Or technically, two, since the group bridge also does the same loop. We
no longer need special handling for VST2 and VST3 plugins, so we can
simplify things a bit here.
This is in some cases needed to get decent performance in REAPER, as
REAPER seems to query this information (which cannot change without the
plugin requesting a restart) four times per second.
In commit 9788f21e0e we changed the input
focus grabbing to only grab focus once per event cycle, because
otherwise Bitwig would fight over who was getting focus. This is a bit
hacky, and with this approach you could in theory still have an
unnecessary focus grab 60 times per second (i.e. the default event
polling rate). Now we instead check the current focus target, and only
request focus when it's actually necessary.
It sort of goes against yabridge's principles to not do these
unnecessary `audioMasterGetTime()` calls if the plugin does that, but it
also hurts the user experience to not have this as a default.
Ever since 0bed2b7bc0 REAPER will randomly
not play back one or more audio channels for plugins that support
IPlugViewContentScaleSuport. If you return `kNotImplemented` then this
bug doesn't occur. REAPER should definitely fix this soon. With
`kResultFalse` this issue still occurs, hence this change so you can use
`vst3_no_scale` to work around this REAPER bug.
I haven't seen this cause issues myself, but it would not surprise me if
a plugin that produces a constant stream of FIXMEs would steal resources
from audio processing if the threads that are relaying those messages
are set to SCHED_FIFO.
FabFilter plugins will exchange messages that have to be handled from
the GUI thread, or they'll get stuck waiting on a synchronisation
object. This probably hurts GUI performance significantly but luckily it
only affects Ardour.
We'll periodically copy the scheduling priorities from the host's audio
threads to the Wine plugin host's audio threads. The overhead of doing
this is about 1 microsecond on my system, so doing this every cycle
really adds up. But getting the Unix epoch time and comparing some
timestamps has a neglegible overhead, so this should give you the best
of both worlds.
Next we'll do the same thing for VST3 plugins.
As suggested by @jhernberg
This is a breaking change. Old projects containing VST3 plugins running
through yabridge will no longer work without modifications. I'll write
some scripts to convert the class IDs stored in those project files soon
a migration path.
The UIDs reported by the plugin were apparently wrong, which meant that
the native Linux VST3 version of plugin X and the normal Windows VST3
version of plugin X used different class ideas than the Windows VST3
version of plugin X running through yabridge. Those things are supposed
to be compatible, so we sadly needed to make this change at some point.
It's pretty hard to find a solution that checks all of the boxes. I want
something that:
- Closes instantly when you close the editor, and in REAPER you should
be able to instantly switch between docked and floating modes
- Where there should not be a delay in user interaction when quickly
reopening the editor (or doing that switching thing in REAPER since that's
the same thing)
- Where the window manager should not try to reparent the window during
the losing process as that can cause some jarring flickering
- And, of course, there should be no weird Wine X11Drv crashes
And it should do all of that in Bitwig, REAPER, Carla, Ardour and
Renoise. Apparently it's quite the task to find an approach that checks
all the boxes there.
By directly stopping the IO context there was a chance that a task would
get cancelled outright if all stars aligned in the wrong way. Stopping
the IO context could happen between posting the task to the context and
waiting for it. This approach is much safer as we cannot drop any work
this way.
I've never seen this happen, but now this too would support deeply
nested mutual recursion just like we implemented in
`Vst3PlugViewProxyImpl`. Better safe than sorry.
On Bitwig grabbing input focus this way would trigger many more FocusIn
events, which in certain situations could cause the interface to hang
while everything was being processed.
This was a bit of a tricky one because it requires simulating mutual
recursion, but it's needed for REAPER as otherwide calls to
`IPlugFrame::resizeView()` and `IContextMenu::popup()` might cause
REAPER to segfault because its GUI is not thread safe.
Robbert van der Helm