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Merge pull request #3706 from smoogipoo/no-drawable-speedchangevis

Make scroll algorithms not tied to drawable hitobjects
This commit is contained in:
Dean Herbert 2018-11-14 13:31:35 +09:00 committed by GitHub
commit 1b936dfc17
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GPG Key ID: 4AEE18F83AFDEB23
14 changed files with 304 additions and 362 deletions

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@ -23,7 +23,7 @@ namespace osu.Game.Rulesets.Catch.UI
protected override bool UserScrollSpeedAdjustment => false;
protected override SpeedChangeVisualisationMethod VisualisationMethod => SpeedChangeVisualisationMethod.Constant;
protected override ScrollVisualisationMethod VisualisationMethod => ScrollVisualisationMethod.Constant;
public CatchPlayfield(BeatmapDifficulty difficulty, Func<CatchHitObject, DrawableHitObject<CatchHitObject>> getVisualRepresentation)
{

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@ -41,7 +41,7 @@ namespace osu.Game.Rulesets.Taiko.UI
protected override bool UserScrollSpeedAdjustment => false;
protected override SpeedChangeVisualisationMethod VisualisationMethod => SpeedChangeVisualisationMethod.Overlapping;
protected override ScrollVisualisationMethod VisualisationMethod => ScrollVisualisationMethod.Overlapping;
private readonly Container<HitExplosion> hitExplosionContainer;
private readonly Container<KiaiHitExplosion> kiaiExplosionContainer;

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@ -114,11 +114,11 @@ namespace osu.Game.Tests.Visual
private class TestPlayfield : ScrollingPlayfield
{
public new readonly ScrollingDirection Direction;
public new ScrollingDirection Direction => base.Direction;
public TestPlayfield(ScrollingDirection direction)
{
Direction = direction;
base.Direction.Value = direction;
Padding = new MarginPadding(2);

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@ -5,7 +5,7 @@ using System.ComponentModel;
namespace osu.Game.Configuration
{
public enum SpeedChangeVisualisationMethod
public enum ScrollVisualisationMethod
{
[Description("Sequential")]
Sequential,

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@ -0,0 +1,24 @@
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
namespace osu.Game.Rulesets.UI.Scrolling.Algorithms
{
public class ConstantScrollAlgorithm : IScrollAlgorithm
{
public double GetDisplayStartTime(double time, double timeRange) => time - timeRange;
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)
=> (float)((time - currentTime) / timeRange * scrollLength);
public void Reset()
{
}
}
}

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@ -0,0 +1,44 @@
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
namespace osu.Game.Rulesets.UI.Scrolling.Algorithms
{
public interface IScrollAlgorithm
{
/// <summary>
/// Given a point in time, computes the time at which it enters the time range.
/// </summary>
/// <remarks>
/// E.g. For a constant time range of 5000ms, the time at which t=7000ms enters the time range is 2000ms.
/// </remarks>
/// <param name="time">The point in time.</param>
/// <param name="timeRange">The amount of visible time.</param>
/// <returns>The time at which <paramref name="time"/> enters <see cref="timeRange"/>.</returns>
double GetDisplayStartTime(double time, double timeRange);
/// <summary>
/// Computes the spatial length within a start and end time.
/// </summary>
/// <param name="startTime">The start time.</param>
/// <param name="endTime">The end time.</param>
/// <param name="timeRange">The amount of visible time.</param>
/// <param name="scrollLength">The absolute spatial length through <see cref="timeRange"/>.</param>
/// <returns>The absolute spatial length.</returns>
float GetLength(double startTime, double endTime, double timeRange, float scrollLength);
/// <summary>
/// Given the current time, computes the spatial position of a point in time.
/// </summary>
/// <param name="time">The time to compute the spatial position of.</param>
/// <param name="currentTime">The current time.</param>
/// <param name="timeRange">The amount of visible time.</param>
/// <param name="scrollLength">The absolute spatial length through <see cref="timeRange"/>.</param>
/// <returns>The absolute spatial position.</returns>
float PositionAt(double time, double currentTime, double timeRange, float scrollLength);
/// <summary>
/// Resets this <see cref="IScrollAlgorithm"/> to a default state.
/// </summary>
void Reset();
}
}

