sylph-decoder ae42f7f850 re: the paint-order tie-break costs the port zero pixels, not 24 pairs
The census bounded WHERE a wrong tie-break could show and said outright that
nobody had measured how many of those pairs change a pixel. Measured.

`compose_with_order` renders a bundle in a caller-supplied order; the new
example renders each screen twice, once derived and once with one tied pair
swapped, and diffs. Same-key elements are contiguous under a stable sort on
(key, i), so a swap paints nothing else in between.

Controlled per entry: swapping an OVERLAPPING pair with DIFFERENT keys moves
36 305 to 771 479 px (max delta 254). Where no such pair is drawn the output
says so rather than reporting an uninterpretable zero.

* EXTRAS (entries 6/9) and the main menu (5/8): 0 px. The tied ptframe pairs
  ink ~3 600 px each and share NONE of them -- the 102x132 rect overlap was an
  artefact of approximating an element as pivot x 2. Blend-independent.
* Across all 31 drawable overlapping tied pairs in GP_TITLE, the largest change
  any of them makes to any channel is 3/255.
* Withdrawn: "a wrong tie-break can be wrong by a whole layer". That rested on
  ptlogo_back2eff5 geometrically containing two other glows. Rendered, the swap
  moves 6 390 px by max delta 2. Containment is not occlusion when the container
  is a near-transparent glow, and nobody had rendered it before asserting it.

Reach: this measures our compositor's sensitivity to order, not the game's. The
zero-shared-ink results hold under any per-pixel blend; the delta<=3 figures
assume ours.

13 disc-gated ui_paint_order_disc tests and 114 lib tests pass unchanged.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
2026-08-29 14:47:19 +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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