Reuse one THREE.Line + preallocated position buffer per guide slot, mutating
endpoints in place each drag tick instead of rebuilding the geometry, line, and
two Vector3s and re-uploading the GPU buffer every frame. Key guides by a stable
semantic id (sill / head / gap:side / vertical / spacing:i) so a slot that
persists keeps its React element and drei <Html> pill mounted as the guide set
churns, rather than remounting under shifting index keys.
Also: make useOpeningGuides.clear() a no-op when already empty so the common
no-guide hover frame doesn't push a fresh [] and re-render to the same nothing;
dispose the move-tool cursor EdgesGeometry on unmount; and memoize the
placement-tool cursor EdgesGeometry (static fallback dims) so it isn't
reallocated and orphaned on every render during placement.
Reviewed by Codex (peer + adversarial): no correctness, hook-order, or GPU-leak
regressions.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
