BSNESv115+: Replace the 'snes_audio_sample' callback with a dynamic audio sample vector to reduce callbacks (#3010)

* BSNESv115+: Replace the 'snes_audio_sample' callback with a dynamic audio sample vector to reduce callbacks

* fix integration for subbsnes core

* reduce buffer allocations
- also make frame setter private now that it's possible

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesApi.cs

@@ -24,6 +24,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 		[BizImport(CallingConvention.Cdecl)]
 		public abstract void snes_set_hooks_enabled(bool readHookEnabled, bool writeHookEnabled, bool executeHookEnabled);
 
+		[BizImport(CallingConvention.Cdecl)]
+		public abstract short* snes_get_audiobuffer_and_size(out int size);
 		[BizImport(CallingConvention.Cdecl)]
 		public abstract BsnesApi.SNES_REGION snes_get_region();
 		[BizImport(CallingConvention.Cdecl)]
@@ -167,7 +169,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 		}
 
 		public delegate void snes_video_frame_t(ushort* data, int width, int height, int pitch);
-		public delegate void snes_audio_sample_t(short left, short right);
 		public delegate short snes_input_poll_t(int port, int index, int id);
 		public delegate void snes_controller_latch_t();
 		public delegate void snes_no_lag_t(bool sgb_poll);
@@ -218,7 +219,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 		public sealed class SnesCallbacks
 		{
 			public snes_video_frame_t videoFrameCb;
-			public snes_audio_sample_t audioSampleCb;
 			public snes_input_poll_t inputPollCb;
 			public snes_controller_latch_t controllerLatchCb;
 			public snes_no_lag_t noLagCb;

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.IEmulator.cs

@@ -1,4 +1,7 @@
-using BizHawk.Emulation.Common;
+using System;
+using System.Runtime.InteropServices;
+using BizHawk.Common;
+using BizHawk.Emulation.Common;
 
 namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 {
@@ -8,12 +11,12 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 
 		public ControllerDefinition ControllerDefinition => _controllers.Definition;
 
+		private short[] _audioBuffer = Array.Empty<short>();
+
 		public bool FrameAdvance(IController controller, bool render, bool renderSound)
 		{
 			FrameAdvancePre(controller, render, renderSound);
 
-			IsLagFrame = true;
-
 			bool resetSignal = controller.IsPressed("Reset");
 			if (resetSignal)
 			{
@@ -26,14 +29,10 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 				Api.core.snes_power();
 			}
 
+			IsLagFrame = true;
 			// run the core for one frame
 			Api.core.snes_run(false);
-			Frame++;
-
-			if (IsLagFrame)
-			{
-				LagCount++;
-			}
+			FrameAdvancePost();
 
 			return true;
 		}
@@ -65,7 +64,32 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 			Api.core.snes_set_audio_enabled(renderSound);
 		}
 
-		public int Frame { get; set; }
+		internal void FrameAdvancePost()
+		{
+			int numSamples = UpdateAudioBuffer();
+			_soundProvider.PutSamples(_audioBuffer, numSamples / 2);
+			Frame++;
+
+			if (IsLagFrame)
+			{
+				LagCount++;
+			}
+		}
+
+		private unsafe int UpdateAudioBuffer()
+		{
+			using (Api.exe.EnterExit())
+			{
+				short* rawAudioBuffer = Api.core.snes_get_audiobuffer_and_size(out int size);
+				if (size > _audioBuffer.Length)
+					_audioBuffer = new short[size];
+				Marshal.Copy((IntPtr) rawAudioBuffer, _audioBuffer, 0, size);
+
+				return size;
+			}
+		}
+
+		public int Frame { get; private set; }
 
 		public string SystemId => VSystemID.Raw.SNES;
 
@@ -86,7 +110,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 			}
 
 			Api.Dispose();
-			_resampler.Dispose();
 			_currentMsuTrack?.Dispose();
 
 			_disposed = true;

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/BsnesCore.cs

@@ -2,6 +2,7 @@ using System;
 using System.IO;
 using BizHawk.Common;
 using BizHawk.Emulation.Common;
+using BizHawk.Emulation.Common.Base_Implementations;
 using BizHawk.Emulation.Cores.Components.W65816;
 
 // http://wiki.superfamicom.org/snes/show/Backgrounds
@@ -47,7 +48,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 				noLagCb = snes_no_lag,
 				controllerLatchCb = snes_controller_latch,
 				videoFrameCb = snes_video_refresh,
-				audioSampleCb = snes_audio_sample,
 				pathRequestCb = snes_path_request,
 				traceCb = snes_trace,
 				readHookCb = ReadHook,
@@ -80,7 +80,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 
 			// start up audio resampler
 			InitAudio();
-			ser.Register<ISoundProvider>(_resampler);
+			ser.Register<ISoundProvider>(_soundProvider);
 
 			if (IsSGB)
 			{
@@ -124,7 +124,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 		private readonly ITraceable _tracer;
 
 		private IController _controller;
-		private SpeexResampler _resampler;
+		private SimpleSyncSoundProvider _soundProvider;
 		private readonly string _romPath;
 		private bool _disposed;
 
@@ -284,12 +284,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 
 		private void InitAudio()
 		{
-			_resampler = new SpeexResampler(SpeexResampler.Quality.QUALITY_DESKTOP, 64080, 88200, 32040, 44100);
-		}
-
-		private void snes_audio_sample(short left, short right)
-		{
-			_resampler.EnqueueSample(left, right);
+			_soundProvider = new SimpleSyncSoundProvider();
 		}
 
 		private void snes_trace(string disassembly, string registerInfo)

src/BizHawk.Emulation.Cores/Consoles/Nintendo/BSNES/SubBsnesCore.cs

@@ -80,12 +80,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.BSNES
 				framePassed = _bsnesCore.Api.core.snes_run(subFrameRequested);
 			}
 
