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2 Commits

Author SHA1 Message Date
Sylpheed RE agent
83d019515f re: confirm the cmesh<->model link via GameResourceID; world unit is oracle-blocked
Two follow-ups on yesterday's^Wthis morning's CollisionSet write-up.

1. The _cmesh <-> render-model link, which I recorded as UNTESTED because
   matching stems against .xbg object names covered 4 of 158.  The disc keeps
   only one build manifest, so that corpus was never going to answer it.  The
   right corpus is the GameResourceID field of the DefTables / GP_MAIN_GAME
   records -- 480 distinct values.  Against those, with a control that shuffles
   the characters of each stem:

       ship/mob stems prefixed by a real resource id   108/112 = 96.4%
       same stems, characters shuffled  (control)        0/112 =  0.0%
       asteroid stems prefixed (expected none)           0/46

   So a CollisionSet entry is <GameResourceID>[_<part>]_cmesh.  The 0/46 on
   asteroids matters as much as the 108/112: a test that fired on everything
   would be the bound-check hazard again.

2. The world unit.  Sweeping every pak for a name carrying a kilometre figure
   returns mapmesh_box_500km.col/.rgn and nothing else -- 162 references, all to
   that one pair.  The reading rests on a single filename with no corroborating
   instance anywhere in the data, so no static test can settle it; marking it
   blocked on the oracle rather than leaving it as an open static question.

   My objection's premise did survive: rou_e010 is a real GameResourceID and
   e010_ADAN_Attacker_S is in the stage tables, so the 133-unit mesh does belong
   to a craft the game calls an attacker.  Whether the trailing _S means "small"
   is a further guess (there are _EX4 / _HF / _HF_Wayne variants), so it stays
   suggestive rather than evidence.
2026-08-26 09:41:46 +00:00
Sylpheed RE agent
cc1f9e6734 re: decode CollisionSet_*.bin -- the per-object collision-mesh library
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.
2026-08-26 09:31:22 +00:00