Refactor OPL3 FM sound generation to process samples in smaller batches

Author: codengine

src/Spice86.Core/Emulator/Devices/Sound/Opl3Fm.cs

@@ -13,6 +13,12 @@
 ///     Virtual device which emulates OPL3 FM sound.
 /// </summary>
 public class Opl3Fm : DefaultIOPortHandler, IDisposable {
+    /// <summary>
+    ///     Maximum number of interleaved samples generated per lock acquisition when producing audio.
+    ///     Keep this value even so we always generate whole stereo frames.
+    /// </summary>
+    private const int MaxSamplesPerGenerationBatch = 256;
+
     private readonly AdLibGoldDevice? _adLibGold;
     private readonly AdLibGoldIo? _adLibGoldIo;
     private readonly Opl3Chip _chip = new();
@@ -290,9 +296,17 @@ private void RenderTo(Span<float> destination) {
 
         Span<short> interleaved = _tmpInterleaved.AsSpan(0, samples);
 
-        lock (_chipLock) {
-            interleaved.Clear();
-            _chip.GenerateStream(interleaved);
+        int processed = 0;
+        while (processed < samples) {
+            int chunkSamples = Math.Min(MaxSamplesPerGenerationBatch, samples - processed);
+            Span<short> chunk = interleaved.Slice(processed, chunkSamples);
+
+            lock (_chipLock) {
+                chunk.Clear();
+                _chip.GenerateStream(chunk);
+            }
+
+            processed += chunkSamples;
         }
 
         const float scale = 1.0f / 32768f;