Merge remote-tracking branch 'origin/master' into editor-timeline-rework

osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs

@@ -84,10 +84,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
                 yield break;
 
             foreach (ManiaHitObject obj in objects)
-            {
-                obj.HitWindows = original.HitWindows;
                 yield return obj;
-            }
         }
 
         private readonly List<double> prevNoteTimes = new List<double>(max_notes_for_density);

osu.Game.Rulesets.Mania/Difficulty/ManiaDifficultyCalculator.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Difficulty;
 using osu.Game.Rulesets.Mania.Beatmaps;
@@ -49,18 +50,17 @@ namespace osu.Game.Rulesets.Mania.Difficulty
 
             int columnCount = (Beatmap as ManiaBeatmap)?.TotalColumns ?? 7;
 
-            foreach (var hitObject in Beatmap.HitObjects)
-                difficultyHitObjects.Add(new ManiaHitObjectDifficulty((ManiaHitObject)hitObject, columnCount));
-
             // Sort DifficultyHitObjects by StartTime of the HitObjects - just to make sure.
-            difficultyHitObjects.Sort((a, b) => a.BaseHitObject.StartTime.CompareTo(b.BaseHitObject.StartTime));
+            // Note: Stable sort is done so that the ordering of hitobjects with equal start times doesn't change
+            difficultyHitObjects.AddRange(Beatmap.HitObjects.Select(h => new ManiaHitObjectDifficulty((ManiaHitObject)h, columnCount)).OrderBy(h => h.BaseHitObject.StartTime));
 
             if (!calculateStrainValues())
                 return 0;
 
             double starRating = calculateDifficulty() * star_scaling_factor;
 
-            categoryDifficulty?.Add("Strain", starRating);
+            if (categoryDifficulty != null)
+                categoryDifficulty["Strain"] = starRating;
 
             return starRating;
         }

osu.Game.Rulesets.Mania/Difficulty/ManiaPerformanceCalculator.cs

@@ -0,0 +1,126 @@
+// Copyright (c) 2007-2018 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.Difficulty;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
+
+namespace osu.Game.Rulesets.Mania.Difficulty
+{
+    public class ManiaPerformanceCalculator : PerformanceCalculator
+    {
+        private Mod[] mods;
+
+        // Score after being scaled by non-difficulty-increasing mods
+        private double scaledScore;
+
+        private int countPerfect;
+        private int countGreat;
+        private int countGood;
+        private int countOk;
+        private int countMeh;
+        private int countMiss;
+
+        public ManiaPerformanceCalculator(Ruleset ruleset, IBeatmap beatmap, Score score)
+            : base(ruleset, beatmap, score)
+        {
+        }
+
+        public override double Calculate(Dictionary<string, double> categoryDifficulty = null)
+        {
+            mods = Score.Mods;
+            scaledScore = Score.TotalScore;
+            countPerfect = Convert.ToInt32(Score.Statistics[HitResult.Perfect]);
+            countGreat = Convert.ToInt32(Score.Statistics[HitResult.Great]);
+            countGood = Convert.ToInt32(Score.Statistics[HitResult.Good]);
+            countOk = Convert.ToInt32(Score.Statistics[HitResult.Ok]);
+            countMeh = Convert.ToInt32(Score.Statistics[HitResult.Meh]);
+            countMiss = Convert.ToInt32(Score.Statistics[HitResult.Miss]);
+
+            if (mods.Any(m => !m.Ranked))
+                return 0;
+
+            IEnumerable<Mod> scoreIncreaseMods = Ruleset.GetModsFor(ModType.DifficultyIncrease);
+
+            double scoreMultiplier = 1.0;
+            foreach (var m in mods.Where(m => !scoreIncreaseMods.Contains(m)))
+                scoreMultiplier *= m.ScoreMultiplier;
+
+            // Scale score up, so it's comparable to other keymods
+            scaledScore *= 1.0 / scoreMultiplier;
+
+            // Arbitrary initial value for scaling pp in order to standardize distributions across game modes.
+            // The specific number has no intrinsic meaning and can be adjusted as needed.
+            double multiplier = 0.8;
+
+            if (mods.Any(m => m is ModNoFail))
+                multiplier *= 0.9;
+            if (mods.Any(m => m is ModEasy))
+                multiplier *= 0.5;
+
+            double strainValue = computeStrainValue();
+            double accValue = computeAccuracyValue(strainValue);
+            double totalValue =
+                Math.Pow(
+                    Math.Pow(strainValue, 1.1) +
+                    Math.Pow(accValue, 1.1), 1.0 / 1.1
+                ) * multiplier;
+
+            if (categoryDifficulty != null)
+            {
+                categoryDifficulty["Strain"] = strainValue;
+                categoryDifficulty["Accuracy"] = accValue;
+            }
+
+            return totalValue;
+        }
+
+        private double computeStrainValue()
+        {
+            // Obtain strain difficulty
+            double strainValue = Math.Pow(5 * Math.Max(1, Attributes["Strain"] / 0.2) - 4.0, 2.2) / 135.0;
+
+            // Longer maps are worth more
+            strainValue *= 1.0 + 0.1 * Math.Min(1.0, totalHits / 1500.0);
+
+            if (scaledScore <= 500000)
+                strainValue = 0;
+            else if (scaledScore <= 600000)
+                strainValue *= (scaledScore - 500000) / 100000 * 0.3;
+            else if (scaledScore <= 700000)
+                strainValue *= 0.3 + (scaledScore - 600000) / 100000 * 0.25;
+            else if (scaledScore <= 800000)
+                strainValue *= 0.55 + (scaledScore - 700000) / 100000 * 0.20;
+            else if (scaledScore <= 900000)
+                strainValue *= 0.75 + (scaledScore - 800000) / 100000 * 0.15;
+            else
+                strainValue *= 0.90 + (scaledScore - 900000) / 100000 * 0.1;
+
+            return strainValue;
+        }
+
+        private double computeAccuracyValue(double strainValue)
+        {
+            double hitWindowGreat = (Beatmap.HitObjects.First().HitWindows.Great / 2 - 0.5) / TimeRate;
+            if (hitWindowGreat <= 0)
+                return 0;
+
+            // Lots of arbitrary values from testing.
+            // Considering to use derivation from perfect accuracy in a probabilistic manner - assume normal distribution
+            double accuracyValue = Math.Max(0.0, 0.2 - (hitWindowGreat - 34) * 0.006667)
+                                       * strainValue
+                                       * Math.Pow(Math.Max(0.0, scaledScore - 960000) / 40000, 1.1);
+
+            // Bonus for many hitcircles - it's harder to keep good accuracy up for longer
+            // accuracyValue *= Math.Min(1.15, Math.Pow(totalHits / 1500.0, 0.3));
+
+            return accuracyValue;
+        }
+
+        private double totalHits => countPerfect + countOk + countGreat + countGood + countMeh + countMiss;
+    }
+}

osu.Game.Rulesets.Mania/Judgements/HoldNoteJudgement.cs

@@ -0,0 +1,13 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Game.Rulesets.Scoring;
+
+namespace osu.Game.Rulesets.Mania.Judgements
+{
+    public class HoldNoteJudgement : ManiaJudgement
+    {
+        public override bool AffectsCombo => false;
+        protected override int NumericResultFor(HitResult result) => 0;
+    }
+}

osu.Game.Rulesets.Mania/ManiaRuleset.cs

@@ -18,6 +18,7 @@ using osu.Game.Beatmaps.Legacy;
 using osu.Game.Rulesets.Difficulty;
 using osu.Game.Rulesets.Mania.Beatmaps;
 using osu.Game.Rulesets.Mania.Difficulty;
+using osu.Game.Rulesets.Scoring;
 
 namespace osu.Game.Rulesets.Mania
 {
@@ -25,6 +26,7 @@ namespace osu.Game.Rulesets.Mania
     {
         public override RulesetContainer CreateRulesetContainerWith(WorkingBeatmap beatmap) => new ManiaRulesetContainer(this, beatmap);
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new ManiaBeatmapConverter(beatmap);
+        public override PerformanceCalculator CreatePerformanceCalculator(IBeatmap beatmap, Score score) => new ManiaPerformanceCalculator(this, beatmap, score);
 
         public override IEnumerable<Mod> ConvertLegacyMods(LegacyMods mods)
         {

osu.Game.Rulesets.Mania/Objects/Drawables/DrawableHoldNote.cs

@@ -99,6 +99,19 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
 
         protected override void UpdateState(ArmedState state)
         {
+            switch (state)
+            {
+                case ArmedState.Hit:
+                    // Good enough for now, we just want them to have a lifetime end
+                    this.Delay(2000).Expire();
+                    break;
+            }
+        }
+
+        protected override void CheckForJudgements(bool userTriggered, double timeOffset)
+        {
+            if (tail.AllJudged)
+                AddJudgement(new HoldNoteJudgement { Result = HitResult.Perfect });
         }
 
         protected override void Update()
@@ -191,6 +204,13 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
         /// </summary>
         private class DrawableTailNote : DrawableNote
         {
+            /// <summary>
+            /// Lenience of release hit windows. This is to make cases where the hold note release
+            /// is timed alongside presses of other hit objects less awkward.
+            /// Todo: This shouldn't exist for non-LegacyBeatmapDecoder beatmaps
+            /// </summary>
+            private const double release_window_lenience = 1.5;
+
             private readonly DrawableHoldNote holdNote;
 
             public DrawableTailNote(DrawableHoldNote holdNote, ManiaAction action)
@@ -203,6 +223,9 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
 
             protected override void CheckForJudgements(bool userTriggered, double timeOffset)
             {
+                // Factor in the release lenience
+                timeOffset /= release_window_lenience;
+
                 if (!userTriggered)
                 {
                     if (!HitObject.HitWindows.CanBeHit(timeOffset))

osu.Game.Rulesets.Mania/Objects/HoldNote.cs

@@ -55,7 +55,7 @@ namespace osu.Game.Rulesets.Mania.Objects
         /// <summary>
         /// The tail note of the hold.
         /// </summary>
-        public readonly Note Tail = new TailNote();
+        public readonly Note Tail = new Note();
 
         /// <summary>
         /// The time between ticks of this hold.
@@ -94,25 +94,5 @@ namespace osu.Game.Rulesets.Mania.Objects
                 });
             }
         }
-
-        /// <summary>
-        /// The tail of the hold note.
-        /// </summary>
-        private class TailNote : Note
-        {
-            /// <summary>
-            /// Lenience of release hit windows. This is to make cases where the hold note release
-            /// is timed alongside presses of other hit objects less awkward.
-            /// Todo: This shouldn't exist for non-LegacyBeatmapDecoder beatmaps
-            /// </summary>
-            private const double release_window_lenience = 1.5;
-
-            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
-            {
-                base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
-
-                HitWindows *= release_window_lenience;
-            }
-        }
     }
 }

osu.Game.Rulesets.Mania/Objects/ManiaHitObject.cs

@@ -1,8 +1,6 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
-using osu.Game.Beatmaps;
-using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Rulesets.Mania.Objects.Types;
 using osu.Game.Rulesets.Objects;
 
@@ -12,12 +10,6 @@ namespace osu.Game.Rulesets.Mania.Objects
     {
         public virtual int Column { get; set; }
 
-        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+        protected override HitWindows CreateHitWindows() => new ManiaHitWindows();
-        {
-            base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
-
-            HitWindows.AllowsPerfect = true;
-            HitWindows.AllowsOk = true;
-        }
     }
 }

osu.Game.Rulesets.Mania/Objects/ManiaHitWindows.cs

@@ -3,11 +3,12 @@
 
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Scoring;
 
