Add option to limit render fps to game tick rate

This helps slow systems that struggle to render 2 frames per game tick.

OpenRA.Game/Game.cs

@@ -787,8 +787,12 @@ namespace OpenRA
 					logicInterval = logicWorld == OrderManager.World ? OrderManager.SuggestedTimestep : logicWorld.Timestep;
 
 				// Ideal time between screen updates
-				var maxFramerate = Settings.Graphics.CapFramerate ? Settings.Graphics.MaxFramerate.Clamp(1, 1000) : 1000;
+				var renderInterval = logicInterval;
-				var renderInterval = 1000 / maxFramerate;
+				if (!Settings.Graphics.CapFramerateToGameFps)
+				{
+					var maxFramerate = Settings.Graphics.CapFramerate ? Settings.Graphics.MaxFramerate.Clamp(1, 1000) : 1000;
+					renderInterval = 1000 / maxFramerate;
+				}
 
 				// Tick as fast as possible while restoring game saves, capping rendering at 5 FPS
 				if (OrderManager.World != null && OrderManager.World.IsLoadingGameSave)

OpenRA.Game/Settings.cs

@@ -192,6 +192,9 @@ namespace OpenRA
 		[Desc("At which frames per second to cap the framerate.")]
 		public int MaxFramerate = 60;
 
+		[Desc("Set a frame rate limit of 1 render frame per game simulation frame (overrides CapFramerate/MaxFramerate).")]
+		public bool CapFramerateToGameFps = false;
+
 		[Desc("Disable the OpenGL debug message callback feature.")]
 		public bool DisableGLDebugMessageCallback = false;
 

OpenRA.Mods.Common/Widgets/Logic/Settings/DisplaySettingsLogic.cs

@@ -139,6 +139,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			SettingsUtils.BindCheckboxPref(panel, "CURSORDOUBLE_CHECKBOX", ds, "CursorDouble");
 			SettingsUtils.BindCheckboxPref(panel, "VSYNC_CHECKBOX", ds, "VSync");
 			SettingsUtils.BindCheckboxPref(panel, "FRAME_LIMIT_CHECKBOX", ds, "CapFramerate");
+			SettingsUtils.BindCheckboxPref(panel, "FRAME_LIMIT_GAMESPEED_CHECKBOX", ds, "CapFramerateToGameFps");
 			SettingsUtils.BindIntSliderPref(panel, "FRAME_LIMIT_SLIDER", ds, "MaxFramerate");
 			SettingsUtils.BindCheckboxPref(panel, "PLAYER_STANCE_COLORS_CHECKBOX", gs, "UsePlayerStanceColors");
 			if (panel.GetOrNull<CheckboxWidget>("PAUSE_SHELLMAP_CHECKBOX") != null)
@@ -223,12 +224,14 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			restartDesc.IsVisible = () => ds.Mode != OriginalGraphicsMode || ds.VideoDisplay != OriginalVideoDisplay || ds.GLProfile != OriginalGLProfile ||
 				(ds.Mode == WindowMode.Windowed && (origWidthText != windowWidth.Text || origHeightText != windowHeight.Text));
 
+			var frameLimitGamespeedCheckbox = panel.Get<CheckboxWidget>("FRAME_LIMIT_GAMESPEED_CHECKBOX");
 			var frameLimitCheckbox = panel.Get<CheckboxWidget>("FRAME_LIMIT_CHECKBOX");
 			var frameLimitOrigLabel = frameLimitCheckbox.Text;
 			var frameLimitLabel = new CachedTransform<int, string>(fps => frameLimitOrigLabel + $" ({fps} FPS)");
 			frameLimitCheckbox.GetText = () => frameLimitLabel.Update(ds.MaxFramerate);
+			frameLimitCheckbox.IsDisabled = () => ds.CapFramerateToGameFps;
 
-			panel.Get<SliderWidget>("FRAME_LIMIT_SLIDER").IsDisabled = () => !frameLimitCheckbox.IsChecked();
+			panel.Get<SliderWidget>("FRAME_LIMIT_SLIDER").IsDisabled = () => !frameLimitCheckbox.IsChecked() || frameLimitGamespeedCheckbox.IsChecked();
 
 			// Player profile
 			var ps = Game.Settings.Player;
@@ -305,6 +308,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			{
 				ds.CapFramerate = dds.CapFramerate;
 				ds.MaxFramerate = dds.MaxFramerate;
+				ds.CapFramerateToGameFps = dds.CapFramerateToGameFps;
 				ds.GLProfile = dds.GLProfile;
 				ds.Mode = dds.Mode;
 				ds.VideoDisplay = dds.VideoDisplay;

mods/cnc/chrome/settings-display.yaml

@@ -303,6 +303,16 @@ Container@DISPLAY_PANEL:
 									Height: 20
 									Font: Regular
 									Text: Enable VSync
+						Container@FRAME_LIMIT_GAMESPEED_CHECKBOX_CONTAINER:
+							X: PARENT_RIGHT / 2 + 10
+							Y: 25
+							Width: PARENT_RIGHT / 2 - 20
+							Children:
+								Checkbox@FRAME_LIMIT_GAMESPEED_CHECKBOX:
+									Width: PARENT_RIGHT
+									Height: 20
+									Font: Regular
+									Text: Limit framerate to game tick rate
 				Container@ROW:
 					Width: PARENT_RIGHT - 24
 					Height: 50

mods/common/chrome/settings-display.yaml

@@ -312,6 +312,16 @@ Container@DISPLAY_PANEL:
 									Height: 20
 									Font: Regular
 									Text: Enable VSync
+						Container@FRAME_LIMIT_GAMESPEED_CHECKBOX_CONTAINER:
+							X: PARENT_RIGHT / 2 + 10
+							Y: 25
+							Width: PARENT_RIGHT / 2 - 20
+							Children:
+								Checkbox@FRAME_LIMIT_GAMESPEED_CHECKBOX:
+									Width: PARENT_RIGHT
+									Height: 20
+									Font: Regular
+									Text: Limit framerate to game tick rate
 				Container@ROW:
 					Width: PARENT_RIGHT - 24
 					Height: 50