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# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
# SPDX-FileCopyrightText: Copyright (c) 2021-2022 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: LicenseRef-NvidiaProprietary
#
# NVIDIA CORPORATION, its affiliates and licensors retain all intellectual
# property and proprietary rights in and to this material, related
# documentation and any modifications thereto. Any use, reproduction,
# disclosure or distribution of this material and related documentation
# without an express license agreement from NVIDIA CORPORATION or
# its affiliates is strictly prohibited.
#
# Modified by Zexin He
# The modifications are subject to the same license as the original.
"""
The ray sampler is a module that takes in camera matrices and resolution and batches of rays.
Expects cam2world matrices that use the OpenCV camera coordinate system conventions.
"""
import torch
class RaySampler(torch.nn.Module):
def __init__(self):
super().__init__()
self.ray_origins_h, self.ray_directions, self.depths, self.image_coords, self.rendering_options = None, None, None, None, None
def forward(self, cam2world_matrix, intrinsics, render_size, crop_size, start_x, start_y):
"""
Create batches of rays and return origins and directions.
cam2world_matrix: (N, 4, 4)
intrinsics: (N, 3, 3)
render_size: int
ray_origins: (N, M, 3)
ray_dirs: (N, M, 2)
"""
N, M = cam2world_matrix.shape[0], crop_size**2
cam_locs_world = cam2world_matrix[:, :3, 3]
fx = intrinsics[:, 0, 0]
fy = intrinsics[:, 1, 1]
cx = intrinsics[:, 0, 2]
cy = intrinsics[:, 1, 2]
sk = intrinsics[:, 0, 1]
uv = torch.stack(torch.meshgrid(
torch.arange(render_size, dtype=torch.float32, device=cam2world_matrix.device),
torch.arange(render_size, dtype=torch.float32, device=cam2world_matrix.device),
indexing='ij',
))
if crop_size < render_size:
patch_uv = []
for i in range(cam2world_matrix.shape[0]):
patch_uv.append(uv.clone()[None, :, start_y:start_y+crop_size, start_x:start_x+crop_size])
uv = torch.cat(patch_uv, 0)
uv = uv.flip(1).reshape(cam2world_matrix.shape[0], 2, -1).transpose(2, 1)
else:
uv = uv.flip(0).reshape(2, -1).transpose(1, 0)
uv = uv.unsqueeze(0).repeat(cam2world_matrix.shape[0], 1, 1)
# uv = uv.unsqueeze(0).repeat(cam2world_matrix.shape[0], 1, 1)
# uv = uv.flip(1).reshape(cam2world_matrix.shape[0], 2, -1).transpose(2, 1)
x_cam = uv[:, :, 0].view(N, -1) * (1./render_size) + (0.5/render_size)
y_cam = uv[:, :, 1].view(N, -1) * (1./render_size) + (0.5/render_size)
z_cam = torch.ones((N, M), device=cam2world_matrix.device)
x_lift = (x_cam - cx.unsqueeze(-1) + cy.unsqueeze(-1)*sk.unsqueeze(-1)/fy.unsqueeze(-1) - sk.unsqueeze(-1)*y_cam/fy.unsqueeze(-1)) / fx.unsqueeze(-1) * z_cam
y_lift = (y_cam - cy.unsqueeze(-1)) / fy.unsqueeze(-1) * z_cam
cam_rel_points = torch.stack((x_lift, y_lift, z_cam, torch.ones_like(z_cam)), dim=-1).float()
_opencv2blender = torch.tensor([
[1, 0, 0, 0],
[0, -1, 0, 0],
[0, 0, -1, 0],
[0, 0, 0, 1],
], dtype=torch.float32, device=cam2world_matrix.device).unsqueeze(0).repeat(N, 1, 1)
# added float here
cam2world_matrix = torch.bmm(cam2world_matrix.float(), _opencv2blender.float())
world_rel_points = torch.bmm(cam2world_matrix.float(), cam_rel_points.permute(0, 2, 1)).permute(0, 2, 1)[:, :, :3]
ray_dirs = world_rel_points - cam_locs_world[:, None, :]
ray_dirs = torch.nn.functional.normalize(ray_dirs, dim=2)
ray_origins = cam_locs_world.unsqueeze(1).repeat(1, ray_dirs.shape[1], 1)
return ray_origins, ray_dirs |