-namespace osu.Game.Rulesets.Objects.Legacy.Mania
+namespace osu.Game.Rulesets.Mania.Objects
 {
-    public class ConvertHitWindows : HitWindows
+    public class ManiaHitWindows : HitWindows
     {
         private static readonly IReadOnlyDictionary<HitResult, (double od0, double od5, double od10)> base_ranges = new Dictionary<HitResult, (double, double, double)>
         {
@@ -21,6 +22,9 @@ namespace osu.Game.Rulesets.Objects.Legacy.Mania
 
         public override void SetDifficulty(double difficulty)
         {
+            AllowsPerfect = true;
+            AllowsOk = true;
+
             Perfect = BeatmapDifficulty.DifficultyRange(difficulty, base_ranges[HitResult.Perfect]);
             Great = BeatmapDifficulty.DifficultyRange(difficulty, base_ranges[HitResult.Great]);
             Good = BeatmapDifficulty.DifficultyRange(difficulty, base_ranges[HitResult.Good]);

osu.Game.Rulesets.Osu/Beatmaps/OsuBeatmapConverter.cs

@@ -40,8 +40,7 @@ namespace osu.Game.Rulesets.Osu.Beatmaps
                     RepeatSamples = curveData.RepeatSamples,
                     RepeatCount = curveData.RepeatCount,
                     Position = positionData?.Position ?? Vector2.Zero,
-                    NewCombo = comboData?.NewCombo ?? false,
+                    NewCombo = comboData?.NewCombo ?? false
-                    HitWindows = original.HitWindows
                 };
             }
             else if (endTimeData != null)
@@ -51,8 +50,7 @@ namespace osu.Game.Rulesets.Osu.Beatmaps
                     StartTime = original.StartTime,
                     Samples = original.Samples,
                     EndTime = endTimeData.EndTime,
-                    Position = positionData?.Position ?? OsuPlayfield.BASE_SIZE / 2,
+                    Position = positionData?.Position ?? OsuPlayfield.BASE_SIZE / 2
-                    HitWindows = original.HitWindows
                 };
             }
             else
@@ -62,8 +60,7 @@ namespace osu.Game.Rulesets.Osu.Beatmaps
                     StartTime = original.StartTime,
                     Samples = original.Samples,
                     Position = positionData?.Position ?? Vector2.Zero,
-                    NewCombo = comboData?.NewCombo ?? false,
+                    NewCombo = comboData?.NewCombo ?? false
-                    HitWindows = original.HitWindows
                 };
             }
         }

osu.Game.Rulesets.Osu/Difficulty/OsuPerformanceCalculator.cs

@@ -11,7 +11,7 @@ using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Rulesets.Scoring;
 
-namespace osu.Game.Rulesets.Osu.Scoring
+namespace osu.Game.Rulesets.Osu.Difficulty
 {
     public class OsuPerformanceCalculator : PerformanceCalculator
     {

osu.Game.Rulesets.Osu/Objects/OsuHitObject.cs

@@ -71,5 +71,7 @@ namespace osu.Game.Rulesets.Osu.Objects
         }
 
         public virtual void OffsetPosition(Vector2 offset) => Position += offset;
+
+        protected override HitWindows CreateHitWindows() => new OsuHitWindows();
     }
 }

osu.Game.Rulesets.Osu/Objects/OsuHitWindows.cs

@@ -3,11 +3,12 @@
 
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Scoring;
 
-namespace osu.Game.Rulesets.Objects.Legacy.Osu
+namespace osu.Game.Rulesets.Osu.Objects
 {
-    public class ConvertHitWindows : HitWindows
+    public class OsuHitWindows : HitWindows
     {
         private static readonly IReadOnlyDictionary<HitResult, (double od0, double od5, double od10)> base_ranges = new Dictionary<HitResult, (double, double, double)>
         {

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -12,7 +12,6 @@ using osu.Framework.Graphics;
 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;
 using osu.Game.Rulesets.Osu.Replays;

osu.Game.Rulesets.Taiko.Tests/TaikoBeatmapConversionTest.cs

@@ -17,8 +17,8 @@ namespace osu.Game.Rulesets.Taiko.Tests
         protected override string ResourceAssembly => "osu.Game.Rulesets.Taiko";
 
         [NonParallelizable]
-        [TestCase("basic", false), Ignore("See: https://github.com/ppy/osu/issues/2152")]
+        [TestCase("basic")]
-        [TestCase("slider-generating-drumroll", false)]
+        [TestCase("slider-generating-drumroll")]
         public new void Test(string name)
         {
             base.Test(name);

osu.Game.Rulesets.Taiko/Beatmaps/TaikoBeatmapConverter.cs

@@ -8,7 +8,6 @@ using osu.Game.Rulesets.Taiko.Objects;
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using osu.Game.IO.Serialization;
 using osu.Game.Audio;
 using osu.Game.Beatmaps.ControlPoints;
 
@@ -51,8 +50,9 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
         protected override Beatmap<TaikoHitObject> ConvertBeatmap(IBeatmap original)
         {
             // Rewrite the beatmap info to add the slider velocity multiplier
-            BeatmapInfo info = original.BeatmapInfo.DeepClone();
+            original.BeatmapInfo = original.BeatmapInfo.Clone();
-            info.BaseDifficulty.SliderMultiplier *= legacy_velocity_multiplier;
+            original.BeatmapInfo.BaseDifficulty = original.BeatmapInfo.BaseDifficulty.Clone();
+            original.BeatmapInfo.BaseDifficulty.SliderMultiplier *= legacy_velocity_multiplier;
 
             Beatmap<TaikoHitObject> converted = base.ConvertBeatmap(original);
 
@@ -98,12 +98,12 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
                 double distance = distanceData.Distance * spans * legacy_velocity_multiplier;
 
                 // The velocity of the taiko hit object - calculated as the velocity of a drum roll
-                double taikoVelocity = taiko_base_distance * beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier * legacy_velocity_multiplier / speedAdjustedBeatLength;
+                double taikoVelocity = taiko_base_distance * beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier / speedAdjustedBeatLength;
                 // The duration of the taiko hit object
                 double taikoDuration = distance / taikoVelocity;
 
                 // The velocity of the osu! hit object - calculated as the velocity of a slider
-                double osuVelocity = osu_base_scoring_distance * beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier * legacy_velocity_multiplier / speedAdjustedBeatLength;
+                double osuVelocity = osu_base_scoring_distance * beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier / speedAdjustedBeatLength;
                 // The duration of the osu! hit object
                 double osuDuration = distance / osuVelocity;
 
@@ -132,8 +132,7 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
                             {
                                 StartTime = j,
                                 Samples = currentSamples,
-                                IsStrong = strong,
+                                IsStrong = strong
-                                HitWindows = obj.HitWindows
                             };
                         }
                         else
@@ -142,8 +141,7 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
                             {
                                 StartTime = j,
                                 Samples = currentSamples,
-                                IsStrong = strong,
+                                IsStrong = strong
-                                HitWindows = obj.HitWindows
                             };
                         }
 
@@ -158,8 +156,7 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
                         Samples = obj.Samples,
                         IsStrong = strong,
                         Duration = taikoDuration,
-                        TickRate = beatmap.BeatmapInfo.BaseDifficulty.SliderTickRate == 3 ? 3 : 4,
+                        TickRate = beatmap.BeatmapInfo.BaseDifficulty.SliderTickRate == 3 ? 3 : 4
-                        HitWindows = obj.HitWindows
                     };
                 }
             }
@@ -173,8 +170,7 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
                     Samples = obj.Samples,
                     IsStrong = strong,
                     Duration = endTimeData.Duration,
-                    RequiredHits = (int)Math.Max(1, endTimeData.Duration / 1000 * hitMultiplier),
+                    RequiredHits = (int)Math.Max(1, endTimeData.Duration / 1000 * hitMultiplier)
-                    HitWindows = obj.HitWindows
                 };
             }
             else
@@ -187,8 +183,7 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
                     {
                         StartTime = obj.StartTime,
                         Samples = obj.Samples,
-                        IsStrong = strong,
+                        IsStrong = strong
-                        HitWindows = obj.HitWindows
                     };
                 }
                 else
@@ -197,8 +192,7 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
                     {
                         StartTime = obj.StartTime,
                         Samples = obj.Samples,
-                        IsStrong = strong,
+                        IsStrong = strong
-                        HitWindows = obj.HitWindows
                     };
                 }
             }

osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Difficulty;
+using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Taiko.Objects;
 
 namespace osu.Game.Rulesets.Taiko.Difficulty
@@ -35,6 +36,11 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
         {
         }
 
+        public TaikoDifficultyCalculator(IBeatmap beatmap, Mod[] mods)
+            : base(beatmap, mods)
+        {
+        }
+
         public override double Calculate(Dictionary<string, double> categoryDifficulty = null)
         {
             // Fill our custom DifficultyHitObject class, that carries additional information
@@ -51,10 +57,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
             double starRating = calculateDifficulty() * star_scaling_factor;
 
             if (categoryDifficulty != null)
-            {
+                categoryDifficulty["Strain"] = starRating;
-                categoryDifficulty.Add("Strain", starRating);
-                categoryDifficulty.Add("Hit window 300", 35 /*HitObjectManager.HitWindow300*/ / TimeRate);
-            }
 
             return starRating;
         }

osu.Game.Rulesets.Taiko/Difficulty/TaikoPerformanceCalculator.cs

@@ -0,0 +1,111 @@
+// Copyright (c) 2007-2018 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.Difficulty;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Rulesets.Taiko.Objects;
+
+namespace osu.Game.Rulesets.Taiko.Difficulty
+{
+    public class TaikoPerformanceCalculator : PerformanceCalculator
+    {
+        private readonly int beatmapMaxCombo;
+
+        private Mod[] mods;
+        private int countGreat;
+        private int countGood;
+        private int countMeh;
+        private int countMiss;
+
+        public TaikoPerformanceCalculator(Ruleset ruleset, IBeatmap beatmap, Score score)
+            : base(ruleset, beatmap, score)
+        {
+            beatmapMaxCombo = beatmap.HitObjects.Count(h => h is Hit);
+        }
+
+        public override double Calculate(Dictionary<string, double> categoryDifficulty = null)
+        {
+            mods = Score.Mods;
+            countGreat = Convert.ToInt32(Score.Statistics[HitResult.Great]);
+            countGood = Convert.ToInt32(Score.Statistics[HitResult.Good]);
+            countMeh = Convert.ToInt32(Score.Statistics[HitResult.Meh]);
+            countMiss = Convert.ToInt32(Score.Statistics[HitResult.Miss]);
+
+            // Don't count scores made with supposedly unranked mods
+            if (mods.Any(m => !m.Ranked))
+                return 0;
+
+            // Custom multipliers for NoFail and SpunOut.
+            double multiplier = 1.1; // This is being adjusted to keep the final pp value scaled around what it used to be when changing things
+
+            if (mods.Any(m => m is ModNoFail))
+                multiplier *= 0.90;
+
+            if (mods.Any(m => m is ModHidden))
+                multiplier *= 1.10;
+
+            double strainValue = computeStrainValue();
+            double accuracyValue = computeAccuracyValue();
+            double totalValue =
+                Math.Pow(
+                    Math.Pow(strainValue, 1.1) +
+                    Math.Pow(accuracyValue, 1.1), 1.0 / 1.1
+                ) * multiplier;
+
+            if (categoryDifficulty != null)
+            {
+                categoryDifficulty["Strain"] = strainValue;
+                categoryDifficulty["Accuracy"] = accuracyValue;
+            }
+
+            return totalValue;
+        }
+
+        private double computeStrainValue()
+        {
+            double strainValue = Math.Pow(5.0 * Math.Max(1.0, Attributes["Strain"] / 0.0075) - 4.0, 2.0) / 100000.0;
+
+            // Longer maps are worth more
+            double lengthBonus = 1 + 0.1f * Math.Min(1.0, totalHits / 1500.0);
+            strainValue *= lengthBonus;
+
+            // Penalize misses exponentially. This mainly fixes tag4 maps and the likes until a per-hitobject solution is available
+            strainValue *= Math.Pow(0.985, countMiss);
+
+            // Combo scaling
+            if (beatmapMaxCombo > 0)
+                strainValue *= Math.Min(Math.Pow(Score.MaxCombo, 0.5) / Math.Pow(beatmapMaxCombo, 0.5), 1.0);
+
+            if (mods.Any(m => m is ModHidden))
+                strainValue *= 1.025;
+
+            if (mods.Any(m => m is ModFlashlight))
+                // Apply length bonus again if flashlight is on simply because it becomes a lot harder on longer maps.
+                strainValue *= 1.05 * lengthBonus;
+
+            // Scale the speed value with accuracy _slightly_
+            return strainValue * Score.Accuracy;
+        }
+
+        private double computeAccuracyValue()
+        {
+            double hitWindowGreat = (Beatmap.HitObjects.First().HitWindows.Great / 2 - 0.5) / TimeRate;
+            if (hitWindowGreat <= 0)
+                return 0;
+
+            // Lots of arbitrary values from testing.
+            // Considering to use derivation from perfect accuracy in a probabilistic manner - assume normal distribution
+            double accValue = Math.Pow(150.0 / hitWindowGreat, 1.1) * Math.Pow(Score.Accuracy, 15) * 22.0;
+
+            // Bonus for many hitcircles - it's harder to keep good accuracy up for longer
+            return accValue * Math.Min(1.15, Math.Pow(totalHits / 1500.0, 0.3));
+        }
+
+        private int totalHits => countGreat + countGood + countMeh + countMiss;
+    }
+}

osu.Game.Rulesets.Taiko/Objects/TaikoHitObject.cs

@@ -27,5 +27,7 @@ namespace osu.Game.Rulesets.Taiko.Objects
         /// Strong hit objects give more points for hitting the hit object with both keys.
         /// </summary>
         public bool IsStrong;
+
+        protected override HitWindows CreateHitWindows() => new TaikoHitWindows();
     }
 }

osu.Game.Rulesets.Taiko/Objects/TaikoHitWindows.cs

@@ -3,11 +3,12 @@
 
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Scoring;
 
