Share fade in logic with repeats

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

@@ -1,9 +1,34 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.ControlPoints;
+using osu.Game.Rulesets.Scoring;
+
 namespace osu.Game.Rulesets.Osu.Objects
 {
-    public class SliderEndCircle : HitCircle
+    /// <summary>
+    /// A hitcircle which is at the end of a slider path (either repeat or final tail).
+    /// </summary>
+    public abstract class SliderEndCircle : HitCircle
     {
+        public int RepeatIndex { get; set; }
+        public double SpanDuration { get; set; }
+
+        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+        {
+            base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
+
+            // Out preempt should be one span early to give the user ample warning.
+            TimePreempt += SpanDuration;
+
+            // We want to show the first RepeatPoint as the TimePreempt dictates but on short (and possibly fast) sliders
+            // we may need to cut down this time on following RepeatPoints to only show up to two RepeatPoints at any given time.
+            if (RepeatIndex > 0)
+                TimePreempt = Math.Min(SpanDuration * 2, TimePreempt);
+        }
+
+        protected override HitWindows CreateHitWindows() => HitWindows.Empty;
     }
 }