From 2ec6aa7fbb92aa286f1281c4043274f6d007e98b Mon Sep 17 00:00:00 2001
From: Dan Balasescu <smoogipoo@smgi.me>
Date: Tue, 26 Dec 2023 12:46:21 +0900
Subject: [PATCH] Make mania scroll speed independent of hit position

---
 .../UI/DrawableManiaRuleset.cs                | 20 ++++++++++++++++++-
 .../Skinning/LegacyManiaSkinConfiguration.cs  |  4 +++-
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/osu.Game.Rulesets.Mania/UI/DrawableManiaRuleset.cs b/osu.Game.Rulesets.Mania/UI/DrawableManiaRuleset.cs
index 9169599798..bea536e4af 100644
--- a/osu.Game.Rulesets.Mania/UI/DrawableManiaRuleset.cs
+++ b/osu.Game.Rulesets.Mania/UI/DrawableManiaRuleset.cs
@@ -19,12 +19,14 @@ using osu.Game.Rulesets.Mania.Beatmaps;
 using osu.Game.Rulesets.Mania.Configuration;
 using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Mania.Replays;
+using osu.Game.Rulesets.Mania.Skinning;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.UI;
 using osu.Game.Rulesets.UI.Scrolling;
 using osu.Game.Scoring;
+using osu.Game.Skinning;
 
 namespace osu.Game.Rulesets.Mania.UI
 {
@@ -57,6 +59,9 @@ namespace osu.Game.Rulesets.Mania.UI
         // Stores the current speed adjustment active in gameplay.
         private readonly Track speedAdjustmentTrack = new TrackVirtual(0);
 
+        [Resolved]
+        private ISkinSource skin { get; set; }
+
         public DrawableManiaRuleset(Ruleset ruleset, IBeatmap beatmap, IReadOnlyList<Mod> mods = null)
             : base(ruleset, beatmap, mods)
         {
@@ -104,7 +109,20 @@ namespace osu.Game.Rulesets.Mania.UI
             updateTimeRange();
         }
 
-        private void updateTimeRange() => TimeRange.Value = smoothTimeRange * speedAdjustmentTrack.AggregateTempo.Value * speedAdjustmentTrack.AggregateFrequency.Value;
+        private void updateTimeRange()
+        {
+            float hitPosition = skin.GetConfig<ManiaSkinConfigurationLookup, float>(
+                                    new ManiaSkinConfigurationLookup(LegacyManiaSkinConfigurationLookups.HitPosition))?.Value
+                                ?? Stage.HIT_TARGET_POSITION;
+
+            const float length_to_default_hit_position = 768 - LegacyManiaSkinConfiguration.DEFAULT_HIT_POSITION;
+            float lengthToHitPosition = 768 - hitPosition;
+
+            // This scaling factor preserves the scroll speed as the scroll length varies from changes to the hit position.
+            float scale = lengthToHitPosition / length_to_default_hit_position;
+
+            TimeRange.Value = smoothTimeRange * speedAdjustmentTrack.AggregateTempo.Value * speedAdjustmentTrack.AggregateFrequency.Value * scale;
+        }
 
         /// <summary>
         /// Computes a scroll time (in milliseconds) from a scroll speed in the range of 1-40.
diff --git a/osu.Game/Skinning/LegacyManiaSkinConfiguration.cs b/osu.Game/Skinning/LegacyManiaSkinConfiguration.cs
index 9acb29a793..042836984a 100644
--- a/osu.Game/Skinning/LegacyManiaSkinConfiguration.cs
+++ b/osu.Game/Skinning/LegacyManiaSkinConfiguration.cs
@@ -21,6 +21,8 @@ namespace osu.Game.Skinning
         /// </summary>
         public const float DEFAULT_COLUMN_SIZE = 30 * POSITION_SCALE_FACTOR;
 
+        public const float DEFAULT_HIT_POSITION = (480 - 402) * POSITION_SCALE_FACTOR;
+
         public readonly int Keys;
 
         public Dictionary<string, Color4> CustomColours { get; } = new Dictionary<string, Color4>();
@@ -35,7 +37,7 @@ namespace osu.Game.Skinning
         public readonly float[] ExplosionWidth;
         public readonly float[] HoldNoteLightWidth;
 
-        public float HitPosition = (480 - 402) * POSITION_SCALE_FACTOR;
+        public float HitPosition = DEFAULT_HIT_POSITION;
         public float LightPosition = (480 - 413) * POSITION_SCALE_FACTOR;
         public float ScorePosition = 300 * POSITION_SCALE_FACTOR;
         public bool ShowJudgementLine = true;