All 18 blobs are byte-identical: the per-stage naming is nominal, and every
stage points at one shared 1675148-byte library stored eighteen times. That
identical size was the reason to open the item, and it turned out to be the
answer to it.
Record layout: {u32 size, u32 name_len, char name[name_len], u32 nv, u32 nt,
f32[3] x nv, u32[3] x nt}, next record at off + 8 + size. The indices are u32
here where MCOL uses u16 -- two different serialisers in one archive.
What makes this a decode rather than a plausible reading: the walk consumes the
file to the byte over 158 variable-length records, with the size word predicted
from the two counts 158/158. A wrong field would desynchronise within a few
records and could not land exactly on the end. All indices in range 158/158;
98.24% of edges shared by exactly two triangles; 147/158 fully manifold.
158 meshes, 90 836 triangles: per-part ship proxies (_bdy/_brg/_eng/_wep/_sld,
the XBG7 sub-part vocabulary) plus 46 stage asteroid meshes whose prefixes are
exactly the stages that have an _AsteroidVolume_wp MCOL.
Two things this file makes me walk back:
* The "1 unit = 1 metre" reading from mapmesh_box_500km is downgraded to
amber. The 500000 arithmetic stands, but it implies that a craft the game's
own tables call "small" is 133 m and that rob_f002 is 447 km -- 89% of the
arena width. The format check survives; the interpretation has no
independent support.
* The _cmesh <-> render-model name link is recorded as UNTESTED, not
confirmed: only one .xbg build manifest survives on the disc, so matching
stems against object names covers 4 of 158, which is no coverage at all.
The names live outside MiscBin: they are the MapPath / MapMesh /
CollisionMeshes field values of the per-stage StageResource object (IDXD schema
3c9ae32e, in every GP_MAIN_GAME_<lang>.pak), and each hashes with the ordinary
pak name_hash straight to a TOC entry. 40/40 resolve, no collisions -- the 11
REGN as <stem>.rgn, the 11 MCOL as <stem>.col, and the 18 remaining blobs as
CollisionSet_S01..S16 / _Tutorial / _test.bin. The .pe string table at 651540
was the way in: MapMesh and MapPath sit adjacent there.
This upgrades the pairing claim. The first section of mcol-collision.md could
only say REGN and MCOL had matching *distributions* of bbox and cell size, and
flagged that as not an object-to-object link. A phase record names one .rgn and
one .col, and all 11/11 pairs share a stem and agree exactly on both.
The names also check the format work from outside it: mapmesh_box_500km.col is
the object decoded here as 8 vertices and 12 triangles spanning exactly
+-250000, and its name says that cube is 500 km across -- so one world unit is
one metre, and a wrong stride could not have produced a box that measures what
its own filename claims. 70 of the 87 phases use it: most stages' only
collision is the arena wall, and _AsteroidVolume_ names the rest.
Still open: the 18 CollisionSet_*.bin are named but not decoded (all exactly
1675148 bytes), and CMapColliderBridge in the RTTI names the runtime consumer
without following it into the code.
The 0x50 header word, which the first section of this page had dismissed as "a
large value", is two u16 counts: vertices and triangles. They give the two
remaining blocks their stride, and every derived length is exact in 11/11 --
len(0x54) == align16(12*nv), len(0x58) == align16(6*nt), and nt equals the
bounding-sphere count decoded last iteration.
Checks that cannot pass by accident:
* sphere i is the TIGHT bounding sphere of triangle i, 4768/4768, with
max|v-c|/r median 0.99990 (a fixed 1.0001 epsilon), against a 1.32%
random-triangle control;
* the mesh is watertight -- every edge shared by exactly two triangles,
7152/7152, zero degenerate triangles, zero unreferenced vertices;
* the two smallest objects are 8 vertices and 12 triangles whose positions
are the eight +-250000 corners of the map bbox: a bare bounding cube.
The cell lists are a correct broad phase: with an exact triangle/box SAT test
only 3 overlapping triangles in 18 577 entries are absent, so a query walking
one cell's list cannot miss a hit. The 730 conservative extras bracket the
builder's own test between exact-SAT and AABB, which retires the 18 unexplained
"sphere misses" from the previous commit as that same margin.
mcol_probe.py gains `mesh` and `obj`; `verify` now runs all three checks and its
output is recorded in docs/re/data/mcol-verify.txt.
