652 lines
24 KiB
C#
652 lines
24 KiB
C#
#region --- License ---
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/* Licensed under the MIT/X11 license.
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* Copyright (c) 2006-2008 the OpenTK Team.
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* This notice may not be removed from any source distribution.
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* See license.txt for licensing details.
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*/
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#endregion
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using System;
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using System.Collections.Generic;
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using System.Text;
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using System.Diagnostics;
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using OpenTK.Audio;
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namespace OpenTK.Audio
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{
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/// <summary>
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/// Provides methods to create and use an audio context.
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/// </summary>
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public sealed class AudioContext : IDisposable
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{
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#region --- Fields ---
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bool disposed;
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bool is_processing, is_synchronized;
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IntPtr device_handle;
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ContextHandle context_handle;
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bool context_exists;
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string device_name;
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static object audio_context_lock = new object();
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static List<string> available_devices = new List<string>();
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static Dictionary<ContextHandle, AudioContext> available_contexts = new Dictionary<ContextHandle, AudioContext>();
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static bool openal_supported = true;
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static Version version;
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private enum Version
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{
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OpenAL10,
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OpenAL11
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}
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#endregion
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#region --- Constructors ---
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#region static AudioContext()
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/// <private />
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/// <static />
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/// <summary>
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/// Runs before the actual class constructor, to load available devices.
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/// </summary>
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static AudioContext()
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{
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LoadAvailableDevices();
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}
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#endregion
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#region public AudioContext()
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/// <summary>Constructs a new AudioContext, using the default audio device.</summary>
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public AudioContext()
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: this(null, 0, 0, false, true) { }
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#endregion
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#region public AudioContext(string device)
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/// <summary>Constructs a new AudioContext, using the specified audio device.</summary>
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/// <param name="device">The name of the audio device to use.</param>
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/// <remarks>
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/// Use AudioContext.AvailableDevices to obtain a list of all available audio devices.
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/// devices.
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/// </remarks>
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public AudioContext(string device) : this(device, 0, 0, false, true) { }
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#endregion
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#region public AudioContext(string device, int freq)
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/// <summary>Constructs a new AudioContext, using the specified audio device and device parameters.</summary>
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/// <param name="device">The name of the audio device to use.</param>
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/// <param name="freq">Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.</param>
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/// <remarks>
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/// Use AudioContext.AvailableDevices to obtain a list of all available audio devices.
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/// devices.
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/// </remarks>
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public AudioContext(string device, int freq) : this(device, freq, 0, false, true) { }
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#endregion
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#region public AudioContext(string device, int freq, int refresh)
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/// <summary>Constructs a new AudioContext, using the specified audio device and device parameters.</summary>
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/// <param name="device">The name of the audio device to use.</param>
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/// <param name="freq">Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.</param>
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/// <param name="refresh">Refresh intervals, in units of Hz. Pass 0 for driver default.</param>
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/// <remarks>
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/// Use AudioContext.AvailableDevices to obtain a list of all available audio devices.
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/// devices.
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/// </remarks>
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public AudioContext(string device, int freq, int refresh)
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: this(device, freq, refresh, false, true) { }
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#endregion
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#region public AudioContext(string device)
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/// <summary>Constructs a new AudioContext, using the specified audio device and device parameters.</summary>
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/// <param name="device">The name of the audio device to use.</param>
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/// <param name="freq">Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.</param>
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/// <param name="refresh">Refresh intervals, in units of Hz. Pass 0 for driver default.</param>
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/// <param name="sync">Flag, indicating a synchronous context.</param>
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/// <remarks>
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/// Use AudioContext.AvailableDevices to obtain a list of all available audio devices.
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/// devices.
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/// </remarks>
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public AudioContext(string device, int freq, int refresh, bool sync)
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: this(available_devices[0], freq, refresh, sync, true) { }
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#endregion
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#region public AudioContext(string device, int freq, int refresh, bool sync, bool enableEfx)
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/// <summary>Creates the audio context using the specified device and device parameters.</summary>
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/// <param name="device">The device descriptor obtained through AudioContext.AvailableDevices.</param>
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/// <param name="freq">Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.</param>
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/// <param name="refresh">Refresh intervals, in units of Hz. Pass 0 for driver default.</param>
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/// <param name="sync">Flag, indicating a synchronous context.</param>
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/// <param name="enableEfx">Indicates whether the EFX extension should be initialized, if present.</param>
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/// <exception cref="ArgumentNullException">Occurs when the device string is invalid.</exception>
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/// <exception cref="ArgumentOutOfRangeException">Occurs when a specified parameter is invalid.</exception>
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/// <exception cref="AudioDeviceException">
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/// Occurs when the specified device is not available, or is in use by another program.
