[LAD] Realtime inter-thread communication

[Spencer Jackson]

> The generic solution for cases like this is a lock-free ringbuffer.

I've also used the jack ringbuffer for this and it was easy enough.
Not that my work is a reference implementation but you can see how I
take it from a usb callback to the jack process thread here:
https://github.com/rbdrum2midi/rbdrum2midi/blob/dev/src/jackdriver.c#L281
(The process code is above at line 198, note that most of this was
lifted from the jack_keyboard source)

>> I've also looked into LV2. If I implemented the synthesizer as LV2
>> plugin, I would get around having to solve the inter-thread
>> communication problem because it's the plugin host's responsibility.
>> But to be honest I've found this API to be a bit intimidating and I'm
>> not familiar with any LV2 host that would allow me to test such a
>> plugin. Any recommendations? Ardour?
>
> jalv, Carla, QTractor, Ardour..
>
> A LV2 simple synth example can be found at http://lv2plug.in/book/#_sampler

I like jalv for debugging because its quite simple and quick to load.
I can run it with gdb and valgrind/callgrind without any trouble. I've
found it important to test in other hosts too though but only once its
working in jalv.

FWIW I hope you do make an LV2 plugin version as I rarely use
standalone synths these days. Again perhaps not the best
implementation but it is a fully independently coded one for an LV2
synth:
https://github.com/ssj71/infamousPlugins/blob/master/src/casynth/casynth.c#L188
It always helps me to have several references to understand
implementation details.

If you have any questions about my code I've linked you are welcome to
ask. Also, LV2 has a ML and IRC channel and I'll be happy to offer any
advice or support there that I can too.

Good luck
_Spencer