Function tangent_vectors

s3f/surface.py:404–412

(normals)

    

def tangent_vectors(normals):
    x, y, z = normals[..., 0], normals[..., 1], normals[..., 2]
    s = (2 * (z >= 0)) - 1.0  # = z.sign(), but =1. if z=0.
    a = -1 / (s + z)
    b = x * y * a
    uv = torch.stack((1 + s * x * x * a, s * b, -s * x, b, s + y * y * a, -y), dim=-1)
    uv = uv.view(uv.shape[:-1] + (2, 3))

    return uv


def curvatures(