Add IEmuClientApi method (+Lua) for getting approximate framerate

src/BizHawk.Client.Common/Api/Classes/EmuClientApi.cs

@@ -89,6 +89,8 @@ namespace BizHawk.Client.Common
 			_mainForm.FrameSkipMessage();
 		}
 
+		public int GetApproxFramerate() => _mainForm.GetApproxFramerate();
+
 		public bool GetSoundOn() => _config.SoundEnabled;
 
 		public int GetTargetScanlineIntensity() => _config.TargetScanlineFilterIntensity;

src/BizHawk.Client.Common/Api/Interfaces/IEmuClientApi.cs

@@ -63,6 +63,9 @@ namespace BizHawk.Client.Common
 
 		void FrameSkip(int numFrames);
 
+		/// <returns>the (host) framerate, approximated from frame durations</returns>
+		int GetApproxFramerate();
+
 		bool GetSoundOn();
 
 		int GetTargetScanlineIntensity();

src/BizHawk.Client.Common/IMainFormForApi.cs

@@ -59,6 +59,9 @@ namespace BizHawk.Client.Common
 
 		void FrameSkipMessage();
 
+		/// <remarks>only referenced from <see cref="EmuClientApi"/></remarks>
+		int GetApproxFramerate();
+
 		/// <remarks>only referenced from <see cref="SaveStateApi"/></remarks>
 		void LoadQuickSave(string quickSlotName, bool suppressOSD = false);
 

src/BizHawk.Client.Common/lua/CommonLibs/ClientLuaLibrary.cs

@@ -112,6 +112,10 @@ namespace BizHawk.Client.Common
 			}
 		}
 
+		[LuaMethodExample("local sounds_terrible = client.get_approx_framerate() < 55;")]
+		[LuaMethod("get_approx_framerate", "Gets the (host) framerate, approximated from frame durations.")]
+		public int GetApproxFramerate() => APIs.EmuClient.GetApproxFramerate();
+
 		[LuaMethodExample("local incliget = client.gettargetscanlineintensity( );")]
 		[LuaMethod("gettargetscanlineintensity", "Gets the current scanline intensity setting, used for the scanline display filter")]
 		public int GetTargetScanlineIntensity() => APIs.EmuClient.GetTargetScanlineIntensity();

src/BizHawk.Client.EmuHawk/MainForm.cs

@@ -1608,6 +1608,8 @@ namespace BizHawk.Client.EmuHawk
 		private int _framesSinceLastFpsUpdate;
 		private long _timestampLastFpsUpdate;
 
+		public int GetApproxFramerate() => _lastFpsRounded;
+
 		private readonly Throttle _throttle;
 		private bool _unthrottled;