v0.3.0

Half-edge–primary mesh processing

The half-edge is now the working representation and faces is a derived
snapshot, so a multi-stage pipeline pays one HalfMesh::Build instead of one
per family transition. On a 5 M-face mesh a native clean (spurious → spikes →
holes → unref) performs exactly one build and one face harvest; tests/perf
asserts both counts.

• Representation contract — Mesh has exactly three valid states
  (arrays-only, half-edge-only, both-and-consistent), enforced by
  ValidateInvariants(), with InvalidateFaces() / SyncFaces() /
  InvalidateHalfMesh() and a BeginHalfEdgePipeline() scope that defers
  per-stage snapshots to one final harvest.
• New HalfMesh primitives — FRemoveBulk, FAddDisk,
  VRemoveUnreferenced; FAdd accepts isolated corners and unwinds through an
  undo log, so a rejected add leaves every array byte-identical.
• Native repair/hole stages — the whole repair, spike, hole-closing and
  unreferenced-vertex family mutates the live half-edge instead of clearing it.
• Simplify and RemeshIsotropic read topology from halfMesh only.

Performance

HalfMesh::Build pairs twins through a flat open-addressing table keyed by a
packed (min,max) vertex pair instead of std::unordered_map: 3.24× faster
(0.608 s vs. 1.969 s) at 495.8 MiB vs. 904.2 MiB peak on a 5,003,552-face mesh
(Release, MSVC 14.51, x64, i7-13700KF). Half-edge numbering, rejection behavior
and goldens are unchanged.

New

• RemoveSpuriousComponents(factor), RemoveSpikes(maxIterations),
  RemoveVerticesAndFill(vertexRemoves), RemoveFacesHalfEdge,
  ComputeMeanEdgeLength.
• RectPacking.h — PackRectangles / EstimateSquareTextureSize: the atlas
  packer's two-tier skyline+shelf core over integer pixel rectangles, with no
  mesh involved.
• HalfMesh::BuildCount() / FFacesCount() so a pipeline can assert it
  rebuilds connectivity once.
• Mesh::vertexNormals — authored per-vertex normals, transported rather
  than maintained. Parallel to vertices under the same contract as
  vertexColors, but explicitly not a cache: nothing recomputes it, so an
  empty array means "derive them yourself". It is remapped through every
  operation that only renumbers vertices and dropped by every operation that
  moves one. The openMVS bridge now carries normals in both directions, so a
  round trip no longer replaces an artist's normals with geometric ones.
• BakeOntoAtlas(source, target, params) — RebakeTexture's counterpart
  for a target whose UV layout is authored and must be preserved: it reads
  target.faceTexcoords instead of generating a new atlas, so only the texels
  change.
• BakeParams::faceMask — restrict rasterization to selected target faces.
  Under a mask each page is seeded from target.texturesDiffuse rather than
  black, so unselected texels keep what they had and the bake is a true
  in-place edit of one region of an existing texture.

Breaking changes

• CloseHoles changed meaning — the first parameter is now maxHoleEdges
  (default 30), a size threshold, not the old nCloseHoles = 200 count.
  A scanned surface's large open boundary now stays open by default.
• vertexColors is a contractual parallel array — empty, or exactly as long
  as vertices, enforced by ValidateInvariants().
• faceTexblobs is std::vector<Mesh::TexIndex> (uint8), matching openMVS's
  MVS::Mesh::TexIndex; MAX_TEXBLOBS is 255. The PLY on-disc property stays
  int32, so existing files are unaffected.
• SaveGLTF takes imageFormat and embedImages (defaulted to the previous
  embedded-JPEG behavior).
• glTF save → load is now an identity. LoadGLTF previously applied
  SaveGLTF's z-up → y-up root-node matrix like any other node transform and
  returned the mesh rotated 90° about X, so the library could not read back what
  it had just written. It now converts back to z-up after flattening the node
  hierarchy. The rotation stays in the file, so exports remain upright in
  Blender, three.js and Cesium. halfmesh is z-up in memory, its glTF files are
  y-up is now a stated, fixed contract rather than an implied one. A y-up glTF
  from any exporter loads correctly; a glTF carrying z-up data under an identity
  node — non-conformant, but emitted by some writers, including openMVS's own
  pre-halfmesh exporter — loads rotated and must be corrected by its producer.
  PLY is unaffected.
• A caller that hand-edits the public faces array must call
  InvalidateHalfMesh() — the old count heuristic is gone.
• Not ABI-compatible with 0.2.0 — recompile against the new headers.

Also

• openMVS interop gained consuming ConvertMesh overloads (rvalue source), so a
  conversion peaks at the larger mesh plus one array rather than both at once.
• vcpkg builtin-baseline advanced to 0ac8df3b; the vcpkg-overlay-ports/
  tinygltf hotfix is gone — a cold-cache build resolves everything from the
  registry.
• LoadPLY kept the previous mesh's optional arrays whenever the new file
  carried none, leaving them the wrong length against the new vertex and face
  counts; both loaders now reset the optional set up front.
• tinygltf is now built with TINYGLTF_NOEXCEPTION / JSON_NOEXCEPTION, so glTF
  JSON parsing no longer needs exceptions. OpenCV and tinyply still throw, so the
  library as a whole is not yet buildable with exceptions disabled.
• glTF textures are decoded and encoded with OpenCV imgcodecs instead of the
  bundled stb codecs (TINYGLTF_NO_STB_IMAGE / _WRITE) — one image path for PLY
  sidecars and glTF textures alike, and no stb compiled into the build at all.
  JPEG export keeps the quality stb hardcoded, so file output is unchanged.

Full detail: CHANGELOG.md.

Python wheels

manylinux_2_28 x86_64 wheels for CPython 3.10–3.13 are attached below:

pip install https://github.com/cdcseacave/halfmesh/releases/download/v0.3.0/halfmesh-0.3.0-cp312-cp312-manylinux_2_28_x86_64.whl