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@ -0,0 +1,65 @@
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using osu.Framework.Lists;
using osu.Game.Rulesets.Timing;
namespace osu.Game.Rulesets.UI.Scrolling.Algorithms
{
public class OverlappingScrollAlgorithm : IScrollAlgorithm
{
private readonly MultiplierControlPoint searchPoint;
private readonly SortedList<MultiplierControlPoint> controlPoints;
public OverlappingScrollAlgorithm(SortedList<MultiplierControlPoint> controlPoints)
{
this.controlPoints = controlPoints;
searchPoint = new MultiplierControlPoint();
}
public double GetDisplayStartTime(double time, double timeRange)
{
// The total amount of time that the hitobject will remain visible within the timeRange, which decreases as the speed multiplier increases
double visibleDuration = timeRange / controlPointAt(time).Multiplier;
return time - 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)
=> (float)((time - currentTime) / timeRange * controlPointAt(time).Multiplier * scrollLength);
public void Reset()
{
}
/// <summary>
/// Finds the <see cref="MultiplierControlPoint"/> which affects the speed of hitobjects at a specific time.
/// </summary>
/// <param name="time">The time which the <see cref="MultiplierControlPoint"/> should affect.</param>
/// <returns>The <see cref="MultiplierControlPoint"/>.</returns>
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];
}
}
}

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@ -0,0 +1,87 @@
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System;
using System.Collections.Generic;
using osu.Game.Rulesets.Timing;
namespace osu.Game.Rulesets.UI.Scrolling.Algorithms
{
public class SequentialScrollAlgorithm : IScrollAlgorithm
{
private readonly Dictionary<double, double> positionCache;
private readonly IReadOnlyList<MultiplierControlPoint> controlPoints;
public SequentialScrollAlgorithm(IReadOnlyList<MultiplierControlPoint> controlPoints)
{
this.controlPoints = controlPoints;
positionCache = new Dictionary<double, double>();
}
public double GetDisplayStartTime(double time, double timeRange) => time - timeRange - 1000;
public float GetLength(double startTime, double endTime, double timeRange, float scrollLength)
{
var objectLength = relativePositionAtCached(endTime, timeRange) - relativePositionAtCached(startTime, timeRange);
return (float)(objectLength * scrollLength);
}
public float PositionAt(double time, double currentTime, double timeRange, float scrollLength)
{
// Caching is not used here as currentTime is unlikely to have been previously cached
double timelinePosition = relativePositionAt(currentTime, timeRange);
return (float)((relativePositionAtCached(time, timeRange) - timelinePosition) * scrollLength);
}
private double relativePositionAtCached(double time, double timeRange)
{
if (!positionCache.TryGetValue(time, out double existing))
positionCache[time] = existing = relativePositionAt(time, timeRange);
return existing;
}
public void Reset() => positionCache.Clear();
/// <summary>
/// Finds the position which corresponds to a point in time.
/// This is a non-linear operation that depends on all the control points up to and including the one active at the time value.
/// </summary>
/// <param name="time">The time to find the position at.</param>
/// <param name="timeRange">The amount of time visualised by the scrolling area.</param>
/// <returns>A positive value indicating the position at <paramref name="time"/>.</returns>
private double relativePositionAt(double time, double timeRange)
{
if (controlPoints.Count == 0)
return time / timeRange;
double length = 0;
// We need to consider all timing points until the specified time and not just the currently-active one,
// since each timing point individually affects the positions of _all_ hitobjects after its start time
for (int i = 0; i < controlPoints.Count; i++)
{
var current = controlPoints[i];
var next = i < controlPoints.Count - 1 ? controlPoints[i + 1] : null;
// We don't need to consider any control points beyond the current time, since it will not yet
// affect any hitobjects
if (i > 0 && current.StartTime > time)
continue;
// Duration of the current control point
var currentDuration = (next?.StartTime ?? double.PositiveInfinity) - current.StartTime;
// We want to consider the minimal amount of time that this control point has affected,
// which may be either its duration, or the amount of time that has passed within it
var durationInCurrent = Math.Min(currentDuration, time - current.StartTime);
// Figure out how much of the time range the duration represents, and adjust it by the speed multiplier
length += durationInCurrent / timeRange * current.Multiplier;
}
return length;
}
}
}

