public void RayToRayCovergentNonOverlapping()
{
Ray2D ray1 = new Ray2D(new Point2D(0.0, 0.0), new Direction2D(0.0, 1.0));
Ray2D ray2 = new Ray2D(new Point2D(-1.0, -2.0), new Direction2D(1.0, 1.0));
Point2D result;
Intersector.Intersection intersection = Intersector.Intersect(ray1, ray2, out result);
Assert.AreEqual(Intersector.Intersection.DontIntersect, intersection);
}
public void RayToRayParallelIntersect()
{
Ray2D ray1 = new Ray2D(new Point2D(0.0, 0.0), new Direction2D(0.0, 1.0));
Ray2D ray2 = new Ray2D(new Point2D(1.0, 0.0), new Direction2D(0.0, 1.0));
Point2D result;
Intersector.Intersection intersection = Intersector.Intersect(ray1, ray2, out result);
Assert.AreEqual(Intersector.Intersection.DontIntersect, intersection);
}
public void SegmentToSegmentParallel()
{
Segment2D segment1 = new Segment2D(new Point2D(0.0, 0.0), new Point2D(1.0, 0.0));
Segment2D segment2 = new Segment2D(new Point2D(0.0, 1.0), new Point2D(1.0, 1.0));
Point2D result;
Intersector.Intersection intersection = Intersector.Intersect(segment1, segment2, out result);
Assert.AreEqual(Intersector.Intersection.DontIntersect, intersection);
}
public void RayToLineDiverging()
{
Ray2D ray = new Ray2D(new Point2D(0.0, 0.0), new Direction2D(-1.0, 1.0));
Line2D line = new Line2D(new Point2D(1.0, 0.0), new Point2D(1.0, 1.0));
Point2D result;
Intersector.Intersection intersection = Intersector.Intersect(ray, line, out result);
Assert.AreEqual(Intersector.Intersection.DontIntersect, intersection);
}
public void RayToRayGlancing()
{
Ray2D rayA = new Ray2D(new Point2D(4.0, 0.0), new Direction2D(-1.0, -1.0));
Ray2D rayB = new Ray2D(new Point2D(2.0, 2.0), new Direction2D(0.0, -Math.Sqrt(2.0)));
Point2D result;
Intersector.Intersection intersection = Intersector.Intersect(rayA, rayB, out result);
Assert.AreEqual(Intersector.Intersection.DoIntersect, intersection);
Assert.AreEqual(new Point2D(2.0, -2.0), result);
}
public void IntersectingBug1()
{
Segment2D[] red = { new Segment2D(new Point2D(384450, 7171260), new Point2D(384450, 7171380)) };
var one = new Segment2D(new Point2D(393160.294372512, 7169290.29437251), new Point2D(393103.309524418, 7169266.69047558));
var two = new Segment2D(new Point2D(392970, 7169820), new Point2D(392970, 7169240.58874503));
var three = new Segment2D(new Point2D(392899.705627487, 7169220), new Point2D(393967.645019878, 7169662.35498012));
Segment2D[] blue = { one, two, three };
Point2D?result = Intersector.Intersect(two, three);
var rbi = new RedBlueIntersector(red, blue);
}
public void RayToRayOrderIndependence2()
{
Ray2D rayA = new Ray2D(new Point2D(0.0, 0.0), new Direction2D(0.0, 1.0));
Ray2D rayB = new Ray2D(new Point2D(2.0, 1.0), new Direction2D(1.0, 1.0));
Point2D resultAB;
Intersector.Intersection intersectionAB = Intersector.Intersect(rayA, rayB, out resultAB);
Point2D resultBA;
Intersector.Intersection intersectionBA = Intersector.Intersect(rayB, rayA, out resultBA);
Assert.AreEqual(intersectionAB, intersectionBA);
Assert.AreEqual(resultAB, resultBA);
}
/// <summary>
/// Compute the intersections of the bisector of the supplied node with the bisectors starting
/// from the neightbour vertices in the LAV. Store the nearest intersection (if it exists) in the
/// priority queue.
