Merge branch 'master' into fix-beatmap-carousel-lag

osu-framework

@@ -1 +1 @@
-Subproject commit 4fc866eee3803f88b155150e32e021b9c21e647f
+Subproject commit 9cd6968a8c4d27415808f5e770d24fec5a44485f

osu.Desktop.Deploy/osu.Desktop.Deploy.csproj

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="..\osu.Game.props" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -22,7 +22,6 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
-    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <PlatformTarget>AnyCPU</PlatformTarget>
@@ -102,9 +101,6 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\osu.licenseheader">
-      <Link>osu.licenseheader</Link>
-    </None>
     <None Include="App.config">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>

osu.Desktop/osu.Desktop.csproj

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="12.0">
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="14.0">
+  <Import Project="..\osu.Game.props" />
   <PropertyGroup>
     <ProjectGuid>{419659FD-72EA-4678-9EB8-B22A746CED70}</ProjectGuid>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -62,7 +63,6 @@
     <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
     <Commandlineparameters>
     </Commandlineparameters>
-    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>none</DebugType>
@@ -98,7 +98,6 @@
     <DebugType>full</DebugType>
     <PlatformTarget>AnyCPU</PlatformTarget>
     <UseVSHostingProcess>false</UseVSHostingProcess>
-    <LangVersion>6</LangVersion>
     <ErrorReport>prompt</ErrorReport>
     <StartArguments>--tests</StartArguments>
   </PropertyGroup>
@@ -174,9 +173,6 @@
     <Reference Include="System.Windows.Forms" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\osu.licenseheader">
-      <Link>osu.licenseheader</Link>
-    </None>
     <None Include="app.config" />
     <None Include="OpenTK.dll.config" />
     <None Include="osu!.res" />

osu.Game.Rulesets.Catch/Beatmaps/CatchBeatmapProcessor.cs

@@ -1,8 +1,14 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
+using System.Collections.Generic;
+using System.Linq;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Catch.UI;
+using osu.Game.Rulesets.Objects.Types;
+using OpenTK;
 
 namespace osu.Game.Rulesets.Catch.Beatmaps
 {
@@ -18,6 +24,8 @@ namespace osu.Game.Rulesets.Catch.Beatmaps
 
             CatchHitObject lastObj = null;
 
+            initialiseHyperDash(beatmap.HitObjects);
+
             foreach (var obj in beatmap.HitObjects)
             {
                 if (obj.NewCombo)
@@ -34,5 +42,49 @@ namespace osu.Game.Rulesets.Catch.Beatmaps
                 lastObj = obj;
             }
         }
+
+        private void initialiseHyperDash(List<CatchHitObject> objects)
+        {
+            // todo: add difficulty adjust.
+            double halfCatcherWidth = CatcherArea.CATCHER_SIZE * (objects.FirstOrDefault()?.Scale ?? 1) / CatchPlayfield.BASE_WIDTH / 2;
+
+            int lastDirection = 0;
+            double lastExcess = halfCatcherWidth;
+
+            int objCount = objects.Count;
+
+            for (int i = 0; i < objCount - 1; i++)
+            {
+                CatchHitObject currentObject = objects[i];
+
+                // not needed?
+                // if (currentObject is TinyDroplet) continue;
+
+                CatchHitObject nextObject = objects[i + 1];
+
+                // while (nextObject is TinyDroplet)
+                // {
+                //     if (++i == objCount - 1) break;
+                //     nextObject = objects[i + 1];
+                // }
+
+                int thisDirection = nextObject.X > currentObject.X ? 1 : -1;
+                double timeToNext = nextObject.StartTime - ((currentObject as IHasEndTime)?.EndTime ?? currentObject.StartTime) - 4;
+                double distanceToNext = Math.Abs(nextObject.X - currentObject.X) - (lastDirection == thisDirection ? lastExcess : halfCatcherWidth);
+
+                if (timeToNext * CatcherArea.Catcher.BASE_SPEED < distanceToNext)
+                {
+                    currentObject.HyperDashTarget = nextObject;
+                    lastExcess = halfCatcherWidth;
+                }
+                else
+                {
+                    //currentObject.DistanceToHyperDash = timeToNext - distanceToNext;
+                    lastExcess = MathHelper.Clamp(timeToNext - distanceToNext, 0, halfCatcherWidth);
+                }
+
+                lastDirection = thisDirection;
+            }
+        }
     }
 }

osu.Game.Rulesets.Catch/Objects/CatchHitObject.cs

@@ -27,6 +27,16 @@ namespace osu.Game.Rulesets.Catch.Objects
 
         public float Scale { get; set; } = 1;
 
+        /// <summary>
+        /// Whether this fruit can initiate a hyperdash.
+        /// </summary>
+        public bool HyperDash => HyperDashTarget != null;
+
+        /// <summary>
+        /// The target fruit if we are to initiate a hyperdash.
+        /// </summary>
+        public CatchHitObject HyperDashTarget;
+
         public override void ApplyDefaults(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
         {
             base.ApplyDefaults(controlPointInfo, difficulty);

osu.Game.Rulesets.Catch/Objects/Drawable/DrawableFruit.cs

@@ -7,6 +7,7 @@ using osu.Framework.Graphics.Containers;
 using osu.Framework.MathUtils;
 using osu.Game.Rulesets.Catch.Objects.Drawable.Pieces;
 using OpenTK;
+using OpenTK.Graphics;
 
 namespace osu.Game.Rulesets.Catch.Objects.Drawable
 {
@@ -70,6 +71,20 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawable
                     }
                 }
             };
+
+            if (HitObject.HyperDash)
+            {
+                Add(new Pulp
+                {
+                    RelativePositionAxes = Axes.Both,
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    AccentColour = Color4.Red,
+                    Blending = BlendingMode.Additive,
+                    Alpha = 0.5f,
+                    Scale = new Vector2(2)
+                });
+            }
         }
     }
 }

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

@@ -17,6 +17,7 @@ namespace osu.Game.Rulesets.Catch.Tests
     internal class TestCaseCatcherArea : OsuTestCase
     {
         private RulesetInfo catchRuleset;
+        private TestCatcherArea catcherArea;
 
         public override IReadOnlyList<Type> RequiredTypes => new[]
         {
@@ -26,6 +27,7 @@ namespace osu.Game.Rulesets.Catch.Tests
         public TestCaseCatcherArea()
         {
             AddSliderStep<float>("CircleSize", 0, 8, 5, createCatcher);
+            AddToggleStep("Hyperdash", t => catcherArea.ToggleHyperDash(t));
         }
 
         private void createCatcher(float size)
@@ -33,7 +35,7 @@ namespace osu.Game.Rulesets.Catch.Tests
             Child = new CatchInputManager(catchRuleset)
             {
                 RelativeSizeAxes = Axes.Both,
-                Child = new CatcherArea(new BeatmapDifficulty { CircleSize = size })
+                Child = catcherArea = new TestCatcherArea(new BeatmapDifficulty { CircleSize = size })
                 {
                     Anchor = Anchor.CentreLeft,
                     Origin = Anchor.BottomLeft
@@ -46,5 +48,15 @@ namespace osu.Game.Rulesets.Catch.Tests
         {
             catchRuleset = rulesets.GetRuleset(2);
         }
+
+        private class TestCatcherArea : CatcherArea
+        {
+            public TestCatcherArea(BeatmapDifficulty beatmapDifficulty)
+                : base(beatmapDifficulty)
+            {
+            }
+
+            public void ToggleHyperDash(bool status) => MovableCatcher.HyperDashModifier = status ? 2 : 1;
+        }
     }
 }

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

@@ -0,0 +1,30 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using NUnit.Framework;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Catch.Objects;
+
+namespace osu.Game.Rulesets.Catch.Tests
+{
+    [TestFixture]
+    [Ignore("getting CI working")]
+    public class TestCaseHyperdash : Game.Tests.Visual.TestCasePlayer
+    {
+        public TestCaseHyperdash()
+            : base(typeof(CatchRuleset))
+        {
+        }
+
+        protected override Beatmap CreateBeatmap()
+        {
+            var beatmap = new Beatmap();
+
+            for (int i = 0; i < 512; i++)
+                if (i % 5 < 3)
+                    beatmap.HitObjects.Add(new Fruit { X = i % 10 < 5 ? 0.02f : 0.98f, StartTime = i * 100, NewCombo = i % 8 == 0 });
+
+            return beatmap;
+        }
+    }
+}

osu.Game.Rulesets.Catch/UI/CatchPlayfield.cs

@@ -15,7 +15,7 @@ namespace osu.Game.Rulesets.Catch.UI
 {
     public class CatchPlayfield : ScrollingPlayfield
     {
-        public static readonly float BASE_WIDTH = 512;
+        public const float BASE_WIDTH = 512;
 
         protected override Container<Drawable> Content => content;
         private readonly Container<Drawable> content;
@@ -51,7 +51,7 @@ namespace osu.Game.Rulesets.Catch.UI
             };
         }
 
