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A framing correction from the human, and it runs through everything I have written, so it is a retraction rather than a silent edit. Reborn "was/is just a GUI explorer and extraction CLI for verifying the decoding of the various files. It may very well be wrong." The oracle is the Xenia Canary capture and the game. So verify-screen is a CONSISTENCY check between two decoders that share their assumptions, plus a regression detector -- not a correctness check, and agreement in it is not evidence of correctness. Its header now says so, it calls the CLI the COMPARISON renderer, and DIFFERS means "we moved apart, find out which of us moved". The uncomfortable part, recorded because it is the actual failure mode: this file already contained the sentence "two renderers reading one field through one decoder agreeing is not evidence that the field is right", written after the ptframe1 case -- and I then went on quoting 3/255 against sylpheed-cli as though it meant the port was right. Having the principle written down did not stop me leaning on the agreement. Three times both renderers agreed and both were wrong, each caught only by a capture: pteff05 (menu screens had no background), scale-0 (drawn full size instead of collapsed), rest() (the menu bracket missing). Correctness moves to the captures -- nine of them, indexed at docs/re/captures/ORACLE-CAPTURES.md, covering all five screens in scope. Three cautions travel with them: not gamma-neutral (there is a floor, don't chase it), geometry IS sound (a positional disagreement is real), and each is one moment of a still-animating screen. verify-screen keeps running over all 16 screens every iteration. It is still worth having -- total, cheap, and it catches a divergence introduced on the RE side. It is just not a grade.
76 lines
3.1 KiB
Markdown
76 lines
3.1 KiB
Markdown
# Sylpheed Godot
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A clean-room Godot 4 port of *Project Sylpheed: Arc of Deception*, starting with
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the menu shell: developer splash → intro video → title → main menu → submenus.
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**You need your own copy of the game.** Nothing in this repository is game
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content. An offline exporter reads the disc you supply and writes an open,
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moddable asset tree; the Godot project reads only that tree and never touches a
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disc format.
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```
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your disc ──▶ crates/sylpheed-export ──▶ export/ ──▶ port/ (Godot 4)
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(Rust; decoders come from JSON + PNG reads ONLY
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sylpheed-formats) + OGG + OGV open formats
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```
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## Why the wall
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Two reasons, and the second is the interesting one:
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1. Godot cannot read IPFB archives, RATC bundles, T8aD textures, XMA banks or
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WMV video, and it should not learn to.
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2. **Modding is a goal of this port.** If the runtime reads the original formats,
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modding means reverse engineering. If it reads JSON and PNG, modding means
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opening a file.
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## Where the knowledge comes from
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The decoders live in [`sylpheed-formats`][formats], pinned by revision — a
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separate project, where the reverse engineering happens. Its
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`docs/port/HANDOFF.md` is the contract: what has been decoded, what was measured
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off the running game, and what is known to be undecodable. Read it before
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assuming a value is on the disc.
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[formats]: https://git.mc02.dev/fabi/Syplheed-Reborn
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## Layout
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| `crates/sylpheed-export/` | disc → open formats. Regenerates `export/` wholesale |
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| `port/` | the Godot 4 project |
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| `authored/` | decisions that are **not** on the disc, each with its reason |
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| `export/` | generated, gitignored, never hand-edited |
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| `tools/` | verification harnesses that hold the port to the reference renderer |
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| `docs/` | the mission, the format spec, the agent's loop prompt |
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## Verifying
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**The oracle is the Xenia Canary capture and the game**, not either renderer.
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`sylpheed-cli screen render` is an explorer and extraction CLI for verifying
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decodes, and it can be wrong -- three times both it and the port agreed and both
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were wrong, each caught only by a capture.
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So `tools/verify-screen` is a **consistency check and a regression detector**,
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not a grade. It draws every exported screen both ways -- built from the same
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`sylpheed-formats` revision the exporter is pinned to -- and reports the largest
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per-channel difference in the frame:
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```
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tools/verify-screen # every screen in the manifest
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tools/verify-screen main_menu # one of them
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```
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A difference means the two moved apart; `docs/DECISIONS.md` says which one moved
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and why, rather than tuning the port until the number goes down. Correctness is
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checked against the captures indexed at `docs/re/captures/ORACLE-CAPTURES.md` --
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mind that they are not gamma-neutral, so RMSE against them has a floor.
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## Status
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**P1.** The exporter writes `GP_TITLE`'s twelve screen builds and their sprites,
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and the Godot project draws any of them statically at 1280x720 from that tree
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alone. `main_menu` matches the reference renderer to within 3/255 on every
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channel of every pixel. Next: P2, keyframe animation.
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