sylph-decoder 47faeaa7a9 re: RETRACT "the game never draws eff3" -- a batched draw merged two quads
The console draws all five title flashes. My claim that ptlogo_back2eff3 is
never drawn was an instrument artefact, and I had reported it to the port with
three alternative explanations "ruled out".

A GPU draw can batch several quads -- indices=4 is one, indices=8 two,
indices=24 six -- and the UI draw log dumps only the first 8 vertices. Taking
min/max over a line's whole vertex list merges quads into one box.

eff3 is batched with eff4, and because the wipe family is right-aligned, eff3
(788..1196) lies ENTIRELY INSIDE eff4 (447..1196). The union is exactly eff4's
own extent, so the merged box matched eff4 to 1 px, eff3 vanished, and nothing
looked wrong.

Parsed per quad, all five fire in both title entries in the declared stagger:
eff1 130-131, eff2 133, eff3 133-134, eff4 133-135, eff/eff5 134+, back2 136+;
and 5953-5955 / 5955-5957 / 5957-5958 / 5957-5959 / 5958+ / 5962+ in entry 2.
Frames 133 and 134 are t=60.1 and 62.3, inside eff3's declared t in (58,64).

Also retracts "the developer splash is one composited quad" -- the same bug,
which the port refuted by arithmetic first (a 259-tall box cannot contain three
logos spanning y 164..585). It draws three logos and three glows as separate
quads in one indices=24 call; the 525x259 was gamearts_eff merged with
seta_eff. The 9-unit black hold is unaffected: those glows are the developer
splash's first draw.

The three "ruled out" explanations were all aimed at the wrong failure. In
particular the invisible-draw check counted draws with NO geometry line, when
the hiding place was draws with PARTIAL geometry. Refuting three wrong
hypotheses is not evidence for a fourth, and a list of failure modes written by
whoever built the instrument is the least likely to contain its blind spot.
Recorded in METHOD.md, along with the tell that was present and explained away:
a merged box carries the first quad's colour, which made one element's alpha
read 255/127/254 on consecutive frames.

New tool: tools/re-capture/quads_per_frame.py parses vertices in groups of four
and warns when the logged quad count falls short of indices/4.

Also guards a double-A-tap in ui_draw_capture.sh: the movie branch ignored that
TARGET=menu had already tapped, so a run tapped A on the title at t=23s and
again at t=27s on the transition; the guest faulted and Xenia dumped registers
to stdout until the file reached 519 MB.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
2026-08-29 20:49:27 +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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