Add "retro" default skin

osu.Game.Rulesets.Mania/ManiaRuleset.cs

@@ -79,6 +79,7 @@ public class ManiaRuleset : Ruleset, ILegacyRuleset
                     return new ManiaArgonSkinTransformer(skin, beatmap);
 
                 case DefaultLegacySkin:
+                case RetroSkin:
                     return new ManiaClassicSkinTransformer(skin, beatmap);
 
                 case LegacySkin:

osu.Game/Overlays/Settings/Sections/SkinSection.cs

@@ -130,6 +130,7 @@ private void skinsChanged(IRealmCollection<SkinInfo> sender, ChangeSet changes)
             dropdownItems.Add(sender.Single(s => s.ID == SkinInfo.ARGON_PRO_SKIN).ToLive(realm));
             dropdownItems.Add(sender.Single(s => s.ID == SkinInfo.TRIANGLES_SKIN).ToLive(realm));
             dropdownItems.Add(sender.Single(s => s.ID == SkinInfo.CLASSIC_SKIN).ToLive(realm));
+            dropdownItems.Add(sender.Single(s => s.ID == SkinInfo.RETRO_SKIN).ToLive(realm));
 
             dropdownItems.Add(random_skin_info);
 

osu.Game/Screens/Backgrounds/BackgroundScreenDefault.cs

@@ -163,6 +163,7 @@ private Background createBackground()
                             case TrianglesSkin:
                             case ArgonSkin:
                             case DefaultLegacySkin:
+                            case RetroSkin:
                                 // default skins should use the default background rotation, which won't be the case if a SkinBackground is created for them.
                                 break;
 

osu.Game/Skinning/RetroSkin.cs

@@ -0,0 +1,58 @@
+// 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 System;
+using JetBrains.Annotations;
+using osu.Framework.Graphics.Textures;
+using osu.Framework.IO.Stores;
+using osu.Game.Extensions;
+using osu.Game.IO;
+
+namespace osu.Game.Skinning
+{
+    /// <summary>
+    /// A skin that looks like osu!stable as it was around 2008.
+    /// </summary>
+    /// <remarks>
+    /// "Around 2008" was chosen as the cutoff for this skin because that's when the look of core gameplay settled into its final design (until <see cref="DefaultLegacySkin"/>). Skin elements from later versions of osu! were preferred as long as they only fixed bugs or applied minor tweaks to 2008 elements.
+    /// </remarks>
+    public class RetroSkin : LegacySkin
+    {
+        public static SkinInfo CreateInfo() => new SkinInfo
+        {
+            ID = Skinning.SkinInfo.RETRO_SKIN,
+            Name = "osu! \"retro\" (2008)",
+            Creator = "team osu!",
+            Protected = true,
+            InstantiationInfo = typeof(RetroSkin).GetInvariantInstantiationInfo(),
+        };
+
+        public RetroSkin(IStorageResourceProvider resources)
+            : this(CreateInfo(), resources)
+        {
+        }
+
+        [UsedImplicitly(ImplicitUseKindFlags.InstantiatedWithFixedConstructorSignature)]
+        public RetroSkin(SkinInfo skin, IStorageResourceProvider resources)
+            : base(
+                skin,
+                resources,
+                new NamespacedResourceStore<byte[]>(resources.Resources, "Skins/Retro")
+            )
+        {
+        }
+
+        public override Texture? GetTexture(string componentName, WrapMode wrapModeS, WrapMode wrapModeT)
+        {
+            // Retro taiko hit explosions use osu textures
+            if (componentName.StartsWith("taiko-hit", StringComparison.Ordinal))
+                componentName = componentName.Substring(6);
+
+            // Retro taiko slider has no fail variant, but it needs to exist to avoid displaying nothing
+            if (componentName == "taiko-slider-fail")
+                componentName = "taiko-slider";
+
+            return base.GetTexture(componentName, wrapModeS, wrapModeT);
+        }
+    }
+}

