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Fix computation of joint_angles to handle zero division case

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Grant Sanderson 2024-08-21 13:44:00 -05:00
parent 941513d68c
commit 43f1704f69
1 changed files with 17 additions and 15 deletions
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32
manimlib/mobject/types/vectorized_mobject.py
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@ -35,6 +35,7 @@ from manimlib.utils.iterables import resize_array
from manimlib.utils.iterables import resize_with_interpolation
from manimlib.utils.iterables import resize_preserving_order
from manimlib.utils.iterables import arrays_match
from manimlib.utils.simple_functions import fdiv
from manimlib.utils.space_ops import angle_between_vectors
from manimlib.utils.space_ops import cross
from manimlib.utils.space_ops import cross2d
@ -1185,32 +1186,33 @@ class VMobject(Mobject):
a0_to_h = h - a0
h_to_a1 = a1 - h
vect_to_vert = np.zeros(points.shape)
vect_from_vert = np.zeros(points.shape)
# Tangent vectors into each vertex
v_in = np.zeros(points.shape)
# Tangent vectors out of each vertex
v_out = np.zeros(points.shape)
vect_to_vert[1::2] = a0_to_h
vect_to_vert[2::2] = h_to_a1
vect_from_vert[0:-1:2] = a0_to_h
vect_from_vert[1::2] = h_to_a1
v_in[1::2] = a0_to_h
v_in[2::2] = h_to_a1
v_out[0:-1:2] = a0_to_h
v_out[1::2] = h_to_a1
# Joint up closed loops, or mark unclosed paths as such
ends = self.get_subpath_end_indices()
starts = [0, *(e + 2 for e in ends[:-1])]
for start, end in zip(starts, ends):
if self.consider_points_equal(points[start], points[end]):
vect_to_vert[start] = vect_from_vert[end - 1]
vect_from_vert[end] = vect_to_vert[start + 1]
v_in[start] = v_out[end - 1]
v_out[end] = v_in[start + 1]
else:
vect_to_vert[start] = vect_from_vert[start]
vect_from_vert[end] = vect_to_vert[end]
v_in[start] = v_out[start]
v_out[end] = v_in[end]
# Compute dot and cross products
to_dot_from = (vect_to_vert * vect_from_vert).sum(1)
to_norm = np.sqrt((vect_to_vert * vect_to_vert).sum(1))
from_norm = np.sqrt((vect_from_vert * vect_from_vert).sum(1))
angles = np.arccos(to_dot_from / (to_norm * from_norm))
in_dot_out = (v_in * v_out).sum(1)
norm_product = np.sqrt((v_in * v_in).sum(1) * (v_out * v_out).sum(1))
angles = np.arccos(fdiv(in_dot_out, norm_product, zero_over_zero_value=1))
crosses = cross(vect_to_vert, vect_from_vert)
crosses = cross(v_in, v_out)
unit_normal = self.get_unit_normal()
angles[(crosses * unit_normal[np.newaxis, :]).sum(1) < 0] *= -1
self.data["joint_angle"][:, 0] = angles