leilei-
commented
8 years ago Exploring using Jedi Academy's code which uses a multitexture combine on a projected dynamic light to achieve the effect, it works but it also has issues with detail textures, causing it to combine with the detail instead, making washed out textures.
Jedi Academy has a way of doing this and is open source, but under the GPLv2 (with no later version) so that may be incompatible.
Earlier Q3Tests also had a way of doing this by the old Q2-ish way of updating the lightmap, but I think this is all torn out on the source release anyway and it's unlikely that Carmack has kept an archive of the older code and it's also legally unlikely he can clear it for release anyhow.