def _load_materials(material_names: List[str], f, data_dir: str, *,
load_textures: bool, device):
"""
Load materials and optionally textures from the specified path.
Args:
material_names: a list of the material names found in the .obj file.
f: a file-like object of the material information.
data_dir: the directory where the material texture files are located.
load_textures: whether textures should be loaded.
device: string or torch.device on which to return the new tensors.
Returns:
material_colors: dict of properties for each material.
texture_images: dict of material names and texture images.
"""
if not load_textures:
return None, None
if not material_names or f is None:
if material_names:
warnings.warn("No mtl file provided")
return None, None
if not os.path.isfile(f):
warnings.warn(f"Mtl file does not exist: {f}")
return None, None
# Texture mode uv wrap
return load_mtl(f, material_names, data_dir, device=device)
def _load_materials(
material_names: List[str],
f: Optional[str],
*,
data_dir: str,
load_textures: bool,
device: Device,
path_manager: PathManager,
):
"""
Load materials and optionally textures from the specified path.
Args:
material_names: a list of the material names found in the .obj file.
f: path to the material information.
data_dir: the directory where the material texture files are located.
load_textures: whether textures should be loaded.
device: Device (as str or torch.device) on which to return the new tensors.
path_manager: PathManager object to interpret paths.
Returns:
material_colors: dict of properties for each material.
texture_images: dict of material names and texture images.
"""
if not load_textures:
return None, None
if not material_names or f is None:
if material_names:
warnings.warn("No mtl file provided")
return None, None
if not path_manager.exists(f):
warnings.warn(f"Mtl file does not exist: {f}")
return None, None
# Texture mode uv wrap
return load_mtl(
f,
material_names=material_names,
data_dir=data_dir,
path_manager=path_manager,
device=device,
)
def _load_obj(
f_obj,
data_dir,
load_textures: bool = True,
create_texture_atlas: bool = False,
texture_atlas_size: int = 4,
texture_wrap: Optional[str] = "repeat",
device="cpu",
):
"""
Load a mesh from a file-like object. See load_obj function more details.
Any material files associated with the obj are expected to be in the
directory given by data_dir.
"""
if texture_wrap is not None and texture_wrap not in ["repeat", "clamp"]:
msg = "texture_wrap must be one of ['repeat', 'clamp'] or None, got %s"
raise ValueError(msg % texture_wrap)
lines = [line.strip() for line in f_obj]
verts = []
normals = []
verts_uvs = []
faces_verts_idx = []
faces_normals_idx = []
faces_textures_idx = []
material_names = []
faces_materials_idx = []
f_mtl = None
materials_idx = -1
# startswith expects each line to be a string. If the file is read in as
# bytes then first decode to strings.
if lines and isinstance(lines[0], bytes):
lines = [el.decode("utf-8") for el in lines]
for line in lines:
if line.startswith("mtllib"):
if len(line.split()) < 2:
raise ValueError("material file name is not specified")
# NOTE: only allow one .mtl file per .obj.
# Definitions for multiple materials can be included
# in this one .mtl file.
f_mtl = os.path.join(data_dir, line.split()[1])
elif len(line.split()) != 0 and line.split()[0] == "usemtl":
material_name = line.split()[1]
# materials are often repeated for different parts
# of a mesh.
if material_name not in material_names:
material_names.append(material_name)
materials_idx = len(material_names) - 1
else:
materials_idx = material_names.index(material_name)
elif line.startswith("v "):
# Line is a vertex.
vert = [float(x) for x in line.split()[1:4]]
if len(vert) != 3:
msg = "Vertex %s does not have 3 values. Line: %s"
raise ValueError(msg % (str(vert), str(line)))
verts.append(vert)
elif line.startswith("vt "):
# Line is a texture.
tx = [float(x) for x in line.split()[1:3]]
if len(tx) != 2:
raise ValueError(
"Texture %s does not have 2 values. Line: %s" % (str(tx), str(line))
)
verts_uvs.append(tx)
elif line.startswith("vn "):
# Line is a normal.
norm = [float(x) for x in line.split()[1:4]]
if len(norm) != 3:
msg = "Normal %s does not have 3 values. Line: %s"
raise ValueError(msg % (str(norm), str(line)))
normals.append(norm)
elif line.startswith("f "):
# Line is a face update face properties info.
_parse_face(
line,
materials_idx,
faces_verts_idx,
faces_normals_idx,
faces_textures_idx,
faces_materials_idx,
)
verts = _make_tensor(verts, cols=3, dtype=torch.float32, device=device) # (V, 3)
normals = _make_tensor(
normals, cols=3, dtype=torch.float32, device=device
) # (N, 3)
verts_uvs = _make_tensor(
verts_uvs, cols=2, dtype=torch.float32, device=device
) # (T, 2)
faces_verts_idx = _format_faces_indices(
faces_verts_idx, verts.shape[0], device=device
)
# Repeat for normals and textures if present.
if len(faces_normals_idx) > 0:
faces_normals_idx = _format_faces_indices(
faces_normals_idx, normals.shape[0], device=device, pad_value=-1
)
if len(faces_textures_idx) > 0:
faces_textures_idx = _format_faces_indices(
faces_textures_idx, verts_uvs.shape[0], device=device, pad_value=-1
)
if len(faces_materials_idx) > 0:
faces_materials_idx = torch.tensor(
faces_materials_idx, dtype=torch.int64, device=device
)
# Load materials
material_colors, texture_images, texture_atlas = None, None, None
if load_textures:
if (len(material_names) > 0) and (f_mtl is not None):
# pyre-fixme[6]: Expected `Union[_PathLike[typing.Any], bytes, str]` for
# 1st param but got `Optional[str]`.
if os.path.isfile(f_mtl):
# Texture mode uv wrap
material_colors, texture_images = load_mtl(
f_mtl, material_names, data_dir, device=device
)
if create_texture_atlas:
# Using the images and properties from the
# material file make a per face texture map.
# Create an array of strings of material names for each face.
# If faces_materials_idx == -1 then that face doesn't have a material.
idx = faces_materials_idx.cpu().numpy()
face_material_names = np.array(material_names)[idx] # (F,)
face_material_names[idx == -1] = ""
# Get the uv coords for each vert in each face
faces_verts_uvs = verts_uvs[faces_textures_idx] # (F, 3, 2)
# Construct the atlas.
texture_atlas = make_mesh_texture_atlas(
material_colors,
texture_images,
face_material_names,
faces_verts_uvs,
texture_atlas_size,
texture_wrap,
)
else:
warnings.warn(f"Mtl file does not exist: {f_mtl}")
elif len(material_names) > 0:
warnings.warn("No mtl file provided")
faces = _Faces(
verts_idx=faces_verts_idx,
normals_idx=faces_normals_idx,
textures_idx=faces_textures_idx,
materials_idx=faces_materials_idx,
)
aux = _Aux(
normals=normals if len(normals) > 0 else None,
verts_uvs=verts_uvs if len(verts_uvs) > 0 else None,
material_colors=material_colors,
texture_images=texture_images,
texture_atlas=texture_atlas,
)
return verts, faces, aux