nes: vrc6: new audio implementation. sounds awesome

BizHawk.Emulation/BizHawk.Emulation.csproj

@@ -532,6 +532,7 @@
     <Compile Include="Consoles\Sega\Genesis\IO.cs" />
     <Compile Include="Consoles\Sega\Genesis\MemoryMap.68000.cs" />
     <Compile Include="Consoles\Sega\Genesis\MemoryMap.Z80.cs" />
+    <Compile Include="Sound\VRC6Alt.cs" />
     <Compile Include="Sound\YM2612.cs" />
     <Compile Include="Consoles\Sega\SMS\BIOS.cs" />
     <Compile Include="Sound\Utilities\SoundMixer.cs" />

BizHawk.Emulation/Consoles/Nintendo/NES/Boards/VRC6.cs

@@ -12,7 +12,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 		int prg_bank_mask_8k, chr_bank_mask_1k;
 		bool newer_variant;
 
-		Sound.VRC6 VRC6Sound = new Sound.VRC6();
+		//Sound.VRC6 VRC6Sound = new Sound.VRC6();
+		Sound.VRC6Alt VRC6Sound;
 
 		//state
 		int prg_bank_16k, prg_bank_8k;
@@ -29,6 +30,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			base.Dispose();
 			prg_banks_8k.Dispose();
 			chr_banks_1k.Dispose();
+			VRC6Sound.Dispose();
 		}
 
 		public override void SyncState(Serializer ser)
@@ -93,6 +95,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			SyncPRG();
 			SetMirrorType(EMirrorType.Vertical);
 
+			VRC6Sound = new Sound.VRC6Alt((uint)NES.cpuclockrate);
+
 			return true;
 		}
 		public override byte ReadPRG(int addr)
@@ -246,6 +250,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 
 		public override void ClockCPU()
 		{
+			VRC6Sound.Clock();
+
 			if (!irq_enabled) return;
 
 			if (irq_mode)
@@ -265,6 +271,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 
 		public override void ApplyCustomAudio(short[] samples)
 		{
+			/*
 			short[] fmsamples = new short[samples.Length];
 			VRC6Sound.GetSamples(fmsamples);
 			int len = samples.Length;
@@ -272,6 +279,8 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 			{
 				samples[i] = (short)((samples[i] >> 1) + (fmsamples[i] >> 1));
 			}
+			*/
+			VRC6Sound.ApplyCustomAudio(samples);
 		}
 
