/// <summary>
/// Form a Delaunay triangulation by incrementally inserting vertices.
/// </summary>
/// <returns>
/// Returns the number of edges on the convex hull of the
/// triangulation.
/// </returns>
public Mesh Triangulate(List <Vertex> points)
{
mesh = TrianglePool.AllocMesh();
mesh.TransferNodes(points);
Otri starttri = new Otri();
// Create a triangular bounding box.
GetBoundingBox();
foreach (var v in mesh.vertices.Values)
{
starttri.tri = mesh.dummytri;
Osub tmp = default(Osub);
if (mesh.InsertVertex(v, ref starttri, ref tmp, false, false) == InsertVertexResult.Duplicate)
{
v.type = VertexType.UndeadVertex;
mesh.undeads++;
}
}
// Remove the bounding box.
mesh.hullsize = RemoveBox();
return(mesh);
}
/// <summary>
/// Form a Delaunay triangulation by the divide-and-conquer method.
/// </summary>
/// <returns></returns>
/// <remarks>
/// Sorts the vertices, calls a recursive procedure to triangulate them, and
/// removes the bounding box, setting boundary markers as appropriate.
/// </remarks>
public Mesh Triangulate(List <Vertex> points)
{
this.mesh = TrianglePool.AllocMesh();
this.mesh.TransferNodes(points);
Otri hullleft = default(Otri), hullright = default(Otri);
int divider;
int i, j, n = points.Count;
sortarray = points;
VertexSort(0, n - 1);
// Discard duplicate vertices, which can really mess up the algorithm.
i = 0;
for (j = 1; j < n; j++)
{
if ((sortarray[i].X == sortarray[j].X) && (sortarray[i].Y == sortarray[j].Y))
{
sortarray[j].type = VertexType.UndeadVertex;
mesh.undeads++;
}
else
{
i++;
sortarray[i] = sortarray[j];
}
}
i++;
if (UseDwyer)
{
// Re-sort the array of vertices to accommodate alternating cuts.
divider = i >> 1;
if (i - divider >= 2)
{
if (divider >= 2)
{
AlternateAxes(0, divider - 1, 1);
}
AlternateAxes(divider, i - 1, 1);
}
}
// Form the Delaunay triangulation.
DivconqRecurse(0, i - 1, 0, ref hullleft, ref hullright);
//DebugWriter.Session.Write(mesh);
//DebugWriter.Session.Finish();
this.mesh.hullsize = RemoveGhosts(ref hullleft);
return(this.mesh);
}
public Mesh Triangulate(List <Vertex> points)
{
mesh = TrianglePool.AllocMesh();
mesh.TransferNodes(points);
// Nonexistent x value used as a flag to mark circle events in sweepline
// Delaunay algorithm.
xminextreme = 10 * mesh.bounds.Left - 9 * mesh.bounds.Right;
SweepEvent[] eventheap;
SweepEvent nextevent;
SweepEvent newevent;
SplayNode splayroot;
Otri bottommost = default(Otri);
Otri searchtri = default(Otri);
Otri fliptri;
Otri lefttri = default(Otri);
Otri righttri = default(Otri);
Otri farlefttri = default(Otri);
Otri farrighttri = default(Otri);
Otri inserttri = default(Otri);
Vertex firstvertex, secondvertex;
Vertex nextvertex, lastvertex;
Vertex connectvertex;
Vertex leftvertex, midvertex, rightvertex;
double lefttest, righttest;
int heapsize;
bool check4events, farrightflag = false;
splaynodes = new List <SplayNode>();
splayroot = null;
CreateHeap(out eventheap); //, out events, out freeevents);
heapsize = mesh.invertices;
mesh.MakeTriangle(ref lefttri);
mesh.MakeTriangle(ref righttri);
lefttri.Bond(ref righttri);
lefttri.Lnext();
righttri.Lprev();
lefttri.Bond(ref righttri);
lefttri.Lnext();
righttri.Lprev();
lefttri.Bond(ref righttri);
firstvertex = eventheap[0].vertexEvent;
HeapDelete(eventheap, heapsize, 0);
heapsize--;
do
{
if (heapsize == 0)
{
throw new Exception("Input vertices are all identical.");
}
secondvertex = eventheap[0].vertexEvent;
HeapDelete(eventheap, heapsize, 0);
heapsize--;
if ((firstvertex.X == secondvertex.X) &&
(firstvertex.Y == secondvertex.Y))
{
secondvertex.type = VertexType.UndeadVertex;
