Merge pull request #26 from SineStriker/master

Add SDL2 Playback Engine

TuneLab/App.axaml.cs

@@ -11,6 +11,7 @@
 using TuneLab.GUI;
 using TuneLab.Extensions.Voices;
 using TuneLab.Audio.NAudio;
+using TuneLab.Audio.SDL2;
 
 namespace TuneLab;
 
@@ -48,7 +49,7 @@ public override void OnFrameworkInitializationCompleted()
                 };
 
                 AudioUtils.Init(new NAudioCodec());
-                AudioEngine.Init(new NAudioEngine());
+                AudioEngine.Init(new SDLAudioEngine());
                 ExtensionManager.LoadExtensions();
                 desktop.MainWindow = new MainWindow();
             }

TuneLab/Audio/SDL2/SDLAudioEngine.cs

@@ -0,0 +1,213 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Threading;
+using NAudio.Wave;
+using SDL2;
+
+namespace TuneLab.Audio.SDL2;
+
+internal class SDLAudioEngine : IAudioEngine
+{
+    public event Action? PlayStateChanged;
+    public event Action? ProgressChanged;
+
+    public bool IsPlaying => _d.state == SDLPlaybackData.PlaybackState.Playing;
+
+    public int SamplingRate => 44100;
+
+    public double CurrentTime => (double)(_position) / SamplingRate;
+
+    public void Init(IAudioProcessor processor)
+    {
+        var context = SynchronizationContext.Current;
+        if (context == null)
+        {
+            throw new Exception("Can't get SynchronizationContext");
+        }
+
+        _audioProcessor = processor;
+
+        // Begin initialize SDL
+        {
+            // 初始化SDL引擎，有备无患
+            _ = SDLHost.InitHost();
+
+            // 创建私有结构
+            _d = new SDLPlaybackData();
+
+            // 转发事件
+            _d.devChanged = (newVal, oldVal) =>
+            {
+                context.Post(_ =>
+                {
+                    // ...
+                }, null);
+                Console.WriteLine($"SDLPLayback: Audio device change to {newVal}.");
+            };
+            _d.stateChanged = (newVal, oldVal) =>
+            {
+                context.Post(_ =>
+                {
+                    PlayStateChanged?.Invoke(); //
+                }, null);
+                Console.WriteLine($"SDLPLayback: Play state change to {newVal}.");
+            };
+
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                _d.setDriver("directsound");
+            }
+
+            // 创建 sample provider
+            var sampleProvider = new SampleProvider(this);
+
+            // 创建音频结构体
+            _d.spec.freq = SamplingRate;
+            _d.spec.format = SDLGlobal.PLAYBACK_FORMAT;
+            _d.spec.channels = (byte)sampleProvider.WaveFormat.Channels;
+            _d.spec.silence = 0;
+
+            _d.sampleProvider = sampleProvider;
+            _d.setDevId(0);
+
+            // 打开默认音频设备延迟到播放操作时
+        }
+        // End initialize SDL
+
+        System.Timers.Timer timer = new(16);
+        timer.Elapsed += (s, e) =>
+        {
+            context.Post(_ =>
+            {
+                if (IsPlaying)
+                {
+                    ProgressChanged?.Invoke();
+                }
+            }, null);
+        };
+        timer.Start();
+    }
+
+    public void Destroy()
+    {
+        // 先关闭音频
+        Pause();
+
+        _d.sampleProvider = null;
+        _d.setDevId(0);
+
+        _d.setDriver("");
+    }
+
+    public void Play()
+    {
+        Console.WriteLine("Play");
+        if (IsPlaying)
+        {
+            return;
+        }
+
+        // 如果没有打开音频设备那么打开第一个音频设备
+        if (_d.curDevId == 0)
+        {
+            SwitchDevice(0);
+        }
+
+        _d.start();
+    }
+
+    public void Pause()
+    {
+        if (!IsPlaying)
+        {
+            return;
+        }
+
+        _d.stop();
+    }
+
+    public void Seek(double time)
+    {
+        _position = (int)(time * SamplingRate);
+    }
+
+    public void SwitchDevice(int deviceNumber)
+    {
+        if (_d.state == SDLPlaybackData.PlaybackState.Playing)
+        {
+            Console.WriteLine("SDLPlayback: Don't change audio device when playing.");
+            return;
+        }
+
+        _d.devNum = deviceNumber;
+
+        // 打开音频设备
+        uint id;
+        if ((id = SDL.SDL_OpenAudioDevice(
+                SDL.SDL_GetAudioDeviceName(_d.devNum, 0),
+                0,
+                ref _d.spec,
+                out _,
+                0)) == 0)
+        {
+            throw new IOException($"SDLPlayback: Failed to open audio device: {SDL.SDL_GetError()}.");
+        }
+
+        Console.WriteLine($"SDLPlayback: {SDL.SDL_GetAudioDeviceName(_d.devNum, 0)}");
+
+        _d.setDevId(id);
+    }
+
+    public List<string> GetDrivers()
+    {
+        var res = new List<string>();
+        int cnt = SDL.SDL_GetNumAudioDrivers();
+        for (int i = 0; i < cnt; i++)
+        {
+            var dev = SDL.SDL_GetAudioDriver(i);
+            if (dev == "dummy" || dev == "disk")
+            {
+                continue;
+            }
+
+            res.Add(dev);
+        }
+
+        return res;
+    }
+
+    public void SwitchDriver(string driver)
+    {
+        _d.setDriver(driver);
+    }
+
+    // 成员变量
+    IAudioProcessor? _audioProcessor;
+    int _position = 0;
+
+    // SDL 相关
+    SDLPlaybackData _d;
+
+    class SampleProvider(SDLAudioEngine engine) : ISampleProvider
+    {
+        public WaveFormat WaveFormat => WaveFormat.CreateIeeeFloatWaveFormat(engine.SamplingRate, 2);
+
+        public int Read(float[] buffer, int offset, int count)
+        {
+            int position = engine._position;
+            int length = count / 2;
+
+            engine._position += length;
+
+            for (int i = offset; i < offset + count; i++)
+            {
+                buffer[i] = 0;
+            }
+
+            engine._audioProcessor?.ProcessBlock(buffer, offset, position, length);
+            return count;
+        }
+    }
+}

