import numpy as np
from numpy import ndarray


def transform_coordinates_3d(coordinates: ndarray, sRT: ndarray):
    assert coordinates.shape[0] == 3
    coordinates = np.vstack(
        [coordinates, np.ones((1, coordinates.shape[1]), dtype=np.float32)]
    )
    new_coordinates = sRT @ coordinates
    new_coordinates = new_coordinates[:3, :] / new_coordinates[3, :]
    return new_coordinates