Virtu/Library/DirectSound.cs
Sean Fausett 5485e01e02 Added ApplicationBase.InitializeOutOfBrowserUpdate to Silverlight library.
Fixed race condition in DirectSound wrapper; between SetVolume and Uninitialize.

--HG--
extra : convert_revision : svn%3Affd33b8c-2492-42e0-bdc5-587b920b7d6d/trunk%4050691
2010-08-22 11:04:52 +00:00

174 lines
5.4 KiB
C#

using System;
using System.Runtime.InteropServices;
using System.Security;
using System.Threading;
namespace Jellyfish.Library
{
public sealed partial class DirectSound : IDisposable
{
[SecurityCritical]
public DirectSound(int sampleRate, int sampleChannels, int sampleBits, int sampleSize, Action<IntPtr, int> updater)
{
_sampleRate = sampleRate;
_sampleChannels = sampleChannels;
_sampleBits = sampleBits;
_sampleSize = sampleSize;
_thread = new Thread(Run) { Name = "DirectSound" };
_updater = updater;
}
public void Dispose()
{
_position1Event.Close();
_position2Event.Close();
_stopEvent.Close();
}
public void SetVolume(double volume)
{
int attenuation = (volume < 0.01) ? (int)BufferVolume.Min : (int)Math.Floor(100 * 20 * Math.Log10(volume)); // 100 db
lock (_bufferLock)
{
if (_buffer != null)
{
_buffer.SetVolume(attenuation);
}
}
}
public void Start(IntPtr window)
{
_window = window;
_thread.Start();
}
public void Stop()
{
_stopEvent.Set();
_thread.Join();
}
[SecurityCritical]
private void Initialize()
{
int hresult = NativeMethods.DirectSoundCreate(IntPtr.Zero, out _device, IntPtr.Zero);
if (hresult < 0)
{
Marshal.ThrowExceptionForHR(hresult);
}
_device.SetCooperativeLevel(_window, CooperativeLevel.Normal);
GCHandleHelpers.Pin(new WaveFormat(_sampleRate, _sampleChannels, _sampleBits), waveFormat =>
{
var description = new BufferDescription(BufferCapabilities.CtrlPositionNotify | BufferCapabilities.CtrlVolume, BlockCount * _sampleSize, waveFormat);
_device.CreateSoundBuffer(description, out _buffer, IntPtr.Zero);
});
ClearBuffer();
var positionEvents = new BufferPositionNotify[BlockCount]
{
new BufferPositionNotify(0 * _sampleSize, _position1Event), new BufferPositionNotify(1 * _sampleSize, _position2Event)
};
((IDirectSoundNotify)_buffer).SetNotificationPositions(positionEvents.Length, positionEvents);
_buffer.Play(0, 0, BufferPlay.Looping);
}
[SecurityCritical]
private void ClearBuffer()
{
UpdateBuffer(0, 0, BufferLock.EntireBuffer, (buffer, bufferSize) => MarshalHelpers.ZeroMemory(buffer, bufferSize));
}
private void RestoreBuffer()
{
BufferStatus status;
_buffer.GetStatus(out status);
if ((status & BufferStatus.BufferLost) != 0)
{
_buffer.Restore();
}
}
private void UpdateBuffer(int offset, int count, BufferLock flags, Action<IntPtr, int> updater)
{
RestoreBuffer();
IntPtr buffer1, buffer2;
int buffer1Size, buffer2Size;
_buffer.Lock(offset, count, out buffer1, out buffer1Size, out buffer2, out buffer2Size, flags);
try
{
if (buffer1 != IntPtr.Zero)
{
updater(buffer1, buffer1Size);
}
if (buffer2 != IntPtr.Zero)
{
updater(buffer2, buffer2Size);
}
}
finally
{
_buffer.Unlock(buffer1, buffer1Size, buffer2, buffer2Size);
}
}
private void Uninitialize()
{
lock (_bufferLock)
{
if (_buffer != null)
{
_buffer.Stop();
Marshal.ReleaseComObject(_buffer);
_buffer = null;
}
}
if (_device != null)
{
Marshal.ReleaseComObject(_device);
_device = null;
}
}
[SecurityCritical]
private void Run() // com mta thread
{
Initialize();
var eventHandles = new EventWaitHandle[] { _position1Event, _position2Event, _stopEvent };
int index = WaitHandle.WaitAny(eventHandles);
while (index < BlockCount)
{
UpdateBuffer(((index + 1) % BlockCount) * _sampleSize, _sampleSize, BufferLock.None, _updater); // update next block in circular buffer
index = WaitHandle.WaitAny(eventHandles);
}
Uninitialize();
}
private const int BlockCount = 2;
private int _sampleRate;
private int _sampleChannels;
private int _sampleBits;
private int _sampleSize;
private Thread _thread;
private IntPtr _window;
private IDirectSound _device;
private IDirectSoundBuffer _buffer;
private object _bufferLock = new object();
private Action<IntPtr, int> _updater;
private AutoResetEvent _position1Event = new AutoResetEvent(false);
private AutoResetEvent _position2Event = new AutoResetEvent(false);
private ManualResetEvent _stopEvent = new ManualResetEvent(false);
}
}