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re: the 8 values per asteroid are index, quaternion, position

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Measured over every Frame_*Asteroid* record on the disc - 384 records, 37518
items (6253 per language pack x 6; the remaining 380 per pack belong to the
seven record-less Alpha frames, the same 57-vs-64 split as before).

  slot 0    equals the running index 0..N-1   37518 / 37518, max 587, and the
            largest FrameCount is 588, so the last index is N-1
  slots 1-4 a unit quaternion                 37518 / 37518 within 1e-4 of 1.0
            (min 0.999999, max 1.000001)
  slot 4    sign of the real part             min +0.001, never negative -
            canonical w-last, so the order is (x, y, z, w)
  slots 5-7 position in metres                -163858..+79572, -114308..+76422,
            -105224..+110263 - inside the +/-250 km half-extent of
            mapmesh_box_500km

len(anonymous fields) == 8 * FrameCount on 384 of 384, zero mismatches.

The unit-norm test is the control: an arbitrary 4-tuple has no reason to sit on
the unit sphere and every one of the 37518 does. Two further cross-checks fell
out - the maximum index is exactly max(FrameCount) - 1, and every position lies
inside the 500 km box the corpus already knows (world unit = 1 metre).

There is no scale slot: an asteroid's size comes from its group's
AsteroidModelName, which is why a group is one model plus one placement list.

Not settled: whether the quaternion is object->world or world->object and its
handedness - a norm test cannot separate those; and why S28_p1 has an asteroid
volume with no definition.

All fifteen artefacts byte-identical.
This commit is contained in:
Sylpheed RE agent
2026-08-28 02:03:23 +00:00
parent 863a88dbf3
commit 1f0f90e304
3 changed files with 63 additions and 3 deletions
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docs/re/INDEX.md
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@@ -119,7 +119,7 @@ files, which is how the same ground got covered twice.
| [`structures/isl-message-dialogue-link.md`](structures/isl-message-dialogue-link.md) | Mission scripts as dialogue — built-in 64 -> message id -> caption text | ✅ CONFIRMED total, 2 683/2 683 call sites across all 28 stages resolve, no residue |
| [`structures/mission-objective-counter.md`](structures/mission-objective-counter.md) | `REMAINING OB` — the mission's own objective counter, in RAM | ✅ CONFIRMED for one Stage 02 run: a big-endian u32 whose value |
| [`structures/movie-subtitles.md`](structures/movie-subtitles.md) | Movie subtitles & the movie ↔ mission ↔ text chain | — |
| [`structures/asteroid-fields.md`](structures/asteroid-fields.md) | `AsteroidGroup_00N` — the asteroid-field tables a `Phase_N.AsteroidDefinition` names | ✅ 10 objects/pack, 384 group records, 3 fields each (`AsteroidModelName`, `AsteroidFrameName`, `EnumAsteroid` = **the frame record's `FrameCount`, 57/57**, and the frame holds 8 anonymous values per asteroid); `Enum<Thing>` counts while `Enumerate<Thing>` names a table (54/60); the join resolves as `name_hash("stage\" + name)` 9/9; 🔑 a tenth `Frame_Alpha_S01_*` object nothing references — it miscounts AND its 7 frames have no placement records; 🔑 **S28_p1 has an asteroid volume but no definition** |
| [`structures/asteroid-fields.md`](structures/asteroid-fields.md) | `AsteroidGroup_00N` — the asteroid-field tables a `Phase_N.AsteroidDefinition` names | ✅ 10 objects/pack, 384 group records, 3 fields each (`AsteroidModelName`, `AsteroidFrameName`, `EnumAsteroid` = **the frame record's `FrameCount`, 57/57**, and the frame holds **`index, quaternion(x,y,z,w), position(x,y,z)`** per asteroid — 37 518 items, unit norm 37 518/37 518); `Enum<Thing>` counts while `Enumerate<Thing>` names a table (54/60); the join resolves as `name_hash("stage\" + name)` 9/9; 🔑 a tenth `Frame_Alpha_S01_*` object nothing references — it miscounts AND its 7 frames have no placement records; 🔑 **S28_p1 has an asteroid volume but no definition** |
| [`structures/mcol-collision.md`](structures/mcol-collision.md) | `MCOL` — same container and map parameters as `REGN` | 🟡 OPENED — `POF0` at `data_size+16` 11/11, bbox pad words 11/11, `extent == max−min` 11/11, and bbox + cell-size distributions identical to `REGN` (2/6/3 and 2/9); everything past `0x40` ❔ |
| [`structures/regn-map-grid.md`](structures/regn-map-grid.md) | `REGN` — a per-map spatial grid (and `MCOL` beside it) | ✅ CONFIRMED for the header, which self-checks on all 11 objects on |
| [`structures/savegame-format.md`](structures/savegame-format.md) | Save file (`savedata`) — container ✅ exact, 3 fields named ✅, rest ❔ (2026-08-11) | ✅ CONFIRMED for the container and the chunk layout — parsed off the |