The block header's float at +0x08 gives L and the switch distances are
[D0, D1, D2] = [6L, 4L, 2L] world units -- 192/128/64 on every level
measured. The distance test uses the patch's bounding sphere truncated
to integers against trunc(D * 1024), not the sphere's centre, so a
patch straddling a threshold takes the coarser mode. Six modes result:
LOD 2, LOD 1 collapse, LOD 1 morph, LOD 0 collapse, LOD 0 morph, LOD 0.
A morph weight runs 0 to 1 across its tier's band. Past the far edge an
entry is not blended but replaced by its first parent -- a collapse.
The tested property is that distance never moves back to a finer mode,
swept across the whole range, because that is what keeps terrain from
popping as the camera moves.
The four V4_8 parent arrays are classified by VU address and an
unrecognised address is now an error, which is a real check: all 18,102
patches still parse. Every recorded parent resolves to real vertex info
and real positions, and no common entry claims a parent.
That is as far as it goes, and the limit is a finding rather than a
rounding error. The addresses are not unique: on level 0 patch 1,
unk_indices_2_lod_01_addr == parent_indices_lod_0_addr == 291, with
unk_06 and unk_0a both zero, so nothing but unpacking order separates
them. Across all 27 levels 57,782 of 374,349 LOD entries resolve, and
316,548 unresolved LOD-0 entries against 28,739 resolved is far too
lopsided to be genuine -- either the arrays are misassigned where
addresses collide, or RAC2's positions_lod_0_count means something other
than RAC1's. Only 3,274 of 18,102 patches carry enough V4_8 bytes to
cover positions_lod_01_count + positions_lod_0_count + extras.
The vertex-info tiers themselves are confirmed: the addresses at +9 and
+11 match the observed V4_16 unpacks and the three tier counts sum to
vert_count on every patch, so the header layout is right and it is
specifically the parent arrays that are open. Ruled out so far:
address-only classification (collides) and one-parent-per-position (fails
on 15,000 patches). Not yet tried: ordering by VU address instead of by
declaration, and using unk_06/unk_0a to suppress an empty tier before
falling through. Written up in plan/level-assets.md.
ReaperOfVeriod
2a5307a157