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74 lines
2.0 KiB
Python
74 lines
2.0 KiB
Python
from panda3d.core import Triangulator
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def triangulate(vertices):
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t = Triangulator()
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for i, v in enumerate(vertices):
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t.add_vertex(v)
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t.add_polygon_vertex(i)
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t.triangulate()
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# Make sure that the result is consistent by starting each triangle with
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# the lowest index value. That makes it easier to use predetermined values
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# in the test cases.
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result = set()
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for n in range(t.get_num_triangles()):
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# Switch to lowest matching index value in case of duplicates.
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v0 = vertices.index(vertices[t.get_triangle_v0(n)])
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v1 = vertices.index(vertices[t.get_triangle_v1(n)])
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v2 = vertices.index(vertices[t.get_triangle_v2(n)])
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if v1 < v0:
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v0, v1, v2 = v1, v2, v0
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if v1 < v0:
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v0, v1, v2 = v1, v2, v0
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result.add((v0, v1, v2))
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return result
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def test_triangulator_degenerate():
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assert not triangulate([])
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assert not triangulate([(0, 0)])
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assert not triangulate([(0, 0), (0, 0)])
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assert not triangulate([(0, 0), (1, 0)])
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assert not triangulate([(0, 0), (0, 0), (0, 0)])
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assert not triangulate([(0, 0), (1, 0), (1, 0)])
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assert not triangulate([(1, 0), (1, 0), (1, 0)])
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assert not triangulate([(1, 0), (0, 0), (1, 0)])
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assert not triangulate([(0, 0), (0, 0), (0, 0), (0, 0)])
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def test_triangulator_triangle():
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assert triangulate([(0, 0), (1, 0), (1, 1)]) == {(0, 1, 2)}
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def test_triangulator_tail():
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# This triangle has a long "tail" where the polygon retraces its vertices.
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assert triangulate([
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(0, -1),
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(0, 1),
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(1, 0),
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(2, 0),
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(3, 1),
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(4, 0),
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(5, 0),
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(4, 0),
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(3, 1),
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(2, 0),
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(1, 0),
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]) == {(0, 2, 1)}
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def test_triangulator_hourglass():
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# Two triangles with touching tips, effectively.
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assert triangulate([
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(-1, 1),
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(-1, -1),
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(0, 0),
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(1, -1),
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(1, 1),
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(0, 0),
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]) == {(0, 1, 2), (2, 3, 4)}
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