-namespace osu.Game.Rulesets.Objects.Legacy.Taiko
+namespace osu.Game.Rulesets.Taiko.Objects
 {
-    public class ConvertHitWindows : HitWindows
+    public class TaikoHitWindows : HitWindows
     {
         private static readonly IReadOnlyDictionary<HitResult, (double od0, double od5, double od10)> base_ranges = new Dictionary<HitResult, (double, double, double)>
         {

osu.Game.Rulesets.Taiko/TaikoRuleset.cs

@@ -14,6 +14,7 @@ using osu.Game.Rulesets.Replays.Types;
 using osu.Game.Rulesets.Taiko.Replays;
 using osu.Game.Beatmaps.Legacy;
 using osu.Game.Rulesets.Difficulty;
+using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.Taiko.Beatmaps;
 using osu.Game.Rulesets.Taiko.Difficulty;
 
@@ -144,7 +145,9 @@ namespace osu.Game.Rulesets.Taiko
 
         public override Drawable CreateIcon() => new SpriteIcon { Icon = FontAwesome.fa_osu_taiko_o };
 
-        public override DifficultyCalculator CreateDifficultyCalculator(IBeatmap beatmap, Mod[] mods = null) => new TaikoDifficultyCalculator(beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IBeatmap beatmap, Mod[] mods = null) => new TaikoDifficultyCalculator(beatmap, mods);
+
+        public override PerformanceCalculator CreatePerformanceCalculator(IBeatmap beatmap, Score score) => new TaikoPerformanceCalculator(this, beatmap, score);
 
         public override int? LegacyID => 1;
 

osu.Game.Tests/Visual/TestCaseDrawableRoom.cs

@@ -6,6 +6,7 @@ using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Beatmaps;
+using osu.Game.Graphics.UserInterface;
 using osu.Game.Online.Multiplayer;
 using osu.Game.Rulesets;
 using osu.Game.Screens.Multi.Components;
@@ -111,6 +112,7 @@ namespace osu.Game.Tests.Visual
                 }
             });
 
+            AddStep(@"select", () => first.State = SelectionState.Selected);
             AddStep(@"change title", () => first.Room.Name.Value = @"I Changed Name");
             AddStep(@"change host", () => first.Room.Host.Value = new User { Username = @"DrabWeb", Id = 6946022, Country = new Country { FlagName = @"CA" } });
             AddStep(@"change status", () => first.Room.Status.Value = new RoomStatusPlaying());
@@ -121,6 +123,7 @@ namespace osu.Game.Tests.Visual
                 new User { Statistics = new UserStatistics { Ranks = new UserStatistics.UserRanks { Global = 1254 } } },
                 new User { Statistics = new UserStatistics { Ranks = new UserStatistics.UserRanks { Global = 123189 } } },
             });
+            AddStep(@"deselect", () => first.State = SelectionState.NotSelected);
         }
 
         [BackgroundDependencyLoader]

osu.Game.Tests/Visual/TestCaseMultiHeader.cs

@@ -0,0 +1,27 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using NUnit.Framework;
+using osu.Framework.Graphics;
+using osu.Game.Screens.Multi;
+using osu.Game.Screens.Multi.Screens;
+
+namespace osu.Game.Tests.Visual
+{
+    [TestFixture]
+    public class TestCaseMultiHeader : OsuTestCase
+    {
+        public TestCaseMultiHeader()
+        {
+            Lobby lobby;
+            Children = new Drawable[]
+            {
+                lobby = new Lobby
+                {
+                    Padding = new MarginPadding { Top = Header.HEIGHT },
+                },
+                new Header(lobby),
+            };
+        }
+    }
+}

osu.Game.Tests/Visual/TestCaseMultiScreen.cs

@@ -0,0 +1,21 @@
+// Copyright (c) 2007-2018 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.Screens.Multi;
+
+namespace osu.Game.Tests.Visual
+{
+    [TestFixture]
+    public class TestCaseMultiScreen : OsuTestCase
+    {
+        public TestCaseMultiScreen()
+        {
+            Multiplayer multi = new Multiplayer();
+
+            AddStep(@"show", () => Add(multi));
+            AddWaitStep(5);
+            AddStep(@"exit", multi.Exit);
+        }
+    }
+}

osu.Game.Tests/Visual/TestCaseRoomInspector.cs

@@ -21,7 +21,7 @@ namespace osu.Game.Tests.Visual
         {
             base.LoadComplete();
 
-            var room = new Room
+            Room room = new Room
             {
                 Name = { Value = @"My Awesome Room" },
                 Host = { Value = new User { Username = @"flyte", Id = 3103765, Country = new Country { FlagName = @"JP" } } },
@@ -71,9 +71,13 @@ namespace osu.Game.Tests.Visual
             {
                 Anchor = Anchor.Centre,
                 Origin = Anchor.Centre,
-                Room = room,
+                RelativeSizeAxes = Axes.Both,
+                Width = 0.5f,
             });
 
+            AddStep(@"set room", () => inspector.Room = room);
+            AddStep(@"null room", () => inspector.Room = null);
+            AddStep(@"set room", () => inspector.Room = room);
             AddStep(@"change title", () => room.Name.Value = @"A Better Room Than The Above");
             AddStep(@"change host", () => room.Host.Value = new User { Username = @"DrabWeb", Id = 6946022, Country = new Country { FlagName = @"CA" } });
             AddStep(@"change status", () => room.Status.Value = new RoomStatusPlaying());
@@ -88,7 +92,7 @@ namespace osu.Game.Tests.Visual
 
             AddStep(@"change room", () =>
             {
-                var newRoom = new Room
+                Room newRoom = new Room
                 {
                     Name = { Value = @"My New, Better Than Ever Room" },
                     Host = { Value = new User { Username = @"Angelsim", Id = 1777162, Country = new Country { FlagName = @"KR" } } },

osu.Game.Tests/Visual/TestCaseScreenBreadcrumbControl.cs

@@ -0,0 +1,145 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Screens;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Screens;
+using OpenTK;
+
+namespace osu.Game.Tests.Visual
+{
+    [TestFixture]
+    public class TestCaseScreenBreadcrumbControl : OsuTestCase
+    {
+        private readonly ScreenBreadcrumbControl breadcrumbs;
+        private Screen currentScreen, changedScreen;
+
+        public TestCaseScreenBreadcrumbControl()
+        {
+            TestScreen startScreen;
+            OsuSpriteText titleText;
+
+            Children = new Drawable[]
+            {
+                currentScreen = startScreen = new TestScreenOne(),
+                new FillFlowContainer
+                {
+                    RelativeSizeAxes = Axes.X,
+                    AutoSizeAxes = Axes.Y,
+                    Direction = FillDirection.Vertical,
+                    Spacing = new Vector2(10),
+                    Children = new Drawable[]
+                    {
+                        breadcrumbs = new ScreenBreadcrumbControl(startScreen)
+                        {
+                            RelativeSizeAxes = Axes.X,
+                        },
+                        titleText = new OsuSpriteText(),
+                    },
+                },
+            };
+
+            breadcrumbs.Current.ValueChanged += s =>
+            {
+                titleText.Text = $"Changed to {s.ToString()}";
+                changedScreen = s;
+            };
+
+            breadcrumbs.Current.TriggerChange();
+
+            assertCurrent();
+            pushNext();
+            assertCurrent();
+            pushNext();
+            assertCurrent();
+
+            AddStep(@"make start current", () =>
+            {
+                startScreen.MakeCurrent();
+                currentScreen = startScreen;
+            });
+
+            assertCurrent();
+            pushNext();
+            AddAssert(@"only 2 items", () => breadcrumbs.Items.Count() == 2);
+            AddStep(@"exit current", () => changedScreen.Exit());
+            AddAssert(@"current screen is first", () => startScreen == changedScreen);
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            breadcrumbs.StripColour = colours.Blue;
+        }
+
+        private void pushNext() => AddStep(@"push next screen", () => currentScreen = ((TestScreen)currentScreen).PushNext());
+        private void assertCurrent() => AddAssert(@"changedScreen correct", () => currentScreen == changedScreen);
+
+        private abstract class TestScreen : OsuScreen
+        {
+            protected abstract string Title { get; }
+            protected abstract string NextTitle { get; }
+            protected abstract TestScreen CreateNextScreen();
+
+            public override string ToString() => Title;
+
+            public TestScreen PushNext()
+            {
+                TestScreen screen = CreateNextScreen();
+                Push(screen);
+
+                return screen;
+            }
+
+            protected TestScreen()
+            {
+                Child = new FillFlowContainer
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    AutoSizeAxes = Axes.Both,
+                    Direction = FillDirection.Vertical,
+                    Spacing = new Vector2(10),
+                    Children = new Drawable[]
+                    {
+                        new OsuSpriteText
+                        {
+                            Anchor = Anchor.TopCentre,
+                            Origin = Anchor.TopCentre,
+                            Text = Title,
+                        },
+                        new TriangleButton
+                        {
+                            Anchor = Anchor.TopCentre,
+                            Origin = Anchor.TopCentre,
+                            Width = 100,
+                            Text = $"Push {NextTitle}",
+                            Action = () => PushNext(),
+                        },
+                    },
+                };
+            }
+        }
+
+        private class TestScreenOne : TestScreen
+        {
+            protected override string Title => @"Screen One";
+            protected override string NextTitle => @"Two";
+            protected override TestScreen CreateNextScreen() => new TestScreenTwo();
+        }
+
+        private class TestScreenTwo : TestScreen
+        {
+            protected override string Title => @"Screen Two";
+            protected override string NextTitle => @"One";
+            protected override TestScreen CreateNextScreen() => new TestScreenOne();
+        }
+    }
+}

osu.Game/Beatmaps/Beatmap.cs

@@ -6,7 +6,6 @@ using osu.Game.Rulesets.Objects;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Beatmaps.ControlPoints;
-using osu.Game.IO.Serialization;
 using Newtonsoft.Json;
 using osu.Game.IO.Serialization.Converters;
 
@@ -55,17 +54,11 @@ namespace osu.Game.Beatmaps
 
         IBeatmap IBeatmap.Clone() => Clone();
 
-        public Beatmap<T> Clone()
+        public Beatmap<T> Clone() => (Beatmap<T>)MemberwiseClone();
-        {
-            var newInstance = (Beatmap<T>)MemberwiseClone();
-            newInstance.BeatmapInfo = BeatmapInfo.DeepClone();
-
-            return newInstance;
-        }
     }
 
     public class Beatmap : Beatmap<HitObject>
     {
-        public Beatmap Clone() => (Beatmap)base.Clone();
+        public new Beatmap Clone() => (Beatmap)base.Clone();
     }
 }

osu.Game/Beatmaps/BeatmapConverter.cs

@@ -53,8 +53,6 @@ namespace osu.Game.Beatmaps
         {
             var beatmap = CreateBeatmap();
 
-            // todo: this *must* share logic (or directly use) Beatmap<T>'s constructor.
-            // right now this isn't easily possible due to generic entanglement.
             beatmap.BeatmapInfo = original.BeatmapInfo;
             beatmap.ControlPointInfo = original.ControlPointInfo;
             beatmap.HitObjects = original.HitObjects.SelectMany(h => convert(h, original)).ToList();

osu.Game/Beatmaps/BeatmapDifficulty.cs

@@ -32,6 +32,11 @@ namespace osu.Game.Beatmaps
         public double SliderMultiplier { get; set; } = 1;
         public double SliderTickRate { get; set; } = 1;
 
+        /// <summary>
+        /// Returns a shallow-clone of this <see cref="BeatmapDifficulty"/>.
+        /// </summary>
+        public BeatmapDifficulty Clone() => (BeatmapDifficulty)MemberwiseClone();
+
         /// <summary>
         /// Maps a difficulty value [0, 10] to a two-piece linear range of values.
         /// </summary>

osu.Game/Beatmaps/BeatmapInfo.cs

@@ -143,5 +143,10 @@ namespace osu.Game.Beatmaps
         public bool BackgroundEquals(BeatmapInfo other) => other != null && BeatmapSet != null && other.BeatmapSet != null &&
                                                       BeatmapSet.Hash == other.BeatmapSet.Hash &&
                                                       (Metadata ?? BeatmapSet.Metadata).BackgroundFile == (other.Metadata ?? other.BeatmapSet.Metadata).BackgroundFile;
+
+        /// <summary>
+        /// Returns a shallow-clone of this <see cref="BeatmapInfo"/>.
+        /// </summary>
+        public BeatmapInfo Clone() => (BeatmapInfo)MemberwiseClone();
     }
 }

osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs

@@ -54,9 +54,11 @@ namespace osu.Game.Beatmaps.Formats
 
             base.ParseStreamInto(stream, beatmap);
 