The unexplained ~0.75 ratio left at the end of the last iteration was my own
stride. I had read the block as 12-byte points because REGN's vertex section
is 12 bytes, and never checked it: len(0x5C) is not a multiple of 12 in 5 of
the 11 objects, so that stride was never arithmetically possible.
At stride 16 the relation is exact in 11/11 -- max u16 == len(0x5C)/16 - 1 --
and the record reads as {centre f32[3], radius f32}. Powered test, since a
u16 is reached through a specific grid cell: the sphere it names reaches that
cell in 18 559/18 577 = 99.90%, against a 12.02% random-sphere control. Both
fields carry signal (centre alone 26.75%, radius shuffled 70.19%).
The converse -- is the list *exactly* the intersecting set? -- is 0.38%, which
is the expected direction: a bounding sphere is conservative, so membership
implies overlap but not the reverse. The tighter geometry is in 0x54/0x58,
still undecoded. 18 entries (0.10%) go the wrong way and are recorded as open.
tools/re-capture/regn_decode.py is copied unchanged from auto/regn-reader so
the probe's POF0 reader is the known-good one rather than a second copy.
Two tests. Counts modulo 3 are spread across all three residues (639/2063/1786),
so the u16 array is not a triangle list. And a B record is reached through a
specific cell, so a point it references should lie in that cell -- referenced
points score 0.79% against a 0.48% random-point control. Chance.
The contrast is the point. One section earlier the same u16 entries scored
18379/18379 (100%) on 'are these valid point indices'. I flagged that at the
time as the weak bound-check and recorded it as consistent rather than as a
finding. The caution was right: the powered version of the same question now
returns chance, and had the 100% been written up as the decode this page would
carry a confident false statement about MCOL's geometry.
Fifth appearance of the pattern across REGN and MCOL and the first time both
halves have been run on the same field, so the page now states it plainly: a
bound-check asks whether something could be an index, and the answer is set by
the size of the target collection rather than by the field's meaning.
Datum for the next attempt: the maximum u16 is consistently about 0.75x the
point count (923/1232, 1019/1360, 1163/1552, 59/80), too consistent to be
coincidence and not explained.
Two corrections got there. MCOL has 9020 relocated words and only 4488 are
A-record pointers; I assumed the rest sat at B+8 mirroring A, refuted 0/4488.
Measuring their offset from the nearest preceding B record gives B+4 for 4488
(99.0%) and 44 before the first B -- exactly the four header pointers times 11
objects. Nothing unaccounted for.
So B is {u32 count, pointer at +4}. The pointers advance by exactly twice the
count: 4477/4477 (100.00%) over all 11 objects. That is a packed u16 array with
no padding, and it is the load-bearing evidence -- an exact arithmetic identity
over 4477 consecutive pairs. The companion check that those u16s are valid point
indices is the same weak bound-check flagged earlier and is recorded as
consistent rather than as evidence.
Chain: position -> cell -> A {cell index, count 1, ->B, sphere} -> B {count n,
->u16[n]} -> n indices into the point block. Same shape as REGN's cell -> item
-> refs -> geometry.
Open: the 0x54 and 0x58 blocks, which this chain never reaches, and what the
indexed points form.
Filtering array A by the cell-index criteria and following each pointer: every A
record points at a distinct B record, 11/11, and every A count field is exactly
1, 11/11. Per object the A-record count is the number of occupied cells (110 to
575) and the counts sum to it exactly.
That is the same design REGN uses -- the corpus already records 'every occupied
cell has count exactly 1' there. Two sibling formats, one convention, and a
further independent confirmation of the A reading since the filter and the
cardinality are unrelated criteria.
Array B resisted, and both attempts failed in ways worth recording. The record
boundary was off by 8 again, producing records that start with the tail of the
previous structure -- the same mistake as the 0x74 check two iterations ago. And
the u16-index test had no power: the 0x5C block holds ~1232 points, so 'is this
u16 below the point count' passes for almost any small value, and duly reported
100% at seven offsets. Fourth time in these two formats that a bound-check
against a large collection produced a meaningless 100%.
