/// <summary>
/// Finds the adjacencies between triangles and subsegments.
/// </summary>
private static void SetSegments(TriangleNetMesh triangleNetMesh, Polygon polygon, List <Otri>[] vertexarray)
{
Otri checktri = default(Otri);
Otri nexttri; // Triangle
TVertex checkdest;
Otri checkneighbor = default(Otri);
Osub subseg = default(Osub);
Otri prevlink; // Triangle
TVertex tmp;
TVertex sorg, sdest;
bool notfound;
//bool segmentmarkers = false;
int boundmarker;
int aroundvertex;
int i;
int hullsize = 0;
// Prepare to count the boundary edges.
if (triangleNetMesh.behavior.Poly)
{
// Link the segments to their neighboring triangles.
boundmarker = 0;
i = 0;
foreach (var item in triangleNetMesh.subsegs.Values)
{
subseg.seg = item;
sorg = polygon.Segments[i].GetVertex(0);
sdest = polygon.Segments[i].GetVertex(1);
boundmarker = polygon.Segments[i].Label;
if ((sorg.id < 0 || sorg.id >= triangleNetMesh.invertices) || (sdest.id < 0 || sdest.id >= triangleNetMesh.invertices))
{
Log.Instance.Error("Segment has an invalid vertex index.", "MeshReader.Reconstruct()");
throw new Exception("Segment has an invalid vertex index.");
}
// set the subsegment's vertices.
subseg.orient = 0;
subseg.SetOrg(sorg);
subseg.SetDest(sdest);
subseg.SetSegOrg(sorg);
subseg.SetSegDest(sdest);
subseg.seg.boundary = boundmarker;
// Try linking the subsegment to triangles that share these vertices.
for (subseg.orient = 0; subseg.orient < 2; subseg.orient++)
{
// Take the number for the destination of subsegloop.
aroundvertex = subseg.orient == 1 ? sorg.id : sdest.id;
int index = vertexarray[aroundvertex].Count - 1;
// Look for triangles having this vertex.
prevlink = vertexarray[aroundvertex][index];
nexttri = vertexarray[aroundvertex][index];
checktri = nexttri;
tmp = subseg.Org();
notfound = true;
// Look for triangles having this edge. Note that I'm only
// comparing each triangle's destination with the subsegment;
// each triangle's apex is handled through a different vertex.
// Because each triangle appears on three vertices' lists, each
// occurrence of a triangle on a list can (and does) represent
// an edge. In this way, most edges are represented twice, and
// every triangle-subsegment bond is represented once.
while (notfound && (checktri.tri.id != TriangleNetMesh.DUMMY))
{
checkdest = checktri.Dest();
if (tmp == checkdest)
{
// We have a match. Remove this triangle from the list.
//prevlink = vertexarray[aroundvertex][index];
vertexarray[aroundvertex].Remove(prevlink);
// Bond the subsegment to the triangle.
checktri.SegBond(ref subseg);
// Check if this is a boundary edge.
checktri.Sym(ref checkneighbor);
if (checkneighbor.tri.id == TriangleNetMesh.DUMMY)
{
// The next line doesn't insert a subsegment (because there's
// already one there), but it sets the boundary markers of
// the existing subsegment and its vertices.
triangleNetMesh.InsertSubseg(ref checktri, 1);
hullsize++;
}
notfound = false;
}
index--;
// Find the next triangle in the stack.
prevlink = vertexarray[aroundvertex][index];
nexttri = vertexarray[aroundvertex][index];
checktri = nexttri;
}
}
i++;
}
}
// Mark the remaining edges as not being attached to any subsegment.
// Also, count the (yet uncounted) boundary edges.
for (i = 0; i < triangleNetMesh.vertices.Count; i++)
{
// Search the stack of triangles adjacent to a vertex.
int index = vertexarray[i].Count - 1;
nexttri = vertexarray[i][index];
checktri = nexttri;
while (checktri.tri.id != TriangleNetMesh.DUMMY)
{
// Find the next triangle in the stack before this
// information gets overwritten.
index--;
nexttri = vertexarray[i][index];
// No adjacent subsegment. (This overwrites the stack info.)
checktri.SegDissolve(triangleNetMesh.dummysub);
checktri.Sym(ref checkneighbor);
if (checkneighbor.tri.id == TriangleNetMesh.DUMMY)
{
triangleNetMesh.InsertSubseg(ref checktri, 1);
hullsize++;
}
checktri = nexttri;
}
}
triangleNetMesh.hullsize = hullsize;
}
