function varargout = parseMeshData(varargin)
%PARSEMESHDATA Conversion of data representation for meshes.
%
%   MESH = parseMeshData(VERTICES, FACES)
%   MESH = parseMeshData(VERTICES, EDGES, FACES)
%   Returns the mesh info into a single structure with fields "vertices",
%   "edges" and "faces".
%
%   [VERTICES, FACES] = parseMeshData(MESH)
%   Returns the mesh info into two output variables containing coordinates
%   of vertices (as a Nv_by_3 array) and the list of vertex indices for
%   each face (either as a Nf-by-3 or Nf-by-4 int array, or as a cell
%   array).
%
%   [VERTICES, EDGES, FACES] = parseMeshData(MESH)
%   Also returns the vertex indices of each edge, as a Ne-by-2 array of
%   vertex indices.
%
%   See also
%   meshes3d, formatMeshOutput
%

% ------
% Author: David Legland
% e-mail: david.legland@inra.fr
% Created: 2010-12-06,    using Matlab 7.9.0.529 (R2009b)
% Copyright 2010 INRA - Cepia Software Platform.

% initialize edges to empty variable
edges = [];

% Process input arguments
switch nargin
    case 1
        % input is a data structure
        mesh = varargin{1};
        vertices = mesh.vertices;
        faces = mesh.faces;
        if isfield(mesh, 'edges')
            edges = mesh.edges;
        end
        
    case 2
        % input are vertices and faces
        vertices = varargin{1};
        faces = varargin{2};
   
    case  3
        % input are vertices, edges and faces
        vertices = varargin{1};
        edges = varargin{2};
        faces = varargin{3};
        
    otherwise
        error('Wrong number of arguments');
end

% returns either a struct or several variables
varargout = formatMeshOutput(nargout, vertices, edges, faces);