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