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P3. The exit is the group playing ITSELF out, not a black rect over a frozen screen -- and that was settled by a test that discriminates rather than by plausibility. Under the black-rect model every region is scaled by the same 1-alpha, so the button/background brightness RATIO would hold constant through the fade; measured, it falls 6.495 -> 5.574 -> 3.105 -> 2.125 -> 1.935. Implemented by giving the final untimed keyframe a SYNTHETIC time, exit_ramp_units after the last timed one, then interpolating it like any other frame. One code path: arriving and leaving differ only in how far `t` is allowed to run, not in kind. `holding` is what the sequencer clears to send a screen away. The sequencer waits on nothing the disc does not carry. A screen holds until its own group has arrived, then plays out; `dwell` in flow.json is deliberately empty because each screen's dwell IS its keyframe group (publisher wordmark 3.92 s, developer logos 3.17 s, both read from the disc). Any extra hold would be a number nobody measured. The last screen keeps holding -- nothing is taking the title's place, and a boot that ends by fading to black looks like a boot that crashed. flow.json reproduces an OBSERVATION and says so in its header: Q6 closed with a negative, the order is on the disc nowhere, a transition is a call with a name argument chosen by code. The intro video's place in the real boot is named as a gap rather than the order being quietly rewritten to hide it.
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.