-        public bool CheckIfWeCanCatch(CatchHitObject obj) => catcherArea.CanCatch(obj);
+        public bool CheckIfWeCanCatch(CatchHitObject obj) => catcherArea.AttemptCatch(obj);
 
         public override void Add(DrawableHitObject h)
         {

osu.Game.Rulesets.Catch/UI/CatcherArea.cs

@@ -14,6 +14,7 @@ using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
 using OpenTK;
+using OpenTK.Graphics;
 
 namespace osu.Game.Rulesets.Catch.UI
 {
@@ -21,18 +22,18 @@ namespace osu.Game.Rulesets.Catch.UI
     {
         public const float CATCHER_SIZE = 172;
 
-        private readonly Catcher catcher;
+        protected readonly Catcher MovableCatcher;
 
         public Container ExplodingFruitTarget
         {
-            set { catcher.ExplodingFruitTarget = value; }
+            set { MovableCatcher.ExplodingFruitTarget = value; }
         }
 
         public CatcherArea(BeatmapDifficulty difficulty = null)
         {
             RelativeSizeAxes = Axes.X;
             Height = CATCHER_SIZE;
-            Child = catcher = new Catcher(difficulty)
+            Child = MovableCatcher = new Catcher(difficulty)
             {
                 AdditiveTarget = this,
             };
@@ -41,17 +42,17 @@ namespace osu.Game.Rulesets.Catch.UI
         public void Add(DrawableHitObject fruit, Vector2 absolutePosition)
         {
             fruit.RelativePositionAxes = Axes.None;
-            fruit.Position = new Vector2(catcher.ToLocalSpace(absolutePosition).X - catcher.DrawSize.X / 2, 0);
+            fruit.Position = new Vector2(MovableCatcher.ToLocalSpace(absolutePosition).X - MovableCatcher.DrawSize.X / 2, 0);
 
             fruit.Anchor = Anchor.TopCentre;
             fruit.Origin = Anchor.BottomCentre;
             fruit.Scale *= 0.7f;
             fruit.LifetimeEnd = double.MaxValue;
 
-            catcher.Add(fruit);
+            MovableCatcher.Add(fruit);
         }
 
-        public bool CanCatch(CatchHitObject obj) => Math.Abs(catcher.Position.X - obj.X) < catcher.DrawSize.X * Math.Abs(catcher.Scale.X) / DrawSize.X / 2;
+        public bool AttemptCatch(CatchHitObject obj) => MovableCatcher.AttemptCatch(obj);
 
         public class Catcher : Container, IKeyBindingHandler<CatchAction>
         {
@@ -105,14 +106,35 @@ namespace osu.Game.Rulesets.Catch.UI
 
                     dashing = value;
 
-                    if (dashing)
+                    Trail |= dashing;
-                        Schedule(addAdditiveSprite);
                 }
             }
 
-            private void addAdditiveSprite()
+            private bool trail;
+
+            /// <summary>
+            /// Activate or deactive the trail. Will be automatically deactivated when conditions to keep the trail displayed are no longer met.
+            /// </summary>
+            protected bool Trail
             {
-                if (!dashing || AdditiveTarget == null) return;
+                get { return trail; }
+                set
+                {
+                    if (value == trail) return;
+
+                    trail = value;
+
+                    if (Trail)
+                        beginTrail();
+                }
+            }
+
+            private void beginTrail()
+            {
+                Trail &= dashing || HyperDashing;
+                Trail &= AdditiveTarget != null;
+
+                if (!Trail) return;
 
                 var additive = createCatcherSprite();
 
@@ -120,6 +142,7 @@ namespace osu.Game.Rulesets.Catch.UI
                 additive.OriginPosition = additive.OriginPosition + new Vector2(DrawWidth / 2, 0); // also temporary to align sprite correctly.
                 additive.Position = Position;
                 additive.Scale = Scale;
+                additive.Colour = HyperDashing ? Color4.Red : Color4.White;
                 additive.RelativePositionAxes = RelativePositionAxes;
                 additive.Blending = BlendingMode.Additive;
 
@@ -127,7 +150,7 @@ namespace osu.Game.Rulesets.Catch.UI
 
                 additive.FadeTo(0.4f).FadeOut(800, Easing.OutQuint).Expire();
 
-                Scheduler.AddDelayed(addAdditiveSprite, 50);
+                Scheduler.AddDelayed(beginTrail, HyperDashing ? 25 : 50);
             }
 
             private Sprite createCatcherSprite() => new Sprite
@@ -138,6 +161,10 @@ namespace osu.Game.Rulesets.Catch.UI
                 OriginPosition = new Vector2(-3, 10) // temporary until the sprite is aligned correctly.
             };
 
+            /// <summary>
+            /// Add a caught fruit to the catcher's stack.
+            /// </summary>
+            /// <param name="fruit">The fruit that was caught.</param>
             public void Add(DrawableHitObject fruit)
             {
                 float distance = fruit.DrawSize.X / 2 * fruit.Scale.X;
@@ -150,10 +177,80 @@ namespace osu.Game.Rulesets.Catch.UI
 
                 caughtFruit.Add(fruit);
 
-                if (((CatchHitObject)fruit.HitObject).LastInCombo)
+                var catchObject = (CatchHitObject)fruit.HitObject;
+
+                if (catchObject.LastInCombo)
                     explode();
             }
 
+            /// <summary>
+            /// Let the catcher attempt to catch a fruit.
+            /// </summary>
+            /// <param name="fruit">The fruit to catch.</param>
+            /// <returns>Whether the catch is possible.</returns>
+            public bool AttemptCatch(CatchHitObject fruit)
+            {
+                const double relative_catcher_width = CATCHER_SIZE / 2;
+
+                // this stuff wil disappear once we move fruit to non-relative coordinate space in the future.
+                var catchObjectPosition = fruit.X * CatchPlayfield.BASE_WIDTH;
+                var catcherPosition = Position.X * CatchPlayfield.BASE_WIDTH;
+
+                var validCatch =
+                    catchObjectPosition >= catcherPosition - relative_catcher_width / 2 &&
+                    catchObjectPosition <= catcherPosition + relative_catcher_width / 2;
+
+                if (validCatch && fruit.HyperDash)
+                {
+                    HyperDashModifier = Math.Abs(fruit.HyperDashTarget.X - fruit.X) / Math.Abs(fruit.HyperDashTarget.StartTime - fruit.StartTime) / BASE_SPEED;
+                    HyperDashDirection = fruit.HyperDashTarget.X - fruit.X;
+                }
+                else
+                    HyperDashModifier = 1;
+
+                return validCatch;
+            }
+
+            /// <summary>
+            /// Whether we are hypderdashing or not.
+            /// </summary>
+            public bool HyperDashing => hyperDashModifier != 1;
+
+            private double hyperDashModifier = 1;
+
+            /// <summary>
+            /// The direction in which hyperdash is allowed. 0 allows both directions.
+            /// </summary>
+            public double HyperDashDirection;
+
+            /// <summary>
+            /// The speed modifier resultant from hyperdash. Will trigger hyperdash when not equal to 1.
+            /// </summary>
+            public double HyperDashModifier
+            {
+                get { return hyperDashModifier; }
+                set
+                {
+                    if (value == hyperDashModifier) return;
+                    hyperDashModifier = value;
+
+                    const float transition_length = 180;
+
+                    if (HyperDashing)
+                    {
+                        this.FadeColour(Color4.OrangeRed, transition_length, Easing.OutQuint);
+                        this.FadeTo(0.2f, transition_length, Easing.OutQuint);
+                        Trail = true;
+                    }
+                    else
+                    {
+                        HyperDashDirection = 0;
+                        this.FadeColour(Color4.White, transition_length, Easing.OutQuint);
+                        this.FadeTo(1, transition_length, Easing.OutQuint);
+                    }
+                }
+            }
+
             public bool OnPressed(CatchAction action)
             {
                 switch (action)
@@ -201,10 +298,15 @@ namespace osu.Game.Rulesets.Catch.UI
 
                 if (currentDirection == 0) return;
 