-            // objects may be out of order *only* if a user has manually edited an .osu file.
+            // Objects may be out of order *only* if a user has manually edited an .osu file.
-            // unfortunately there are ranked maps in this state (example: https://osu.ppy.sh/s/594828).
+            // Unfortunately there are ranked maps in this state (example: https://osu.ppy.sh/s/594828).
-            this.beatmap.HitObjects.Sort((x, y) => x.StartTime.CompareTo(y.StartTime));
+            // OrderBy is used to guarantee that the parsing order of hitobjects with equal start times is maintained (stably-sorted)
+            // The parsing order of hitobjects matters in mania difficulty calculation
+            this.beatmap.HitObjects = this.beatmap.HitObjects.OrderBy(h => h.StartTime).ToList();
 
             foreach (var hitObject in this.beatmap.HitObjects)
                 hitObject.ApplyDefaults(this.beatmap.ControlPointInfo, this.beatmap.BeatmapInfo.BaseDifficulty);

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -107,8 +107,14 @@ namespace osu.Game.Beatmaps
             IBeatmap converted = converter.Convert();
 
             // Apply difficulty mods
-            foreach (var mod in Mods.Value.OfType<IApplicableToDifficulty>())
+            if (Mods.Value.Any(m => m is IApplicableToDifficulty))
-                mod.ApplyToDifficulty(converted.BeatmapInfo.BaseDifficulty);
+            {
+                converted.BeatmapInfo = converted.BeatmapInfo.Clone();
+                converted.BeatmapInfo.BaseDifficulty = converted.BeatmapInfo.BaseDifficulty.Clone();
+
+                foreach (var mod in Mods.Value.OfType<IApplicableToDifficulty>())
+                    mod.ApplyToDifficulty(converted.BeatmapInfo.BaseDifficulty);
+            }
 
             // Post-process
             rulesetInstance.CreateBeatmapProcessor(converted)?.PostProcess();

osu.Game/Graphics/Containers/OsuFocusedOverlayContainer.cs

@@ -7,6 +7,7 @@ using osu.Framework.Audio.Sample;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Input;
 using OpenTK;
+using osu.Framework.Configuration;
 
 namespace osu.Game.Graphics.Containers
 {
@@ -15,9 +16,14 @@ namespace osu.Game.Graphics.Containers
         private SampleChannel samplePopIn;
         private SampleChannel samplePopOut;
 
-        [BackgroundDependencyLoader]
+        private readonly BindableBool allowOpeningOverlays = new BindableBool(true);
-        private void load(AudioManager audio)
+
+        [BackgroundDependencyLoader(true)]
+        private void load(OsuGame osuGame, AudioManager audio)
         {
+            if (osuGame != null)
+                allowOpeningOverlays.BindTo(osuGame.AllowOpeningOverlays);
+
             samplePopIn = audio.Sample.Get(@"UI/overlay-pop-in");
             samplePopOut = audio.Sample.Get(@"UI/overlay-pop-out");
 
@@ -46,15 +52,20 @@ namespace osu.Game.Graphics.Containers
 
         private void onStateChanged(Visibility visibility)
         {
-            switch (visibility)
+            if (allowOpeningOverlays)
             {
-                case Visibility.Visible:
+                switch (visibility)
-                    samplePopIn?.Play();
+                {
-                    break;
+                    case Visibility.Visible:
-                case Visibility.Hidden:
+                        samplePopIn?.Play();
-                    samplePopOut?.Play();
+                        break;
-                    break;
+                    case Visibility.Hidden:
+                        samplePopOut?.Play();
+                        break;
+                }
             }
+            else
+                State = Visibility.Hidden;
         }
     }
 }

osu.Game/Graphics/UserInterface/ScreenBreadcrumbControl.cs

@@ -0,0 +1,54 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using System.Linq;
+using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Framework.Screens;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    /// <summary>
+    /// A <see cref="BreadcrumbControl"/> which follows the active screen (and allows navigation) in a <see cref="Screen"/> stack.
+    /// </summary>
+    public class ScreenBreadcrumbControl : BreadcrumbControl<Screen>
+    {
+        private Screen last;
+
+        public ScreenBreadcrumbControl(Screen initialScreen)
+        {
+            Current.ValueChanged += newScreen =>
+            {
+                if (last != newScreen && !newScreen.IsCurrentScreen)
+                    newScreen.MakeCurrent();
+            };
+
+            onPushed(initialScreen);
+        }
+
+        private void screenChanged(Screen newScreen)
+        {
+            if (newScreen == null) return;
+
+            if (last != null)
+            {
+                last.Exited -= screenChanged;
+                last.ModePushed -= onPushed;
+            }
+
+            last = newScreen;
+
+            newScreen.Exited += screenChanged;
+            newScreen.ModePushed += onPushed;
+
+            Current.Value = newScreen;
+        }
+
+        private void onPushed(Screen screen)
+        {
+            Items.ToList().SkipWhile(i => i != Current.Value).Skip(1).ForEach(RemoveItem);
+            AddItem(screen);
+
+            screenChanged(screen);
+        }
+    }
+}

osu.Game/Graphics/UserInterface/SelectionState.cs

@@ -0,0 +1,11 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+namespace osu.Game.Graphics.UserInterface
+{
+    public enum SelectionState
+    {
+        NotSelected,
+        Selected
+    }
+}

osu.Game/IO/Serialization/IJsonSerializable.cs

@@ -18,8 +18,6 @@ namespace osu.Game.IO.Serialization
 
         public static void DeserializeInto<T>(this string objString, T target) => JsonConvert.PopulateObject(objString, target, CreateGlobalSettings());
 
-        public static T DeepClone<T>(this T obj) where T : IJsonSerializable => Deserialize<T>(Serialize(obj));
-
         /// <summary>
         /// Creates the default <see cref="JsonSerializerSettings"/> that should be used for all <see cref="IJsonSerializable"/>s.
         /// </summary>

osu.Game/Input/Bindings/GlobalActionContainer.cs

@@ -37,6 +37,9 @@ namespace osu.Game.Input.Bindings
             new KeyBinding(InputKey.Down, GlobalAction.DecreaseVolume),
             new KeyBinding(InputKey.MouseWheelDown, GlobalAction.DecreaseVolume),
             new KeyBinding(InputKey.F4, GlobalAction.ToggleMute),
+
+            new KeyBinding(InputKey.Escape, GlobalAction.Back),
+            new KeyBinding(InputKey.MouseButton1, GlobalAction.Back)
         };
 
         public IEnumerable<KeyBinding> InGameKeyBindings => new[]
@@ -80,5 +83,8 @@ namespace osu.Game.Input.Bindings
         TakeScreenshot,
         [Description("Toggle gameplay mouse buttons")]
         ToggleGameplayMouseButtons,
+
+        [Description("Go back")]
+        Back
     }
 }

osu.Game/OsuGame.cs

@@ -77,7 +77,8 @@ namespace osu.Game
 
         public float ToolbarOffset => Toolbar.Position.Y + Toolbar.DrawHeight;
 
-        public readonly BindableBool ShowOverlays = new BindableBool();
+        public readonly BindableBool HideOverlaysOnEnter = new BindableBool();
+        public readonly BindableBool AllowOpeningOverlays = new BindableBool(true);
 
         private OsuScreen screenStack;
 
@@ -367,12 +368,12 @@ namespace osu.Game
             settings.StateChanged += _ => updateScreenOffset();
             notifications.StateChanged += _ => updateScreenOffset();
 
-            notifications.Enabled.BindTo(ShowOverlays);
+            notifications.Enabled.BindTo(AllowOpeningOverlays);
 
-            ShowOverlays.ValueChanged += show =>
+            HideOverlaysOnEnter.ValueChanged += hide =>
             {
                 //central game screen change logic.
-                if (!show)
+                if (hide)
                 {
                     hideAllOverlays();
                     musicController.State = Visibility.Hidden;

osu.Game/Overlays/MainSettings.cs

@@ -6,9 +6,11 @@ using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Input;
+using osu.Framework.Input.Bindings;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Input.Bindings;
 using osu.Game.Overlays.Settings;
 using osu.Game.Overlays.Settings.Sections;
 using osu.Game.Screens.Ranking;
@@ -96,7 +98,7 @@ namespace osu.Game.Overlays
             });
         }
 
-        private class BackButton : OsuClickableContainer
+        private class BackButton : OsuClickableContainer, IKeyBindingHandler<GlobalAction>
         {
             private AspectContainer aspect;
 
@@ -146,6 +148,20 @@ namespace osu.Game.Overlays
                 aspect.ScaleTo(1, 1000, Easing.OutElastic);
                 return base.OnMouseUp(state, args);
             }
+
+            public bool OnPressed(GlobalAction action)
+            {
+                switch (action)
+                {
+                    case GlobalAction.Back:
+                        TriggerOnClick();
+                        return true;
+                }
+
+                return false;
+            }
+
+            public bool OnReleased(GlobalAction action) => false;
         }
     }
 }

osu.Game/Overlays/Toolbar/ToolbarModeSelector.cs

@@ -6,7 +6,9 @@ using osu.Framework.Allocation;
 using osu.Framework.Caching;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Framework.Input;
 using OpenTK;
+using OpenTK.Input;
 using OpenTK.Graphics;
 using osu.Framework.Configuration;
 using osu.Framework.Graphics.Shapes;
@@ -22,6 +24,7 @@ namespace osu.Game.Overlays.Toolbar
         private readonly Drawable modeButtonLine;
         private ToolbarModeButton activeButton;
 
+        private RulesetStore rulesets;
         private readonly Bindable<RulesetInfo> ruleset = new Bindable<RulesetInfo>();
 
         public ToolbarModeSelector()
@@ -67,26 +70,42 @@ namespace osu.Game.Overlays.Toolbar
         [BackgroundDependencyLoader(true)]
         private void load(RulesetStore rulesets, OsuGame game)
         {
+            this.rulesets = rulesets;
             foreach (var r in rulesets.AvailableRulesets)
             {
                 modeButtons.Add(new ToolbarModeButton
                 {
                     Ruleset = r,
-                    Action = delegate
+                    Action = delegate { ruleset.Value = r; }
-                    {
-                        ruleset.Value = r;
-                    }
                 });
             }
 
             ruleset.ValueChanged += rulesetChanged;
             ruleset.DisabledChanged += disabledChanged;
+
             if (game != null)
                 ruleset.BindTo(game.Ruleset);
             else
                 ruleset.Value = rulesets.AvailableRulesets.FirstOrDefault();
         }
 
+        protected override bool OnKeyDown(InputState state, KeyDownEventArgs args)
+        {
+            base.OnKeyDown(state, args);
+
+            if (state.Keyboard.ControlPressed && !args.Repeat && args.Key >= Key.Number1 && args.Key <= Key.Number9)
+            {
+                int requested = args.Key - Key.Number1;
+
+                RulesetInfo found = rulesets.AvailableRulesets.Skip(requested).FirstOrDefault();
+                if (found != null)
+                    ruleset.Value = found;
+                return true;
+            }
+
+            return false;
+        }
+
         public override bool HandleKeyboardInput => !ruleset.Disabled && base.HandleKeyboardInput;
         public override bool HandleMouseInput => !ruleset.Disabled && base.HandleMouseInput;
 

osu.Game/Rulesets/Difficulty/PerformanceCalculator.cs

@@ -16,6 +16,7 @@ namespace osu.Game.Rulesets.Difficulty
         private readonly Dictionary<string, double> attributes = new Dictionary<string, double>();
         protected IDictionary<string, double> Attributes => attributes;
 
+        protected readonly Ruleset Ruleset;
         protected readonly IBeatmap Beatmap;
         protected readonly Score Score;
 
@@ -23,9 +24,9 @@ namespace osu.Game.Rulesets.Difficulty
 
         protected PerformanceCalculator(Ruleset ruleset, IBeatmap beatmap, Score score)
         {
-            Score = score;
+            Ruleset = ruleset;
-
             Beatmap = beatmap;
+            Score = score;
 
             var diffCalc = ruleset.CreateDifficultyCalculator(beatmap, score.Mods);
             diffCalc.Calculate(attributes);

osu.Game/Rulesets/Edit/HitObjectMask.cs

@@ -6,6 +6,7 @@ using osu.Framework;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Primitives;
 using osu.Framework.Input;
+using osu.Game.Graphics.UserInterface;
 using osu.Game.Rulesets.Objects.Drawables;
 using OpenTK;
 
