Merge pull request #22654 from ItsShamed/gameplay/key-counter-abstraction

Introduce common structure for key counters

osu.Game.Rulesets.Osu.Tests/TestSceneOsuTouchInput.cs

@@ -21,7 +21,7 @@ using osu.Game.Configuration;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Rulesets.Osu.Objects.Drawables;
 using osu.Game.Rulesets.Osu.UI.Cursor;
-using osu.Game.Screens.Play;
+using osu.Game.Screens.Play.HUD;
 using osu.Game.Tests.Visual;
 using osuTK;
 using osuTK.Graphics;
@@ -34,9 +34,9 @@ namespace osu.Game.Rulesets.Osu.Tests
         [Resolved]
         private OsuConfigManager config { get; set; } = null!;
 
-        private TestActionKeyCounter leftKeyCounter = null!;
+        private DefaultKeyCounter leftKeyCounter = null!;
 
-        private TestActionKeyCounter rightKeyCounter = null!;
+        private DefaultKeyCounter rightKeyCounter = null!;
 
         private OsuInputManager osuInputManager = null!;
 
@@ -59,14 +59,14 @@ namespace osu.Game.Rulesets.Osu.Tests
                             Origin = Anchor.Centre,
                             Children = new Drawable[]
                             {
-                                leftKeyCounter = new TestActionKeyCounter(OsuAction.LeftButton)
+                                leftKeyCounter = new DefaultKeyCounter(new TestActionKeyCounterTrigger(OsuAction.LeftButton))
                                 {
                                     Anchor = Anchor.Centre,
                                     Origin = Anchor.CentreRight,
                                     Depth = float.MinValue,
                                     X = -100,
                                 },
-                                rightKeyCounter = new TestActionKeyCounter(OsuAction.RightButton)
+                                rightKeyCounter = new DefaultKeyCounter(new TestActionKeyCounterTrigger(OsuAction.RightButton))
                                 {
                                     Anchor = Anchor.Centre,
                                     Origin = Anchor.CentreLeft,
@@ -598,8 +598,8 @@ namespace osu.Game.Rulesets.Osu.Tests
 
         private void assertKeyCounter(int left, int right)
         {
-            AddAssert($"The left key was pressed {left} times", () => leftKeyCounter.CountPresses, () => Is.EqualTo(left));
+            AddAssert($"The left key was pressed {left} times", () => leftKeyCounter.CountPresses.Value, () => Is.EqualTo(left));
-            AddAssert($"The right key was pressed {right} times", () => rightKeyCounter.CountPresses, () => Is.EqualTo(right));
+            AddAssert($"The right key was pressed {right} times", () => rightKeyCounter.CountPresses.Value, () => Is.EqualTo(right));
         }
 
         private void releaseAllTouches()
@@ -615,11 +615,11 @@ namespace osu.Game.Rulesets.Osu.Tests
         private void checkNotPressed(OsuAction action) => AddAssert($"Not pressing {action}", () => !osuInputManager.PressedActions.Contains(action));
         private void checkPressed(OsuAction action) => AddAssert($"Is pressing {action}", () => osuInputManager.PressedActions.Contains(action));
 
-        public partial class TestActionKeyCounter : KeyCounter, IKeyBindingHandler<OsuAction>
+        public partial class TestActionKeyCounterTrigger : InputTrigger, IKeyBindingHandler<OsuAction>
         {
             public OsuAction Action { get; }
 
-            public TestActionKeyCounter(OsuAction action)
+            public TestActionKeyCounterTrigger(OsuAction action)
                 : base(action.ToString())
             {
                 Action = action;
@@ -629,8 +629,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             {
                 if (e.Action == Action)
                 {
-                    IsLit = true;
+                    Activate();
-                    Increment();
                 }
 
                 return false;
@@ -638,7 +637,8 @@ namespace osu.Game.Rulesets.Osu.Tests
 
             public void OnReleased(KeyBindingReleaseEvent<OsuAction> e)
             {
-                if (e.Action == Action) IsLit = false;
+                if (e.Action == Action)
+                    Deactivate();
             }
         }
 

osu.Game.Tests/Visual/Gameplay/TestSceneAutoplay.cs

@@ -35,14 +35,14 @@ namespace osu.Game.Tests.Visual.Gameplay
             var referenceBeatmap = CreateBeatmap(new OsuRuleset().RulesetInfo);
 
             AddUntilStep("score above zero", () => Player.ScoreProcessor.TotalScore.Value > 0);
-            AddUntilStep("key counter counted keys", () => Player.HUDOverlay.KeyCounter.Children.Any(kc => kc.CountPresses > 2));
+            AddUntilStep("key counter counted keys", () => Player.HUDOverlay.KeyCounter.Counters.Any(kc => kc.CountPresses.Value > 2));
 
             seekTo(referenceBeatmap.Breaks[0].StartTime);
-            AddAssert("keys not counting", () => !Player.HUDOverlay.KeyCounter.IsCounting);
+            AddAssert("keys not counting", () => !Player.HUDOverlay.KeyCounter.IsCounting.Value);
             AddAssert("overlay displays 100% accuracy", () => Player.BreakOverlay.ChildrenOfType<BreakInfo>().Single().AccuracyDisplay.Current.Value == 1);
 
