freesurfer_write_surf

 freesurfer_write_surf - FreeSurfer I/O function to write a surface file
 
 freesurfer_write_surf(fname, vert, face)
 
 writes a surface triangulation into a binary file
 fname - name of file to write
 vert  - Nx3 matrix of vertex coordinates
 face  - Mx3 matrix of face triangulation indices
 
 The face matrix here must be matlab compatible
 (no zero indices).  It is converted to FreeSurfer
 indices that start at zero.
 
 See also freesurfer_read_surf, freesurfer_write_curv, freesurfer_write_wfile

0001 function freesurfer_write_surf(fname, vert, face)
0002 
0003 % freesurfer_write_surf - FreeSurfer I/O function to write a surface file
0004 %
0005 % freesurfer_write_surf(fname, vert, face)
0006 %
0007 % writes a surface triangulation into a binary file
0008 % fname - name of file to write
0009 % vert  - Nx3 matrix of vertex coordinates
0010 % face  - Mx3 matrix of face triangulation indices
0011 %
0012 % The face matrix here must be matlab compatible
0013 % (no zero indices).  It is converted to FreeSurfer
0014 % indices that start at zero.
0015 %
0016 % See also freesurfer_read_surf, freesurfer_write_curv, freesurfer_write_wfile
0017 
0018 if(nargin ~= 3)
0019   fprintf('USAGE: freesurfer_write_surf(fname, vert, face)\n');
0020   return;
0021 end
0022 
0023 if size(vert,2) ~= 3,
0024     error('vert must be Nx3 matrix');
0025 end
0026 
0027 if size(face,2) ~= 3,
0028     error('face must be Mx3 matrix');
0029 end
0030 
0031 fprintf('...subtracting 1 from face indices for FreeSurfer compatibility.\n');
0032 face = face - 1;
0033 
0034 % open it as a big-endian file
0035 fid = fopen(fname, 'wb', 'b') ;
0036 
0037 TRIANGLE_FILE_MAGIC_NUMBER = 16777214 ;
0038 freesurfer_fwrite3(fid, TRIANGLE_FILE_MAGIC_NUMBER);
0039 
0040 vnum = size(vert,1) ;  % number of vertices
0041 fnum = size(face,1) ;  % number of faces
0042 
0043 % Ouput a couple of text lines with creation date
0044 str = sprintf('created from matalb on %s\n',datestr(now));
0045 fwrite(fid, str,'char');
0046 fwrite(fid, str,'char');
0047 
0048 fwrite(fid, vnum,'int32');
0049 fwrite(fid, fnum,'int32');
0050 
0051 % reshape vert into column array and write
0052 vert = reshape(vert',size(vert,1)*size(vert,2),1);
0053 fwrite(fid, vert,'float32');
0054 
0055 % reshape face into column array and write
0056 face = reshape(face',size(face,1)*size(face,2),1);
0057 fwrite(fid, face,'int32');
0058 
0059 fclose(fid) ;
0060 
0061 return