List incompatible mods in tooltip of mod button

osu.Game/Overlays/Mods/ModButton.cs

@@ -23,7 +23,7 @@ namespace osu.Game.Overlays.Mods
     /// <summary>
     /// Represents a clickable button which can cycle through one of more mods.
     /// </summary>
-    public class ModButton : ModButtonEmpty, IHasTooltip
+    public class ModButton : ModButtonEmpty, IHasCustomTooltip
     {
         private ModIcon foregroundIcon;
         private ModIcon backgroundIcon;
@@ -308,5 +308,9 @@ public ModButton(Mod mod)
 
             Mod = mod;
         }
+
+        public ITooltip GetCustomTooltip() => new ModButtonTooltip();
+
+        public object TooltipContent => SelectedMod ?? Mods[0];
     }
 }

osu.Game/Overlays/Mods/ModButtonTooltip.cs

@@ -0,0 +1,145 @@
+// 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 System.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Cursor;
+using osu.Framework.Graphics.Shapes;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Rulesets;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.UI;
+using osu.Game.Screens.Play.HUD;
+using osuTK;
+
+namespace osu.Game.Overlays.Mods
+{
+    public class ModButtonTooltip : VisibilityContainer, ITooltip
+    {
+        private readonly OsuSpriteText descriptionText;
+        private readonly Box background;
+        private readonly OsuSpriteText incompatibleText;
+
+        private readonly Bindable<IReadOnlyList<Mod>> incompatibleMods = new Bindable<IReadOnlyList<Mod>>();
+
+        [Resolved]
+        private Bindable<RulesetInfo> ruleset { get; set; }
+
+        public ModButtonTooltip()
+        {
+            AutoSizeAxes = Axes.Both;
+            Masking = true;
+            CornerRadius = 5;
+
+            Children = new Drawable[]
+            {
+                background = new Box
+                {
+                    RelativeSizeAxes = Axes.Both
+                },
+                new FillFlowContainer
+                {
+                    AutoSizeAxes = Axes.Both,
+                    Direction = FillDirection.Vertical,
+                    Padding = new MarginPadding { Left = 10, Right = 10, Top = 5, Bottom = 5 },
+                    Children = new Drawable[]
+                    {
+                        descriptionText = new OsuSpriteText
+                        {
+                            Font = OsuFont.GetFont(weight: FontWeight.Regular),
+                            Margin = new MarginPadding { Bottom = 5 }
+                        },
+                        incompatibleText = new OsuSpriteText
+                        {
+                            Font = OsuFont.GetFont(weight: FontWeight.Regular),
+                            Text = "Incompatible with:"
+                        },
+                        new ModDisplay
+                        {
+                            Current = incompatibleMods,
+                            ExpansionMode = ExpansionMode.AlwaysExpanded,
+                            Scale = new Vector2(0.7f)
+                        }
+                    }
+                },
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            background.Colour = colours.Gray3;
+            descriptionText.Colour = colours.BlueLighter;
+            incompatibleText.Colour = colours.BlueLight;
+        }
+
+        protected override void PopIn() => this.FadeIn(200, Easing.OutQuint);
+        protected override void PopOut() => this.FadeOut(200, Easing.OutQuint);
+
+        private Drawable getModItem(Mod mod)
+        {
+            return new FillFlowContainer
+            {
+                Anchor = Anchor.CentreLeft,
+                Origin = Anchor.CentreLeft,
+                AutoSizeAxes = Axes.Both,
+                Direction = FillDirection.Horizontal,
+                Children = new Drawable[]
+                {
+                    new ModIcon(mod, false)
+                    {
+                        Anchor = Anchor.CentreLeft,
+                        Origin = Anchor.CentreLeft,
+                        AutoSizeAxes = Axes.Both,
+                        Scale = new Vector2(0.4f)
+                    },
+                    new OsuSpriteText
+                    {
+                        Anchor = Anchor.CentreLeft,
+                        Origin = Anchor.CentreLeft,
+                        Margin = new MarginPadding { Left = 5 },
+                        Font = OsuFont.GetFont(weight: FontWeight.Regular),
+                        Text = mod.Name,
+                    },
+                }
+            };
+        }
+
+        private string lastMod;
+
+        public bool SetContent(object content)
+        {
+            if (!(content is Mod mod))
+                return false;
+
+            if (mod.Acronym == lastMod) return true;
+
+            lastMod = mod.Acronym;
+
+            descriptionText.Text = mod.Description;
+
+            var incompatibleTypes = mod.IncompatibleMods;
+
+            var allMods = ruleset.Value.CreateInstance().GetAllMods();
+
+            incompatibleMods.Value = allMods.Where(m => incompatibleTypes.Any(t => t.IsInstanceOfType(m))).ToList();
+
+            if (!incompatibleMods.Value.Any())
+            {
+                incompatibleText.Text = "Compatible with all mods";
+                return true;
+            }
+
+            incompatibleText.Text = "Incompatible with:";
+
+            return true;
+        }
+
+        public void Move(Vector2 pos) => Position = pos;
+    }
+}