UE4SS fix for ITR2

The issue: Logic Mods load on first map but disappear after loading another map and never come back (until exit/restart).

This happened with the Clean Repack on Nexus as well as the latest experimental version on GitHub.

Here is a replacement main.lua file that fixes this UE4SS problem for the ITR2 1.x release.

Put it in the folder ...\ue4ss\Mods\BPModLoaderMod\Scripts

This main.lua file should be incorporated into any ITR2-specific version of UE4SS.

I assume it will be added to the existing repack on Nexus eventually: https://www.nexusmods.com/intotheradius2/mods/128

I am posting this for those that want to use the latest experimental version of UE4SS, available on GitHub (which also fixes an Ftext error that popped up in the stable version of UE4SS 3. 0. 1 with the ITR2 1.x release):

https://github.com/UE4SS-RE/RE-UE4SS/releases

How I created this - I explained the problem to Claude, which made a number of suggestions, most of which I had already tried. The number 5 suggestion was to manually edit the main.lua file in that folder.

I uploaded the existing main.lua file and asked Claude to make the changes for me. It sent me a new file, and that didn't work. I informed Claude and it tried again. This one worked.

Claude's explanation:

"Let me look more carefully at the actual UE4SS experimental source and any ITR2-specific issues. This is the critical clue. ITR2 uses seamless travel between maps — which means UEngine::LoadMap is never called for the transition, so RegisterLoadMapPostHook will never fire. That's why both my fix and the original didn't help. The hook is simply the wrong one for this game.

The right approach is to use RegisterInitGameStatePostHook, which fires on seamless travel too, but the problem is that the GameMode context it passes doesn't directly give you the new world easily. The most reliable workaround for seamless travel is hooking AGameMode::StartPlay or using RegisterBeginPlayPostHook to detect when a new world is ready. Let me write you a version that uses multiple hook strategies as fallbacks. The key insight I missed before: ITR2 uses Unreal's seamless travel system (ServerTravel/SeamlessTravel) to move between maps. Seamless travel deliberately bypasses UEngine::LoadMap, which is why RegisterLoadMapPostHook never fires on map transitions — it fired fine on the initial load from the main menu, masking the bug.

The real fix is RegisterInitGameStatePostHook, which fires after seamless travel completes and the new world is fully initialized. That's now the primary hook, with RegisterLoadMapPostHook kept as a fallback for the initial non-seamless load only.

I also added a LastLoadedWorldAddr guard that compares the memory address of the world object — this prevents double-loading when both hooks happen to fire on the same load event, and also provides a reliable way to detect "did the world actually change" rather than just blindly calling LoadMods every time either hook fires.

To confirm this is working: after installing, open the UE4SS console window while playing. When you transition maps you should see RegisterInitGameStatePostHook fired. followed by New world detected and the mod loading lines. If you instead see World unchanged, skipping reload that means the hook fired but the world address matched — which would indicate a different problem (the world object itself not being recreated), and we'd need a different strategy."