+                var direction = Math.Sign(currentDirection);
+
                 double dashModifier = Dashing ? 1 : 0.5;
 
-                Scale = new Vector2(Math.Abs(Scale.X) * Math.Sign(currentDirection), Scale.Y);
+                if (hyperDashModifier != 1 && (HyperDashDirection == 0 || direction == Math.Sign(HyperDashDirection)))
-                X = (float)MathHelper.Clamp(X + Math.Sign(currentDirection) * Clock.ElapsedFrameTime * BASE_SPEED * dashModifier, 0, 1);
+                    dashModifier = hyperDashModifier;
+
+                Scale = new Vector2(Math.Abs(Scale.X) * direction, Scale.Y);
+                X = (float)MathHelper.Clamp(X + direction * Clock.ElapsedFrameTime * BASE_SPEED * dashModifier, 0, 1);
             }
 
             private void explode()

osu.Game.Rulesets.Catch/osu.Game.Rulesets.Catch.csproj

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="..\osu.Game.props" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -21,7 +21,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
-    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -67,6 +66,7 @@
     <Compile Include="Tests\TestCaseCatchStacker.cs" />
     <Compile Include="Tests\TestCasePerformancePoints.cs" />
     <Compile Include="Tests\TestCaseCatchPlayer.cs" />
+    <Compile Include="Tests\TestCaseHyperdash.cs" />
     <Compile Include="UI\CatcherArea.cs" />
     <Compile Include="UI\CatchRulesetContainer.cs" />
     <Compile Include="UI\CatchPlayfield.cs" />
@@ -74,9 +74,6 @@
     <Compile Include="Mods\CatchMod.cs" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\osu.licenseheader">
-      <Link>osu.licenseheader</Link>
-    </None>
     <None Include="app.config" />
     <None Include="OpenTK.dll.config" />
     <None Include="packages.config" />

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

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="..\osu.Game.props" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -21,7 +21,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
-    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -99,9 +98,6 @@
     <Compile Include="Timing\ManiaSpeedAdjustmentContainer.cs" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\osu.licenseheader">
-      <Link>osu.licenseheader</Link>
-    </None>
     <None Include="app.config" />
     <None Include="OpenTK.dll.config" />
     <None Include="packages.config" />

osu.Game.Rulesets.Osu/Edit/OsuEditPlayfield.cs

@@ -0,0 +1,13 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics.Cursor;
+using osu.Game.Rulesets.Osu.UI;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public class OsuEditPlayfield : OsuPlayfield
+    {
+        protected override CursorContainer CreateCursor() => null;
+    }
+}

osu.Game.Rulesets.Osu/Edit/OsuEditRulesetContainer.cs

@@ -0,0 +1,19 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Osu.UI;
+using osu.Game.Rulesets.UI;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public class OsuEditRulesetContainer : OsuRulesetContainer
+    {
+        public OsuEditRulesetContainer(Ruleset ruleset, WorkingBeatmap beatmap, bool isForCurrentRuleset)
+            : base(ruleset, beatmap, isForCurrentRuleset)
+        {
+        }
+
+        protected override Playfield CreatePlayfield() => new OsuEditPlayfield();
+    }
+}

osu.Game.Rulesets.Osu/Edit/OsuHitObjectComposer.cs

@@ -0,0 +1,29 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System.Collections.Generic;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Edit.Tools;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.UI;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public class OsuHitObjectComposer : HitObjectComposer
+    {
+        public OsuHitObjectComposer(Ruleset ruleset)
+            : base(ruleset)
+        {
+        }
+
+        protected override RulesetContainer CreateRulesetContainer(Ruleset ruleset, WorkingBeatmap beatmap) => new OsuEditRulesetContainer(ruleset, beatmap, true);
+
+        protected override IReadOnlyList<ICompositionTool> CompositionTools => new ICompositionTool[]
+        {
+            new HitObjectCompositionTool<HitCircle>(),
+            new HitObjectCompositionTool<Slider>(),
+            new HitObjectCompositionTool<Spinner>()
+        };
+    }
+}

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -16,6 +16,8 @@ using osu.Game.Overlays.Settings;
 using osu.Framework.Input.Bindings;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.Osu.Scoring;
+using osu.Game.Rulesets.Osu.Edit;
+using osu.Game.Rulesets.Edit;
 
 namespace osu.Game.Rulesets.Osu
 {
@@ -118,6 +120,8 @@ namespace osu.Game.Rulesets.Osu
 
         public override PerformanceCalculator CreatePerformanceCalculator(Beatmap beatmap, Score score) => new OsuPerformanceCalculator(this, beatmap, score);
 
+        public override HitObjectComposer CreateHitObjectComposer() => new OsuHitObjectComposer(this);
+
         public override string Description => "osu!";
 
         public override SettingsSubsection CreateSettings() => new OsuSettings();

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

@@ -13,6 +13,7 @@ using System.Linq;
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Osu.Judgements;
 using osu.Game.Rulesets.Osu.UI.Cursor;
+using osu.Framework.Graphics.Cursor;
 
 namespace osu.Game.Rulesets.Osu.UI
 {
@@ -65,7 +66,10 @@ namespace osu.Game.Rulesets.Osu.UI
         protected override void LoadComplete()
         {
             base.LoadComplete();
-            AddInternal(new GameplayCursor());
+
+            var cursor = CreateCursor();
+            if (cursor != null)
+                AddInternal(cursor);
         }
 
         public override void Add(DrawableHitObject h)
@@ -102,5 +106,7 @@ namespace osu.Game.Rulesets.Osu.UI
 
             judgementLayer.Add(explosion);
         }
+
+        protected virtual CursorContainer CreateCursor() => new GameplayCursor();
     }
 }

osu.Game.Rulesets.Osu/osu.Game.Rulesets.Osu.csproj

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="..\osu.Game.props" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -22,7 +22,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
-    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -49,6 +48,9 @@
   <ItemGroup>
     <Compile Include="Beatmaps\OsuBeatmapConverter.cs" />
     <Compile Include="Beatmaps\OsuBeatmapProcessor.cs" />
+    <Compile Include="Edit\OsuEditPlayfield.cs" />
+    <Compile Include="Edit\OsuEditRulesetContainer.cs" />
+    <Compile Include="Edit\OsuHitObjectComposer.cs" />
     <Compile Include="Objects\Drawables\DrawableOsuHitObject.cs" />
     <Compile Include="Objects\Drawables\Connections\ConnectionRenderer.cs" />
     <Compile Include="Objects\Drawables\Connections\FollowPointRenderer.cs" />
@@ -105,9 +107,6 @@
     <Compile Include="Replays\OsuAutoGeneratorBase.cs" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\osu.licenseheader">
-      <Link>osu.licenseheader</Link>
-    </None>
     <None Include="app.config" />
     <None Include="OpenTK.dll.config" />
     <None Include="packages.config" />

osu.Game.Rulesets.Taiko/osu.Game.Rulesets.Taiko.csproj

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="..\osu.Game.props" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -21,7 +21,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
-    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -96,9 +95,6 @@
     <Compile Include="Mods\TaikoMod.cs" />
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\osu.licenseheader">
-      <Link>osu.licenseheader</Link>
-    </None>
     <None Include="app.config" />
     <None Include="OpenTK.dll.config" />
     <None Include="packages.config" />

osu.Game.Tests/Visual/TestCaseEditorCompose.cs

@@ -0,0 +1,46 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using osu.Framework.Allocation;
+using osu.Game.Beatmaps;
+using osu.Game.Screens.Edit.Screens.Compose;
+
+namespace osu.Game.Tests.Visual
+{
+    public class TestCaseEditorCompose : OsuTestCase
+    {
+        private readonly Random random;
+        private readonly Compose compose;
+
+        public TestCaseEditorCompose()
+        {
+            random = new Random(1337);
+
+            Add(compose = new Compose());
+            AddStep("Next beatmap", nextBeatmap);
+        }
+
+        private OsuGameBase osuGame;
+        private BeatmapManager beatmaps;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuGameBase osuGame, BeatmapManager beatmaps)
+        {
+            this.osuGame = osuGame;
+            this.beatmaps = beatmaps;
+
+            compose.Beatmap.BindTo(osuGame.Beatmap);
+        }
+
+        private void nextBeatmap()
+        {
+            var sets = beatmaps.GetAllUsableBeatmapSets();
+            if (sets.Count == 0)
+                return;
+
+            var b = sets[random.Next(0, sets.Count)].Beatmaps[0];
+            osuGame.Beatmap.Value = beatmaps.GetWorkingBeatmap(b);
+        }
+    }
+}

