/// <summary>
///
/// </summary>
/// <param name="p"></param>
/// <param name="p1"></param>
/// <param name="p2"></param>
public override void ComputeIntersection(ICoordinate p, ICoordinate p1, ICoordinate p2)
{
isProper = false;
// do between check first, since it is faster than the orientation test
if (Envelope.Intersects(p1, p2, p))
{
if ((CGAlgorithms.OrientationIndex(p1, p2, p) == 0) &&
(CGAlgorithms.OrientationIndex(p2, p1, p) == 0))
{
isProper = true;
if (p.Equals(p1) || p.Equals(p2))
{
isProper = false;
}
result = DoIntersect;
return;
}
}
result = DontIntersect;
}
/// <summary>
///
/// </summary>
/// <param name="p1"></param>
/// <param name="p2"></param>
/// <param name="q1"></param>
/// <param name="q2"></param>
/// <returns></returns>
public override int ComputeIntersect(ICoordinate p1, ICoordinate p2, ICoordinate q1, ICoordinate q2)
{
isProper = false;
// first try a fast test to see if the envelopes of the lines intersect
if (!Envelope.Intersects(p1, p2, q1, q2))
{
return(DontIntersect);
}
// for each endpoint, compute which side of the other segment it lies
// if both endpoints lie on the same side of the other segment,
// the segments do not intersect
int Pq1 = CGAlgorithms.OrientationIndex(p1, p2, q1);
int Pq2 = CGAlgorithms.OrientationIndex(p1, p2, q2);
if ((Pq1 > 0 && Pq2 > 0) || (Pq1 < 0 && Pq2 < 0))
{
return(DontIntersect);
}
int Qp1 = CGAlgorithms.OrientationIndex(q1, q2, p1);
int Qp2 = CGAlgorithms.OrientationIndex(q1, q2, p2);
if ((Qp1 > 0 && Qp2 > 0) || (Qp1 < 0 && Qp2 < 0))
{
return(DontIntersect);
}
bool collinear = (Pq1 == 0 && Pq2 == 0 && Qp1 == 0 && Qp2 == 0);
if (collinear)
{
return(ComputeCollinearIntersection(p1, p2, q1, q2));
}
/*
* Check if the intersection is an endpoint. If it is, copy the endpoint as
* the intersection point. Copying the point rather than computing it
* ensures the point has the exact value, which is important for
* robustness. It is sufficient to simply check for an endpoint which is on
* the other line, since at this point we know that the inputLines must
* intersect.
*/
if (Pq1 == 0 || Pq2 == 0 || Qp1 == 0 || Qp2 == 0)
{
isProper = false;
if (Pq1 == 0)
{
intPt[0] = new Coordinate(q1);
}
if (Pq2 == 0)
{
intPt[0] = new Coordinate(q2);
}
if (Qp1 == 0)
{
intPt[0] = new Coordinate(p1);
}
if (Qp2 == 0)
{
intPt[0] = new Coordinate(p2);
}
}
else
{
isProper = true;
intPt[0] = Intersection(p1, p2, q1, q2);
}
return(DoIntersect);
}