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.SoundIo/Native/libsoundio/SoundIOChannelLayout.cs

@@ -0,0 +1,116 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+
+namespace SoundIOSharp
+{
+    public struct SoundIOChannelLayout
+    {
+        public static int BuiltInCount
+        {
+            get { return Natives.soundio_channel_layout_builtin_count(); }
+        }
+
+        public static SoundIOChannelLayout GetBuiltIn(int index)
+        {
+            return new SoundIOChannelLayout(Natives.soundio_channel_layout_get_builtin(index));
+        }
+
+        public static SoundIOChannelLayout GetDefault(int channelCount)
+        {
+            var handle = Natives.soundio_channel_layout_get_default(channelCount);
+
+            return new SoundIOChannelLayout (handle);
+        }
+
+        public static SoundIOChannelId ParseChannelId(string name)
+        {
+            var ptr = Marshal.StringToHGlobalAnsi(name);
+
+            try 
+            {
+                return (SoundIOChannelId)Natives.soundio_parse_channel_id(ptr, name.Length);
+            }
+            finally
+            {
+                Marshal.FreeHGlobal(ptr);
+            }
+        }
+
+        // instance members
+
+        internal SoundIOChannelLayout(Pointer<SoundIoChannelLayout> handle)
+        {
+            this.handle = handle;
+        }
+
+        readonly Pointer<SoundIoChannelLayout> handle;
+
+        public bool IsNull
+        {
+            get { return handle.Handle == IntPtr.Zero; }
+        }
+
+        internal IntPtr Handle
+        {
+            get { return handle; }
+        }
+
+        public int ChannelCount
+        {
+            get { return IsNull ? 0 : Marshal.ReadInt32((IntPtr)handle + channel_count_offset); }
+        }
+
+        static readonly int channel_count_offset = (int)Marshal.OffsetOf<SoundIoChannelLayout>("channel_count");
+
+        public string Name
+        {
+            get { return IsNull ? null : Marshal.PtrToStringAnsi(Marshal.ReadIntPtr((IntPtr)handle + name_offset)); }
+        }
+
+        static readonly int name_offset = (int)Marshal.OffsetOf<SoundIoChannelLayout>("name");
+
+        public IEnumerable<SoundIOChannelId> Channels
+        {
+            get
+            {
+                if (IsNull) yield break;
+
+                for (int i = 0; i < 24; i++)
+                {
+                    yield return (SoundIOChannelId)Marshal.ReadInt32((IntPtr)handle + channels_offset + sizeof(SoundIoChannelId) * i);
+                }
+            }
+        }
+
+        static readonly int channels_offset = (int)Marshal.OffsetOf<SoundIoChannelLayout>("channels");
+
+        public override bool Equals(object other)
+        {
+            if (!(other is SoundIOChannelLayout)) return false;
+
+            var s = (SoundIOChannelLayout) other;
+
+            return handle == s.handle || Natives.soundio_channel_layout_equal(handle, s.handle);
+        }
+
+        public override int GetHashCode()
+        {
+            return handle.GetHashCode();
+        }
+
+        public string DetectBuiltInName()
+        {
+            if (IsNull) throw new InvalidOperationException();
+
+            return Natives.soundio_channel_layout_detect_builtin(handle) ? Name : null;
+        }
+
+        public int FindChannel(SoundIOChannelId channel)
+        {
+            if (IsNull) throw new InvalidOperationException();
+
+            return Natives.soundio_channel_layout_find_channel(handle, (SoundIoChannelId)channel);
+        }
+    }
+}