Function clipMeshToHalfSpace

clipMeshToHalfSpace(
    mesh: MeshData,
    normal: Vec3,
    offset: number,
): HalfSpaceClipResult
Clip one mesh to the half-space dot(worldPoint, normal) <= offset.
Parameters
- mesh: MeshData
- normal: Vec3
  Plane normal (world). Need not be unit — it is normalised internally, and offset is rescaled with it, so the half-space is the same set either way.
- offset: number
  Plane offset: dot(pointOnPlane, normal).
Returns HalfSpaceClipResult

Throws
when normal is (numerically) the zero vector — that defines no half-space at all, and silently keeping everything would print a model the screen is showing cut.