Caves of Qud presents a broadly extensible engine. The game's core definition files reside in
You can create mods for the game by creating a Mods folder in the same parent directory where your Saves are located, and then creating a sub-folder inside of the Mods folder for your new mod. New content can be created and existing content can be modified or replaced via data files and textures placed in this directory.
For the exact mod folder locations for your operating system, see file locations.
A (partial) checklist for getting ready to mod
- If your file manager (such as Windows Explorer) hides file extensions, tell it to show them instead. Being able to verify you're using the correct file extensions is vital when programming.
- Install a programming text editor, such as Visual Studio Code (all major platforms), Sublime Text (all major platforms), or Notepad++ (Windows only).
- Visual Studio Code in particular, paired with Microsoft's C# extension for it, is very useful if you plan to write any script mods.
- Word processors (such as LibreOffice Writer and Microsoft Word) are unsuitable for modding the game, because they deal primarily with formatted text, as opposed to plain text.
- If you cannot install a programming text editor for whatever reason, Notepad is essentially useable, even though it's missing certain features usually considered desireable for programming, such as syntax highlighting and line numbering.
- If you plan to mod in your own tiles, familiarize yourself with a pixel editor, such as Piskel (all major platforms and web).
- GIMP is essentially useable, but it isn't designed specifically for pixel art and may take more work to make game tiles with it than with a dedicated pixel editor.
I'm stuck and don't know what to do. Feel free to ask for help or guidance in #modding on the official Caves of Qud discord server! There are several modders there who use the channel to talk through and ask for feedback on their mods.
How do I troubleshoot my mod? A good place to start is by reading the following files that are updated every time the game runs:
build_log.txt: Includes compiler errors if your mod code has errors that will not compile. These errors can prevent your mod from being loaded at all.
Player.log: Includes XML errors and other miscellaneous errors that can prevent your mod from working as intended, even if it does load. Search the file for
MODERRORstatements, and review carefully for other output lines that mention your mod.
Where can I find
Player.log? See file locations.
My mod has been marked incompatible on Steam Workshop. What do I do? Update your mod to work with the latest stable or beta release of the game, then request that your mod be unmarked incompatible via either the official Caves of Qud Discord server's #modding channel, or the support email address, firstname.lastname@example.org.
I keep getting an error when trying to save my game. Most likely, you have a list in your mod. Qud's default method of saving doesn't handle lists, so you need to handle it yourself. To see how, check out this article on how to override Qud's default saving/loading.