File size: 5,523 Bytes
ad06aed
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
# 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 Jiale Xu
# 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):
        """
        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)
        """

        dtype = cam2world_matrix.dtype
        device = cam2world_matrix.device
        N, M = cam2world_matrix.shape[0], render_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=dtype, device=device),
            torch.arange(render_size, dtype=dtype, device=device),
            indexing='ij',
        ))
        uv = uv.flip(0).reshape(2, -1).transpose(1, 0)
        uv = uv.unsqueeze(0).repeat(cam2world_matrix.shape[0], 1, 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), dtype=dtype, device=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).to(dtype)

        _opencv2blender = torch.tensor([
            [1, 0, 0, 0],
            [0, -1, 0, 0],
            [0, 0, -1, 0],
            [0, 0, 0, 1],
        ], dtype=dtype, device=device).unsqueeze(0).repeat(N, 1, 1)

        cam2world_matrix = torch.bmm(cam2world_matrix, _opencv2blender)

        world_rel_points = torch.bmm(cam2world_matrix, 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).to(dtype)

        ray_origins = cam_locs_world.unsqueeze(1).repeat(1, ray_dirs.shape[1], 1)

        return ray_origins, ray_dirs


class OrthoRaySampler(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, ortho_scale, render_size):
        """
        Create batches of rays and return origins and directions.

        cam2world_matrix: (N, 4, 4)
        ortho_scale: float
        render_size: int

        ray_origins: (N, M, 3)
        ray_dirs: (N, M, 3)
        """

        N, M = cam2world_matrix.shape[0], render_size**2

        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',
        ))
        uv = uv.flip(0).reshape(2, -1).transpose(1, 0)
        uv = uv.unsqueeze(0).repeat(cam2world_matrix.shape[0], 1, 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.zeros((N, M), device=cam2world_matrix.device)

        x_lift = (x_cam - 0.5) * ortho_scale
        y_lift = (y_cam - 0.5) * ortho_scale

        cam_rel_points = torch.stack((x_lift, y_lift, z_cam, torch.ones_like(z_cam)), dim=-1)

        _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)

        cam2world_matrix = torch.bmm(cam2world_matrix, _opencv2blender)

        ray_origins = torch.bmm(cam2world_matrix, cam_rel_points.permute(0, 2, 1)).permute(0, 2, 1)[:, :, :3]

        ray_dirs_cam = torch.stack([
            torch.zeros((N, M), device=cam2world_matrix.device),
            torch.zeros((N, M), device=cam2world_matrix.device),
            torch.ones((N, M), device=cam2world_matrix.device),
        ], dim=-1)
        ray_dirs = torch.bmm(cam2world_matrix[:, :3, :3], ray_dirs_cam.permute(0, 2, 1)).permute(0, 2, 1)

        return ray_origins, ray_dirs