public bool Intersection(Segment2d segment, out Vector2d intersection, out Segment2d seg)
{
var x1 = A.X;
var y1 = A.Y;
var x2 = B.X;
var y2 = B.Y;
var x3 = segment.A.X;
var y3 = segment.A.Y;
var x4 = segment.B.X;
var y4 = segment.B.Y;
var denom = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
if (Math.Abs(denom) > float.Epsilon)
{
var t = ((x1 - x3) * (y3 - y4) - (y1 - y3) * (x3 - x4)) / denom;
var u = ((x1 - x2) * (y1 - y3) - (y1 - y2) * (x1 - x3)) / -denom;
if (Vec.InOpenRange(t, 0, 1) && Vec.InOpenRange(u, 0, 1))
{
intersection = new Vector2d(
x1 + t * (x2 - x1),
y1 + t * (y2 - y1)
);
seg = NaN;
return(true);
}
}
else
{
var onSegment = new SortedSet <Vector2d>(new OriginComparer());
var o1 = Vec.CheckOrientation(segment.A, A, B);
var o2 = Vec.CheckOrientation(segment.B, A, B);
var o3 = Vec.CheckOrientation(A, segment.A, segment.B);
var o4 = Vec.CheckOrientation(B, segment.A, segment.B);
//shit code
if (o1 == Orientation.ON_SEGMENT)
{
onSegment.Add(segment.A);
}
if (o2 == Orientation.ON_SEGMENT)
{
onSegment.Add(segment.B);
}
if (o3 == Orientation.ON_SEGMENT)
{
onSegment.Add(A);
}
if (o4 == Orientation.ON_SEGMENT)
{
onSegment.Add(B);
}
var or = new[] { o1, o2, o3, o4 };
if (o1 == o2 && o2 == o3 & o3 == o4 && o4 == Orientation.ONLINE)
{
intersection = Vector2d.NaN;
seg = NaN;
return(false);
}
if (o1 == o2 && o2 == o3 & o3 == o4 && o4 == Orientation.ON_SEGMENT)
{
intersection = Vector2d.NaN;
seg = segment;
return(true);
}
if (or.Any(n => n == Orientation.LEFT || n == Orientation.RIGHT))
{
intersection = Vector2d.NaN;
seg = NaN;
return(false);
}
if (onSegment.Count == 1)
{
intersection = onSegment.First();
seg = NaN;
return(true);
}
if (onSegment.Count > 1)
{
var arr = onSegment.ToArray();
double minDist = double.MaxValue; // don't need
var a = Vector2d.NaN;
var b = Vector2d.NaN;
for (int i = 0; i < arr.Length - 1; i++)
{
var cur = (i + 1) % onSegment.Count;
var next = (cur + 1) % onSegment.Count;
//govno code
var sqrDist = arr[cur].SqrDist(arr[next]);
if (sqrDist < minDist)
{
minDist = sqrDist;
a = arr[cur];
b = arr[next];
}
}
intersection = Vector2d.NaN;
seg = new Segment2d(a, b);
return(true);
}
}
intersection = Vector2d.NaN;
seg = NaN;
return(false);
}
