MESH EDGES:

Since LaGriT does not really store mesh edges, the mesh edge data
structure (MeshEdge, PMeshEdge) is created on the fly whenever edge
information is requested. Therefore after utilizing the edge(s) get
information, it (they) should be destroyed by calling ME_Delete
operator.

int ME_Number(PMeshObj mesh, PMeshEdge e);

** This will return 0 for now since I haven't yet decided on a good
** way to assign a unique number to the (virtual) edges of the mesh.

void ME_Delete(PMeshEdge e);

Free the data structure associated with this edge created on the fly.
(There is an operator for creation but I cannot yet imagine needing to
make that a publicly available operator).

** IMPORTANT **
ME_Delete will not remove any connections in the mesh. It just destroys the
temporary data structure used to store the edge info

int ME_IsParent(PMeshObj mesh, PMeshEdge pe);

If both vertices of the edge are parents, the edge is a parent.

PMeshEdge ME_Parent(PMeshObj mesh, PMeshEdge pe);

The parents of each vertex of the edge are obtained and a new 'parent'
edge is constructed from them.

void ME_Children(PMeshObj mesh, PMeshEdge pe, int *nec, PMeshEdge **ec);

*** NOT YET IMPLEMENTED ***

Child vertices of the face are found and appropriate combinations of these vertices are used to construct the new 'child' faces. For a combination to be appropriate, the vertices of the child face has to point to the same material region.

int MEs_areSame(PMeshEdge e1, PMeshEdge e2);

Compare the data in two MeshEdge data structures and see if they
represent the same connection in the mesh. This operator is needed
since the on-the-fly PMeshEdge pointers may not be the same and they
do not directly point to any persistent "object" in the database.

PGeomEntity ME_GMentity(PMeshObj mesh, PMeshEdge e);

Return the geometric model entity the edge is on. In the absence of explicit
edge representation in the database, this may be problematic in a few cases
cases where multiple classifications are possible.

GType ME_GMtype(PMeshObj mesh, PMeshEdge e);

Return the type of geometric model entity the edge is on. This (I
think) is more deterministically found from the classifications of its
vertices but still there may be some incorrect cases. The way around
is complicated and will not be implemented for now.

PMeshVert ME_Vertex(PMeshObj mesh, PMeshEdge e, int i);

Return the i'th vertex of the mesh edge. i can only be 0 or 1.
Parent edges return parent vertices and child edges return child vertices.
If a vertex is not on an interface the vertex itself is returned.

PMeshVert ME_OtherVertex(PMeshObj mesh, PMeshEdge e, PMeshVert v);

Return the other vertex of the mesh edge (obviously the one that is not v).

void ME_Faces(PMeshObj mesh, PMeshEdge e, int *nef, PMeshFace **efaces);

Get the "faces" of an "edge". The faces data structures are also
constructed on the fly since they do not exist in the LaGriT
database. Also, as with other upward connectivity queries, this can
execute usefully only if the routine MESH_BldUpAdj is called
beforehand. Also, see note on freeing the PMeshFace structures listed
under MV_Edges and MV_Faces.

The behavior of this operator for parent and child edges is similar to
MV_Edges.

void ME_Regions(PMeshObj mesh, PMeshEdge e, int *ner, PMeshRegn **eregions);

Get the regions connected to an edge. MESH_BldUpAdj must be called before this operator can be called usefully.

The behavior of this operator for child and parent edges is similar to
that of MV_Regions.

** IMPORTANT **

Since MESH_BldUpAdj builds explicit upward adjacency information, this
routine does not require a seed region to be provided. Also, this
routine will work regardless of whether there is a complete cycle of
regions around the edge and whether the edge is an arbitrary type of
non-manifold edge!!

int ME_EntOnBdry(PMeshObj mesh, PMeshEdge pe, PMeshVerte pv);

Check if vertex is on the boundary of edge. In other words, is this
vertex one of the edges vertices.