/// <summary>
/// Spread the virus from all infected triangles to any neighbors not
/// protected by subsegments. Delete all infected triangles.
/// </summary>
/// <remarks>
/// This is the procedure that actually creates holes and concavities.
///
/// This procedure operates in two phases. The first phase identifies all
/// the triangles that will die, and marks them as infected. They are
/// marked to ensure that each triangle is added to the virus pool only
/// once, so the procedure will terminate.
///
/// The second phase actually eliminates the infected triangles. It also
/// eliminates orphaned vertices.
/// </remarks>
void Plague()
{
Otri testtri = default(Otri);
Otri neighbor = default(Otri);
Osub neighborsubseg = default(Osub);
Vertex testvertex;
Vertex norg, ndest;
bool killorg;
// Loop through all the infected triangles, spreading the virus to
// their neighbors, then to their neighbors' neighbors.
for (int i = 0; i < viri.Count; i++)
{
// WARNING: Don't use foreach, mesh.viri list may get modified.
testtri.triangle = viri[i];
// A triangle is marked as infected by messing with one of its pointers
// to subsegments, setting it to an illegal value. Hence, we have to
// temporarily uninfect this triangle so that we can examine its
// adjacent subsegments.
// TODO: Not true in the C# version (so we could skip this).
testtri.Uninfect();
// Check each of the triangle's three neighbors.
for (testtri.orient = 0; testtri.orient < 3; testtri.orient++)
{
// Find the neighbor.
testtri.Sym(ref neighbor);
// Check for a subsegment between the triangle and its neighbor.
testtri.SegPivot(ref neighborsubseg);
// Check if the neighbor is nonexistent or already infected.
if ((neighbor.triangle == Mesh.dummytri) || neighbor.IsInfected())
{
if (neighborsubseg.seg != Mesh.dummysub)
{
// There is a subsegment separating the triangle from its
// neighbor, but both triangles are dying, so the subsegment
// dies too.
mesh.SubsegDealloc(neighborsubseg.seg);
if (neighbor.triangle != Mesh.dummytri)
{
// Make sure the subsegment doesn't get deallocated again
// later when the infected neighbor is visited.
neighbor.Uninfect();
neighbor.SegDissolve();
neighbor.Infect();
}
}
}
else
{ // The neighbor exists and is not infected.
if (neighborsubseg.seg == Mesh.dummysub)
{
// There is no subsegment protecting the neighbor, so
// the neighbor becomes infected.
neighbor.Infect();
// Ensure that the neighbor's neighbors will be infected.
viri.Add(neighbor.triangle);
}
else
{
// The neighbor is protected by a subsegment.
// Remove this triangle from the subsegment.
neighborsubseg.TriDissolve();
// The subsegment becomes a boundary. Set markers accordingly.
if (neighborsubseg.seg.boundary == 0)
{
neighborsubseg.seg.boundary = 1;
}
norg = neighbor.Org();
ndest = neighbor.Dest();
if (norg.mark == 0)
{
norg.mark = 1;
}
if (ndest.mark == 0)
{
ndest.mark = 1;
}
}
}
}
// Remark the triangle as infected, so it doesn't get added to the
// virus pool again.
testtri.Infect();
}
foreach (var virus in viri)
{
testtri.triangle = virus;
// Check each of the three corners of the triangle for elimination.
// This is done by walking around each vertex, checking if it is
// still connected to at least one live triangle.
for (testtri.orient = 0; testtri.orient < 3; testtri.orient++)
{
testvertex = testtri.Org();
// Check if the vertex has already been tested.
if (testvertex != null)
{
killorg = true;
// Mark the corner of the triangle as having been tested.
testtri.SetOrg(null);
// Walk counterclockwise about the vertex.
testtri.Onext(ref neighbor);
// Stop upon reaching a boundary or the starting triangle.
while ((neighbor.triangle != Mesh.dummytri) &&
(!neighbor.Equal(testtri)))
{
if (neighbor.IsInfected())
{
// Mark the corner of this triangle as having been tested.
