test_curvature.py

try:
    from . import generic as g
except BaseException:
    import generic as g


class CurvatureTest(g.unittest.TestCase):

    def test_gaussian_curvature(self):

        for radius in g.np.linspace(.25, 2.0, 10):
            m = g.trimesh.creation.icosphere(radius=radius)

            gauss = g.trimesh.curvature.discrete_gaussian_curvature_measure(
                mesh=m,
                points=m.vertices,
                radius=radius * 2.0) / (4 * g.np.pi)
            assert g.np.allclose(gauss, 1.0, atol=.01)

        # a torus should have approximately half its vertices with positive
        # curvature, and half with negative
        t = g.get_mesh('torus.STL')
        gauss = g.trimesh.curvature.discrete_gaussian_curvature_measure(
            mesh=t,
            points=t.vertices,
            radius=1.0)
        ratio = float((gauss < 0.0).sum()) / float(len(gauss))
        assert g.np.isclose(ratio, 0.5, atol=.2)

    def test_mean_curvature(self):
        m = g.trimesh.creation.icosphere()
        mean = g.trimesh.curvature.discrete_mean_curvature_measure(
            m,
            m.vertices,
            2.0) / (4 * g.np.pi)
        # Check mean curvature for unit sphere is 1.0
        assert g.np.allclose(mean, 1.0, atol=.01)

    def test_vertex_defect(self):
        # a subdivided box will only have corners and planar regions
        # so all vertex defects should be 0 or 90 degrees
        m = g.trimesh.primitives.Box().subdivide()
        assert g.np.logical_or(g.np.isclose(m.vertex_defects, 0.0),
                               g.np.isclose(m.vertex_defects, g.np.pi / 2.0)).all()

        assert len(m.vertex_defects) == len(m.vertices)


if __name__ == '__main__':
    g.trimesh.util.attach_to_log()
    g.unittest.main()