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import numpy as np | |
import torch | |
import torch.nn as nn | |
import torch.nn.functional as F | |
from diff_gaussian_rasterization import ( | |
GaussianRasterizationSettings, | |
GaussianRasterizer, | |
) | |
from core.options import Options | |
import kiui | |
class GaussianRenderer: | |
def __init__(self, opt: Options): | |
self.opt = opt | |
self.bg_color = torch.tensor([1, 1, 1], dtype=torch.float32, device="cuda") | |
# intrinsics | |
self.tan_half_fov = np.tan(0.5 * np.deg2rad(self.opt.fovy)) | |
self.proj_matrix = torch.zeros(4, 4, dtype=torch.float32) | |
self.proj_matrix[0, 0] = 1 / self.tan_half_fov | |
self.proj_matrix[1, 1] = 1 / self.tan_half_fov | |
self.proj_matrix[2, 2] = (opt.zfar + opt.znear) / (opt.zfar - opt.znear) | |
self.proj_matrix[3, 2] = - (opt.zfar * opt.znear) / (opt.zfar - opt.znear) | |
self.proj_matrix[2, 3] = 1 | |
def render(self, gaussians, cam_view, cam_view_proj, cam_pos, bg_color=None, scale_modifier=1): | |
# gaussians: [B, N, 14] | |
# cam_view, cam_view_proj: [B, V, 4, 4] | |
# cam_pos: [B, V, 3] | |
device = gaussians.device | |
B, V = cam_view.shape[:2] | |
# loop of loop... | |
images = [] | |
alphas = [] | |
for b in range(B): | |
# pos, opacity, scale, rotation, shs | |
means3D = gaussians[b, :, 0:3].contiguous().float() | |
opacity = gaussians[b, :, 3:4].contiguous().float() | |
scales = gaussians[b, :, 4:7].contiguous().float() | |
rotations = gaussians[b, :, 7:11].contiguous().float() | |
rgbs = gaussians[b, :, 11:].contiguous().float() # [N, 3] | |
for v in range(V): | |
# render novel views | |
view_matrix = cam_view[b, v].float() | |
view_proj_matrix = cam_view_proj[b, v].float() | |
campos = cam_pos[b, v].float() | |
raster_settings = GaussianRasterizationSettings( | |
image_height=self.opt.output_size, | |
image_width=self.opt.output_size, | |
tanfovx=self.tan_half_fov, | |
tanfovy=self.tan_half_fov, | |
bg=self.bg_color if bg_color is None else bg_color, | |
scale_modifier=scale_modifier, | |
viewmatrix=view_matrix, | |
projmatrix=view_proj_matrix, | |
sh_degree=0, | |
campos=campos, | |
prefiltered=False, | |
debug=False, | |
) | |
rasterizer = GaussianRasterizer(raster_settings=raster_settings) | |
# Rasterize visible Gaussians to image, obtain their radii (on screen). | |
rendered_image, radii, rendered_depth, rendered_alpha = rasterizer( | |
means3D=means3D, | |
means2D=torch.zeros_like(means3D, dtype=torch.float32, device=device), | |
shs=None, | |
colors_precomp=rgbs, | |
opacities=opacity, | |
scales=scales, | |
rotations=rotations, | |
cov3D_precomp=None, | |
) | |
rendered_image = rendered_image.clamp(0, 1) | |
images.append(rendered_image) | |
alphas.append(rendered_alpha) | |
images = torch.stack(images, dim=0).view(B, V, 3, self.opt.output_size, self.opt.output_size) | |
alphas = torch.stack(alphas, dim=0).view(B, V, 1, self.opt.output_size, self.opt.output_size) | |
return { | |
"image": images, # [B, V, 3, H, W] | |
"alpha": alphas, # [B, V, 1, H, W] | |
} | |
def save_ply(self, gaussians, path, compatible=True): | |
# gaussians: [B, N, 14] | |
# compatible: save pre-activated gaussians as in the original paper | |
assert gaussians.shape[0] == 1, 'only support batch size 1' | |
from plyfile import PlyData, PlyElement | |
means3D = gaussians[0, :, 0:3].contiguous().float() | |
opacity = gaussians[0, :, 3:4].contiguous().float() | |
scales = gaussians[0, :, 4:7].contiguous().float() | |
rotations = gaussians[0, :, 7:11].contiguous().float() | |
shs = gaussians[0, :, 11:].unsqueeze(1).contiguous().float() # [N, 1, 3] | |
# prune by opacity | |
mask = opacity.squeeze(-1) >= 0.005 | |
means3D = means3D[mask] | |
opacity = opacity[mask] | |
scales = scales[mask] | |
rotations = rotations[mask] | |
shs = shs[mask] | |
# invert activation to make it compatible with the original ply format | |
if compatible: | |
opacity = kiui.op.inverse_sigmoid(opacity) | |
scales = torch.log(scales + 1e-8) | |
shs = (shs - 0.5) / 0.28209479177387814 | |
xyzs = means3D.detach().cpu().numpy() | |
f_dc = shs.detach().transpose(1, 2).flatten(start_dim=1).contiguous().cpu().numpy() | |
opacities = opacity.detach().cpu().numpy() | |
scales = scales.detach().cpu().numpy() | |
rotations = rotations.detach().cpu().numpy() | |
l = ['x', 'y', 'z'] | |
# All channels except the 3 DC | |
for i in range(f_dc.shape[1]): | |
l.append('f_dc_{}'.format(i)) | |
l.append('opacity') | |
for i in range(scales.shape[1]): | |
l.append('scale_{}'.format(i)) | |
for i in range(rotations.shape[1]): | |
l.append('rot_{}'.format(i)) | |
dtype_full = [(attribute, 'f4') for attribute in l] | |
elements = np.empty(xyzs.shape[0], dtype=dtype_full) | |
attributes = np.concatenate((xyzs, f_dc, opacities, scales, rotations), axis=1) | |
elements[:] = list(map(tuple, attributes)) | |
el = PlyElement.describe(elements, 'vertex') | |
PlyData([el]).write(path) | |
def load_ply(self, path, compatible=True): | |
from plyfile import PlyData, PlyElement | |
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) | |
print("Number of points at loading : ", xyz.shape[0]) | |
opacities = np.asarray(plydata.elements[0]["opacity"])[..., np.newaxis] | |
shs = np.zeros((xyz.shape[0], 3)) | |
shs[:, 0] = np.asarray(plydata.elements[0]["f_dc_0"]) | |
shs[:, 1] = np.asarray(plydata.elements[0]["f_dc_1"]) | |
shs[:, 2] = np.asarray(plydata.elements[0]["f_dc_2"]) | |
scale_names = [p.name for p in plydata.elements[0].properties if p.name.startswith("scale_")] | |
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_")] | |
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]) | |
gaussians = np.concatenate([xyz, opacities, scales, rots, shs], axis=1) | |
gaussians = torch.from_numpy(gaussians).float() # cpu | |
if compatible: | |
gaussians[..., 3:4] = torch.sigmoid(gaussians[..., 3:4]) | |
gaussians[..., 4:7] = torch.exp(gaussians[..., 4:7]) | |
gaussians[..., 11:] = 0.28209479177387814 * gaussians[..., 11:] + 0.5 | |
return gaussians |