MoonWorks/src/Audio/SourceVoice.cs

using System;

namespace MoonWorks.Audio
{
	public class SourceVoice : SendableVoice
	{
		private Format format;
		public Format Format => format;

		protected object StateLock = new object();

		public uint BuffersQueued
		{
			get
			{
				FAudio.FAudioSourceVoice_GetState(
					Handle,
					out var state,
					FAudio.FAUDIO_VOICE_NOSAMPLESPLAYED
				);

				return state.BuffersQueued;
			}
		}

		private SoundState state;
		public SoundState State
		{
			get
			{
				if (BuffersQueued == 0)
				{
					Stop();
				}

				return state;
			}

			internal set
			{
				state = value;
			}
		}

		public delegate void OnUpdateFunc();
		public OnUpdateFunc OnUpdate; // called by AudioDevice thread

		public SourceVoice(
			AudioDevice device,
			Format format
		) : base(device, format.Channels, device.DeviceDetails.OutputFormat.Format.nChannels)
		{
			this.format = format;
			var fAudioFormat = format.ToFAudioFormat();

			 FAudio.FAudio_CreateSourceVoice(
				device.Handle,
				out var Handle,
				ref fAudioFormat,
				FAudio.FAUDIO_VOICE_USEFILTER,
				FAudio.FAUDIO_DEFAULT_FREQ_RATIO,
				IntPtr.Zero,
				IntPtr.Zero, // default sends to mastering voice!
				IntPtr.Zero
			);
		}

		public void Play(uint syncGroup = FAudio.FAUDIO_COMMIT_NOW)
		{
			lock (StateLock)
			{
				FAudio.FAudioSourceVoice_Start(Handle, 0, syncGroup);

				State = SoundState.Playing;
			}
		}

		public void Pause(uint syncGroup = FAudio.FAUDIO_COMMIT_NOW)
		{
			lock (StateLock)
			{
				FAudio.FAudioSourceVoice_Stop(Handle, 0, syncGroup);

				State = SoundState.Paused;
			}
		}

		public void ExitLoop(uint syncGroup = FAudio.FAUDIO_COMMIT_NOW)
		{
			lock (StateLock)
			{
				FAudio.FAudioSourceVoice_ExitLoop(Handle, syncGroup);
			}
		}

		public void Stop(uint syncGroup = FAudio.FAUDIO_COMMIT_NOW)
		{
			lock (StateLock)
			{
				FAudio.FAudioSourceVoice_Stop(Handle, 0, syncGroup);
				FAudio.FAudioSourceVoice_FlushSourceBuffers(Handle);

				State = SoundState.Stopped;
			}
		}

		public void SubmitBuffer(FAudio.FAudioBuffer buffer)
		{
			FAudio.FAudioSourceVoice_SubmitSourceBuffer(
				Handle,
				ref buffer,
				IntPtr.Zero
			);
		}

		// FIXME: maybe this is bad
		// NOTE: SourceVoices obtained this way will be returned to the voice pool when stopped!
		public static SourceVoice ObtainSourceVoice(AudioDevice device, Format format)
		{
			return device.ObtainSourceVoice(format);
		}

		// intended for short-lived sound effects
		public static SourceVoice PlayStaticSound(AudioDevice device, StaticSound sound, SubmixVoice sendVoice = null)
		{
			var voice = ObtainSourceVoice(device, sound.Format);

			if (sendVoice == null)
			{
				voice.SetOutputVoice(device.MasteringVoice);
			}
			else
			{
				voice.SetOutputVoice(sendVoice);
			}

			voice.SubmitBuffer(sound.Handle);
			voice.Play();

			return voice;
		}

		protected override unsafe void Destroy()
		{
			Stop();
			base.Destroy();
		}
	}
}