Mesh Oriented datABase  (version 5.5.1)
An array-based unstructured mesh library
ReadSTL.hpp
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1 /**
2  * MOAB, a Mesh-Oriented datABase, is a software component for creating,
3  * storing and accessing finite element mesh data.
4  *
5  * Copyright 2004 Sandia Corporation. Under the terms of Contract
6  * DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government
7  * retains certain rights in this software.
8  *
9  * This library is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  */
15 
16 #ifndef READ_STL_HPP
17 #define READ_STL_HPP
18 
19 #include <cstdio>
20 #include "moab/Forward.hpp"
21 #include "moab/ReaderIface.hpp"
22 
23 namespace moab
24 {
25 
26 class ReadUtilIface;
27 
28 /**
29  * \brief ASCII and Binary Stereo Lithography File readers.
30  * \author Jason Kraftcheck
31  *
32  * STL files contain no connectivity infomration. Each triangle
33  * is specified as by three sets of single-precision coordinate
34  * triples. This reader does not use ANY tolerance when comparing
35  * vertex locations to recover connectivity. The points must be
36  * EXACTLY equal (including the sign on zero values.) If the file
37  * was written by an application which represented connectivity
38  * explicitly, there is no reason for the vertex coordinates to
39  * be anything other than exactly equal.
40  *
41  * For binary STL files, the defacto standard is that they be written
42  * with a little-endian byte order. The reader will attempt to
43  * determine the byte order automatically, and if it is ambiguous,
44  * will default to little-endian. The byte ordering may be forced by
45  * by creating an integer tag named "__STL_BYTE_ORDER" and setting a
46  * global/mesh value for the tag as 1 for big-endian or 0 for
47  * little-endian.
48  *
49  * For binary files, this reader relies on the file size to determine
50  * the validity of the file and may use it in guessing the byte order.
51  * This should not be an issue, as the file size can be determined
52  * exactly from the number of triangles for a valid file. However, if
53  * for some reason the file is readable even though it is invalid (e.g.
54  * it is some hybrid file with STL data in the beginning and some app-
55  * specific data appended to the end of the file) the check on the file
56  * size can be disabled by giving the reader a something other than a
57  * regular file to read from. For example, on Unix-like systems, have
58  * the reader read from a FIFO instead of a file:
59  * mkfifo /tmp/fifo.stlb
60  * cat my_binary_file.stlb > /tmp/fifo.stlb
61  * and instruct the MOAB-based application to read from /tmp/fifo.stlb
62  */
63 class ReadSTL : public ReaderIface
64 {
65 
66  public:
67  //! factory method for STL reader
68  static ReaderIface* factory( Interface* );
69 
70  //! Generic file loading code for both binary and ASCII readers.
71  //! Calls reader-specific read_triangles function to do actual I/O.
72  ErrorCode load_file( const char* file_name,
73  const EntityHandle* file_set,
74  const FileOptions& opts,
75  const SubsetList* subset_list = 0,
76  const Tag* file_id_tag = 0 );
77 
78  ErrorCode read_tag_values( const char* file_name,
79  const char* tag_name,
80  const FileOptions& opts,
81  std::vector< int >& tag_values_out,
82  const SubsetList* subset_list = 0 );
83 
84  //! Constructor
85  ReadSTL( Interface* impl = NULL );
86 
87  //! Destructor
88  virtual ~ReadSTL();
89 
90  // An object to hold vertex coordinates, and an operator
91  // for storing them in a STL tree-based container.
92  struct Point
93  {
94  float coords[3];
95  bool operator<( const Point& ) const;
96  };
97  // Data returned by read_triangles.
98  struct Triangle
99  {
100  Point points[3];
101  };
102 
103  enum ByteOrder
104  {
105  STL_BIG_ENDIAN,
106  STL_LITTLE_ENDIAN,
107  STL_UNKNOWN_BYTE_ORDER
108  };
109 
110  protected:
111  // I/O specific part of reader - read ASCII file
112  ErrorCode ascii_read_triangles( const char* file_name, std::vector< Triangle >& tris_out );
113 
114  // I/O specific part of reader - read binary file
115  ErrorCode binary_read_triangles( const char* file_name, ByteOrder byte_order, std::vector< Triangle >& tris_out );
116 
117  ReadUtilIface* readMeshIface;
118 
119  //! interface instance
120  Interface* mdbImpl;
121 };
122 
123 } // namespace moab
124 
125 #endif