@@ -137,10 +138,4 @@ namespace osu.Game.Rulesets.Edit
         /// </summary>
         public virtual Quad SelectionQuad => ScreenSpaceDrawQuad;
     }
-
-    public enum SelectionState
-    {
-        NotSelected,
-        Selected
-    }
 }

osu.Game/Rulesets/Objects/HitObject.cs

@@ -1,6 +1,7 @@
 // Copyright (c) 2007-2018 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 Newtonsoft.Json;
 using osu.Framework.Extensions.IEnumerableExtensions;
@@ -56,10 +57,10 @@ namespace osu.Game.Rulesets.Objects
         /// </summary>
         public HitWindows HitWindows { get; set; }
 
-        private readonly SortedList<HitObject> nestedHitObjects = new SortedList<HitObject>((h1, h2) => h1.StartTime.CompareTo(h2.StartTime));
+        private readonly Lazy<SortedList<HitObject>> nestedHitObjects = new Lazy<SortedList<HitObject>>(() => new SortedList<HitObject>((h1, h2) => h1.StartTime.CompareTo(h2.StartTime)));
 
         [JsonIgnore]
-        public IReadOnlyList<HitObject> NestedHitObjects => nestedHitObjects;
+        public IReadOnlyList<HitObject> NestedHitObjects => nestedHitObjects.Value;
 
         /// <summary>
         /// Applies default values to this HitObject.
@@ -70,13 +71,19 @@ namespace osu.Game.Rulesets.Objects
         {
             ApplyDefaultsToSelf(controlPointInfo, difficulty);
 
-            nestedHitObjects.Clear();
+            if (nestedHitObjects.IsValueCreated)
+                nestedHitObjects.Value.Clear();
+
             CreateNestedHitObjects();
-            nestedHitObjects.ForEach(h =>
+
+            if (nestedHitObjects.IsValueCreated)
             {
-                h.HitWindows = HitWindows;
+                nestedHitObjects.Value.ForEach(h =>
-                h.ApplyDefaults(controlPointInfo, difficulty);
+                {
-            });
+                    h.HitWindows = HitWindows;
+                    h.ApplyDefaults(controlPointInfo, difficulty);
+                });
+            }
         }
 
         protected virtual void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
@@ -96,7 +103,7 @@ namespace osu.Game.Rulesets.Objects
         {
         }
 
-        protected void AddNested(HitObject hitObject) => nestedHitObjects.Add(hitObject);
+        protected void AddNested(HitObject hitObject) => nestedHitObjects.Value.Add(hitObject);
 
         /// <summary>
         /// Creates the <see cref="HitWindows"/> for this <see cref="HitObject"/>.

osu.Game/Rulesets/Objects/HitWindows.cs

@@ -135,39 +135,5 @@ namespace osu.Game.Rulesets.Objects
         /// <param name="timeOffset">The time offset.</param>
         /// <returns>Whether the <see cref="HitObject"/> can be hit at any point in the future from this time offset.</returns>
         public bool CanBeHit(double timeOffset) => timeOffset <= HalfWindowFor(HitResult.Meh);
-
-        /// <summary>
-        /// Multiplies all hit windows by a value.
-        /// </summary>
-        /// <param name="windows">The hit windows to multiply.</param>
-        /// <param name="value">The value to multiply each hit window by.</param>
-        public static HitWindows operator *(HitWindows windows, double value)
-        {
-            windows.Perfect *= value;
-            windows.Great *= value;
-            windows.Good *= value;
-            windows.Ok *= value;
-            windows.Meh *= value;
-            windows.Miss *= value;
-
-            return windows;
-        }
-
-        /// <summary>
-        /// Divides all hit windows by a value.
-        /// </summary>
-        /// <param name="windows">The hit windows to divide.</param>
-        /// <param name="value">The value to divide each hit window by.</param>
-        public static HitWindows operator /(HitWindows windows, double value)
-        {
-            windows.Perfect /= value;
-            windows.Great /= value;
-            windows.Good /= value;
-            windows.Ok /= value;
-            windows.Meh /= value;
-            windows.Miss /= value;
-
-            return windows;
-        }
     }
 }

osu.Game/Rulesets/Objects/Legacy/Mania/ConvertHit.cs

@@ -14,6 +14,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Mania
 
         public bool NewCombo { get; set; }
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Mania/ConvertHold.cs

@@ -13,6 +13,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Mania
 
         public double Duration => EndTime - StartTime;
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Mania/ConvertSlider.cs

@@ -14,6 +14,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Mania
 
         public bool NewCombo { get; set; }
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Mania/ConvertSpinner.cs

@@ -16,6 +16,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Mania
 
         public float X { get; set; }
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Osu/ConvertHit.cs

@@ -19,6 +19,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Osu
 
         public bool NewCombo { get; set; }
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Osu/ConvertSlider.cs

@@ -19,6 +19,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Osu
 
         public bool NewCombo { get; set; }
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Osu/ConvertSpinner.cs

@@ -21,6 +21,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Osu
 
         public float Y => Position.Y;
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Taiko/ConvertHit.cs

@@ -12,6 +12,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Taiko
     {
         public bool NewCombo { get; set; }
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Taiko/ConvertSlider.cs

@@ -12,6 +12,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Taiko
     {
         public bool NewCombo { get; set; }
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/Objects/Legacy/Taiko/ConvertSpinner.cs

@@ -14,6 +14,6 @@ namespace osu.Game.Rulesets.Objects.Legacy.Taiko
 
         public double Duration => EndTime - StartTime;
 
-        protected override HitWindows CreateHitWindows() => new ConvertHitWindows();
+        protected override HitWindows CreateHitWindows() => null;
     }
 }

osu.Game/Rulesets/UI/Scrolling/ScrollingRulesetContainer.cs

@@ -8,7 +8,6 @@ using osu.Framework.Extensions.IEnumerableExtensions;
 using osu.Framework.Lists;
 using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.ControlPoints;
-using osu.Game.IO.Serialization;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.Timing;
@@ -104,7 +103,7 @@ namespace osu.Game.Rulesets.UI.Scrolling
             if (index < 0)
                 return new MultiplierControlPoint(time);
 
-            return new MultiplierControlPoint(time, DefaultControlPoints[index].DeepClone());
+            return new MultiplierControlPoint(time, DefaultControlPoints[index]);
         }
     }
 }

osu.Game/Screens/Edit/Editor.cs

@@ -26,7 +26,7 @@ namespace osu.Game.Screens.Edit
     {
         protected override BackgroundScreen CreateBackground() => new BackgroundScreenCustom(@"Backgrounds/bg4");
 
-        public override bool ShowOverlaysOnEnter => false;
+        protected override bool HideOverlaysOnEnter => true;
         public override bool AllowBeatmapRulesetChange => false;
 
         private Box bottomBackground;

osu.Game/Screens/Loader.cs

@@ -17,7 +17,9 @@ namespace osu.Game.Screens
     {
         private bool showDisclaimer;
 
-        public override bool ShowOverlaysOnEnter => false;
+        protected override bool HideOverlaysOnEnter => true;
+
+        protected override bool AllowBackButton => false;
 
         public Loader()
         {

osu.Game/Screens/Menu/ButtonSystem.cs

@@ -6,26 +6,29 @@ using System.Collections.Generic;
 using System.Linq;
 using osu.Framework;
 using osu.Framework.Allocation;
+using osu.Framework.Audio;
+using osu.Framework.Audio.Sample;
+using osu.Framework.Configuration;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Input;
+using osu.Framework.Input.Bindings;
+using osu.Framework.Threading;
 using osu.Game.Graphics;
+using osu.Game.Input.Bindings;
 using OpenTK;
 using OpenTK.Graphics;
 using OpenTK.Input;
-using osu.Framework.Audio.Sample;
-using osu.Framework.Audio;
-using osu.Framework.Configuration;
-using osu.Framework.Threading;
 
 namespace osu.Game.Screens.Menu
 {
-    public class ButtonSystem : Container, IStateful<MenuState>
+    public class ButtonSystem : Container, IStateful<MenuState>, IKeyBindingHandler<GlobalAction>
     {
         public event Action<MenuState> StateChanged;
 
-        private readonly BindableBool showOverlays = new BindableBool();
+        private readonly BindableBool hideOverlaysOnEnter = new BindableBool();
+        private readonly BindableBool allowOpeningOverlays = new BindableBool();
 
         public Action OnEdit;
         public Action OnExit;
@@ -133,7 +136,12 @@ namespace osu.Game.Screens.Menu
         [BackgroundDependencyLoader(true)]
         private void load(AudioManager audio, OsuGame game)
         {
-            if (game != null) showOverlays.BindTo(game.ShowOverlays);
+            if (game != null)
+            {
+                hideOverlaysOnEnter.BindTo(game.HideOverlaysOnEnter);
+                allowOpeningOverlays.BindTo(game.AllowOpeningOverlays);
+            }
+
             sampleBack = audio.Sample.Get(@"Menu/button-back-select");
         }
 
@@ -146,7 +154,16 @@ namespace osu.Game.Screens.Menu
                 case Key.Space:
                     logo?.TriggerOnClick(state);
                     return true;
-                case Key.Escape:
+            }
+
+            return false;
+        }
+
+        public bool OnPressed(GlobalAction action)
+        {
+            switch (action)
+            {
+                case GlobalAction.Back:
                     switch (State)
                     {
                         case MenuState.TopLevel:
@@ -155,12 +172,23 @@ namespace osu.Game.Screens.Menu
                         case MenuState.Play:
                             backButton.TriggerOnClick();
                             return true;
+                        default:
+                            return false;
                     }
-
+                default:
                     return false;
             }
+        }
 
-            return false;
+        public bool OnReleased(GlobalAction action)
+        {
+            switch (action)
+            {
+                case GlobalAction.Back:
+                    return true;
+                default:
+                    return false;
+            }
         }
 
         private void onPlay()
@@ -300,8 +328,6 @@ namespace osu.Game.Screens.Menu
 
                     logoDelayedAction = Scheduler.AddDelayed(() =>
                     {
-                        showOverlays.Value = false;
-
                         logo.ClearTransforms(targetMember: nameof(Position));
                         logo.RelativePositionAxes = Axes.Both;
 
@@ -329,7 +355,8 @@ namespace osu.Game.Screens.Menu
                                 logoTracking = true;
 
                                 logo.Impact();
-                                showOverlays.Value = true;
+                                hideOverlaysOnEnter.Value = false;
+                                allowOpeningOverlays.Value = true;
                             }, 200);
                             break;
                         default:
@@ -337,6 +364,7 @@ namespace osu.Game.Screens.Menu
                             logo.ScaleTo(0.5f, 200, Easing.OutQuint);
                             break;
                     }
+
                     break;
                 case MenuState.EnteringMode:
                     logoTracking = true;

osu.Game/Screens/Menu/Disclaimer.cs

@@ -18,7 +18,8 @@ namespace osu.Game.Screens.Menu
         private readonly SpriteIcon icon;
         private Color4 iconColour;
 
-        public override bool ShowOverlaysOnEnter => false;
+        protected override bool HideOverlaysOnEnter => true;
+
         public override bool CursorVisible => false;
 
         public Disclaimer()

osu.Game/Screens/Menu/Intro.cs

@@ -31,7 +31,9 @@ namespace osu.Game.Screens.Menu
         private SampleChannel welcome;
         private SampleChannel seeya;
 
-        public override bool ShowOverlaysOnEnter => false;
+        protected override bool HideOverlaysOnEnter => true;
+        protected override bool AllowOpeningOverlays => false;
+
         public override bool CursorVisible => false;
 
         protected override BackgroundScreen CreateBackground() => new BackgroundScreenEmpty();

osu.Game/Screens/Menu/MainMenu.cs

@@ -14,7 +14,7 @@ using osu.Game.Screens.Backgrounds;
 using osu.Game.Screens.Charts;
 using osu.Game.Screens.Direct;
 using osu.Game.Screens.Edit;
-using osu.Game.Screens.Multi.Screens;
+using osu.Game.Screens.Multi;
 using osu.Game.Screens.Select;
 using osu.Game.Screens.Tournament;
 
@@ -24,7 +24,10 @@ namespace osu.Game.Screens.Menu
     {
         private readonly ButtonSystem buttons;
 
