Haydn: Part 1 (#2007)

* Haydn: Part 1

Based on my reverse of audio 11.0.0.

As always, core implementation under LGPLv3 for the same reasons as for Amadeus.

This place the bases of a more flexible audio system while making audout & audin accurate.

This have the following improvements:
- Complete reimplementation of audout and audin.
- Audin currently only have a dummy backend.
- Dramatically reduce CPU usage by up to 50% in common cases (SoundIO and OpenAL).
- Audio Renderer now can output to 5.1 devices when supported.
- Audio Renderer init its backend on demand instead of keeping two up all the time.
- All backends implementation are now in their own project.
- Ryujinx.Audio.Renderer was renamed Ryujinx.Audio and was refactored because of this.

As a note, games having issues with OpenAL haven't improved and will not
because of OpenAL design (stopping when buffers finish playing causing
possible audio "pops" when buffers are very small).

* Update for latest hexkyz's edits on Switchbrew

* audren: Rollback channel configuration changes

* Address gdkchan's comments

* Fix typo in OpenAL backend driver

* Address last comments

* Fix a nit

* Address gdkchan's comments

Ryujinx.Audio.Backends.OpenAL/OpenALHardwareDeviceDriver.cs

@@ -0,0 +1,170 @@
+using OpenTK.Audio;
+using Ryujinx.Audio.Common;
+using Ryujinx.Audio.Integration;
+using Ryujinx.Memory;
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using static Ryujinx.Audio.Integration.IHardwareDeviceDriver;
+
+namespace Ryujinx.Audio.Backends.OpenAL
+{
+    public class OpenALHardwareDeviceDriver : IHardwareDeviceDriver
+    {
+        private object _lock = new object();
+
+        private AudioContext _context;
+        private ManualResetEvent _updateRequiredEvent;
+        private List<OpenALHardwareDeviceSession> _sessions;
+        private bool _stillRunning;
+        private Thread _updaterThread;
+
+        public OpenALHardwareDeviceDriver()
+        {
+            _context = new AudioContext();
+            _updateRequiredEvent = new ManualResetEvent(false);
+            _sessions = new List<OpenALHardwareDeviceSession>();
+
+            _stillRunning = true;
+            _updaterThread = new Thread(Update)
+            {
+                Name = "HardwareDeviceDriver.OpenAL"
+            };
+
+            _updaterThread.Start();
+        }
+
+        public static bool IsSupported
+        {
+            get
+            {
+                try
+                {
+                    return AudioContext.AvailableDevices.Count > 0;
+                }
+                catch
+                {
+                    return false;
+                }
+            }
+        }
+
+        public IHardwareDeviceSession OpenDeviceSession(Direction direction, IVirtualMemoryManager memoryManager, SampleFormat sampleFormat, uint sampleRate, uint channelCount)
+        {
+            if (channelCount == 0)
+            {
+                channelCount = 2;
+            }
+
+            if (sampleRate == 0)
+            {
+                sampleRate = Constants.TargetSampleRate;
+            }
+
+            if (direction != Direction.Output)
+            {
+                throw new ArgumentException($"{direction}");
+            }
+            else if (!SupportsChannelCount(channelCount))
+            {
+                throw new ArgumentException($"{channelCount}");
+            }
+
+            lock (_lock)
+            {
+                OpenALHardwareDeviceSession session = new OpenALHardwareDeviceSession(this, memoryManager, sampleFormat, sampleRate, channelCount);
+
+                _sessions.Add(session);
+
+                return session;
+            }
+        }
+
+        internal void Unregister(OpenALHardwareDeviceSession session)
+        {
+            lock (_lock)
+            {
+                _sessions.Remove(session);
+            }
+        }
+
+        public ManualResetEvent GetUpdateRequiredEvent()
+        {
+            return _updateRequiredEvent;
+        }
+
+        private void Update()
+        {
+            while (_stillRunning)
+            {
+                bool updateRequired = false;
+
+                lock (_lock)
+                {
+                    foreach (OpenALHardwareDeviceSession session in _sessions)
+                    {
+                        if (session.Update())
+                        {
+                            updateRequired = true;
+                        }
+                    }
+                }
+
+                if (updateRequired)
+                {
+                    _updateRequiredEvent.Set();
+                }
+
+                // If it's not slept it will waste cycles.
+                Thread.Sleep(10);
+            }
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                lock (_lock)
+                {
+                    _stillRunning = false;
+                    _updaterThread.Join();
+
+                    // Loop against all sessions to dispose them (they will unregister themself)
+                    while (_sessions.Count > 0)
+                    {
+                        OpenALHardwareDeviceSession session = _sessions[0];
+
+                        session.Dispose();
+                    }
+                }
+
+                _context.Dispose();
+            }
+        }
+
+        public bool SupportsSampleRate(uint sampleRate)
+        {
+            return true;
+        }
+
+        public bool SupportsSampleFormat(SampleFormat sampleFormat)
+        {
+            return true;
+        }
+
+        public bool SupportsChannelCount(uint channelCount)
+        {
+            return channelCount == 1 || channelCount == 2 || channelCount == 6;
+        }
+
+        public bool SupportsDirection(Direction direction)
+        {
+            return direction == Direction.Output;
+        }
+    }
+}