Five items, written down here rather than only in a message, because a request that lives in one conversation dies with the container. Two are blocking P3 (how to recognise the splash bundle, and what the ~0.4 s fade-out actually measures), one is cheap and prevents P5 rework (focus drawn over vs instead of the base -- the port picked replace without evidence, and the oracle says it picked wrong), one needs a joint decision rather than a unilateral one (whether the port should draw the newly-decoded rotation and thereby become deliberately more correct than the renderer it verifies against), and one calibrates whether RMSE against captures has a floor at all.
Sylpheed Godot
A clean-room Godot 4 port of Project Sylpheed: Arc of Deception, starting with the menu shell: developer splash → intro video → title → main menu → submenus.
You need your own copy of the game. Nothing in this repository is game content. An offline exporter reads the disc you supply and writes an open, moddable asset tree; the Godot project reads only that tree and never touches a disc format.
your disc ──▶ crates/sylpheed-export ──▶ export/ ──▶ port/ (Godot 4)
(Rust; decoders come from JSON + PNG reads ONLY
sylpheed-formats) + OGG + OGV open formats
Why the wall
Two reasons, and the second is the interesting one:
- Godot cannot read IPFB archives, RATC bundles, T8aD textures, XMA banks or WMV video, and it should not learn to.
- Modding is a goal of this port. If the runtime reads the original formats, modding means reverse engineering. If it reads JSON and PNG, modding means opening a file.
Where the knowledge comes from
The decoders live in sylpheed-formats, pinned by revision — a
separate project, where the reverse engineering happens. Its
docs/port/HANDOFF.md is the contract: what has been decoded, what was measured
off the running game, and what is known to be undecodable. Read it before
assuming a value is on the disc.
Layout
crates/sylpheed-export/ |
disc → open formats. Regenerates export/ wholesale |
port/ |
the Godot 4 project |
authored/ |
decisions that are not on the disc, each with its reason |
export/ |
generated, gitignored, never hand-edited |
tools/ |
verification harnesses that hold the port to the reference renderer |
docs/ |
the mission, the format spec, the agent's loop prompt |
Verifying
sylpheed-cli screen render -- built from the same sylpheed-formats revision
the exporter is pinned to -- is the reference renderer. tools/verify-screen
draws every exported screen both ways and reports the largest per-channel
difference in the frame:
tools/verify-screen # every screen in the manifest
tools/verify-screen main_menu # one of them
Where the two disagree, one of them is wrong; docs/DECISIONS.md says which and
why, rather than tuning the port until the number goes down.
Status
P1. The exporter writes GP_TITLE's twelve screen builds and their sprites,
and the Godot project draws any of them statically at 1280x720 from that tree
alone. main_menu matches the reference renderer to within 3/255 on every
channel of every pixel. Next: P2, keyframe animation.