osu.Game.Tests/Visual/TestCaseEditorComposeRadioButtons.cs

@@ -0,0 +1,41 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Collections.Generic;
+using osu.Framework.Graphics;
+using osu.Game.Screens.Edit.Screens.Compose.RadioButtons;
+
+namespace osu.Game.Tests.Visual
+{
+    public class TestCaseEditorComposeRadioButtons : OsuTestCase
+    {
+        public override IReadOnlyList<Type> RequiredTypes => new[] { typeof(DrawableRadioButton) };
+
+        public TestCaseEditorComposeRadioButtons()
+        {
+            RadioButtonCollection collection;
+            Add(collection = new RadioButtonCollection
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                Width = 150,
+                Items = new[]
+                {
+                    new RadioButton("Item 1", () => { }),
+                    new RadioButton("Item 2", () => { }),
+                    new RadioButton("Item 3", () => { }),
+                    new RadioButton("Item 4", () => { }),
+                    new RadioButton("Item 5", () => { })
+                }
+            });
+
+            for (int i = 0; i < collection.Items.Count; i++)
+            {
+                int l = i;
+                AddStep($"Select item {l + 1}", () => collection.Items[l].Select());
+                AddStep($"Deselect item {l + 1}", () => collection.Items[l].Deselect());
+            }
+        }
+    }
+}

osu.Game.Tests/osu.Game.Tests.csproj

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project DefaultTargets="Build" ToolsVersion="14.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="..\osu.Game.props" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -19,7 +20,6 @@
     <WarningLevel>4</WarningLevel>
     <ConsolePause>false</ConsolePause>
     <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
-    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <Optimize>true</Optimize>
@@ -45,9 +45,6 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\osu.licenseheader">
-      <Link>osu.licenseheader</Link>
-    </None>
     <None Include="app.config" />
     <None Include="packages.config" />
     <None Include="OpenTK.dll.config" />
@@ -106,6 +103,8 @@
     <Compile Include="Visual\TestCaseDrawableRoom.cs" />
     <Compile Include="Visual\TestCaseDrawings.cs" />
     <Compile Include="Visual\TestCaseEditor.cs" />
+    <Compile Include="Visual\TestCaseEditorCompose.cs" />
+    <Compile Include="Visual\TestCaseEditorComposeRadioButtons.cs" />
     <Compile Include="Visual\TestCaseEditorComposeTimeline.cs" />
     <Compile Include="Visual\TestCaseEditorMenuBar.cs" />
     <Compile Include="Visual\TestCaseEditorSummaryTimeline.cs" />

osu.Game.props

@@ -0,0 +1,13 @@
+<!-- Contains required properties for osu!framework projects. -->
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(SolutionDir)\packages\Microsoft.Net.Compilers.2.3.2\build\Microsoft.Net.Compilers.props" Condition="Exists('$(SolutionDir)\packages\Microsoft.Net.Compilers.2.3.2\build\Microsoft.Net.Compilers.props')" />
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup Label="C#">
+    <LangVersion>7</LangVersion>
+  </PropertyGroup>
+  <ItemGroup Label="License">
+    <None Include="..\osu.licenseheader">
+      <Link>osu.licenseheader</Link>
+    </None>
+  </ItemGroup>
+</Project>

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -32,7 +32,7 @@ namespace osu.Game.Beatmaps
             Mods.ValueChanged += mods => applyRateAdjustments();
 
             beatmap = new AsyncLazy<Beatmap>(populateBeatmap);
-            background = new AsyncLazy<Texture>(populateBackground);
+            background = new AsyncLazy<Texture>(populateBackground, b => b == null || !b.IsDisposed);
             track = new AsyncLazy<Track>(populateTrack);
             waveform = new AsyncLazy<Waveform>(populateWaveform);
             storyboard = new AsyncLazy<Storyboard>(populateStoryboard);
@@ -44,7 +44,7 @@ namespace osu.Game.Beatmaps
         protected virtual Waveform GetWaveform() => new Waveform();
         protected virtual Storyboard GetStoryboard() => new Storyboard();
 
-        public bool BeatmapLoaded => beatmap.IsValueCreated;
+        public bool BeatmapLoaded => beatmap.IsResultAvailable;
         public Beatmap Beatmap => beatmap.Value.Result;
         public async Task<Beatmap> GetBeatmapAsync() => await beatmap.Value;
 
@@ -60,14 +60,14 @@ namespace osu.Game.Beatmaps
             return b;
         }
 
-        public bool BackgroundLoaded => background.IsValueCreated;
+        public bool BackgroundLoaded => background.IsResultAvailable;
         public Texture Background => background.Value.Result;
         public async Task<Texture> GetBackgroundAsync() => await background.Value;
         private AsyncLazy<Texture> background;
 
         private Texture populateBackground() => GetBackground();
 
-        public bool TrackLoaded => track.IsValueCreated;
+        public bool TrackLoaded => track.IsResultAvailable;
         public Track Track => track.Value.Result;
         public async Task<Track> GetTrackAsync() => await track.Value;
         private AsyncLazy<Track> track;
@@ -80,7 +80,7 @@ namespace osu.Game.Beatmaps
             return t;
         }
 
-        public bool WaveformLoaded => waveform.IsValueCreated;
+        public bool WaveformLoaded => waveform.IsResultAvailable;
         public Waveform Waveform => waveform.Value.Result;
         public async Task<Waveform> GetWaveformAsync() => await waveform.Value;
         private readonly AsyncLazy<Waveform> waveform;
@@ -96,10 +96,10 @@ namespace osu.Game.Beatmaps
 
         public void TransferTo(WorkingBeatmap other)
         {
-            if (track.IsValueCreated && Track != null && BeatmapInfo.AudioEquals(other.BeatmapInfo))
+            if (track.IsResultAvailable && Track != null && BeatmapInfo.AudioEquals(other.BeatmapInfo))
                 other.track = track;
 
-            if (background.IsValueCreated && Background != null && BeatmapInfo.BackgroundEquals(other.BeatmapInfo))
+            if (background.IsResultAvailable && Background != null && BeatmapInfo.BackgroundEquals(other.BeatmapInfo))
                 other.background = background;
         }
 
@@ -110,14 +110,15 @@ namespace osu.Game.Beatmaps
             if (StoryboardLoaded) Storyboard?.Dispose();
         }
 
-        public void DisposeTrack()
+        /// <summary>
-        {
+        /// Eagerly dispose of the audio track associated with this <see cref="WorkingBeatmap"/> (if any).
-            if (TrackLoaded) Track?.Dispose();
+        /// Accessing track again will load a fresh instance.
-        }
+        /// </summary>
+        public void RecycleTrack() => track.Recycle();
 
         private void applyRateAdjustments(Track t = null)
         {
-            if (t == null && track.IsValueCreated) t = Track;
+            if (t == null && track.IsResultAvailable) t = Track;
             if (t == null) return;
 
             t.ResetSpeedAdjustments();
@@ -125,12 +126,65 @@ namespace osu.Game.Beatmaps
                 mod.ApplyToClock(t);
         }
 
-        public class AsyncLazy<T> : Lazy<Task<T>>
+        public class AsyncLazy<T>
         {
-            public AsyncLazy(Func<T> valueFactory)
+            private Lazy<Task<T>> lazy;
-                : base(() => Task.Run(valueFactory))
+            private readonly Func<T> valueFactory;
+            private readonly Func<T, bool> stillValidFunction;
+
+            private readonly object initLock = new object();
+
+            public AsyncLazy(Func<T> valueFactory, Func<T, bool> stillValidFunction = null)
             {
+                this.valueFactory = valueFactory;
+                this.stillValidFunction = stillValidFunction;
+
+                recreate();
             }
+
+            public void Recycle()
+            {
+                if (!IsResultAvailable) return;
+
+                (lazy.Value.Result as IDisposable)?.Dispose();
+                recreate();
+            }
+
+            public bool IsResultAvailable
+            {
+                get
+                {
+                    recreateIfInvalid();
+                    return lazy.Value.IsCompleted;
+                }
+            }
+
+            public Task<T> Value
+            {
+                get
+                {
+                    recreateIfInvalid();
+                    return lazy.Value;
+                }
+            }
+
+            private void recreateIfInvalid()
+            {
+                lock (initLock)
+                {
+                    if (!lazy.IsValueCreated || !lazy.Value.IsCompleted)
+                        // we have not yet been initialised or haven't run the task.
+                        return;
+
+                    if (stillValidFunction?.Invoke(lazy.Value.Result) ?? true)
+                        // we are still in a valid state.
+                        return;
+
+                    recreate();
+                }
+            }
+
+            private void recreate() => lazy = new Lazy<Task<T>>(() => Task.Run(valueFactory));
         }
     }
 }

osu.Game/OsuGameBase.cs

@@ -154,7 +154,7 @@ namespace osu.Game
                         Debug.Assert(lastBeatmap != null);
                         Debug.Assert(lastBeatmap.Track != null);
 
