private static Point3D[] GetIntersection_Hull_Plane(ITriangleIndexed[] hull, ITriangle plane)
{
// Shoot through all the triangles in the hull, and get line segment intersections
List<Tuple<Point3D, Point3D>> lineSegments = null;
if (hull.Length > 100)
{
lineSegments = hull.
AsParallel().
Select(o => GetIntersection_Plane_Triangle(plane, o)).
Where(o => o != null).
ToList();
}
else
{
lineSegments = hull.
Select(o => GetIntersection_Plane_Triangle(plane, o)).
Where(o => o != null).
ToList();
}
if (lineSegments.Count < 2)
{
// length of 0 is a clear miss, 1 is just touching
//NOTE: All the points could be colinear, and just touching the hull, but deeper analysis is needed
return null;
}
// Stitch the line segments together
Point3D[] retVal = GetIntersection_Hull_PlaneSprtStitchSegments(lineSegments);
if (retVal == null)
{
// In some cases, the above method fails, so call the more generic 2D convex hull method
//NOTE: This assumes the hull is convex
retVal = GetIntersection_Hull_PlaneSprtConvexHull(lineSegments);
}
// Exit Function
return retVal; // could still be null
}
private static Point3D[] GetConnectingLines(ITriangleIndexed[] hull, Tuple<int, Point3D> intersect1, Tuple<int, Point3D> intersect2, Point3D outsideCenterPoint)
{
if (intersect1.Item1 == intersect2.Item1)
{
// They are intersecting the same triangle. Just return a line between them
return new Point3D[] { intersect1.Item2, intersect2.Item2 };
}
// Get a line from intersect1 to the edge of its triangle
var edgeIntersect1 = GetPointOnTriangleEdge(hull[intersect1.Item1], intersect1.Item2, outsideCenterPoint);
// Get a line from intersect2 to the edge of its triangle
var edgeIntersect2 = GetPointOnTriangleEdge(hull[intersect2.Item1], intersect2.Item2, outsideCenterPoint);
if (edgeIntersect1 == null && edgeIntersect2 == null)
{
// This should never happen. The only thing I can think of is intersect1 and 2 are intersecting 2 triangles, but right on their edge
return new Point3D[] { intersect1.Item2, intersect2.Item2 };
}
else if (edgeIntersect1 != null && edgeIntersect2 == null)
{
return new Point3D[] { intersect1.Item2, edgeIntersect1.Item2, intersect2.Item2 };
}
else if (edgeIntersect1 == null && edgeIntersect2 != null)
{
return new Point3D[] { intersect1.Item2, edgeIntersect2.Item2, intersect2.Item2 };
}
// edgeIntersect1 and 2 are both nonnull at this point
if (Math3D.IsNearValue(edgeIntersect1.Item2, edgeIntersect2.Item2))
{
// intersect1 and 2 are intersecting neighboring triangles, so edgeIntersect1 and 2 are the same point
return new Point3D[] { intersect1.Item2, edgeIntersect1.Item2, intersect2.Item2 };
}
// If execution gets here, there are triangles between the two intersected triangles passed in
// Convert the hull into linked triangles
TriangleIndexedLinked[] hullLinked = hull.Select(o => new TriangleIndexedLinked(o.Index0, o.Index1, o.Index2, o.AllPoints)).ToArray();
TriangleIndexedLinked.LinkTriangles_Edges(hullLinked.ToList(), true);
return GetConnectingLinesSprtBetween(hullLinked, intersect1, intersect2, edgeIntersect1, edgeIntersect2);
}
