Merge pull request #23520 from jtbiddle/snap-colour-mod

Add "Synesthesia" mod for osu! ruleset

Author: bdach

osu.Game.Rulesets.Osu/Mods/OsuModSynesthesia.cs

@@ -0,0 +1,55 @@
+// Copyright (c) ppy Pty Ltd <[email protected]>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+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.Osu.Objects.Drawables;
+using osu.Game.Screens.Edit;
+using osuTK.Graphics;
+
+namespace osu.Game.Rulesets.Osu.Mods
+{
+    /// <summary>
+    /// Mod that colours <see cref="HitObject"/>s based on the musical division they are on
+    /// </summary>
+    public class OsuModSynesthesia : 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 `LegacyLastTick`).
+                // to work around this, look up the slider tail's parenting slider's end time instead to ensure proper snap.
+                double snapTime = d is DrawableSliderTail tail
+                    ? tail.Slider.GetEndTime()
+                    : d.HitObject.StartTime;
+                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.Osu/OsuRuleset.cs

@@ -204,7 +204,8 @@ public override IEnumerable<Mod> GetModsFor(ModType type)
                         new MultiMod(new OsuModMagnetised(), new OsuModRepel()),
                         new ModAdaptiveSpeed(),
                         new OsuModFreezeFrame(),
-                        new OsuModBubbles()
+                        new OsuModBubbles(),
+                        new OsuModSynesthesia()
                     };
 
                 case ModType.System:

osu.Game/Rulesets/Mods/ModSynesthesia.cs

@@ -0,0 +1,19 @@
+// Copyright (c) ppy Pty Ltd <[email protected]>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Localisation;
+
+namespace osu.Game.Rulesets.Mods
+{
+    /// <summary>
+    /// Mod that colours hitobjects based on the musical division they are on
+    /// </summary>
+    public class ModSynesthesia : Mod
+    {
+        public override string Name => "Synesthesia";
+        public override string Acronym => "SY";
+        public override LocalisableString Description => "Colours hit objects based on the rhythm.";
+        public override double ScoreMultiplier => 1;
+        public override ModType Type => ModType.Fun;
+    }
+}