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/// </exception>
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/// <exception cref="AudioContextException">
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/// Occurs when an audio context could not be created with the specified parameters.
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/// </exception>
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/// <exception cref="NotSupportedException">
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/// Occurs when an AudioContext already exists.</exception>
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/// <remarks>
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/// <para>For maximum compatibility, you are strongly recommended to use the default constructor.</para>
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/// <para>Multiple AudioContexts are not supported at this point.</para>
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/// <para>
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/// The number of auxilliary EFX sends depends on the audio hardware and drivers. Most Realtek devices, as well
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/// as the Creative SB Live!, support 1 auxilliary send. Creative's Audigy and X-Fi series support 4 sends.
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/// Values higher than supported will be clamped by the driver.
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/// </para>
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/// </remarks>
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public AudioContext(string device, int freq, int refresh, bool sync, bool enableEfx)
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{
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CreateContext(device, freq, refresh, sync, enableEfx);
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}
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#endregion
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#endregion
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#region --- Private Methods ---
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#region static void LoadAvailableDevices()
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/// <private />
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/// <static />
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/// <summary>
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/// Loads all available audio devices into the available_devices array.
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/// </summary>
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/// <remarks>
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/// Only called by the static AudioContext constructor.
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/// </remarks>
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static void LoadAvailableDevices()
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{
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lock (audio_context_lock)
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{
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if (available_devices.Count == 0)
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{
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try
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{
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Debug.WriteLine("Enumerating audio devices.");
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Debug.Indent();
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if (Alc.IsExtensionPresent(IntPtr.Zero, "ALC_ENUMERATION_EXT"))
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{
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version = Version.OpenAL11;
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available_devices.AddRange(Alc.GetString(IntPtr.Zero, AlcGetStringList.DeviceSpecifier));
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}
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else
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{
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version = Version.OpenAL10;
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Debug.Print("Device enumeration extension not available. Failed to enumerate devices.");
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}
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foreach (string s in available_devices)
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Debug.WriteLine(s);
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}
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catch (DllNotFoundException e)
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{
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Debug.WriteLine(e.ToString());
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openal_supported = false;
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}
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finally
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{
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Debug.Unindent();
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}
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}
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}
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}
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#endregion
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#region CreateContext
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/// <private />
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/// <summary>Creates the audio context using the specified device.</summary>
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/// <param name="device">The device descriptor obtained through AudioContext.AvailableDevices, or null for the default device.</param>
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/// <param name="freq">Frequency for mixing output buffer, in units of Hz. Pass 0 for driver default.</param>
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/// <param name="refresh">Refresh intervals, in units of Hz. Pass 0 for driver default.</param>
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/// <param name="sync">Flag, indicating a synchronous context.</param>
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/// <param name="enableEfx">Indicates whether the EFX extension should be initialized, if present.</param>
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/// /// <exception cref="ArgumentOutOfRangeException">Occurs when a specified parameter is invalid.</exception>
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/// <exception cref="AudioDeviceException">
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/// Occurs when the specified device is not available, or is in use by another program.
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/// </exception>
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/// <exception cref="AudioContextException">
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/// Occurs when an audio context could not be created with the specified parameters.
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/// </exception>
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/// <exception cref="NotSupportedException">
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/// Occurs when an AudioContext already exists.</exception>
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/// <remarks>
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/// <para>For maximum compatibility, you are strongly recommended to use the default constructor.</para>
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/// <para>Multiple AudioContexts are not supported at this point.</para>
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/// <para>
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/// The number of auxilliary EFX sends depends on the audio hardware and drivers. Most Realtek devices, as well
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/// as the Creative SB Live!, support 1 auxilliary send. Creative's Audigy and X-Fi series support 4 sends.
