# Primary objective — a playable menu shell in Godot **Status:** active, set 2026-08-28. This supersedes "work the RE backlog" as the agent's primary objective. Reverse engineering continues, but it is now *in service of* this goal: an item earns attention because the port needs it. ## What we are building A Godot 4 project that boots to an interactive main menu using the player's own disc, through the sequence the real game uses: ``` developer logo splash → intro video → title / PRESS Ⓐ → main menu → submenus ``` No gameplay. No 3D. No emulator. The success condition is a human pressing a d-pad and Ⓐ and moving through those screens with the right art, the right animation, the right music and the right transitions. **Ready Room is a gated stretch goal.** See §6 — do the probe first, then stop and report rather than committing to it. ## 1. The two halves, and the wall between them The Godot project **never reads a disc format**. It reads only open formats. The conversion happens offline, in Rust, and the wall between the two is the point: ``` disc ──▶ crates/sylpheed-export ──▶ export/ ──▶ port/ (Godot 4) (Rust, uses sylpheed-formats) JSON + PNG + OGG reads ONLY + Ogg Theora open formats ``` * **No GDExtension. No Rust in the Godot project.** If Godot needs something it cannot read, the exporter's job is to emit it in a form Godot can, not to bridge the two runtimes. * **`crates/sylpheed-viewer` is not involved.** The Explorer is the human's tool for exploring and verifying the RE work. It stays Rust/Bevy, it keeps its static-data rule, and it is neither a dependency of nor a dependent on the port. Do not refactor it "to share code with" the port. * `sylpheed-formats` is shared, because it is the decoder and there must be one. ## 2. The format is a deliverable, not a dump The second goal of this port is **modding**. That makes the exported layout part of the product, not a temp directory: * **JSON, not XML.** Godot parses JSON natively with `JSON.parse_string`; its `XMLParser` is a SAX-style API that would need a hand-written binding for every schema. JSON is also what every external tool a modder might reach for already speaks. * **Names, never hashes.** A file is `screens/title/main_menu.json`, not `0x90822a39.json`. Where the disc's own name was never recovered — the six `*2D` archives and `GP_READY_ROOM`, see [the atlas](../re/disc-atlas.html) — emit a stable synthetic id **and record in the file that the real name is unknown**. A modder must be able to tell a recovered name from one we invented. * **A tree that means something.** `screens/`, `sprites/`, `audio/music/`, `audio/sfx/`, `video/`, `text//` — organised by what a person is looking for, not by which archive it came out of. * **Provenance in every generated file.** Source archive, entry index, and the exporter version. This is what keeps the export auditable against the disc instead of drifting into an unverifiable fork. The schema lives in [FORMAT.md](FORMAT.md) and is **versioned**. Changing it is a deliberate act with a version bump, not a silent edit. ## 3. Derived vs authored — keep these apart This is the discipline that matters most, and it is the corpus's own rule applied to a new artefact. | | `export/` | `authored/` | |---|---|---| | produced by | running the exporter | a human or the agent, by hand | | contains | what the disc says | what we decided | | edited by hand | **never** | always | | committed to git | **no** (see §4) | yes | | when regenerated | overwritten wholesale | untouched | Some things this milestone needs are **not on the disc in any form we have decoded**, and they must live in `authored/` with a stated reason: * **Which button does what.** `ptbtn01…05` are sprites with baked-in labels. A human can read "NEW GAME" off the image; there is no field that says so. The mapping button → GamePart id is an authored guess until code says otherwise. * **Paint order.** Solved at runtime, unsolved from the file — the declaration table is provably not it. For these six screens, author the z-order and mark it authored. Do **not** let a hand-tuned order leak into `export/` and later get mistaken for a disc fact. * **Sound-cue bindings.