SKSE Plugin Development

[SKSE64 2.2.6 Revision]

The Skyrim Script Extender (SKSE) is a tool that enhances the capabilities of Papyrus scripts and adds additional functionality to the game, as well as allowing modders to create plugins to further extend Skyrim's scripting capacities. SKSE plugins take form as .DLL files that usually implement new functions into Papyrus, Creation Kit's scripting language. As you may guess, making an SKSE plugin is more difficult than using Papyrus, but you are free of many limitations that Papyrus has, and using C++ might improve performance dramatically where comparable.

Requirements

• Skyrim Special Edition
• SKSE for Skyrim SE (Also referred to as SKSE64), which you should already have installed.
• Visual Studio 2022 Build Tools. You don't need to install the entire IDE if you won't use it.
• An IDE like Visual Studio, VS Code or CLion. xieve recommends using CLion if you have not used Visual Studio before, as it will manage installation of vcpkg automatically, among other things.

Ensure that your Windows and SKSE installations are up-to-date. If Skyrim Special Edition has not received an update in the previous week or so, you will want that up-to-date too. See the official SKSE page to see which version is currently supported. Please keep in mind that this guide does not guarantee backward/forward compatibility, and things keep breaking in unforeseen ways.

Setup

The easiest and recommended approach is to use a template plugin. This one is currently (as of 2024-11-16) recommended for CommonLibSSE-NG. See here for a comparison of the different CommonLibSSE versions.

Follow the documentation that the template plugin of your choice provides, it will be more up-to-date and applicable than any external resource.

Should you want to, you can set environment variables inside CMakeLists.txt like so:

set(ENV{VARIABLE_NAME} "Variable value")

For example:

set(ENV{SKYRIM_MODS_FOLDER} "C:\\Games\\MO2\\mods")

Making a plugin

As of 2024-11-16, there is no definitive resource on SKSE plugin modding.

These are related sources that have inspired this guide. Please note that the instructions may differ from one source to another and that some might simply be completely wrong/outdated.

• Ryan-rsm-McKenzie's Tutorial on GitHub. Most notably, includes documentation for debugging setup and CommonLibSSE's Papyrus API.
• The original SKSE64 source code on GitHub, which, in contrast to CommonLibSSE, has comments! You should definitely check this out as it is probably the best documentation you will find. I recommend cloning (downloading) this repository and checking it out in your IDE so you can search it more easily.
• Skyrim.dev - SKSE
• Unofficial auto-generated documentation for CommonLibSSE, CommonLibVR and CommonLibSSE-NG
• MrowrPurr's Discord. You can ask SKSE- or Papyrus-related questions here.
• Zartar's "noob tutorial" on Bethesda's old forum. The whole discussion may contain other helpful information too.
• This Reddit discussion on weird errors while trying to set up a plugin template

Generally, SKSE plugin development heavily depends on a good IDE that allows you to browse the SKSE and CommonLibSSE sources, and on reading other people's source code on GitHub.

If you chose to use CLion, navigate to <Project Directory>\build\debug-msvc\vcpkg_install\vcpkg\pkgs\commonlibsse-ng_x64-windows-skse, right-click it and select Mark directory as→ Library Files. Now, when you hit shift twice to invoke Search Everywhere, all the CommonLibSSE symbols will show up in your search!

Implementing new methods

SKSE Plugin cannot override or extend already existing Form classes. In other words, consider an "ObjectReference" object and a "newMethod(<parameters>)" function you want to implement as an interaction of ObjectReference. You won't be able to implement ObjectReference.newMethod(<parameters>). Instead, you can create a new "MyScript" object and implement MyScript.newMethod(ObjectReference, <parameters>).