/// </summary>
/// <param name="lav">The List of Active Vertices</param>
/// <param name="node">The node at the origin of the bisector to be intersected.</param>
private void EnqueueNearestBisectorIntersection(CircularLinkedList <Vertex> lav, CircularLinkedListNode <Vertex> node)
{
// TODO: Retrieve the the lav using node.List
// Find intersection with previous bisector
// TODO: For some unknown reason the ternary operator does not work for the following expression
Point2D?previousIntersection = null;
if (node.Previous != null)
{
previousIntersection = Intersector.Intersect(node.Value.Bisector, node.Previous.Value.Bisector);
}
// Find intersection with next bisector
// TODO: For some unknown reason the ternary operator does not work for the following expression
Point2D?nextIntersection = null;
if (node.Next != null)
{
nextIntersection = Intersector.Intersect(node.Value.Bisector, node.Next.Value.Bisector);
}
// Find intersection with "opposite" bisector at point B
Point2D?oppositeIntersection = null;
if (IsReflex(node.Value))
{
oppositeIntersection = OppositeIntersection(lav, node.Value);
}
double?previousDistance2 = previousIntersection.HasValue ? (previousIntersection.Value - node.Value.Bisector.Source).Magnitude2 : (double?)null;
double?nextDistance2 = nextIntersection.HasValue ? (nextIntersection.Value - node.Value.Bisector.Source).Magnitude2 : (double?)null;
double?oppDistance2 = oppositeIntersection.HasValue ? (oppositeIntersection.Value - node.Value.Bisector.Source).Magnitude2 : (double?)null;
if (IsMinimum(previousDistance2, nextDistance2, oppDistance2))
{
EnqueuePreviousIntersection(node, previousIntersection.Value);
}
else if (IsMinimum(nextDistance2, previousDistance2, oppDistance2))
{
EnqueueNextIntersection(node, nextIntersection.Value);
}
else if (IsMinimum(oppDistance2, previousDistance2, nextDistance2))
{
EnqueueOppIntersection(node, oppositeIntersection.Value);
}
}
/// <summary>
/// Determination of the co-ordinates of point B
///
/// Point B can be characterized as having the same perpendicular distance to the straight line carrying
/// the "opposite" line segment to the vertex V and from both straight lines containing the line segments
/// starting at the vertex V. We have to find such an "opposite" line segment.
///
/// We traverse all line segments e of the original polygon [polyline] and test them whether they can be
/// "opposite" line segments. Unfortunately, a simple test of the intersection between a bisector starting
/// at V and the currently tested line segment cannot be used. We have to test the intersection with the
/// line holding the edge ei and by the bisectors bi and bi+1 leading from vertices at both ends of this
/// line segment.
/// </summary>
/// <param name="lav"></param>
/// <param name="vertex"></param>
/// <returns></returns>
private static Point2D?OppositeIntersection(CircularLinkedList <Vertex> lav, Vertex vertex)
{
double minDistance2 = Double.MaxValue;
Point2D?minIncenter = null;
// Project the supporting the edges starting at V (node) as rays
Ray2D inRay = new Ray2D(vertex.inEdge.target.Position, new Direction2D(vertex.inEdge.Vector));
Ray2D outRay = new Ray2D(vertex.outEdge.source.Position, new Direction2D(-vertex.outEdge.Vector));
// Ignore cases where the in and out edges are collinear.
if (!inRay.SupportingLine.IsParallelTo(outRay.SupportingLine))
{
lav.ForEachPair(delegate(Vertex oppA, Vertex oppB)
{
// Ignore testing againt the in and out edges of V
if (oppA == vertex || oppB == vertex)
{
return;
}
// Simple intersection test between the bisector starting at V and the (whole) line containing the
// currently tested line segment ei rejects the line segments laying "behind" the vertex V. We then compute
// the co-ordinates of the candidate point Bi as the intersection between the bisector at V and the axis [bisector]
// of the angle between of the edges starting at V and the tested line segment ei. Simple check should be performed
// to exclude the case where one of the line segments starting at V us parallel to ei. The resulting point B
// is selected from all the candidates Bi as the nearest point to the vertex V
// TODO: Performance: How much code can be factored out of this loop?
// TODO: Do we need to prevent testing against the in and out edges of V?
// and the candiate "opposite" line
Line2D oppositeLine = new Line2D(oppA.outEdge.source.Position, oppA.outEdge.target.Position);
// TODO: Need to use a ray-line intersection here, where inLine and outLine are
// replaced by rays which start at V and project in alignment with the two incident edges
Point2D?inOppIntersection = Intersector.Intersect(inRay, oppositeLine);
Point2D?outOppIntersection = Intersector.Intersect(outRay, oppositeLine);
if (inOppIntersection.HasValue && outOppIntersection.HasValue)
{
Triangle2D triangle = new Triangle2D(vertex.Position, inOppIntersection.Value, outOppIntersection.Value);
if (!triangle.IsDegenerate)
{
Point2D incenter = triangle.Incenter;
// Is the incenter in the zone bounded by the oppositeLine and bisectors at the beginning
// and end of the segment embedded within it?
// TODO: Check which way round these lines are - so the the positive side defines our zone of interest
Line2D oppositeBoundary1 = oppA.Bisector.SupportingLine.Opposite;
Line2D oppositeBoundary2 = oppB.Bisector.SupportingLine;
OrientedSide sideA = oppositeBoundary1.Side(incenter);
OrientedSide sideB = oppositeLine.Side(incenter);
OrientedSide sideC = oppositeBoundary2.Side(incenter);
if (sideA == OrientedSide.Negative && sideB == OrientedSide.Negative && sideC == OrientedSide.Negative)
{
double distance2 = (incenter - vertex.Position).Magnitude2;
if (distance2 > 0.0 && distance2 < minDistance2)
{
minDistance2 = distance2;
minIncenter = incenter;
}
}
}
}
});
}
return(minIncenter);
}
