those converted datas run well in a Star Wars doom level.

Not available for download.

Doom textures to Duke3D
Exports Doom texures to Duke3d format. For use with the Doom wad to Duke3D map converter that comes with Duke3D.

With Duke3D is delivered a converter of maps Doom towards Duke. It is very well. But when one sees textures on the grounds and the walls, it is less better!
The converter that I wrote, exports all textures of a Doom Wad towards a tiles0??.art of Duke3D.

Download now.