Actually, that I remember, the pitch tables that FT is somewhere in the source. I think it's closely related to some classic game's tables (I wanna say SMB).
Ideally, for the time being, you would choose your base note to tune of off (let's say rainwarrior's detuned F#0 [triangle is a transposing instrument people! :P)) and replace FT's pitch table with your custom one, and then compile FT again, this time, all your F#0's will have basically P4D (or technically, just A2 less than whatever the current FT tables define F#0 as)
It's not actually related to any classic game tables. It is standard equal temperament tuned to A440 rounded to the nearest pitch value.
There is no pitch table in code, it is generated when the playback engine is initialized. (And it'd be easy to change at runtime.)
However, I believe in the NSF export, the pitch tables are a pre-generated binary data block that is simply inserted into the exported file. It probably wouldn't be too hard to rewrite the exporter to use the current runtime pitch tables though.
Anyhow, is anyone actually interested in having a robust pitch table editor? I mean, I know people into microtonal tuning, but it's been a pretty small community in my experience. (Has anyone here actually used microtonal tuning before? Just wondering.)
That reminded me of the music from Eversion, specifically Eversion level -6. Where the music is continuously slowing down and speeding up, many of those 25 or 50 cent off notes were heard there, but you didn't mind it as much.
Myself I've written a bunch of stuff in various exotic tunings, mostly in midi form, but almost all of it got lost in a hard drive crash a while back. This tune and the semi-procedurally-generated music for a demo I made are pretty much all that remain in recorded form at the moment.
Quarter tones are actually one of my least favourite things to do with microtonality, though there are a couple of cool things you can do with them. (The close approximation to 7 and especially 11-limit just intonation is fun, and also I really like the triad where you use the quarter tone between a major and minor third.)
On the subject of microtuning, I made this command line tool for batch conversion between real frequencies and pulse-register values (intended for use with Scala). It's mostly for PPMCK users, but I might add the ability to output Famitracker detune values at some point.
I don't think the function you speak of exists in Famitracker. If you're talking about tuning the notes manually, of course you can do that, but it's faster to calculate the values automatically, especially if you're working with microtonal scales which have more than 12 notes, or which don't wraparound at a 2:1 ratio.
This makes the writing process easier in PPMCK, especially if you have a program like PhraseExpress that can assign @n commands to keystrokes. It's just about as fast as typing normal notes. I plan on using this for some weird as hell MMC5/VRC6 tunes.
True, but you wouldn't be able to hear what you're composing until after it's retuned.
What would be nice is if jsr added the ability to make a custom pitch table in Famitracker and save it as a tuning, similar to OpenMPT's custom tuning in MPTM mode.