-			_bsnesCore.Frame++;
-
-			if (framePassed && _bsnesCore.IsLagFrame)
-				_bsnesCore.LagCount++;
-			else
-				_bsnesCore.IsLagFrame = false;
+			if (!framePassed) _bsnesCore.IsLagFrame = false;
+			_bsnesCore.FrameAdvancePost();
 
 			return true;
 		}

waterbox/bsnescore/bsnes/sfc/coprocessor/icd/interface.cpp

@@ -21,7 +21,7 @@ auto ICD::ppuWrite(uint2 color) -> void {
 
 auto ICD::apuWrite(float left, float right) -> void {
   double samples[] = {left, right};
-  if(!system.runAhead && system.renderAudio) stream->write(samples);
+  if(!system.runAhead && system.renderAudio && !scheduler.StepOnce) stream->write(samples);
 }
 
 auto ICD::joypWrite(bool p14, bool p15) -> void {

waterbox/bsnescore/bsnes/sfc/coprocessor/msu1/msu1.cpp

@@ -42,7 +42,7 @@ auto MSU1::main() -> void {
     }
   }
 
-  if(!system.runAhead && system.renderAudio) stream->sample(float(left), float(right));
+  if(!system.runAhead && system.renderAudio && !scheduler.StepOnce) stream->sample(float(left), float(right));
   step(1);
   synchronizeCPU();
 }

waterbox/bsnescore/bsnes/sfc/dsp/dsp.cpp

@@ -18,7 +18,7 @@ auto DSP::main() -> void {
 
   int count = spc_dsp.sample_count();
   if(count > 0) {
-    if(!system.runAhead && system.renderAudio)
+    if(!system.runAhead && system.renderAudio && !scheduler.StepOnce)
     for(uint n = 0; n < count; n += 2) {
       float left  = samplebuffer[n + 0] / 32768.0f;
       float right = samplebuffer[n + 1] / 32768.0f;

waterbox/bsnescore/bsnes/target-bsnescore/bsnescore.cpp

@@ -146,8 +146,7 @@ EXPORT void snes_init(SnesInitData* init_data)
     emulator->configure("Hacks/Coprocessor/DelayedSync", init_data->fast_coprocessors);
 
     emulator->configure("Video/BlurEmulation", false); // blurs the video when not using fast ppu. I don't like it so I disable it here :)
-    // needed in order to get audio sync working. should probably figure out what exactly this does or how to change that properly
-    Emulator::audio.setFrequency(SAMPLE_RATE);
+    Emulator::audio.setFrequency(44100); // default is 48000, but bizhawk expects 44100
 
     program->regionOverride = init_data->region_override;
 }
@@ -172,6 +171,7 @@ EXPORT void snes_reset(void)
 EXPORT bool snes_run(bool breakOnLatch)
 {
     program->breakOnLatch = breakOnLatch;
+    audioBuffer.clear();
     emulator->run();
     return scheduler.event == Scheduler::Event::Frame;
 }
@@ -294,6 +294,11 @@ EXPORT System::Region snes_get_region(void) {
     return SuperFamicom::system.region();
 }
 
+EXPORT short* snes_get_audiobuffer_and_size(int& out_size) {
+    out_size = audioBuffer.size();
+    return audioBuffer.data();
+}
+
 EXPORT char snes_get_mapper(void) {
     string board = program->superFamicom.document["game/board"].text();
     string mapper = board.split('-', 1)[0];

waterbox/bsnescore/bsnes/target-bsnescore/bsnescore.hpp

@@ -6,8 +6,6 @@
 
 #define EXPORT ECL_EXPORT
 
-#define SAMPLE_RATE 32040
-
 enum SNES_MEMORY {
     CARTRIDGE_RAM,
     CARTRIDGE_ROM,

waterbox/bsnescore/bsnes/target-bsnescore/callbacks.h

@@ -4,7 +4,6 @@
 #include <stdint.h>
 
 typedef void (*snes_video_frame_t)(const uint16_t* data, int width, int height, int pitch);
-typedef void (*snes_audio_sample_t)(int16_t left, int16_t right);
 typedef int16_t (*snes_input_poll_t)(int port, int index, int id);
 typedef void (*snes_controller_latch_t)(void);
 typedef void (*snes_no_lag_t)(bool sgb_poll);
@@ -20,7 +19,6 @@ typedef bool (*snes_msu_end_t)(void);
 
 struct SnesCallbacks {
     snes_video_frame_t snes_video_frame;
-    snes_audio_sample_t snes_audio_sample;
     snes_input_poll_t snes_input_poll;
     snes_controller_latch_t snes_controller_latch;
     snes_no_lag_t snes_no_lag;

waterbox/bsnescore/bsnes/target-bsnescore/program.cpp

@@ -8,8 +8,10 @@
 
 #include "resources.hpp"
 #include <nall/vfs/biz_file.hpp>
+#include <vector>
 
 static Emulator::Interface *emulator;
+static std::vector<short> audioBuffer;
 
 struct Program : Emulator::Platform
 {
@@ -453,9 +455,8 @@ static int16_t d2i16(double v)
 
 auto Program::audioFrame(const double* samples, uint channels) -> void
 {
-	int16_t left = d2i16(samples[0]);
-	int16_t right = d2i16(samples[1]);
-	return snesCallbacks.snes_audio_sample(left, right);
+	audioBuffer.push_back(d2i16(samples[0]));
+	audioBuffer.push_back(d2i16(samples[1]));
 }
 
 auto Program::notify(string message) -> void