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@ -7,8 +7,9 @@ using osu.Framework.Graphics;
using osu.Framework.Lists;
using osu.Game.Configuration;
using osu.Game.Rulesets.Objects.Drawables;
using osu.Game.Rulesets.Objects.Types;
using osu.Game.Rulesets.Timing;
using osu.Game.Rulesets.UI.Scrolling.Visualisers;
using osu.Game.Rulesets.UI.Scrolling.Algorithms;
namespace osu.Game.Rulesets.UI.Scrolling
{
@ -30,11 +31,11 @@ namespace osu.Game.Rulesets.UI.Scrolling
public readonly Bindable<ScrollingDirection> Direction = new Bindable<ScrollingDirection>();
private readonly IScrollAlgorithm algorithm;
private Cached initialStateCache = new Cached();
private readonly ISpeedChangeVisualiser speedChangeVisualiser;
public ScrollingHitObjectContainer(SpeedChangeVisualisationMethod visualisationMethod)
public ScrollingHitObjectContainer(ScrollVisualisationMethod visualisationMethod)
{
RelativeSizeAxes = Axes.Both;
@ -43,14 +44,14 @@ namespace osu.Game.Rulesets.UI.Scrolling
switch (visualisationMethod)
{
case SpeedChangeVisualisationMethod.Sequential:
speedChangeVisualiser = new SequentialSpeedChangeVisualiser(ControlPoints);
case ScrollVisualisationMethod.Sequential:
algorithm = new SequentialScrollAlgorithm(ControlPoints);
break;
case SpeedChangeVisualisationMethod.Overlapping:
speedChangeVisualiser = new OverlappingSpeedChangeVisualiser(ControlPoints);
case ScrollVisualisationMethod.Overlapping:
algorithm = new OverlappingScrollAlgorithm(ControlPoints);
break;
case SpeedChangeVisualisationMethod.Constant:
speedChangeVisualiser = new ConstantSpeedChangeVisualiser();
case ScrollVisualisationMethod.Constant:
algorithm = new ConstantScrollAlgorithm();
break;
}
}
@ -91,23 +92,87 @@ namespace osu.Game.Rulesets.UI.Scrolling
return base.Invalidate(invalidation, source, shallPropagate);
}
private float scrollLength;
protected override void Update()
{
base.Update();
if (!initialStateCache.IsValid)
{
speedChangeVisualiser.ComputeInitialStates(Objects, Direction, TimeRange, DrawSize);
switch (Direction.Value)
{
case ScrollingDirection.Up:
case ScrollingDirection.Down:
scrollLength = DrawSize.Y;
break;
default:
scrollLength = DrawSize.X;
break;
}
algorithm.Reset();
foreach (var obj in Objects)
computeInitialStateRecursive(obj);
initialStateCache.Validate();
}
}
private void computeInitialStateRecursive(DrawableHitObject hitObject)
{
hitObject.LifetimeStart = algorithm.GetDisplayStartTime(hitObject.HitObject.StartTime, TimeRange);
if (hitObject.HitObject is IHasEndTime endTime)
{
switch (Direction.Value)
{
case ScrollingDirection.Up:
case ScrollingDirection.Down:
hitObject.Height = algorithm.GetLength(hitObject.HitObject.StartTime, endTime.EndTime, TimeRange, scrollLength);
break;
case ScrollingDirection.Left:
case ScrollingDirection.Right:
hitObject.Width = algorithm.GetLength(hitObject.HitObject.StartTime, endTime.EndTime, TimeRange, scrollLength);
break;
}
}
foreach (var obj in hitObject.NestedHitObjects)
{
computeInitialStateRecursive(obj);
// Nested hitobjects don't need to scroll, but they do need accurate positions
updatePosition(obj, hitObject.HitObject.StartTime);
}
}
protected override void UpdateAfterChildrenLife()
{
base.UpdateAfterChildrenLife();
// We need to calculate this as soon as possible after lifetimes so that hitobjects get the final say in their positions
speedChangeVisualiser.UpdatePositions(AliveObjects, Direction, Time.Current, TimeRange, DrawSize);
// We need to calculate hitobject positions as soon as possible after lifetimes so that hitobjects get the final say in their positions
foreach (var obj in AliveObjects)
updatePosition(obj, Time.Current);
}
private void updatePosition(DrawableHitObject hitObject, double currentTime)
{
switch (Direction.Value)
{
case ScrollingDirection.Up:
hitObject.Y = algorithm.PositionAt(hitObject.HitObject.StartTime, currentTime, TimeRange, scrollLength);
break;
case ScrollingDirection.Down:
hitObject.Y = -algorithm.PositionAt(hitObject.HitObject.StartTime, currentTime, TimeRange, scrollLength);
break;
case ScrollingDirection.Left:
hitObject.X = algorithm.PositionAt(hitObject.HitObject.StartTime, currentTime, TimeRange, scrollLength);
break;
case ScrollingDirection.Right:
hitObject.X = -algorithm.PositionAt(hitObject.HitObject.StartTime, currentTime, TimeRange, scrollLength);
break;
}
}
}
}

