message: Fix loading mtl file when obj is located in CWD
diff: @@ -302,7 +302,15 @@ void load_obj(std::string const& filename, model& mod)
  boost::filesystem::path p(filename);
  std::string mtl_dir = p.parent_path().string();
  - std::string mtl_path = mtl_dir + "/" + std::string(mtl_file.begin(), mtl_file.length());
  + std::string mtl_path = "";
  + if (mtl_dir.empty())
  + {
  + mtl_path = std::string(mtl_file.begin(), mtl_file.length());
  + }
  + else
  + {
  + mtl_path = mtl_dir + "/" + std::string(mtl_file.begin(), mtl_file.length());
  + }
  if (boost::filesystem::exists(mtl_path))
  {
  