             AddStep("rewind", () => Player.GameplayClockContainer.Seek(-80000));
-            AddUntilStep("key counter reset", () => Player.HUDOverlay.KeyCounter.Children.All(kc => kc.CountPresses == 0));
+            AddUntilStep("key counter reset", () => Player.HUDOverlay.KeyCounter.Counters.All(kc => kc.CountPresses.Value == 0));
 
             seekTo(referenceBeatmap.HitObjects[^1].GetEndTime());
             AddUntilStep("results displayed", () => getResultsScreen()?.IsLoaded == true);

osu.Game.Tests/Visual/Gameplay/TestSceneGameplayRewinding.cs

@@ -31,11 +31,11 @@ namespace osu.Game.Tests.Visual.Gameplay
             AddUntilStep("wait for track to start running", () => Beatmap.Value.Track.IsRunning);
             addSeekStep(3000);
             AddAssert("all judged", () => Player.DrawableRuleset.Playfield.AllHitObjects.All(h => h.Judged));
-            AddUntilStep("key counter counted keys", () => Player.HUDOverlay.KeyCounter.Children.Select(kc => kc.CountPresses).Sum() == 15);
+            AddUntilStep("key counter counted keys", () => Player.HUDOverlay.KeyCounter.Counters.Select(kc => kc.CountPresses.Value).Sum() == 15);
             AddStep("clear results", () => Player.Results.Clear());
             addSeekStep(0);
             AddAssert("none judged", () => Player.DrawableRuleset.Playfield.AllHitObjects.All(h => !h.Judged));
-            AddUntilStep("key counters reset", () => Player.HUDOverlay.KeyCounter.Children.All(kc => kc.CountPresses == 0));
+            AddUntilStep("key counters reset", () => Player.HUDOverlay.KeyCounter.Counters.All(kc => kc.CountPresses.Value == 0));
             AddAssert("no results triggered", () => Player.Results.Count == 0);
         }
 

osu.Game.Tests/Visual/Gameplay/TestSceneHUDOverlay.cs

@@ -45,7 +45,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         // best way to check without exposing.
         private Drawable hideTarget => hudOverlay.KeyCounter;
-        private FillFlowContainer<KeyCounter> keyCounterFlow => hudOverlay.KeyCounter.ChildrenOfType<FillFlowContainer<KeyCounter>>().First();
+        private Drawable keyCounterFlow => hudOverlay.KeyCounter.ChildrenOfType<FillFlowContainer<DefaultKeyCounter>>().Single();
 
         [BackgroundDependencyLoader]
         private void load()
@@ -267,7 +267,7 @@ namespace osu.Game.Tests.Visual.Gameplay
                 hudOverlay = new HUDOverlay(null, Array.Empty<Mod>());
 
                 // Add any key just to display the key counter visually.
-                hudOverlay.KeyCounter.Add(new KeyCounterKeyboard(Key.Space));
+                hudOverlay.KeyCounter.Add(new KeyCounterKeyboardTrigger(Key.Space));
 
                 scoreProcessor.Combo.Value = 1;
 

osu.Game.Tests/Visual/Gameplay/TestSceneKeyCounter.cs

@@ -7,7 +7,7 @@ using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Graphics;
 using osu.Framework.Utils;
-using osu.Game.Screens.Play;
+using osu.Game.Screens.Play.HUD;
 using osuTK.Input;
 
 namespace osu.Game.Tests.Visual.Gameplay
@@ -17,28 +17,29 @@ namespace osu.Game.Tests.Visual.Gameplay
     {
         public TestSceneKeyCounter()
         {
-            KeyCounterKeyboard testCounter;
+            KeyCounterDisplay kc = new DefaultKeyCounterDisplay
-
-            KeyCounterDisplay kc = new KeyCounterDisplay
             {
                 Origin = Anchor.Centre,
                 Anchor = Anchor.Centre,
-                Children = new KeyCounter[]
-                {
-                    testCounter = new KeyCounterKeyboard(Key.X),
-                    new KeyCounterKeyboard(Key.X),
-                    new KeyCounterMouse(MouseButton.Left),
-                    new KeyCounterMouse(MouseButton.Right),
-                },
             };
 
+            kc.AddRange(new InputTrigger[]
+            {
+                new KeyCounterKeyboardTrigger(Key.X),
+                new KeyCounterKeyboardTrigger(Key.X),
+                new KeyCounterMouseTrigger(MouseButton.Left),
+                new KeyCounterMouseTrigger(MouseButton.Right),
+            });
+
+            var testCounter = (DefaultKeyCounter)kc.Counters.First();
+
             AddStep("Add random", () =>
             {
                 Key key = (Key)((int)Key.A + RNG.Next(26));
-                kc.Add(new KeyCounterKeyboard(key));
+                kc.Add(new KeyCounterKeyboardTrigger(key));
             });
 