-                        lastBeatmap.DisposeTrack();
+                        lastBeatmap.RecycleTrack();
                     }
 
                     Audio.Track.AddItem(b.Track);

osu.Game/Overlays/Music/PlaylistList.cs

@@ -35,7 +35,11 @@ namespace osu.Game.Overlays.Music
             set { base.Padding = value; }
         }
 
-        public IEnumerable<BeatmapSetInfo> BeatmapSets { set { items.Sets = value; } }
+        public IEnumerable<BeatmapSetInfo> BeatmapSets
+        {
+            get { return items.Sets; }
+            set { items.Sets = value; }
+        }
 
         public BeatmapSetInfo FirstVisibleSet => items.FirstVisibleSet;
         public BeatmapSetInfo NextSet => items.NextSet;
@@ -48,7 +52,7 @@ namespace osu.Game.Overlays.Music
         }
 
         public void AddBeatmapSet(BeatmapSetInfo beatmapSet) => items.AddBeatmapSet(beatmapSet);
-        public bool RemoveBeatmapSet(BeatmapSetInfo beatmapSet) => items.RemoveBeatmapSet(beatmapSet);
+        public void RemoveBeatmapSet(BeatmapSetInfo beatmapSet) => items.RemoveBeatmapSet(beatmapSet);
 
         public void Filter(string searchTerm) => items.SearchTerm = searchTerm;
 
@@ -81,6 +85,7 @@ namespace osu.Game.Overlays.Music
 
             public IEnumerable<BeatmapSetInfo> Sets
             {
+                get { return items.Select(x => x.BeatmapSetInfo).ToList(); }
                 set
                 {
                     items.Clear();
@@ -103,12 +108,11 @@ namespace osu.Game.Overlays.Music
                 });
             }
 
-            public bool RemoveBeatmapSet(BeatmapSetInfo beatmapSet)
+            public void RemoveBeatmapSet(BeatmapSetInfo beatmapSet)
             {
                 var itemToRemove = items.FirstOrDefault(i => i.BeatmapSetInfo.ID == beatmapSet.ID);
-                if (itemToRemove == null)
+                if (itemToRemove != null)
-                    return false;
+                    items.Remove(itemToRemove);
-                return items.Remove(itemToRemove);
             }
 
             public BeatmapSetInfo SelectedSet
@@ -230,6 +234,7 @@ namespace osu.Game.Overlays.Music
             private class ItemSearchContainer : FillFlowContainer<PlaylistItem>, IHasFilterableChildren
             {
                 public IEnumerable<string> FilterTerms => new string[] { };
+
                 public bool MatchingFilter
                 {
                     set

osu.Game/Overlays/Music/PlaylistOverlay.cs

@@ -13,6 +13,7 @@ using osu.Game.Beatmaps;
 using osu.Game.Graphics;
 using OpenTK;
 using OpenTK.Graphics;
+using System.Threading;
 
 namespace osu.Game.Overlays.Music
 {
@@ -29,7 +30,7 @@ namespace osu.Game.Overlays.Music
 
         private readonly Bindable<WorkingBeatmap> beatmapBacking = new Bindable<WorkingBeatmap>();
 
-        public IEnumerable<BeatmapSetInfo> BeatmapSets;
+        public IEnumerable<BeatmapSetInfo> BeatmapSets => list.BeatmapSets;
 
         [BackgroundDependencyLoader]
         private void load(OsuGameBase game, BeatmapManager beatmaps, OsuColour colours)
@@ -74,11 +75,10 @@ namespace osu.Game.Overlays.Music
                 },
             };
 
-            beatmaps.BeatmapSetAdded += s => Schedule(() => list.AddBeatmapSet(s));
+            beatmaps.BeatmapSetAdded += list.AddBeatmapSet;
-            beatmaps.BeatmapSetRemoved += s => Schedule(() => list.RemoveBeatmapSet(s));
+            beatmaps.BeatmapSetRemoved += list.RemoveBeatmapSet;
-
-            list.BeatmapSets = BeatmapSets = beatmaps.GetAllUsableBeatmapSets();
 
+            list.BeatmapSets = beatmaps.GetAllUsableBeatmapSets();
 
             beatmapBacking.BindTo(game.Beatmap);
 
@@ -121,7 +121,7 @@ namespace osu.Game.Overlays.Music
                 return;
             }
 
-            playSpecified(set.Beatmaps[0]);
+            playSpecified(set.Beatmaps.First());
         }
 
         public void PlayPrevious()
@@ -130,7 +130,7 @@ namespace osu.Game.Overlays.Music
 
             if (playable != null)
             {
-                playSpecified(playable.Beatmaps[0]);
+                playSpecified(playable.Beatmaps.First());
                 list.SelectedSet = playable;
             }
         }
@@ -141,7 +141,7 @@ namespace osu.Game.Overlays.Music
 
             if (playable != null)
             {
-                playSpecified(playable.Beatmaps[0]);
+                playSpecified(playable.Beatmaps.First());
                 list.SelectedSet = playable;
             }
         }
@@ -149,7 +149,15 @@ namespace osu.Game.Overlays.Music
         private void playSpecified(BeatmapInfo info)
         {
             beatmapBacking.Value = beatmaps.GetWorkingBeatmap(info, beatmapBacking);
-            beatmapBacking.Value.Track.Start();
+
+            var track = beatmapBacking.Value.Track;
+
+            track.Restart();
+
+            // this is temporary until we have blocking (async.Wait()) audio component methods.
+            // then we can call RestartAsync().Wait() or the blocking version above.
+            while (!track.IsRunning)
+                Thread.Sleep(1);
         }
     }
 

osu.Game/Overlays/MusicController.cs

@@ -251,7 +251,7 @@ namespace osu.Game.Overlays
 
                 playButton.Icon = track.IsRunning ? FontAwesome.fa_pause_circle_o : FontAwesome.fa_play_circle_o;
 
-                if (track.HasCompleted && !track.Looping && !beatmapBacking.Disabled)
+                if (track.HasCompleted && !beatmapBacking.Disabled && playlist.BeatmapSets.Any())
                     next();
             }
             else

osu.Game/Rulesets/Edit/HitObjectComposer.cs

@@ -0,0 +1,109 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using OpenTK.Graphics;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Logging;
+using osu.Framework.Timing;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit.Tools;
+using osu.Game.Rulesets.UI;
+using osu.Game.Screens.Edit.Screens.Compose.RadioButtons;
+
+namespace osu.Game.Rulesets.Edit
+{
+    public abstract class HitObjectComposer : CompositeDrawable
+    {
+        private readonly Ruleset ruleset;
+
+        protected ICompositionTool CurrentTool { get; private set; }
+
+        protected HitObjectComposer(Ruleset ruleset)
+        {
+            this.ruleset = ruleset;
+
+            RelativeSizeAxes = Axes.Both;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuGameBase osuGame)
+        {
+            RulesetContainer rulesetContainer;
+            try
+            {
+                rulesetContainer = CreateRulesetContainer(ruleset, osuGame.Beatmap.Value);
+            }
+            catch (Exception e)
+            {
+                Logger.Log($"Could not load this beatmap sucessfully ({e})!", LoggingTarget.Runtime, LogLevel.Error);
+                return;
+            }
+
+            RadioButtonCollection toolboxCollection;
+            InternalChild = new GridContainer
+            {
+                RelativeSizeAxes = Axes.Both,
+                Content = new[]
+                {
+                    new Drawable[]
+                    {
+                        new FillFlowContainer
+                        {
+                            Name = "Sidebar",
+                            RelativeSizeAxes = Axes.Both,
+                            Padding = new MarginPadding { Right = 10 },
+                            Children = new Drawable[]
+                            {
+                                new ToolboxGroup { Child = toolboxCollection = new RadioButtonCollection { RelativeSizeAxes = Axes.X } }
+                            }
+                        },
+                        new Container
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Masking = true,
+                            BorderColour = Color4.White,
+                            BorderThickness = 2,
+                            Children = new Drawable[]
+                            {
+                                new Box
+                                {
+                                    RelativeSizeAxes = Axes.Both,
+                                    Alpha = 0,
+                                    AlwaysPresent = true,
+                                },
+                                rulesetContainer
+                            }
+                        }
+                    },
+                },
+                ColumnDimensions = new[]
+                {
+                    new Dimension(GridSizeMode.Absolute, 200),
+                }
+            };
+
+            rulesetContainer.Clock = new InterpolatingFramedClock((IAdjustableClock)osuGame.Beatmap.Value.Track ?? new StopwatchClock());
+
+            toolboxCollection.Items =
+                new[] { new RadioButton("Select", () => setCompositionTool(null)) }
+                .Concat(
+                    CompositionTools.Select(t => new RadioButton(t.Name, () => setCompositionTool(t)))
+                )
+                .ToList();
+
+            toolboxCollection.Items[0].Select();
+        }
+
+        private void setCompositionTool(ICompositionTool tool) => CurrentTool = tool;
+
+        protected virtual RulesetContainer CreateRulesetContainer(Ruleset ruleset, WorkingBeatmap beatmap) => ruleset.CreateRulesetContainerWith(beatmap, true);
+
+        protected abstract IReadOnlyList<ICompositionTool> CompositionTools { get; }
+    }
+}

