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# Copyright (c) Meta Platforms, Inc. and affiliates. | |
# All rights reserved. | |
# | |
# This source code is licensed under the BSD-style license found in the | |
# LICENSE file in the root directory of this source tree. | |
import unittest | |
from math import radians | |
import torch | |
from pytorch3d.renderer.camera_utils import camera_to_eye_at_up, rotate_on_spot | |
from pytorch3d.renderer.cameras import ( | |
get_world_to_view_transform, | |
look_at_view_transform, | |
PerspectiveCameras, | |
) | |
from pytorch3d.transforms import axis_angle_to_matrix | |
from torch.nn.functional import normalize | |
from .common_testing import TestCaseMixin | |
def _batched_dotprod(x: torch.Tensor, y: torch.Tensor): | |
""" | |
Takes two tensors of shape (N,3) and returns their batched | |
dot product along the last dimension as a tensor of shape | |
(N,). | |
""" | |
return torch.einsum("ij,ij->i", x, y) | |
class TestCameraUtils(TestCaseMixin, unittest.TestCase): | |
def setUp(self) -> None: | |
torch.manual_seed(42) | |
def test_invert_eye_at_up(self): | |
# Generate random cameras and check we can reconstruct their eye, at, | |
# and up vectors. | |
N = 13 | |
eye = torch.rand(N, 3) | |
at = torch.rand(N, 3) | |
up = torch.rand(N, 3) | |
R, T = look_at_view_transform(eye=eye, at=at, up=up) | |
cameras = PerspectiveCameras(R=R, T=T) | |
eye2, at2, up2 = camera_to_eye_at_up(cameras.get_world_to_view_transform()) | |
# The retrieved eye matches | |
self.assertClose(eye, eye2, atol=1e-5) | |
self.assertClose(cameras.get_camera_center(), eye) | |
# at-eye as retrieved must be a vector in the same direction as | |
# the original. | |
self.assertClose(normalize(at - eye), normalize(at2 - eye2)) | |
# The up vector as retrieved should be rotated the same amount | |
# around at-eye as the original. The component in the at-eye | |
# direction is unimportant, as is the length. | |
# So check that (up x (at-eye)) as retrieved is in the same | |
# direction as its original value. | |
up_check = torch.cross(up, at - eye, dim=-1) | |
up_check2 = torch.cross(up2, at - eye, dim=-1) | |
self.assertClose(normalize(up_check), normalize(up_check2)) | |
# Master check that we get the same camera if we reinitialise. | |
R2, T2 = look_at_view_transform(eye=eye2, at=at2, up=up2) | |
cameras2 = PerspectiveCameras(R=R2, T=T2) | |
cam_trans = cameras.get_world_to_view_transform() | |
cam_trans2 = cameras2.get_world_to_view_transform() | |
self.assertClose(cam_trans.get_matrix(), cam_trans2.get_matrix(), atol=1e-5) | |
def test_rotate_on_spot_yaw(self): | |
N = 14 | |
eye = torch.rand(N, 3) | |
at = torch.rand(N, 3) | |
up = torch.rand(N, 3) | |
R, T = look_at_view_transform(eye=eye, at=at, up=up) | |
# Moving around the y axis looks left. | |
angles = torch.FloatTensor([0, -radians(10), 0]) | |
rotation = axis_angle_to_matrix(angles) | |
R_rot, T_rot = rotate_on_spot(R, T, rotation) | |
eye_rot, at_rot, up_rot = camera_to_eye_at_up( | |
get_world_to_view_transform(R=R_rot, T=T_rot) | |
) | |
self.assertClose(eye, eye_rot, atol=1e-5) | |
# Make vectors pointing exactly left and up | |
left = torch.cross(up, at - eye, dim=-1) | |
left_rot = torch.cross(up_rot, at_rot - eye_rot, dim=-1) | |
fully_up = torch.cross(at - eye, left, dim=-1) | |
fully_up_rot = torch.cross(at_rot - eye_rot, left_rot, dim=-1) | |
# The up direction is unchanged | |
self.assertClose(normalize(fully_up), normalize(fully_up_rot), atol=1e-5) | |
# The camera has moved left | |
agree = _batched_dotprod(torch.cross(left, left_rot, dim=1), fully_up) | |
self.assertGreater(agree.min(), 0) | |
# Batch dimension for rotation | |
R_rot2, T_rot2 = rotate_on_spot(R, T, rotation.expand(N, 3, 3)) | |
self.assertClose(R_rot, R_rot2) | |
self.assertClose(T_rot, T_rot2) | |
# No batch dimension for either | |
R_rot3, T_rot3 = rotate_on_spot(R[0], T[0], rotation) | |
self.assertClose(R_rot[:1], R_rot3) | |
self.assertClose(T_rot[:1], T_rot3) | |
# No batch dimension for R, T | |
R_rot4, T_rot4 = rotate_on_spot(R[0], T[0], rotation.expand(N, 3, 3)) | |
self.assertClose(R_rot[:1].expand(N, 3, 3), R_rot4) | |
self.assertClose(T_rot[:1].expand(N, 3), T_rot4) | |
def test_rotate_on_spot_pitch(self): | |
N = 14 | |
eye = torch.rand(N, 3) | |
at = torch.rand(N, 3) | |
up = torch.rand(N, 3) | |
R, T = look_at_view_transform(eye=eye, at=at, up=up) | |
# Moving around the x axis looks down. | |
angles = torch.FloatTensor([-radians(10), 0, 0]) | |
rotation = axis_angle_to_matrix(angles) | |
R_rot, T_rot = rotate_on_spot(R, T, rotation) | |
eye_rot, at_rot, up_rot = camera_to_eye_at_up( | |
get_world_to_view_transform(R=R_rot, T=T_rot) | |
) | |
self.assertClose(eye, eye_rot, atol=1e-5) | |
# A vector pointing left is unchanged | |
left = torch.cross(up, at - eye, dim=-1) | |
left_rot = torch.cross(up_rot, at_rot - eye_rot, dim=-1) | |
self.assertClose(normalize(left), normalize(left_rot), atol=1e-5) | |
# The camera has moved down | |
fully_up = torch.cross(at - eye, left, dim=-1) | |
fully_up_rot = torch.cross(at_rot - eye_rot, left_rot, dim=-1) | |
agree = _batched_dotprod(torch.cross(fully_up, fully_up_rot, dim=1), left) | |
self.assertGreater(agree.min(), 0) | |
def test_rotate_on_spot_roll(self): | |
N = 14 | |
eye = torch.rand(N, 3) | |
at = torch.rand(N, 3) | |
up = torch.rand(N, 3) | |
R, T = look_at_view_transform(eye=eye, at=at, up=up) | |
# Moving around the z axis rotates the image. | |
angles = torch.FloatTensor([0, 0, -radians(10)]) | |
rotation = axis_angle_to_matrix(angles) | |
R_rot, T_rot = rotate_on_spot(R, T, rotation) | |
eye_rot, at_rot, up_rot = camera_to_eye_at_up( | |
get_world_to_view_transform(R=R_rot, T=T_rot) | |
) | |
self.assertClose(eye, eye_rot, atol=1e-5) | |
self.assertClose(normalize(at - eye), normalize(at_rot - eye), atol=1e-5) | |
# The camera has moved clockwise | |
agree = _batched_dotprod(torch.cross(up, up_rot, dim=1), at - eye) | |
self.assertGreater(agree.min(), 0) | |