-            Key testKey = ((KeyCounterKeyboard)kc.Children.First()).Key;
+            Key testKey = ((KeyCounterKeyboardTrigger)kc.Counters.First().Trigger).Key;
 
             void addPressKeyStep()
             {
@@ -46,12 +47,12 @@ namespace osu.Game.Tests.Visual.Gameplay
             }
 
             addPressKeyStep();
-            AddAssert($"Check {testKey} counter after keypress", () => testCounter.CountPresses == 1);
+            AddAssert($"Check {testKey} counter after keypress", () => testCounter.CountPresses.Value == 1);
             addPressKeyStep();
-            AddAssert($"Check {testKey} counter after keypress", () => testCounter.CountPresses == 2);
+            AddAssert($"Check {testKey} counter after keypress", () => testCounter.CountPresses.Value == 2);
-            AddStep("Disable counting", () => testCounter.IsCounting = false);
+            AddStep("Disable counting", () => testCounter.IsCounting.Value = false);
             addPressKeyStep();
-            AddAssert($"Check {testKey} count has not changed", () => testCounter.CountPresses == 2);
+            AddAssert($"Check {testKey} count has not changed", () => testCounter.CountPresses.Value == 2);
 
             Add(kc);
         }

osu.Game.Tests/Visual/Gameplay/TestSceneReplay.cs

@@ -27,7 +27,7 @@ namespace osu.Game.Tests.Visual.Gameplay
         protected override void AddCheckSteps()
         {
             AddUntilStep("score above zero", () => ((ScoreAccessibleReplayPlayer)Player).ScoreProcessor.TotalScore.Value > 0);
-            AddUntilStep("key counter counted keys", () => ((ScoreAccessibleReplayPlayer)Player).HUDOverlay.KeyCounter.Children.Any(kc => kc.CountPresses > 0));
+            AddUntilStep("key counter counted keys", () => ((ScoreAccessibleReplayPlayer)Player).HUDOverlay.KeyCounter.Counters.Any(kc => kc.CountPresses.Value > 0));
             AddAssert("cannot fail", () => !((ScoreAccessibleReplayPlayer)Player).AllowFail);
         }
 

osu.Game.Tests/Visual/Gameplay/TestSceneSkinEditorMultipleSkins.cs

@@ -14,6 +14,7 @@ using osu.Game.Rulesets.Osu;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Screens.Edit;
 using osu.Game.Screens.Play;
+using osu.Game.Screens.Play.HUD;
 using osu.Game.Tests.Gameplay;
 using osuTK.Input;
 
@@ -57,7 +58,7 @@ namespace osu.Game.Tests.Visual.Gameplay
                     };
 
                     // Add any key just to display the key counter visually.
-                    hudOverlay.KeyCounter.Add(new KeyCounterKeyboard(Key.Space));
+                    hudOverlay.KeyCounter.Add(new KeyCounterKeyboardTrigger(Key.Space));
                     scoreProcessor.Combo.Value = 1;
 
                     return new Container

osu.Game.Tests/Visual/Gameplay/TestSceneSkinnableHUDOverlay.cs

@@ -18,6 +18,7 @@ using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Screens.Play;
+using osu.Game.Screens.Play.HUD;
 using osu.Game.Tests.Gameplay;
 using osuTK.Input;
 
@@ -43,7 +44,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         // best way to check without exposing.
         private Drawable hideTarget => hudOverlay.KeyCounter;
-        private FillFlowContainer<KeyCounter> keyCounterFlow => hudOverlay.KeyCounter.ChildrenOfType<FillFlowContainer<KeyCounter>>().First();
+        private Drawable keyCounterFlow => hudOverlay.KeyCounter.ChildrenOfType<FillFlowContainer<DefaultKeyCounter>>().Single();
 
         [Test]
         public void TestComboCounterIncrementing()
@@ -88,7 +89,7 @@ namespace osu.Game.Tests.Visual.Gameplay
                     hudOverlay = new HUDOverlay(null, Array.Empty<Mod>());
 
                     // Add any key just to display the key counter visually.
-                    hudOverlay.KeyCounter.Add(new KeyCounterKeyboard(Key.Space));
+                    hudOverlay.KeyCounter.Add(new KeyCounterKeyboardTrigger(Key.Space));
 
                     action?.Invoke(hudOverlay);
 

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

@@ -14,6 +14,7 @@ using osu.Game.Graphics.UserInterface;
 using osu.Game.Input.Bindings;
 using osu.Game.Overlays.Settings.Sections.Input;
 using osu.Game.Screens.Play;
+using osu.Game.Screens.Play.HUD;
 using osu.Game.Screens.Select;
 using osu.Game.Tests.Beatmaps.IO;
 using osuTK.Input;
@@ -69,10 +70,10 @@ namespace osu.Game.Tests.Visual.Navigation
             AddUntilStep("wait for gameplay", () => player?.IsBreakTime.Value == false);
 
             AddStep("press 'z'", () => InputManager.Key(Key.Z));
-            AddAssert("key counter didn't increase", () => keyCounter.CountPresses == 0);
+            AddAssert("key counter didn't increase", () => keyCounter.CountPresses.Value == 0);
 
