Module intersection_graph

Structs§

IntersectionGraph: Everything classification and assembly need.
Piece: One output fragment: a sub-triangle of an arranged input triangle, or an untouched whole triangle. v is wound to match the input mesh’s outward orientation; vi are the interned ids of the same three vertices.
VertInterner: Exact-point interner: one id per distinct point, with two disjoint key spaces. f64-representable points (all input vertices, and any constructed point that rounds exactly) key on their coordinate bits — no rational hashing, so untouched input triangles intern for the cost of a HashMap probe. Only genuinely non-representable constructed points use the rational map. verts_f64 caches the correctly rounded approximation of every id (exact for bit-keyed points), which downstream float filters and output assembly reuse instead of re-rounding. Order invariance: both maps are probe-only (get/entry, never iterated); ids come from verts.len() at insertion time, so they depend only on the sequential call order, not on the hasher.

build_graph: Build the intersection graph for soups p and q (each triangle wound outward; degenerate triangles are dropped here, paper §5).
build_graph_with_progress: build_graph_with_token that also reports its five phases to progress (see crate::progress). None is exactly build_graph_with_token: no counter is touched and no branch is taken inside any inner loop.
build_graph_with_token: build_graph with cooperative cancellation. Returns None when the token fires. Checks run per triangle in every phase and inside the arrangement sweeps — heavily self-intersecting inputs spend minutes in per-triangle quadratic loops, and a cancel that only top-level phases notice can overshoot its deadline by that much (Thingi10K #42211 ran 565 s past a 60 s cancel before this plumbing).
edge_key

EdgeKey: Canonical (sorted) edge between two interned vertex ids. Downstream stages (classify rings, propagate flood fill) key their maps on these integers instead of exact rational point pairs — vertex interning at piece-emission time makes id equality coincide with exact geometric identity.