 	}

BizHawk.Emulation/Sound/VRC6Alt.cs

@@ -0,0 +1,314 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace BizHawk.Emulation.Sound
+{
+	public class VRC6Alt : IDisposable
+	{
+		// http://wiki.nesdev.com/w/index.php/VRC6_audio
+		// $9003 not implemented
+
+
+
+
+
+		#region blip-buf interface
+
+		Sound.Utilities.BlipBuffer blip;
+		// yes, some of this is copy+pasted from the FDS, and more or less from the NES
+		// as soon as i decide that i like it and i use it a third time, i'll put it in a class
+
+		struct Delta
+		{
+			public uint time;
+			public int value;
+			public Delta(uint time, int value)
+			{
+				this.time = time;
+				this.value = value;
+			}
+		}
+		List<Delta> dlist = new List<Delta>();
+
+		uint sampleclock = 0;
+		const int blipsize = 4096;
+
+		short[] mixout = new short[blipsize];
+
+		public void ApplyCustomAudio(short[] samples)
+		{
+			int nsamp = samples.Length / 2;
+			if (nsamp > blipsize) // oh well.
+				nsamp = blipsize;
+			uint targetclock = (uint)blip.ClocksNeeded(nsamp);
+			foreach (var d in dlist)
+				blip.AddDelta(d.time * targetclock / sampleclock, d.value);
+			dlist.Clear();
+			blip.EndFrame(targetclock);
+			sampleclock = 0;
+			blip.ReadSamples(mixout, nsamp, false);
+
+			for (int i = 0, j = 0; i < nsamp; i++, j += 2)
+			{
+				int s = mixout[i] +samples[j];
+				if (s > 32767)
+					samples[j] = 32767;
+				else if (s <= -32768)
+					samples[j] = -32768;
+				else
+					samples[j] = (short)s;
+				// nes audio is mono, so we can ignore the original value of samples[j+1]
+				samples[j + 1] = samples[j];
+			}
+		}
+
+		#endregion
+
+		Pulse pulse1, pulse2;
+		Saw saw;
+
+		/// <summary>
+		/// 
+		/// </summary>
+		/// <param name="freq">frequency of the M2 clock in hz</param>
+		public VRC6Alt(uint freq)
+		{
+			if (freq > 0)
+			{
+				blip = new Utilities.BlipBuffer(blipsize);
+				blip.SetRates(freq, 44100);
+			}
+			pulse1 = new Pulse(PulseAddDiff);
+			pulse2 = new Pulse(PulseAddDiff);
+			saw = new Saw(SawAddDiff);
+		}
+
+		public void Dispose()
+		{
+			if (blip != null)
+			{
+				blip.Dispose();
+				blip = null;
+			}
+		}
+
+		void PulseAddDiff(int value)
+		{
+			dlist.Add(new Delta(sampleclock, value * 360));
+		}
+		void SawAddDiff(int value)
+		{
+			dlist.Add(new Delta(sampleclock, value * 180));
+		}
+
+		public void SyncState(Serializer ser)
+		{
+			ser.BeginSection("VRC6Alt");
+			pulse1.SyncState(ser);
+			pulse2.SyncState(ser);
+			saw.SyncState(ser);
+			ser.EndSection();
+		}
+
+		public void Write9000(byte value) { pulse1.Write0(value); }
+		public void Write9001(byte value) { pulse1.Write1(value); }
+		public void Write9002(byte value) { pulse1.Write2(value); }
+
+		public void Write9003(byte value)
+		{
+
+		}
+
+		public void WriteA000(byte value) { pulse2.Write0(value); }
+		public void WriteA001(byte value) { pulse2.Write1(value); }
+		public void WriteA002(byte value) { pulse2.Write2(value); }
+
+		public void WriteB000(byte value) { saw.Write0(value); }
+		public void WriteB001(byte value) { saw.Write1(value); }
+		public void WriteB002(byte value) { saw.Write2(value); }
+
+		public void Clock()
+		{
+			pulse1.Clock();
+			pulse2.Clock();
+			saw.Clock();
+			sampleclock++;
+		}
+
+		class Saw
+		{
+			Action<int> SendDiff;
+			public Saw(Action<int> SendDiff) { this.SendDiff = SendDiff; }
+
+			// set by regs
+			byte A;
+			int F;
+			bool E;
+			// internal state
+			int count;
+			byte accum;
+			int acount;
+			int value;
+
+			void SendNew()
+			{
+				int newvalue = accum >> 3;
+				if (newvalue != value)
+				{
+					SendDiff(value - newvalue); // intentionally flipped
+					value = newvalue;
+				}
+			}
+
+			public void SyncState(Serializer ser)
+			{
+				ser.Sync("A", ref A);
+				ser.Sync("F", ref F);
+				ser.Sync("E", ref E);
+				ser.Sync("count", ref count);
+				ser.Sync("accum", ref accum);
+				ser.Sync("acount", ref acount);
+				ser.Sync("value", ref value);
+			}
+
+			public void Write0(byte value)
+			{
+				A = (byte)(value & 63);
+			}
+			public void Write1(byte value)
+			{
+				F &= 0xf00;
+				F |= value;
+			}
+			public void Write2(byte value)
+			{
+				F &= 0x0ff;
+				F |= value << 8 & 0xf00;
+				E = value.Bit(7);
+				if (!E)
+				{
+					accum = 0;
+					SendNew();
+				}
+			}
+
+			public void Clock()
+			{
+				if (!E)
+					return;
+				count--;
+				if (count <= 0)
+				{
+					count = F;
+					acount++;
+					if (acount % 2 == 0)
+					{
+						if (acount < 14)
+						{
+							accum += A;
+						}
+						else
+						{
+							accum = 0;
+							acount = 0;
+						}
+						SendNew();
+					}
+				}
+			}
+		}
+
+		class Pulse
+		{
+			Action<int> SendDiff;
+			public Pulse(Action<int> SendDiff) { this.SendDiff = SendDiff; }
+
+			// set by regs
+			int V;
+			int D;
+			int F;
+			bool E;
+			// internal state
+			int count;
+			int duty;
+			int value;
+
+			void SendNew()
+			{
+				int newvalue;
+				if (duty <= D)
+					newvalue = V;
+				else
+					newvalue = 0;
+				if (newvalue != value)
+				{
+					SendDiff(value - newvalue); // intentionally flipped
+					value = newvalue;
+				}
+			}
+
+			void SendNewZero()
+			{
+				if (0 != value)
+				{
+					SendDiff(value - 0); // intentionally flipped
+					value = 0;
+				}
+			}
+
+			public void SyncState(Serializer ser)
+			{
+				ser.Sync("V", ref V);
+				ser.Sync("D", ref D);
+				ser.Sync("F", ref F);
+				ser.Sync("E", ref E);
+				ser.Sync("count", ref count);
+				ser.Sync("duty", ref duty);
+				ser.Sync("value", ref value);
+			}
+
+			public void Write0(byte value)
+			{
+				V = value & 15;
+				if (value.Bit(7))
+					D = 16;
+				else
+					D = value >> 4 & 7;
+				SendNew(); // this actually happens, right?
+			}
+			public void Write1(byte value)
+			{
+				F &= 0xf00;
+				F |= value;
+			}
+			public void Write2(byte value)
+			{
+				F &= 0x0ff;
+				F |= value << 8 & 0xf00;
+				E = value.Bit(7);
+				if (E)
+					SendNew();
+				else
+					SendNewZero();
+			}
+
+			public void Clock()
+			{
+				if (!E)
+					return;
+				count--;
+				if (count <= 0)
+				{
+					count = F;
+					duty--;
+					if (duty < 0)
+						duty += 16;
+					SendNew();
+				}
+			}
+		}
+
+	}
+}