neighbor.SetOrg(null);
}
else
{
// A live triangle. The vertex survives.
killorg = false;
}
// Walk counterclockwise about the vertex.
neighbor.OnextSelf();
}
// If we reached a boundary, we must walk clockwise as well.
if (neighbor.triangle == Mesh.dummytri)
{
// Walk clockwise about the vertex.
testtri.Oprev(ref neighbor);
// Stop upon reaching a boundary.
while (neighbor.triangle != Mesh.dummytri)
{
if (neighbor.IsInfected())
{
// Mark the corner of this triangle as having been tested.
neighbor.SetOrg(null);
}
else
{
// A live triangle. The vertex survives.
killorg = false;
}
// Walk clockwise about the vertex.
neighbor.OprevSelf();
}
}
if (killorg)
{
// Deleting vertex
testvertex.type = VertexType.UndeadVertex;
mesh.undeads++;
}
}
}
// Record changes in the number of boundary edges, and disconnect
// dead triangles from their neighbors.
for (testtri.orient = 0; testtri.orient < 3; testtri.orient++)
{
testtri.Sym(ref neighbor);
if (neighbor.triangle == Mesh.dummytri)
{
// There is no neighboring triangle on this edge, so this edge
// is a boundary edge. This triangle is being deleted, so this
// boundary edge is deleted.
mesh.hullsize--;
}
else
{
// Disconnect the triangle from its neighbor.
neighbor.Dissolve();
// There is a neighboring triangle on this edge, so this edge
// becomes a boundary edge when this triangle is deleted.
mesh.hullsize++;
}
}
// Return the dead triangle to the pool of triangles.
mesh.TriangleDealloc(testtri.triangle);
}
// Empty the virus pool.
viri.Clear();
}
/// <summary>
/// Find the holes and infect them. Find the area constraints and infect
/// them. Infect the convex hull. Spread the infection and kill triangles.
/// Spread the area constraints.
/// </summary>
public void CarveHoles()
{
Otri searchtri = default(Otri);
Vertex searchorg, searchdest;
LocateResult intersect;
Triangle[] regionTris = null;
if (!mesh.behavior.Convex)
{
// Mark as infected any unprotected triangles on the boundary.
// This is one way by which concavities are created.
InfectHull();
}
if (!mesh.behavior.NoHoles)
{
// Infect each triangle in which a hole lies.
foreach (var hole in mesh.holes)
{
// Ignore holes that aren't within the bounds of the mesh.
if (mesh.bounds.Contains(hole))
{
// Start searching from some triangle on the outer boundary.
searchtri.triangle = Mesh.dummytri;
searchtri.orient = 0;
searchtri.SymSelf();
// Ensure that the hole is to the left of this boundary edge;
// otherwise, locate() will falsely report that the hole
// falls within the starting triangle.
searchorg = searchtri.Org();
searchdest = searchtri.Dest();
if (Primitives.CounterClockwise(searchorg, searchdest, hole) > 0.0)
{
// Find a triangle that contains the hole.
intersect = mesh.locator.Locate(hole, ref searchtri);
if ((intersect != LocateResult.Outside) && (!searchtri.IsInfected()))
{
// Infect the triangle. This is done by marking the triangle
// as infected and including the triangle in the virus pool.
searchtri.Infect();
viri.Add(searchtri.triangle);
}
}
}
}
}
// Now, we have to find all the regions BEFORE we carve the holes, because locate() won't
// work when the triangulation is no longer convex. (Incidentally, this is the reason why
// regional attributes and area constraints can't be used when refining a preexisting mesh,
// which might not be convex; they can only be used with a freshly triangulated PSLG.)
if (mesh.regions.Count > 0)
{
int i = 0;
regionTris = new Triangle[mesh.regions.Count];
// Find the starting triangle for each region.
foreach (var region in mesh.regions)
{
regionTris[i] = Mesh.dummytri;
// Ignore region points that aren't within the bounds of the mesh.
