The idea behind this project is a fun one: take a big open world game and go fly FPV through it. The maker already built an FPV mod for Super Mario 64, and now GTA IV gets the same treatment through a library called libfpv. The stated goal is bigger than one title: get libfpv running inside nearly any game as a realistic FPV simulator, with more game conversions planned for the future.
How it came together is interesting. GTA IV has no source code to work from, so the maker leaned on modding tools instead, and Claude Code helped along the way. The maker calls the project vibecoded, and debugging took roughly three to four hours before things worked.
The technical details stand out. libfpv embeds Betaflight plus an engine called SimITL, while the game itself only supplies collisions and ground effect. The flight physics reportedly stay identical no matter which game runs, with SimITL credited for that, and the drone feels different near the ground, where the game's ground effect comes in. Everything is open source too, both the libfpv repo and the GTA IV FPV repo.
One open item: a technical blog article explaining how the mod was made has been promised but not published yet. Also, the audio turned out very loud before publishing, so a warning about the volume was added to the description. Headphone users, take note.