Add very basic argon mania combo counter implementation

osu.Game.Rulesets.Mania/Skinning/Argon/ArgonManiaComboCounter.cs

@@ -0,0 +1,84 @@
+// 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.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Rulesets.Mania.UI;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Rulesets.UI;
+using osu.Game.Rulesets.UI.Scrolling;
+using osu.Game.Screens.Play.HUD;
+using osu.Game.Skinning;
+using osuTK.Graphics;
+
+namespace osu.Game.Rulesets.Mania.Skinning.Argon
+{
+    public partial class ArgonManiaComboCounter : ComboCounter, ISerialisableDrawable
+    {
+        private OsuSpriteText text = null!;
+
+        protected override double RollingDuration => 500;
+        protected override Easing RollingEasing => Easing.OutQuint;
+
+        private DrawableManiaRuleset maniaRuleset = null!;
+
+        bool ISerialisableDrawable.SupportsClosestAnchor => false;
+
+        [BackgroundDependencyLoader]
+        private void load(DrawableRuleset ruleset, ScoreProcessor scoreProcessor)
+        {
+            maniaRuleset = (DrawableManiaRuleset)ruleset;
+
+            Current.BindTo(scoreProcessor.Combo);
+            Current.BindValueChanged(combo =>
+            {
+                if (combo.OldValue == 0 && combo.NewValue > 0)
+                    text.FadeIn(200, Easing.OutQuint);
+                else if (combo.OldValue > 0 && combo.NewValue == 0)
+                {
+                    if (combo.OldValue > 1)
+                        text.FlashColour(Color4.Red, 2000, Easing.OutQuint);
+
+                    text.FadeOut(200, Easing.InQuint);
+                }
+            });
+
+            UsesFixedAnchor = true;
+        }
+
+        private IBindable<ScrollingDirection> direction = null!;
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            text.Alpha = Current.Value > 0 ? 1 : 0;
+
+            direction = maniaRuleset.ScrollingInfo.Direction.GetBoundCopy();
+            direction.BindValueChanged(_ => updateAnchor());
+
+            // two schedules are required so that updateAnchor is executed in the next frame,
+            // which is when the combo counter receives its Y position by the default layout in ArgonManiaSkinTransformer.
+            Schedule(() => Schedule(updateAnchor));
+        }
+
+        private void updateAnchor()
+        {
+            Anchor &= ~(Anchor.y0 | Anchor.y2);
+            Anchor |= direction.Value == ScrollingDirection.Up ? Anchor.y2 : Anchor.y0;
+
+            // since we flip the vertical anchor when changing scroll direction,
+            // we can use the sign of the Y value as an indicator to make the combo counter displayed correctly.
+            if ((Y < 0 && direction.Value == ScrollingDirection.Down) || (Y > 0 && direction.Value == ScrollingDirection.Up))
+                Y = -Y;
+        }
+
+        protected override IHasText CreateText() => text = new OsuSpriteText
+        {
+            Font = OsuFont.Torus.With(size: 32, fixedWidth: true),
+        };
+    }
+}

osu.Game.Rulesets.Mania/Skinning/Argon/ManiaArgonSkinTransformer.cs

@@ -2,8 +2,11 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Diagnostics;
+using System.Linq;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
+using osu.Framework.Testing;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Mania.Beatmaps;
 using osu.Game.Rulesets.Scoring;
@@ -12,7 +15,7 @@ using osuTK.Graphics;
 
 namespace osu.Game.Rulesets.Mania.Skinning.Argon
 {
-    public class ManiaArgonSkinTransformer : SkinTransformer
+    public class ManiaArgonSkinTransformer : ArgonSkinTransformer
     {
         private readonly ManiaBeatmap beatmap;
 
@@ -26,6 +29,34 @@ namespace osu.Game.Rulesets.Mania.Skinning.Argon
         {
             switch (lookup)
             {
+                case SkinComponentsContainerLookup containerLookup:
+                    switch (containerLookup.Target)
+                    {
+                        case SkinComponentsContainerLookup.TargetArea.MainHUDComponents when containerLookup.Ruleset != null:
+                            Debug.Assert(containerLookup.Ruleset.ShortName == ManiaRuleset.SHORT_NAME);
+
+                            var rulesetHUDComponents = Skin.GetDrawableComponent(lookup);
+
+                            rulesetHUDComponents ??= new DefaultSkinComponentsContainer(container =>
+                            {
+                                var combo = container.ChildrenOfType<ArgonManiaComboCounter>().FirstOrDefault();
+
+                                if (combo != null)
+                                {
+                                    combo.Anchor = Anchor.TopCentre;
+                                    combo.Origin = Anchor.Centre;
+                                    combo.Y = 200;
+                                }
+                            })
+                            {
+                                new ArgonManiaComboCounter(),
+                            };
+
+                            return rulesetHUDComponents;
+                    }
+
+                    break;
+
                 case GameplaySkinComponentLookup<HitResult> resultComponent:
                     // This should eventually be moved to a skin setting, when supported.
                     if (Skin is ArgonProSkin && resultComponent.Component >= HitResult.Great)