Add component for game-wide touch detection

osu.Game.Tests/Visual/Navigation/TestSceneScreenNavigation.cs

@@ -12,6 +12,7 @@ using osu.Framework.Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Input;
 using osu.Framework.Screens;
 using osu.Framework.Testing;
 using osu.Game.Beatmaps;
@@ -835,6 +836,27 @@ namespace osu.Game.Tests.Visual.Navigation
             AddAssert("exit dialog is shown", () => Game.Dependencies.Get<IDialogOverlay>().CurrentDialog is ConfirmExitDialog);
         }
 
+        [Test]
+        public void TestTouchScreenDetection()
+        {
+            AddStep("touch logo", () =>
+            {
+                var button = Game.ChildrenOfType<OsuLogo>().Single();
+                var touch = new Touch(TouchSource.Touch1, button.ScreenSpaceDrawQuad.Centre);
+                InputManager.BeginTouch(touch);
+                InputManager.EndTouch(touch);
+            });
+            AddAssert("touch screen detected active", () => Game.Dependencies.Get<SessionStatics>().Get<bool>(Static.TouchInputActive), () => Is.True);
+
+            AddStep("click settings button", () =>
+            {
+                var button = Game.ChildrenOfType<MainMenuButton>().Last();
+                InputManager.MoveMouseTo(button);
+                InputManager.Click(MouseButton.Left);
+            });
+            AddAssert("touch screen detected inactive", () => Game.Dependencies.Get<SessionStatics>().Get<bool>(Static.TouchInputActive), () => Is.False);
+        }
+
         private Func<Player> playToResults()
         {
             var player = playToCompletion();

osu.Game/Configuration/SessionStatics.cs

@@ -4,6 +4,7 @@
 #nullable disable
 
 using osu.Game.Graphics.UserInterface;
+using osu.Game.Input;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Overlays;
 using osu.Game.Overlays.Mods;
@@ -24,6 +25,7 @@ namespace osu.Game.Configuration
             SetDefault(Static.LastHoverSoundPlaybackTime, (double?)null);
             SetDefault(Static.LastModSelectPanelSamplePlaybackTime, (double?)null);
             SetDefault<APISeasonalBackgrounds>(Static.SeasonalBackgrounds, null);
+            SetDefault(Static.TouchInputActive, false);
         }
 
         /// <summary>
@@ -63,6 +65,12 @@ namespace osu.Game.Configuration
         /// The last playback time in milliseconds of an on/off sample (from <see cref="ModSelectPanel"/>).
         /// Used to debounce <see cref="ModSelectPanel"/> on/off sounds game-wide to avoid volume saturation, especially in activating mod presets with many mods.
         /// </summary>
-        LastModSelectPanelSamplePlaybackTime
+        LastModSelectPanelSamplePlaybackTime,
+
+        /// <summary>
+        /// Whether the last positional input received was a touch input.
+        /// Used in touchscreen detection scenarios (<see cref="TouchInputInterceptor"/>).
+        /// </summary>
+        TouchInputActive,
     }
 }

osu.Game/Input/TouchInputInterceptor.cs

@@ -0,0 +1,41 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Input.Events;
+using osu.Framework.Input.StateChanges;
+using osu.Game.Configuration;
+using osuTK;
+
+namespace osu.Game.Input
+{
+    /// <summary>
+    /// Intercepts all positional input events and sets the appropriate <see cref="Static.TouchInputActive"/> value
+    /// for consumption by particular game screens.
+    /// </summary>
+    public partial class TouchInputInterceptor : Component
+    {
+        public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => true;
+
+        [Resolved]
+        private SessionStatics statics { get; set; } = null!;
+
+        protected override bool Handle(UIEvent e)
+        {
+            switch (e)
+            {
+                case MouseEvent:
+                    if (e.CurrentState.Mouse.LastSource is not ISourcedFromTouch)
+                        statics.SetValue(Static.TouchInputActive, false);
+                    break;
+
+                case TouchEvent:
+                    statics.SetValue(Static.TouchInputActive, true);
+                    break;
+            }
+
+            return false;
+        }
+    }
+}

osu.Game/OsuGameBase.cs

@@ -407,6 +407,8 @@ namespace osu.Game
                 })
             });
 
+            base.Content.Add(new TouchInputInterceptor());
+
             KeyBindingStore = new RealmKeyBindingStore(realm, keyCombinationProvider);
             KeyBindingStore.Register(globalBindings, RulesetStore.AvailableRulesets);