Jreetings TTLG

Due to celestial events my main musical project is on hold, in the meantime I've been making some soundtracks for games so I can challenge my abilities as a musician. It was fun to make a custom Baba Is You soundtrack for example, I learned the unorthodox ways in which Hempuli constructed his songs for the game.

I now want to make an Eric Brosius style ambient soundtrack inspired by my idea for a Black Parade/T2X style fangame that'll probably never release. I bought the official T1 OST on Bandcamp and listened to it. Then I realised that Thief doesn't have a soundtrack in the traditional sense at all, rather just ambient loops that play at different places in the level and mix into one another by happenstance during gameplay, and not by some composers' design or arrangement.

I found the Eric Brosius interview from the early 2010s, but that didn't bring me much further other than it taught me that shorter loops are better, which I agree with as I've always preferred T1's soundtrack a bit over T2's, which utilized slightly longer loops.

I've already made some good Thiefy ambient loops that fit the missions from the fangame Idea pretty well. I'm making this post to ask you guys who are much more knowledgeable than me about the game, the question being: How did they implement these loops into the game? How do I go about implementing my loops in so I can test if the soundtrack layers with in-game SFX and fits with the atmosphere? Does it have to be MIDI or can I utilize a more convenient format? How much programming knowledge is required? What online resources can you guys point to that helps explicate how this unique soundtrack was implemented?

Ad for the intro and credits songs, I can just compose a normal tune for those, so that's no problem.

Thanks in advance. If I get good enough guidance I think I could post the raw loops and completed OST on here in probably a month max. If there is any interest in the fangame Idea that I'm basing this soundtrack off of, I'll post my outline.txt for the story, characters and missions as well. Maybe it has some potential.