Add "ghost" mod for osu

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

@@ -0,0 +1,67 @@
+// 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.UI;
+using osu.Game.Rulesets.Mods;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Bindables;
+using osu.Framework.Localisation;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Configuration;
+using osu.Game.Overlays.Settings;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Scoring;
+
+namespace osu.Game.Rulesets.Osu.Mods
+{
+    public class OsuModGhost : Mod, IUpdatableByPlayfield, IApplicableToScoreProcessor
+    {
+        public override string Name => "Ghost";
+        public override string Acronym => "G";
+        public override ModType Type => ModType.Fun;
+        public override IconUsage? Icon => FontAwesome.Solid.Ghost;
+        public override string Description => "Where's the cursor?";
+        public override double ScoreMultiplier => 1;
+        
+        private readonly BindableNumber<float> ghostAlpha = new BindableFloat(0);
+        private BindableNumber<int> currentCombo;
+
+        [SettingSource(
+            "Hidden at combo",
+            "The combo count at which the cursor becomes completely hidden",
+            SettingControlType = typeof(SettingsSlider<int, HiddenComboSlider>)
+        )]
+        public BindableInt HiddenComboCount { get; } = new BindableInt
+        {
+            Default = 10,
+            Value = 10,
+            MinValue = 0,
+            MaxValue = 50,
+        };
+
+        public ScoreRank AdjustRank(ScoreRank rank, double accuracy) => rank;
+        public void ApplyToScoreProcessor(ScoreProcessor scoreProcessor)
+        {
+            currentCombo = scoreProcessor.Combo.GetBoundCopy();
+            currentCombo.BindValueChanged(combo =>
+            {
+                float dimFactor = HiddenComboCount.Value == 0 ? 1 : (float)combo.NewValue / HiddenComboCount.Value;
+
+                scoreProcessor.TransformBindableTo(ghostAlpha, 1-dimFactor, 100, Easing.OutQuint);
+            }, true);
+        }
+
+
+        public virtual void Update(Playfield playfield)
+        {
+            playfield.Cursor.Alpha = ghostAlpha.Value;
+        }
+        
+    }
+
+    public class HiddenComboSlider : OsuSliderBar<int>
+    {
+        public override LocalisableString TooltipText => Current.Value == 0 ? "always hidden" : base.TooltipText;
+    }
+}

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -192,6 +192,7 @@ namespace osu.Game.Rulesets.Osu
                         new OsuModBarrelRoll(),
                         new OsuModApproachDifferent(),
                         new OsuModMuted(),
+                        new OsuModGhost(),
                     };
 
                 case ModType.System: