Merge pull request #5969 from peppy/skin-configuration-refactor

Refactor skin configuration lookups to be more flexible

Co-authored-by: Dan Balasescu <smoogipoo@smgi.me>

osu.Game.Rulesets.Catch.Tests/TestSceneCatcher.cs

@@ -14,6 +14,7 @@ using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.Sprites;
 using osuTK.Graphics;
 using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics.Textures;
 using osu.Game.Audio;
 
@@ -99,8 +100,7 @@ namespace osu.Game.Rulesets.Catch.Tests
             public Texture GetTexture(string componentName) =>
                 throw new NotImplementedException();
 
-            public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration =>
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => throw new NotImplementedException();
-                throw new NotImplementedException();
         }
     }
 }

osu.Game.Rulesets.Osu.Tests/TestSceneSkinFallbacks.cs

@@ -7,6 +7,7 @@ using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Graphics.Textures;
@@ -135,6 +136,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             public SampleChannel GetSample(ISampleInfo sampleInfo) => null;
 
             public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration => default;
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => null;
 
             public event Action SourceChanged;
 

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs

@@ -12,6 +12,7 @@ using osu.Framework.Bindables;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Osu.Configuration;
+using osu.Game.Rulesets.Osu.Skinning;
 using osu.Game.Rulesets.Scoring;
 using osuTK.Graphics;
 using osu.Game.Skinning;
@@ -166,12 +167,12 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         {
             base.SkinChanged(skin, allowFallback);
 
-            Body.BorderSize = skin.GetValue<SkinConfiguration, float?>(s => s.SliderBorderSize) ?? SliderBody.DEFAULT_BORDER_SIZE;
+            Body.BorderSize = skin.GetConfig<OsuSkinConfiguration, float>(OsuSkinConfiguration.SliderBorderSize)?.Value ?? SliderBody.DEFAULT_BORDER_SIZE;
-            sliderPathRadius = skin.GetValue<SkinConfiguration, float?>(s => s.SliderPathRadius) ?? OsuHitObject.OBJECT_RADIUS;
+            sliderPathRadius = skin.GetConfig<OsuSkinConfiguration, float>(OsuSkinConfiguration.SliderPathRadius)?.Value ?? OsuHitObject.OBJECT_RADIUS;
             updatePathRadius();
 
-            Body.AccentColour = skin.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.ContainsKey("SliderTrackOverride") ? s.CustomColours["SliderTrackOverride"] : (Color4?)null) ?? AccentColour.Value;
+            Body.AccentColour = skin.GetConfig<OsuSkinColour, Color4>(OsuSkinColour.SliderTrackOverride)?.Value ?? AccentColour.Value;
-            Body.BorderColour = skin.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.ContainsKey("SliderBorder") ? s.CustomColours["SliderBorder"] : (Color4?)null) ?? Color4.White;
+            Body.BorderColour = skin.GetConfig<OsuSkinColour, Color4>(OsuSkinColour.SliderBorder)?.Value ?? Color4.White;
         }
 
         private void updatePathRadius() => Body.PathRadius = slider.Scale * sliderPathRadius;

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBall.cs

@@ -11,6 +11,7 @@ using osu.Framework.Input;
 using osu.Framework.Input.Events;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.Objects.Types;
+using osu.Game.Rulesets.Osu.Skinning;
 using osuTK.Graphics;
 using osu.Game.Skinning;
 using osuTK;
@@ -218,7 +219,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
             {
                 RelativeSizeAxes = Axes.Both;
 
-                float radius = skin.GetValue<SkinConfiguration, float?>(s => s.SliderPathRadius) ?? OsuHitObject.OBJECT_RADIUS;
+                float radius = skin.GetConfig<OsuSkinConfiguration, float>(OsuSkinConfiguration.SliderPathRadius)?.Value ?? OsuHitObject.OBJECT_RADIUS;
 
                 InternalChild = new CircularContainer
                 {

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -167,7 +167,7 @@ namespace osu.Game.Rulesets.Osu
 
         public override RulesetSettingsSubsection CreateSettings() => new OsuSettingsSubsection(this);
 
-        public override ISkin CreateLegacySkinProvider(ISkinSource source) => new OsuLegacySkin(source);
+        public override ISkin CreateLegacySkinProvider(ISkinSource source) => new OsuLegacySkinTransformer(source);
 
         public override int? LegacyID => 0;
 

osu.Game.Rulesets.Osu/Skinning/LegacySliderBall.cs

@@ -23,7 +23,7 @@ namespace osu.Game.Rulesets.Osu.Skinning
         [BackgroundDependencyLoader]
         private void load(ISkinSource skin, DrawableHitObject drawableObject)
         {
-            animationContent.Colour = skin.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.ContainsKey("SliderBall") ? s.CustomColours["SliderBall"] : (Color4?)null) ?? Color4.White;
+            animationContent.Colour = skin.GetConfig<OsuSkinColour, Color4>(OsuSkinColour.SliderBall)?.Value ?? Color4.White;
 
             InternalChildren = new[]
             {

osu.Game.Rulesets.Osu/Skinning/OsuLegacySkinTransformer.cs

@@ -3,21 +3,19 @@
 
 using System;
 using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Textures;
 using osu.Game.Audio;
 using osu.Game.Skinning;
 using osuTK;
-using osuTK.Graphics;
 
 namespace osu.Game.Rulesets.Osu.Skinning
 {
-    public class OsuLegacySkin : ISkin
+    public class OsuLegacySkinTransformer : ISkin
     {
         private readonly ISkin source;
 
-        private Lazy<SkinConfiguration> configuration;
-
         private Lazy<bool> hasHitCircle;
 
         /// <summary>
@@ -27,7 +25,7 @@ namespace osu.Game.Rulesets.Osu.Skinning
         /// </summary>
         private const float legacy_circle_radius = 64 - 5;
 
-        public OsuLegacySkin(ISkinSource source)
+        public OsuLegacySkinTransformer(ISkinSource source)
         {
             this.source = source;
 
@@ -37,21 +35,6 @@ namespace osu.Game.Rulesets.Osu.Skinning
 
         private void sourceChanged()
         {
-            // these need to be lazy in order to ensure they aren't called before the dependencies have been loaded into our source.
-            configuration = new Lazy<SkinConfiguration>(() =>
-            {
-                var config = new SkinConfiguration();
-                if (hasHitCircle.Value)
-                    config.SliderPathRadius = legacy_circle_radius;
-
-                // defaults should only be applied for non-beatmap skins (which are parsed via this constructor).
-                config.CustomColours["SliderBall"] =
-                    source.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.TryGetValue("SliderBall", out var val) ? val : (Color4?)null)
-                    ?? new Color4(2, 170, 255, 255);
-
-                return config;
-            });
-
             hasHitCircle = new Lazy<bool>(() => source.GetTexture("hitcircle") != null);
         }
 
@@ -96,8 +79,8 @@ namespace osu.Game.Rulesets.Osu.Skinning
                     return null;
 
                 case OsuSkinComponents.HitCircleText:
-                    string font = GetValue<SkinConfiguration, string>(config => config.HitCircleFont);
+                    var font = GetConfig<OsuSkinConfiguration, string>(OsuSkinConfiguration.HitCircleFont)?.Value ?? "default";
-                    var overlap = GetValue<SkinConfiguration, float>(config => config.HitCircleOverlap);
+                    var overlap = GetConfig<OsuSkinConfiguration, float>(OsuSkinConfiguration.HitCircleOverlap)?.Value ?? 0;
 
                     return !hasFont(font)
                         ? null
@@ -116,13 +99,27 @@ namespace osu.Game.Rulesets.Osu.Skinning
 
         public SampleChannel GetSample(ISampleInfo sample) => source.GetSample(sample);
 
-        public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration
+        public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup)
         {
-            TValue val;
+            switch (lookup)
-            if (configuration.Value is TConfiguration conf && (val = query.Invoke(conf)) != null)
+            {
-                return val;
+                case OsuSkinColour colour:
+                    return source.GetConfig<SkinCustomColourLookup, TValue>(new SkinCustomColourLookup(colour));
 
-            return source.GetValue(query);
+                case OsuSkinConfiguration osuLookup:
+                    switch (osuLookup)
+                    {
+                        case OsuSkinConfiguration.SliderPathRadius:
+                            if (hasHitCircle.Value)
+                                return SkinUtils.As<TValue>(new BindableFloat(legacy_circle_radius));
+
+                            break;
+                    }
+
+                    break;
+            }
+
+            return source.GetConfig<TLookup, TValue>(lookup);
         }
 
         private bool hasFont(string fontName) => source.GetTexture($"{fontName}-0") != null;

osu.Game.Rulesets.Osu/Skinning/OsuSkinColour.cs

@@ -0,0 +1,12 @@
+// 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.
+
+namespace osu.Game.Rulesets.Osu.Skinning
+{
+    public enum OsuSkinColour
+    {
+        SliderTrackOverride,
+        SliderBorder,
+        SliderBall
+    }
+}

osu.Game.Rulesets.Osu/Skinning/OsuSkinConfiguration.cs

@@ -0,0 +1,14 @@
+// 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.
+
+namespace osu.Game.Rulesets.Osu.Skinning
+{
+    public enum OsuSkinConfiguration
+    {
+        HitCircleFont,
+        HitCircleOverlap,
+        SliderBorderSize,
+        SliderPathRadius,
+        CursorExpand,
+    }
+}

osu.Game.Rulesets.Osu/UI/Cursor/OsuCursor.cs

@@ -10,6 +10,7 @@ using osu.Framework.Graphics.Effects;
 using osu.Framework.Graphics.Shapes;
 using osu.Game.Beatmaps;
 using osu.Game.Configuration;
+using osu.Game.Rulesets.Osu.Skinning;
 using osu.Game.Skinning;
 using osuTK;
 using osuTK.Graphics;
@@ -38,7 +39,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
         protected override void SkinChanged(ISkinSource skin, bool allowFallback)
         {
-            cursorExpand = skin.GetValue<SkinConfiguration, bool>(s => s.CursorExpand ?? true);
+            cursorExpand = skin.GetConfig<OsuSkinConfiguration, bool>(OsuSkinConfiguration.CursorExpand)?.Value ?? true;
         }
 
         [BackgroundDependencyLoader]

osu.Game.Tests/Resources/skin.ini

@@ -1,5 +1,6 @@
 [General]
 Name: test skin
+TestLookup: TestValue
 
 [Colours]
 Combo1 : 142,199,255

osu.Game.Tests/Skins/LegacySkinDecoderTest.cs

@@ -41,5 +41,20 @@ namespace osu.Game.Tests.Skins
                     Assert.AreEqual(expectedColors[i], comboColors[i]);
             }
         }
+
+        [Test]
+        public void TestDecodeGeneral()
+        {
+            var decoder = new LegacySkinDecoder();
+
+            using (var resStream = TestResources.OpenResource("skin.ini"))
+            using (var stream = new StreamReader(resStream))
+            {
+                var config = decoder.Decode(stream);
+
+                Assert.AreEqual("test skin", config.SkinInfo.Name);
+                Assert.AreEqual("TestValue", config.ConfigDictionary["TestLookup"]);
+            }
+        }
     }
 }

osu.Game.Tests/Skins/TestSceneSkinConfigurationLookup.cs

@@ -0,0 +1,156 @@
+// 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.Collections.Generic;
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Textures;
+using osu.Game.Audio;
+using osu.Game.Skinning;
+using osu.Game.Tests.Visual;
+using osuTK.Graphics;
+
+namespace osu.Game.Tests.Skins
+{
+    [TestFixture]
+    public class TestSceneSkinConfigurationLookup : OsuTestScene
+    {
+        private LegacySkin source1;
+        private LegacySkin source2;
+        private SkinRequester requester;
+
+        [SetUp]
+        public void SetUp() => Schedule(() =>
+        {
+            Add(new SkinProvidingContainer(source1 = new SkinSource())
+                .WithChild(new SkinProvidingContainer(source2 = new SkinSource())
+                    .WithChild(requester = new SkinRequester())));
+        });
+
+        [Test]
+        public void TestBasicLookup()
+        {
+            AddStep("Add config values", () =>
+            {
+                source1.Configuration.ConfigDictionary["Lookup"] = "source1";
+                source2.Configuration.ConfigDictionary["Lookup"] = "source2";
+            });
+
+            AddAssert("Check lookup finds source2", () => requester.GetConfig<string, string>("Lookup")?.Value == "source2");
+        }
+
+        [Test]
+        public void TestFloatLookup()
+        {
+            AddStep("Add config values", () => source1.Configuration.ConfigDictionary["FloatTest"] = "1.1");
+            AddAssert("Check float parse lookup", () => requester.GetConfig<string, float>("FloatTest")?.Value == 1.1f);
+        }
+
+        [Test]
+        public void TestBoolLookup()
+        {
+            AddStep("Add config values", () => source1.Configuration.ConfigDictionary["BoolTest"] = "1");
+            AddAssert("Check bool parse lookup", () => requester.GetConfig<string, bool>("BoolTest")?.Value == true);
+        }
+
+        [Test]
+        public void TestEnumLookup()
+        {
+            AddStep("Add config values", () => source1.Configuration.ConfigDictionary["Test"] = "Test2");
+            AddAssert("Check enum parse lookup", () => requester.GetConfig<LookupType, ValueType>(LookupType.Test)?.Value == ValueType.Test2);
+        }
+
+        [Test]
+        public void TestLookupFailure()
+        {
+            AddAssert("Check lookup failure", () => requester.GetConfig<string, float>("Lookup") == null);
+        }
+
+        [Test]
+        public void TestLookupNull()
+        {
+            AddStep("Add config values", () => source1.Configuration.ConfigDictionary["Lookup"] = null);
+
+            AddAssert("Check lookup null", () =>
+            {
+                var bindable = requester.GetConfig<string, string>("Lookup");
+                return bindable != null && bindable.Value == null;
+            });
+        }
+
+        [Test]
+        public void TestColourLookup()
+        {
+            AddStep("Add config colour", () => source1.Configuration.CustomColours["Lookup"] = Color4.Red);
+            AddAssert("Check colour lookup", () => requester.GetConfig<SkinCustomColourLookup, Color4>(new SkinCustomColourLookup("Lookup"))?.Value == Color4.Red);
+        }
+
+        [Test]
+        public void TestGlobalLookup()
+        {
+            AddAssert("Check combo colours", () => requester.GetConfig<GlobalSkinConfiguration, List<Color4>>(GlobalSkinConfiguration.ComboColours)?.Value?.Count > 0);
+        }
+
+        [Test]
+        public void TestWrongColourType()
+        {
+            AddStep("Add config colour", () => source1.Configuration.CustomColours["Lookup"] = Color4.Red);
+
+            AddAssert("perform incorrect lookup", () =>
+            {
+                try
+                {
+                    requester.GetConfig<SkinCustomColourLookup, int>(new SkinCustomColourLookup("Lookup"));
+                    return false;
+                }
+                catch
+                {
+                    return true;
+                }
+            });
+        }
+
+        public enum LookupType
+        {
+            Test
+        }
+
+        public enum ValueType
+        {
+            Test1,
+            Test2,
+            Test3
+        }
+
+        public class SkinSource : LegacySkin
+        {
+            public SkinSource()
+                : base(new SkinInfo(), null, null, string.Empty)
+            {
+            }
+        }
+
+        public class SkinRequester : Drawable, ISkin
+        {
+            private ISkinSource skin;
+
+            [BackgroundDependencyLoader]
+            private void load(ISkinSource skin)
+            {
+                this.skin = skin;
+            }
+
+            public Drawable GetDrawableComponent(ISkinComponent component) => skin.GetDrawableComponent(component);
+
+            public Texture GetTexture(string componentName) => skin.GetTexture(componentName);
+
+            public SampleChannel GetSample(ISampleInfo sampleInfo) => skin.GetSample(sampleInfo);
+
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => skin.GetConfig<TLookup, TValue>(lookup);
+        }
+    }
+}

osu.Game.Tests/Visual/Gameplay/TestSceneSkinnableDrawable.cs

@@ -7,6 +7,7 @@ using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
@@ -180,7 +181,8 @@ namespace osu.Game.Tests.Visual.Gameplay
         {
             public new Drawable Drawable => base.Drawable;
 
-            public ExposedSkinnableDrawable(string name, Func<ISkinComponent, Drawable> defaultImplementation, Func<ISkinSource, bool> allowFallback = null, ConfineMode confineMode = ConfineMode.ScaleDownToFit)
+            public ExposedSkinnableDrawable(string name, Func<ISkinComponent, Drawable> defaultImplementation, Func<ISkinSource, bool> allowFallback = null,
+                                            ConfineMode confineMode = ConfineMode.ScaleDownToFit)
                 : base(new TestSkinComponent(name), defaultImplementation, allowFallback, confineMode)
             {
             }
@@ -299,7 +301,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             public SampleChannel GetSample(ISampleInfo sampleInfo) => throw new NotImplementedException();
 
-            public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration => throw new NotImplementedException();
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => throw new NotImplementedException();
         }
 
         private class SecondarySource : ISkin
@@ -310,7 +312,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             public SampleChannel GetSample(ISampleInfo sampleInfo) => throw new NotImplementedException();
 
-            public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration => throw new NotImplementedException();
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => throw new NotImplementedException();
         }
 
         [Cached(typeof(ISkinSource))]
@@ -322,7 +324,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             public SampleChannel GetSample(ISampleInfo sampleInfo) => throw new NotImplementedException();
 
-            public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration => throw new NotImplementedException();
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => throw new NotImplementedException();
 
             public event Action SourceChanged;
         }

osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs

@@ -241,7 +241,11 @@ namespace osu.Game.Rulesets.Objects.Drawables
             base.SkinChanged(skin, allowFallback);
 
             if (HitObject is IHasComboInformation combo)
-                AccentColour.Value = skin.GetValue<SkinConfiguration, Color4?>(s => s.ComboColours.Count > 0 ? s.ComboColours[combo.ComboIndex % s.ComboColours.Count] : (Color4?)null) ?? Color4.White;
+            {
+                var comboColours = skin.GetConfig<GlobalSkinConfiguration, List<Color4>>(GlobalSkinConfiguration.ComboColours)?.Value;
+
+                AccentColour.Value = comboColours?.Count > 0 ? comboColours[combo.ComboIndex % comboColours.Count] : Color4.White;
+            }
         }
 
         /// <summary>

osu.Game/Screens/Menu/LogoVisualisation.cs

@@ -122,7 +122,7 @@ namespace osu.Game.Screens.Menu
             Color4 defaultColour = Color4.White.Opacity(0.2f);
 
             if (user.Value?.IsSupporter ?? false)
-                AccentColour = skin.Value.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.ContainsKey("MenuGlow") ? s.CustomColours["MenuGlow"] : (Color4?)null) ?? defaultColour;
+                AccentColour = skin.Value.GetConfig<GlobalSkinColour, Color4>(GlobalSkinColour.MenuGlow)?.Value ?? defaultColour;
             else
                 AccentColour = defaultColour;
         }

osu.Game/Screens/Menu/MenuSideFlashes.cs

@@ -112,7 +112,7 @@ namespace osu.Game.Screens.Menu
             Color4 baseColour = colours.Blue;
 
             if (user.Value?.IsSupporter ?? false)
-                baseColour = skin.Value.GetValue<SkinConfiguration, Color4?>(s => s.CustomColours.ContainsKey("MenuGlow") ? s.CustomColours["MenuGlow"] : (Color4?)null) ?? baseColour;
+                baseColour = skin.Value.GetConfig<GlobalSkinColour, Color4>(GlobalSkinColour.MenuGlow)?.Value ?? baseColour;
 
             // linear colour looks better in this case, so let's use it for now.
             Color4 gradientDark = baseColour.Opacity(0).ToLinear();

osu.Game/Skinning/DefaultLegacySkin.cs

@@ -3,6 +3,7 @@
 
 using osu.Framework.Audio;
 using osu.Framework.IO.Stores;
+using osuTK.Graphics;
 
 namespace osu.Game.Skinning
 {
@@ -11,6 +12,7 @@ namespace osu.Game.Skinning
         public DefaultLegacySkin(IResourceStore<byte[]> storage, AudioManager audioManager)
             : base(Info, storage, audioManager, string.Empty)
         {
+            Configuration.CustomColours["SliderBall"] = new Color4(2, 170, 255, 255);
         }
 
         public static SkinInfo Info { get; } = new SkinInfo

osu.Game/Skinning/DefaultSkin.cs

@@ -1,7 +1,8 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// 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.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Textures;
 using osu.Game.Audio;
@@ -21,5 +22,7 @@ namespace osu.Game.Skinning
         public override Texture GetTexture(string componentName) => null;
 
         public override SampleChannel GetSample(ISampleInfo sampleInfo) => null;
+
+        public override IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => null;
     }
 }

osu.Game/Skinning/DefaultSkinConfiguration.cs

@@ -12,8 +12,6 @@ namespace osu.Game.Skinning
     {
         public DefaultSkinConfiguration()
         {
-            HitCircleFont = "default";
-
             ComboColours.AddRange(new[]
             {
                 new Color4(17, 136, 170, 255),
@@ -21,8 +19,6 @@ namespace osu.Game.Skinning
                 new Color4(204, 102, 0, 255),
                 new Color4(121, 9, 13, 255)
             });
-
-            CursorExpand = true;
         }
     }
 }

osu.Game/Skinning/GameplaySkinComponent.cs

@@ -5,7 +5,7 @@ using System.Linq;
 
 namespace osu.Game.Skinning
 {
-    public class GameplaySkinComponent<T> : ISkinComponent where T : struct
+    public class GameplaySkinComponent<T> : ISkinComponent
     {
         public readonly T Component;
 

osu.Game/Skinning/GlobalSkinColour.cs

@@ -0,0 +1,10 @@
+// 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.
+
+namespace osu.Game.Skinning
+{
+    public enum GlobalSkinColour
+    {
+        MenuGlow
+    }
+}

osu.Game/Skinning/GlobalSkinConfiguration.cs

@@ -0,0 +1,10 @@
+// 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.
+
+namespace osu.Game.Skinning
+{
+    public enum GlobalSkinConfiguration
+    {
+        ComboColours
+    }
+}

osu.Game/Skinning/ISkin.cs

@@ -1,8 +1,9 @@
 // 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.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Textures;
 using osu.Game.Audio;
@@ -14,12 +15,36 @@ namespace osu.Game.Skinning
     /// </summary>
     public interface ISkin
     {
+        /// <summary>
+        /// Retrieve a <see cref="Drawable"/> component implementation.
+        /// </summary>
+        /// <param name="component">The requested component.</param>
+        /// <returns>A drawable representation for the requested component, or null if unavailable.</returns>
+        [CanBeNull]
         Drawable GetDrawableComponent(ISkinComponent component);
 
+        /// <summary>
+        /// Retrieve a <see cref="Texture"/>.
+        /// </summary>
+        /// <param name="componentName">The requested texture.</param>
+        /// <returns>A matching texture, or null if unavailable.</returns>
+        [CanBeNull]
         Texture GetTexture(string componentName);
 
+        /// <summary>
+        /// Retrieve a <see cref="SampleChannel"/>.
+        /// </summary>
+        /// <param name="sampleInfo">The requested sample.</param>
+        /// <returns>A matching sample channel, or null if unavailable.</returns>
+        [CanBeNull]
         SampleChannel GetSample(ISampleInfo sampleInfo);
 
-        TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration;
+        /// <summary>
+        /// Retrieve a configuration value.
+        /// </summary>
+        /// <param name="lookup">The requested configuration value.</param>
+        /// <returns>A matching value boxed in an <see cref="IBindable{TValue}"/>, or null if unavailable.</returns>
+        [CanBeNull]
+        IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup);
     }
 }

osu.Game/Skinning/LegacySkin.cs

@@ -1,10 +1,13 @@
 // 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.Collections.Generic;
 using System.IO;
 using System.Linq;
+using JetBrains.Annotations;
 using osu.Framework.Audio;
 using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Textures;
 using osu.Framework.IO.Stores;
@@ -16,29 +19,32 @@ namespace osu.Game.Skinning
 {
     public class LegacySkin : Skin
     {
+        [CanBeNull]
         protected TextureStore Textures;
 
+        [CanBeNull]
         protected IResourceStore<SampleChannel> Samples;
 
         public LegacySkin(SkinInfo skin, IResourceStore<byte[]> storage, AudioManager audioManager)
             : this(skin, new LegacySkinResourceStore<SkinFileInfo>(skin, storage), audioManager, "skin.ini")
         {
-            // defaults should only be applied for non-beatmap skins (which are parsed via this constructor).
-            if (!Configuration.CustomColours.ContainsKey("SliderBall")) Configuration.CustomColours["SliderBall"] = new Color4(2, 170, 255, 255);
         }
 
         protected LegacySkin(SkinInfo skin, IResourceStore<byte[]> storage, AudioManager audioManager, string filename)
             : base(skin)
         {
-            Stream stream = storage.GetStream(filename);
+            Stream stream = storage?.GetStream(filename);
             if (stream != null)
                 using (StreamReader reader = new StreamReader(stream))
                     Configuration = new LegacySkinDecoder().Decode(reader);
             else
                 Configuration = new DefaultSkinConfiguration();
 
-            Samples = audioManager.GetSampleStore(storage);
+            if (storage != null)
-            Textures = new TextureStore(new TextureLoaderStore(storage));
+            {
+                Samples = audioManager?.GetSampleStore(storage);
+                Textures = new TextureStore(new TextureLoaderStore(storage));
+            }
         }
 
         protected override void Dispose(bool isDisposing)
@@ -48,6 +54,52 @@ namespace osu.Game.Skinning
             Samples?.Dispose();
         }
 