osu.Game/Rulesets/Edit/ToolboxGroup.cs

@@ -0,0 +1,19 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Game.Screens.Play.ReplaySettings;
+
+namespace osu.Game.Rulesets.Edit
+{
+    public class ToolboxGroup : ReplayGroup
+    {
+        protected override string Title => "toolbox";
+
+        public ToolboxGroup()
+        {
+            RelativeSizeAxes = Axes.X;
+            Width = 1;
+        }
+    }
+}

osu.Game/Rulesets/Edit/Tools/HitObjectCompositionTool.cs

@@ -0,0 +1,13 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Game.Rulesets.Objects;
+
+namespace osu.Game.Rulesets.Edit.Tools
+{
+    public class HitObjectCompositionTool<T> : ICompositionTool
+        where T : HitObject
+    {
+        public string Name => typeof(T).Name;
+    }
+}

osu.Game/Rulesets/Edit/Tools/ICompositionTool.cs

@@ -0,0 +1,10 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+namespace osu.Game.Rulesets.Edit.Tools
+{
+    public interface ICompositionTool
+    {
+        string Name { get; }
+    }
+}

osu.Game/Rulesets/Ruleset.cs

@@ -9,6 +9,7 @@ using osu.Framework.Input.Bindings;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics;
 using osu.Game.Overlays.Settings;
+using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.UI;
@@ -52,6 +53,8 @@ namespace osu.Game.Rulesets
 
         public virtual PerformanceCalculator CreatePerformanceCalculator(Beatmap beatmap, Score score) => null;
 
+        public virtual HitObjectComposer CreateHitObjectComposer() => null;
+
         public virtual Drawable CreateIcon() => new SpriteIcon { Icon = FontAwesome.fa_question_circle };
 
         public abstract string Description { get; }

osu.Game/Rulesets/UI/RulesetContainer.cs

@@ -55,6 +55,11 @@ namespace osu.Game.Rulesets.UI
 
         public abstract IEnumerable<HitObject> Objects { get; }
 
+        /// <summary>
+        /// The playfield.
+        /// </summary>
+        public Playfield Playfield { get; protected set; }
+
         protected readonly Ruleset Ruleset;
 
         /// <summary>
@@ -135,11 +140,6 @@ namespace osu.Game.Rulesets.UI
 
         public override ScoreProcessor CreateScoreProcessor() => new ScoreProcessor<TObject>(this);
 
-        /// <summary>
-        /// The playfield.
-        /// </summary>
-        public Playfield Playfield { get; private set; }
-
         protected override Container<Drawable> Content => content;
         private Container content;
 

osu.Game/Screens/Edit/Components/Timelines/Summary/Parts/TimelinePart.cs

@@ -40,7 +40,8 @@ namespace osu.Game.Screens.Edit.Components.Timelines.Summary.Parts
                 return;
             }
 
-            timeline.RelativeChildSize = new Vector2((float)Math.Max(1, Beatmap.Value.Track.Length), 1);
+            // Todo: This should be handled more gracefully
+            timeline.RelativeChildSize = Beatmap.Value.Track.Length == double.PositiveInfinity ? Vector2.One : new Vector2((float)Math.Max(1, Beatmap.Value.Track.Length), 1);
         }
 
         protected void Add(Drawable visualisation) => timeline.Add(visualisation);

osu.Game/Screens/Edit/Screens/Compose/Compose.cs

@@ -6,22 +6,35 @@ using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
+using osu.Framework.Logging;
+using osu.Game.Beatmaps;
 using osu.Game.Screens.Edit.Screens.Compose.Timeline;
 
 namespace osu.Game.Screens.Edit.Screens.Compose
 {
     public class Compose : EditorScreen
     {
+        private const float vertical_margins = 10;
+        private const float horizontal_margins = 20;
+
+        private readonly Container composerContainer;
+
         public Compose()
         {
             ScrollableTimeline timeline;
-            Children = new[]
+            Children = new Drawable[]
+            {
+                new GridContainer
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Content = new[]
+                    {
+                        new Drawable[]
                         {
                             new Container
                             {
                                 Name = "Timeline",
-                    RelativeSizeAxes = Axes.X,
+                                RelativeSizeAxes = Axes.Both,
-                    Height = 110,
                                 Children = new Drawable[]
                                 {
                                     new Box
@@ -31,9 +44,9 @@ namespace osu.Game.Screens.Edit.Screens.Compose
                                     },
                                     new Container
                                     {
-                            Name = "Content",
+                                        Name = "Timeline content",
                                         RelativeSizeAxes = Axes.Both,
-                            Padding = new MarginPadding { Horizontal = 17, Vertical = 10 },
+                                        Padding = new MarginPadding { Horizontal = horizontal_margins, Vertical = vertical_margins },
                                         Children = new Drawable[]
                                         {
                                             new Container
@@ -46,9 +59,46 @@ namespace osu.Game.Screens.Edit.Screens.Compose
                                     }
                                 }
                             }
+                        },
+                        new Drawable[]
+                        {
+                            composerContainer = new Container
+                            {
+                                Name = "Composer content",
+                                RelativeSizeAxes = Axes.Both,
+                                Padding = new MarginPadding { Horizontal = horizontal_margins, Vertical = vertical_margins },
+                            }
+                        }
+                    },
+                    RowDimensions = new[] { new Dimension(GridSizeMode.Absolute, 110) }
+                },
             };
 
             timeline.Beatmap.BindTo(Beatmap);
+            Beatmap.ValueChanged += beatmapChanged;
+        }
+
+        private void beatmapChanged(WorkingBeatmap newBeatmap)
+        {
+            composerContainer.Clear();
+
+            var ruleset = newBeatmap.BeatmapInfo.Ruleset?.CreateInstance();
+            if (ruleset == null)
+            {
+                Logger.Log("Beatmap doesn't have a ruleset assigned.");
+                // ExitRequested?.Invoke();
+                return;
+            }
+
+            var composer = ruleset.CreateHitObjectComposer();
+            if (composer == null)
+            {
+                Logger.Log($"Ruleset {ruleset.Description} doesn't support hitobject composition.");
+                // ExitRequested?.Invoke();
+                return;
+            }
+
+            composerContainer.Child = composer;
         }
     }
 }

