Add "Barrel Roll" mod

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

@@ -0,0 +1,30 @@
+// 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.Game.Configuration;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.UI;
+
+namespace osu.Game.Rulesets.Osu.Mods
+{
+    public class OsuModBarrelRoll : Mod, IUpdatableByPlayfield
+    {
+        [SettingSource("Roll speed", "Speed at which things rotate")]
+        public BindableNumber<double> SpinSpeed { get; } = new BindableDouble(1)
+        {
+            MinValue = 0.1,
+            MaxValue = 20,
+            Precision = 0.1,
+        };
+
+        public override string Name => "Barrel Roll";
+        public override string Acronym => "BR";
+        public override double ScoreMultiplier => 1;
+
+        public void Update(Playfield playfield)
+        {
+            playfield.Rotation = (float)(playfield.Time.Current / 1000 * SpinSpeed.Value);
+        }
+    }
+}

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -185,6 +185,7 @@ public override IEnumerable<Mod> GetModsFor(ModType type)
                         new MultiMod(new OsuModGrow(), new OsuModDeflate()),
                         new MultiMod(new ModWindUp(), new ModWindDown()),
                         new OsuModTraceable(),
+                        new OsuModBarrelRoll(),
                     };
 
                 case ModType.System:

osu.Game.Rulesets.Osu/UI/OsuPlayfield.cs

@@ -42,6 +42,9 @@ public class OsuPlayfield : Playfield
 
         public OsuPlayfield()
         {
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
             InternalChildren = new Drawable[]
             {
                 playfieldBorder = new PlayfieldBorder { RelativeSizeAxes = Axes.Both },