The Dark Mod is a seriously impressive project giving us a completely free and open source standalone Thief-like stealth game, and The Dark Mod 2.13 release is another great one.
In this release they've managed to overhaul AI vision system, which sounds lot more impressive and accurate. They go into a bit of detail on the history on why it wasn't great originally, with light previously being calculated as "either cubes or pyramids with perfect exponential falloff" but now they have "a stochastic sampler model that does regular measurements of the actual light volume pixels and builds a running average of how illuminated different entities are". The result? Light works more like actual light with their example video below:

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There's also been an overhaul to Mission Management with a new UI. It has a search filter now that "follows modern conventions of reducing the listed items as each new letter eliminates a possible matching mission name" with new sorting options. You can also now scroll the additional mission details and more.

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They've also added in Parallax Occlusion Mapping and other new graphical goodies, an improved training mission, new potions were added, new assets are available for mission builders and much more.
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