Fix .net related problems with alphaSkia, fix player related problems

src.csharp/AlphaTab.Windows/NAudioSynthOutput.cs

@@ -14,7 +14,7 @@ public class NAudioSynthOutput : WaveProvider32, ISynthOutput, IDisposable
     {
         private const int BufferSize = 4096;
         private const int PreferredSampleRate = 44100;
-        
+
         private DirectSoundOut _context;
         private CircularSampleBuffer _circularBuffer;
         private int _bufferCount = 0;
@@ -27,7 +27,7 @@ public class NAudioSynthOutput : WaveProvider32, ISynthOutput, IDisposable
         /// Initializes a new instance of the <see cref="NAudioSynthOutput"/> class.
         /// </summary>
         public NAudioSynthOutput()
-            : base(PreferredSampleRate, 2)
+            : base(PreferredSampleRate, (int)SynthConstants.AudioChannels)
         {
             _context = null!;
             _circularBuffer = null!;
@@ -42,16 +42,21 @@ public void Activate()
         /// <inheritdoc />
         public void Open(double bufferTimeInMilliseconds)
         {
+            var latency = 40;
+            _context = new DirectSoundOut(latency);
+            _context.Init(this);
+
+            // NAudio introduces another level of buffering and latency
+            // we've seen that this can cause our buffers to deplete
+            // as a mitigation we buffer a lot more
             _bufferCount = (int)(
                 (bufferTimeInMilliseconds * PreferredSampleRate) /
                 1000 /
                 BufferSize
-            );
+            ) * 4;
             _circularBuffer = new CircularSampleBuffer(BufferSize * _bufferCount);
-            _context = new DirectSoundOut(100);
-            _context.Init(this);
 
-            ((EventEmitter) Ready).Trigger();
+            ((EventEmitter)Ready).Trigger();
         }
 
         /// <inheritdoc />
@@ -112,12 +117,12 @@ private void RequestBuffers()
             // before we already get samples via addSamples, therefore we need to
             // remember how many buffers have been requested, and consider them as available.
             var bufferedSamples = _circularBuffer.Count + _requestedBufferCount * BufferSize;
- 
+
             if (bufferedSamples < halfSamples)
             {
                 for (var i = 0; i < halfBufferCount; i++)
                 {
-                    ((EventEmitter) SampleRequest).Trigger();
+                    ((EventEmitter)SampleRequest).Trigger();
                     _requestedBufferCount++;
                 }
             }
@@ -127,17 +132,19 @@ private void RequestBuffers()
         public override int Read(float[] buffer, int offset, int count)
         {
             var read = new Float32Array(count);
-
-            var samplesFromBuffer = _circularBuffer.Read(read, 0, System.Math.Min(read.Length, _circularBuffer.Count));
+
+            var samplesFromBuffer = (int)_circularBuffer.Read(read, 0,
+                System.Math.Min(read.Length, _circularBuffer.Count));
 
             Buffer.BlockCopy(read.Data, 0, buffer, offset * sizeof(float),
-                count * sizeof(float));
+                samplesFromBuffer * sizeof(float));
 
-            var samples = count / 2;
-            ((EventEmitterOfT<double>) SamplesPlayed).Trigger(samples / SynthConstants.AudioChannels);
+            ((EventEmitterOfT<double>)SamplesPlayed).Trigger(samplesFromBuffer /
+                                                             SynthConstants.AudioChannels);
 
             RequestBuffers();
 
+
             return count;
         }
 

src.csharp/AlphaTab.Windows/WinForms/SkiaUtil.cs → src.csharp/AlphaTab.Windows/WinForms/AlphaSkiaUtil.cs

@@ -1,13 +1,14 @@
 using System.Drawing;
 using System.Drawing.Imaging;
-using AlphaSkia;
+using AlphaTab.Platform.Skia.AlphaSkiaBridge;
 
 namespace AlphaTab.WinForms
 {
-    internal static class SkiaUtil
+    internal static class AlphaSkiaUtil
     {
-        public static Bitmap ToBitmap(AlphaSkiaImage image)
+        public static Bitmap ToBitmap(AlphaSkiaImage imageBridge)
         {
+            var image = imageBridge.Image;
             var bitmap = new Bitmap(image.Width, image.Height, PixelFormat.Format32bppPArgb);
             var bitmapData =
                 bitmap.LockBits(new Rectangle(Point.Empty, bitmap.Size), ImageLockMode.WriteOnly,

src.csharp/AlphaTab.Windows/WinForms/WinFormsUiFacade.cs

@@ -3,10 +3,10 @@
 using System.Drawing;
 using System.IO;
 using System.Windows.Forms;
-using AlphaSkia;
 using AlphaTab.Synth;
 using AlphaTab.Platform;
 using AlphaTab.Platform.CSharp;
+using AlphaTab.Platform.Skia.AlphaSkiaBridge;
 using AlphaTab.Rendering;
 using AlphaTab.Rendering.Utils;
 
@@ -146,7 +146,7 @@ public override void BeginUpdateRenderResults(RenderFinishedEventArgs? r)
                     case AlphaSkiaImage skiaImage:
                         using (skiaImage)
                         {
-                            source = SkiaUtil.ToBitmap(skiaImage);
+                            source = AlphaSkiaUtil.ToBitmap(skiaImage);
                         }
 