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@ -63,7 +63,7 @@ namespace osu.Game.Rulesets.UI.Scrolling
/// </summary>
protected readonly Bindable<ScrollingDirection> Direction = new Bindable<ScrollingDirection>();
protected virtual SpeedChangeVisualisationMethod VisualisationMethod => SpeedChangeVisualisationMethod.Sequential;
protected virtual ScrollVisualisationMethod VisualisationMethod => ScrollVisualisationMethod.Sequential;
[BackgroundDependencyLoader]
private void load()

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@ -1,67 +0,0 @@
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System.Collections.Generic;
using osu.Game.Rulesets.Objects.Drawables;
using osu.Game.Rulesets.Objects.Types;
using OpenTK;
namespace osu.Game.Rulesets.UI.Scrolling.Visualisers
{
public class ConstantSpeedChangeVisualiser : ISpeedChangeVisualiser
{
public void ComputeInitialStates(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double timeRange, Vector2 length)
{
foreach (var obj in hitObjects)
{
obj.LifetimeStart = obj.HitObject.StartTime - timeRange;
if (obj.HitObject is IHasEndTime endTime)
{
var hitObjectLength = (endTime.EndTime - obj.HitObject.StartTime) / timeRange;
switch (direction)
{
case ScrollingDirection.Up:
case ScrollingDirection.Down:
obj.Height = (float)(hitObjectLength * length.Y);
break;
case ScrollingDirection.Left:
case ScrollingDirection.Right:
obj.Width = (float)(hitObjectLength * length.X);
break;
}
}
ComputeInitialStates(obj.NestedHitObjects, direction, timeRange, length);
// Nested hitobjects don't need to scroll, but they do need accurate positions
UpdatePositions(obj.NestedHitObjects, direction, obj.HitObject.StartTime, timeRange, length);
}
}
public void UpdatePositions(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double currentTime, double timeRange, Vector2 length)
{
foreach (var obj in hitObjects)
{
var position = (obj.HitObject.StartTime - currentTime) / 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;
}
}
}
}
}

