def _load_texture_images(
material_names: List[str],
data_dir: str,
material_properties: MaterialProperties,
texture_files: TextureFiles,
) -> Tuple[MaterialProperties, TextureImages]:
final_material_properties = {}
texture_images = {}
# Only keep the materials referenced in the obj.
for material_name in material_names:
if material_name in texture_files:
# Load the texture image.
path = os.path.join(data_dir, texture_files[material_name])
if os.path.isfile(path):
image = _read_image(path, format="RGB") / 255.0
image = torch.from_numpy(image)
texture_images[material_name] = image
else:
msg = f"Texture file does not exist: {path}"
warnings.warn(msg)
if material_name in material_properties:
final_material_properties[material_name] = material_properties[
material_name]
return final_material_properties, texture_images
def _load_texture_images(
material_names: List[str],
data_dir: str,
material_properties: MaterialProperties,
texture_files: TextureFiles,
path_manager: PathManager,
) -> Tuple[MaterialProperties, TextureImages]:
final_material_properties = {}
texture_images = {}
used_material_names = list(material_names)
if not used_material_names and material_properties:
if len(material_properties) > 1:
raise ValueError(
"Multiple materials but no usemtl declarations in the obj file"
)
# No materials were specified in obj file and only one is in the
# specified .mtl file, so we use it.
used_material_names.append(next(iter(material_properties.keys())))
# Only keep the materials referenced in the obj.
for material_name in used_material_names:
if material_name in texture_files:
# Load the texture image.
path = os.path.join(data_dir, texture_files[material_name])
if path_manager.exists(path):
image = (_read_image(
path, path_manager=path_manager, format="RGB") / 255.0)
image = torch.from_numpy(image)
texture_images[material_name] = image
else:
msg = f"Texture file does not exist: {path}"
warnings.warn(msg)
if material_name in material_properties:
final_material_properties[material_name] = material_properties[
material_name]
return final_material_properties, texture_images
def load_mtl(f_mtl, material_names: List, data_dir: str, device="cpu"):
"""
Load texture images and material reflectivity values for ambient, diffuse
and specular light (Ka, Kd, Ks, Ns).
Args:
f_mtl: a file like object of the material information.
material_names: a list of the material names found in the .obj file.
data_dir: the directory where the material texture files are located.
Returns:
material_colors: dict of properties for each material. If a material
does not have any properties it will have an emtpy dict.
{
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: {},
...
}
texture_images: dict of material names and texture images
{
material_name_1: (H, W, 3) image,
...
}
"""
texture_files = {}
material_colors = {}
material_properties = {}
texture_images = {}
material_name = ""
f_mtl, new_f = _open_file(f_mtl)
lines = [line.strip() for line in f_mtl]
for line in lines:
if len(line.split()) != 0:
if line.split()[0] == "newmtl":
material_name = line.split()[1]
material_colors[material_name] = {}
if line.split()[0] == "map_Kd":
# Texture map.
texture_files[material_name] = line.split()[1]
if line.split()[0] == "Kd":
# RGB diffuse reflectivity
kd = np.array(list(line.split()[1:4])).astype(np.float32)
kd = torch.from_numpy(kd).to(device)
material_colors[material_name]["diffuse_color"] = kd
if line.split()[0] == "Ka":
# RGB ambient reflectivity
ka = np.array(list(line.split()[1:4])).astype(np.float32)
ka = torch.from_numpy(ka).to(device)
material_colors[material_name]["ambient_color"] = ka
if line.split()[0] == "Ks":
# RGB specular reflectivity
ks = np.array(list(line.split()[1:4])).astype(np.float32)
ks = torch.from_numpy(ks).to(device)
material_colors[material_name]["specular_color"] = ks
if line.split()[0] == "Ns":
# Specular exponent
ns = np.array(list(line.split()[1:4])).astype(np.float32)
ns = torch.from_numpy(ns).to(device)
material_colors[material_name]["shininess"] = ns
if new_f:
f_mtl.close()
# Only keep the materials referenced in the obj.
for name in material_names:
if name in texture_files:
# Load the texture image.
filename = texture_files[name]
filename_texture = os.path.join(data_dir, filename)
if os.path.isfile(filename_texture):
image = _read_image(filename_texture, format="RGB") / 255.0
image = torch.from_numpy(image)
texture_images[name] = image
else:
msg = f"Texture file does not exist: {filename_texture}"
warnings.warn(msg)
if name in material_colors:
material_properties[name] = material_colors[name]
return material_properties, texture_images
