def test_const_par_crv(self):
# more or less random 2D surface with p=[2,2] and n=[4,3]
controlpoints = [[0, 0], [-1, 1], [0, 2], [1, -1], [1, 0], [1, 1],
[2, 1], [2, 2], [2, 3], [3, 0], [4, 1], [3, 2]]
basis1 = BSplineBasis(3, [0, 0, 0, .4, 1, 1, 1])
basis2 = BSplineBasis(3, [0, 0, 0, 1, 1, 1])
surf = Surface(basis1, basis2, controlpoints)
surf.refine(1)
# try general knot in u-direction
crv = surf.const_par_curve(0.3, 'u')
v = np.linspace(0, 1, 13)
self.assertTrue(np.allclose(surf(0.3, v), crv(v)))
# try existing knot in u-direction
crv = surf.const_par_curve(0.4, 'u')
v = np.linspace(0, 1, 13)
self.assertTrue(np.allclose(surf(0.4, v), crv(v)))
# try general knot in v-direction
crv = surf.const_par_curve(0.3, 'v')
u = np.linspace(0, 1, 13)
self.assertTrue(np.allclose(surf(u, 0.3).reshape(13, 2), crv(u)))
# try start-point
crv = surf.const_par_curve(0.0, 'v')
u = np.linspace(0, 1, 13)
self.assertTrue(np.allclose(surf(u, 0.0).reshape(13, 2), crv(u)))
# try end-point
crv = surf.const_par_curve(1.0, 'v')
u = np.linspace(0, 1, 13)
self.assertTrue(np.allclose(surf(u, 1.0).reshape(13, 2), crv(u)))