+        public override IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup)
+        {
+            switch (lookup)
+            {
+                case GlobalSkinConfiguration global:
+                    switch (global)
+                    {
+                        case GlobalSkinConfiguration.ComboColours:
+                            return SkinUtils.As<TValue>(new Bindable<List<Color4>>(Configuration.ComboColours));
+                    }
+
+                    break;
+
+                case GlobalSkinColour colour:
+                    return SkinUtils.As<TValue>(getCustomColour(colour.ToString()));
+
+                case SkinCustomColourLookup customColour:
+                    return SkinUtils.As<TValue>(getCustomColour(customColour.Lookup.ToString()));
+
+                default:
+                    try
+                    {
+                        if (Configuration.ConfigDictionary.TryGetValue(lookup.ToString(), out var val))
+                        {
+                            // special case for handling skins which use 1 or 0 to signify a boolean state.
+                            if (typeof(TValue) == typeof(bool))
+                                val = val == "1" ? "true" : "false";
+
+                            var bindable = new Bindable<TValue>();
+                            if (val != null)
+                                bindable.Parse(val);
+                            return bindable;
+                        }
+                    }
+                    catch
+                    {
+                    }
+
+                    break;
+            }
+
+            return null;
+        }
+
+        private IBindable<Color4> getCustomColour(string lookup) => Configuration.CustomColours.TryGetValue(lookup, out var col) ? new Bindable<Color4>(col) : null;
+
         public override Drawable GetDrawableComponent(ISkinComponent component)
         {
             switch (component)
@@ -79,12 +131,12 @@ namespace osu.Game.Skinning
             componentName = getFallbackName(componentName);
 
             float ratio = 2;
-            var texture = Textures.Get($"{componentName}@2x");
+            var texture = Textures?.Get($"{componentName}@2x");
 
             if (texture == null)
             {
                 ratio = 1;
-                texture = Textures.Get(componentName);
+                texture = Textures?.Get(componentName);
             }
 
             if (texture != null)
@@ -97,7 +149,7 @@ namespace osu.Game.Skinning
         {
             foreach (var lookup in sampleInfo.LookupNames)
             {
-                var sample = Samples.Get(getFallbackName(lookup));
+                var sample = Samples?.Get(getFallbackName(lookup));
 
                 if (sample != null)
                     return sample;
@@ -105,7 +157,7 @@ namespace osu.Game.Skinning
 
             if (sampleInfo is HitSampleInfo hsi)
                 // Try fallback to non-bank samples.
-                return Samples.Get(hsi.Name);
+                return Samples?.Get(hsi.Name);
 
             return null;
         }

osu.Game/Skinning/LegacySkinDecoder.cs

@@ -14,47 +14,31 @@ namespace osu.Game.Skinning
 
         protected override void ParseLine(DefaultSkinConfiguration skin, Section section, string line)
         {
-            line = StripComments(line);
+            if (section != Section.Colours)
-
-            var pair = SplitKeyVal(line);
-
-            switch (section)
             {
-                case Section.General:
+                line = StripComments(line);
-                    switch (pair.Key)
-                    {
-                        case @"Name":
-                            skin.SkinInfo.Name = pair.Value;
-                            break;
 
-                        case @"Author":
+                var pair = SplitKeyVal(line);
-                            skin.SkinInfo.Creator = pair.Value;
-                            break;
 
-                        case @"CursorExpand":
+                switch (section)
-                            skin.CursorExpand = pair.Value != "0";
+                {
-                            break;
+                    case Section.General:
+                        switch (pair.Key)
+                        {
+                            case @"Name":
+                                skin.SkinInfo.Name = pair.Value;
+                                return;
 
-                        case @"SliderBorderSize":
+                            case @"Author":
-                            skin.SliderBorderSize = Parsing.ParseFloat(pair.Value);
+                                skin.SkinInfo.Creator = pair.Value;
-                            break;
+                                return;
-                    }
+                        }
 
-                    break;
+                        break;
+                }
 
-                case Section.Fonts:
+                if (!string.IsNullOrEmpty(pair.Key))
-                    switch (pair.Key)
+                    skin.ConfigDictionary[pair.Key] = pair.Value;
-                    {
-                        case "HitCirclePrefix":
-                            skin.HitCircleFont = pair.Value;
-                            break;
-
-                        case "HitCircleOverlap":
-                            skin.HitCircleOverlap = int.Parse(pair.Value);
-                            break;
-                    }
-
-                    break;
             }
 
             base.ParseLine(skin, section, line);

osu.Game/Skinning/Skin.cs

@@ -1,8 +1,9 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// 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 osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Textures;
 using osu.Game.Audio;
@@ -13,7 +14,7 @@ namespace osu.Game.Skinning
     {
         public readonly SkinInfo SkinInfo;
 
