Sylpheed port agent 3d12498550 port: Godot draws an exported screen at its resting pose
P1. The project reads only `export/` -- the manifest, a screen's JSON and its
PNGs -- and draws every element at `rest`, in the export's own `paint_order`.

Three choices worth the words:

* `ExportTree` addresses screens by manifest NAME, never by path, and checks
  `format` on the manifest and on each screen before drawing. Textures are
  decoded from bytes at runtime rather than Godot-imported: `export/` is
  gitignored and regenerated wholesale, and a `.import` per sprite would be
  derived state next to derived state, invalidated on every re-export.

* One CanvasItem draws the whole screen. `paint_order` is already back-to-front,
  so honouring it is a loop; spreading it across sixteen nodes' z-indices would
  hide the one unresolved thing about that order -- the ties -- behind Godot's
  sibling rules.

* The screen renders into a SubViewport sized to the export's `design` rect.
  Capturing the window instead gave 1280x720 of screen minus a window manager's
  title bar: 1235x695. A gate that rescales that to compare against a 1280x720
  composite is measuring the compositor.

Nearest-neighbour filtering, because the export is a 1:1 copy of the disc's
texels, elements draw at up to 500 %, and it is what `ui_layout::blit` does --
so a filter difference cannot masquerade as a placement difference in the diff.

No keyframe interpolation and no focus state: both depend on constants that are
MEASURED rather than decoded (HANDOFF Q1, Q5), and a pixel-diff gate must not
have one of those inside it. P2 and P5.
2026-08-28 19:31:03 +00:00

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
docs/ the mission, the format spec, the agent's loop prompt

Status

Pre-P0. Nothing runs yet.

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