feat(windows): add active monitor refresh rate detection

UI/Utilities/DisplayHelper.cs

@@ -0,0 +1,145 @@
+using Avalonia;
+using Avalonia.Controls.ApplicationLifetimes;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+
+namespace Mesen.Utilities
+{
+	public class DisplayHelper
+	{
+		[DllImport("user32.dll")]
+		private static extern IntPtr MonitorFromWindow(IntPtr hwnd, uint dwFlags);
+
+		[DllImport("user32.dll", CharSet = CharSet.Auto)]
+		private static extern bool GetMonitorInfo(IntPtr hMonitor, ref MONITORINFOEX lpmi);
+
+		[DllImport("user32.dll", CharSet = CharSet.Auto)]
+		private static extern bool EnumDisplaySettings(string? lpszDeviceName, int iModeNum, ref DEVMODE lpDevMode);
+
+		private const uint MONITOR_DEFAULTTONEAREST = 2;
+
+		[StructLayout(LayoutKind.Sequential)]
+		private struct RECT
+		{
+			public int left, top, right, bottom;
+		}
+
+		[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
+		private struct MONITORINFOEX
+		{
+			public int cbSize;
+			public RECT rcMonitor;
+			public RECT rcWork;
+			public int dwFlags;
+
+			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
+			public string szDevice;
+		}
+
+		[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
+		private struct DEVMODE
+		{
+			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
+			public string dmDeviceName;
+
+			public short dmSpecVersion;
+			public short dmDriverVersion;
+			public short dmSize;
+			public short dmDriverExtra;
+			public int dmFields;
+			public int dmPositionX;
+			public int dmPositionY;
+			public int dmDisplayOrientation;
+			public int dmDisplayFixedOutput;
+			public short dmColor;
+			public short dmDuplex;
+			public short dmYResolution;
+			public short dmTTOption;
+			public short dmCollate;
+
+			[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
+			public string dmFormName;
+
+			public short dmLogPixels;
+			public int dmBitsPerPel;
+			public int dmPelsWidth;
+			public int dmPelsHeight;
+			public int dmDisplayFlags;
+			public int dmDisplayFrequency;
+			public int dmICMMethod;
+			public int dmICMIntent;
+			public int dmMediaType;
+			public int dmDitherType;
+			public int dmReserved1;
+			public int dmReserved2;
+			public int dmPanningWidth;
+			public int dmPanningHeight;
+		}
+
+		/// <summary>
+		/// Returns an array of supported refresh rates for the monitor where the main Avalonia window currently resides.
+		/// Assumes the caller has already verified this is executing on a Windows environment.
+		/// </summary>
+		public static UInt32[] GetRefreshRatesForCurrentMonitor()
+		{
+			IntPtr hwnd = IntPtr.Zero;
+
+			// 1. Safely grab the Avalonia Main Window handle
+			if(Application.Current?.ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop) {
+				var window = desktop.MainWindow;
+				if(window != null) {
+					var platformHandle = window.TryGetPlatformHandle();
+					if(platformHandle != null) {
+						hwnd = platformHandle.Handle;
+					}
+				}
+			}
+
+			string? deviceName = null;
+
+			// 2. If we successfully got the window handle, find out which monitor it's on
+			if(hwnd != IntPtr.Zero) {
+				IntPtr hMonitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);
+				MONITORINFOEX monitorInfo = new MONITORINFOEX();
+				monitorInfo.cbSize = Marshal.SizeOf<MONITORINFOEX>();
+
+				if(GetMonitorInfo(hMonitor, ref monitorInfo)) {
+					deviceName = monitorInfo.szDevice;
+				}
+			}
+
+			// 3. Query the refresh rates (passing 'null' as deviceName falls back to primary display)
+			HashSet<UInt32> refreshRates = new HashSet<UInt32>();
+			DEVMODE vDevMode = new DEVMODE();
+			vDevMode.dmSize = (short)Marshal.SizeOf<DEVMODE>();
+
+			int modeIndex = 0;
+			while(EnumDisplaySettings(deviceName, modeIndex, ref vDevMode)) {
+				if(vDevMode.dmDisplayFrequency > 0) {
+					refreshRates.Add((UInt32)vDevMode.dmDisplayFrequency);
+				}
+
+				modeIndex++;
+			}
+
+			UInt32[] result = refreshRates.ToArray();
+			Array.Sort(result);
+			return result;
+		}
+
+		/// <summary>
+		/// Returns the lowest refresh rate that is equal to or a multiple of <paramref name="targetRate"/>.
+		/// Falls back to the highest available rate if no compatible rate is found, or if <paramref name="targetRate"/> is 0.
+		/// </summary>
+		public static UInt32 GetCompatibleRefreshRate(UInt32[] availableRates, UInt32 targetRate)
+		{
+			if(targetRate == 0) return availableRates.LastOrDefault();
+
+			var compatibleRate = availableRates.FirstOrDefault(rate => rate % targetRate == 0);
+
+			return compatibleRate == 0 ? availableRates.LastOrDefault() : compatibleRate;
+		}
+	}
+}

UI/ViewModels/VideoConfigViewModel.cs

@@ -55,6 +55,23 @@ public VideoConfigViewModel()
 			//Exclusive fullscreen is only supported on Windows currently
 			IsWindows = OperatingSystem.IsWindows();
 
+			// Detect available refresh rates on Windows and ensure the configured refresh rates are valid
+			if(IsWindows) {
+				UInt32[] monitorSupportedRefreshRates = DisplayHelper.GetRefreshRatesForCurrentMonitor();
+
+				if(monitorSupportedRefreshRates.Length > 0) {
+					AvailableRefreshRates = monitorSupportedRefreshRates;
+
+					if(!AvailableRefreshRates.Contains(Config.ExclusiveFullscreenRefreshRatePal)) {
+						Config.ExclusiveFullscreenRefreshRatePal = DisplayHelper.GetCompatibleRefreshRate(AvailableRefreshRates, Config.ExclusiveFullscreenRefreshRatePal);
+					}
+
+					if(!AvailableRefreshRates.Contains(Config.ExclusiveFullscreenRefreshRateNtsc)) {
+						Config.ExclusiveFullscreenRefreshRateNtsc = DisplayHelper.GetCompatibleRefreshRate(AvailableRefreshRates, Config.ExclusiveFullscreenRefreshRateNtsc);
+					}
+				}
+			}
+
 			//MacOS only supports the software renderer
 			IsMacOs = OperatingSystem.IsMacOS();