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/// Values higher than supported will be clamped by the driver.
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/// </para>
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/// </remarks>
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void CreateContext(string device, int freq, int refresh, bool sync, bool enableEfx)
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{
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if (!openal_supported)
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throw new DllNotFoundException("openal32.dll");
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if (version == Version.OpenAL11 && available_devices.Count == 0) // Version.OpenAL10 does not support device enumeration.
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throw new NotSupportedException("No audio hardware is available.");
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if (context_exists) throw new NotSupportedException("Multiple AudioContexts are not supported.");
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if (freq < 0) throw new ArgumentOutOfRangeException("freq", freq, "Should be greater than zero.");
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if (refresh < 0) throw new ArgumentOutOfRangeException("refresh", refresh, "Should be greater than zero.");
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if (!String.IsNullOrEmpty(device))
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device_handle = Alc.OpenDevice(device);
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if (device_handle == IntPtr.Zero)
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device_handle = Alc.OpenDevice(null);
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if (device_handle == IntPtr.Zero)
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Alc.OpenDevice(Alc.GetString(IntPtr.Zero, AlcGetString.DefaultDeviceSpecifier));
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if (device_handle == IntPtr.Zero && available_devices.Count > 0)
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device_handle = Alc.OpenDevice(available_devices[0]);
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if (device_handle == IntPtr.Zero)
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throw new AudioDeviceException(String.Format("Audio device '{0}' does not exist or is tied up by another application.",
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String.IsNullOrEmpty(device) ? "default" : device));
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CheckForAlcErrors();
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// Build the attribute list
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List<int> attributes = new List<int>();
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if (freq != 0)
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{
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attributes.Add((int)AlcContextAttributes.Frequency);
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attributes.Add(freq);
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}
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if (refresh != 0)
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{
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attributes.Add((int)AlcContextAttributes.Refresh);
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attributes.Add(refresh);
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}
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attributes.Add((int)AlcContextAttributes.Sync);
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attributes.Add(sync ? 1 : 0);
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if (enableEfx && Alc.IsExtensionPresent(device_handle, "ALC_EXT_EFX"))
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{
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int num_slots;
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Alc.GetInteger(device_handle, AlcGetInteger.EfxMaxAuxiliarySends, 1, out num_slots);
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attributes.Add((int)AlcContextAttributes.EfxMaxAuxiliarySends);
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attributes.Add(num_slots);
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}
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attributes.Add(0);
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context_handle = Alc.CreateContext(device_handle, attributes.ToArray());
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if (context_handle == ContextHandle.Zero)
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{
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Alc.CloseDevice(device_handle);
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throw new AudioContextException("The audio context could not be created with the specified parameters.");
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}
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CheckForAlcErrors();
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// HACK: OpenAL SI on Linux/ALSA crashes on MakeCurrent. This hack avoids calling MakeCurrent when
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// an old OpenAL version is detect - it may affect outdated OpenAL versions different than OpenAL SI,
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// but it looks like a good compromise for now.
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if (available_devices.Count > 0)
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MakeCurrent();
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CheckForAlcErrors();
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device_name = Alc.GetString(device_handle, AlcGetString.DeviceSpecifier);
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int attribute_count;
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Alc.GetInteger(device_handle, AlcGetInteger.AttributesSize, sizeof(int), out attribute_count);
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if (attribute_count > 0)
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{
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int[] device_attributes = new int[attribute_count];
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Alc.GetInteger(device_handle, AlcGetInteger.AllAttributes, device_attributes.Length * sizeof(int), out device_attributes[0]);
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foreach (int attr in device_attributes)
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{
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switch ((AlcContextAttributes)attr)
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{
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case AlcContextAttributes.Sync: IsSynchronized = true; break;
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}
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}
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}
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lock (audio_context_lock)
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{
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available_contexts.Add(this.context_handle, this);
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context_exists = true;
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}
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}
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#endregion
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#region void CheckForAlcErrors()
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void CheckForAlcErrors()
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{
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AlcError err = Alc.GetError(device_handle);
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if (err != AlcError.NoError)
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throw new AudioContextException(err.ToString());
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}
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#endregion
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#region static void MakeCurrent(AudioContext context)
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/// <private />
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/// <summary>Makes the specified AudioContext current in the calling thread.</summary>
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/// <param name="context">The OpenTK.Audio.AudioContext to make current, or null.</param>
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/// <exception cref="ObjectDisposedException">
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/// Occurs if this function is called after the AudioContext has been disposed.
