Factor out palpable obejct enumeration logic

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

@@ -5,6 +5,7 @@
 using System.Linq;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Objects;
 
 namespace osu.Game.Rulesets.Catch.Beatmaps
 {
@@ -38,5 +39,25 @@ public override IEnumerable<BeatmapStatistic> GetStatistics()
                 }
             };
         }
+
+        /// <summary>
+        /// Enumerate all <see cref="PalpableCatchHitObject"/>s, sorted by their start times.
+        /// </summary>
+        /// <remarks>
+        /// If multiple objects have the same start time, the ordering is preserved (it is a stable sorting).
+        /// </remarks>
+        public static IEnumerable<PalpableCatchHitObject> GetPalpableObjects(IEnumerable<HitObject> hitObjects)
+        {
+            return hitObjects.SelectMany(selectPalpableObjects).OrderBy(h => h.StartTime);
+
+            IEnumerable<PalpableCatchHitObject> selectPalpableObjects(HitObject h)
+            {
+                if (h is PalpableCatchHitObject palpable)
+                    yield return palpable;
+
+                foreach (var nested in h.NestedHitObjects.OfType<PalpableCatchHitObject>())
+                    yield return nested;
+            }
+        }
     }
 }

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

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
-using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Catch.Objects;
@@ -192,24 +191,9 @@ private static void applyOffset(ref float position, float amount)
 
         private static void initialiseHyperDash(IBeatmap beatmap)
         {
-            List<PalpableCatchHitObject> palpableObjects = new List<PalpableCatchHitObject>();
+            var palpableObjects = CatchBeatmap.GetPalpableObjects(beatmap.HitObjects)
-
+                                              .Where(h => h is Fruit || (h is Droplet && h is not TinyDroplet))
-            foreach (var currentObject in beatmap.HitObjects)
+                                              .ToArray();
-            {
-                if (currentObject is Fruit fruitObject)
-                    palpableObjects.Add(fruitObject);
-
-                if (currentObject is JuiceStream)
-                {
-                    foreach (var juice in currentObject.NestedHitObjects)
-                    {
-                        if (juice is PalpableCatchHitObject palpableObject && !(juice is TinyDroplet))
-                            palpableObjects.Add(palpableObject);
-                    }
-                }
-            }
-
-            palpableObjects = palpableObjects.OrderBy(h => h.StartTime).ToList();
 
             double halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.Difficulty) / 2;
 
@@ -221,7 +205,7 @@ private static void initialiseHyperDash(IBeatmap beatmap)
             int lastDirection = 0;
             double lastExcess = halfCatcherWidth;
 
-            for (int i = 0; i < palpableObjects.Count - 1; i++)
+            for (int i = 0; i < palpableObjects.Length - 1; i++)
             {
                 var currentObject = palpableObjects[i];
                 var nextObject = palpableObjects[i + 1];

osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyCalculator.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Catch.Beatmaps;
 using osu.Game.Rulesets.Catch.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Catch.Difficulty.Skills;
 using osu.Game.Rulesets.Catch.Mods;
@@ -54,13 +55,10 @@ protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(I
             List<DifficultyHitObject> objects = new List<DifficultyHitObject>();
 
             // In 2B beatmaps, it is possible that a normal Fruit is placed in the middle of a JuiceStream.
-            foreach (var hitObject in beatmap.HitObjects
+            foreach (var hitObject in CatchBeatmap.GetPalpableObjects(beatmap.HitObjects))
-                                             .SelectMany(obj => obj is JuiceStream stream ? stream.NestedHitObjects.AsEnumerable() : new[] { obj })
-                                             .Cast<CatchHitObject>()
-                                             .OrderBy(x => x.StartTime))
             {
                 // We want to only consider fruits that contribute to the combo.
-                if (hitObject is BananaShower || hitObject is TinyDroplet)
+                if (hitObject is Banana || hitObject is TinyDroplet)
                     continue;
 
                 if (lastObject != null)