/// <summary>
/// Testing intersection between a line segment and a polyhedron and return ALL intersection points
/// </summary>
/// <param name="polyH">Polyhedron</param>
/// <param name="lineS">Line segment</param>
/// <param name="intPoints">List of intersection points</param>
/// <returns></returns>
public static bool intersect(Polyhedron polyH, LineSegment3D lineS, out List <Point3D> intPoints)
{
List <Point3D> iPoints = new List <Point3D>();
intPoints = iPoints;
List <Point3D> corners = new List <Point3D>();
corners.Add(lineS.startPoint);
corners.Add(lineS.endPoint);
BoundingBox3D bound = new BoundingBox3D(corners);
List <Face3D> reducedList = Face3D.exclFacesOutsideOfBound(polyH.Faces, bound, 0x111);
if (reducedList.Count == 0)
{
return(false); // no faces left, either they are all on the left or they are all on the right
}
// Now test whether there is any intersection. It needs to complete the test with entire faces to collect the intersection points
for (int i = 0; i < reducedList.Count; i++)
{
List <Point3D> iPts = new List <Point3D>();
if (Face3D.intersect(reducedList[i], lineS, out iPts))
{
for (int j = 0; j < iPts.Count; j++)
{
iPoints.Add(iPts[j]);
}
}
}
if (iPoints.Count > 0)
{
return(true);
}
return(false);
}
/// <summary>
/// Testing a point inside a polyhedron is similar with the 2D version of a point inside a polygon by testing intersection between a ray starting from the point.
/// If the number of intersection is odd the point is inside. In 3D the intersection is against the Faces
/// </summary>
/// <param name="polyH"></param>
/// <param name="aPoint"></param>
/// <returns></returns>
public static bool inside(Polyhedron polyH, Point3D aPoint)
{
double extent = 0;
if (Octree.WorldBB == null)
{
extent = Point3D.distance(polyH.boundingBox.LLB, polyH.boundingBox.URT);
}
else
{
extent = Octree.WorldBB.extent;
}
// define a ray using linesegment from the point toward and along +X-axis with 2*the extent of the World BB to ensure ray is always long enough
LineSegment3D ray = new LineSegment3D(aPoint, new Point3D(aPoint.X + 2 * extent, aPoint.Y, aPoint.Z));
List <Face3D> reducedList = Face3D.inclFacesBeyondAxis(polyH.Faces, new Plane3D(aPoint, new Vector3D(1.0, 0.0, 0.0))); // beyond YZ plane
List <Point3D> corners = new List <Point3D>();
corners.Add(aPoint);
corners.Add(aPoint);
BoundingBox3D bound = new BoundingBox3D(corners);
if (reducedList.Count > 0)
{
reducedList = Face3D.exclFacesOutsideOfBound(reducedList, bound, 0x011); // reduce list on Y and Z both direction
}
if (reducedList.Count == 0)
{
return(false); // no faces left, either they are all on the left or they are all on the right
}
int iCount = 0;
for (int i = 0; i < reducedList.Count; i++)
{
List <Point3D> intPts = new List <Point3D>();
if (Face3D.intersect(reducedList[i], ray, out intPts))
{
iCount++;
}
}
if ((iCount % 2) == 1)
{
return(true);
}
return(false);
}
/// <summary>
/// To determine that a line segment is inside (completely inside) of a polyhedron, it must satisfy the following:
/// 1. both end points are inside the polyhedron
/// 2. There no intersection between the segment and the polyhedron
/// </summary>
/// <param name="polyH"></param>
/// <param name="lineS"></param>
/// <returns></returns>
public static bool inside(Polyhedron polyH, LineSegment3D lineS)
{
// reducing the face candidate list is less expensive than inside test, do it first
Point3D leftX = new Point3D();
Point3D rightX = new Point3D();
leftX.X = lineS.startPoint.X < lineS.endPoint.X ? lineS.startPoint.X : lineS.endPoint.X;
rightX.X = lineS.startPoint.X < lineS.endPoint.X ? lineS.endPoint.X : lineS.startPoint.X;
List <Face3D> reducedList = Face3D.inclFacesBeyondAxis(polyH.Faces, new Plane3D(leftX, new Vector3D(1.0, 0.0, 0.0)));
// reducedList = Face3D.exclFacesBeyondAxis(reducedList, rightX); // cannot remove this otherwise inside test for StartPoint may not be correct!!!