osu.Game/Skinning/SkinInfo.cs

@@ -20,6 +20,7 @@ public class SkinInfo : RealmObject, IHasRealmFiles, IEquatable<SkinInfo>, IHasG
         internal static readonly Guid ARGON_SKIN = new Guid("CFFA69DE-B3E3-4DEE-8563-3C4F425C05D0");
         internal static readonly Guid ARGON_PRO_SKIN = new Guid("9FC9CF5D-0F16-4C71-8256-98868321AC43");
         internal static readonly Guid CLASSIC_SKIN = new Guid("81F02CD3-EEC6-4865-AC23-FAE26A386187");
+        internal static readonly Guid RETRO_SKIN = new Guid("0555C76A-CC6B-4BB4-9548-DF76BA72EF25");
         internal static readonly Guid RANDOM_SKIN = new Guid("D39DFEFB-477C-4372-B1EA-2BCEA5FB8908");
 
         [PrimaryKey]

osu.Game/Skinning/SkinManager.cs

@@ -64,6 +64,8 @@ public class SkinManager : ModelManager<SkinInfo>, ISkinSource, IStorageResource
 
         private Skin trianglesSkin { get; }
 
+        private Skin retroSkin { get; }
+
         public override bool PauseImports
         {
             get => base.PauseImports;
@@ -91,6 +93,7 @@ public SkinManager(Storage storage, RealmAccess realm, GameHost host, IResourceS
 
             var defaultSkins = new[]
             {
+                retroSkin = new RetroSkin(this),
                 DefaultClassicSkin = new DefaultLegacySkin(this),
                 trianglesSkin = new TrianglesSkin(this),
                 argonSkin = new ArgonSkin(this),
@@ -369,6 +372,9 @@ public void SetSkinFromConfiguration(string guidString)
             {
                 if (guid == SkinInfo.CLASSIC_SKIN)
                     skinInfo = DefaultClassicSkin.SkinInfo;
+
+                if (guid == SkinInfo.RETRO_SKIN)
+                    skinInfo = retroSkin.SkinInfo;
             }
 
             CurrentSkinInfo.Value = skinInfo ?? trianglesSkin.SkinInfo;

osu.Game/Skinning/SkinnableSprite.cs

@@ -122,6 +122,7 @@ static bool isUserSkin(ISkin skin)
                        || skin.GetType() == typeof(ArgonProSkin)
                        || skin.GetType() == typeof(ArgonSkin)
                        || skin.GetType() == typeof(DefaultLegacySkin)
+                       || skin.GetType() == typeof(RetroSkin)
                        || skin.GetType() == typeof(LegacySkin);
             }
         }

osu.Game/Tests/Visual/SkinnableTestScene.cs

@@ -34,7 +34,7 @@ public abstract partial class SkinnableTestScene : OsuGridTestScene, IStorageRes
         private Skin legacySkin;
         private Skin argonSkin;
         private Skin specialSkin;
-        private Skin oldSkin;
+        private Skin retroSkin;
 
         [Resolved]
         private GameHost host { get; set; }
@@ -54,7 +54,7 @@ private void load()
             metricsSkin = new TestLegacySkin(new SkinInfo { Name = "metrics-skin" }, new NamespacedResourceStore<byte[]>(dllStore, "Resources/metrics_skin"), this, true);
             legacySkin = new DefaultLegacySkin(this);
             specialSkin = new TestLegacySkin(new SkinInfo { Name = "special-skin" }, new NamespacedResourceStore<byte[]>(dllStore, "Resources/special_skin"), this, true);
-            oldSkin = new TestLegacySkin(new SkinInfo { Name = "old-skin" }, new NamespacedResourceStore<byte[]>(dllStore, "Resources/old_skin"), this, true);
+            retroSkin = new RetroSkin(this);
         }
 
         private readonly List<Drawable> createdDrawables = new List<Drawable>();
@@ -70,7 +70,7 @@ protected void SetContents(Func<ISkin, Drawable> creationFunction)
             Cell(2).Child = createProvider(metricsSkin, creationFunction, beatmap);
             Cell(3).Child = createProvider(legacySkin, creationFunction, beatmap);
             Cell(4).Child = createProvider(specialSkin, creationFunction, beatmap);
-            Cell(5).Child = createProvider(oldSkin, creationFunction, beatmap);
+            Cell(5).Child = createProvider(retroSkin, creationFunction, beatmap);
         }
 
         protected IEnumerable<Drawable> CreatedDrawables => createdDrawables;