             AddStep("press 's'", () => InputManager.Key(Key.S));
-            AddAssert("key counter did increase", () => keyCounter.CountPresses == 1);
+            AddAssert("key counter did increase", () => keyCounter.CountPresses.Value == 1);
         }
 
         private KeyBindingsSubsection osuBindingSubsection => keyBindingPanel

osu.Game/Rulesets/UI/DrawableRuleset.cs

@@ -30,6 +30,7 @@ using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Scoring;
 using osu.Game.Screens.Play;
+using osu.Game.Screens.Play.HUD;
 using osu.Game.Screens.Play.HUD.ClicksPerSecond;
 using osuTK;
 

osu.Game/Rulesets/UI/RulesetInputManager.cs

@@ -19,7 +19,7 @@ using osu.Game.Input;
 using osu.Game.Input.Bindings;
 using osu.Game.Input.Handlers;
 using osu.Game.Rulesets.Scoring;
-using osu.Game.Screens.Play;
+using osu.Game.Screens.Play.HUD;
 using osu.Game.Screens.Play.HUD.ClicksPerSecond;
 using static osu.Game.Input.Handlers.ReplayInputHandler;
 
@@ -169,7 +169,7 @@ namespace osu.Game.Rulesets.UI
                                                    .Select(b => b.GetAction<T>())
                                                    .Distinct()
                                                    .OrderBy(action => action)
-                                                   .Select(action => new KeyCounterAction<T>(action)));
+                                                   .Select(action => new KeyCounterActionTrigger<T>(action)));
         }
 
         private partial class ActionReceptor : KeyCounterDisplay.Receptor, IKeyBindingHandler<T>
@@ -179,11 +179,14 @@ namespace osu.Game.Rulesets.UI
             {
             }
 
-            public bool OnPressed(KeyBindingPressEvent<T> e) => Target.Children.OfType<KeyCounterAction<T>>().Any(c => c.OnPressed(e.Action, Clock.Rate >= 0));
+            public bool OnPressed(KeyBindingPressEvent<T> e) => Target.Counters.Where(c => c.Trigger is KeyCounterActionTrigger<T>)
+                                                                      .Select(c => (KeyCounterActionTrigger<T>)c.Trigger)
+                                                                      .Any(c => c.OnPressed(e.Action, Clock.Rate >= 0));
 
             public void OnReleased(KeyBindingReleaseEvent<T> e)
             {
-                foreach (var c in Target.Children.OfType<KeyCounterAction<T>>())
+                foreach (var c
+                         in Target.Counters.Where(c => c.Trigger is KeyCounterActionTrigger<T>).Select(c => (KeyCounterActionTrigger<T>)c.Trigger))
                     c.OnReleased(e.Action, Clock.Rate >= 0);
             }
         }

osu.Game/Screens/Play/HUD/DefaultKeyCounter.cs

@@ -1,8 +1,6 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// 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.
 
-#nullable disable
-
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -13,70 +11,23 @@ using osu.Game.Graphics.Sprites;
 using osuTK;
 using osuTK.Graphics;
 
-namespace osu.Game.Screens.Play
+namespace osu.Game.Screens.Play.HUD
 {
-    public abstract partial class KeyCounter : Container
+    public partial class DefaultKeyCounter : KeyCounter
     {
-        private Sprite buttonSprite;
+        private Sprite buttonSprite = null!;
-        private Sprite glowSprite;
+        private Sprite glowSprite = null!;
-        private Container textLayer;
+        private Container textLayer = null!;
-        private SpriteText countSpriteText;
+        private SpriteText countSpriteText = null!;
-
-        public bool IsCounting { get; set; } = true;
-        private int countPresses;
-
-        public int CountPresses
-        {
-            get => countPresses;
-            private set
-            {
-                if (countPresses != value)
-                {
-                    countPresses = value;
-                    countSpriteText.Text = value.ToString(@"#,0");
-                }
-            }
-        }
-
-        private bool isLit;
-
-        public bool IsLit
-        {
-            get => isLit;
-            protected set
-            {
-                if (isLit != value)
-                {
-                    isLit = value;
-                    updateGlowSprite(value);
-                }
-            }
-        }
-
-        public void Increment()
-        {
-            if (!IsCounting)
-                return;
-
-            CountPresses++;
-        }
-
-        public void Decrement()
-        {
-            if (!IsCounting)
-                return;
-
-            CountPresses--;
-        }
 
         //further: change default values here and in KeyCounterCollection if needed, instead of passing them in every constructor
         public Color4 KeyDownTextColor { get; set; } = Color4.DarkGray;
         public Color4 KeyUpTextColor { get; set; } = Color4.White;
         public double FadeTime { get; set; }
 
-        protected KeyCounter(string name)
+        public DefaultKeyCounter(InputTrigger trigger)
+            : base(trigger)
         {
-            Name = name;
         }
 