mesh.undeads++;
}
} while ((firstvertex.X == secondvertex.X) &&
(firstvertex.Y == secondvertex.Y));
lefttri.SetOrg(firstvertex);
lefttri.SetDest(secondvertex);
righttri.SetOrg(secondvertex);
righttri.SetDest(firstvertex);
lefttri.Lprev(ref bottommost);
lastvertex = secondvertex;
while (heapsize > 0)
{
nextevent = eventheap[0];
HeapDelete(eventheap, heapsize, 0);
heapsize--;
check4events = true;
if (nextevent.xkey < mesh.bounds.Left)
{
fliptri = nextevent.otriEvent;
fliptri.Oprev(ref farlefttri);
Check4DeadEvent(ref farlefttri, eventheap, ref heapsize);
fliptri.Onext(ref farrighttri);
Check4DeadEvent(ref farrighttri, eventheap, ref heapsize);
if (farlefttri.Equal(bottommost))
{
fliptri.Lprev(ref bottommost);
}
mesh.Flip(ref fliptri);
fliptri.SetApex(null);
fliptri.Lprev(ref lefttri);
fliptri.Lnext(ref righttri);
lefttri.Sym(ref farlefttri);
if (randomnation(SAMPLERATE) == 0)
{
fliptri.Sym();
leftvertex = fliptri.Dest();
midvertex = fliptri.Apex();
rightvertex = fliptri.Org();
splayroot = CircleTopInsert(splayroot, lefttri, leftvertex, midvertex, rightvertex,
nextevent.ykey);
}
}
else
{
nextvertex = nextevent.vertexEvent;
if ((nextvertex.X == lastvertex.X) &&
(nextvertex.Y == lastvertex.Y))
{
nextvertex.type = VertexType.UndeadVertex;
mesh.undeads++;
check4events = false;
}
else
{
lastvertex = nextvertex;
splayroot = FrontLocate(splayroot, bottommost, nextvertex, ref searchtri, ref farrightflag);
//bottommost.Copy(ref searchtri);
//farrightflag = false;
//while (!farrightflag && RightOfHyperbola(ref searchtri, nextvertex))
//{
// searchtri.OnextSelf();
// farrightflag = searchtri.Equal(bottommost);
//}
Check4DeadEvent(ref searchtri, eventheap, ref heapsize);
searchtri.Copy(ref farrighttri);
searchtri.Sym(ref farlefttri);
mesh.MakeTriangle(ref lefttri);
mesh.MakeTriangle(ref righttri);
connectvertex = farrighttri.Dest();
lefttri.SetOrg(connectvertex);
lefttri.SetDest(nextvertex);
righttri.SetOrg(nextvertex);
righttri.SetDest(connectvertex);
lefttri.Bond(ref righttri);
lefttri.Lnext();
righttri.Lprev();
lefttri.Bond(ref righttri);
lefttri.Lnext();
righttri.Lprev();
lefttri.Bond(ref farlefttri);
righttri.Bond(ref farrighttri);
if (!farrightflag && farrighttri.Equal(bottommost))
{
lefttri.Copy(ref bottommost);
}
if (randomnation(SAMPLERATE) == 0)
{
splayroot = SplayInsert(splayroot, lefttri, nextvertex);
}
else if (randomnation(SAMPLERATE) == 0)
{
righttri.Lnext(ref inserttri);
splayroot = SplayInsert(splayroot, inserttri, nextvertex);
}
}
}
if (check4events)
{
leftvertex = farlefttri.Apex();
midvertex = lefttri.Dest();
rightvertex = lefttri.Apex();
lefttest = RobustPredicates.CounterClockwise(leftvertex, midvertex, rightvertex);
if (lefttest > 0.0)
{
newevent = new SweepEvent();
newevent.xkey = xminextreme;
newevent.ykey = CircleTop(leftvertex, midvertex, rightvertex, lefttest);
newevent.otriEvent = lefttri;
HeapInsert(eventheap, heapsize, newevent);
heapsize++;
lefttri.SetOrg(new SweepEventVertex(newevent));
}
leftvertex = righttri.Apex();
midvertex = righttri.Org();
rightvertex = farrighttri.Apex();
righttest = RobustPredicates.CounterClockwise(leftvertex, midvertex, rightvertex);
if (righttest > 0.0)
{
newevent = new SweepEvent();
newevent.xkey = xminextreme;
newevent.ykey = CircleTop(leftvertex, midvertex, rightvertex, righttest);
newevent.otriEvent = farrighttri;
HeapInsert(eventheap, heapsize, newevent);
heapsize++;
farrighttri.SetOrg(new SweepEventVertex(newevent));
}
}
}
splaynodes.Clear();
bottommost.Lprev();
mesh.hullsize = RemoveGhosts(ref bottommost);
return(mesh);
}