List <Point3D> corners = new List <Point3D>();
corners.Add(lineS.startPoint);
corners.Add(lineS.endPoint);
BoundingBox3D bound = new BoundingBox3D(corners);
if (reducedList.Count > 0)
{
reducedList = Face3D.exclFacesOutsideOfBound(reducedList, bound, 0x011); // reduce list on Y and Z both direction
}
if (reducedList.Count == 0)
{
return(false); // no faces left, either they are all on the left or they are all on the right
}
// inside test for both segment ends. Test one by one so that we can exit when any one of them are not inside
if (!inside(polyH, lineS.startPoint))
{
return(false);
}
if (!inside(polyH, lineS.endPoint))
{
return(false);
}
// Now test whether there is any intersection. If there is, the segment is not completely inside
for (int i = 0; i < reducedList.Count; i++)
{
List <Point3D> iPoints = new List <Point3D>();
if (Face3D.intersect(reducedList[i], lineS, out iPoints))
{
return(false);
}
}
return(true);
}
/// <summary>
/// Test intersection between a polyhedron and a face. There is optmization applied for axis-aligned face (useful for Octree cells as they are all axis aligned)
/// </summary>
/// <param name="polyH">The Polyhedron</param>
/// <param name="face">The face to test the intersection</param>
/// <returns>true=intersected; false otherwise</returns>
public static bool intersect(Polyhedron polyH, Face3D face)
{
List <Face3D> faceList = new List <Face3D>();
BoundingBox3D bound = new BoundingBox3D(face.vertices);
faceList = Face3D.exclFacesOutsideOfBound(polyH.Faces, bound, 0x111);
if (faceList.Count == 0)
{
return(false); // There is no face remaining to test, return false
}
for (int i = 0; i < faceList.Count; i++)
{
FaceIntersectEnum mode;
LineSegment3D intL = new LineSegment3D(new Point3D(), new Point3D());
bool status = Face3D.intersect(face, faceList[i], out intL, out mode);
if (status == true)
{
return(true); // return true as soon as an intersection is detected
}
}
return(false);
}
/// <summary>
/// Testing intersection between a line segment and a polyhedron only. It stops at the first intersection
/// </summary>
/// <param name="polyH">polyhedron</param>
/// <param name="lineS">Line segment</param>
/// <returns></returns>
public static bool intersect(Polyhedron polyH, LineSegment3D lineS)
{
List <Point3D> corners = new List <Point3D>();
corners.Add(lineS.startPoint);
corners.Add(lineS.endPoint);
BoundingBox3D bound = new BoundingBox3D(corners);
List <Face3D> reducedList = Face3D.exclFacesOutsideOfBound(polyH.Faces, bound, 0x111);
if (reducedList.Count == 0)
{
return(false); // no faces left, either they are all on the left or they are all on the right
}
// Now test whether there is any intersection.
for (int i = 0; i < reducedList.Count; i++)
{
List <Point3D> iPoints = new List <Point3D>();
if (Face3D.intersect(reducedList[i], lineS, out iPoints))
{
return(true);
}
}
return(false);
}
public static void Process(OctreeNode node, Polyhedron _polyH, List <Face3D> polyHF)
{
// 3rd step. Subdivide the cells collected by the step 2 and operate on them with the actual polyhedron to get the detail
if (node._depth < Octree.MaxDepth)
{
int disjointCount = 0;
int insideCount = 0;
Split(node);
List <int> childToRemove = new List <int>();
List <int> childToTraverse = new List <int>();
List <Face3D> faceList;
faceList = Face3D.exclFacesOutsideOfBound(polyHF, node.nodeCellCuboid.cuboidPolyhedron.boundingBox, 0x111);
if (faceList.Count == 0)
{
// No face inside this cuboid left, no intersection nor completely enclosing the polyH.
