private int RemoveGhosts(ref Otri startghost)
{
Otri otri = new Otri();
Otri otri1 = new Otri();
Otri otri2 = new Otri();
bool poly = !this.mesh.behavior.Poly;
startghost.Lprev(ref otri);
otri.SymSelf();
Mesh.dummytri.neighbors[0] = otri;
startghost.Copy(ref otri1);
int num = 0;
do
{
num++;
otri1.Lnext(ref otri2);
otri1.LprevSelf();
otri1.SymSelf();
if (poly && otri1.triangle != Mesh.dummytri)
{
Vertex vertex = otri1.Org();
if (vertex.mark == 0)
{
vertex.mark = 1;
}
}
otri1.Dissolve();
otri2.Sym(ref otri1);
this.mesh.TriangleDealloc(otri2.triangle);
}while (!otri1.Equal(startghost));
return(num);
}
private int RemoveBox()
{
Otri otri = new Otri();
Otri otri1 = new Otri();
Otri otri2 = new Otri();
Otri otri3 = new Otri();
Otri otri4 = new Otri();
Otri otri5 = new Otri();
bool poly = !this.mesh.behavior.Poly;
otri3.triangle = Mesh.dummytri;
otri3.orient = 0;
otri3.SymSelf();
otri3.Lprev(ref otri4);
otri3.LnextSelf();
otri3.SymSelf();
otri3.Lprev(ref otri1);
otri1.SymSelf();
otri3.Lnext(ref otri2);
otri2.SymSelf();
if (otri2.triangle == Mesh.dummytri)
{
otri1.LprevSelf();
otri1.SymSelf();
}
Mesh.dummytri.neighbors[0] = otri1;
int num = -2;
while (!otri3.Equal(otri4))
{
num++;
otri3.Lprev(ref otri5);
otri5.SymSelf();
if (poly && otri5.triangle != Mesh.dummytri)
{
Vertex vertex = otri5.Org();
if (vertex.mark == 0)
{
vertex.mark = 1;
}
}
otri5.Dissolve();
otri3.Lnext(ref otri);
otri.Sym(ref otri3);
this.mesh.TriangleDealloc(otri.triangle);
if (otri3.triangle != Mesh.dummytri)
{
continue;
}
otri5.Copy(ref otri3);
}
this.mesh.TriangleDealloc(otri4.triangle);
return(num);
}
public void TestDissolve()
{
// Outer space triangle.
var dummy = new Triangle()
{
id = -1
};
var triangles = CreateExampleMesh();
Otri s = default;
Otri t = default;
Otri tmp = default;
// The bottom left triangle with edge 1 -> 3.
s.tri = triangles[0];
s.orient = 1;
// The center triangle with edge 3 -> 1.
t.tri = triangles[1];
t.orient = 2;
// Make sure we're on the correct edges.
Assert.AreEqual(1, s.Org().ID);
Assert.AreEqual(3, s.Dest().ID);
Assert.AreEqual(3, t.Org().ID);
Assert.AreEqual(1, t.Dest().ID);
// Check that neighbors are properly set.
s.Sym(ref tmp);
Assert.AreEqual(1, tmp.tri.ID);
t.Sym(ref tmp);
Assert.AreEqual(0, tmp.tri.ID);
// Now dissolve the bond from one side.
s.Dissolve(dummy);
// Check neighbors.
s.Sym(ref tmp);
Assert.AreEqual(-1, tmp.tri.ID);
t.Sym(ref tmp);
Assert.AreEqual(0, tmp.tri.ID);
// And dissolve the bond from the other side.
t.Dissolve(dummy);
// Check neighbors.
s.Sym(ref tmp);
Assert.AreEqual(-1, tmp.tri.ID);
t.Sym(ref tmp);
Assert.AreEqual(-1, tmp.tri.ID);
}
/// <summary>
/// Removes ghost triangles.