if (mesh.bounds.Contains(region.point))
{
// Start searching from some triangle on the outer boundary.
searchtri.triangle = Mesh.dummytri;
searchtri.orient = 0;
searchtri.SymSelf();
// Ensure that the region point is to the left of this boundary
// edge; otherwise, locate() will falsely report that the
// region point falls within the starting triangle.
searchorg = searchtri.Org();
searchdest = searchtri.Dest();
if (Primitives.CounterClockwise(searchorg, searchdest, region.point) > 0.0)
{
// Find a triangle that contains the region point.
intersect = mesh.locator.Locate(region.point, ref searchtri);
if ((intersect != LocateResult.Outside) && (!searchtri.IsInfected()))
{
// Record the triangle for processing after the
// holes have been carved.
regionTris[i] = searchtri.triangle;
regionTris[i].region = region.id;
}
}
}
i++;
}
}
if (viri.Count > 0)
{
// Carve the holes and concavities.
Plague();
}
if (regionTris != null)
{
var iterator = new RegionIterator(mesh);
for (int i = 0; i < regionTris.Length; i++)
{
if (regionTris[i] != Mesh.dummytri)
{
// Make sure the triangle under consideration still exists.
// It may have been eaten by the virus.
if (!Otri.IsDead(regionTris[i]))
{
// Apply one region's attribute and/or area constraint.
iterator.Process(regionTris[i]);
}
}
}
}
// Free up memory (virus pool should be empty anyway).
viri.Clear();
}
public void CarveHoles()
{
Otri otri = new Otri();
Triangle[] triangleArray = null;
if (!this.mesh.behavior.Convex)
{
this.InfectHull();
}
if (!this.mesh.behavior.NoHoles)
{
foreach (Point hole in this.mesh.holes)
{
if (!this.mesh.bounds.Contains(hole))
{
continue;
}
otri.triangle = Mesh.dummytri;
otri.orient = 0;
otri.SymSelf();
if (Primitives.CounterClockwise(otri.Org(), otri.Dest(), hole) <= 0 || this.mesh.locator.Locate(hole, ref otri) == LocateResult.Outside || otri.IsInfected())
{
continue;
}
otri.Infect();
this.viri.Add(otri.triangle);
}
}
if (this.mesh.regions.Count > 0)
{
int num = 0;
triangleArray = new Triangle[this.mesh.regions.Count];
foreach (RegionPointer region in this.mesh.regions)
{
triangleArray[num] = Mesh.dummytri;
if (this.mesh.bounds.Contains(region.point))
{
otri.triangle = Mesh.dummytri;
otri.orient = 0;
otri.SymSelf();
if (Primitives.CounterClockwise(otri.Org(), otri.Dest(), region.point) > 0 && this.mesh.locator.Locate(region.point, ref otri) != LocateResult.Outside && !otri.IsInfected())
{
triangleArray[num] = otri.triangle;
triangleArray[num].region = region.id;
}
}
num++;
}
}
if (this.viri.Count > 0)
{
this.Plague();
}
if (triangleArray != null)
{
RegionIterator regionIterator = new RegionIterator(this.mesh);
for (int i = 0; i < (int)triangleArray.Length; i++)
{
if (triangleArray[i] != Mesh.dummytri && !Otri.IsDead(triangleArray[i]))
{
regionIterator.Process(triangleArray[i]);
}
}
}
this.viri.Clear();
}
/// <summary>
/// Virally infect all of the triangles of the convex hull that are not
/// protected by subsegments. Where there are subsegments, set boundary
/// markers as appropriate.
