function polygonal_surface_display ( node_file_name, face_file_name )

%% POLYGONAL_SURFACE_DISPLAY displays a polygonal surface file.
%
%  Modified:
%
%    18 January 2007
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string NODE_FILE_NAME, the name of the node file.
%
%    Input, string FACE_FILE_NAME, the name of the face file.
%
  timestamp;

  fprintf ( 1, '\n' );
  fprintf ( 1, 'POLYGONAL_SURFACE_DISPLAY\n' );
  fprintf ( 1, '  MATLAB version\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Read the nodes and faces defining\n' );
  fprintf ( 1, '  a polygonal surface and display the object\n' );
  fprintf ( 1, '  as a MATLAB shape.\n' );
%
%  If at least one command line argument, it's the node file name.
%
  if ( nargin < 1 )

    fprintf ( 1, '\n' );
    fprintf ( 1, 'POLYGONAL_SURFACE_DISPLAY:\n' );
    node_file_name = input ( 'Enter the name of the node file:' );

  end
%
%  If at least two command line arguments, it's the face file name.
%
  if ( nargin < 2 )

    fprintf ( 1, '\n' );
    fprintf ( 1, 'POLYGONAL_SURFACE_DISPLAY:\n' );
    face_file_name = input ( 'Enter the name of the face file:' );

  end

  [ node_num, node_xyz ] = polygonal_surface_node_file_read ( node_file_name );

  fprintf ( 1, '\n' );
  fprintf ( 1, '  Number of nodes = %d\n', node_num );

  r8mat_transpose_print_some ( 3, node_num, node_xyz, 1, 1, 3, 5, ...
    '  First five nodes:' );

  [ face_order, face_num, face_node ] = ...
    polygonal_surface_face_file_read ( face_file_name );

  fprintf ( 1, '\n' );
  fprintf ( 1, '  Face order =      %d\n', face_order );
  fprintf ( 1, '  Number of faces = %d\n', face_num );

  i4mat_transpose_print_some ( face_order, face_num, face_node, ...
    1, 1, face_order, 5, '  First five faces:' );
%
%  Display the image as a collection of polygons.
%
  handle = patch ( 'Vertices', node_xyz', 'Faces', face_node' );
  
  set ( handle, 'FaceColor', [0.5, 0.6, 0.8], 'EdgeColor', 'Black' );

  axis equal; 
  grid on;

  xlabel ( '--X axis--' )
  ylabel ( '--Y axis--' )
  zlabel ( '--Z axis--' )
%
%  The TITLE function will interpret underscores in the title.
%  We need to unescape such escape sequences!
%
  title_string = s_escape_tex ( face_file_name );
  title ( title_string )

  fprintf ( 1, '\n' );
  fprintf ( 1, 'POLYGONAL_SURFACE_DISPLAY:\n' );
  fprintf ( 1, '  Normal end of execution.\n' );

  fprintf ( 1, '\n' );
  timestamp;