After doing a little more reading up on the Opus codec, it turns out
that the multistream API that is part of libopus can handle regular
packets. Regular packets are just a degenerate case of multistream Opus
packets, and all that's necessary is to pass the number of streams as 1
and provide a basic channel mapping, then everything works fine for
that case.
This allows us to get rid of the need to use both APIs in the future
when implementing multistream variants in a follow-up PR, greatly
simplifying the code that needs to be written.
This will be utilized by more than just that class in the future. This
also renames it from OpusHeader to OpusPacketHeader to be more specific
about what kind of header it is.
Places all error codes in an easily includable header.
This also corrects the unsupported error code (I accidentally used the
hex value when I meant to use the decimal one).
This currently has the same behavior as the regular
OpenAudioRenderer API function, so we can just move the code within
OpenAudioRenderer to an internal function that both service functions
call.
This service function appears to do nothing noteworthy on the switch.
All it does at the moment is either return an error code or abort the
system. Given we obviously don't want to kill the system, we just opt
for always returning the error code.
Provides names for previously unknown entries (aside from the two u8
that appear to be padding bytes, and a single word that also appears
to be reserved or padding).
This will be useful in subsequent changes when unstubbing behavior related
to the audio renderer services.
Gets rid of the largest set of mutable global state within the core.
This also paves a way for eliminating usages of GetInstance() on the
System class as a follow-up.
Note that no behavioral changes have been made, and this simply extracts
the functionality into a class. This also has the benefit of making
dependencies on the core timing functionality explicit within the
relevant interfaces.
This functions almost identically to DecodeInterleavedWithPerfOld,
however this function also has the ability to reset the decoder context.
This is documented as a potentially desirable thing in the libopus
manual in some circumstances as it says for the OPUS_RESET_STATE ctl:
"This should be called when switching streams in order to prevent the
back to back decoding from giving different result from one at a time
decoding."
Preserves the meaning/type-safetiness of the stream state instead of
making it an opaque u32. This makes it usable for other things outside
of the service HLE context.
When a destructor isn't defaulted into a cpp file, it can cause the use
of forward declarations to seemingly fail to compile for non-obvious
reasons. It also allows inlining of the construction/destruction logic
all over the place where a constructor or destructor is invoked, which
can lead to code bloat. This isn't so much a worry here, given the
services won't be created and destroyed frequently.
The cause of the above mentioned non-obvious errors can be demonstrated
as follows:
------- Demonstrative example, if you know how the described error happens, skip forwards -------
Assume we have the following in the header, which we'll call "thing.h":
\#include <memory>
// Forward declaration. For example purposes, assume the definition
// of Object is in some header named "object.h"
class Object;
class Thing {
public:
// assume no constructors or destructors are specified here,
// or the constructors/destructors are defined as:
//
// Thing() = default;
// ~Thing() = default;
//
// ... Some interface member functions would be defined here
private:
std::shared_ptr<Object> obj;
};
If this header is included in a cpp file, (which we'll call "main.cpp"),
this will result in a compilation error, because even though no
destructor is specified, the destructor will still need to be generated by
the compiler because std::shared_ptr's destructor is *not* trivial (in
other words, it does something other than nothing), as std::shared_ptr's
destructor needs to do two things:
1. Decrement the shared reference count of the object being pointed to,
and if the reference count decrements to zero,
2. Free the Object instance's memory (aka deallocate the memory it's
pointing to).
And so the compiler generates the code for the destructor doing this inside main.cpp.
Now, keep in mind, the Object forward declaration is not a complete type. All it
does is tell the compiler "a type named Object exists" and allows us to
use the name in certain situations to avoid a header dependency. So the
compiler needs to generate destruction code for Object, but the compiler
doesn't know *how* to destruct it. A forward declaration doesn't tell
the compiler anything about Object's constructor or destructor. So, the
compiler will issue an error in this case because it's undefined
behavior to try and deallocate (or construct) an incomplete type and
std::shared_ptr and std::unique_ptr make sure this isn't the case
internally.
Now, if we had defaulted the destructor in "thing.cpp", where we also
include "object.h", this would never be an issue, as the destructor
would only have its code generated in one place, and it would be in a
place where the full class definition of Object would be visible to the
compiler.
---------------------- End example ----------------------------
Given these service classes are more than certainly going to change in
the future, this defaults the constructors and destructors into the
relevant cpp files to make the construction and destruction of all of
the services consistent and unlikely to run into cases where forward
declarations are indirectly causing compilation errors. It also has the
plus of avoiding the need to rebuild several services if destruction
logic changes, since it would only be necessary to recompile the single
cpp file.
As means to pave the way for getting rid of global state within core,
This eliminates kernel global state by removing all globals. Instead
this introduces a KernelCore class which acts as a kernel instance. This
instance lives in the System class, which keeps its lifetime contained
to the lifetime of the System class.
This also forces the kernel types to actually interact with the main
kernel instance itself instead of having transient kernel state placed
all over several translation units, keeping everything together. It also
has a nice consequence of making dependencies much more explicit.
This also makes our initialization a tad bit more correct. Previously we
were creating a kernel process before the actual kernel was initialized,
which doesn't really make much sense.
The KernelCore class itself follows the PImpl idiom, which allows
keeping all the implementation details sealed away from everything else,
which forces the use of the exposed API and allows us to avoid any
unnecessary inclusions within the main kernel header.
As we're not handling any anything about the revision data for GetAudioDeviceServiceWithRevisionInfo, it's currently marked as stubbed. However for games this shouldn't affect the result. Proper revision info would be more for homebrew.
GetAudioRendererSampleRate is set as a "STUB" as a game could check if the sample rate it sent and the sample rate it wants don't match. Just a thought of something which could happen so keeping it as stub for the mean time
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