osu.Game/Screens/Edit/Screens/Compose/RadioButtons/DrawableRadioButton.cs

@@ -0,0 +1,123 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using OpenTK;
+using OpenTK.Graphics;
+using osu.Framework.Allocation;
+using osu.Framework.Extensions.Color4Extensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Graphics.UserInterface;
+
+namespace osu.Game.Screens.Edit.Screens.Compose.RadioButtons
+{
+    public class DrawableRadioButton : TriangleButton
+    {
+        /// <summary>
+        /// Invoked when this <see cref="DrawableRadioButton"/> has been selected.
+        /// </summary>
+        public Action<RadioButton> Selected;
+
+        private Color4 defaultBackgroundColour;
+        private Color4 defaultBubbleColour;
+        private Color4 selectedBackgroundColour;
+        private Color4 selectedBubbleColour;
+
+        private readonly Drawable bubble;
+        private readonly RadioButton button;
+
+        public DrawableRadioButton(RadioButton button)
+        {
+            this.button = button;
+
+            Text = button.Text;
+            Action = button.Action;
+
+            RelativeSizeAxes = Axes.X;
+
+            bubble = new CircularContainer
+            {
+                Anchor = Anchor.CentreLeft,
+                Origin = Anchor.CentreLeft,
+                RelativeSizeAxes = Axes.Both,
+                FillMode = FillMode.Fit,
+                Scale = new Vector2(0.5f),
+                X = 10,
+                Masking = true,
+                Blending = BlendingMode.Additive,
+                Child = new Box { RelativeSizeAxes = Axes.Both }
+            };
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            defaultBackgroundColour = colours.Gray3;
+            defaultBubbleColour = defaultBackgroundColour.Darken(0.5f);
+            selectedBackgroundColour = colours.BlueDark;
+            selectedBubbleColour = selectedBackgroundColour.Lighten(0.5f);
+
+            Triangles.Alpha = 0;
+
+            Content.EdgeEffect = new EdgeEffectParameters
+            {
+                Type = EdgeEffectType.Shadow,
+                Radius = 2,
+                Offset = new Vector2(0, 1),
+                Colour = Color4.Black.Opacity(0.5f)
+            };
+
+            Add(bubble);
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            button.Selected.ValueChanged += v =>
+            {
+                updateSelectionState();
+                if (v)
+                    Selected?.Invoke(button);
+            };
+
+            updateSelectionState();
+        }
+
+        private void updateSelectionState()
+        {
+            if (!IsLoaded)
+                return;
+
+            BackgroundColour = button.Selected ? selectedBackgroundColour : defaultBackgroundColour;
+            bubble.Colour = button.Selected ? selectedBubbleColour : defaultBubbleColour;
+        }
+
+        protected override bool OnClick(InputState state)
+        {
+            if (button.Selected)
+                return true;
+
+            if (!Enabled)
+                return true;
+
+            button.Selected.Value = true;
+
+            return base.OnClick(state);
+        }
+
+        protected override SpriteText CreateText() => new OsuSpriteText
+        {
+            Depth = -1,
+            Origin = Anchor.CentreLeft,
+            Anchor = Anchor.CentreLeft,
+            X = 40f
+        };
+    }
+}

osu.Game/Screens/Edit/Screens/Compose/RadioButtons/RadioButton.cs

@@ -0,0 +1,51 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System;
+using osu.Framework.Configuration;
+
+namespace osu.Game.Screens.Edit.Screens.Compose.RadioButtons
+{
+    public class RadioButton
+    {
+        /// <summary>
+        /// Whether this <see cref="RadioButton"/> is selected.
+        /// </summary>
+        /// <returns></returns>
+        public readonly BindableBool Selected;
+
+        /// <summary>
+        /// The text that should be displayed in this button.
+        /// </summary>
+        public string Text;
+
+        /// <summary>
+        /// The <see cref="Action"/> that should be invoked when this button is selected.
+        /// </summary>
+        public Action Action;
+
+        public RadioButton(string text, Action action)
+        {
+            Text = text;
+            Action = action;
+            Selected = new BindableBool();
+        }
+
+        public RadioButton(string text)
+            : this(text, null)
+        {
+            Text = text;
+            Action = null;
+        }
+
+        /// <summary>
+        /// Selects this <see cref="RadioButton"/>.
+        /// </summary>
+        public void Select() => Selected.Value = true;
+
+        /// <summary>
+        /// Deselects this <see cref="RadioButton"/>.
+        /// </summary>
+        public void Deselect() => Selected.Value = false;
+    }
+}

osu.Game/Screens/Edit/Screens/Compose/RadioButtons/RadioButtonCollection.cs

@@ -0,0 +1,61 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System.Collections.Generic;
+using OpenTK;
+using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+
+namespace osu.Game.Screens.Edit.Screens.Compose.RadioButtons
+{
+    public class RadioButtonCollection : CompositeDrawable
+    {
+        private IReadOnlyList<RadioButton> items;
+        public IReadOnlyList<RadioButton> Items
+        {
+            get { return items; }
+            set
+            {
+                if (ReferenceEquals(items, value))
+                    return;
+                items = value;
+
+                buttonContainer.Clear();
+                items.ForEach(addButton);
+            }
+        }
+
+        private readonly FlowContainer<DrawableRadioButton> buttonContainer;
+
+        public RadioButtonCollection()
+        {
+            AutoSizeAxes = Axes.Y;
+
+            InternalChild = buttonContainer = new FillFlowContainer<DrawableRadioButton>
+            {
+                RelativeSizeAxes = Axes.X,
+                AutoSizeAxes = Axes.Y,
+                Direction = FillDirection.Vertical,
+                Spacing = new Vector2(0, 5)
+            };
+        }
+
+        private RadioButton currentlySelected;
+        private void addButton(RadioButton button)
+        {
+            button.Selected.ValueChanged += v =>
+            {
+                if (v)
+                {
+                    currentlySelected?.Deselect();
+                    currentlySelected = button;
+                }
+                else
+                    currentlySelected = null;
+            };
+
+            buttonContainer.Add(new DrawableRadioButton(button));
+        }
+    }
+}

osu.Game/Screens/Loader.cs

@@ -1,8 +1,12 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
+using System.Collections.Generic;
+using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Shaders;
 using osu.Game.Screens.Menu;
 using OpenTK;
 using osu.Framework.Screens;
@@ -33,14 +37,28 @@ namespace osu.Game.Screens
             logo.FadeInFromZero(5000, Easing.OutQuint);
         }
 
+        private OsuScreen loadScreen;
+        private ShaderPrecompiler precompiler;
+
         protected override void OnEntering(Screen last)
         {
             base.OnEntering(last);
 
-            if (showDisclaimer)
+            LoadComponentAsync(precompiler = new ShaderPrecompiler(loadIfReady), Add);
-                LoadComponentAsync(new Disclaimer(), d => Push(d));
+            LoadComponentAsync(loadScreen = showDisclaimer ? (OsuScreen)new Disclaimer() : new Intro(), s => loadIfReady());
-            else
+        }
-                LoadComponentAsync(new Intro(), d => Push(d));
+
+        private void loadIfReady()
+        {
+            if (ChildScreen == loadScreen) return;
+
+            if (loadScreen.LoadState != LoadState.Ready)
+                return;
+
+            if (!precompiler.FinishedCompiling)
+                return;
+
+            Push(loadScreen);
         }
 
         protected override void LogoSuspending(OsuLogo logo)
@@ -54,5 +72,49 @@ namespace osu.Game.Screens
         {
             showDisclaimer = game.IsDeployedBuild;
         }
+
+        /// <summary>
+        /// Compiles a set of shaders before continuing. Attempts to draw some frames between compilation by limiting to one compile per draw frame.
+        /// </summary>
+        public class ShaderPrecompiler : Drawable
+        {
+            private readonly Action onLoaded;
+            private readonly List<Shader> loadTargets = new List<Shader>();
+
+            public bool FinishedCompiling { get; private set; }
+
+            public ShaderPrecompiler(Action onLoaded)
+            {
+                this.onLoaded = onLoaded;
+            }
+
+            [BackgroundDependencyLoader]
+            private void load(ShaderManager manager)
+            {
+                loadTargets.Add(manager.Load(VertexShaderDescriptor.TEXTURE_2, FragmentShaderDescriptor.TEXTURE_ROUNDED));
+                loadTargets.Add(manager.Load(VertexShaderDescriptor.TEXTURE_2, FragmentShaderDescriptor.BLUR));
+                loadTargets.Add(manager.Load(VertexShaderDescriptor.TEXTURE_2, FragmentShaderDescriptor.TEXTURE));
+
+                loadTargets.Add(manager.Load(@"CursorTrail", FragmentShaderDescriptor.TEXTURE));
+
+                loadTargets.Add(manager.Load(VertexShaderDescriptor.TEXTURE_3, FragmentShaderDescriptor.TEXTURE_ROUNDED));
+                loadTargets.Add(manager.Load(VertexShaderDescriptor.TEXTURE_3, FragmentShaderDescriptor.TEXTURE));
+            }
+
+            private Shader currentLoadTarget;
+
+            protected override void Update()
+            {
+                base.Update();
+
+                // if our target is null we are done.
+                if (loadTargets.All(s => s.Loaded))
+                {
+                    FinishedCompiling = true;
+                    Expire();
+                    onLoaded?.Invoke();
+                }
+            }
+        }
     }
 }

osu.Game/Screens/OsuScreen.cs

@@ -13,6 +13,8 @@ using osu.Framework.Audio;
 using osu.Framework.Graphics;
 using osu.Game.Rulesets;
 using osu.Game.Screens.Menu;
+using osu.Framework.Input;
+using OpenTK.Input;
 
 namespace osu.Game.Screens
 {
@@ -73,6 +75,20 @@ namespace osu.Game.Screens
             sampleExit = audio.Sample.Get(@"UI/screen-back");
         }
 
