Refactor OsuModBarrelRoll to allow it's usage by other rulesets

osu.Game/Rulesets/Mods/ModBarrelRoll.cs

@@ -0,0 +1,52 @@
+// 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.Framework.Extensions;
+using osu.Framework.Graphics;
+using osu.Game.Configuration;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.UI;
+using osuTK;
+
+namespace osu.Game.Rulesets.Mods
+{
+    public abstract class ModBarrelRoll<TObject> : Mod, IUpdatableByPlayfield, IApplicableToDrawableRuleset<TObject>
+        where TObject : HitObject
+    {
+        protected float CurrentRotation { get; private set; }
+
+        [SettingSource("Roll speed", "Rotations per minute")]
+        public BindableNumber<double> SpinSpeed { get; } = new BindableDouble(0.5)
+        {
+            MinValue = 0.02,
+            MaxValue = 12,
+            Precision = 0.01,
+        };
+
+        [SettingSource("Direction", "The direction of rotation")]
+        public Bindable<RotationDirection> Direction { get; } = new Bindable<RotationDirection>(RotationDirection.Clockwise);
+
+        public override string Name => "Barrel Roll";
+        public override string Acronym => "BR";
+        public override string Description => "The whole playfield is on a wheel!";
+        public override double ScoreMultiplier => 1;
+
+        public override string SettingDescription => $"{SpinSpeed.Value} rpm {Direction.Value.GetDescription().ToLowerInvariant()}";
+
+        /// <summary>
+        /// Used to allow all hitobjects to stay within the visible region.
+        /// </summary>
+        protected abstract Vector2 PlayfieldScale { get; }
+
+        public void Update(Playfield playfield)
+        {
+            playfield.Rotation = CurrentRotation = (Direction.Value == RotationDirection.Counterclockwise ? -1 : 1) * 360 * (float)(playfield.Time.Current / 60000 * SpinSpeed.Value);
+        }
+
+        public void ApplyToDrawableRuleset(DrawableRuleset<TObject> drawableRuleset)
+        {
+            drawableRuleset.Playfield.Scale = PlayfieldScale;
+        }
+    }
+}