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import torch
import numpy as np
from plyfile import PlyData, PlyElement
from .general_utils import inverse_sigmoid, strip_symmetric, build_scaling_rotation
class Gaussian:
def __init__(
self,
aabb : list,
sh_degree : int = 0,
mininum_kernel_size : float = 0.0,
scaling_bias : float = 0.01,
opacity_bias : float = 0.1,
scaling_activation : str = "exp",
device='cuda'
):
self.init_params = {
'aabb': aabb,
'sh_degree': sh_degree,
'mininum_kernel_size': mininum_kernel_size,
'scaling_bias': scaling_bias,
'opacity_bias': opacity_bias,
'scaling_activation': scaling_activation,
}
self.sh_degree = sh_degree
self.active_sh_degree = sh_degree
self.mininum_kernel_size = mininum_kernel_size
self.scaling_bias = scaling_bias
self.opacity_bias = opacity_bias
self.scaling_activation_type = scaling_activation
self.device = device
self.aabb = torch.tensor(aabb, dtype=torch.float32, device=device)
self.setup_functions()
self._xyz = None
self._features_dc = None
self._features_rest = None
self._scaling = None
self._rotation = None
self._opacity = None
def setup_functions(self):
def build_covariance_from_scaling_rotation(scaling, scaling_modifier, rotation):
L = build_scaling_rotation(scaling_modifier * scaling, rotation)
actual_covariance = L @ L.transpose(1, 2)
symm = strip_symmetric(actual_covariance)
return symm
if self.scaling_activation_type == "exp":
self.scaling_activation = torch.exp
self.inverse_scaling_activation = torch.log
elif self.scaling_activation_type == "softplus":
self.scaling_activation = torch.nn.functional.softplus
self.inverse_scaling_activation = lambda x: x + torch.log(-torch.expm1(-x))
self.covariance_activation = build_covariance_from_scaling_rotation
self.opacity_activation = torch.sigmoid
self.inverse_opacity_activation = inverse_sigmoid
self.rotation_activation = torch.nn.functional.normalize
self.scale_bias = self.inverse_scaling_activation(torch.tensor(self.scaling_bias)).cuda()
self.rots_bias = torch.zeros((4)).cuda()
self.rots_bias[0] = 1
self.opacity_bias = self.inverse_opacity_activation(torch.tensor(self.opacity_bias)).cuda()
@property
def get_scaling(self):
scales = self.scaling_activation(self._scaling + self.scale_bias)
scales = torch.square(scales) + self.mininum_kernel_size ** 2
scales = torch.sqrt(scales)
return scales
@property
def get_rotation(self):
return self.rotation_activation(self._rotation + self.rots_bias[None, :])
@property
def get_xyz(self):
return self._xyz * self.aabb[None, 3:] + self.aabb[None, :3]
@property
def get_features(self):
return torch.cat((self._features_dc, self._features_rest), dim=2) if self._features_rest is not None else self._features_dc
@property
def get_opacity(self):
return self.opacity_activation(self._opacity + self.opacity_bias)
def get_covariance(self, scaling_modifier = 1):
return self.covariance_activation(self.get_scaling, scaling_modifier, self._rotation + self.rots_bias[None, :])
def from_scaling(self, scales):
scales = torch.sqrt(torch.square(scales) - self.mininum_kernel_size ** 2)
self._scaling = self.inverse_scaling_activation(scales) - self.scale_bias
def from_rotation(self, rots):
self._rotation = rots - self.rots_bias[None, :]
def from_xyz(self, xyz):
self._xyz = (xyz - self.aabb[None, :3]) / self.aabb[None, 3:]
def from_features(self, features):
self._features_dc = features
def from_opacity(self, opacities):
self._opacity = self.inverse_opacity_activation(opacities) - self.opacity_bias
def construct_list_of_attributes(self):
l = ['x', 'y', 'z', 'nx', 'ny', 'nz']
# All channels except the 3 DC
for i in range(self._features_dc.shape[1]*self._features_dc.shape[2]):
l.append('f_dc_{}'.format(i))
l.append('opacity')
