Issue #735: Add sound channel toggling on mgba

BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/LibmGBA.cs

@@ -115,5 +115,19 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 
 		[DllImport(dll, CallingConvention = cc)]
 		public static extern void BizSetLayerMask(IntPtr ctx, Layers mask);
+
+		[Flags]
+		public enum Sounds : int
+		{
+			CH0 = 1,
+			CH1 = 2,
+			CH2 = 4,
+			CH3 = 8,
+			CHA = 16,
+			CHB = 32
+		}
+
+		[DllImport(dll, CallingConvention = cc)]
+		public static extern void BizSetSoundMask(IntPtr ctx, Sounds mask);
 	}
 }

BizHawk.Emulation.Cores/Consoles/Nintendo/GBA/MGBAHawk.cs

@@ -476,6 +476,16 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			if (o.DisplayBG3) mask |= LibmGBA.Layers.BG3;
 			if (o.DisplayOBJ) mask |= LibmGBA.Layers.OBJ;
 			LibmGBA.BizSetLayerMask(_core, mask);
+
+			LibmGBA.Sounds smask = 0;
+			if (o.PlayCh0) smask |= LibmGBA.Sounds.CH0;
+			if (o.PlayCh1) smask |= LibmGBA.Sounds.CH1;
+			if (o.PlayCh2) smask |= LibmGBA.Sounds.CH2;
+			if (o.PlayCh3) smask |= LibmGBA.Sounds.CH3;
+			if (o.PlayChA) smask |= LibmGBA.Sounds.CHA;
+			if (o.PlayChB) smask |= LibmGBA.Sounds.CHB;
+			LibmGBA.BizSetSoundMask(_core, smask);
+
 			_settings = o;
 			return false;
 		}
@@ -495,6 +505,19 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBA
 			[DefaultValue(true)]
 			public bool DisplayOBJ { get; set; }
 
+			[DefaultValue(true)]
+			public bool PlayCh0 { get; set; }
+			[DefaultValue(true)]
+			public bool PlayCh1 { get; set; }
+			[DefaultValue(true)]
+			public bool PlayCh2 { get; set; }
+			[DefaultValue(true)]
+			public bool PlayCh3 { get; set; }
+			[DefaultValue(true)]
+			public bool PlayChA { get; set; }
+			[DefaultValue(true)]
+			public bool PlayChB { get; set; }
+
 			public Settings Clone()
 			{
 				return (Settings)MemberwiseClone();