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/// </exception>
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/// <exception cref="AudioContextException">
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/// Occurs when the AudioContext could not be made current.
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/// </exception>
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static void MakeCurrent(AudioContext context)
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{
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lock (audio_context_lock)
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{
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if (!Alc.MakeContextCurrent(context != null ? context.context_handle : ContextHandle.Zero))
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throw new AudioContextException(String.Format("ALC {0} error detected at {1}.",
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Alc.GetError(context != null ? (IntPtr)context.context_handle : IntPtr.Zero).ToString(),
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context != null ? context.ToString() : "null"));
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}
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}
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#endregion
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#region internal bool IsCurrent
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/// <summary>
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/// Gets or sets a System.Boolean indicating whether the AudioContext
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/// is current.
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/// </summary>
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/// <remarks>
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/// Only one AudioContext can be current in the application at any time,
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/// <b>regardless of the number of threads</b>.
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/// </remarks>
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internal bool IsCurrent
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{
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get
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{
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lock (audio_context_lock)
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{
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if (available_contexts.Count == 0)
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return false;
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else
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{
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return AudioContext.CurrentContext == this;
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}
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}
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}
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set
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{
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if (value) AudioContext.MakeCurrent(this);
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else AudioContext.MakeCurrent(null);
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}
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}
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#endregion
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#region IntPtr Device
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IntPtr Device { get { return device_handle; } }
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#endregion
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#endregion
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#region --- Public Members ---
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#region internal void MakeCurrent()
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/// <summary>Makes the AudioContext current in the calling thread.</summary>
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/// <exception cref="ObjectDisposedException">
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/// Occurs if this function is called after the AudioContext has been disposed.
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/// </exception>
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/// <exception cref="AudioContextException">
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/// Occurs when the AudioContext could not be made current.
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/// </exception>
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/// <remarks>
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/// Only one AudioContext can be current in the application at any time,
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/// <b>regardless of the number of threads</b>.
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/// </remarks>
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public void MakeCurrent()
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{
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AudioContext.MakeCurrent(this);
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}
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#endregion
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#region public bool IsProcessing
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/// <summary>
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/// Gets a System.Boolean indicating whether the AudioContext is
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/// currently processing audio events.
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/// </summary>
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/// <seealso cref="Process"/>
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/// <seealso cref="Suspend"/>
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public bool IsProcessing
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{
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get { return is_processing; }
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private set { is_processing = value; }
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}
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#endregion
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#region public bool IsProcessing
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/// <summary>
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/// Gets a System.Boolean indicating whether the AudioContext is
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/// synchronized.
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/// </summary>
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/// <seealso cref="Process"/>
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public bool IsSynchronized
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{
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get { return is_synchronized; }
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private set { is_synchronized = value; }
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}
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#endregion
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#region public void Process
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/// <summary>
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/// Processes queued audio events.
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/// </summary>
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/// <remarks>
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/// <para>
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/// If AudioContext.IsSynchronized is true, this function will resume
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/// the internal audio processing thread. If AudioContext.IsSynchronized is false,
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/// you will need to call this function multiple times per second to process
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/// audio events.
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/// </para>
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/// <para>
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/// In some implementations this function may have no effect.
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/// </para>
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/// </remarks>
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/// <exception cref="ObjectDisposedException">Occurs when this function is called after the AudioContext had been disposed.</exception>
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/// <seealso cref="Suspend"/>
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/// <seealso cref="IsProcessing"/>
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/// <seealso cref="IsSynchronized"/>
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public void Process()
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{
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if (disposed) throw new ObjectDisposedException(this.ToString());
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Alc.ProcessContext(this.context_handle);
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IsProcessing = true;
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}
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#endregion
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#region public void Suspend
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/// <summary>
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/// Suspends processing of audio events.
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/// </summary>
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/// <remarks>
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/// <para>
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/// To avoid audio artifacts when calling this function, set audio gain to zero before
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/// suspending an AudioContext.