         [BackgroundDependencyLoader(true)]
@@ -116,7 +67,7 @@ namespace osu.Game.Screens.Play
                         },
                         countSpriteText = new OsuSpriteText
                         {
-                            Text = CountPresses.ToString(@"#,0"),
+                            Text = CountPresses.Value.ToString(@"#,0"),
                             Anchor = Anchor.Centre,
                             Origin = Anchor.Centre,
                             RelativePositionAxes = Axes.Both,
@@ -130,6 +81,9 @@ namespace osu.Game.Screens.Play
             // so the size can be changing between buttonSprite and glowSprite.
             Height = buttonSprite.DrawHeight;
             Width = buttonSprite.DrawWidth;
+
+            IsActive.BindValueChanged(e => updateGlowSprite(e.NewValue), true);
+            CountPresses.BindValueChanged(e => countSpriteText.Text = e.NewValue.ToString(@"#,0"), true);
         }
 
         private void updateGlowSprite(bool show)

osu.Game/Screens/Play/HUD/DefaultKeyCounterDisplay.cs

@@ -0,0 +1,83 @@
+// 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 System.Collections.Generic;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osuTK.Graphics;
+
+namespace osu.Game.Screens.Play.HUD
+{
+    public partial class DefaultKeyCounterDisplay : KeyCounterDisplay
+    {
+        private const int duration = 100;
+        private const double key_fade_time = 80;
+
+        private readonly FillFlowContainer<DefaultKeyCounter> keyFlow;
+
+        public override IEnumerable<KeyCounter> Counters => keyFlow;
+
+        public DefaultKeyCounterDisplay()
+        {
+            InternalChild = keyFlow = new FillFlowContainer<DefaultKeyCounter>
+            {
+                Direction = FillDirection.Horizontal,
+                AutoSizeAxes = Axes.Both,
+                Alpha = 0,
+            };
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            // Don't use autosize as it will shrink to zero when KeyFlow is hidden.
+            // In turn this can cause the display to be masked off screen and never become visible again.
+            Size = keyFlow.Size;
+        }
+
+        public override void Add(InputTrigger trigger) =>
+            keyFlow.Add(new DefaultKeyCounter(trigger)
+            {
+                FadeTime = key_fade_time,
+                KeyDownTextColor = KeyDownTextColor,
+                KeyUpTextColor = KeyUpTextColor,
+            });
+
+        protected override void UpdateVisibility() =>
+            // Isolate changing visibility of the key counters from fading this component.
+            keyFlow.FadeTo(AlwaysVisible.Value || ConfigVisibility.Value ? 1 : 0, duration);
+
+        private Color4 keyDownTextColor = Color4.DarkGray;
+
+        public Color4 KeyDownTextColor
+        {
+            get => keyDownTextColor;
+            set
+            {
+                if (value != keyDownTextColor)
+                {
+                    keyDownTextColor = value;
+                    foreach (var child in keyFlow)
+                        child.KeyDownTextColor = value;
+                }
+            }
+        }
+
+        private Color4 keyUpTextColor = Color4.White;
+
+        public Color4 KeyUpTextColor
+        {
+            get => keyUpTextColor;
+            set
+            {
+                if (value != keyUpTextColor)
+                {
+                    keyUpTextColor = value;
+                    foreach (var child in keyFlow)
+                        child.KeyUpTextColor = value;
+                }
+            }
+        }
+    }
+}

osu.Game/Screens/Play/HUD/InputTrigger.cs

@@ -0,0 +1,37 @@
+// 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.Graphics;
+
+namespace osu.Game.Screens.Play.HUD
+{
+    /// <summary>
+    /// An event trigger which can be used with <see cref="KeyCounter"/> to create visual tracking of button/key presses.
+    /// </summary>
+    public abstract partial class InputTrigger : Component
+    {
+        /// <summary>
+        /// Callback to invoke when the associated input has been activated.
+        /// </summary>
+        /// <param name="forwardPlayback">Whether gameplay is progressing in the forward direction time-wise.</param>
+        public delegate void OnActivateCallback(bool forwardPlayback);
+
+        /// <summary>
+        /// Callback to invoke when the associated input has been deactivated.
+        /// </summary>
+        /// <param name="forwardPlayback">Whether gameplay is progressing in the forward direction time-wise.</param>
+        public delegate void OnDeactivateCallback(bool forwardPlayback);
+
+        public event OnActivateCallback? OnActivate;
+        public event OnDeactivateCallback? OnDeactivate;
+
+        protected InputTrigger(string name)
+        {
+            Name = name;
+        }
+
+        protected void Activate(bool forwardPlayback = true) => OnActivate?.Invoke(forwardPlayback);
+
+        protected void Deactivate(bool forwardPlayback = true) => OnDeactivate?.Invoke(forwardPlayback);
+    }
+}

