Added Mirror Mod for Mania

osu.Game.Rulesets.Mania/ManiaRuleset.cs

@@ -91,6 +91,7 @@ namespace osu.Game.Rulesets.Mania
                         },
                         new ManiaModRandom(),
                         new ManiaModDualStages(),
+                        new ManiaMirrorMod(),
                         new MultiMod
                         {
                             Mods = new Mod[]

osu.Game.Rulesets.Mania/Mods/ManiaMirrorMod.cs

@@ -0,0 +1,28 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Game.Rulesets.Mania.Objects;
+using osu.Game.Rulesets.Mania.UI;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.UI;
+using System.Linq;
+
+namespace osu.Game.Rulesets.Mania.Mods
+{
+    public class ManiaMirrorMod : Mod, IApplicableToRulesetContainer<ManiaHitObject>
+    {
+        public override string Name => "Mirror";
+        public override string ShortenedName => "MR";
+        public override ModType Type => ModType.Special;
+        public override double ScoreMultiplier => 1;
+        public override bool Ranked => true;
+
+        public void ApplyToRulesetContainer(RulesetContainer<ManiaHitObject> rulesetContainer)
+        {
+            var availableColumns = ((ManiaRulesetContainer)rulesetContainer).Beatmap.TotalColumns;
+
+            rulesetContainer.Objects.OfType<ManiaHitObject>().ForEach(h => h.Column = -(h.Column) + (availableColumns)-1);
+        }
+    }
+}

osu.Game.Rulesets.Mania/osu.Game.Rulesets.Mania.csproj

@@ -81,6 +81,7 @@
     <Compile Include="Judgements\ManiaJudgement.cs" />
     <Compile Include="ManiaDifficultyCalculator.cs" />
     <Compile Include="Mods\IPlayfieldTypeMod.cs" />
+    <Compile Include="Mods\ManiaMirrorMod.cs" />
     <Compile Include="Mods\ManiaKeyMod.cs" />
     <Compile Include="Mods\ManiaModAutoplay.cs" />
     <Compile Include="Mods\ManiaModDaycore.cs" />