ReadOBJ.hpp

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/**
 * MOAB, a Mesh-Oriented datABase, is a software component for creating,
 * storing and accessing finite element mesh data.
 *
 * Copyright 2004 Sandia Corporation. Under the terms of Contract
 * DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government
 * retains certain rights in this software.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 */
 
//-----------------------------------------------------------------------------
// Filename : ReadOBJ.hpp
//
// Purpose : Wavefront obj file reader
//
// Creators : Chelsea D'Angelo, Paul Wilson, Andrew Davis
//
// Date : 02/16
//
// Owner : Chelsea D'Angelo
//-----------------------------------------------------------------------------
 
/**
 * This class will read in an obj file and populate a MOAB instance with the
 * vertex and connectivity information in the file. A specification for obj files
 * can be found here: https://en.wikipedia.org/wiki/Wavefront_.obj_file
 * This reader only supports a subset of the full file structure, namely,
 * object names, group names, vertices, and faces.
 *
 * Overview of the supported structure:
 *
 * Heading
 * Object line: o object_name
 * Group line: g group_name1
 * Vertex lines: v x y z
 * Face lines (tri): f v1 v2 v3
 * Face lines (quad): f v1 v2 v3 v4
 *
 * Lines that begin w/ anything other than 'o ', 'g ', 'v ', and 'f ' are not
 * supported. If a valid, but unsupported line is found, it will be ignored.
 * If an invalid line is found, an error will be produced.
 * Face lines that contain 'vertex\texture\normal' are handled by ignoring the
 * texture and normal
 *
 *
 * A new meshset will be created for each object or group in the file.
 * Each object and group must have a name, or the line will be ignored.
 * Groups are thought to be collections of elements with no dimension or category and
 * will therefore only be assigned name and id tags.
 * Objects are thought to be closed surfaces. A surface meshset will be
 * created for each object. A volume meshset that directly corresponds
 * to the surface meshset will also be created. These will have name, id,
 * categorty, and dimension tags. A parent-child relationship exists
 * between the volume and surface meshsets.
 * Vertices will be created and added to a global vertex meshset.
 * Triangular faces will be created and added as members of the surface meshets.
 */
 
#ifndef READ_OBJ_HPP
#define READ_OBJ_HPP
 
#ifndef IS_BUILDING_MB
#error "ReadOBJ.hpp isn't supposed to be included into an application"
#endif
 
#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
#include <map>
 
#include "moab/Interface.hpp"
#include "moab/ReaderIface.hpp"
#include "FileTokenizer.hpp"
#include "moab/RangeMap.hpp"
#include "MBTagConventions.hpp"
 
/* struct vertex is a structure that stores coordinates
 of vertices. This is a convenience structure making
 i/o easier.
*/
struct vertex
{
 int vertex_id;
 double coord[3];
};
 
/* struct face is a structure that stores connectivity.
 This is a convenience structure makin i/o easier.
*/
struct face
{
 int face_id;
 moab::EntityHandle conn[3];
};
namespace moab
{
 
/* Supported obj file keywords
 */
enum keyword_type
{
 obj_undefined = 0,
 object_start,
 group_start,
 face_start,
 vertex_start,
 valid_unsupported
};
 
class ReadUtilIface;
class GeomTopoTool;
 
class ReadOBJ : public ReaderIface
{
 
 public:
 //! factory method
 static ReaderIface* factory( Interface* );
 
 ErrorCode load_file( const char* file_name,
 const EntityHandle* file_set,
 const FileOptions& opts,
 const SubsetList* subset_list = 0,
 const Tag* file_id_tag = 0 );
 
 ErrorCode read_tag_values( const char* file_name,
 const char* tag_name,
 const FileOptions& opts,
 std::vector< int >& tag_values_out,
 const SubsetList* subset_list = 0 );
 
 //! Constructor
 ReadOBJ( Interface* impl = NULL );
 
 //! Destructor
 virtual ~ReadOBJ();
 
 private:
 ReadUtilIface* readMeshIface;
 
 //! interface instance
 Interface* MBI;
 
 GeomTopoTool* myGeomTool;
 
 Tag geom_tag, id_tag, name_tag, category_tag, faceting_tol_tag, geometry_resabs_tag, obj_name_tag;
 
 /* The keyword type function matches the first character extracted from each line to a type of
 * line
 */
 keyword_type get_keyword( std::vector< std::string > tokens );
 
 /* The match function searches a list of map keys for a match with the token
 */
 template < typename T >
 std::string match( const std::string& token, std::map< std::string, T >& tokenList );
 
 /* The tokenize function takes a string as input and splits it into
 * a vector of strings based on the delimiter
 */
 static const char* delimiters;
 
 void tokenize( const std::string& str, std::vector< std::string >& tokens, const char* delimiters );
 
 /*
 * The create_object funtion will create a new meshset for
 * each object that contains all vertices and faces
 */
 ErrorCode create_new_object( std::string object_name, int object_id, EntityHandle& curr_obj_meshset );
 
 ErrorCode create_new_group( std::string object_name, int curr_object, EntityHandle& object_meshset );
 
 /* create_new_vertex converts tokenized string input to
 vertex structure
 */
 ErrorCode create_new_vertex( std::vector< std::string > v_tokens, EntityHandle& vertex_eh );
 
 /* create_new_face converts tokenized string input to
 * face structure
 */
 ErrorCode create_new_face( std::vector< std::string > f_tokens,
 const std::vector< EntityHandle >& vertex_list,
 EntityHandle& face_eh );
 
 /*
 * The split_quad function creates 1 new vertex and 4 new tri faces
 * from a quad face.
 */
 
 ErrorCode split_quad( std::vector< std::string > f_tokens,
 std::vector< EntityHandle >& vertex_list,
 Range& face_eh );
 
 ErrorCode create_tri_faces( std::vector< EntityHandle > quad_vert_eh,
 // EntityHandle center_vertex_eh,
 Range& face_eh );
};
 
} // namespace moab
 
#endif