osu.Game/Screens/Play/HUD/KeyCounter.cs

@@ -0,0 +1,98 @@
+// 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.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+
+namespace osu.Game.Screens.Play.HUD
+{
+    /// <summary>
+    /// An individual key display which is intended to be displayed within a <see cref="KeyCounterDisplay"/>.
+    /// </summary>
+    public abstract partial class KeyCounter : Container
+    {
+        /// <summary>
+        /// The <see cref="InputTrigger"/> which activates and deactivates this <see cref="KeyCounter"/>.
+        /// </summary>
+        public readonly InputTrigger Trigger;
+
+        /// <summary>
+        /// Whether the actions reported by <see cref="Trigger"/> should be counted.
+        /// </summary>
+        public Bindable<bool> IsCounting { get; } = new BindableBool(true);
+
+        private readonly Bindable<int> countPresses = new BindableInt
+        {
+            MinValue = 0
+        };
+
+        /// <summary>
+        /// The current count of registered key presses.
+        /// </summary>
+        public IBindable<int> CountPresses => countPresses;
+
+        private readonly Container content;
+
+        protected override Container<Drawable> Content => content;
+
+        /// <summary>
+        /// Whether this <see cref="KeyCounter"/> is currently in the "activated" state because the associated key is currently pressed.
+        /// </summary>
+        protected readonly Bindable<bool> IsActive = new BindableBool();
+
+        protected KeyCounter(InputTrigger trigger)
+        {
+            InternalChildren = new Drawable[]
+            {
+                content = new Container
+                {
+                    RelativeSizeAxes = Axes.Both
+                },
+                Trigger = trigger,
+            };
+
+            Trigger.OnActivate += Activate;
+            Trigger.OnDeactivate += Deactivate;
+
+            Name = trigger.Name;
+        }
+
+        private void increment()
+        {
+            if (!IsCounting.Value)
+                return;
+
+            countPresses.Value++;
+        }
+
+        private void decrement()
+        {
+            if (!IsCounting.Value)
+                return;
+
+            countPresses.Value--;
+        }
+
+        protected virtual void Activate(bool forwardPlayback = true)
+        {
+            IsActive.Value = true;
+            if (forwardPlayback)
+                increment();
+        }
+
+        protected virtual void Deactivate(bool forwardPlayback = true)
+        {
+            IsActive.Value = false;
+            if (!forwardPlayback)
+                decrement();
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            Trigger.OnActivate -= Activate;
+            Trigger.OnDeactivate -= Deactivate;
+        }
+    }
+}

osu.Game/Screens/Play/HUD/KeyCounterActionTrigger.cs

@@ -1,18 +1,16 @@
 // 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.
 
-#nullable disable
-
 using System.Collections.Generic;
 
-namespace osu.Game.Screens.Play
+namespace osu.Game.Screens.Play.HUD
 {
-    public partial class KeyCounterAction<T> : KeyCounter
+    public partial class KeyCounterActionTrigger<T> : InputTrigger
         where T : struct
     {
         public T Action { get; }
 
-        public KeyCounterAction(T action)
+        public KeyCounterActionTrigger(T action)
             : base($"B{(int)(object)action + 1}")
         {
             Action = action;
@@ -23,9 +21,7 @@ namespace osu.Game.Screens.Play
             if (!EqualityComparer<T>.Default.Equals(action, Action))
                 return false;
 
-            IsLit = true;
+            Activate(forwards);
-            if (forwards)
-                Increment();
             return false;
         }
 
@@ -34,9 +30,7 @@ namespace osu.Game.Screens.Play
             if (!EqualityComparer<T>.Default.Equals(action, Action))
                 return;
 
-            IsLit = false;
+            Deactivate(forwards);
-            if (!forwards)
-                Decrement();
         }
     }
 }

osu.Game/Screens/Play/HUD/KeyCounterDisplay.cs

@@ -0,0 +1,109 @@
+// 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 System;
+using System.Collections.Generic;
+using System.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Input.Events;
+using osu.Game.Configuration;
+using osuTK;
+
+namespace osu.Game.Screens.Play.HUD
+{
+    /// <summary>
+    /// A flowing display of all gameplay keys. Individual keys can be added using <see cref="InputTrigger"/> implementations.
+    /// </summary>
+    public abstract partial class KeyCounterDisplay : CompositeDrawable
+    {
+        /// <summary>
+        /// Whether the key counter should be visible regardless of the configuration value.
+        /// This is true by default, but can be changed.
+        /// </summary>
+        public Bindable<bool> AlwaysVisible { get; } = new Bindable<bool>(true);
+
+        /// <summary>
+        /// The <see cref="KeyCounter"/>s contained in this <see cref="KeyCounterDisplay"/>.
+        /// </summary>
+        public abstract IEnumerable<KeyCounter> Counters { get; }
+
+        /// <summary>
+        /// Whether the actions reported by all <see cref="InputTrigger"/>s within this <see cref="KeyCounterDisplay"/> should be counted.
+        /// </summary>
+        public Bindable<bool> IsCounting { get; } = new BindableBool(true);
+
+        protected readonly Bindable<bool> ConfigVisibility = new Bindable<bool>();
+
+        protected abstract void UpdateVisibility();
+
+        private Receptor? receptor;
+
+        public void SetReceptor(Receptor receptor)
+        {
+            if (this.receptor != null)
+                throw new InvalidOperationException("Cannot set a new receptor when one is already active");
+
+            this.receptor = receptor;
+        }
+
+        /// <summary>
+        /// Add a <see cref="InputTrigger"/> to this display.
+        /// </summary>
+        public abstract void Add(InputTrigger trigger);
+
+        /// <summary>
+        /// Add a range of <see cref="InputTrigger"/> to this display.
+        /// </summary>
+        public void AddRange(IEnumerable<InputTrigger> triggers) => triggers.ForEach(Add);
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            config.BindWith(OsuSetting.KeyOverlay, ConfigVisibility);
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            AlwaysVisible.BindValueChanged(_ => UpdateVisibility());
+            ConfigVisibility.BindValueChanged(_ => UpdateVisibility(), true);
+        }
+
+        public override bool HandleNonPositionalInput => receptor == null;
+
+        public override bool HandlePositionalInput => receptor == null;
+
+        public partial class Receptor : Drawable
+        {
+            protected readonly KeyCounterDisplay Target;
+
+            public Receptor(KeyCounterDisplay target)
+            {
+                RelativeSizeAxes = Axes.Both;
+                Depth = float.MinValue;
+                Target = target;
+            }
+
+            public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => true;
+
+            protected override bool Handle(UIEvent e)
+            {
+                switch (e)
+                {
+                    case KeyDownEvent:
+                    case KeyUpEvent:
+                    case MouseDownEvent:
+                    case MouseUpEvent:
+                        return Target.InternalChildren.Any(c => c.TriggerEvent(e));
+                }
+
+                return base.Handle(e);
+            }
+        }
+    }
+}

