sylph-decoder cb084e0a39 re: the primitive colour census -- and it refutes 38 of my own 80 forced verdicts
A disc-wide census of the ARGB that keyless elements carry.

Every full-screen *eff00* PRIMITIVE is pure black at its various alphas
(ff000000, 7f000000, 40000000, b2000000, cc000000, d4000000, 00000000). Black at
alpha a over content is exactly an alpha-over dim or fade, and an additive black
quad would be a no-op nobody would author -- so this narrows the open blend
question a long way. The only non-black primitive on the disc is pbafc.prm, RGB
00e8e0 cyan at alphas up to ff, and it is 844x600, NOT full-screen, so it sits
outside forced_backdrop's geometry guard. It is now the sole additive candidate.

The census also refutes my own argument for nearly half its verdicts. Of the 80
forced-first instances only 42 are .prm; 38 are .tbm carrying fade ffffffff. A
SOLID white quad at alpha 255 painted first would make the screen white, and no
screen is white -- so a .tbm is a white modulation on a texture, and element
alpha does not establish its coverage.

That is the .t32 error one file extension further out. I guarded that with
el.sprite.is_some(), which fixed the symptom and not the cause: an element's
alpha is not its texture's opacity, and only an untextured primitive makes the
two the same fact.

So 42 verdicts stay decoded and 38 drop to inferred -- still almost certainly
right, since all are named *base*, all are full-screen, and pfbase.tbm's first
position is measured in the running game, but that is a name-and-role argument
which this page elsewhere calls the weaker kind.

The code is deliberately unchanged. Restricting forced_backdrop to .prm would
send eleven screens' backgrounds back to u32::MAX -- last -- which is the
blank-screen bug the rule was written to fix. Downgrading the status is honest;
reverting the position would be wrong. The 42/38 split is pinned by a test so
anyone tightening the rule sees what it costs.

Separately, on the port's black_hold_units ask: four more no-input boots yielded
one usable log, which armed late and missed the publisher splash, so the sample
is still two runs spanning 3 and 4 frames. Their 6.5-9.2 range stands. And a
reason it may not be resolvable this way: the draw log DROPS frame numbers -- in
the 3-frame run, frames 121 and 124 are absent entirely, so "frames with no
sprite" and "span of frame numbers" are different quantities.

Their statistical correction is taken: at n=3 the sample SD (3.893) is the
estimator, not the population SD (3.179), making my run 1.88 sigma from the
corpus mean rather than 2.31.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
2026-08-29 21:51:06 +00:00

Sylpheed

A clean-room reverse engineering and port project for Project Sylpheed: Arc of Deception (Xbox 360, 2007).

Three things live here, in one repository so that a change spanning them lands as one commit:

The decoders crates/sylpheed-formats — the disc's formats, read and verified disc-wide
The port port/ — a Godot 4 project, plus crates/sylpheed-export which converts a disc into the open asset tree it reads
The corpus docs/re/ — what has been reverse engineered, with its evidence, its retractions and its dead ends

You need your own copy of the game. No game content is in this repository and none ever will be. The exporter reads the disc you supply.

The oracle is the real game

sylpheed-cli and the Explorer are tools for verifying our decoding. They are hypotheses under test and they have been wrong. When something must be checked against the truth, the truth is the game running in Xenia Canary, captured — not any renderer of ours.

This is stated first because getting it backwards is the most expensive mistake this project has made.

Layout

crates/
  sylpheed-formats/   the decoders. Disc-wide verified; the corpus is its spec
  sylpheed-cli/       headless tools -- render a screen, dump a table, probe audio
  sylpheed-viewer/    the Explorer: a human's window onto the disc. STATIC data only
  sylpheed-export/    disc -> the open, moddable asset tree
port/                 the Godot 4 project. Reads open formats ONLY
authored/             decisions that are NOT on the disc, each with its reason
data/
  base/               generated by the exporter. Gitignored, never hand-edited
  mods/               drop-in overrides. Yours
docs/
  re/                 the corpus: findings, refutations, method traps
  game/               how the game is navigated -- menus, modals, flight
  port/               the port's mission, its handoff contract, modding rules
  agents/             how the agent team works together
tools/                capture harnesses, probes, the share tool
exchange/             transient inter-agent files. NOT in git
docker/               the agent containers

Where to start

Xenia Canary is a separate repository: it is a fork tracking upstream, and it carries our instrumentation.

Conventions

Confidence is per claim, never per document: CONFIRMED · 🟡 PROBABLE · HYPOTHESIS · REFUTED. A withdrawn result is kept with its reasoning rather than deleted — that is why the numbers here can be trusted.

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