TuneLab/Audio/SDL2/SDLGlobal.cs

@@ -0,0 +1,40 @@
+using System;
+using SDL2;
+
+namespace TuneLab.Audio.SDL2;
+
+internal static class SDLGlobal
+{
+    // 全局配置信息
+    public static readonly ushort PLAYBACK_FORMAT = SDL.AUDIO_F32SYS; // 32位浮点
+
+    public static readonly ushort PLAYBACK_BUFFER_SAMPLES = 1024; // 默认缓冲区长度
+
+    public static readonly uint PLAYBACK_POLL_INTERVAL = 1; // 轮循时间间隔(ms)
+
+    // 用户事件
+    public enum UserEvent
+    {
+        SDL_EVENT_BUFFER_END = (int)SDL.SDL_EventType.SDL_USEREVENT + 1,
+        SDL_EVENT_MANUAL_STOP,
+    }
+
+    public delegate void ValueChangeEvent<T>(T newVal, T orgVal);
+
+    public static void FloatsToBytes(float[] floats, byte[] bytes, int size)
+    {
+        for (int i = 0; i < size; i++)
+        {
+            if (i >= floats.Length || i * 4 + 3 >= bytes.Length)
+            {
+                break;
+            }
+
+            var b = BitConverter.GetBytes(floats[i]);
+            bytes[i * 4] = b[0];
+            bytes[i * 4 + 1] = b[1];
+            bytes[i * 4 + 2] = b[2];
+            bytes[i * 4 + 3] = b[3];
+        }
+    }
+}

TuneLab/Audio/SDL2/SDLHost.cs

@@ -0,0 +1,86 @@
+using System;
+using System.ComponentModel;
+using System.Runtime.InteropServices;
+using SDL2;
+
+namespace TuneLab.Audio.SDL2;
+
+internal class SDLHost
+{
+    private static SDLHost self = null;
+
+    // 初始化
+    public static SDLHost InitHost()
+    {
+        return Instance;
+    }
+
+    // 反初始化
+    public static void QuitHost()
+    {
+        if (self == null)
+        {
+            return;
+        }
+
+        self = null;
+        GC.Collect(); // 强制删除
+    }
+
+    // 构造函数
+    public SDLHost()
+    {
+        // 初始化单例
+        if (self != null)
+        {
+            throw new Exception("SDLHost: Duplicated SDL Host.");
+        }
+
+        self = this;
+
+        // 设置输出级别
+        SDL.SDL_LogSetPriority(
+            (int)SDL.SDL_LogCategory.SDL_LOG_CATEGORY_APPLICATION,
+            SDL.SDL_LogPriority.SDL_LOG_PRIORITY_INFO
+        );
+
+        // 初始化
+        if (SDL.SDL_Init(SDL.SDL_INIT_AUDIO) < 0)
+        {
+            throw new Exception($"SDLHost: Failed to initialize SDL: {SDL.SDL_GetError()}.");
+        }
+    }
+
+    // 析构函数
+    ~SDLHost()
+    {
+        SDL.SDL_Quit();
+    }
+
+    public static SDLHost Instance => self == null ? self = new SDLHost() : self;
+
+    // 获取版本号
+    public int[] GetVersion()
+    {
+        SDL.SDL_GetVersion(out var ver);
+        return new int[] { ver.major, ver.minor, ver.patch };
+    }
+
+    // 获取输出设备数
+    public int NumOutputDevices()
+    {
+        return SDL.SDL_GetNumAudioDevices(0);
+    }
+
+    // 获取输入设备数
+    public int NumInputDevices()
+    {
+        return SDL.SDL_GetNumAudioDevices(1);
+    }
+
+    // 获取输出设备
+    public int NumAudioDrivers()
+    {
+        return SDL.SDL_GetNumAudioDrivers();
+    }
+}