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94 lines
3.6 KiB
C#
94 lines
3.6 KiB
C#
// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
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// See the LICENCE file in the repository root for full licence text.
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using osu.Framework.Lists;
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using osu.Game.Rulesets.Timing;
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using osuTK;
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namespace osu.Game.Rulesets.UI.Scrolling.Algorithms
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{
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public class OverlappingScrollAlgorithm : IScrollAlgorithm
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{
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private readonly MultiplierControlPoint searchPoint;
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private readonly SortedList<MultiplierControlPoint> controlPoints;
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public OverlappingScrollAlgorithm(SortedList<MultiplierControlPoint> controlPoints)
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{
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this.controlPoints = controlPoints;
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searchPoint = new MultiplierControlPoint();
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}
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public double GetDisplayStartTime(double time, double timeRange)
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{
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// The total amount of time that the hitobject will remain visible within the timeRange, which decreases as the speed multiplier increases
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double visibleDuration = timeRange / controlPointAt(time).Multiplier;
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return time - visibleDuration;
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}
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public float GetLength(double startTime, double endTime, double timeRange, float scrollLength)
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{
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// At the hitobject's end time, the hitobject will be positioned such that its end rests at the origin.
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// This results in a negative-position value, and the absolute of it indicates the length of the hitobject.
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return -PositionAt(startTime, endTime, timeRange, scrollLength);
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}
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public float PositionAt(double time, double currentTime, double timeRange, float scrollLength)
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=> (float)((time - currentTime) / timeRange * controlPointAt(time).Multiplier * scrollLength);
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public double TimeAt(float position, double currentTime, double timeRange, float scrollLength)
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{
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// Find the control point relating to the position.
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// Note: Due to velocity adjustments, overlapping control points will provide multiple valid time values for a single position
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// As such, this operation provides unexpected results by using the latter of the control points.
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int i = 0;
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float pos = 0;
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for (; i < controlPoints.Count; i++)
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{
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float lastPos = pos;
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pos = PositionAt(controlPoints[i].StartTime, currentTime, timeRange, scrollLength);
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if (pos > position)
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{
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i--;
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pos = lastPos;
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break;
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}
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}
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i = MathHelper.Clamp(i, 0, controlPoints.Count - 1);
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return controlPoints[i].StartTime + (position - pos) * timeRange / controlPoints[i].Multiplier / scrollLength;
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}
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public void Reset()
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{
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}
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/// <summary>
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/// Finds the <see cref="MultiplierControlPoint"/> which affects the speed of hitobjects at a specific time.
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/// </summary>
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/// <param name="time">The time which the <see cref="MultiplierControlPoint"/> should affect.</param>
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/// <returns>The <see cref="MultiplierControlPoint"/>.</returns>
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private MultiplierControlPoint controlPointAt(double time)
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{
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if (controlPoints.Count == 0)
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return new MultiplierControlPoint(double.NegativeInfinity);
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if (time < controlPoints[0].StartTime)
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return controlPoints[0];
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searchPoint.StartTime = time;
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int index = controlPoints.BinarySearch(searchPoint);
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if (index < 0)
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index = ~index - 1;
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return controlPoints[index];
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}
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}
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}
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