Files
Sylpheed/godot-import/README.md
MechaCat02 f44ebced59 merge the Godot port's history into the monorepo
Brought in with a subtree merge rather than a copy, so the port's 31 commits
survive as history rather than arriving as one anonymous import. Landed under
godot-import/ and moved into the final layout in the next commit, which keeps
git's rename detection able to follow each file across the move.
2026-08-29 11:32:01 +02:00

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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:

  1. Godot cannot read IPFB archives, RATC bundles, T8aD textures, XMA banks or WMV video, and it should not learn to.
  2. 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

The oracle is the Xenia Canary capture and the game, not either renderer. sylpheed-cli screen render is an explorer and extraction CLI for verifying decodes, and it can be wrong -- three times both it and the port agreed and both were wrong, each caught only by a capture.

So tools/verify-screen is a consistency check and a regression detector, not a grade. It draws every exported screen both ways -- built from the same sylpheed-formats revision the exporter is pinned to -- 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

A difference means the two moved apart; docs/DECISIONS.md says which one moved and why, rather than tuning the port until the number goes down. Correctness is checked against the captures indexed at docs/re/captures/ORACLE-CAPTURES.md -- mind that they are not gamma-neutral, so RMSE against them has a floor.

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.