- added param 'texture_file' to the Options class, it specifies the path to the texture file

- added param 'material_file_extension' to the Options class, it specifies the material file suffix, default is ".mat" as it was before, we needed it becuase Blender expects ".mtl"
- removed default and copy constructor and destructor as well as assignment operator, because these are not necessary here, see https://en.cppreference.com/w/cpp/language/rule_of_three

(Thanks to Philipp Auersperg-Castell for the patch )

Doc/changelog.docu

@@ -8,6 +8,12 @@
 
 <tr valign=top><td><b>9.1</b> (?/?/?)</td><td>
 
+<b>IO</b>
+<ul>
+<li>OBJ writer: Added param 'texture_file' to the Options class, it specifies the path to the texture file (Thanks to Philipp Auersperg-Castell for the patch)</li>
+<li>OBJ writer: added param 'material_file_extension' to the Options class, it specifies the material file suffix, default is ".mat" as it was before. (Thanks to Philipp Auersperg-Castell for the patch)</li>
+</ul>
+
 <b>Build System</b>
 <ul>
 <li>Removed globbing for Core and Tools library include and source files</li>

src/OpenMesh/Core/IO/Options.hh

@@ -115,31 +115,24 @@ public:
       TexCoordST     = 0x8000  ///< Write texture coordinates as ST instead of UV
   };
 
+  /// Texture filename. This will be written as
+  /// map_Kd in the OBJ writer into the material file.
+  std::string texture_file ;
+
+  /// Filename extension for material files when writing OBJs
+  /// default is currently .mat
+  std::string material_file_extension;
+
 public:
 
   /// Default constructor
-  Options() : flags_( Default )
+  Options() : texture_file(""), material_file_extension(".mat"), flags_( Default )
   { }
 
-
-  /// Copy constructor
-  Options(const Options& _opt) : flags_(_opt.flags_)
-  { }
-
-
-  /// Initializing constructor setting a single option
-  Options(Flag _flg) : flags_( _flg)
-  { }
-
-
    /// Initializing constructor setting multiple options
   Options(const value_type _flgs) : flags_( _flgs)
   { }
 
-
-  ~Options()
-  { }
-
   /// Restore state after default constructor.
   void cleanup(void)
   { flags_ = Default; }
@@ -154,17 +147,9 @@ public:
 public:
 
 
-  //@{
-  /// Copy options defined in _rhs.
-
-  Options& operator = ( const Options& _rhs )
-  { flags_ = _rhs.flags_; return *this; }
-
   Options& operator = ( const value_type _rhs )
   { flags_ = _rhs; return *this; }
 
-  //@}
-
 
   //@{
   /// Unset options defined in _rhs.

src/OpenMesh/Core/IO/writer/OBJWriter.cc

@@ -195,6 +195,9 @@ writeMaterial(std::ostream& _out, BaseExporter& _be, Options _opt) const
       _out << "illum 1" << '\n';
     }
 
+  if (_opt.texture_file != "") {
+      _out << "map_Kd " << _opt.texture_file << std::endl;
+  }
   return true;
 }
 
@@ -219,8 +222,10 @@ write(std::ostream& _out, BaseExporter& _be, Options _opt, std::streamsize _prec
   _out.precision(_precision);
 
   // check exporter features
-  if (!check( _be, _opt))
+  if (!check( _be, _opt)) {
       return false;
+  }
+
 
   // No binary mode for OBJ
   if ( _opt.check(Options::Binary) ) {
@@ -240,9 +245,9 @@ write(std::ostream& _out, BaseExporter& _be, Options _opt, std::streamsize _prec
   }
 
   //create material file if needed
-  if ( _opt.check(Options::FaceColor) ){
+  if ( _opt.check(Options::FaceColor) || _opt.texture_file != ""){
 
-    std::string matFile = path_ + objName_ + ".mat";
+    std::string matFile = path_ + objName_ + _opt.material_file_extension;
 
     std::fstream matStream(matFile.c_str(), std::ios_base::out );
 
@@ -262,8 +267,8 @@ write(std::ostream& _out, BaseExporter& _be, Options _opt, std::streamsize _prec
   _out << _be.n_faces() << " faces" << '\n';
 
   // material file
-  if (useMatrial &&  _opt.check(Options::FaceColor) )
+  if ( (useMatrial &&  _opt.check(Options::FaceColor)) || _opt.texture_file != "")
-    _out << "mtllib " << objName_ << ".mat" << '\n';
+    _out << "mtllib " << objName_ << _opt.material_file_extension << '\n';
 
   std::map<Vec2f,int> texMap;
   //collect Texturevertices from halfedges