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@ -1,32 +0,0 @@
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System.Collections.Generic;
using osu.Game.Rulesets.Objects.Drawables;
using OpenTK;
namespace osu.Game.Rulesets.UI.Scrolling.Visualisers
{
public interface ISpeedChangeVisualiser
{
/// <summary>
/// Computes the states of <see cref="DrawableHitObject"/>s that remain constant while scrolling, such as lifetime and spatial length.
/// This is invoked once whenever <paramref name="timeRange"/> or <paramref name="length"/> changes.
/// </summary>
/// <param name="hitObjects">The <see cref="DrawableHitObject"/>s whose states should be computed.</param>
/// <param name="direction">The scrolling direction.</param>
/// <param name="timeRange">The duration required to scroll through one length of the screen before any speed adjustments.</param>
/// <param name="length">The length of the screen that is scrolled through.</param>
void ComputeInitialStates(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double timeRange, Vector2 length);
/// <summary>
/// Updates the positions of <see cref="DrawableHitObject"/>s, depending on the current time. This is invoked once per frame.
/// </summary>
/// <param name="hitObjects">The <see cref="DrawableHitObject"/>s whose positions should be computed.</param>
/// <param name="direction">The scrolling direction.</param>
/// <param name="currentTime">The current time.</param>
/// <param name="timeRange">The duration required to scroll through one length of the screen before any speed adjustments.</param>
/// <param name="length">The length of the screen that is scrolled through.</param>
void UpdatePositions(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double currentTime, double timeRange, Vector2 length);
}
}

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@ -1,120 +0,0 @@
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/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.Visualisers
{
public class OverlappingSpeedChangeVisualiser : ISpeedChangeVisualiser
{
private readonly SortedList<MultiplierControlPoint> controlPoints;
public OverlappingSpeedChangeVisualiser(SortedList<MultiplierControlPoint> controlPoints)
{
this.controlPoints = controlPoints;
}
public void ComputeInitialStates(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double timeRange, Vector2 length)
{
foreach (var obj in hitObjects)
{
// The total amount of time that the hitobject will remain visible within the timeRange, which decreases as the speed multiplier increases
double visibleDuration = timeRange / controlPointAt(obj.HitObject.StartTime).Multiplier;
obj.LifetimeStart = obj.HitObject.StartTime - visibleDuration;
if (obj.HitObject is IHasEndTime endTime)
{
// 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.
var hitObjectLength = -hitObjectPositionAt(obj, endTime.EndTime, timeRange);
switch (direction)
{
case ScrollingDirection.Up:
case ScrollingDirection.Down:
obj.Height = (float)(hitObjectLength * length.Y);
break;
case ScrollingDirection.Left:
case ScrollingDirection.Right:
obj.Width = (float)(hitObjectLength * length.X);
break;
}
}
ComputeInitialStates(obj.NestedHitObjects, direction, timeRange, length);
// Nested hitobjects don't need to scroll, but they do need accurate positions
UpdatePositions(obj.NestedHitObjects, direction, obj.HitObject.StartTime, timeRange, length);
}
}
public void UpdatePositions(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double currentTime, double timeRange, Vector2 length)
{
foreach (var obj in hitObjects)
{
var position = hitObjectPositionAt(obj, currentTime, 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;
}
}
}
/// <summary>
/// Computes the position of a <see cref="DrawableHitObject"/> at a point in time.
/// <para>
/// At t &lt; startTime, position &gt; 0. <br />
/// At t = startTime, position = 0. <br />
/// At t &gt; startTime, position &lt; 0.
/// </para>
/// </summary>
/// <param name="obj">The <see cref="DrawableHitObject"/>.</param>
/// <param name="time">The time to find the position of <paramref name="obj"/> at.</param>
/// <param name="timeRange">The amount of time visualised by the scrolling area.</param>
/// <returns>The position of <paramref name="obj"/> in the scrolling area at time = <paramref name="time"/>.</returns>
private double hitObjectPositionAt(DrawableHitObject obj, double time, double timeRange)
=> (obj.HitObject.StartTime - time) / timeRange * controlPointAt(obj.HitObject.StartTime).Multiplier;
private readonly MultiplierControlPoint searchPoint = new MultiplierControlPoint();
/// <summary>
/// Finds the <see cref="MultiplierControlPoint"/> which affects the speed of hitobjects at a specific time.
/// </summary>
/// <param name="time">The time which the <see cref="MultiplierControlPoint"/> should affect.</param>
/// <returns>The <see cref="MultiplierControlPoint"/>.</returns>
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];
}
}
}