node._flag = PolyhedronIntersectEnum.Disjoint;
node._children.Clear();
return;
}
for (int i = 0; i < node._children.Count; i++)
{
OctreeNode childNode = node._children[i];
//PolyhedronIntersectEnum intS = childNode.Process(polyH);
if (Polyhedron.intersect(childNode.nodeCellCuboid.cuboidPolyhedron, faceList))
{
childToTraverse.Add(i);
childNode._flag = PolyhedronIntersectEnum.Intersect;
childNode.nodeCellID.setBorderCell();
#if (DBG_OCTREE)
if (childNode._depth >= _dbgDepth)
{
BIMRLCommon refCommon = new BIMRLCommon();
string dbgFile = "c:\\temp\\octree\\" + childNode.nodeCellID.ToString() + " - intersect polyH.x3d";
BIMRLExportSDOToX3D x3d = new BIMRLExportSDOToX3D(refCommon, dbgFile);
x3d.drawCellInX3d(childNode.nodeCellID.ToString()); // draw the cell
x3d.exportFacesToX3D(faceList);
x3d.endExportToX3D();
}
#endif
continue;
}
// If doesn't intersect (passes the check above), either it is fully contained, full contains or disjoint
// To optimize the operation, we will use a single sampling point instead of checking the entire polyhedron since a single point can tell if a polyhedron is inside the other one
//if (Polyhedron.inside(childNode.nodeCellCuboid.cuboidPolyhedron, polyH))
//// No need to check this since the previous step (no 1) would have removed the fullycontaining cells
// Fully contains check only valid if the parent is fully contains, if intersect, it should never be full contains
//if (node._flag == PolyhedronIntersectEnum.FullyContains)
//{
// if (Polyhedron.insideCuboid(childNode.nodeCellCuboid.cuboidPolyhedron, faceList[0].vertices[0]))
// {
// // if polyH is entirely inside the cuboid, we will set this for further split (the same as intersection
// childToTraverse.Add(i); // We will remove the node if it is disjoint, otherwise it will continue splitting until the condition met
// childNode._flag = PolyhedronIntersectEnum.FullyContains;
// childNode.nodeCellID.setBorderCell();
// continue;
// }
//}
//if (Polyhedron.inside(polyH, childNode.nodeCellCuboid.cuboidPolyhedron))
if (Polyhedron.inside(_polyH, childNode.nodeCellCuboid.cuboidPolyhedron.Vertices[3]))
{
childNode._flag = PolyhedronIntersectEnum.Inside;
insideCount++;
#if (DBG_OCTREE)
if (childNode._depth >= _dbgDepth)
{
BIMRLCommon refCommon = new BIMRLCommon();
string dbgFile = "c:\\temp\\octree\\" + childNode.nodeCellID.ToString() + " - inside polyH.x3d";
BIMRLExportSDOToX3D x3d = new BIMRLExportSDOToX3D(refCommon, dbgFile);
x3d.drawCellInX3d(childNode.nodeCellID.ToString()); // draw the cell
x3d.exportFacesToX3D(_polyH.Faces);
x3d.endExportToX3D();
}
#endif
continue;
}
// If the 2 polyH do not intersect, the cuboid does not fully contain the polyH, nor the cuboid is fully inside the polyH, it must be disjoint
childNode._flag = PolyhedronIntersectEnum.Disjoint;
disjointCount++;
#if (DBG_OCTREE)
if (childNode._depth >= _dbgDepth)
{
BIMRLCommon refCommon = new BIMRLCommon();
string dbgFile = "c:\\temp\\octree\\" + childNode.nodeCellID.ToString() + " - disjoint polyH.x3d";
BIMRLExportSDOToX3D x3d = new BIMRLExportSDOToX3D(refCommon, dbgFile);
x3d.drawCellInX3d(childNode.nodeCellID.ToString()); // draw the cell
x3d.exportFacesToX3D(_polyH.Faces);
x3d.endExportToX3D();
}
#endif
continue;
// else: the cuboid is completely inside the polyH, keep
}
if (disjointCount == 8)
{
// All children are disjoint. Remove all children and set the node to Disjoint
node._children.Clear();
node._flag = PolyhedronIntersectEnum.Disjoint;
return;
}
if (insideCount == 8)
{
// All children are inside. Remove all children and set the node to Inside
node._children.Clear();
node._flag = PolyhedronIntersectEnum.Inside;
return;
}
if (childToTraverse.Count == 1)
{
OctreeNodeProcess.Process(node._children[childToTraverse[0]], _polyH, faceList);
}
else if (childToTraverse.Count > 1)
{
#if (DEBUG_NOPARALLEL)
// Non - parallel option for easier debugging
foreach (int i in childToTraverse)
{
OctreeNodeProcess.Process(node._children[i], _polyH, faceList);
}
#else
ParallelOptions po = new ParallelOptions();
po.MaxDegreeOfParallelism = 8;
Parallel.ForEach(childToTraverse, po, i => OctreeNodeProcess.Process(node._children[i], _polyH, faceList));
#endif
}
// If there is any disjoint, we need to keep this node as it is. This should be done after we processed all the children to be traversed!!
if (disjointCount > 0 && disjointCount < 8)
{
return;
}
int countGrandChildren = 0;
// If there is no disjoint, we need to check whether all children are terminal (i.e. child._children.Count == 0)
foreach (OctreeNode child in node._children)
{
countGrandChildren += child._children.Count;
}
// All children are terminal and no disjoint (by implication of previous steps). Remove children
if (countGrandChildren == 0)
{
node._children.Clear();
node._flag = PolyhedronIntersectEnum.IntersectOrInside;
return;
}
}
else
{
// at _depth == Octree.MaxDepth there is nothing else to do since the test has been done at the parent level and when entering this stage, the test has determined
// that the cell is intersected with the polyH
}
return;
}
