From 01ff1584c22de096f34ecf347fa27da79c9081b4 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Thu, 18 Jan 2018 21:06:47 +0900
Subject: [PATCH] Fix repeat points not following slider snaking correctly

---
 .../Objects/Drawables/DrawableRepeatPoint.cs         |  5 ++++-
 .../Objects/Drawables/DrawableSlider.cs              |  6 ++++--
 .../Objects/Drawables/ITrackSnaking.cs               | 12 ++++++++++++
 osu.Game.Rulesets.Osu/osu.Game.Rulesets.Osu.csproj   |  1 +
 4 files changed, 21 insertions(+), 3 deletions(-)
 create mode 100644 osu.Game.Rulesets.Osu/Objects/Drawables/ITrackSnaking.cs

diff --git a/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableRepeatPoint.cs b/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableRepeatPoint.cs
index f18d982bc0..7a74709e65 100644
--- a/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableRepeatPoint.cs
+++ b/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableRepeatPoint.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System;
+using System.Drawing.Imaging;
 using osu.Framework.Graphics;
 using osu.Game.Rulesets.Objects.Drawables;
 using OpenTK;
@@ -11,7 +12,7 @@
 
 namespace osu.Game.Rulesets.Osu.Objects.Drawables
 {
-    public class DrawableRepeatPoint : DrawableOsuHitObject
+    public class DrawableRepeatPoint : DrawableOsuHitObject, ITrackSnaking
     {
         private readonly RepeatPoint repeatPoint;
         private readonly DrawableSlider drawableSlider;
@@ -71,5 +72,7 @@ protected override void UpdateCurrentState(ArmedState state)
                     break;
             }
         }
+
+        public void UpdateSnakingPosition(Vector2 start, Vector2 end) => Position = repeatPoint.RepeatIndex / 2 == 0 ? end : start;
     }
 }
diff --git a/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs b/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs
index 6aa3268e5e..eb499b5da6 100644
--- a/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs
+++ b/osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs
@@ -20,7 +20,7 @@ public class DrawableSlider : DrawableOsuHitObject, IDrawableHitObjectWithProxie
 
         public readonly DrawableHitCircle InitialCircle;
 
-        private readonly List<ISliderProgress> components = new List<ISliderProgress>();
+        private readonly List<Drawable> components = new List<Drawable>();
 
         private readonly Container<DrawableSliderTick> ticks;
         private readonly Container<DrawableRepeatPoint> repeatPoints;
@@ -101,6 +101,7 @@ public DrawableSlider(Slider s)
                 };
 
                 repeatPoints.Add(drawableRepeatPoint);
+                components.Add(drawableRepeatPoint);
                 AddNested(drawableRepeatPoint);
             }
         }
@@ -126,7 +127,8 @@ protected override void Update()
             if (!InitialCircle.Judgements.Any(j => j.IsHit))
                 InitialCircle.Position = slider.Curve.PositionAt(progress);
 
-            foreach (var c in components) c.UpdateProgress(progress, repeat);
+            foreach (var c in components.OfType<ISliderProgress>()) c.UpdateProgress(progress, repeat);
+            foreach (var c in components.OfType<ITrackSnaking>()) c.UpdateSnakingPosition(slider.Curve.PositionAt(Body.SnakedStart ?? 0), slider.Curve.PositionAt(Body.SnakedEnd ?? 0));
             foreach (var t in ticks.Children) t.Tracking = Ball.Tracking;
         }
 
diff --git a/osu.Game.Rulesets.Osu/Objects/Drawables/ITrackSnaking.cs b/osu.Game.Rulesets.Osu/Objects/Drawables/ITrackSnaking.cs
new file mode 100644
index 0000000000..121df04483
--- /dev/null
+++ b/osu.Game.Rulesets.Osu/Objects/Drawables/ITrackSnaking.cs
@@ -0,0 +1,12 @@
+using OpenTK;
+
+namespace osu.Game.Rulesets.Osu.Objects.Drawables
+{
+    /// <summary>
+    /// A component which tracks the current end snaking position of a slider.
+    /// </summary>
+    public interface ITrackSnaking
+    {
+        void UpdateSnakingPosition(Vector2 start, Vector2 end);
+    }
+}
diff --git a/osu.Game.Rulesets.Osu/osu.Game.Rulesets.Osu.csproj b/osu.Game.Rulesets.Osu/osu.Game.Rulesets.Osu.csproj
index 7d6001359a..a59d4607df 100644
--- a/osu.Game.Rulesets.Osu/osu.Game.Rulesets.Osu.csproj
+++ b/osu.Game.Rulesets.Osu/osu.Game.Rulesets.Osu.csproj
@@ -71,6 +71,7 @@
     <Compile Include="Objects\Drawables\Connections\FollowPointRenderer.cs" />
     <Compile Include="Judgements\OsuJudgement.cs" />
     <Compile Include="Objects\Drawables\DrawableRepeatPoint.cs" />
+    <Compile Include="Objects\Drawables\ITrackSnaking.cs" />
     <Compile Include="Objects\Drawables\Pieces\ApproachCircle.cs" />
     <Compile Include="Objects\Drawables\Pieces\SpinnerBackground.cs" />
     <Compile Include="Objects\Drawables\Pieces\CirclePiece.cs" />