Warning
I stopped at trying to get this all working. Pysound has a lot of considerations for hooking it up in the same thread, It might be usable as a start to some of these ideas, but the sound is very crackly on a pi. I have moved on to making native puredata extensions in pipd and just ignoring the python part (I can make a GUI in Gem or whatever.)
The idea with this is that you can load puredata patches, headless, that can interact with pi GPIO using simple messages.
You can set your hardware interface, by using CLI flags (run pipdloader --help.)
The options stack, so if you wanted lots of IO and to add to the lib-dir:
pipdloader -l lib -l ~/pd -i 6 -i 7 -i 8 -o 9 -o 10 demo/demo.pd
results in:
file='demo/demo.pd'
input=[6, 7, 8]
output=[9, 10]
oled=False
rotary=None
lib=['lib', '/home/pi/pd']
In order to run it, you will need some dependencies. You can install themn with setup.sh or just have a look at what it installs, and do it however you like.
All messages are routed through _host and _patch, and the host program isn't even needed, so you can can dev with demo/emulator.pd open (use plugdata, as it has some extended stuff, like knobs/buttons in it) and no hardware or python is required.