Load a baked environment map from the store's root-level environment/ sidecar
group (luxar env attach; spec MESH_PHYSICAL_MATERIALS_SPEC.md §3.3).
The group carries neither type nor kind, so build-scene-graph.ts skips it as a
metadata sidecar — nothing reads it implicitly, which is why this loader exists. Its
faces attr names the live array (faces-<digest>; a re-bake is a NEW path, so a
caching store can never serve stale faces), and scene_content_hash is the guard:
the environment group is EXCLUDED from the scene digest on the Python side, so this
comparison against the root's content_hash is exact. A mismatch means the scene
changed since the bake; the map is ignored with a console line and the viewer falls
back to its configured source or the room.
Absence is the normal case and costs NO request when a root index fetched from the
network this load is available: luxar env attach re-consolidates after writing the
group, so a FRESH index is authoritative and one that lists no environment node
means there is none. A CACHED index is not: the L2 tier revalidates the root only by
content_hash, which env attach deliberately leaves unchanged, so a warm cache can
keep serving the pre-attach index. On a warm load of a format-3 store the scene loader
still has this load's network copy of the index (the load-time root-document fetch;
data/scene-loader/cache/root-listing.ts). Only without one (format 2, a presigned
or zipped source) is the group probed — one document of the store's known format —
and a genuine absence is remembered per dataset for the session, so a revisit does
not pay it again. When the source is unreachable, a cached map is used if
available. Other failures degrade to "no baked map" without failing the scene load.
Load a baked environment map from the store's root-level
environment/sidecar group (luxar env attach; specMESH_PHYSICAL_MATERIALS_SPEC.md§3.3).The group carries neither
typenorkind, sobuild-scene-graph.tsskips it as a metadata sidecar — nothing reads it implicitly, which is why this loader exists. Itsfacesattr names the live array (faces-<digest>; a re-bake is a NEW path, so a caching store can never serve stale faces), andscene_content_hashis the guard: the environment group is EXCLUDED from the scene digest on the Python side, so this comparison against the root'scontent_hashis exact. A mismatch means the scene changed since the bake; the map is ignored with a console line and the viewer falls back to its configured source or the room.Absence is the normal case and costs NO request when a root index fetched from the network this load is available:
luxar env attachre-consolidates after writing the group, so a FRESH index is authoritative and one that lists noenvironmentnode means there is none. A CACHED index is not: the L2 tier revalidates the root only bycontent_hash, whichenv attachdeliberately leaves unchanged, so a warm cache can keep serving the pre-attach index. On a warm load of a format-3 store the scene loader still has this load's network copy of the index (the load-time root-document fetch;data/scene-loader/cache/root-listing.ts). Only without one (format 2, a presigned or zipped source) is the group probed — one document of the store's known format — and a genuine absence is remembered per dataset for the session, so a revisit does not pay it again. When the source is unreachable, a cached map is used if available. Other failures degrade to "no baked map" without failing the scene load.