public bool PerpendicularTo(Point3d P0, Point3d P1, Point3d P2)
{
Vector3d V0, V1, V2, N0, N1, N2;
V0 = P2 - P1;
V1 = P0 - P2;
V2 = P1 - P0;
N0 = Vector3d.CrossProduct(V1, V2);
if (!N0.Unitize())
{
return(false);
}
N1 = Vector3d.CrossProduct(V2, V0);
if (!N1.Unitize())
{
return(false);
}
N2 = Vector3d.CrossProduct(V0, V1);
if (!N2.Unitize())
{
return(false);
}
double s0 = 1.0 / V0.Length;
double s1 = 1.0 / V1.Length;
double s2 = 1.0 / V2.Length;
double e0 = s0 * Math.Abs(Vector3d.DotProduct(N0, V0)) + s1 * Math.Abs(Vector3d.DotProduct(N0, V1)) + s2 * Math.Abs(Vector3d.DotProduct(N0, V2));
double e1 = s0 * Math.Abs(Vector3d.DotProduct(N1, V0)) + s1 * Math.Abs(Vector3d.DotProduct(N1, V1)) + s2 * Math.Abs(Vector3d.DotProduct(N1, V2));
double e2 = s0 * Math.Abs(Vector3d.DotProduct(N2, V0)) + s1 * Math.Abs(Vector3d.DotProduct(N2, V1)) + s2 * Math.Abs(Vector3d.DotProduct(N2, V2));
if (e0 <= e1)
{
if (e0 <= e2)
{
this = N0;
}
else
{
this = N2;
}
}
else if (e1 <= e2)
{
this = N1;
}
else
{
this = N2;
}
return(true);
}