-        public override bool ShowOverlaysOnEnter => buttons.State != MenuState.Initial;
+        protected override bool HideOverlaysOnEnter => buttons.State == MenuState.Initial;
+        protected override bool AllowOpeningOverlays => buttons.State != MenuState.Initial;
+
+        protected override bool AllowBackButton => buttons.State != MenuState.Initial;
 
         private readonly BackgroundScreenDefault background;
         private Screen songSelect;
@@ -54,7 +57,7 @@ namespace osu.Game.Screens.Menu
                             OnDirect = delegate { Push(new OnlineListing()); },
                             OnEdit = delegate { Push(new Editor()); },
                             OnSolo = delegate { Push(consumeSongSelect()); },
-                            OnMulti = delegate { Push(new Lobby()); },
+                            OnMulti = delegate { Push(new Multiplayer()); },
                             OnExit = Exit,
                         }
                     }

osu.Game/Screens/Multi/Components/DrawableRoom.cs

@@ -1,6 +1,8 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
+using osu.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Configuration;
 using osu.Framework.Extensions.Color4Extensions;
@@ -13,6 +15,7 @@ using osu.Game.Beatmaps.Drawables;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Graphics.UserInterface;
 using osu.Game.Online.Multiplayer;
 using osu.Game.Users;
 using OpenTK;
@@ -20,20 +23,17 @@ using OpenTK.Graphics;
 
 namespace osu.Game.Screens.Multi.Components
 {
-    public class DrawableRoom : OsuClickableContainer
+    public class DrawableRoom : OsuClickableContainer, IStateful<SelectionState>
     {
+        private const float corner_radius = 5;
+        private const float selection_border_width = 4;
         private const float transition_duration = 100;
         private const float content_padding = 10;
         private const float height = 100;
         private const float side_strip_width = 5;
         private const float cover_width = 145;
 
-        private readonly Box sideStrip;
+        private readonly Box selectionBox;
-        private readonly Container coverContainer;
-        private readonly OsuSpriteText name, status, beatmapTitle, beatmapDash, beatmapArtist;
-        private readonly FillFlowContainer<OsuSpriteText> beatmapInfoFlow;
-        private readonly ParticipantInfo participantInfo;
-        private readonly ModeTypeInfo modeTypeInfo;
 
         private readonly Bindable<string> nameBind = new Bindable<string>();
         private readonly Bindable<User> hostBind = new Bindable<User>();
@@ -42,136 +42,228 @@ namespace osu.Game.Screens.Multi.Components
         private readonly Bindable<BeatmapInfo> beatmapBind = new Bindable<BeatmapInfo>();
         private readonly Bindable<User[]> participantsBind = new Bindable<User[]>();
 
-        private OsuColour colours;
-        private LocalisationEngine localisation;
-
         public readonly Room Room;
 
+        private SelectionState state;
+        public SelectionState State
+        {
+            get { return state; }
+            set
+            {
+                if (value == state) return;
+                state = value;
+
+                if (state == SelectionState.Selected)
+                    selectionBox.FadeIn(transition_duration);
+                else
+                    selectionBox.FadeOut(transition_duration);
+
+                StateChanged?.Invoke(State);
+            }
+        }
+
+        public event Action<SelectionState> StateChanged;
+
         public DrawableRoom(Room room)
         {
             Room = room;
 
             RelativeSizeAxes = Axes.X;
-            Height = height;
+            Height = height + selection_border_width * 2;
-            CornerRadius = 5;
+            CornerRadius = corner_radius + selection_border_width / 2;
             Masking = true;
-            EdgeEffect = new EdgeEffectParameters
+
+            // create selectionBox here so State can be set before being loaded
+            selectionBox = new Box
             {
-                Type = EdgeEffectType.Shadow,
+                RelativeSizeAxes = Axes.Both,
-                Colour = Color4.Black.Opacity(40),
+                Alpha = 0f,
-                Radius = 5,
             };
 
+            Action += () => State = SelectionState.Selected;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours, LocalisationEngine localisation)
+        {
+            Box sideStrip;
+            Container coverContainer;
+            OsuSpriteText name, status, beatmapTitle, beatmapDash, beatmapArtist;
+            ParticipantInfo participantInfo;
+            ModeTypeInfo modeTypeInfo;
+
             Children = new Drawable[]
             {
-                new Box
+                selectionBox,
-                {
-                    RelativeSizeAxes = Axes.Both,
-                    Colour = OsuColour.FromHex(@"212121"),
-                },
-                sideStrip = new Box
-                {
-                    RelativeSizeAxes = Axes.Y,
-                    Width = side_strip_width,
-                },
-                new Container
-                {
-                    Width = cover_width,
-                    RelativeSizeAxes = Axes.Y,
-                    Masking = true,
-                    Margin = new MarginPadding { Left = side_strip_width },
-                    Children = new Drawable[]
-                    {
-                        new Box
-                        {
-                            RelativeSizeAxes = Axes.Both,
-                            Colour = Color4.Black,
-                        },
-                        coverContainer = new Container
-                        {
-                            RelativeSizeAxes = Axes.Both,
-                        },
-                    },
-                },
                 new Container
                 {
                     RelativeSizeAxes = Axes.Both,
-                    Padding = new MarginPadding
+                    Padding = new MarginPadding(selection_border_width),
+                    Child = new Container
                     {
-                        Vertical = content_padding,
+                        RelativeSizeAxes = Axes.Both,
-                        Left = side_strip_width + cover_width + content_padding,
+                        Masking = true,
-                        Right = content_padding,
+                        CornerRadius = corner_radius,
-                    },
+                        EdgeEffect = new EdgeEffectParameters
-                    Children = new Drawable[]
-                    {
-                        new FillFlowContainer
                         {
-                            RelativeSizeAxes = Axes.X,
+                            Type = EdgeEffectType.Shadow,
-                            AutoSizeAxes = Axes.Y,
+                            Colour = Color4.Black.Opacity(40),
-                            Direction = FillDirection.Vertical,
+                            Radius = 5,
-                            Spacing = new Vector2(5f),
+                        },
-                            Children = new Drawable[]
+                        Children = new Drawable[]
+                        {
+                            new Box
                             {
-                                name = new OsuSpriteText
+                                RelativeSizeAxes = Axes.Both,
-                                {
+                                Colour = OsuColour.FromHex(@"212121"),
-                                    TextSize = 18,
-                                },
-                                participantInfo = new ParticipantInfo(),
                             },
-                        },
+                            sideStrip = new Box
-                        new FillFlowContainer
-                        {
-                            Anchor = Anchor.BottomLeft,
-                            Origin = Anchor.BottomLeft,
-                            RelativeSizeAxes = Axes.X,
-                            AutoSizeAxes = Axes.Y,
-                            Direction = FillDirection.Vertical,
-                            Children = new Drawable[]
                             {
-                                status = new OsuSpriteText
+                                RelativeSizeAxes = Axes.Y,
+                                Width = side_strip_width,
+                            },
+                            new Container
+                            {
+                                Width = cover_width,
+                                RelativeSizeAxes = Axes.Y,
+                                Masking = true,
+                                Margin = new MarginPadding { Left = side_strip_width },
+                                Children = new Drawable[]
                                 {
-                                    TextSize = 14,
+                                    new Box
-                                    Font = @"Exo2.0-Bold",
-                                },
-                                beatmapInfoFlow = new FillFlowContainer<OsuSpriteText>
-                                {
-                                    RelativeSizeAxes = Axes.X,
-                                    AutoSizeAxes = Axes.Y,
-                                    Direction = FillDirection.Horizontal,
-                                    Children = new[]
                                     {
-                                        beatmapTitle = new OsuSpriteText
+                                        RelativeSizeAxes = Axes.Both,
+                                        Colour = Color4.Black,
+                                    },
+                                    coverContainer = new Container
+                                    {
+                                        RelativeSizeAxes = Axes.Both,
+                                    },
+                                },
+                            },
+                            new Container
+                            {
+                                RelativeSizeAxes = Axes.Both,
+                                Padding = new MarginPadding
+                                {
+                                    Vertical = content_padding,
+                                    Left = side_strip_width + cover_width + content_padding,
+                                    Right = content_padding,
+                                },
+                                Children = new Drawable[]
+                                {
+                                    new FillFlowContainer
+                                    {
+                                        RelativeSizeAxes = Axes.X,
+                                        AutoSizeAxes = Axes.Y,
+                                        Direction = FillDirection.Vertical,
+                                        Spacing = new Vector2(5f),
+                                        Children = new Drawable[]
                                         {
-                                            TextSize = 14,
+                                            name = new OsuSpriteText
-                                            Font = @"Exo2.0-BoldItalic",
+                                            {
+                                                TextSize = 18,
+                                            },
+                                            participantInfo = new ParticipantInfo(),
                                         },
-                                        beatmapDash = new OsuSpriteText
+                                    },
+                                    new FillFlowContainer
+                                    {
+                                        Anchor = Anchor.BottomLeft,
+                                        Origin = Anchor.BottomLeft,
+                                        RelativeSizeAxes = Axes.X,
+                                        AutoSizeAxes = Axes.Y,
+                                        Direction = FillDirection.Vertical,
+                                        Children = new Drawable[]
                                         {
-                                            TextSize = 14,
+                                            status = new OsuSpriteText
-                                            Font = @"Exo2.0-BoldItalic",
+                                            {
-                                        },
+                                                TextSize = 14,
-                                        beatmapArtist = new OsuSpriteText
+                                                Font = @"Exo2.0-Bold",
-                                        {
+                                            },
-                                            TextSize = 14,
+                                            new FillFlowContainer<OsuSpriteText>
-                                            Font = @"Exo2.0-RegularItalic",
+                                            {
+                                                RelativeSizeAxes = Axes.X,
+                                                AutoSizeAxes = Axes.Y,
+                                                Colour = colours.Gray9,
+                                                Direction = FillDirection.Horizontal,
+                                                Children = new[]
+                                                {
+                                                    beatmapTitle = new OsuSpriteText
+                                                    {
+                                                        TextSize = 14,
+                                                        Font = @"Exo2.0-BoldItalic",
+                                                    },
+                                                    beatmapDash = new OsuSpriteText
+                                                    {
+                                                        TextSize = 14,
+                                                        Font = @"Exo2.0-BoldItalic",
+                                                    },
+                                                    beatmapArtist = new OsuSpriteText
+                                                    {
+                                                        TextSize = 14,
+                                                        Font = @"Exo2.0-RegularItalic",
+                                                    },
+                                                },
+                                            },
                                         },
                                     },
+                                    modeTypeInfo = new ModeTypeInfo
+                                    {
+                                        Anchor = Anchor.BottomRight,
+                                        Origin = Anchor.BottomRight,
+                                    },
                                 },
                             },
                         },
-                        modeTypeInfo = new ModeTypeInfo
-                        {
-                            Anchor = Anchor.BottomRight,
-                            Origin = Anchor.BottomRight,
-                        },
                     },
                 },
             };
 
-            nameBind.ValueChanged += displayName;
+            nameBind.ValueChanged += n => name.Text = n;
-            hostBind.ValueChanged += displayUser;
+            hostBind.ValueChanged += h => participantInfo.Host = h;
-            typeBind.ValueChanged += displayGameType;
+            typeBind.ValueChanged += m => modeTypeInfo.Type = m;
-            participantsBind.ValueChanged += displayParticipants;
+            participantsBind.ValueChanged += p => participantInfo.Participants = p;
+
+            statusBind.ValueChanged += s =>
+            {
+                status.Text = s.Message;
+
+                foreach (Drawable d in new Drawable[] { selectionBox, sideStrip, status })
+                    d.FadeColour(s.GetAppropriateColour(colours), 100);
+            };
+
+            beatmapBind.ValueChanged += b =>
+            {
+                modeTypeInfo.Beatmap = b;
+
+                if (b != null)
+                {
+                    coverContainer.FadeIn(transition_duration);
+
+                    LoadComponentAsync(new BeatmapSetCover(b.BeatmapSet)
+                    {
+                        Anchor = Anchor.Centre,
+                        Origin = Anchor.Centre,
+                        FillMode = FillMode.Fill,
+                        OnLoadComplete = d => d.FadeInFromZero(400, Easing.Out),
+                    }, coverContainer.Add);
+
+                    beatmapTitle.Current = localisation.GetUnicodePreference(b.Metadata.TitleUnicode, b.Metadata.Title);
+                    beatmapDash.Text = @" - ";
+                    beatmapArtist.Current = localisation.GetUnicodePreference(b.Metadata.ArtistUnicode, b.Metadata.Artist);
+                }
+                else
+                {
+                    coverContainer.FadeOut(transition_duration);
+
+                    beatmapTitle.Current = null;
+                    beatmapArtist.Current = null;
+
+                    beatmapTitle.Text = "Changing map";
+                    beatmapDash.Text = beatmapArtist.Text = string.Empty;
+                }
+            };
 
