RAMONVolume to .obj conversion

RAMON2obj.m

function RAMON2obj(matrix_or_ramon, id, show)
%% TO_OBJ Convert an annotation to a 3D .obj file
%   For use with CAJAL (https://github.com/openconnectome/cajal)
%   Pass an anno'd RAMONVolume or its data
%   and this will export a file called
%   `export-{id}.obj` that contains a mesh
%   of the selected anno, where {id} is the
%   id that was exported.
%   TO_OBJ(matrix, id)  Convert annotation #id from matrix.data to .obj
%   TO_OBJ(matrix, id, 1) SLOW! Convert as above, but show first

if nargin < 3
    show = 0;
end

if isa(matrix_or_ramon, 'RAMONVolume')
    mat = matrix_or_ramon.data;
else
    mat = matrix_or_ramon;
end


p = patch(isosurface(mat ~= id, 0));
n = isonormals(mat, p);

if show
    p.FaceColor = 'red';
    p.EdgeColor = 'none';
    daspect([1,1,1])
    view(3); axis tight
    camlight
    lighting gouraud
end

vs = p.Vertices;
fs = p.Faces;


f = fopen(['export-' int2str(id) '.obj'], 'w');
fprintf(f, ['# Generated by MATLAB RAMON2obj' ...
            '\n# on ' date '. Script by @j6k4m8.\n']);
for ii = 1:length(vs)
    fprintf(f, 'v %d %d %d\n', vs(ii,:));
end

for ii = 1:length(fs)
    fprintf(f, 'f %d %d %d\n', fs(ii,:));
end
fclose(f);


end