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

1 files changed, 140 insertions, 0 deletions

diff --git a/Ryujinx.Audio/Backends/CompatLayer/CompatLayerHardwareDeviceSession.cs b/Ryujinx.Audio/Backends/CompatLayer/CompatLayerHardwareDeviceSession.cs
new file mode 100644
index 00000000..493d682f
--- /dev/null
+++ b/Ryujinx.Audio/Backends/CompatLayer/CompatLayerHardwareDeviceSession.cs
@@ -0,0 +1,140 @@
+//
+// Copyright (c) 2019-2021 Ryujinx
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+using Ryujinx.Audio.Backends.Common;
+using Ryujinx.Audio.Common;
+using System;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Audio.Backends.CompatLayer
+{
+    class CompatLayerHardwareDeviceSession : HardwareDeviceSessionOutputBase
+    {
+        private HardwareDeviceSessionOutputBase _realSession;
+        private uint _userChannelCount;
+
+        public CompatLayerHardwareDeviceSession(HardwareDeviceSessionOutputBase realSession, uint userChannelCount) : base(realSession.MemoryManager, realSession.RequestedSampleFormat, realSession.RequestedSampleRate, userChannelCount)
+        {
+            _realSession = realSession;
+            _userChannelCount = userChannelCount;
+        }
+
+        public override void Dispose()
+        {
+            _realSession.Dispose();
+        }
+
+        public override ulong GetPlayedSampleCount()
+        {
+            return _realSession.GetPlayedSampleCount();
+        }
+
+        public override float GetVolume()
+        {
+            return _realSession.GetVolume();
+        }
+
+        public override void PrepareToClose()
+        {
+            _realSession.PrepareToClose();
+        }
+
+        public override void QueueBuffer(AudioBuffer buffer)
+        {
+            _realSession.QueueBuffer(buffer);
+        }
+
+        public override bool RegisterBuffer(AudioBuffer buffer, byte[] samples)
+        {
+            if (RequestedSampleFormat != SampleFormat.PcmInt16)
+            {
+                throw new NotImplementedException("Downmixing formats other than PCM16 is not supported.");
+            }
+
+            if (samples == null)
+            {
+                return false;
+            }
+
+            short[] downmixedBufferPCM16;
+
+            ReadOnlySpan<short> samplesPCM16 = MemoryMarshal.Cast<byte, short>(samples);
+
+            if (_userChannelCount == 6)
+            {
+                downmixedBufferPCM16 = Downmixing.DownMixSurroundToStereo(samplesPCM16);
+
+                if (_realSession.RequestedChannelCount == 1)
+                {
+                    downmixedBufferPCM16 = Downmixing.DownMixStereoToMono(downmixedBufferPCM16);
+                }
+            }
+            else if (_userChannelCount == 2 && _realSession.RequestedChannelCount == 1)
+            {
+                downmixedBufferPCM16 = Downmixing.DownMixStereoToMono(samplesPCM16);
+            }
+            else
+            {
+                throw new NotImplementedException($"Downmixing from {_userChannelCount} to {_realSession.RequestedChannelCount} not implemented.");
+            }
+
+            byte[] downmixedBuffer = MemoryMarshal.Cast<short, byte>(downmixedBufferPCM16).ToArray();
+
+            AudioBuffer fakeBuffer = new AudioBuffer
+            {
+                BufferTag = buffer.BufferTag,
+                DataPointer = buffer.DataPointer,
+                DataSize  = (ulong)downmixedBuffer.Length
+            };
+
+            bool result = _realSession.RegisterBuffer(fakeBuffer, downmixedBuffer);
+
+            if (result)
+            {
+                buffer.Data = fakeBuffer.Data;
+                buffer.DataSize = fakeBuffer.DataSize;
+            }
+
+            return result;
+        }
+
+        public override void SetVolume(float volume)
+        {
+            _realSession.SetVolume(volume);
+        }
+
+        public override void Start()
+        {
+            _realSession.Start();
+        }
+
+        public override void Stop()
+        {
+            _realSession.Stop();
+        }
+
+        public override void UnregisterBuffer(AudioBuffer buffer)
+        {
+            _realSession.UnregisterBuffer(buffer);
+        }
+
+        public override bool WasBufferFullyConsumed(AudioBuffer buffer)
+        {
+            return _realSession.WasBufferFullyConsumed(buffer);
+        }
+    }
+}