             nameBind.BindTo(Room.Name);
             hostBind.BindTo(Room.Host);
@@ -180,83 +272,5 @@ namespace osu.Game.Screens.Multi.Components
             beatmapBind.BindTo(Room.Beatmap);
             participantsBind.BindTo(Room.Participants);
         }
-
-        [BackgroundDependencyLoader]
-        private void load(OsuColour colours, LocalisationEngine localisation)
-        {
-            this.localisation = localisation;
-            this.colours = colours;
-
-            beatmapInfoFlow.Colour = colours.Gray9;
-
-            //binded here instead of ctor because dependencies are needed
-            statusBind.ValueChanged += displayStatus;
-            beatmapBind.ValueChanged += displayBeatmap;
-
-            statusBind.TriggerChange();
-            beatmapBind.TriggerChange();
-        }
-
-        private void displayName(string value)
-        {
-            name.Text = value;
-        }
-
-        private void displayUser(User value)
-        {
-            participantInfo.Host = value;
-        }
-
-        private void displayStatus(RoomStatus value)
-        {
-            if (value == null) return;
-            status.Text = value.Message;
-
-            foreach (Drawable d in new Drawable[] { sideStrip, status })
-                d.FadeColour(value.GetAppropriateColour(colours), 100);
-        }
-
-        private void displayGameType(GameType value)
-        {
-            modeTypeInfo.Type = value;
-        }
-
-        private void displayBeatmap(BeatmapInfo value)
-        {
-            modeTypeInfo.Beatmap = value;
-
-            if (value != null)
-            {
-                coverContainer.FadeIn(transition_duration);
-
-                LoadComponentAsync(new BeatmapSetCover(value.BeatmapSet)
-                {
-                    Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre,
-                    FillMode = FillMode.Fill,
-                    OnLoadComplete = d => d.FadeInFromZero(400, Easing.Out),
-                },
-                coverContainer.Add);
-
-                beatmapTitle.Current = localisation.GetUnicodePreference(value.Metadata.TitleUnicode, value.Metadata.Title);
-                beatmapDash.Text = @" - ";
-                beatmapArtist.Current = localisation.GetUnicodePreference(value.Metadata.ArtistUnicode, value.Metadata.Artist);
-            }
-            else
-            {
-                coverContainer.FadeOut(transition_duration);
-
-                beatmapTitle.Current = null;
-                beatmapArtist.Current = null;
-
-                beatmapTitle.Text = "Changing map";
-                beatmapDash.Text = beatmapArtist.Text = string.Empty;
-            }
-        }
-
-        private void displayParticipants(User[] value)
-        {
-            participantInfo.Participants = value;
-        }
     }
 }

osu.Game/Screens/Multi/Components/RoomInspector.cs

@@ -25,17 +25,9 @@ namespace osu.Game.Screens.Multi.Components
 {
     public class RoomInspector : Container
     {
-        private readonly MarginPadding contentPadding = new MarginPadding { Horizontal = 20, Vertical = 10 };
         private const float transition_duration = 100;
 
-        private readonly Box statusStrip;
+        private readonly MarginPadding contentPadding = new MarginPadding { Horizontal = 20, Vertical = 10 };
-        private readonly Container coverContainer;
-        private readonly FillFlowContainer topFlow, participantsFlow;
-        private readonly ModeTypeInfo modeTypeInfo;
-        private readonly OsuSpriteText participants, participantsSlash, maxParticipants, name, status, beatmapTitle, beatmapDash, beatmapArtist, beatmapAuthor;
-        private readonly ParticipantInfo participantInfo;
-        private readonly ScrollContainer participantsScroll;
-
         private readonly Bindable<string> nameBind = new Bindable<string>();
         private readonly Bindable<User> hostBind = new Bindable<User>();
         private readonly Bindable<RoomStatus> statusBind = new Bindable<RoomStatus>();
@@ -45,10 +37,14 @@ namespace osu.Game.Screens.Multi.Components
         private readonly Bindable<User[]> participantsBind = new Bindable<User[]>();
 
         private OsuColour colours;
-        private LocalisationEngine localisation;
+        private Box statusStrip;
+        private Container coverContainer;
+        private FillFlowContainer topFlow, participantsFlow, participantNumbersFlow, infoPanelFlow;
+        private OsuSpriteText name, status;
+        private ScrollContainer participantsScroll;
+        private ParticipantInfo participantInfo;
 
         private Room room;
-
         public Room Room
         {
             get { return room; }
@@ -57,20 +53,36 @@ namespace osu.Game.Screens.Multi.Components
                 if (value == room) return;
                 room = value;
 
-                nameBind.BindTo(Room.Name);
+                nameBind.UnbindBindings();
-                hostBind.BindTo(Room.Host);
+                hostBind.UnbindBindings();
-                statusBind.BindTo(Room.Status);
+                statusBind.UnbindBindings();
-                typeBind.BindTo(Room.Type);
+                typeBind.UnbindBindings();
-                beatmapBind.BindTo(Room.Beatmap);
+                beatmapBind.UnbindBindings();
-                maxParticipantsBind.BindTo(Room.MaxParticipants);
+                maxParticipantsBind.UnbindBindings();
-                participantsBind.BindTo(Room.Participants);
+                participantsBind.UnbindBindings();
+
+                if (room != null)
+                {
+                    nameBind.BindTo(room.Name);
+                    hostBind.BindTo(room.Host);
+                    statusBind.BindTo(room.Status);
+                    typeBind.BindTo(room.Type);
+                    beatmapBind.BindTo(room.Beatmap);
+                    maxParticipantsBind.BindTo(room.MaxParticipants);
+                    participantsBind.BindTo(room.Participants);
+                }
+
+                updateState();
             }
         }
 
-        public RoomInspector()
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours, LocalisationEngine localisation)
         {
-            Width = 520;
+            this.colours = colours;
-            RelativeSizeAxes = Axes.Y;
+
+            ModeTypeInfo modeTypeInfo;
+            OsuSpriteText participants, participantsSlash, maxParticipants, beatmapTitle, beatmapDash, beatmapArtist, beatmapAuthor;
 
             Children = new Drawable[]
             {
@@ -120,7 +132,7 @@ namespace osu.Game.Screens.Multi.Components
                                     Padding = new MarginPadding(20),
                                     Children = new Drawable[]
                                     {
-                                        new FillFlowContainer
+                                        participantNumbersFlow = new FillFlowContainer
                                         {
                                             Anchor = Anchor.TopRight,
                                             Origin = Anchor.TopRight,
@@ -178,6 +190,7 @@ namespace osu.Game.Screens.Multi.Components
                                     RelativeSizeAxes = Axes.X,
                                     AutoSizeAxes = Axes.Y,
                                     Direction = FillDirection.Vertical,
+                                    LayoutDuration = transition_duration,
                                     Padding = contentPadding,
                                     Spacing = new Vector2(0f, 5f),
                                     Children = new Drawable[]
@@ -187,7 +200,7 @@ namespace osu.Game.Screens.Multi.Components
                                             TextSize = 14,
                                             Font = @"Exo2.0-Bold",
                                         },
-                                        new FillFlowContainer
+                                        infoPanelFlow = new FillFlowContainer
                                         {
                                             AutoSizeAxes = Axes.X,
                                             Height = 30,
@@ -229,6 +242,7 @@ namespace osu.Game.Screens.Multi.Components
                                                             Anchor = Anchor.BottomLeft,
                                                             Origin = Anchor.BottomLeft,
                                                             TextSize = 14,
+                                                            Colour = colours.Gray9,
                                                         },
                                                     },
                                                 },
@@ -269,27 +283,68 @@ namespace osu.Game.Screens.Multi.Components
                 },
             };
 
-            nameBind.ValueChanged += displayName;
+            nameBind.ValueChanged += n => name.Text = n;
-            hostBind.ValueChanged += displayUser;
+            hostBind.ValueChanged += h => participantInfo.Host = h;
-            typeBind.ValueChanged += displayGameType;
+            typeBind.ValueChanged += t => modeTypeInfo.Type = t;
-            maxParticipantsBind.ValueChanged += displayMaxParticipants;
-            participantsBind.ValueChanged += displayParticipants;
-        }
-
-        [BackgroundDependencyLoader]
-        private void load(OsuColour colours, LocalisationEngine localisation)
-        {
-            this.localisation = localisation;
-            this.colours = colours;
-
-            beatmapAuthor.Colour = colours.Gray9;
-
-            //binded here instead of ctor because dependencies are needed
             statusBind.ValueChanged += displayStatus;
-            beatmapBind.ValueChanged += displayBeatmap;
 
-            statusBind.TriggerChange();
+            beatmapBind.ValueChanged += b =>
-            beatmapBind.TriggerChange();
+            {
+                modeTypeInfo.Beatmap = b;
+
+                if (b != null)
+                {
+                    coverContainer.FadeIn(transition_duration);
+
+                    LoadComponentAsync(new BeatmapSetCover(b.BeatmapSet)
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Anchor = Anchor.Centre,
+                        Origin = Anchor.Centre,
+                        FillMode = FillMode.Fill,
+                        OnLoadComplete = d => d.FadeInFromZero(400, Easing.Out),
+                    }, coverContainer.Add);
+
+                    beatmapTitle.Current = localisation.GetUnicodePreference(b.Metadata.TitleUnicode, b.Metadata.Title);
+                    beatmapDash.Text = @" - ";
+                    beatmapArtist.Current = localisation.GetUnicodePreference(b.Metadata.ArtistUnicode, b.Metadata.Artist);
+                    beatmapAuthor.Text = $"mapped by {b.Metadata.Author}";
+                }
+                else
+                {
+                    coverContainer.FadeOut(transition_duration);
+
+                    beatmapTitle.Current = null;
+                    beatmapArtist.Current = null;
+
+                    beatmapTitle.Text = "Changing map";
+                    beatmapDash.Text = beatmapArtist.Text = beatmapAuthor.Text = string.Empty;
+                }
+            };
+
+            maxParticipantsBind.ValueChanged += m =>
+            {
+                if (m == null)
+                {
+                    participantsSlash.FadeOut(transition_duration);
+                    maxParticipants.FadeOut(transition_duration);
+                }
+                else
+                {
+                    participantsSlash.FadeIn(transition_duration);
+                    maxParticipants.FadeIn(transition_duration);
+                    maxParticipants.Text = m.ToString();
+                }
+            };
+
+            participantsBind.ValueChanged += p =>
+            {
+                participants.Text = p.Length.ToString();
+                participantInfo.Participants = p;
+                participantsFlow.ChildrenEnumerable = p.Select(u => new UserTile(u));
+            };
+
+            updateState();
         }
 
         protected override void UpdateAfterChildren()
@@ -299,84 +354,39 @@ namespace osu.Game.Screens.Multi.Components
             participantsScroll.Height = DrawHeight - topFlow.DrawHeight;
         }
 
-        private void displayName(string value)
+        private void displayStatus(RoomStatus s)
         {
-            name.Text = value;
+            status.Text = s.Message;
+
+            Color4 c = s.GetAppropriateColour(colours);
+            statusStrip.FadeColour(c, transition_duration);
+            status.FadeColour(c, transition_duration);
         }
 
-        private void displayUser(User value)
+        private void updateState()
         {
-            participantInfo.Host = value;
+            if (Room == null)
-        }
-
-        private void displayStatus(RoomStatus value)
-        {
-            status.Text = value.Message;
-
-            foreach (Drawable d in new Drawable[] { statusStrip, status })
-                d.FadeColour(value.GetAppropriateColour(colours), transition_duration);
-        }
-
-        private void displayGameType(GameType value)
-        {
-            modeTypeInfo.Type = value;
-        }
-
-        private void displayBeatmap(BeatmapInfo value)
-        {
-            modeTypeInfo.Beatmap = value;
-
-            if (value != null)
-            {
-                coverContainer.FadeIn(transition_duration);
-
-                LoadComponentAsync(new BeatmapSetCover(value.BeatmapSet)
-                {
-                    RelativeSizeAxes = Axes.Both,
-                    Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre,
-                    FillMode = FillMode.Fill,
-                    OnLoadComplete = d => d.FadeInFromZero(400, Easing.Out),
-                },
-                coverContainer.Add);
-
-                beatmapTitle.Current = localisation.GetUnicodePreference(value.Metadata.TitleUnicode, value.Metadata.Title);
-                beatmapDash.Text = @" - ";
-                beatmapArtist.Current = localisation.GetUnicodePreference(value.Metadata.ArtistUnicode, value.Metadata.Artist);
-                beatmapAuthor.Text = $"mapped by {value.Metadata.Author}";
-            }
-            else
             {
                 coverContainer.FadeOut(transition_duration);
+                participantsFlow.FadeOut(transition_duration);
+                participantNumbersFlow.FadeOut(transition_duration);
+                infoPanelFlow.FadeOut(transition_duration);
+                name.FadeOut(transition_duration);
+                participantInfo.FadeOut(transition_duration);
 
-                beatmapTitle.Current = null;
+                displayStatus(new RoomStatusNoneSelected());
-                beatmapArtist.Current = null;
-
-                beatmapTitle.Text = "Changing map";
-                beatmapDash.Text = beatmapArtist.Text = beatmapAuthor.Text = string.Empty;
-            }
-        }
-
-        private void displayMaxParticipants(int? value)
-        {
-            if (value == null)
-            {
-                participantsSlash.FadeOut(transition_duration);
-                maxParticipants.FadeOut(transition_duration);
             }
             else
             {
-                participantsSlash.FadeIn(transition_duration);
+                participantsFlow.FadeIn(transition_duration);
-                maxParticipants.FadeIn(transition_duration);
+                participantNumbersFlow.FadeIn(transition_duration);
-                maxParticipants.Text = value.ToString();
+                infoPanelFlow.FadeIn(transition_duration);
-            }
+                name.FadeIn(transition_duration);
-        }
+                participantInfo.FadeIn(transition_duration);
 
