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Add circle arc segments

This commit is contained in:
OliBomby 2023-12-07 00:26:13 +01:00
parent 22287f3a7f
commit 1930476192

View File

@ -3,6 +3,7 @@
#nullable disable
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
@ -335,15 +336,85 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
if (segment.Count == 0)
continue;
HitObject.Path.ControlPoints.Add(new PathControlPoint(segment[0], PathType.BSpline(4)));
for (int j = 1; j < segment.Count - 1; j++)
HitObject.Path.ControlPoints.Add(new PathControlPoint(segment[j]));
// Replace this segment with a circular arc if it is a reasonable substitute.
var circleArcSegment = tryCircleArc(segment);
if (circleArcSegment is not null)
{
HitObject.Path.ControlPoints.Add(new PathControlPoint(circleArcSegment[0], PathType.PERFECT_CURVE));
HitObject.Path.ControlPoints.Add(new PathControlPoint(circleArcSegment[1]));
}
else
{
HitObject.Path.ControlPoints.Add(new PathControlPoint(segment[0], PathType.BSpline(4)));
for (int j = 1; j < segment.Count - 1; j++)
HitObject.Path.ControlPoints.Add(new PathControlPoint(segment[j]));
}
if (isLastSegment)
HitObject.Path.ControlPoints.Add(new PathControlPoint(segment[^1]));
}
}
private Vector2[] tryCircleArc(List<Vector2> segment)
{
if (segment.Count < 3) return null;
// Assume the segment creates a reasonable circular arc and then check if it reasonable
var points = PathApproximator.BSplineToPiecewiseLinear(segment.ToArray(), bSplineBuilder.Degree);
var circleArcControlPoints = new[] { points[0], points[points.Count / 2], points[^1] };
var circleArc = new CircularArcProperties(circleArcControlPoints);
if (!circleArc.IsValid) return null;
double length = circleArc.ThetaRange * circleArc.Radius;
if (length > 1000) return null;
double loss = 0;
Vector2? lastPoint = null;
Vector2? lastVec = null;
int? lastDir = null;
double totalWinding = 0;
// Loop through the points and check if they are not too far away from the circular arc.
// Also make sure it curves monotonically in one direction and at most one loop is done.
foreach (var point in points)
{
loss += Math.Pow((Vector2.Distance(point, circleArc.Centre) - circleArc.Radius) / length, 2);
if (lastPoint.HasValue)
{
var vec = point - lastPoint.Value;
if (lastVec.HasValue)
{
double dot = Vector2.Dot(vec, lastVec.Value);
double det = lastVec.Value.X * vec.Y - lastVec.Value.Y * vec.X;
double angle = Math.Atan2(det, dot);
int dir = Math.Sign(angle);
if (dir == 0)
continue;
if (lastDir.HasValue && dir != lastDir)
return null; // Curvature changed, like in an S-shape
totalWinding += Math.Abs(angle);
lastDir = dir;
}
lastVec = vec;
}
lastPoint = point;
}
loss /= points.Count;
return loss > 0.002 || totalWinding > MathHelper.TwoPi ? null : circleArcControlPoints;
}
private enum SliderPlacementState
{
Initial,