change AudioDevice to run on a background thread

src/Audio/AudioDevice.cs

@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Runtime.InteropServices;
+using System.Threading;
 
 namespace MoonWorks.Audio
 {
@@ -29,10 +29,17 @@ namespace MoonWorks.Audio
 		private readonly List<WeakReference<AudioResource>> resources = new List<WeakReference<AudioResource>>();
 		private readonly List<WeakReference<StreamingSound>> streamingSounds = new List<WeakReference<StreamingSound>>();
 
+		private const int Step = 200;
+		private TimeSpan UpdateInterval;
+		private Thread Thread;
+		private AutoResetEvent WakeSignal;
+
 		private bool IsDisposed;
 
 		public unsafe AudioDevice()
 		{
+			UpdateInterval = TimeSpan.FromTicks(TimeSpan.TicksPerSecond / Step);
+
 			FAudio.FAudioCreate(out var handle, 0, FAudio.FAUDIO_DEFAULT_PROCESSOR);
 			Handle = handle;
 
@@ -105,9 +112,26 @@ namespace MoonWorks.Audio
 				SpeedOfSound,
 				Handle3D
 			);
+
+			Logger.LogInfo("Setting up audio thread...");
+			WakeSignal = new AutoResetEvent(true);
+
+			Thread = new Thread(ThreadMain);
+			Thread.IsBackground = true;
+			Thread.Start();
 		}
 
-		internal void Update()
+		private void ThreadMain()
+		{
+			while (!IsDisposed)
+			{
+				ThreadMainTick();
+
+				WakeSignal.WaitOne(UpdateInterval);
+			}
+		}
+
+		private void ThreadMainTick()
 		{
 			for (var i = streamingSounds.Count - 1; i >= 0; i--)
 			{
@@ -123,6 +147,11 @@ namespace MoonWorks.Audio
 			}
 		}
 
+		internal void WakeThread()
+		{
+			WakeSignal.Set();
+		}
+
 		public void SyncPlay()
 		{
 			FAudio.FAudio_CommitChanges(Handle, 1);

src/Game.cs

@@ -168,9 +168,8 @@ namespace MoonWorks
 				while (accumulatedUpdateTime >= Timestep)
 				{
 					Inputs.Update();
-					AudioDevice.Update();
-
 					Update(Timestep);
+					AudioDevice.WakeThread();
 
 					accumulatedUpdateTime -= Timestep;
 				}