-        private void displayParticipants(User[] value)
+                statusBind.TriggerChange();
-        {
+                beatmapBind.TriggerChange();
-            participants.Text = value.Length.ToString();
+            }
-            participantInfo.Participants = value;
-            participantsFlow.ChildrenEnumerable = value.Select(u => new UserTile(u));
         }
 
         private class UserTile : Container, IHasTooltip
@@ -407,5 +417,11 @@ namespace osu.Game.Screens.Multi.Components
                 };
             }
         }
+
+        private class RoomStatusNoneSelected : RoomStatus
+        {
+            public override string Message => @"No Room Selected";
+            public override Color4 GetAppropriateColour(OsuColour colours) => colours.Gray8;
+        }
     }
 }

osu.Game/Screens/Multi/Header.cs

@@ -0,0 +1,112 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Screens;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Overlays.SearchableList;
+using OpenTK;
+using OpenTK.Graphics;
+
+namespace osu.Game.Screens.Multi
+{
+    public class Header : Container
+    {
+        public const float HEIGHT = 121;
+
+        private readonly OsuSpriteText screenTitle;
+        private readonly HeaderBreadcrumbControl breadcrumbs;
+
+        public Header(Screen initialScreen)
+        {
+            RelativeSizeAxes = Axes.X;
+            Height = HEIGHT;
+
+            Children = new Drawable[]
+            {
+                new Box
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Colour = OsuColour.FromHex(@"2f2043"),
+                },
+                new Container
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Padding = new MarginPadding { Horizontal = SearchableListOverlay.WIDTH_PADDING },
+                    Children = new Drawable[]
+                    {
+                        new FillFlowContainer
+                        {
+                            Anchor = Anchor.CentreLeft,
+                            Origin = Anchor.BottomLeft,
+                            Position = new Vector2(-35f, 5f),
+                            AutoSizeAxes = Axes.Both,
+                            Direction = FillDirection.Horizontal,
+                            Spacing = new Vector2(10f, 0f),
+                            Children = new Drawable[]
+                            {
+                                new SpriteIcon
+                                {
+                                    Size = new Vector2(25),
+                                    Icon = FontAwesome.fa_osu_multi,
+                                },
+                                new FillFlowContainer
+                                {
+                                    AutoSizeAxes = Axes.Both,
+                                    Direction = FillDirection.Horizontal,
+                                    Children = new[]
+                                    {
+                                        new OsuSpriteText
+                                        {
+                                            Text = "multiplayer ",
+                                            TextSize = 25,
+                                        },
+                                        screenTitle = new OsuSpriteText
+                                        {
+                                            TextSize = 25,
+                                            Font = @"Exo2.0-Light",
+                                        },
+                                    },
+                                },
+                            },
+                        },
+                        breadcrumbs = new HeaderBreadcrumbControl(initialScreen)
+                        {
+                            Anchor = Anchor.BottomLeft,
+                            Origin = Anchor.BottomLeft,
+                            RelativeSizeAxes = Axes.X,
+                        },
+                    },
+                },
+            };
+
+            breadcrumbs.Current.ValueChanged += s => screenTitle.Text = s.ToString();
+            breadcrumbs.Current.TriggerChange();
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            screenTitle.Colour = colours.Yellow;
+            breadcrumbs.StripColour = colours.Green;
+        }
+
+        private class HeaderBreadcrumbControl : ScreenBreadcrumbControl
+        {
+            public HeaderBreadcrumbControl(Screen initialScreen) : base(initialScreen)
+            {
+            }
+
+            protected override void LoadComplete()
+            {
+                base.LoadComplete();
+                AccentColour = Color4.White;
+            }
+        }
+    }
+}

osu.Game/Screens/Multi/Multiplayer.cs

@@ -0,0 +1,100 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Screens;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Backgrounds;
+using osu.Game.Graphics.Containers;
+using osu.Game.Screens.Multi.Screens;
+
+namespace osu.Game.Screens.Multi
+{
+    public class Multiplayer : OsuScreen
+    {
+        private readonly MultiplayerWaveContainer waves;
+
+        protected override Container<Drawable> Content => waves;
+
+        public Multiplayer()
+        {
+            InternalChild = waves = new MultiplayerWaveContainer
+            {
+                RelativeSizeAxes = Axes.Both,
+            };
+
+            Lobby lobby;
+            Children = new Drawable[]
+            {
+                new Container
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Masking = true,
+                    Children = new Drawable[]
+                    {
+                        new Box
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Colour = OsuColour.FromHex(@"3e3a44"),
+                        },
+                        new Triangles
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            ColourLight = OsuColour.FromHex(@"3c3842"),
+                            ColourDark = OsuColour.FromHex(@"393540"),
+                            TriangleScale = 5,
+                        },
+                    },
+                },
+                new Container
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Padding = new MarginPadding { Top = Header.HEIGHT },
+                    Child = lobby = new Lobby(),
+                },
+                new Header(lobby),
+            };
+
+            lobby.Exited += s => Exit();
+        }
+
+        protected override void OnEntering(Screen last)
+        {
+            base.OnEntering(last);
+            waves.Show();
+        }
+
+        protected override bool OnExiting(Screen next)
+        {
+            waves.Hide();
+            return base.OnExiting(next);
+        }
+
+        protected override void OnResuming(Screen last)
+        {
+            base.OnResuming(last);
+            waves.Show();
+        }
+
+        protected override void OnSuspending(Screen next)
+        {
+            base.OnSuspending(next);
+            waves.Hide();
+        }
+
+        private class MultiplayerWaveContainer : WaveContainer
+        {
+            protected override bool StartHidden => true;
+
+            public MultiplayerWaveContainer()
+            {
+                FirstWaveColour = OsuColour.FromHex(@"654d8c");
+                SecondWaveColour = OsuColour.FromHex(@"554075");
+                ThirdWaveColour = OsuColour.FromHex(@"44325e");
+                FourthWaveColour = OsuColour.FromHex(@"392850");
+            }
+        }
+    }
+}

osu.Game/Screens/OsuScreen.cs

@@ -3,37 +3,48 @@
 
 using System;
 using osu.Framework.Allocation;
+using osu.Framework.Audio;
+using osu.Framework.Audio.Sample;
 using osu.Framework.Configuration;
+using osu.Framework.Graphics;
+using osu.Framework.Input;
+using osu.Framework.Input.Bindings;
 using osu.Framework.Screens;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics.Containers;
-using OpenTK;
+using osu.Game.Input.Bindings;
-using osu.Framework.Audio.Sample;
-using osu.Framework.Audio;
-using osu.Framework.Graphics;
 using osu.Game.Rulesets;
 using osu.Game.Screens.Menu;
-using osu.Framework.Input;
+using OpenTK;
 using OpenTK.Input;
 
 namespace osu.Game.Screens
 {
-    public abstract class OsuScreen : Screen
+    public abstract class OsuScreen : Screen, IKeyBindingHandler<GlobalAction>
     {
         public BackgroundScreen Background { get; private set; }
 
+        protected virtual bool AllowBackButton => true;
+
         /// <summary>
         /// Override to create a BackgroundMode for the current screen.
         /// Note that the instance created may not be the used instance if it matches the BackgroundMode equality clause.
         /// </summary>
         protected virtual BackgroundScreen CreateBackground() => null;
 
-        protected BindableBool ShowOverlays = new BindableBool();
+        private readonly BindableBool hideOverlaysOnEnter = new BindableBool();
 
         /// <summary>
-        /// Whether overlays should be shown when this screen is entered or resumed.
+        /// Whether overlays should be hidden when this screen is entered or resumed.
         /// </summary>
-        public virtual bool ShowOverlaysOnEnter => true;
+        protected virtual bool HideOverlaysOnEnter => hideOverlaysOnEnter;
+
+        private readonly BindableBool allowOpeningOverlays = new BindableBool();
+
+        /// <summary>
+        /// Whether overlays should be able to be opened while this screen is active.
+        /// </summary>
+        protected virtual bool AllowOpeningOverlays => allowOpeningOverlays;
 
         /// <summary>
         /// Whether this <see cref="OsuScreen"/> allows the cursor to be displayed.
@@ -84,12 +95,26 @@ namespace osu.Game.Screens
             if (osuGame != null)
             {
                 Ruleset.BindTo(osuGame.Ruleset);
-                ShowOverlays.BindTo(osuGame.ShowOverlays);
+                hideOverlaysOnEnter.BindTo(osuGame.HideOverlaysOnEnter);
+                allowOpeningOverlays.BindTo(osuGame.AllowOpeningOverlays);
             }
 
             sampleExit = audio.Sample.Get(@"UI/screen-back");
         }
 
+        public bool OnPressed(GlobalAction action)
+        {
+            if (action == GlobalAction.Back && AllowBackButton)
+            {
+                Exit();
+                return true;
+            }
+
+            return false;
+        }
+
+        public bool OnReleased(GlobalAction action) => action == GlobalAction.Back && AllowBackButton;
+
         protected override bool OnKeyDown(InputState state, KeyDownEventArgs args)
         {
             if (args.Repeat || !IsCurrentScreen) return false;
@@ -203,7 +228,8 @@ namespace osu.Game.Screens
             if (backgroundParallaxContainer != null)
                 backgroundParallaxContainer.ParallaxAmount = ParallaxContainer.DEFAULT_PARALLAX_AMOUNT * BackgroundParallaxAmount;
 
-            ShowOverlays.Value = ShowOverlaysOnEnter;
+            hideOverlaysOnEnter.Value = HideOverlaysOnEnter;
+            allowOpeningOverlays.Value = AllowOpeningOverlays;
         }
 
         private void onExitingLogo()

osu.Game/Screens/Play/Player.cs

@@ -35,7 +35,7 @@ namespace osu.Game.Screens.Play
     {
         protected override float BackgroundParallaxAmount => 0.1f;
 
-        public override bool ShowOverlaysOnEnter => false;
+        protected override bool HideOverlaysOnEnter => true;
 
         public Action RestartRequested;
 
@@ -45,6 +45,8 @@ namespace osu.Game.Screens.Play
         public bool AllowLeadIn { get; set; } = true;
         public bool AllowResults { get; set; } = true;
 
+        protected override bool AllowBackButton => false;
+
         private Bindable<bool> mouseWheelDisabled;
         private Bindable<double> userAudioOffset;
 

osu.Game/Screens/Play/PlayerLoader.cs

@@ -25,8 +25,8 @@ namespace osu.Game.Screens.Play
 
         private BeatmapMetadataDisplay info;
 
-        private bool showOverlays = true;
+        private bool hideOverlays;
-        public override bool ShowOverlaysOnEnter => showOverlays;
+        protected override bool HideOverlaysOnEnter => hideOverlays;
 
         private Task loadTask;
 
@@ -36,7 +36,7 @@ namespace osu.Game.Screens.Play
 
             player.RestartRequested = () =>
             {
-                showOverlays = false;
+                hideOverlays = true;
                 ValidForResume = true;
             };
         }

osu.Game/Screens/Select/FilterControl.cs

@@ -190,7 +190,5 @@ namespace osu.Game.Screens.Select
         protected override bool OnMouseMove(InputState state) => true;
 
         protected override bool OnClick(InputState state) => true;
-
-        protected override bool OnDragStart(InputState state) => true;
     }
 }

osu.Game/Screens/Select/Footer.cs

@@ -141,7 +141,5 @@ namespace osu.Game.Screens.Select
         protected override bool OnMouseDown(InputState state, MouseDownEventArgs args) => true;
 
         protected override bool OnClick(InputState state) => true;
-
-        protected override bool OnDragStart(InputState state) => true;
     }
 }

osu.Game/Screens/Select/MatchSongSelect.cs

@@ -7,7 +7,12 @@ namespace osu.Game.Screens.Select
     {
         protected override bool OnSelectionFinalised()
         {
-            Exit();
+            Schedule(() =>
+            {
+                // needs to be scheduled else we enter an infinite feedback loop.
+                if (IsCurrentScreen) Exit();
+            });
+
             return true;
         }
     }

osu.Game/Screens/Tournament/Drawings.cs

@@ -29,7 +29,7 @@ namespace osu.Game.Screens.Tournament
     {
         private const string results_filename = "drawings_results.txt";
 
-        public override bool ShowOverlaysOnEnter => false;
+        protected override bool HideOverlaysOnEnter => true;
 
         protected override BackgroundScreen CreateBackground() => new BackgroundScreenDefault();