-        public virtual SkinConfiguration Configuration { get; protected set; }
+        public SkinConfiguration Configuration { get; protected set; }
 
         public abstract Drawable GetDrawableComponent(ISkinComponent componentName);
 
@@ -21,8 +22,7 @@ namespace osu.Game.Skinning
 
         public abstract Texture GetTexture(string componentName);
 
-        public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration
+        public abstract IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup);
-            => Configuration is TConfiguration conf ? query.Invoke(conf) : default;
 
         protected Skin(SkinInfo skin)
         {

osu.Game/Skinning/SkinConfigManager.cs

@@ -0,0 +1,16 @@
+// 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.Configuration;
+
+namespace osu.Game.Skinning
+{
+    public class SkinConfigManager<T> : ConfigManager<T> where T : struct
+    {
+        protected override void PerformLoad()
+        {
+        }
+
+        protected override bool PerformSave() => false;
+    }
+}

osu.Game/Skinning/SkinConfiguration.cs

@@ -18,14 +18,6 @@ namespace osu.Game.Skinning
 
         public Dictionary<string, Color4> CustomColours { get; set; } = new Dictionary<string, Color4>();
 
-        public string HitCircleFont { get; set; }
+        public readonly Dictionary<string, string> ConfigDictionary = new Dictionary<string, string>();
-
-        public int HitCircleOverlap { get; set; }
-
-        public float? SliderBorderSize { get; set; }
-
-        public float? SliderPathRadius { get; set; }
-
-        public bool? CursorExpand { get; set; }
     }
 }

osu.Game/Skinning/SkinCustomColourLookup.cs

@@ -0,0 +1,15 @@
+// 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.
+
+namespace osu.Game.Skinning
+{
+    public class SkinCustomColourLookup
+    {
+        public readonly object Lookup;
+
+        public SkinCustomColourLookup(object lookup)
+        {
+            Lookup = lookup;
+        }
+    }
+}

osu.Game/Skinning/SkinManager.cs

@@ -1,4 +1,4 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// 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;
@@ -131,6 +131,6 @@ namespace osu.Game.Skinning
 
         public SampleChannel GetSample(ISampleInfo sampleInfo) => CurrentSkin.Value.GetSample(sampleInfo);
 
-        public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration => CurrentSkin.Value.GetValue(query);
+        public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => CurrentSkin.Value.GetConfig<TLookup, TValue>(lookup);
     }
 }

osu.Game/Skinning/SkinProvidingContainer.cs

@@ -4,6 +4,7 @@
 using System;
 using osu.Framework.Allocation;
 using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Textures;
@@ -64,13 +65,16 @@ namespace osu.Game.Skinning
             return fallbackSource?.GetSample(sampleInfo);
         }
 
-        public TValue GetValue<TConfiguration, TValue>(Func<TConfiguration, TValue> query) where TConfiguration : SkinConfiguration
+        public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup)
         {
-            TValue val;
+            if (AllowConfigurationLookup && skin != null)
-            if (AllowConfigurationLookup && skin != null && (val = skin.GetValue(query)) != null)
+            {
-                return val;
+                var bindable = skin.GetConfig<TLookup, TValue>(lookup);
+                if (bindable != null)
+                    return bindable;
+            }
 
-            return fallbackSource == null ? default : fallbackSource.GetValue(query);
+            return fallbackSource?.GetConfig<TLookup, TValue>(lookup);
         }
 
         protected virtual void TriggerSourceChanged() => SourceChanged?.Invoke();

osu.Game/Skinning/SkinUtils.cs

@@ -0,0 +1,21 @@
+// 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;
+
+namespace osu.Game.Skinning
+{
+    /// <summary>
+    /// Contains helper methods to assist in implementing <see cref="ISkin"/>s.
+    /// </summary>
+    public static class SkinUtils
+    {
+        /// <summary>
+        /// Converts an <see cref="object"/> to a <see cref="Bindable{TValue}"/>. Used for returning configuration values of specific types.
+        /// </summary>
+        /// <param name="value">The value.</param>
+        /// <typeparam name="TValue">The type of value <paramref name="value"/>, and the type of the resulting bindable.</typeparam>
+        /// <returns>The resulting bindable.</returns>
+        public static Bindable<TValue> As<TValue>(object value) => (Bindable<TValue>)value;
+    }
+}