/// </summary>
private void InfectHull()
{
Otri hulltri = default(Otri);
Otri nexttri = default(Otri);
Otri starttri = default(Otri);
Osub hullsubseg = default(Osub);
Vertex horg, hdest;
// Find a triangle handle on the hull.
hulltri.triangle = Mesh.dummytri;
hulltri.orient = 0;
hulltri.SymSelf();
// Remember where we started so we know when to stop.
hulltri.Copy(ref starttri);
// Go once counterclockwise around the convex hull.
do
{
// Ignore triangles that are already infected.
if (!hulltri.IsInfected())
{
// Is the triangle protected by a subsegment?
hulltri.SegPivot(ref hullsubseg);
if (hullsubseg.seg == Mesh.dummysub)
{
// The triangle is not protected; infect it.
if (!hulltri.IsInfected())
{
hulltri.Infect();
viri.Add(hulltri.triangle);
}
}
else
{
// The triangle is protected; set boundary markers if appropriate.
if (hullsubseg.seg.boundary == 0)
{
hullsubseg.seg.boundary = 1;
horg = hulltri.Org();
hdest = hulltri.Dest();
if (horg.mark == 0)
{
horg.mark = 1;
}
if (hdest.mark == 0)
{
hdest.mark = 1;
}
}
}
}
// To find the next hull edge, go clockwise around the next vertex.
hulltri.LnextSelf();
hulltri.Oprev(ref nexttri);
while (nexttri.triangle != Mesh.dummytri)
{
nexttri.Copy(ref hulltri);
hulltri.Oprev(ref nexttri);
}
} while (!hulltri.Equal(starttri));
}
private void Plague()
{
Otri item = new Otri();
Otri otri = new Otri();
Osub osub = new Osub();
for (int i = 0; i < this.viri.Count; i++)
{
item.triangle = this.viri[i];
item.Uninfect();
item.orient = 0;
while (item.orient < 3)
{
item.Sym(ref otri);
item.SegPivot(ref osub);
if (otri.triangle != Mesh.dummytri && !otri.IsInfected())
{
if (osub.seg != Mesh.dummysub)
{
osub.TriDissolve();
if (osub.seg.boundary == 0)
{
osub.seg.boundary = 1;
}
Vertex vertex = otri.Org();
Vertex vertex1 = otri.Dest();
if (vertex.mark == 0)
{
vertex.mark = 1;
}
if (vertex1.mark == 0)
{
vertex1.mark = 1;
}
}
else
{
otri.Infect();
this.viri.Add(otri.triangle);
}
}
else if (osub.seg != Mesh.dummysub)
{
this.mesh.SubsegDealloc(osub.seg);
if (otri.triangle != Mesh.dummytri)
{
otri.Uninfect();
otri.SegDissolve();
otri.Infect();
}
}
item.orient = item.orient + 1;
}
item.Infect();
}
foreach (Triangle virus in this.viri)
{
item.triangle = virus;
item.orient = 0;
while (item.orient < 3)
{
Vertex vertex2 = item.Org();
if (vertex2 != null)
{
bool flag = true;
item.SetOrg(null);
item.Onext(ref otri);
while (otri.triangle != Mesh.dummytri && !otri.Equal(item))
{
if (!otri.IsInfected())
{
flag = false;
}
else
{
otri.SetOrg(null);
}
otri.OnextSelf();
}
if (otri.triangle == Mesh.dummytri)
{
item.Oprev(ref otri);
while (otri.triangle != Mesh.dummytri)
{
if (!otri.IsInfected())
{
flag = false;
}
else
{
otri.SetOrg(null);
}
otri.OprevSelf();
}
}
if (flag)
{
vertex2.type = VertexType.UndeadVertex;
Mesh mesh = this.mesh;
mesh.undeads = mesh.undeads + 1;
}
}
item.orient = item.orient + 1;
}
item.orient = 0;
while (item.orient < 3)
{
item.Sym(ref otri);
if (otri.triangle != Mesh.dummytri)
{
otri.Dissolve();
Mesh mesh1 = this.mesh;
mesh1.hullsize = mesh1.hullsize + 1;
}
else
{
Mesh mesh2 = this.mesh;
mesh2.hullsize = mesh2.hullsize - 1;
}
item.orient = item.orient + 1;
}
this.mesh.TriangleDealloc(item.triangle);
}
this.viri.Clear();
}
