start reimplementing streaming audio on voice API

src/Audio/AudioDevice.cs

@@ -159,6 +159,8 @@ namespace MoonWorks.Audio
 			previousTickTime = TickStopwatch.Elapsed.Ticks;
 			float elapsedSeconds = (float) tickDelta / System.TimeSpan.TicksPerSecond;
 
+			// TODO: call an Update on all active voices
+
 			for (var i = autoUpdateStreamingSoundReferences.Count - 1; i >= 0; i -= 1)
 			{
 				var streamingSound = autoUpdateStreamingSoundReferences[i];
@@ -206,6 +208,8 @@ namespace MoonWorks.Audio
 			FAudio.FAudio_CommitChanges(Handle, syncGroup);
 		}
 
+		// TODO: is pooling SourceVoices generically a good idea? there are a lot of different kinds
+
 		/// <summary>
 		/// Obtains an appropriate source voice from the voice pool.
 		/// </summary>

src/Audio/SourceVoice.cs

@@ -160,11 +160,6 @@ namespace MoonWorks.Audio
 			);
 		}
 
-		public void Submit(StreamingSound streamingSound)
-		{
-
-		}
-
 		/// <summary>
 		/// Designates that this source voice will return to the voice pool once all its buffers are exhausted.
 		/// </summary>

src/Audio/StreamingSound.cs

@@ -165,7 +165,7 @@ namespace MoonWorks.Audio
 			queuedBufferCount = 0;
 		}
 
-		protected unsafe void AddBuffer()
+		public unsafe void AddBuffer()
 		{
 			var buffer = buffers[nextBufferIndex];
 			nextBufferIndex = (nextBufferIndex + 1) % BUFFER_COUNT;

src/Audio/StreamingVoice.cs

@@ -0,0 +1,92 @@
+using System;
+
+namespace MoonWorks.Audio
+{
+	public abstract class StreamingVoice : SourceVoice
+	{
+		private const int BUFFER_COUNT = 3;
+		private readonly IntPtr[] buffers;
+		private int nextBufferIndex = 0;
+		private uint BufferSize;
+
+		public bool Loop { get; set; }
+
+		public StreamingVoice(AudioDevice device, Format format, uint bufferSize) : base(device, format)
+		{
+			BufferSize = bufferSize;
+		}
+
+		internal unsafe void Update()
+		{
+			lock (StateLock)
+			{
+				if (!IsDisposed)
+				{
+					if (State != SoundState.Playing)
+					{
+						return;
+					}
+
+					QueueBuffers();
+				}
+			}
+		}
+
+		protected void QueueBuffers()
+		{
+			var buffersQueued = BuffersQueued;
+			for (int i = 0; i < BUFFER_COUNT - buffersQueued; i += 1)
+			{
+				AddBuffer();
+			}
+		}
+
+		protected unsafe void AddBuffer()
+		{
+			var buffer = buffers[nextBufferIndex];
+			nextBufferIndex = (nextBufferIndex + 1) % BUFFER_COUNT;
+
+			FillBuffer(
+				(void*) buffer,
+				(int) BufferSize,
+				out int filledLengthInBytes,
+				out bool reachedEnd
+			);
+
+			if (filledLengthInBytes > 0)
+			{
+				var buf = new FAudio.FAudioBuffer
+				{
+					AudioBytes = (uint) filledLengthInBytes,
+					pAudioData = buffer,
+					PlayLength = (
+						(uint) (filledLengthInBytes /
+						Format.Channels /
+						(uint) (Format.BitsPerSample / 8))
+					)
+				};
+
+				Submit(buf);
+			}
+
+			if (reachedEnd)
+			{
+				/* We have reached the end of the data, what do we do? */
+				if (Loop)
+				{
+					SeekStart();
+					AddBuffer();
+				}
+			}
+		}
+
+		protected unsafe abstract void FillBuffer(
+			void* buffer,
+			int bufferLengthInBytes, /* in bytes */
+			out int filledLengthInBytes, /* in bytes */
+			out bool reachedEnd
+		);
+
+		protected abstract void SeekStart();
+	}
+}