display.m

a MATLAB program which reads files defining a piecewise constant triangulation of data, and displays

function obj_display ( input_file_name )

%% STLA_DISPLAY displays the faces of a shape defined by an ASCII STL file.
%
%  Usage:
%
%    obj_display ( 'file.obj' )
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    27 September 2008
%
%  Author:
%
%    John Burkardt
%
  timestamp ( );

  fprintf ( 1, '\n' );
  fprintf ( 1, 'OBJ_DISPLAY\n' );
  fprintf ( 1, '  MATLAB version\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '  Reads an object in an ASCII OBJ file.\n' );
  fprintf ( 1, '  Display it as a MATLAB shape.\n' );
%
%  If at least one command line argument, it's the input file name.
%
  if ( nargin < 1 )

    fprintf ( 1, '\n' );
    fprintf ( 1, 'OBJ_DISPLAY:\n' );
    input_file_name = input ( 'Enter the name of the input file:' );

  end
%
%  Get sizes.
%
  [ node_num, face_num, normal_num, order_max ] = obj_size ( input_file_name );
%
%  Print the sizes.
%
  obj_size_print ( input_file_name, node_num, face_num, normal_num, order_max );
%
%  Get the data.
%
  [ node_xyz, face_order, face_node, normal_vector, vertex_normal ] = ...
    obj_read ( input_file_name, node_num, face_num, normal_num, order_max );
%
%  FACE_NODE may contain polygons of different orders.
%  To make the call to PATCH, we will assume all the polygons are the same order.
%  To do so, we'll simply "stutter" the first node in each face list.
%
  for face = 1 : face_num
    face_node(face_order(face)+1:order_max,face) = face_node(1,face);
  end
%
%  If any node index is still less than 1, set the whole face to 1's.
%  We're giving up on this presumably meaningless face, but we need to
%  do it in a way that keeps MATLAB happy!
%
  for face = 1 : face_num
    for i = 1 : order_max
      face_node(i,face) = max ( face_node(i,face), 1 );
    end
  end
%
%  Display the shape.
%
  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 ( input_file_name );
  title ( title_string )

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

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

  return
end