osu.Game/Screens/Play/HUD/KeyCounterKeyboardTrigger.cs

@@ -1,18 +1,16 @@
 // 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.
 
-#nullable disable
-
 using osu.Framework.Input.Events;
 using osuTK.Input;
 
-namespace osu.Game.Screens.Play
+namespace osu.Game.Screens.Play.HUD
 {
-    public partial class KeyCounterKeyboard : KeyCounter
+    public partial class KeyCounterKeyboardTrigger : InputTrigger
     {
         public Key Key { get; }
 
-        public KeyCounterKeyboard(Key key)
+        public KeyCounterKeyboardTrigger(Key key)
             : base(key.ToString())
         {
             Key = key;
@@ -22,8 +20,7 @@ namespace osu.Game.Screens.Play
         {
             if (e.Key == Key)
             {
-                IsLit = true;
+                Activate();
-                Increment();
             }
 
             return base.OnKeyDown(e);
@@ -31,7 +28,9 @@ namespace osu.Game.Screens.Play
 
         protected override void OnKeyUp(KeyUpEvent e)
         {
-            if (e.Key == Key) IsLit = false;
+            if (e.Key == Key)
+                Deactivate();
+
             base.OnKeyUp(e);
         }
     }

osu.Game/Screens/Play/HUD/KeyCounterMouseTrigger.cs

@@ -1,19 +1,17 @@
 // 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.
 
-#nullable disable
-
 using osu.Framework.Input.Events;
-using osuTK.Input;
 using osuTK;
+using osuTK.Input;
 
-namespace osu.Game.Screens.Play
+namespace osu.Game.Screens.Play.HUD
 {
-    public partial class KeyCounterMouse : KeyCounter
+    public partial class KeyCounterMouseTrigger : InputTrigger
     {
         public MouseButton Button { get; }
 
-        public KeyCounterMouse(MouseButton button)
+        public KeyCounterMouseTrigger(MouseButton button)
             : base(getStringRepresentation(button))
         {
             Button = button;
@@ -39,17 +37,16 @@ namespace osu.Game.Screens.Play
         protected override bool OnMouseDown(MouseDownEvent e)
         {
             if (e.Button == Button)
-            {
+                Activate();
-                IsLit = true;
-                Increment();
-            }
 
             return base.OnMouseDown(e);
         }
 
         protected override void OnMouseUp(MouseUpEvent e)
         {
-            if (e.Button == Button) IsLit = false;
+            if (e.Button == Button)
+                Deactivate();
+
             base.OnMouseUp(e);
         }
     }

osu.Game/Screens/Play/HUDOverlay.cs

@@ -331,7 +331,7 @@ namespace osu.Game.Screens.Play
             ShowHealth = { BindTarget = ShowHealthBar }
         };
 
-        protected KeyCounterDisplay CreateKeyCounter() => new KeyCounterDisplay
+        protected KeyCounterDisplay CreateKeyCounter() => new DefaultKeyCounterDisplay
         {
             Anchor = Anchor.BottomRight,
             Origin = Anchor.BottomRight,

