Ardour apparently always calls `effMainsChanged()` with a value argument
of 0 when unloading the plugin, regardless of whether it has actually
initialized audio processing before that point.
These only show up during unity builds, and they originate from
Boost.Container's small vector. The compiler's diagnostic also doesn't
make any sense here so it's probably just a weird GCC thing.
The sizes were wrong, and Blue Cat Audio's VST3 plugins seem to use the
upper bits to store the channel configuration, which thus got read out
incorrectly.
In the same way as 50c25c1cf0 did it for
VST2 plugins. Input and output audio data is now stored in a shared
memory buffer instead of being sent over the sockets. This reduces the
bridging overhead to a minimum since copying data was the most expensive
operation we were doing and we now only need to copy the entire buffer
once per processing cycle.
We now use shared memory to store the input and output audio buffers.
This means that we have to copy less data every processing cycle, since
a single copy to and a single copy from the shared memory object
suffices now. This should reduce the DSP load for VST2
plugins (especially when used in a plugin group) marginally to
significantly depending on the plugins used and the system
configuration.
Bundle all serialization function with the structs whenever possible to
simplify the serialization function, and add `Foo::Response` types so we
can make the `passthrough_event()` function slightly more type safe.
Every DAW will just send all events in one go (and I think that's the
only way you should do it, but the VST2 spec is a bit leaky so who
knows). It wouldn't make much sense to preallocate more capacity,
because when DAWs do send all of those events individually they might
end up sending more than four of these anyways.
This could prevent resizeable plugins from being resizeable in Ardour if
the initialized timestamp just happened to be greater than the current
time, since the returned result would then likely be some invalid value.
Instead of the parent Window. Tracktion Waveform does some weird things
with its VST2 editor embedding, so with the old approach this would
cause mouse clicks to be offset 27 pixels vertically and one pixel
horizontally.
Robbert van der Helm