It is recommended that you read tutorials to get a foundational understanding of UnrealScript and how the engine works (particularly the 3D Buzz Video Tutorials), but it is even more important to browse existing code and see ‘how they do it.’ Once you have an objective for your first mutator, you can search around existing code to try to figure out how to do it.

Install a Text Editor

As Windows does not come with a decent text editor, you will need to install one if you have not already. We recommend using Notepad++, which was rated the #1 Text Editor by Lifehacker.

Decompiling RO Source Code

The first thing to do is Install Red Orchestra SDK. Apart from giving you the editing software, doing this will automatically decompile all of the Red Orchestra code packages from the system directory, allowing you to view the source code and see how things are done. After doing this, you will notice several new folders in your Red Orchestra Game Directory that correspond to .u files in your Red Orchestra System Directory (e.g. \Red Orchestra\RO_Engine\ is the decompiled classes from the \Red Orchestra\System\RO_Engine.u package). Inside these new folders (in the Classes subfolder) you will find .uc files, which can be opened in a text editor and contain the actual code that makes the game work.

Decompiling DH Source Code

The process for viewing the Darkest Hour source code is not as easy - you have to manually decompile each package. If you browse to your Darkest Hour System Directory, you will find the following .u files, which are compiled code packages.

  • DH_ATWeapons
  • DH_BritishPlayers
  • DH_Effects
  • DH_Engine
  • DH_Equipment
  • DH_Game
  • DH_GerPlayers
  • DH_Guns
  • DH_Interface
  • DH_USPlayers
  • DH_Vehicles
  • DH_Weapons

These packages can be decompiled using the instructions found here. While it would be possible to create a batch file that automates this decompiling process, learning how to decompile is a vital part of getting started.

Decompiling Other Mutators

If you come across other mutators that do something and you’d like to know how, you can decompile it and find out. Just place the .u file in your Darkest Hour System Directory and decompile it. If it is a Red Orchestra mutator, put it in your Red Orchestra System Directory and decompile it by changing the path (no need for ..\DarkestHour\) and removing the -mod=darkesthour suffix.

You should be able to decompile Unreal Tournament 2004 mutators as well, but sometimes they have dependencies on Unreal maps/textures, etc. that we do not have with Red Orchestra. If you’re feeling determined, you can download the Unreal Tournament 2004 Demo to get the packages and decompile it.