calc_surface_connectivity.m

function surface_connectivity = calc_surface_connectivity(surface)
% calc_surface_connectivity.m
%
% Calculate surface-based connectivity matrix
%
% Input: surface               : surface structure with fields
%                                vertices and faces
%
% Output: surface_connectivity : surface connectivity matrix [NxN]
%
% Original: James Pang, Monash University, 2021

%%

num_vertices = size(surface.vertices, 1);
num_faces = size(surface.faces, 1);

surface_connectivity = zeros(num_vertices);

for face_ind = 1:num_faces
    face_interest = surface.faces(face_ind,:);
    
    surface_connectivity(face_interest(1), face_interest(2)) = 1;
    surface_connectivity(face_interest(1), face_interest(3)) = 1;
    surface_connectivity(face_interest(2), face_interest(3)) = 1;
end

surface_connectivity = surface_connectivity + surface_connectivity';
surface_connectivity(surface_connectivity>0) = 1;