After 16 years, The Dark Mod finally has guards as perceptive as in Thief: 'The days of seeing knocked-out AI in the middle of a bright spotlight get ignored are over'

Over the years, The Dark Mod has done a fine job at providing a Thief-like experience in the absence of a proper new entry in the series (there was the 2014 reboot, yet while I like it more than most, ultimately it didn't live up to the series' reputation). Originally launched in 2009 as a total conversion to Doom 3, The Dark Mod was rereleased as a standalone entity in 2013, and has received consistent updates since.

The latest update, which released on Thursday, is not only the most substantial in a while, but it also makes some transformative changes to how The Dark Mod functions. At the heart of this is a rework to guard AI which, finally, makes them as perceptive as in the game which inspired it.

Understanding this change requires some context, dutifully provided on the update's ModDB page by veteran dark modder nbohr1more. "When id Software released the Doom 3 modding SDK, The Dark Mod team saw the potential for something more than a multi-player cops vs robbers game like Thievery UT," he explains. "One of the first things the team did was to investigate how a light-gem system could be implemented. Having a good way for both the player and AI to know when the player is visible to others is a crucial part of the Thief experience."

The Dark Mod team was able to recreate a light-gem system in the Doom 3 engine, but the result was incredibly performance intensive, to the point where it could cut the framerate in half. "Obviously, we could not afford to run the light-gem render for every object or body the AI might see so it was decided that the AI would do a more simplified light-gem calculation for things other than the player." Nbohr1more points out. "This was far cheaper than rendering the whole scene but heavily impacted accuracy. Many solutions were proposed to improve things but a solution evaded us for years."

In other words, the Dark Mod's guards have basically been wandering around half-blind for 16 years. According to nbohr1more, this has now been rectified using a "stochastic sampler model" which can "build a running average" of how illuminated individual entities are. "Now all AI and loot entities (etc) essentially have their own light-gem and it performs excellently!" he writes. "The days of seeing knocked-out AI in the middle of a bright spotlight get ignored are over."

More perceptive AI isn't the only change the 2.13 update makes. The update also adds support for parallax occlusion mapping, which nbohr1more says offers a "quantum leap in perceived geometric detail." There's a video showing this off, and I have to say, those ceilings are pretty snazzy. Not quite Dishonored snazzy, but not too far off. Other graphics enhancements include bettwe water reflections, and volumetric lights and particles appearing in mirrors.

Elsewhere, mission management has been adjusted so that both the mission list and in-game downloader " now have a search filter window that follows modern conventions of reducing the listed items as each new letter eliminates a possible matching mission name", while the mod's bespoke training mission has been changed so it covers mechanics added between the original launch and its standalone release. Finally and most importantly, the update fixes the "broken behaviours" of drunk guard AI, which no self-respecting Thief aspirant is complete without.

You can download The Dark Mod, complete with the 2.13 update, here. Despite the lack of official support for the series, Thief fans have been eating well of late. 2023's unofficial campaign The Black Parade features some of the best, most ambitious Thief missions I've ever skulked through, while Victorian-gothic sneak 'em up Gloomwood continues to shape up as a worthy spiritual successor. Oh, and let's not forget Warren Spector's upcoming multiplayer spin on the concept, the hugely exciting Thick as Thieves.