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/// </para>
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/// <para>
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/// In some implementations, it can be faster to suspend processing before changing
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/// AudioContext state.
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/// </para>
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/// <para>
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/// In some implementations this function may have no effect.
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/// </para>
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/// </remarks>
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/// <exception cref="ObjectDisposedException">Occurs when this function is called after the AudioContext had been disposed.</exception>
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/// <seealso cref="Process"/>
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/// <seealso cref="IsProcessing"/>
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/// <seealso cref="IsSynchronized"/>
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public void Suspend()
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{
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if (disposed) throw new ObjectDisposedException(this.ToString());
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Alc.SuspendContext(this.context_handle);
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IsProcessing = false;
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}
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#endregion
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#region public bool SupportsExtension(string extension)
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/// <summary>
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/// Checks whether the specified OpenAL extension is supported.
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/// </summary>
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/// <param name="extension">The name of the extension to check (e.g. "ALC_EXT_EFX").</param>
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/// <returns>true if the extension is supported; false otherwise.</returns>
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|
public bool SupportsExtension(string extension)
|
|
{
|
|
if (disposed) throw new ObjectDisposedException(this.GetType().FullName);
|
|
return Alc.IsExtensionPresent(this.Device, extension);
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region public static AudioContext CurrentContext
|
|
|
|
/// <summary>
|
|
/// Gets the OpenTK.Audio.AudioContext which is current in the application.
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// Only one AudioContext can be current in the application at any time,
|
|
/// <b>regardless of the number of threads</b>.
|
|
/// </remarks>
|
|
public static AudioContext CurrentContext
|
|
{
|
|
get
|
|
{
|
|
lock (audio_context_lock)
|
|
{
|
|
if (available_contexts.Count == 0)
|
|
return null;
|
|
else
|
|
{
|
|
AudioContext context;
|
|
AudioContext.available_contexts.TryGetValue(
|
|
(ContextHandle)Alc.GetCurrentContext(),
|
|
out context);
|
|
return context;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region public static string[] AvailableDevices
|
|
|
|
/// <summary>
|
|
/// Gets a System.String array containing all available audio devices.
|
|
/// </summary>
|
|
/// <remarks>This property allocates memory.</remarks>
|
|
public static string[] AvailableDevices
|
|
{
|
|
get
|
|
{
|
|
if (available_devices.Count == 0)
|
|
LoadAvailableDevices();
|
|
return available_devices.ToArray();
|
|
}
|
|
}
|
|
|
|
#endregion
|
|
|
|
#endregion
|
|
|
|
#region --- IDisposable Members ---
|
|
|
|
/// <summary>
|
|
/// Disposes of the AudioContext, cleaning up all resources consumed by it.
|
|
/// </summary>
|
|
public void Dispose()
|
|
{
|
|
this.Dispose(true);
|
|
GC.SuppressFinalize(this);
|
|
}
|
|
|
|
void Dispose(bool manual)
|
|
{
|
|
if (!disposed)
|
|
{
|
|
if (this.IsCurrent)
|
|
this.IsCurrent = false;
|
|
|
|
if (context_handle != ContextHandle.Zero)
|
|
{
|
|
available_contexts.Remove(context_handle);
|
|
Alc.DestroyContext(context_handle);
|
|
}
|
|
|
|
if (device_handle != IntPtr.Zero)
|
|
Alc.CloseDevice(device_handle);
|
|
|
|
if (manual)
|
|
{
|
|
}
|
|
disposed = true;
|
|
}
|
|
}
|
|
|
|
~AudioContext()
|
|
{
|
|
this.Dispose(false);
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region --- Overrides ---
|
|
|
|
public override int GetHashCode()
|
|
{
|
|
return base.GetHashCode();
|
|
}
|
|
|
|
public override bool Equals(object obj)
|
|
{
|
|
return base.Equals(obj);
|
|
}
|
|
|
|
public override string ToString()
|
|
{
|
|
return String.Format("{0} (handle: {1}, device: {2})",
|
|
this.device_name, this.context_handle, this.device_handle);
|
|
}
|
|
|
|
#endregion
|
|
}
|
|
}
|