public void TestIntersectsWithLine()
{
// polygons to intersect with
Polygon3D t = new Polygon3D(new List <Point3D> {
t1_1, t1_2, t1_3
}, "t");
Polygon3D s = new Polygon3D(new List <Point3D> {
s1_1, s1_2, s1_3, s1_4
}, "s");
// --
// line in the same plane as polygons
// --
// line going through polygons in the same plane
Point3D start = new Point3D(1, 4, 0);
Point3D end = new Point3D(1, -3, 0);
Assert.AreEqual(t.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(s.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(t.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(t.IntersectsWith(start, end, 0, false), false);
Assert.AreEqual(s.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(s.IntersectsWith(start, end, 0, false), false);
// line not going through the polygons in the same plane
start = new Point3D(4, 4, 0);
end = new Point3D(4, -3, 0);
Assert.AreEqual(t.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(s.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(t.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(t.IntersectsWith(start, end, 0, false), false);
Assert.AreEqual(s.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(s.IntersectsWith(start, end, 0, false), false);
// line starting in polygon going out in the same plane
start = new Point3D(2, 2, 0);
end = new Point3D(2, -0.5, 0);
Assert.AreEqual(t.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(s.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(t.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(t.IntersectsWith(start, end, 0, false), false);
Assert.AreEqual(s.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(s.IntersectsWith(start, end, 0, false), false);
// line inside square in the same plane
start = new Point3D(0.5, 0.5, 0);
end = new Point3D(2, 0.5, 0);
Assert.AreEqual(s.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(s.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(s.IntersectsWith(start, end, 0, false), false);
// line inside triangle in the same plane
start = new Point3D(2, 2, 0);
end = new Point3D(2, -0.5, 0);
Assert.AreEqual(t.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(t.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(t.IntersectsWith(start, end, 0, false), false);
// line = border of square in the same plane
start = s1_1;
end = s1_2;
Assert.AreEqual(s.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(s.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(s.IntersectsWith(start, end, 0, false), false);
// line = border of triangle in the same plane
start = t1_1;
end = t1_2;
Assert.AreEqual(t.IntersectionWith(start, end).IsNaN(), true);
Assert.AreEqual(t.IntersectsWith(start, end, 0, true), false);
Assert.AreEqual(t.IntersectsWith(start, end, 0, false), false);
// --
// now lines which are not in plane of the polygons in fact all lines in z-axis direction
// --
// three cases of line intersecting square at s1_4 (0, 3, 0)
start = new Point3D(0, 3, -2);
end = new Point3D(0, 3, 2);
Assert.AreEqual(s.IntersectionWith(start, end), s1_4);
Assert.IsTrue(s.IntersectsWith(start, end, 0, true));
Assert.IsTrue(s.IntersectsWith(start, end, 0, false));
start = new Point3D(0, 3, -2);
end = new Point3D(0, 3, 0);
Assert.AreEqual(s.IntersectionWith(start, end), s1_4);
Assert.IsTrue(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
start = new Point3D(0, 3, -2);
end = new Point3D(0, 3, -1);
Assert.IsTrue(s.IntersectionWith(start, end).IsNaN());
Assert.IsFalse(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
// three cases of line intersecting square at (1, 4, 0) - no intersection
start = new Point3D(1, 4, -2);
end = new Point3D(1, 4, 2);
Assert.IsTrue(s.IntersectionWith(start, end).IsNaN());
Assert.IsFalse(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
start = new Point3D(1, 4, -2);
end = new Point3D(1, 4, 0);
Assert.IsTrue(s.IntersectionWith(start, end).IsNaN());
Assert.IsFalse(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
start = new Point3D(1, 4, -2);
end = new Point3D(1, 4, -1);
Assert.IsTrue(s.IntersectionWith(start, end).IsNaN());
Assert.IsFalse(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
// three cases of line intersecting square on the edge (1, 3, 0)
Point3D isec = new Point3D(1, 3, 0);
start = new Point3D(1, 3, -2);
end = new Point3D(1, 3, 2);
Assert.AreEqual(s.IntersectionWith(start, end), isec);
Assert.IsTrue(s.IntersectsWith(start, end, 0, true));
Assert.IsTrue(s.IntersectsWith(start, end, 0, false));
start = new Point3D(1, 3, -2);
end = new Point3D(1, 3, 0);
Assert.AreEqual(s.IntersectionWith(start, end), isec);
Assert.IsTrue(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
start = new Point3D(1, 3, -2);
end = new Point3D(1, 3, -1);
Assert.IsTrue(s.IntersectionWith(start, end).IsNaN());
Assert.IsFalse(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
// three cases of line intersecting square insede (2, 2, 0)
isec = new Point3D(2, 2, 0);
start = new Point3D(2, 2, -2);
end = new Point3D(2, 2, 2);
Assert.AreEqual(s.IntersectionWith(start, end), isec);
Assert.IsTrue(s.IntersectsWith(start, end, 0, true));
Assert.IsTrue(s.IntersectsWith(start, end, 0, false));
start = new Point3D(2, 2, -2);
end = new Point3D(2, 2, 0);
Assert.AreEqual(s.IntersectionWith(start, end), isec);
Assert.IsTrue(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
start = new Point3D(2, 2, -2);
end = new Point3D(2, 2, -1);
Assert.IsTrue(s.IntersectionWith(start, end).IsNaN());
Assert.IsFalse(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
// triangle not tested, assuming it will behave the same way
// --
// now lines paralel to the plane of the polygon
// --
start = new Point3D(1, 4, 1);
end = new Point3D(1, -3, 1);
Assert.IsTrue(s.IntersectionWith(start, end).IsNaN());
Assert.IsFalse(s.IntersectsWith(start, end, 0, true));
Assert.IsFalse(s.IntersectsWith(start, end, 0, false));
}