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P2. A keyframe is the start of a linear ramp toward the next; `ScreenView` walks them at `time_units` and `boot.gd` advances that in real time, or freezes it with `--time=<seconds>`. `authored/timing.json` holds the ONE constant this needs. HANDOFF Q1 is answered -- linear, 2 units per rendered frame, 1 unit = 1/60 s -- but that conversion was MEASURED off the running game, not read from a file, so it is authored rather than exported and it says so at length. Expressed as units-per-second, because 60 is exact and 0.01666... is a decimal a reader has to recognise. The timeline stops at the last TIMED keyframe and never plays the exit. Every group's final keyframe carries no `t` -- across this export it is a fade-out for 116 of 134 elements, a scale-and-slide exit for 12, and identical for 6 -- so playing into it would mean inventing how long the ramp takes. That duration is the screen transition, it is measured at ~0.4 s, and it is P3's to author with its own evidence. `exit_ramp_seconds` is therefore null on purpose, not missing. `--pose=rest` keeps the P1 behaviour available: since the port's default is now the timeline and the two DISAGREE, renderer-vs-renderer diffing has to be able to ask for the same assumption the reference renderer makes. The interpolation is checked by where it lands: on 8 of the 12 screens the settled timeline is byte-identical to the rest render.
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.