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@ -1,124 +0,0 @@
// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
using System;
using System.Collections.Generic;
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.Visualisers
{
public class SequentialSpeedChangeVisualiser : ISpeedChangeVisualiser
{
private readonly Dictionary<DrawableHitObject, double> hitObjectPositions = new Dictionary<DrawableHitObject, double>();
private readonly IReadOnlyList<MultiplierControlPoint> controlPoints;
public SequentialSpeedChangeVisualiser(IReadOnlyList<MultiplierControlPoint> controlPoints)
{
this.controlPoints = controlPoints;
}
public void ComputeInitialStates(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double timeRange, Vector2 length)
{
foreach (var obj in hitObjects)
{
// To reduce iterations when updating hitobject positions later on, their initial positions are cached
var startPosition = hitObjectPositions[obj] = positionAt(obj.HitObject.StartTime, timeRange);
// Todo: This is approximate and will be incorrect in the case of extreme speed changes
obj.LifetimeStart = obj.HitObject.StartTime - timeRange - 1000;
if (obj.HitObject is IHasEndTime endTime)
{
var hitObjectLength = positionAt(endTime.EndTime, timeRange) - startPosition;
switch (direction)
{
case ScrollingDirection.Up:
case ScrollingDirection.Down:
obj.Height = (float)(hitObjectLength * length.Y);
break;
case ScrollingDirection.Left:
case ScrollingDirection.Right:
obj.Width = (float)(hitObjectLength * length.X);
break;
}
}
ComputeInitialStates(obj.NestedHitObjects, direction, timeRange, length);
// Nested hitobjects don't need to scroll, but they do need accurate positions
UpdatePositions(obj.NestedHitObjects, direction, obj.HitObject.StartTime, timeRange, length);
}
}
public void UpdatePositions(IEnumerable<DrawableHitObject> hitObjects, ScrollingDirection direction, double currentTime, double timeRange, Vector2 length)
{
var timelinePosition = positionAt(currentTime, timeRange);
foreach (var obj in hitObjects)
{
var finalPosition = hitObjectPositions[obj] - timelinePosition;
switch (direction)
{
case ScrollingDirection.Up:
obj.Y = (float)(finalPosition * length.Y);
break;
case ScrollingDirection.Down:
obj.Y = (float)(-finalPosition * length.Y);
break;
case ScrollingDirection.Left:
obj.X = (float)(finalPosition * length.X);
break;
case ScrollingDirection.Right:
obj.X = (float)(-finalPosition * length.X);
break;
}
}
}
/// <summary>
/// Finds the position which corresponds to a point in time.
/// This is a non-linear operation that depends on all the control points up to and including the one active at the time value.
/// </summary>
/// <param name="time">The time to find the position at.</param>
/// <param name="timeRange">The amount of time visualised by the scrolling area.</param>
/// <returns>A positive value indicating the position at <paramref name="time"/>.</returns>
private double positionAt(double time, double timeRange)
{
if (controlPoints.Count == 0)
return time / timeRange;
double length = 0;
// We need to consider all timing points until the specified time and not just the currently-active one,
// since each timing point individually affects the positions of _all_ hitobjects after its start time
for (int i = 0; i < controlPoints.Count; i++)
{
var current = controlPoints[i];
var next = i < controlPoints.Count - 1 ? controlPoints[i + 1] : null;
// We don't need to consider any control points beyond the current time, since it will not yet
// affect any hitobjects
if (i > 0 && current.StartTime > time)
continue;
// Duration of the current control point
var currentDuration = (next?.StartTime ?? double.PositiveInfinity) - current.StartTime;
// We want to consider the minimal amount of time that this control point has affected,
// which may be either its duration, or the amount of time that has passed within it
var durationInCurrent = Math.Min(currentDuration, time - current.StartTime);
// Figure out how much of the time range the duration represents, and adjust it by the speed multiplier
length += durationInCurrent / timeRange * current.Multiplier;
}
return length;
}
}
}