def actual_intersection(segments, i, j):
segment = segments[i]
other_segment = segments[j]
if is_same(dot_product(points_diff(*segment), points_diff(*other_segment)), 0.0):
return False
for index1, p1 in enumerate(segment):
for index2, p2 in enumerate(other_segment):
if is_same(p1, p2):
segment1 = segments[i - 1][index1], segments[(i + 1) % len(segments)][index1]
segment2 = segments[j - 1][index2], segments[(j + 1) % len(segments)][index2]
if have_common_point(segment1, segment2):
return False
if not segments_are_intersecting(segment1, segment2):
return False
# ==
if index1 == 0:
connected_segment1 = segments[i - 1]
else:
connected_segment1 = segments[(i + 1) % len(segments)]
if index2 == 0:
connected_segment2 = segments[j - 1]
else:
connected_segment2 = segments[(j + 1) % len(segments)]
if is_same(
cross_product(points_diff(*connected_segment1), points_diff(*other_segment)), 0.0
) or is_same(cross_product(points_diff(*connected_segment2), points_diff(*segment)), 0.0):
return False
center = p1
if _is_in_angle(segment1[0], center, segment1[1], segment2[0]) == _is_in_angle(
segment1[0], center, segment1[1], segment2[1]
):
return False
for index1, p1 in enumerate(segment):
if is_on_segment(other_segment[0], other_segment[1], p1):
full_segment = (segments[i - 1][index1], segments[(i + 1) % len(segments)][index1])
if have_common_point(other_segment, full_segment):
return False
if not segments_are_intersecting(full_segment, other_segment):
return False
for index2, p2 in enumerate(other_segment):
if is_on_segment(segment[0], segment[1], p2):
full_segment = (segments[j - 1][index2], segments[(j + 1) % len(segments)][index2])
if have_common_point(segment, full_segment):
return False
if not segments_are_intersecting(full_segment, segment):
return False
return True
def _is_in_angle(p1, center, p2, point_to_check):
v1 = normalize(points_diff(center, p1))
v2 = normalize(points_diff(center, p2))
v = normalize(points_diff(center, point_to_check))
return cross_product(v1, v) <= PRECISION and cross_product(v2, v) >= PRECISION
