Nightdive found 'Giant hack! Delete after E3!' comments still sitting in Thief's code decades later

Nightdive is remastering Thief: The Dark Project, and digging into Looking Glass Studio's original codebase has turned up some genuinely wild archaeological finds — including panicked developer comments from 1997 that were never cleaned up.

Nightdive software engineer Josh Dowell spoke to Digital Foundry's Retro Super Show about what the studio discovered when it got access to a "very very out of date version control repository" for the Dark Engine. The comments left by Looking Glass and Irrational Games programmers are the highlight: things like "Giant hack! Never replicate this! We must fix this before '98!" and "E3 hack! We must delete this after E3!" — and, as Dowell notes, those comments are still sitting in Thief 2's codebase untouched. Dowell also suspects the game's notoriously uneven internals come down to a mid-development team swap: most of the original crew moved to other projects, and a new team took over for the second half. Thief was shown at E3 in 1997 and was supposed to ship that same year before slipping to 1998, and the code reads like it was still being hammered into shape on the way out the door.

On the technical side, Dowell's breakdown of the Dark Engine is fascinating. He describes it as "shockingly" a clone of Quake at its rendering core — same lighting approach, same system for toggling lights on and off. But where Quake uses precomputed visibility (the engine calculates what's visible from any given spot ahead of time), the Dark Engine does that calculation live, in real-time, using a portal-based system where every doorway in a level defines what geometry can be seen through it. It's essentially doing at runtime what Quake only did during its slow precompute phase. "I can't believe they got away with it in '98," Dowell says. The result is a game whose AI, audio, and lighting still hold up — a testament to how much Looking Glass squeezed out of a rushed, comment-riddled engine.

Thief: The Dark Project Remastered doesn't have a release date yet. The project is trackable on Steam, GOG, and Epic Games Store for anyone who wants to follow its progress.