SDL: Add Audio Device Change Event

TuneLab/Audio/SDL2/SDLAudioEngine.cs

@@ -13,12 +13,20 @@ internal class SDLAudioEngine : IAudioEngine
     public event Action? PlayStateChanged;
     public event Action? ProgressChanged;
 
+    public event Action? DeviceChanged;
+
+    public event Action? DevicesUpdated;
+
     public bool IsPlaying => _d.state == SDLPlaybackData.PlaybackState.Playing;
 
     public int SamplingRate => 44100;
 
     public double CurrentTime => (double)_lastPosition / SamplingRate;
 
+    public int CurrentDeviceIndex => _deviceIndex;
+
+    public string CurrentDriver => _d.driver;
+
     public void Init(IAudioProcessor processor)
     {
         var context = SynchronizationContext.Current;
@@ -38,22 +46,22 @@ public void Init(IAudioProcessor processor)
             _d = new SDLPlaybackData();
 
             // 转发事件：设备更改
-            _d.devChanged = (newVal, oldVal) =>
+            _d.devChanged = (newVal, oldVal) => { context.Post(_ => { DeviceChanged?.Invoke(); }, null); };
+            // 转发事件：播放状态更改
+            _d.stateChanged = (newVal, oldVal) =>
             {
                 context.Post(_ =>
                 {
-                    // ...
+                    PlayStateChanged?.Invoke(); //
                 }, null);
-                // Console.WriteLine($"SDLPLayback: Audio device change to {newVal}.");
             };
-            // 转发事件：播放状态更改
-            _d.stateChanged = (newVal, oldVal) =>
+            // 转发事件：设备列表更新
+            _d.devicesUpdated = () =>
             {
                 context.Post(_ =>
                 {
-                    PlayStateChanged?.Invoke(); //
+                    DevicesUpdated?.Invoke(); //
                 }, null);
-                // Console.WriteLine($"SDLPLayback: Play state change to {newVal}.");
             };
             // 转发事件：当前缓冲区被播放
             _d.samplesConsumed = val =>
@@ -107,7 +115,7 @@ public void Play()
             return;
         }
 
-        // 如果没有打开音频设备那么打开第一个音频设备
+        // 如果没有打开音频设备那么打开默认音频设备
         if (_d.curDevId == 0)
         {
             SwitchDevice(-1);
@@ -150,32 +158,33 @@ public void SwitchDevice(int deviceNumber)
     {
         if (_d.state == SDLPlaybackData.PlaybackState.Playing)
         {
-            Console.WriteLine("SDLPlayback: Don't change audio device when playing.");
+            Console.WriteLine("SDL: Don't change audio device when playing.");
             return;
         }
 
         // 打开音频设备
         uint id;
         string? deviceToOpen = deviceNumber < 0 ? null : SDL.SDL_GetAudioDeviceName(deviceNumber, 0);
+        if (deviceToOpen == null)
+        {
+            Console.WriteLine($"SDL: Open default device");
+        }
+        else
+        {
+            Console.WriteLine($"SDL: Open \"{deviceToOpen}\"");
+        }
+
         if ((id = SDL.SDL_OpenAudioDevice(
                 deviceToOpen,
                 0,
                 ref _d.spec,
                 out _,
                 0)) == 0)
         {
-            throw new IOException($"SDLPlayback: Failed to open audio device: {SDL.SDL_GetError()}.");
-        }
-
-        if (deviceToOpen == null)
-        {
-            Console.WriteLine($"SDLPlayback: Current Device");
-        }
-        else
-        {
-            Console.WriteLine($"SDLPlayback: {deviceToOpen}");
+            throw new IOException($"SDL: Failed to open audio device: {SDL.SDL_GetError()}.");
         }
 
+        _deviceIndex = deviceNumber;
         _d.setDevId(id);
     }
 
@@ -211,6 +220,7 @@ public void SwitchDriver(string driver)
 
     // SDL 相关
     private SDLPlaybackData _d;
+    private int _deviceIndex = 0;
 
     private class SampleProvider(SDLAudioEngine engine) : ISampleProvider
     {

TuneLab/Audio/SDL2/SDLGlobal.cs

@@ -23,6 +23,8 @@ public enum UserEvent
 
     public delegate void ValueEvent<T>(T val);
 
+    public delegate void VoidEvent();
+
     public static void FloatsToBytes(float[] floats, byte[] bytes, int size)
     {
         for (int i = 0; i < size; i++)

TuneLab/Audio/SDL2/SDLPlaybackData.cs

@@ -22,8 +22,10 @@ public enum PlaybackState
 
     public SDLGlobal.ValueEvent<int>? samplesConsumed;
 
+    public SDLGlobal.VoidEvent? devicesUpdated;
+
     // 播放信息
-    public string driver = "";
+    public string driver = string.Empty;
 
     public PlaybackState state = PlaybackState.Stopped;
 
@@ -103,7 +105,6 @@ public void setDevId(uint newId)
     {
         var orgId = curDevId;
         curDevId = newId;
-
         if (orgId > 0)
         {
             SDL.SDL_CloseAudioDevice(orgId);
@@ -254,6 +255,14 @@ public void poll()
                         break;
                     }
 
+                    case (int)SDL.SDL_EventType.SDL_AUDIODEVICEADDED:
+                    {
+                        // 重新检测音频设备
+                        _ = SDL.SDL_GetNumAudioDevices(0);
+                        devicesUpdated?.Invoke();
+                        break;
+                    }
+
                     // 音频设备移除
                     case (int)SDL.SDL_EventType.SDL_AUDIODEVICEREMOVED:
                     {
@@ -264,10 +273,11 @@ public void poll()
                             over = true;
                         }
 
+                        // 重新检测音频设备
+                        _ = SDL.SDL_GetNumAudioDevices(0);
+                        devicesUpdated?.Invoke();
                         break;
                     }
-                    default:
-                        break;
                 }
             }