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Uni-Lab-OS/unilabos/layout_optimizer/tests/test_obb.py
2026-04-02 13:24:45 +08:00

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Python

"""Tests for OBB (Oriented Bounding Box) geometry utilities."""
import math
import pytest
from ..obb import obb_corners, obb_overlap, obb_min_distance, segment_obb_intersection_length
class TestObbCorners:
"""obb_corners(cx, cy, w, h, theta) → 4 corner points of the rotated rectangle."""
def test_no_rotation(self):
"""Axis-aligned box at origin: corners at ±half extents."""
corners = obb_corners(0, 0, 2.0, 1.0, 0.0)
assert len(corners) == 4
xs = sorted(c[0] for c in corners)
ys = sorted(c[1] for c in corners)
assert xs == pytest.approx([-1.0, -1.0, 1.0, 1.0])
assert ys == pytest.approx([-0.5, -0.5, 0.5, 0.5])
def test_90_degree_rotation(self):
"""90° rotation swaps width and height extents."""
corners = obb_corners(0, 0, 2.0, 1.0, math.pi / 2)
xs = sorted(c[0] for c in corners)
ys = sorted(c[1] for c in corners)
assert xs == pytest.approx([-0.5, -0.5, 0.5, 0.5])
assert ys == pytest.approx([-1.0, -1.0, 1.0, 1.0])
def test_offset_center(self):
"""Corners shift by (cx, cy)."""
corners = obb_corners(3.0, 2.0, 2.0, 1.0, 0.0)
xs = sorted(c[0] for c in corners)
ys = sorted(c[1] for c in corners)
assert xs == pytest.approx([2.0, 2.0, 4.0, 4.0])
assert ys == pytest.approx([1.5, 1.5, 2.5, 2.5])
def test_45_degree_rotation(self):
"""45° rotation: corners on diagonals."""
corners = obb_corners(0, 0, 2.0, 2.0, math.pi / 4)
for cx, cy in corners:
dist = math.sqrt(cx**2 + cy**2)
assert dist == pytest.approx(math.sqrt(2), abs=1e-9)
class TestObbOverlap:
"""obb_overlap(corners_a, corners_b) → True if the two OBBs overlap."""
def test_separated_boxes(self):
"""Two boxes far apart: no overlap."""
a = obb_corners(0, 0, 1.0, 1.0, 0.0)
b = obb_corners(5, 0, 1.0, 1.0, 0.0)
assert obb_overlap(a, b) is False
def test_overlapping_boxes(self):
"""Two boxes sharing space: overlap."""
a = obb_corners(0, 0, 2.0, 2.0, 0.0)
b = obb_corners(1, 0, 2.0, 2.0, 0.0)
assert obb_overlap(a, b) is True
def test_touching_edges_no_overlap(self):
"""Boxes touching at edge: no overlap (strict <, not <=)."""
a = obb_corners(0, 0, 2.0, 2.0, 0.0)
b = obb_corners(2.0, 0, 2.0, 2.0, 0.0)
assert obb_overlap(a, b) is False
def test_rotated_overlap(self):
"""One box rotated 45°, overlapping the other."""
a = obb_corners(0, 0, 2.0, 2.0, 0.0)
b = obb_corners(1.0, 1.0, 2.0, 2.0, math.pi / 4)
assert obb_overlap(a, b) is True
def test_rotated_no_overlap(self):
"""One box rotated 45°, separated from the other."""
a = obb_corners(0, 0, 1.0, 1.0, 0.0)
b = obb_corners(3, 0, 1.0, 1.0, math.pi / 4)
assert obb_overlap(a, b) is False
def test_identical_boxes(self):
"""Same position and size: overlap."""
a = obb_corners(1, 1, 1.0, 1.0, 0.0)
b = obb_corners(1, 1, 1.0, 1.0, 0.0)
assert obb_overlap(a, b) is True
class TestObbMinDistance:
"""obb_min_distance(corners_a, corners_b) → minimum edge-to-edge distance."""
def test_overlapping_returns_zero(self):
"""Overlapping boxes: distance = 0."""
a = obb_corners(0, 0, 2.0, 2.0, 0.0)
b = obb_corners(1, 0, 2.0, 2.0, 0.0)
assert obb_min_distance(a, b) == pytest.approx(0.0)
def test_separated_axis_aligned(self):
"""Two axis-aligned boxes with 2m gap."""
a = obb_corners(0, 0, 2.0, 2.0, 0.0) # edges at x=±1
b = obb_corners(4, 0, 2.0, 2.0, 0.0) # edges at x=3,5
# Gap = 3 - 1 = 2.0
assert obb_min_distance(a, b) == pytest.approx(2.0)
def test_diagonal_separation(self):
"""Boxes separated diagonally: distance to nearest corner."""
a = obb_corners(0, 0, 2.0, 2.0, 0.0) # corners at (±1, ±1)
b = obb_corners(4, 4, 2.0, 2.0, 0.0) # corners at (3..5, 3..5)
# Nearest corners: (1,1) to (3,3) → sqrt(8) ≈ 2.828
assert obb_min_distance(a, b) == pytest.approx(math.sqrt(8), abs=0.01)
def test_rotated_separation(self):
"""One rotated box separated from axis-aligned box."""
a = obb_corners(0, 0, 1.0, 1.0, 0.0)
b = obb_corners(3, 0, 1.0, 1.0, math.pi / 4)
dist = obb_min_distance(a, b)
assert dist > 0
def test_touching_returns_zero(self):
"""Touching edges: distance = 0."""
a = obb_corners(0, 0, 2.0, 2.0, 0.0)
b = obb_corners(2.0, 0, 2.0, 2.0, 0.0)
assert obb_min_distance(a, b) == pytest.approx(0.0)
class TestSegmentOBBIntersectionLength:
"""segment_obb_intersection_length: Cyrus-Beck clipping."""
def test_segment_fully_outside(self):
corners = obb_corners(0, 0, 2, 2, 0)
length = segment_obb_intersection_length((-5, 3), (5, 3), corners)
assert length == 0.0
def test_segment_fully_inside(self):
corners = obb_corners(0, 0, 4, 4, 0)
length = segment_obb_intersection_length((-0.5, 0), (0.5, 0), corners)
assert abs(length - 1.0) < 1e-6
def test_segment_crosses_through(self):
corners = obb_corners(0, 0, 2, 2, 0)
length = segment_obb_intersection_length((-5, 0), (5, 0), corners)
assert abs(length - 2.0) < 1e-6
def test_segment_partial_overlap(self):
corners = obb_corners(0, 0, 2, 2, 0)
length = segment_obb_intersection_length((0, 0), (5, 0), corners)
assert abs(length - 1.0) < 1e-6
def test_rotated_obb(self):
corners = obb_corners(0, 0, 2, 2, math.pi / 4)
length = segment_obb_intersection_length((-3, 0), (3, 0), corners)
expected = 2 * math.sqrt(2)
assert abs(length - expected) < 1e-4
def test_zero_length_segment(self):
corners = obb_corners(0, 0, 2, 2, 0)
assert segment_obb_intersection_length((0, 0), (0, 0), corners) == 0.0
def test_parallel_outside(self):
corners = obb_corners(0, 0, 2, 2, 0)
length = segment_obb_intersection_length((-5, 2), (5, 2), corners)
assert length == 0.0