Adriano Dal PastroandClaude Opus 4.7
d1b27433d5
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
89 lines
3.3 KiB
Python
89 lines
3.3 KiB
Python
"""Unit tests for stl_sampler."""
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from __future__ import annotations
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import io
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import struct
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import numpy as np
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import pytest
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from presa_mano.perception.stl_sampler import parse_stl_bytes, sample_surface
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def _make_cube_stl_bytes(side_mm: float = 10.0) -> bytes:
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"""Synthesize a binary STL of an axis-aligned cube centered at origin,
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from -side/2 to +side/2 on each axis. 12 triangles, no normals needed."""
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s = side_mm / 2.0
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v = [
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(-s, -s, -s), ( s, -s, -s), ( s, s, -s), (-s, s, -s),
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(-s, -s, s), ( s, -s, s), ( s, s, s), (-s, s, s),
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]
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# 6 faces x 2 tris (vertex order: any orientation works for our use)
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tris = [
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(0, 1, 2), (0, 2, 3), # z=-s
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(4, 6, 5), (4, 7, 6), # z=+s
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(0, 4, 5), (0, 5, 1), # y=-s
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(3, 2, 6), (3, 6, 7), # y=+s
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(0, 3, 7), (0, 7, 4), # x=-s
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(1, 5, 6), (1, 6, 2), # x=+s
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]
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buf = io.BytesIO()
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buf.write(b"\x00" * 80) # header
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buf.write(struct.pack("<I", len(tris))) # n_triangles
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for (i, j, k) in tris:
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buf.write(struct.pack("<fff", 0.0, 0.0, 0.0)) # normal (unused)
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for idx in (i, j, k):
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buf.write(struct.pack("<fff", *v[idx]))
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buf.write(struct.pack("<H", 0)) # attribute byte count
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return buf.getvalue()
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def test_parse_stl_cube_bbox():
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stl_bytes = _make_cube_stl_bytes(side_mm=10.0)
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verts, tris = parse_stl_bytes(stl_bytes)
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assert verts.ndim == 2 and verts.shape[1] == 3
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assert tris.ndim == 2 and tris.shape[1] == 3
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assert tris.dtype.kind == "i"
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# BB del cubo: [-5, +5] su ogni asse
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np.testing.assert_allclose(verts.min(axis=0), [-5.0, -5.0, -5.0], atol=1e-6)
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np.testing.assert_allclose(verts.max(axis=0), [ 5.0, 5.0, 5.0], atol=1e-6)
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def test_sample_surface_in_bbox():
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stl_bytes = _make_cube_stl_bytes(side_mm=10.0)
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verts, tris = parse_stl_bytes(stl_bytes)
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pts = sample_surface(verts, tris, n=1000, seed=0)
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assert pts.shape == (1000, 3)
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# tutti i punti devono cadere dentro la BB del cubo (più epsilon
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# per il rumore di floating point bary)
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np.testing.assert_array_less(pts.max(axis=0), 5.0 + 1e-4)
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np.testing.assert_array_less(-pts.min(axis=0), 5.0 + 1e-4)
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def test_sample_surface_distribution_uniform():
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"""8 octanti del cubo, ognuno >= 8% dei punti (perfetto = 100/6 ~= 16.7%
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per faccia, distribuita su 4 octanti adiacenti)."""
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stl_bytes = _make_cube_stl_bytes(side_mm=10.0)
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verts, tris = parse_stl_bytes(stl_bytes)
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pts = sample_surface(verts, tris, n=2000, seed=1)
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counts = np.zeros(8, dtype=np.int64)
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for p in pts:
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# bin (x>0, y>0, z>0) -> 0..7
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idx = (int(p[0] > 0) << 2) | (int(p[1] > 0) << 1) | int(p[2] > 0)
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counts[idx] += 1
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frac = counts / pts.shape[0]
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assert (frac > 0.08).all(), f"octant fractions too uneven: {frac}"
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def test_sample_surface_seed_deterministic():
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stl_bytes = _make_cube_stl_bytes(side_mm=10.0)
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verts, tris = parse_stl_bytes(stl_bytes)
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a = sample_surface(verts, tris, n=100, seed=42)
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b = sample_surface(verts, tris, n=100, seed=42)
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np.testing.assert_array_equal(a, b)
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def test_parse_stl_bad_payload_raises():
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with pytest.raises(Exception): # numpy-stl raises various; we just want it to not silently pass
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parse_stl_bytes(b"not a real STL")
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