                         break;

src.csharp/AlphaTab.Windows/Wpf/SkImageSource.cs → src.csharp/AlphaTab.Windows/Wpf/AlphaSkiaImageSource.cs

@@ -1,14 +1,15 @@
 using System.Windows;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
-using AlphaSkia;
+using AlphaTab.Platform.Skia.AlphaSkiaBridge;
 
 namespace AlphaTab.Wpf
 {
-    internal static class SkImageSource
+    internal static class AlphaSkiaImageSource
     {
-        public static BitmapSource Create(AlphaSkiaImage image)
+        public static BitmapSource Create(AlphaSkiaImage imageBridge)
         {
+            var image = imageBridge.Image;
             var bitmap = new WriteableBitmap(image.Width, image.Height, 96, 96, PixelFormats.Pbgra32, null);
             bitmap.Lock();
             // copy

src.csharp/AlphaTab.Windows/Wpf/WpfUiFacade.cs

@@ -7,10 +7,10 @@
 using System.Windows.Data;
 using System.Windows.Media;
 using System.Windows.Shapes;
-using AlphaSkia;
 using AlphaTab.Synth;
 using AlphaTab.Platform;
 using AlphaTab.Platform.CSharp;
+using AlphaTab.Platform.Skia.AlphaSkiaBridge;
 using AlphaTab.Rendering;
 using AlphaTab.Rendering.Utils;
 using Point = System.Windows.Point;
@@ -158,7 +158,7 @@ public override void BeginUpdateRenderResults(RenderFinishedEventArgs? r)
                     {
                         using (skiaImage)
                         {
-                            source = SkImageSource.Create(skiaImage);
+                            source = AlphaSkiaImageSource.Create(skiaImage);
                         }
                     }
                     else if (body is System.Drawing.Bitmap image)

src.csharp/AlphaTab/Platform/Skia/AlphaSkiaBridge/AlphaSkiaBridge.cs

@@ -18,11 +18,17 @@ internal enum AlphaSkiaTextBaseline
     Bottom = AlphaSkia.AlphaSkiaTextBaseline.Bottom
 }
 
-internal class AlphaSkiaImage : IDisposable
+/// <summary>
+/// Bridge between alphaTab and <see cref="AlphaSkia.AlphaSkiaImage"/>
+/// </summary>
+public class AlphaSkiaImage : IDisposable
 {
-    internal AlphaSkia.AlphaSkiaImage Image { get; }
-    public double Width => Image.Width;
-    public double Height => Image.Height;
+    /// <summary>
+    /// Gets the target <see cref="AlphaSkia.AlphaSkiaImage"/>.
+    /// </summary>
+    public AlphaSkia.AlphaSkiaImage Image { get; }
+    internal double Width => Image.Width;
+    internal double Height => Image.Height;
 
     internal AlphaSkiaImage(AlphaSkia.AlphaSkiaImage image)
     {
@@ -34,7 +40,7 @@ public void Dispose()
         Image.Dispose();
     }
 
-    public ArrayBuffer? ReadPixels()
+    internal ArrayBuffer? ReadPixels()
     {
         var data = Image.ReadPixels();
         if (data == null)
@@ -45,7 +51,7 @@ public void Dispose()
         return new ArrayBuffer(new ArraySegment<byte>(data, 0, data.Length));
     }
 
-    public ArrayBuffer? ToPng()
+    internal ArrayBuffer? ToPng()
     {
         var data = Image.ToPng();
         if (data == null)
@@ -56,20 +62,23 @@ public void Dispose()
         return new ArrayBuffer(new ArraySegment<byte>(data, 0, data.Length));
     }
 
-    public static AlphaSkiaImage? Decode(ArrayBuffer buffer)
+    internal static AlphaSkiaImage? Decode(ArrayBuffer buffer)
     {
         var underlying = AlphaSkia.AlphaSkiaImage.Decode(buffer.Raw.Array!);
         return underlying == null ? null : new AlphaSkiaImage(underlying);
     }
 
-    public static AlphaSkiaImage? FromPixels(double width, double height, ArrayBuffer pixels)
+    internal static AlphaSkiaImage? FromPixels(double width, double height, ArrayBuffer pixels)
     {
         var underlying =
             AlphaSkia.AlphaSkiaImage.FromPixels((int)width, (int)height, pixels.Raw.Array!);
         return underlying == null ? null : new AlphaSkiaImage(underlying);
     }
 }
 
+/// <summary>
+/// Bridge between alphaTab and <see cref="AlphaSkia.AlphaSkiaCanvas"/>
+/// </summary>
 internal class AlphaSkiaCanvas : IDisposable
 {
     private readonly AlphaSkia.AlphaSkiaCanvas _canvas = new();
@@ -177,10 +186,10 @@ public void Stroke()
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public void FillText(string text, AlphaSkiaTypeface typeface, double fontSize, double x,
         double y,
-        AlphaSkiaTextAlign textAlign, AlphaSkiaTextBaseline baseline)
+        AlphaSkiaTextAlign textAlign, AlphaSkiaTextBaseline baselineBridge)
     {
         _canvas.FillText(text, typeface.Typeface, (float)fontSize, (float)x, (float)y,
-            (AlphaSkia.AlphaSkiaTextAlign)textAlign, (AlphaSkia.AlphaSkiaTextBaseline)baseline);
+            (AlphaSkia.AlphaSkiaTextAlign)textAlign, (AlphaSkia.AlphaSkiaTextBaseline)baselineBridge);
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]