Module stream_meta 

Shared streaming pre-pass meta resolution.

The browser pre-passes (buildPrePassOnce / buildPrePassStreaming in wasm-bindings) each need the same bundle of load-time metadata before workers can start meshing: the length/plane-angle unit scales, the RTC (relative-to-centre) frame, and the building rotation from IfcSite. This module is the single home for that resolution logic so the three call sites can no longer drift.

Only the RESOLUTION logic lives here — the wasm side keeps ownership of WHEN the resulting StreamMeta is emitted. In particular the streaming pre-pass still emits its meta event MID-SCAN (as soon as META_EMIT_JOB_THRESHOLD geometry jobs are buffered, near the top of the file) so workers spin up early — the ~17 s → ~3 s time-to-first-geometry win on a 986 MB file. This helper does not change that timing; it only factors out the two-vs-three-stage RTC ladder that the two emission sites previously copied.

Everything here COMPOSES the existing canonical primitives: resolve_unit_scales, EntityDecoder::seed_unit_scales, GeometryRouter::with_scale, GeometryRouter::detect_rtc_anchor_for_file, GeometryRouter::detect_rtc_offset_for_file, the shared coord_is_large predicate inside the ladder, and MeshFrame::select for the frame the ladder’s answer turns into.

Structs

StreamMeta

The load-time metadata both pre-passes emit before workers start meshing.

Enums

MetaMode

Which RTC-detection ladder resolve_stream_meta should run.

Functions

resolve_stream_meta

Resolve the full StreamMeta bundle for one pre-pass emission point.