Retrieve the face(s) adjacent to an edge in a 2D triangulation

[stla]

Hello,

I want to construct a 2D triangulation by providing the vertices and the faces. Then, for each edge, I want to get the indices of the two faces adjacent to this edge or the index of the unique adjacent face if this is a border edge.

Actually I know how to do but this does not sound serious: I add a third coordinate z=0 to each vertex and I construct a flat 3D mesh which represents my 2D triangulation, using the same triplets of indices for the faces. Then I know how to do with the 3D mesh. I iterate over the edges, and for each edge I take its halfedge(s) and the incident face(s).

I looked at the doc about the 2D triangulations and I didn't find how to find for each edge its incident face(s).

[stla]

Wait... maybe we can do a surface mesh with 2D points ?? I'm going to try.

[stla]

Yeah, this seems to work.