nx_stl_test.nx

nx_stl_test.nx -- hand-build a binary STL tetrahedron in-memory, parse it back, verify everything round-trips correctly. Tetrahedron at unit-millimetre scale (becomes Q14 = 16384 after parse): v0 = (0, 0, 0) v1 = (1, 0, 0) v2 = (0, 1, 0) v3 = (0, 0, 1) Triangles (CCW outward winding matching nx_mesh_make_tetrahedron): T0: v1, v2, v3 (far face) T1: v0, v3, v2 (x=0 face) T2: v0, v1, v3 (y=0 face) T3: v0, v2, v1 (z=0 face) Each triangle = 50 bytes: 12 bytes normal (we write zeros; parser ignores them) 36 bytes 9 floats for 3 verts 2 bytes attribute (zero) Total file size = 80-byte header + 4-byte n_tris + 4*50 = 284 bytes. Closed-form invariants: (a) parse returns OK verdict (b) n_tris_header == 4 (c) n_verts_unique == 4 (perfect dedup -- tetrahedron really does have exactly 4 unique vertices) (d) mesh.n_tris == 4 (e) parsed coordinates match expected Q14 values (f) nx_mesh_is_manifold returns OK on the parsed mesh (g) Truncated buffer detected (h) ASCII STL detected and refused expect_exit: 0 license_tier: ORIGINAL