public Vector CrossingPoint(Segment other)
{
float x = -((begin.X * end.Y - end.X * begin.Y) * (other.End.X - other.Begin.X) - (other.Begin.X * other.End.Y - other.End.X * other.Begin.Y) * (end.X - begin.X)) / ((begin.Y - end.Y) * (other.End.X - other.Begin.X) - (other.Begin.Y - other.End.Y) * (end.X - begin.X));
if (x == float.NaN)
return null;
float y = ((other.Begin.Y - other.End.Y) * (-x) - (other.Begin.X * other.End.Y - other.End.X * other.Begin.Y)) / (other.End.X - other.Begin.X);
return new Vector(x, y);
}
public static MyPolygon Intersection(MyPolygon a, Segment b)
{
List<Vector> result = new List<Vector>();
a.points.Add(a.points.First());
for (int i = 0; i < a.points.Count - 1; i++)
{
Vector start = a.points[i];
Vector end = a.points[i + 1];
bool s = b.PlaceOfPoint(start) <= 0; //справа
bool e = b.PlaceOfPoint(end) <= 0;
if (s)
result.Add(start);
if (s ^ e)
result.Add(b.CrossingPoint(new Segment(start, end)));
}
return new MyPolygon(result);
}