Add Synesthesia mod

osu.Game.Rulesets.Sentakki/Mods/SentakkiModSynesthesia.cs

@@ -0,0 +1,50 @@
+using osu.Game.Beatmaps;
+using osu.Game.Graphics;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Drawables;
+using osu.Game.Rulesets.Sentakki.Objects.Drawables;
+using osu.Game.Screens.Edit;
+using osuTK.Graphics;
+
+namespace osu.Game.Rulesets.Sentakki.Mods;
+
+/// <summary>
+/// Mod that colours <see cref="HitObject"/>s based on the musical division they are on
+/// </summary>
+public class SentakkiModSynesthesia : ModSynesthesia, IApplicableToBeatmap, IApplicableToDrawableHitObject
+{
+    private readonly OsuColour colours = new OsuColour();
+
+    private IBeatmap? currentBeatmap { get; set; }
+
+    public void ApplyToBeatmap(IBeatmap beatmap)
+    {
+        //Store a reference to the current beatmap to look up the beat divisor when notes are drawn
+        if (currentBeatmap != beatmap)
+            currentBeatmap = beatmap;
+    }
+
+    public void ApplyToDrawableHitObject(DrawableHitObject d)
+    {
+        if (currentBeatmap == null) return;
+
+        Color4? timingBasedColour = null;
+
+        d.HitObjectApplied += _ =>
+        {
+            // slider tails are a painful edge case, as their start time is offset 36ms back (see `LastTick`).
+            // to work around this, look up the slider tail's parenting slider's end time instead to ensure proper snap.
+            double snapTime = d.HitObject.StartTime + (d is DrawableSlideBody s ? s.HitObject.ShootDelay : 0);
+            timingBasedColour = BindableBeatDivisor.GetColourFor(currentBeatmap.ControlPointInfo.GetClosestBeatDivisor(snapTime), colours);
+        };
+
+        // Need to set this every update to ensure it doesn't get overwritten by DrawableHitObject.OnApply() -> UpdateComboColour().
+        d.OnUpdate += _ =>
+        {
+            if (timingBasedColour != null)
+                d.AccentColour.Value = timingBasedColour.Value;
+        };
+    }
+}
+

osu.Game.Rulesets.Sentakki/SentakkiRuleset.cs

@@ -114,6 +114,7 @@ public override IEnumerable<Mod> GetModsFor(ModType type)
                         new SentakkiModSpin(),
                         new SentakkiModMuted(),
                         new ModAdaptiveSpeed(),
+                        new SentakkiModSynesthesia()
                     };
 
                 case ModType.System: