code: def load_obj(
      f,
      load_textures: bool = True,
      create_texture_atlas: bool = False,
      texture_atlas_size: int = 4,
      texture_wrap: Optional[str] = "repeat",
      device: Device = "cpu",
      path_manager: Optional[PathManager] = None,
  ):
      """
      Load a mesh from a .obj file and optionally textures from a .mtl file.
      Currently this handles verts, faces, vertex texture uv coordinates, normals,
      texture images and material reflectivity values.
  
      Note .obj files are 1-indexed. The tensors returned from this function
      are 0-indexed. OBJ spec reference: http://www.martinreddy.net/gfx/3d/OBJ.spec
  
      Example .obj file format:
      ::
          # this is a comment
          v 1.000000 -1.000000 -1.000000
          v 1.000000 -1.000000 1.000000
          v -1.000000 -1.000000 1.000000
          v -1.000000 -1.000000 -1.000000
          v 1.000000 1.000000 -1.000000
          vt 0.748573 0.750412
          vt 0.749279 0.501284
          vt 0.999110 0.501077
          vt 0.999455 0.750380
          vn 0.000000 0.000000 -1.000000
          vn -1.000000 -0.000000 -0.000000
          vn -0.000000 -0.000000 1.000000
          f 5/2/1 1/2/1 4/3/1
          f 5/1/1 4/3/1 2/4/1
  
      The first character of the line denotes the type of input:
      ::
          - v is a vertex
          - vt is the texture coordinate of one vertex
          - vn is the normal of one vertex
          - f is a face
  
      Faces are interpreted as follows:
      ::
          5/2/1 describes the first vertex of the first triangle
          - 5: index of vertex [1.000000 1.000000 -1.000000]
          - 2: index of texture coordinate [0.749279 0.501284]
          - 1: index of normal [0.000000 0.000000 -1.000000]
  
      If there are faces with more than 3 vertices
      they are subdivided into triangles. Polygonal faces are assumed to have
      vertices ordered counter-clockwise so the (right-handed) normal points
      out of the screen e.g. a proper rectangular face would be specified like this:
      ::
          0_________1
          |         |
          |         |
          3 ________2
  
      The face would be split into two triangles: (0, 2, 1) and (0, 3, 2),
      both of which are also oriented counter-clockwise and have normals
      pointing out of the screen.
  
      Args:
          f: A file-like object (with methods read, readline, tell, and seek),
             a pathlib path or a string containing a file name.
          load_textures: Boolean indicating whether material files are loaded
          create_texture_atlas: Bool, If True a per face texture map is created and
              a tensor `texture_atlas` is also returned in `aux`.
          texture_atlas_size: Int specifying the resolution of the texture map per face
              when `create_texture_atlas=True`. A (texture_size, texture_size, 3)
              map is created per face.
          texture_wrap: string, one of ["repeat", "clamp"]. This applies when computing
              the texture atlas.
              If `texture_mode="repeat"`, for uv values outside the range [0, 1] the integer part
              is ignored and a repeating pattern is formed.
              If `texture_mode="clamp"` the values are clamped to the range [0, 1].
              If None, then there is no transformation of the texture values.
          device: Device (as str or torch.device) on which to return the new tensors.
          path_manager: optionally a PathManager object to interpret paths.
  
      Returns:
          6-element tuple containing
  
          - **verts**: FloatTensor of shape (V, 3).
          - **faces**: NamedTuple with fields:
              - verts_idx: LongTensor of vertex indices, shape (F, 3).
              - normals_idx: (optional) LongTensor of normal indices, shape (F, 3).
              - textures_idx: (optional) LongTensor of texture indices, shape (F, 3).
                This can be used to index into verts_uvs.
              - materials_idx: (optional) List of indices indicating which
                material the texture is derived from for each face.
                If there is no material for a face, the index is -1.
                This can be used to retrieve the corresponding values
                in material_colors/texture_images after they have been
                converted to tensors or Materials/Textures data
                structures - see textures.py and materials.py for
                more info.
          - **aux**: NamedTuple with fields:
              - normals: FloatTensor of shape (N, 3)
              - verts_uvs: FloatTensor of shape (T, 2), giving the uv coordinate per
                vertex. If a vertex is shared between two faces, it can have
                a different uv value for each instance. Therefore it is
                possible that the number of verts_uvs is greater than
                num verts i.e. T > V.
                vertex.
              - material_colors: if `load_textures=True` and the material has associated
                properties this will be a dict of material names and properties of the form:
  
                .. code-block:: python
  
                    {
                        material_name_1:  {
                            "ambient_color": tensor of shape (1, 3),
                            "diffuse_color": tensor of shape (1, 3),
                            "specular_color": tensor of shape (1, 3),
                            "shininess": tensor of shape (1)
                        },
                        material_name_2: {},
                        ...
                    }
  
                If a material does not have any properties it will have an
                empty dict. If `load_textures=False`, `material_colors` will None.
  
              - texture_images: if `load_textures=True` and the material has a texture map,
                this will be a dict of the form:
  
                .. code-block:: python
  
                    {
                        material_name_1: (H, W, 3) image,
                        ...
                    }
                If `load_textures=False`, `texture_images` will None.
              - texture_atlas: if `load_textures=True` and `create_texture_atlas=True`,
                this will be a FloatTensor of the form: (F, texture_size, textures_size, 3)
                If the material does not have a texture map, then all faces
                will have a uniform white texture.  Otherwise `texture_atlas` will be
                None.
      """
      data_dir = "./"
      if isinstance(f, (str, bytes, Path)):
          # pyre-fixme[6]: For 1st argument expected `PathLike[Variable[AnyStr <:
          #  [str, bytes]]]` but got `Union[Path, bytes, str]`.
          data_dir = os.path.dirname(f)
      if path_manager is None:
          path_manager = PathManager()
      with _open_file(f, path_manager, "r") as f:
          return _load_obj(
              f,
              data_dir=data_dir,
              load_textures=load_textures,
              create_texture_atlas=create_texture_atlas,
              texture_atlas_size=texture_atlas_size,
              texture_wrap=texture_wrap,
              path_manager=path_manager,
              device=device,
          )
  
imports: import os
  import warnings
  from collections import namedtuple
  from pathlib import Path
  from typing import List, Optional
  import numpy
  import torch
  from iopath.common.file_io import PathManager
  from PIL import Image
  from pytorch3d.common.datatypes import Device
  from pytorch3d.io.mtl_io import load_mtl, make_mesh_texture_atlas
  from pytorch3d.io.utils import _check_faces_indices, _make_tensor, _open_file, PathOrStr
  from pytorch3d.renderer import TexturesAtlas, TexturesUV
  from pytorch3d.structures import join_meshes_as_batch, Meshes
  from .pluggable_formats import endswith, MeshFormatInterpreter
label_desc: Use image node_id 2 for calling a global function with example usage: load_obj(f, load_textures, create_texture_atlas, texture_atlas_size, texture_wrap, device, path_manager) and returns: _load_obj