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clean up code

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This commit is contained in:
OliBomby 2024-09-14 17:26:04 +02:00
parent f7503ee2c8
commit 30096c1c71
1 changed files with 27 additions and 47 deletions
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74
osu.Game/Utils/GeometryUtils.cs
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@ -152,72 +152,52 @@ namespace osu.Game.Utils
/// <param name="points">The points to calculate a convex hull.</param> /// <param name="points">The points to calculate a convex hull.</param>
public static List<Vector2> GetConvexHull(IEnumerable<Vector2> points) public static List<Vector2> GetConvexHull(IEnumerable<Vector2> points)
{ {
// Naming convention implies positive y upwards. var pointsList = points.OrderBy(p => p.X).ThenBy(p => p.Y).ToList();
bool isCCW(Vector2 a, Vector2 b, Vector2 c) => crossProduct(b - a, c - a) > 0;
float crossProduct(Vector2 v1, Vector2 v2) => v1.X * v2.Y - v1.Y * v2.X;
var pointsList = points.ToList();
pointsList.Sort(delegate (Vector2 point1, Vector2 point2)
{
if (point1.X == point2.X)
return point1.Y.CompareTo(point2.Y);
return point1.X.CompareTo(point2.X);
});
if (pointsList.Count < 3) if (pointsList.Count < 3)
return pointsList; return pointsList;
var convexHullUpper = new List<Vector2> var convexHullLower = new List<Vector2>
{ {
pointsList[0], pointsList[0],
pointsList[1] pointsList[1]
}; };
var convexHullLower = new List<Vector2> var convexHullUpper = new List<Vector2>
{ {
pointsList[pointsList.Count - 1], pointsList[^1],
pointsList[pointsList.Count - 2] pointsList[^2]
}; };
for (int i_points = 2; i_points < pointsList.Count; i_points++) // Build the lower hull.
for (int i = 2; i < pointsList.Count; i++)
{ {
Vector2 c = pointsList[i_points]; Vector2 c = pointsList[i];
for (int i_hull = convexHullUpper.Count - 1; i_hull > 0; i_hull--) while (convexHullLower.Count > 1 && isClockwise(convexHullLower[^2], convexHullLower[^1], c))
{ convexHullLower.RemoveAt(convexHullLower.Count - 1);
Vector2 a = convexHullUpper[^2];
Vector2 b = convexHullUpper[^1];
if (isCCW(a, b, c))
convexHullUpper.Remove(b);
else
break;
}
convexHullUpper.Add(c);
}
for (int i_points = pointsList.Count - 3; i_points >= 0; i_points--)
{
Vector2 c = pointsList[i_points];
for (int i_hull = convexHullLower.Count - 1; i_hull > 0; i_hull--)
{
Vector2 a = convexHullLower[^2];
Vector2 b = convexHullLower[^1];
if (isCCW(a, b, c))
convexHullLower.Remove(b);
else
break;
}
convexHullLower.Add(c); convexHullLower.Add(c);
} }
convexHullUpper.RemoveAt(convexHullUpper.Count - 1); // Build the upper hull.
for (int i = pointsList.Count - 3; i >= 0; i--)
{
Vector2 c = pointsList[i];
while (convexHullUpper.Count > 1 && isClockwise(convexHullUpper[^2], convexHullUpper[^1], c))
convexHullUpper.RemoveAt(convexHullUpper.Count - 1);
convexHullUpper.Add(c);
}
convexHullLower.RemoveAt(convexHullLower.Count - 1); convexHullLower.RemoveAt(convexHullLower.Count - 1);
convexHullUpper.RemoveAt(convexHullUpper.Count - 1);
convexHullUpper.AddRange(convexHullLower); convexHullLower.AddRange(convexHullUpper);
var convexHull = convexHullUpper;
return convexHull; return convexHullLower;
float crossProduct(Vector2 v1, Vector2 v2) => v1.X * v2.Y - v1.Y * v2.X;
bool isClockwise(Vector2 a, Vector2 b, Vector2 c) => crossProduct(b - a, c - a) >= 0;
} }
public static List<Vector2> GetConvexHull(IEnumerable<IHasPosition> hitObjects) => public static List<Vector2> GetConvexHull(IEnumerable<IHasPosition> hitObjects) =>