Recorded what would have power instead: B records are 1:1 with occupied cells
and A carries that cell's bounding sphere, so a B field can be tested for
spatial consistency with that specific cell.
Separating the two interleaved arrays by address and re-running the same three
criteria: array A (2509 records) gives byte3==1 at 100.00%, a valid cell index
at 100.00%, and the sphere reaching that cell at 99.92%. Array B (6467) gives
30.65% and 30.60% -- a different record type, and the control showing A's 100%
is not what any 32-byte block would score.
So array A is the per-cell record: cell index (x,y,z), count, pointer into array
B, bounding sphere -- the same role REGN's section 3 plays. That confirms the
earlier 50% was the interleaving artifact and not a half-working reading.
The split was crude, first-half-by-address giving 2509 vs 6467 rather than an
even cut, and A still came out at 100%. A rough partition isolating a perfect
population is stronger than a careful one isolating a good-ish population.
Array B's layout is still unread.
Read as 8 big-endian words, word 0 as four bytes is (x,y,z,1) -- a 3-D cell
index, matching the object's 5x5x5 grid. Words 4-6 are a position and word 7 a
positive scalar (a bounding sphere); word 1 is a count, word 2 the relocated
pointer. Every record pointer lands in the same region, 8976/8976, each a fixed
distance on with the same stride -- so there are two parallel arrays, A and B.
The 50% is the tell. Three independent criteria -- byte 3 == 1, valid cell
index, sphere reaches that cell -- all land on 50.0%, which says half the
records are not this type rather than that the reading half-works. The POF0 slot
list interleaves both arrays and I was testing B's records against A's layout.
So array A is a per-cell record, the same role REGN's section 3 plays. Array B
is unread, and the criteria have not yet been re-run on A alone -- if the
reading is right they should go to 100%.
Used the known-good decoder rather than my own broken one. My version had three
errors: the delta stream starts at table+16 not +8, the tag bits are
0x40/0x80/0xC0 rather than 0/1/2, and slots carry the +16 fixup base. Sanity
check passes -- on REGN the tool returns header slots 0x70-0x84 exactly.
On MCOL, over all 11: the header-region relocated slots are exactly 0x54, 0x58,
0x5C and 0x74 (11/11); 0x5C resolves to 0x80, the first byte after the header
(11/11); and 0x74 resolves to eight bytes before the first array pointer (10/11).
So MCOL has four top-level pointers where REGN has six.
92.7% of gaps between consecutive relocated words are 32 bytes, in 7-127
contiguous runs per object, which with the 0x74 offset reads as arrays of
32-byte records each carrying a pointer at +8.
The four targets are two float blocks, a block of small ints / u16 pairs, and
counts followed by the record array -- the shape of a mesh, stated as a reading
of the shape since none of the blocks is decoded.
Open: the record layout, what the index block indexes, the one object where 0x74
does not land 8 before the array, and whether the 7.3% non-32 gaps are just run
boundaries.
MCOL sits beside REGN in hidden/MiscBin.pak, 11 of each, never decoded. Over all
11: POF0 at data_size+16 11/11, bbox pad words 1.0/1.0/0.0 11/11, and
extent == max-min 11/11. So the header prefix is the same shape as REGN's and
the POF0 mechanism applies, which means the chunk+0x10 base and the loader's own
pointer list -- the two things that cracked REGN -- are available here too.
The map parameters are not merely similar but identical in distribution: bboxes
2/6/3 at 250k/50k/25k and the 0x40 triple 2 at 50000 and 9 at 10000, matching
REGN exactly. Eleven maps, each with an MCOL and a REGN over the same volume at
the same cell size. Noted that this matches distributions, not a demonstrated
object-to-object pairing.
Everything past 0x40 diverges from REGN and is open. Also recorded that my own
POF0 delta decoder is wrong here -- eight leading zero deltas -- and that the
working one is regn_decode.py on auto/regn-reader, which should be used rather
than re-derived. Re-deriving it is the mistake I made.
