This required rewriting the way events and parameter changes are handled
for VST3 by putting them all in a single sorted array, because we can
now no longer read directly from the host's events list because we also
need to mix these new generated MIDI CC events in with it.
This is a breaking change requiring a small change to plugin
implementations.
The reason why `Pin<&dyn Params>` was used was more as a hint to
indicate that the object must last for the plugin's lifetime, but `Pin`
doesn't enforce that. It also makes the APIs a lot more awkward.
Requiring the use of `Arc` fixes the following problems:
- When storing the params object in the wrapper, the `ParamPtr`s are
guaranteed to be stable.
- This makes it possible to access the `Params` object without acquiring
a lock on the plugin, this is very important for implementing
plugin-side preset management.
- It enforces immutability on the `Params` object.
- And of course the API is much nicer without a bunch of unsafe code to
work around Pin's limitations.
This now is a single vector with all of the information in the correct
order instead of the hashmaps and a vector. This avoids deduplication,
and it especially makes manual `Params` implementations a lot more
convenient since you can't mess up with mismatching IDs between the
methods.
To accommodate exactly this, the persistent fields methods also have a
default implementation and the trait has been marked as `unsafe` since
it's the programmer's responsibility to make sure these `ParamPtr`s will
remain valid.
This makes the API much, much nicer (especially consuming the egui
wrapper), and it also avoids having to lock the plugin instance which is
obviously very bad if the plugin is also supposed to be processing audio
on another thread.
This needs a lot of work. We need widgets that know how to deal with our
parameters, and also basic widgets for things like meters. Egui-baseview
also has a couple quirks left. Most notably it only updates when
actively moving over the GUI (which means VU meters look pretty janky)
and it randomly panics.
They can't contain any references anyways since they're default
initialized. If they don't have a 'static lifetime, then it won't be
possible to pass a trait object casted from the inner wrapper to the
plugin.