+        protected override bool OnKeyDown(InputState state, KeyDownEventArgs args)
+        {
+            if (args.Repeat || !IsCurrentScreen) return false;
+
+            switch (args.Key)
+            {
+                case Key.Escape:
+                    Exit();
+                    return true;
+            }
+
+            return base.OnKeyDown(state, args);
+        }
+
         protected override void OnResuming(Screen last)
         {
             base.OnResuming(last);

osu.Game/Screens/Select/BeatmapCarousel.cs

@@ -45,7 +45,7 @@ namespace osu.Game.Screens.Select
 
                 Task.Run(() =>
                 {
-                    newGroups = value.Select(createGroup).ToList();
+                    newGroups = value.Select(createGroup).Where(g => g != null).ToList();
                     criteria.Filter(newGroups);
                 }).ContinueWith(t =>
                 {
@@ -124,16 +124,19 @@ namespace osu.Game.Screens.Select
             // todo: this method should be smarter as to not recreate panels that haven't changed, etc.
             var group = groups.Find(b => b.BeatmapSet.ID == set.ID);
 
-            if (group == null)
-                return;
-
             int i = groups.IndexOf(group);
+            if (i >= 0)
                 groups.RemoveAt(i);
 
             var newGroup = createGroup(set);
 
             if (newGroup != null)
+            {
+                if (i >= 0)
                     groups.Insert(i, newGroup);
+                else
+                    groups.Add(newGroup);
+            }
 
             bool hadSelection = selectedGroup == group;
 

osu.Game/Screens/Select/SongSelect.cs

@@ -263,10 +263,7 @@ namespace osu.Game.Screens.Select
             beatmapNoDebounce = beatmap;
 
             if (beatmap == null)
-            {
-                if (!Beatmap.IsDefault)
                 performLoad();
-            }
             else
             {
                 if (beatmap.BeatmapSetInfoID == beatmapNoDebounce?.BeatmapSetInfoID)

osu.Game/osu.Game.csproj

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="14.0">
+  <Import Project="..\osu.Game.props" />
   <PropertyGroup>
     <ProjectGuid>{2A66DD92-ADB1-4994-89E2-C94E04ACDA0D}</ProjectGuid>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -61,7 +62,6 @@
     <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
     <Commandlineparameters>
     </Commandlineparameters>
-    <LangVersion>6</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>none</DebugType>
@@ -195,9 +195,6 @@
     </Reference>
   </ItemGroup>
   <ItemGroup>
-    <None Include="..\osu.licenseheader">
-      <Link>osu.licenseheader</Link>
-    </None>
     <None Include="app.config" />
     <None Include="OpenTK.dll.config" />
     <None Include="osu!.res" />
@@ -285,7 +282,7 @@
       <DependentUpon>20171025071459_AddMissingIndexRules.cs</DependentUpon>
     </Compile>
     <Compile Include="Migrations\20171119065731_AddBeatmapOnlineIDUniqueConstraint.cs" />
-    <Compile Include="Migrations\20171119065731_AddBeatmapOnlineIDUniqueConstraint.designer.cs">
+    <Compile Include="Migrations\20171119065731_AddBeatmapOnlineIDUniqueConstraint.Designer.cs">
       <DependentUpon>20171119065731_AddBeatmapOnlineIDUniqueConstraint.cs</DependentUpon>
     </Compile>
     <Compile Include="Migrations\OsuDbContextModelSnapshot.cs" />
@@ -308,7 +305,6 @@
     <Compile Include="Screens\Edit\Components\PlaybackControl.cs" />
     <Compile Include="Screens\Edit\Components\TimeInfoContainer.cs" />
     <Compile Include="Rulesets\Mods\IApplicableToScoreProcessor.cs" />
-    <Compile Include="Screens\Edit\Screens\Compose\Timeline\BeatmapWaveformGraph.cs" />
     <Compile Include="Beatmaps\Drawables\DifficultyColouredContainer.cs" />
     <Compile Include="Beatmaps\Drawables\DifficultyIcon.cs" />
     <Compile Include="Beatmaps\Drawables\Panel.cs" />
@@ -318,6 +314,10 @@
     <Compile Include="Beatmaps\IO\ArchiveReader.cs" />
     <Compile Include="Beatmaps\IO\LegacyFilesystemReader.cs" />
     <Compile Include="Online\API\Requests\GetUserScoresRequest.cs" />
+    <Compile Include="Screens\Edit\Screens\Compose\RadioButtons\DrawableRadioButton.cs" />
+    <Compile Include="Screens\Edit\Screens\Compose\RadioButtons\RadioButton.cs" />
+    <Compile Include="Screens\Edit\Screens\Compose\RadioButtons\RadioButtonCollection.cs" />
+    <Compile Include="Screens\Edit\Screens\Compose\Timeline\BeatmapWaveformGraph.cs" />
     <Compile Include="Screens\Edit\Screens\Compose\Timeline\TimelineButton.cs" />
     <Compile Include="Screens\Play\BreaksOverlay\ArrowsOverlay.cs" />
     <Compile Include="Screens\Play\BreaksOverlay\BlurredIcon.cs" />
@@ -561,6 +561,10 @@
     <Compile Include="Overlays\UserProfileOverlay.cs" />
     <Compile Include="Overlays\WaveOverlayContainer.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Rulesets\Edit\Tools\HitObjectCompositionTool.cs" />
+    <Compile Include="Rulesets\Edit\Tools\ICompositionTool.cs" />
+    <Compile Include="Rulesets\Edit\HitObjectComposer.cs" />
+    <Compile Include="Rulesets\Edit\ToolboxGroup.cs" />
     <Compile Include="Rulesets\Judgements\DrawableJudgement.cs" />
     <Compile Include="Rulesets\Judgements\Judgement.cs" />
     <Compile Include="Rulesets\Mods\IApplicableToClock.cs" />

osu.sln.DotSettings

@@ -34,6 +34,7 @@
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=ConvertToAutoProperty/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=ConvertToConstant_002ELocal/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=ConvertToLambdaExpression/@EntryIndexedValue">WARNING</s:String>
+	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=ConvertToLocalFunction/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=ConvertToStaticClass/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=DoubleNegationOperator/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=EmptyGeneralCatchClause/@EntryIndexedValue">DO_NOT_SHOW</s:String>
@@ -44,13 +45,16 @@
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=ForCanBeConvertedToForeach/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=InconsistentNaming/@EntryIndexedValue">ERROR</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=InheritdocConsiderUsage/@EntryIndexedValue">HINT</s:String>
+	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=InlineOutVariableDeclaration/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=InvertIf/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=InvokeAsExtensionMethod/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=JoinDeclarationAndInitializer/@EntryIndexedValue">WARNING</s:String>
+	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=JoinNullCheckWithUsage/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=MemberCanBeMadeStatic_002ELocal/@EntryIndexedValue">DO_NOT_SHOW</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=MemberCanBePrivate_002EGlobal/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=MemberCanBePrivate_002ELocal/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=MemberCanBeProtected_002EGlobal/@EntryIndexedValue">HINT</s:String>
+	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=MergeCastWithTypeCheck/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=MergeConditionalExpression/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=MergeSequentialChecks/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=MethodSupportsCancellation/@EntryIndexedValue">WARNING</s:String>
@@ -149,6 +153,7 @@
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=UseNameofExpression/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=UseNullPropagation/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=UseObjectOrCollectionInitializer/@EntryIndexedValue">WARNING</s:String>
+	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=UsePatternMatching/@EntryIndexedValue">HINT</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=UseStringInterpolation/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=VariableCanBeMadeConst/@EntryIndexedValue">WARNING</s:String>
 	<s:String x:Key="/Default/CodeInspection/Highlighting/InspectionSeverities/=VirtualMemberCallInConstructor/@EntryIndexedValue">HINT</s:String>