/// </summary>
/// <param name="startghost"></param>
/// <returns>Number of vertices on the hull.</returns>
int RemoveGhosts(ref Otri startghost)
{
Otri searchedge = default(Otri);
Otri dissolveedge = default(Otri);
Otri deadtriangle = default(Otri);
Vertex markorg;
int hullsize;
bool noPoly = !mesh.behavior.Poly;
var dummytri = mesh.dummytri;
// Find an edge on the convex hull to start point location from.
startghost.Lprev(ref searchedge);
searchedge.Sym();
dummytri.neighbors[0] = searchedge;
// Remove the bounding box and count the convex hull edges.
startghost.Copy(ref dissolveedge);
hullsize = 0;
do
{
hullsize++;
dissolveedge.Lnext(ref deadtriangle);
dissolveedge.Lprev();
dissolveedge.Sym();
// If no PSLG is involved, set the boundary markers of all the vertices
// on the convex hull. If a PSLG is used, this step is done later.
if (noPoly)
{
// Watch out for the case where all the input vertices are collinear.
if (dissolveedge.tri.id != Mesh.DUMMY)
{
markorg = dissolveedge.Org();
if (markorg.label == 0)
{
markorg.label = 1;
}
}
}
// Remove a bounding triangle from a convex hull triangle.
dissolveedge.Dissolve(dummytri);
// Find the next bounding triangle.
deadtriangle.Sym(ref dissolveedge);
// Delete the bounding triangle.
mesh.TriangleDealloc(deadtriangle.tri);
} while (!dissolveedge.Equals(startghost));
return(hullsize);
}
/// <summary>
/// Remove the "infinite" bounding triangle, setting boundary markers as appropriate.
/// </summary>
/// <returns>Returns the number of edges on the convex hull of the triangulation.</returns>
/// <remarks>
/// The triangular bounding box has three boundary triangles (one for each
/// side of the bounding box), and a bunch of triangles fanning out from
/// the three bounding box vertices (one triangle for each edge of the
/// convex hull of the inner mesh). This routine removes these triangles.
/// </remarks>
int RemoveBox()
{
Otri deadtriangle = default(Otri);
Otri searchedge = default(Otri);
Otri checkedge = default(Otri);
Otri nextedge = default(Otri), finaledge = default(Otri), dissolveedge = default(Otri);
Vertex markorg;
int hullsize;
bool noPoly = !mesh.behavior.Poly;
// Find a boundary triangle.
nextedge.triangle = Mesh.dummytri;
nextedge.orient = 0;
nextedge.SymSelf();
// Mark a place to stop.
nextedge.Lprev(ref finaledge);
nextedge.LnextSelf();
nextedge.SymSelf();
// Find a triangle (on the boundary of the vertex set) that isn't
// a bounding box triangle.
nextedge.Lprev(ref searchedge);
searchedge.SymSelf();
// Check whether nextedge is another boundary triangle
// adjacent to the first one.
nextedge.Lnext(ref checkedge);
checkedge.SymSelf();
if (checkedge.triangle == Mesh.dummytri)
{
// Go on to the next triangle. There are only three boundary
// triangles, and this next triangle cannot be the third one,
// so it's safe to stop here.
searchedge.LprevSelf();
searchedge.SymSelf();
}
// Find a new boundary edge to search from, as the current search
// edge lies on a bounding box triangle and will be deleted.
Mesh.dummytri.neighbors[0] = searchedge;
hullsize = -2;
while (!nextedge.Equal(finaledge))
{
hullsize++;
nextedge.Lprev(ref dissolveedge);
dissolveedge.SymSelf();
// If not using a PSLG, the vertices should be marked now.
// (If using a PSLG, markhull() will do the job.)
if (noPoly)
{
// Be careful! One must check for the case where all the input
// vertices are collinear, and thus all the triangles are part of
// the bounding box. Otherwise, the setvertexmark() call below
// will cause a bad pointer reference.
if (dissolveedge.triangle != Mesh.dummytri)
{
markorg = dissolveedge.Org();
if (markorg.mark == 0)
{
markorg.mark = 1;
}
}
}
// Disconnect the bounding box triangle from the mesh triangle.
dissolveedge.Dissolve();
nextedge.Lnext(ref deadtriangle);
deadtriangle.Sym(ref nextedge);
// Get rid of the bounding box triangle.
mesh.TriangleDealloc(deadtriangle.triangle);
// Do we need to turn the corner?
if (nextedge.triangle == Mesh.dummytri)
{
// Turn the corner.
dissolveedge.Copy(ref nextedge);
}
}
mesh.TriangleDealloc(finaledge.triangle);
return(hullsize);
}
/// <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();
}
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();
}