for i in range(self._scaling.shape[1]):
l.append('scale_{}'.format(i))
for i in range(self._rotation.shape[1]):
l.append('rot_{}'.format(i))
return l
def save_ply(self, path):
xyz = self.get_xyz.detach().cpu().numpy()
normals = np.zeros_like(xyz)
f_dc = self._features_dc.detach().transpose(1, 2).flatten(start_dim=1).contiguous().cpu().numpy()
opacities = inverse_sigmoid(self.get_opacity).detach().cpu().numpy()
scale = torch.log(self.get_scaling).detach().cpu().numpy()
rotation = (self._rotation + self.rots_bias[None, :]).detach().cpu().numpy()
dtype_full = [(attribute, 'f4') for attribute in self.construct_list_of_attributes()]
elements = np.empty(xyz.shape[0], dtype=dtype_full)
attributes = np.concatenate((xyz, normals, f_dc, opacities, scale, rotation), axis=1)
elements[:] = list(map(tuple, attributes))
el = PlyElement.describe(elements, 'vertex')
PlyData([el]).write(path)
def load_ply(self, path):
plydata = PlyData.read(path)
xyz = np.stack((np.asarray(plydata.elements[0]["x"]),
np.asarray(plydata.elements[0]["y"]),
np.asarray(plydata.elements[0]["z"])), axis=1)
opacities = np.asarray(plydata.elements[0]["opacity"])[..., np.newaxis]
features_dc = np.zeros((xyz.shape[0], 3, 1))
features_dc[:, 0, 0] = np.asarray(plydata.elements[0]["f_dc_0"])
features_dc[:, 1, 0] = np.asarray(plydata.elements[0]["f_dc_1"])
features_dc[:, 2, 0] = np.asarray(plydata.elements[0]["f_dc_2"])
if self.sh_degree > 0:
extra_f_names = [p.name for p in plydata.elements[0].properties if p.name.startswith("f_rest_")]
extra_f_names = sorted(extra_f_names, key = lambda x: int(x.split('_')[-1]))
assert len(extra_f_names)==3*(self.sh_degree + 1) ** 2 - 3
features_extra = np.zeros((xyz.shape[0], len(extra_f_names)))
for idx, attr_name in enumerate(extra_f_names):
features_extra[:, idx] = np.asarray(plydata.elements[0][attr_name])
# Reshape (P,F*SH_coeffs) to (P, F, SH_coeffs except DC)
features_extra = features_extra.reshape((features_extra.shape[0], 3, (self.max_sh_degree + 1) ** 2 - 1))
scale_names = [p.name for p in plydata.elements[0].properties if p.name.startswith("scale_")]
scale_names = sorted(scale_names, key = lambda x: int(x.split('_')[-1]))
scales = np.zeros((xyz.shape[0], len(scale_names)))
for idx, attr_name in enumerate(scale_names):
scales[:, idx] = np.asarray(plydata.elements[0][attr_name])
rot_names = [p.name for p in plydata.elements[0].properties if p.name.startswith("rot")]
rot_names = sorted(rot_names, key = lambda x: int(x.split('_')[-1]))
rots = np.zeros((xyz.shape[0], len(rot_names)))
for idx, attr_name in enumerate(rot_names):
rots[:, idx] = np.asarray(plydata.elements[0][attr_name])
# convert to actual gaussian attributes
xyz = torch.tensor(xyz, dtype=torch.float, device=self.device)
features_dc = torch.tensor(features_dc, dtype=torch.float, device=self.device).transpose(1, 2).contiguous()
if self.sh_degree > 0:
features_extra = torch.tensor(features_extra, dtype=torch.float, device=self.device).transpose(1, 2).contiguous()
opacities = torch.sigmoid(torch.tensor(opacities, dtype=torch.float, device=self.device))
scales = torch.exp(torch.tensor(scales, dtype=torch.float, device=self.device))
rots = torch.tensor(rots, dtype=torch.float, device=self.device)
# convert to _hidden attributes
self._xyz = (xyz - self.aabb[None, :3]) / self.aabb[None, 3:]
self._features_dc = features_dc
if self.sh_degree > 0:
self._features_rest = features_extra
else:
self._features_rest = None
self._opacity = self.inverse_opacity_activation(opacities) - self.opacity_bias
self._scaling = self.inverse_scaling_activation(torch.sqrt(torch.square(scales) - self.mininum_kernel_size ** 2)) - self.scale_bias
self._rotation = rots - self.rots_bias[None, :]