surf_data_get_normal_vector

 get normal vector
 [USAGE]
    [normal_vector] = surf_data_get_normal_vector(<obj>);
 [IN]
    obj : surf_data object
 [OUT]
    normal_vector : normal vector

 Copyright (C) 2011, ATR All Rights Reserved.
 License : New BSD License(see VBMEG_LICENSE.txt)

0001 function [normal_vector] = surf_data_get_normal_vector(obj)
0002 % get normal vector
0003 % [USAGE]
0004 %    [normal_vector] = surf_data_get_normal_vector(<obj>);
0005 % [IN]
0006 %    obj : surf_data object
0007 % [OUT]
0008 %    normal_vector : normal vector
0009 %
0010 % Copyright (C) 2011, ATR All Rights Reserved.
0011 % License : New BSD License(see VBMEG_LICENSE.txt)
0012 
0013 %
0014 % --- Previous check
0015 %
0016 if ~exist('obj', 'var'), error('obj is a required parameter.'); end
0017 if ~strcmp(obj.class_type, 'surf_data')
0018     error('class type is invalid.');
0019 end
0020 
0021 %
0022 % --- Main Procedure
0023 %
0024 normal_vector = obj.xx;