meshFaceEdges

MESHFACEEDGES Computes edge indices of each face.

   FE = meshFaceEdges(V, E, F)
   Returns a 1-by-NF cell array containing for each face, the set of edge
   indices corresponding to adjacent edges.

   Example
   meshFaceEdges

   See also
     meshes3d, meshEdgeFaces

0001 function FE = meshFaceEdges(vertices, edges, faces)
0002 %MESHFACEEDGES Computes edge indices of each face.
0003 %
0004 %   FE = meshFaceEdges(V, E, F)
0005 %   Returns a 1-by-NF cell array containing for each face, the set of edge
0006 %   indices corresponding to adjacent edges.
0007 %
0008 %   Example
0009 %   meshFaceEdges
0010 %
0011 %   See also
0012 %     meshes3d, meshEdgeFaces
0013 
0014 % ------
0015 % Author: David Legland
0016 % E-mail: david.legland@inrae.fr
0017 % Created: 2013-08-22, using Matlab 7.9.0.529 (R2009b)
0018 % Copyright 2013-2024 INRA - Cepia Software Platform
0019 
0020 nFaces = meshFaceNumber(vertices, faces);
0021 
0022 FE = cell(nFaces, 1);
0023 
0024 % impose ordering of edge indices
0025 edges = sort(edges, 2);
0026 
0027 for iFace = 1:nFaces
0028     % extract vertex indices of current face
0029     face = meshFace(faces, iFace);
0030     nv = length(face);
0031     
0032     % for each couple of adjacent vertices, find the index of the matching
0033     % row in the edges array
0034     fei = zeros(1, nv);
0035     for iEdge = 1:nv
0036         % compute index of each edge vertex
0037         edge = sort([face(iEdge) face(mod(iEdge, nv) + 1)]);
0038         v1 = edge(1);
0039         v2 = edge(2);
0040 
0041         % find the matching row
0042         ind = find(edges(:,1) == v1 & edges(:,2) == v2);
0043         fei(iEdge) = ind;
0044         
0045     end
0046     FE{iFace} = fei;
0047 end