The main problem was that the volume of the mixer wasn't savestated.
The volume is typically 0 at the beginning of a game, so loading a
savestate at the beginning of a game would lead to silent DTK audio.
I also added savestating to StreamADPCM.cpp.
A bunch of changes, looks mainly like bug fixes and code cleanup.
Notable changes:
- `cubeb_get_min_latency`'s signature was changed to take params via
pointer, requiring Dolphin code to be tweaked in two places.
- A fix for kinetiknz/cubeb#320, as reported by @shuffle2
- Fixed build on FreeBSD (kinetiknz/cubeb#344), as contributed by @endrift
The class NonCopyable is, like the name says, supposed to disallow
copying. But should it allow moving?
For a long time, NonCopyable used to not allow moving. (It declared
a deleted copy constructor and assigment operator without declaring
a move constructor and assignment operator, making the compiler
implicitly delete the move constructor and assignment operator.)
That's fine if the classes that inherit from NonCopyable don't need
to be movable or if writing the move constructor and assignment
operator by hand is fine, but that's not the case for all classes,
as I discovered when I was working on the DirectoryBlob PR.
Because of that, I decided to make NonCopyable movable in c7602cc,
allowing me to use NonCopyable in DirectoryBlob.h. That was however
an unfortunate decision, because some of the classes that inherit
from NonCopyable have incorrect behavior when moved by default-
generated move constructors and assignment operators, and do not
explicitly delete the move constructors and assignment operators,
relying on NonCopyable being non-movable.
So what can we do about this? There are four solutions that I can
think of:
1. Make NonCopyable non-movable and tell DirectoryBlob to suck it.
2. Keep allowing moving NonCopyable, and expect that classes that
don't support moving will delete the move constructor and
assignment operator manually. Not only is this inconsistent
(having classes disallow copying one way and disallow moving
another way), but deleting the move constructor and assignment
operator manually is too easy to forget compared to how tricky
the resulting problems are.
3. Have one "MovableNonCopyable" and one "NonMovableNonCopyable".
It works, but it feels rather silly...
4. Don't have a NonCopyable class at all. Considering that deleting
the copy constructor and assignment operator only takes two lines
of code, I don't see much of a reason to keep NonCopyable. I
suppose that there was more of a point in having NonCopyable back
in the pre-C++11 days, when it wasn't possible to use "= delete".
I decided to go with the fourth one (like the commit title says).
The implementation of the commit is fairly straight-forward, though
I would like to point out that I skipped adding "= delete" lines
for classes whose only reason for being uncopyable is that they
contain uncopyable classes like File::IOFile and std::unique_ptr,
because the compiler makes such classes uncopyable automatically.
It seems to make no difference besides allowing lower latencies and more
stability on hardware OpenAL cards. Maybe the Wait() call waits for too
long, causing buffers underruns.
Before these changes each value of latency were actually 5ms, with a
minimum latency of ~10 ms. If it was set to 4 ms on the UI, the actual
latency was 10 + 5 * 4 = 30 ms.
Now 30 ms on the UI means 30 ms on the backend.
OpenALStream was querying the backend for AL_EXT_float32 support (which
suceeds), but AL_FORMAT_STEREO_FLOAT32 was defined incorrectly.
Also changes OpenALStream to query for AL_EXT_MCFORMATS (multichannel
support) rather than hard-coding that it doesn't work on macOS.
Fixes an error with the CoreAudio backend, which apparently doesn't
allow you to set the volume before starting the stream:
```
59:31:087 AudioCommon/CoreAudioSoundStream.cpp:97 E[Audio]: error setting volume
```
This shouldn't cause any problems with other backends, since the mixer
starts with silence anyways.