** Which cue fires on move / confirm / back. Every `authored/` entry carries a `why` field. When a later iteration decodes the real answer, the authored entry is deleted and the exporter emits it instead — and that transition is the measure of progress. ## 4. Do not commit game assets `export/` is generated from the user's own disc and **must be gitignored**. The repository stays a clean-room port: code, schemas, authored mappings and documentation. Anyone building it supplies their own disc. If you find yourself committing a PNG of a game sprite or a transcoded video, stop. ## 5. Milestones, each with a gate Do these in order. A milestone is done when its **artifact** exists, not when the code compiles. | | Milestone | Gate (the artifact) | |---|---|---| | **P0** | Exporter skeleton; one screen and its sprites to `export/` | `export/screens/title/main_menu.json` validates against FORMAT.md, and the PNGs open | | **P1** | Godot renders that screen statically at 1280×720 | A screenshot from Godot beside `sylpheed-cli screen render` of the same build — they should agree | | **P2** | Keyframe animation | The main menu's buttons slide in. **Measure the time unit first** (§7) | | **P3** | Splash → title, with the transition | Godot runs the two screens back to back unattended | | **P4** | Intro video | `ADV.wmv` plays in Godot with audio (§7) | | **P5** | Main menu: d-pad navigation, focus states, Ⓐ into a submenu, B back | A human clicks through it | | **P6** | Audio — menu BGM and move/confirm SFX | Sound on the gate in P5 | | **P7** | New-game intro video after NEW GAME | Plays, then returns to a defined state | | **S1** | *Gated* — Ready Room. Run the probe in §6 and **stop** | A written go / no-go | ## 6. The Ready Room probe — do this early, it is one iteration `GP_READY_ROOM.pak` is the largest UI archive on the disc, 1 106 entries, and only **6 of its names resolve**. It is also ISL-scripted. That could mean a week or a quarter, and one cheap test tells you which. **The probe:** our screen catalog enumerates bundles by **content**, not by name — `is_build` / `is_composable` read the bytes. Unrecoverable *paths* therefore do not necessarily mean unrenderable *screens*. ```bash sylpheed-cli screen list "$SYLPHEED_DISC/dat/GP_READY_ROOM.pak" sylpheed-cli screen render --build "$SYLPHEED_DISC/dat/GP_READY_ROOM.pak" /tmp/rr.png ``` Report: how many builds it finds, whether any composite looks like a Ready Room, and whether the screens are 2D at all or whether the room is 3D with a UI overlay — because if it is 3D, this milestone is out of scope by definition and the answer is no-go, not "try harder". **Then stop and write the go/no-go.** Do not start Ready Room work on your own authority. ## 7. Two decisions already made, and one measurement owed **Video: transcode to Ogg Theora.** `ADV.wmv` is WMV3 video with WMA Pro audio, 1280×720 at 30 fps, 137 s. Godot 4 plays only Ogg Theora natively. Transcode with ffmpeg and **keep the exact command in the exporter's config** so it can be re-run with different settings. Theora at 720p is not great; if the result is visibly poor, say so and propose the FFmpeg-GDExtension fallback — do not silently adopt a dependency. Only `ADV.wmv` and the one new-game intro are in scope; the disc holds 3.3 GB of video and transcoding all of it is not this milestone. **Screens: `GP_TITLE.pak` is the whole title-side tree.** Build 4 is the title with the animating wordmarks, build 5 the five-button main menu, builds 6/8/9 are submenus, and the developer splash is the `palogo` bundle in the same archive. Buttons are identifiable as data: element kind `0x3002`, ordered top-to-bottom by resting Y, each paired with an `f`-suffixed highlighted variant. You do **not** need the undecoded navigation graph to make a vertical menu work. **The measurement owed: what is a keyframe time?** Values run 16…269 on the title build. 60 Hz frames would make the title intro ~4.5 s, which is plausible and untested. Settle it against a capture before building animation on it — this is exactly the kind of number that silently poisons everything downstream. [`ui-resting-pose.md`](../re/structures/ui-resting-pose.md) already establishes that a keyframe is the **start of a ramp**, not a pose that is held. ## 8. What is explicitly out of scope 3D, gameplay, HUD, missions, the emulator, save/load, localisation beyond English, and any archive outside `GP_TITLE`, `tables.pak`, `sound.pak` and `dat/movie/` — except for the Ready Room probe in §6.