Add base DrawableHitObject + HitObjectStartTimeComparer.

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

@@ -15,28 +15,51 @@ using System.Linq;
 
 namespace osu.Game.Rulesets.Objects.Drawables
 {
-    public abstract class DrawableHitObject<TObject, TJudgement> : Container
+    public abstract class DrawableHitObject : Container
-        where TObject : HitObject
-        where TJudgement : Judgement
     {
-        public event Action<DrawableHitObject<TObject, TJudgement>> OnJudgement;
+        public readonly HitObject HitObject;
-
-        public TObject HitObject;
 
         /// <summary>
         /// The colour used for various elements of this DrawableHitObject.
         /// </summary>
         public virtual Color4 AccentColour { get; set; }
 
+        protected DrawableHitObject(HitObject hitObject)
+        {
+            HitObject = hitObject;
+        }
+    }
+
+    public abstract class DrawableHitObject<TObject> : DrawableHitObject
+        where TObject : HitObject
+    {
+        public new readonly TObject HitObject;
+
+        protected DrawableHitObject(TObject hitObject)
+            : base(hitObject)
+        {
+            HitObject = hitObject;
+        }
+    }
+
+    public abstract class DrawableHitObject<TObject, TJudgement> : DrawableHitObject<TObject>
+        where TObject : HitObject
+        where TJudgement : Judgement
+    {
+        public event Action<DrawableHitObject<TObject, TJudgement>> OnJudgement;
+
         public override bool HandleInput => Interactive;
 
         public bool Interactive = true;
 
         public TJudgement Judgement;
 
-        protected abstract TJudgement CreateJudgement();
+        protected List<SampleChannel> Samples = new List<SampleChannel>();
 
-        protected abstract void UpdateState(ArmedState state);
+        protected DrawableHitObject(TObject hitObject)
+            : base(hitObject)
+        {
+        }
 
         private ArmedState state;
         public ArmedState State
@@ -59,8 +82,6 @@ namespace osu.Game.Rulesets.Objects.Drawables
             }
         }
 
-        protected List<SampleChannel> Samples = new List<SampleChannel>();
-
         protected void PlaySamples()
         {
             Samples.ForEach(s => s?.Play());
@@ -79,11 +100,6 @@ namespace osu.Game.Rulesets.Objects.Drawables
         /// </summary>
         public bool Judged => (Judgement?.Result ?? HitResult.None) != HitResult.None && (NestedHitObjects?.All(h => h.Judged) ?? true);
 
-        protected DrawableHitObject(TObject hitObject)
-        {
-            HitObject = hitObject;
-        }
-
         /// <summary>
         /// Process a hit of this hitobject. Carries out judgement.
         /// </summary>
@@ -176,5 +192,8 @@ namespace osu.Game.Rulesets.Objects.Drawables
             h.OnJudgement += d => OnJudgement?.Invoke(d);
             nestedHitObjects.Add(h);
         }
+
+        protected abstract TJudgement CreateJudgement();
+        protected abstract void UpdateState(ArmedState state);
     }
 }

osu.Game/Rulesets/Objects/HitObjectStartTimeComparer.cs

@@ -0,0 +1,55 @@
+// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Game.Rulesets.Objects.Drawables;
+
+namespace osu.Game.Rulesets.Objects
+{
+    /// <summary>
+    /// Compares two hit objects by their start time, falling back to creation order if their start time is equal.
+    /// </summary>
+    public class HitObjectStartTimeComparer : Drawable.CreationOrderDepthComparer
+    {
+        public override int Compare(Drawable x, Drawable y)
+        {
+            var hitObjectX = x as DrawableHitObject;
+            var hitObjectY = y as DrawableHitObject;
+
+            // If either of the two drawables are not hit objects, fall back to the base comparer
+            if ((hitObjectX ?? hitObjectY) == null)
+                return base.Compare(x, y);
+
+            // Compare by start time
+            int i = hitObjectX.HitObject.StartTime.CompareTo(hitObjectY.HitObject.StartTime);
+            if (i != 0)
+                return i;
+
+            return base.Compare(x, y);
+        }
+    }
+
+    /// <summary>
+    /// Compares two hit objects by their start time, falling back to creation order if their start time is equal.
+    /// This will compare the two hit objects in reverse order.
+    /// </summary>
+    public class HitObjectReverseStartTimeComparer : Drawable.ReverseCreationOrderDepthComparer
+    {
+        public override int Compare(Drawable x, Drawable y)
+        {
+            var hitObjectX = x as DrawableHitObject;
+            var hitObjectY = y as DrawableHitObject;
+
+            // If either of the two drawables are not hit objects, fall back to the base comparer
+            if ((hitObjectX ?? hitObjectY) == null)
+                return base.Compare(x, y);
+
+            // Compare by start time
+            int i = hitObjectY.HitObject.StartTime.CompareTo(hitObjectX.HitObject.StartTime);
+            if (i != 0)
+                return i;
+
+            return base.Compare(x, y);
+        }
+    }
+}