osu.Game/Screens/Play/KeyCounterDisplay.cs

@@ -1,172 +0,0 @@
-// 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.
-
-#nullable disable
-
-using System;
-using System.Linq;
-using osu.Framework.Allocation;
-using osu.Framework.Bindables;
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Framework.Input.Events;
-using osu.Game.Configuration;
-using osuTK;
-using osuTK.Graphics;
-
-namespace osu.Game.Screens.Play
-{
-    public partial class KeyCounterDisplay : Container<KeyCounter>
-    {
-        private const int duration = 100;
-        private const double key_fade_time = 80;
-
-        private readonly Bindable<bool> configVisibility = new Bindable<bool>();
-
-        protected readonly FillFlowContainer<KeyCounter> KeyFlow;
-
-        protected override Container<KeyCounter> Content => KeyFlow;
-
-        /// <summary>
-        /// Whether the key counter should be visible regardless of the configuration value.
-        /// This is true by default, but can be changed.
-        /// </summary>
-        public readonly Bindable<bool> AlwaysVisible = new Bindable<bool>(true);
-
-        public KeyCounterDisplay()
-        {
-            InternalChild = KeyFlow = new FillFlowContainer<KeyCounter>
-            {
-                Direction = FillDirection.Horizontal,
-                AutoSizeAxes = Axes.Both,
-                Alpha = 0,
-            };
-        }
-
-        protected override void Update()
-        {
-            base.Update();
-
-            // Don't use autosize as it will shrink to zero when KeyFlow is hidden.
-            // In turn this can cause the display to be masked off screen and never become visible again.
-            Size = KeyFlow.Size;
-        }
-
-        public override void Add(KeyCounter key)
-        {
-            ArgumentNullException.ThrowIfNull(key);
-
-            base.Add(key);
-            key.IsCounting = IsCounting;
-            key.FadeTime = key_fade_time;
-            key.KeyDownTextColor = KeyDownTextColor;
-            key.KeyUpTextColor = KeyUpTextColor;
-        }
-
-        [BackgroundDependencyLoader]
-        private void load(OsuConfigManager config)
-        {
-            config.BindWith(OsuSetting.KeyOverlay, configVisibility);
-        }
-
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-
-            AlwaysVisible.BindValueChanged(_ => updateVisibility());
-            configVisibility.BindValueChanged(_ => updateVisibility(), true);
-        }
-
-        private bool isCounting = true;
-
-        public bool IsCounting
-        {
-            get => isCounting;
-            set
-            {
-                if (value == isCounting) return;
-
-                isCounting = value;
-                foreach (var child in Children)
-                    child.IsCounting = value;
-            }
-        }
-
-        private Color4 keyDownTextColor = Color4.DarkGray;
-
-        public Color4 KeyDownTextColor
-        {
-            get => keyDownTextColor;
-            set
-            {
-                if (value != keyDownTextColor)
-                {
-                    keyDownTextColor = value;
-                    foreach (var child in Children)
-                        child.KeyDownTextColor = value;
-                }
-            }
-        }
-
-        private Color4 keyUpTextColor = Color4.White;
-
-        public Color4 KeyUpTextColor
-        {
-            get => keyUpTextColor;
-            set
-            {
-                if (value != keyUpTextColor)
-                {
-                    keyUpTextColor = value;
-                    foreach (var child in Children)
-                        child.KeyUpTextColor = value;
-                }
-            }
-        }
-
-        private void updateVisibility() =>
-            // Isolate changing visibility of the key counters from fading this component.
-            KeyFlow.FadeTo(AlwaysVisible.Value || configVisibility.Value ? 1 : 0, duration);
-
-        public override bool HandleNonPositionalInput => receptor == null;
-        public override bool HandlePositionalInput => receptor == null;
-
-        private Receptor receptor;
-
-        public void SetReceptor(Receptor receptor)
-        {
-            if (this.receptor != null)
-                throw new InvalidOperationException("Cannot set a new receptor when one is already active");
-
-            this.receptor = receptor;
-        }
-
-        public partial class Receptor : Drawable
-        {
-            protected readonly KeyCounterDisplay Target;
-
-            public Receptor(KeyCounterDisplay target)
-            {
-                RelativeSizeAxes = Axes.Both;
-                Depth = float.MinValue;
-                Target = target;
-            }
-
-            public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => true;
-
-            protected override bool Handle(UIEvent e)
-            {
-                switch (e)
-                {
-                    case KeyDownEvent:
-                    case KeyUpEvent:
-                    case MouseDownEvent:
-                    case MouseUpEvent:
-                        return Target.Children.Any(c => c.TriggerEvent(e));
-                }
-
-                return base.Handle(e);
-            }
-        }
-    }
-}

osu.Game/Screens/Play/Player.cs

@@ -437,8 +437,11 @@ namespace osu.Game.Screens.Play
                         },
                         KeyCounter =
                         {
+                            IsCounting =
+                            {
+                                Value = false
+                            },
                             AlwaysVisible = { BindTarget = DrawableRuleset.HasReplayLoaded },
-                            IsCounting = false
                         },
                         Anchor = Anchor.Centre,
                         Origin = Anchor.Centre
@@ -478,7 +481,7 @@ namespace osu.Game.Screens.Play
         {
             updateGameplayState();
             updatePauseOnFocusLostState();
-            HUDOverlay.KeyCounter.IsCounting = !isBreakTime.NewValue;
+            HUDOverlay.KeyCounter.IsCounting.Value = !isBreakTime.NewValue;
         }
 
         private void updateGameplayState()