Implement local scrolling hit object container

osu.Game/Rulesets/UI/Scrolling/Algorithms/LocalScrollingAlgorithm.cs

@@ -0,0 +1,79 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu-framework/master/LICENCE
+
+using System.Collections.Generic;
+using osu.Framework.Lists;
+using osu.Game.Rulesets.Objects.Drawables;
+using osu.Game.Rulesets.Objects.Types;
+using osu.Game.Rulesets.Timing;
+using OpenTK;
+
+namespace osu.Game.Rulesets.UI.Scrolling.Algorithms
+{
+    public class LocalScrollingAlgorithm : IScrollingAlgorithm
+    {
+        private readonly Dictionary<DrawableHitObject, double> hitObjectPositions = new Dictionary<DrawableHitObject, double>();
+
+        private readonly SortedList<MultiplierControlPoint> controlPoints;
+
+        public LocalScrollingAlgorithm(SortedList<MultiplierControlPoint> controlPoints)
+        {
+            this.controlPoints = controlPoints;
+        }
+
+        public void ComputeInitialStates(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double timeRange, Vector2 length)
+        {
+            foreach (var obj in hitObjects)
+            {
+                var controlPoint = controlPointAt(obj.HitObject.StartTime);
+
+                obj.LifetimeStart = obj.HitObject.StartTime - timeRange / controlPoint.Multiplier;
+                obj.LifetimeEnd = ((obj as IHasEndTime)?.EndTime ?? obj.HitObject.StartTime) + timeRange / controlPoint.Multiplier;
+            }
+        }
+
+        public void ComputePositions(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double currentTime, double timeRange, Vector2 length)
+        {
+            foreach (var obj in hitObjects)
+            {
+                var controlPoint = controlPointAt(obj.HitObject.StartTime);
+
+                var position = (obj.HitObject.StartTime - currentTime) * controlPoint.Multiplier / timeRange;
+
+                switch (direction)
+                {
+                    case ScrollingDirection.Up:
+                        obj.Y = (float)(position * length.Y);
+                        break;
+                    case ScrollingDirection.Down:
+                        obj.Y = (float)(-position * length.Y);
+                        break;
+                    case ScrollingDirection.Left:
+                        obj.X = (float)(position * length.X);
+                        break;
+                    case ScrollingDirection.Right:
+                        obj.X = (float)(-position * length.X);
+                        break;
+                }
+            }
+        }
+
+        private readonly MultiplierControlPoint searchPoint = new MultiplierControlPoint();
+        private MultiplierControlPoint controlPointAt(double time)
+        {
+            if (controlPoints.Count == 0)
+                return new MultiplierControlPoint(double.NegativeInfinity);
+
+            if (time < controlPoints[0].StartTime)
+                return controlPoints[0];
+
+            searchPoint.StartTime = time;
+            int index = controlPoints.BinarySearch(searchPoint);
+
+            if (index < 0)
+                index = ~index - 1;
+
+            return controlPoints[index];
+        }
+    }
+}

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

@@ -0,0 +1,17 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu-framework/master/LICENCE
+
+using osu.Game.Rulesets.UI.Scrolling.Algorithms;
+
+namespace osu.Game.Rulesets.UI.Scrolling
+{
+    public class LocalScrollingHitObjectContainer : ScrollingHitObjectContainer
+    {
+        public LocalScrollingHitObjectContainer(ScrollingDirection direction)
+            : base(direction)
+        {
+        }
+
+        protected override IScrollingAlgorithm CreateScrollingAlgorithm() => new LocalScrollingAlgorithm(ControlPoints);
+    }
+}

osu.Game/osu.Game.csproj

@@ -318,7 +318,9 @@
     <Compile Include="Rulesets\UI\HitObjectContainer.cs" />
     <Compile Include="Rulesets\UI\Scrolling\Algorithms\GlobalScrollingAlgorithm.cs" />
     <Compile Include="Rulesets\UI\Scrolling\Algorithms\IScrollingAlgorithm.cs" />
+    <Compile Include="Rulesets\UI\Scrolling\Algorithms\LocalScrollingAlgorithm.cs" />
     <Compile Include="Rulesets\UI\Scrolling\GlobalScrollingHitObjectContainer.cs" />
+    <Compile Include="Rulesets\UI\Scrolling\LocalScrollingHitObjectContainer.cs" />
     <Compile Include="Rulesets\UI\Scrolling\ScrollingDirection.cs" />
     <Compile Include="Rulesets\UI\Scrolling\ScrollingHitObjectContainer.cs" />
     <Compile Include="Rulesets\UI\Scrolling\ScrollingPlayfield.cs" />