Syplheed-Reborn/docs/re/SESSION-2026-08-11.md

Session log — 2026-08-11 (autonomous run)

What changed today, in the order a reviewer would want it, with the one item that needs your decision called out first.

Needs a decision from you

Editing save slot 01. Save files can now be written back (savegame_edit.py re-wraps a real save byte-identically), and hand-written saves load. That unblocked several questions by probing throwaway slots. But the title-menu screens read the auto-save (slot 01), so the remaining save-field questions (the difficulty enum, SHAB.b) need slot 01 itself edited — the only save with real progress. Not done. Recoverable (full content backup + slot 01's bytes archived), but it is your call. Everything else below was done in throwaway slots.

Findings, by area

Save format

• The develop differential: buying one Arsenal weapon moves exactly three fields — Points +24 (which separates it from +28), clear ratio +8 (so the ratio counts collection, not stages), and two entries of the 54-byte blob. Blob alphabet: 0 locked / 2 developable / 4 owned; only the 4s are stored, 2 is re-derived at load.
• The blob's index space is solved — it follows strings.tbl's item order, cut items included, pinned by four probe saves and closing exactly at 53.
• SHAB is the per-stage record table: record 0 = Stage 01, and c is its best clear time in ms (324773 = the 05:24.77 MISSION SELECT shows).
• Refuted: every GHAD scalar as stage/difficulty (16 elements probed), and "stage = filled SHAB count + 1".

Formats

• T8aD 96 % → 100 % of the disc: a surface is a list of sub-rectangles (dst X, dst Y, w, h per rectangle), not a 256 grid. The "~15 % variants" were a wrong model.
• LSTA: the count was never unreliable — it counts sprites and PRMD primitives (64/64 exact).
• RATC: "one level deep" is not a limitation; nested records are leaves that reference siblings by name (10 144/10 148 resolve).
• UI screens are fully reconstructible from their bundle — element list + order (declaration table, with a parent index) and placement/animation (keyframe region). Validated against the running game to ±2 px.
• Movie ↔ subtitle ↔ voice link solved statically (101 movies) — INDEX had it filed as needing the running game.
• XPR2 channel order confirmed against the game (hue 23.3° vs 9.3°).

Meshes — the user-reported viewer bug

• Root-caused, after one wrong turn I corrected in place: the giant slab on e106 is not a stray volume but an XBG7 mis-decode — the same resource is a 49×23×42 turret in 11 containers and 1600×2100×4800 in 3.
• New detector: a resource shared across containers must decode to the same bounds. 125 of 681 shared resources fail that check — a measured lower bound on silent mis-decodes (distinct from the 814 honest declines).

Two disc defects found

SUBTITLE_S12B.tbl (referenced by the movie table, present in no language) and pmbase.t32 (placed by pmbase.rat, present nowhere). A reimplementation should skip a missing asset rather than treat it as a decode failure.

Process notes worth keeping

• Several "the data is inconsistent" comments meant our model was incomplete (T8aD variants, the LSTA count). Re-test such notes rather than routing around them.
• A test that walks the oracle's items and looks each up in our output can only fail one way — it never sees extras. That shape hid the ship bug and, earlier, include_external.
• When a diagnosis has eliminated every hypothesis and the last step is a visual, do the visual first. Three iterations went by before a 30-second render showed it.