Adjust mania hit windows with gameplay rate

osu.Game.Rulesets.Mania/Mods/IManiaRateAdjustmentMod.cs

@@ -0,0 +1,47 @@
+// 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.Game.Beatmaps;
+using osu.Game.Rulesets.Mania.Objects;
+using osu.Game.Rulesets.Mania.Scoring;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Scoring;
+
+namespace osu.Game.Rulesets.Mania.Mods
+{
+    /// <summary>
+    /// May be attached to rate-adjustment mods to adjust hit windows adjust relative to gameplay rate.
+    /// </summary>
+    /// <remarks>
+    /// Historically, in osu!mania, hit windows are expected to adjust relative to the gameplay rate such that the real-world hit window remains the same.
+    /// </remarks>
+    public interface IManiaRateAdjustmentMod : IApplicableToDifficulty, IApplicableToHitObject
+    {
+        BindableNumber<double> SpeedChange { get; }
+
+        HitWindows HitWindows { get; set; }
+
+        void IApplicableToDifficulty.ApplyToDifficulty(BeatmapDifficulty difficulty)
+        {
+            HitWindows = new ManiaHitWindows(SpeedChange.Value);
+            HitWindows.SetDifficulty(difficulty.OverallDifficulty);
+        }
+
+        void IApplicableToHitObject.ApplyToHitObject(HitObject hitObject)
+        {
+            switch (hitObject)
+            {
+                case Note:
+                    hitObject.HitWindows = HitWindows;
+                    break;
+
+                case HoldNote hold:
+                    hold.Head.HitWindows = HitWindows;
+                    hold.Tail.HitWindows = HitWindows;
+                    break;
+            }
+        }
+    }
+}

osu.Game.Rulesets.Mania/Mods/ManiaModDaycore.cs

@@ -1,11 +1,14 @@
 // 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.Game.Rulesets.Mania.Scoring;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
 
 namespace osu.Game.Rulesets.Mania.Mods
 {
-    public class ManiaModDaycore : ModDaycore
+    public class ManiaModDaycore : ModDaycore, IManiaRateAdjustmentMod
     {
+        public HitWindows HitWindows { get; set; } = new ManiaHitWindows();
     }
 }

osu.Game.Rulesets.Mania/Mods/ManiaModDoubleTime.cs

@@ -1,11 +1,14 @@
 // 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.Game.Rulesets.Mania.Scoring;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
 
 namespace osu.Game.Rulesets.Mania.Mods
 {
-    public class ManiaModDoubleTime : ModDoubleTime
+    public class ManiaModDoubleTime : ModDoubleTime, IManiaRateAdjustmentMod
     {
+        public HitWindows HitWindows { get; set; } = new ManiaHitWindows();
     }
 }

osu.Game.Rulesets.Mania/Mods/ManiaModHalfTime.cs

@@ -1,11 +1,14 @@
 // 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.Game.Rulesets.Mania.Scoring;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
 
 namespace osu.Game.Rulesets.Mania.Mods
 {
-    public class ManiaModHalfTime : ModHalfTime
+    public class ManiaModHalfTime : ModHalfTime, IManiaRateAdjustmentMod
     {
+        public HitWindows HitWindows { get; set; } = new ManiaHitWindows();
     }
 }

osu.Game.Rulesets.Mania/Mods/ManiaModNightcore.cs

@@ -2,11 +2,14 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Game.Rulesets.Mania.Objects;
+using osu.Game.Rulesets.Mania.Scoring;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
 
 namespace osu.Game.Rulesets.Mania.Mods
 {
-    public class ManiaModNightcore : ModNightcore<ManiaHitObject>
+    public class ManiaModNightcore : ModNightcore<ManiaHitObject>, IManiaRateAdjustmentMod
     {
+        public HitWindows HitWindows { get; set; } = new ManiaHitWindows();
     }
 }

osu.Game.Rulesets.Mania/Scoring/ManiaHitWindows.cs

@@ -1,12 +1,25 @@
 // 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.Linq;
 using osu.Game.Rulesets.Scoring;
 
 namespace osu.Game.Rulesets.Mania.Scoring
 {
     public class ManiaHitWindows : HitWindows
     {
+        private readonly double multiplier;
+
+        public ManiaHitWindows()
+            : this(1)
+        {
+        }
+
+        public ManiaHitWindows(double multiplier)
+        {
+            this.multiplier = multiplier;
+        }
+
         public override bool IsHitResultAllowed(HitResult result)
         {
             switch (result)
@@ -22,5 +35,12 @@ namespace osu.Game.Rulesets.Mania.Scoring
 
             return false;
         }
+
+        protected override DifficultyRange[] GetRanges() => base.GetRanges().Select(r =>
+            new DifficultyRange(
+                r.Result,
+                r.Min * multiplier,
+                r.Average * multiplier,
+                r.Max * multiplier)).ToArray();
     }
 }