dfb768270a
The Decoder's R2 note: alpha peaks at 80 of 255, so the composite difference is a small signal either way and the expected magnitude should be set before the test. Committed here before any capture exists. Rendering the same pose at peak alpha under both composites: 25 015 px footprint, mean |additive - alpha-over| 16.92 levels inside it, max 50, RMS over the whole frame 3.746. My first prediction was wrong and that is the useful part. The composites differ by exactly alpha*bg, which with mean background 94.78 predicts 29.73 levels. Measured 16.92. The formula uses the keyframe alpha and ignores that the sprite carries its own per-pixel alpha channel modulating it -- implied mean sprite alpha about 145/255. Caught only because the prediction was written down and disagreed with the render. The pre-registered test: additive is brighter than alpha-over at every footprint pixel in one direction, so the discriminator is regional SIGN over 25 015 pixels, not per-pixel magnitude. If the game is additive, rendering alpha-over must leave the footprint about 17 levels darker than the capture relative to the surrounding frame, and additive must leave no such regional bias. Neither bias refutes both and points at the ramp or the pose instead. Feasibility stated before asking for a run: as a whole-frame RMSE the difference is 3.746, below the title's own +/-5.56 capture-phase term, so verify-capture's headline number could not settle this even at peak alpha. It is discriminable only as a signed regional statistic.
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-cliand 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
-- and RUNNING.md, which is how you actually start it
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
docs/re/INDEX.md— what is decodeddocs/re/REFUTED.md— what has been tested and dieddocs/re/METHOD.md— traps this project has already paid fordocs/game/navigation.md— how the game is navigateddocs/port/MODDING.md— why the asset tree looks the way it does
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.