diff --git a/osu.Game/Rulesets/UI/Scrolling/Visualisers/OverlappingSpeedChangeVisualiser.cs b/osu.Game/Rulesets/UI/Scrolling/Visualisers/OverlappingSpeedChangeVisualiser.cs
index 6045ab50e7..e45e391dbc 100644
--- a/osu.Game/Rulesets/UI/Scrolling/Visualisers/OverlappingSpeedChangeVisualiser.cs
+++ b/osu.Game/Rulesets/UI/Scrolling/Visualisers/OverlappingSpeedChangeVisualiser.cs
@@ -80,10 +80,12 @@ namespace osu.Game.Rulesets.UI.Scrolling.Visualisers
}
///
- /// Computes the position of a at a point in time.
+ /// Computes the position of a at a point in time.
+ ///
/// At t < startTime, position > 0.
/// At t = startTime, position = 0.
/// At t > startTime, position < 0.
+ ///
///
/// The .
/// The time to find the position of at.
diff --git a/osu.Game/Rulesets/UI/Scrolling/Visualisers/SequentialSpeedChangeVisualiser.cs b/osu.Game/Rulesets/UI/Scrolling/Visualisers/SequentialSpeedChangeVisualiser.cs
index 708a2f173b..c8725fab56 100644
--- a/osu.Game/Rulesets/UI/Scrolling/Visualisers/SequentialSpeedChangeVisualiser.cs
+++ b/osu.Game/Rulesets/UI/Scrolling/Visualisers/SequentialSpeedChangeVisualiser.cs
@@ -25,23 +25,25 @@ namespace osu.Game.Rulesets.UI.Scrolling.Visualisers
{
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 diff = positionAt(endTime.EndTime, timeRange) - startPosition;
+ var hitObjectLength = positionAt(endTime.EndTime, timeRange) - startPosition;
switch (direction)
{
case ScrollingDirection.Up:
case ScrollingDirection.Down:
- obj.Height = (float)(diff * length.Y);
+ obj.Height = (float)(hitObjectLength * length.Y);
break;
case ScrollingDirection.Left:
case ScrollingDirection.Right:
- obj.Width = (float)(diff * length.X);
+ obj.Width = (float)(hitObjectLength * length.X);
break;
}
}
@@ -49,6 +51,8 @@ namespace osu.Game.Rulesets.UI.Scrolling.Visualisers
if (obj.HasNestedHitObjects)
{
ComputeInitialStates(obj.NestedHitObjects, direction, timeRange, length);
+
+ // Nested hitobjects don't need to scroll, but they do need accurate positions
ComputePositions(obj.NestedHitObjects, direction, obj.HitObject.StartTime, timeRange, length);
}
}
@@ -80,21 +84,38 @@ namespace osu.Game.Rulesets.UI.Scrolling.Visualisers
}
}
+ ///
+ /// 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.
+ ///
+ /// The time to find the position at.
+ /// The amount of time visualised by the scrolling area.
+ /// A positive value indicating the position at .
private double positionAt(double time, double 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;
- length += Math.Min(currentDuration, time - current.StartTime) * current.Multiplier / timeRange;
+ // 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;