intersect_cuts

The segment each entry of intersect_pairs is cut along, one thread per entry. The thread reads the entry's a, b and part and writes the part's two endpoints (intersect_core states the parts). An endpoint record is 8 words: the position as f32 bits, the kind word (the kind in the low byte, which meshes the segment cuts in bits 8 and 9), then lo, hi, tri and extra, which name the crossing; two endpoints, 16 words, an entry. The endpoint slot s = 2 * entry + e names an endpoint to intersect_unify and intersect_retri. A point on a shared edge writes the same record as both endpoints. Exact.

It binds apts, atri, bpts, btri and pairs and writes cut. Over a live count (COUNT=device, see the abi README) an entry past the live ones is not read or written. geometry.boolean runs it.