"""Multi-format mesh loader.
The v3 pressure pipeline ops (``mesh_attach``, ``body_grouping``) accept
the mesh as a file path resolved against the template's root. This
helper handles the path dispatch by suffix:
- ``.lnas`` -> :func:`lnas.LnasFormat.from_file` (preserves authored surfaces)
- ``.stl`` -> :func:`lnas.LnasFormat.from_stl` (single ``"all"`` surface)
- ``.h5`` -> read ``/Triangles + /Geometry``, single ``"all"`` surface
- ``.xdmf`` -> redirect to the sibling ``.h5`` (XDMF is metadata only)
Files that already have authored surface labels (``.lnas``) keep them.
The other formats produce one synthetic ``"all"`` surface covering
every triangle, so YAML templates targeting that surface (or
``surfaces: []`` for "use everything") work uniformly.
"""
from __future__ import annotations
__all__ = ["load_mesh", "mesh_from_h5"]
import pathlib
import h5py
import numpy as np
from lnas import LnasFormat, LnasGeometry
def _resolve_lnas_version() -> str:
"""Pick a version string the installed lnas reader will accept.
lnas exposes ``_CURRENT_VERSION`` (e.g. ``"v0.5.2"``) on
:mod:`lnas.fmt`; we use that when available so cfdmod tracks the
library it's pinned against. If the symbol moves or disappears, fall
back to a hard-coded value compatible with lnas's major-version check.
"""
try:
from lnas import fmt as _lnas_fmt
version = getattr(_lnas_fmt, "_CURRENT_VERSION", None)
if isinstance(version, str) and version:
return version
except Exception:
pass
return "v0.5.2"
_LNAS_VERSION = _resolve_lnas_version()
_DEFAULT_SURFACE_NAME = "all"
[docs]
def mesh_from_h5(h5_path: pathlib.Path) -> LnasFormat:
"""Build an :class:`LnasFormat` from an HDF5 file's ``/Triangles +
/Geometry`` datasets, with one synthetic surface covering every triangle.
Used both by :func:`load_mesh` (for ``.h5``/``.xdmf`` inputs) and as the
fallback when a pipeline call omits ``mesh_path`` and the geometry has to
come straight from the body or cp timeseries file.
"""
with h5py.File(h5_path, "r") as f:
if "Triangles" not in f or "Geometry" not in f:
raise ValueError(
f"{h5_path} has no /Triangles + /Geometry; cannot build a mesh from it."
)
triangles = f["Triangles"][:].astype(np.int32)
vertices = f["Geometry"][:].astype(np.float64)
geom = LnasGeometry(vertices=vertices, triangles=triangles)
surfaces = {_DEFAULT_SURFACE_NAME: np.arange(len(triangles), dtype=np.int32)}
return LnasFormat(version=_LNAS_VERSION, geometry=geom, surfaces=surfaces)
[docs]
def load_mesh(source: pathlib.Path | LnasFormat) -> LnasFormat:
"""Resolve a mesh from any supported source.
Args:
source: Either an :class:`LnasFormat` (returned as-is) or a path
ending in ``.lnas``, ``.stl``, ``.h5``, or ``.xdmf``.
Returns:
LnasFormat ready to drive the pressure pipeline.
"""
if isinstance(source, LnasFormat):
return source
path = pathlib.Path(source)
suffix = path.suffix.lower()
if suffix == ".lnas":
return LnasFormat.from_file(path)
if suffix == ".stl":
return LnasFormat.from_stl(path)
if suffix == ".xdmf":
h5_sibling = path.with_suffix(".h5")
if not h5_sibling.exists():
raise FileNotFoundError(
f"{path} references mesh data but the sibling H5 {h5_sibling} is missing."
)
return mesh_from_h5(h5_sibling)
if suffix == ".h5":
return mesh_from_h5(path)
raise ValueError(
f"Unsupported mesh format {suffix!r} for {path}. Expected one of: .lnas, .stl, .h5, .xdmf."
)
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