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Syplheed-Reborn/docs/re/structures/ui-rat-layout.md
Claude (auto-RE) f65387143e re: the UI screen gap is closed -- the bundle also carries every element's placement
Immediately after the declaration table the RATC bundle holds a placement region,
one group per element: a header of (u32 element index, u32 keyframe count)
followed by that many 40-byte keyframes carrying scale/tint/X/Y. The element
index is stated in the header, so the correspondence is read, not inferred from
order.

Tutorial pause bundle: 11 groups for 11 elements, every header index and count
matching the blocks present. The values are self-evidently right -- three menu
buttons at X=546 exactly 70 px apart (288/358/428), title (540,119), message
(451,545), and the eff* sprites carrying multi-position fly-ins.

Cross-checked: pgp_ttrl_btn10.rat places its own sprite at (546,288), identical
to its inline group, so the inline region is the same placement data and it
covers the eff*/deli*/msg elements that have no record of their own.

So a screen is fully reconstructible from its bundle alone: element list and
order from the declaration table, placement and animation from this region,
plus the sprites, with "opt " supplying focused states. This retires the caveat
added earlier today that only the order was known.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-11 21:58:21 +00:00

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# `.rat` — the UI element layout / animation record
**Status:**`CONFIRMED` for placement (2026-07-28). The retail UI can be
**reassembled from the disc**: the tutorial PAUSE menu rebuilds pixel-accurately from its
sprites placed at the coordinates in their `.rat` records — no fitting, no manual nudging.
![real vs rebuilt](captures/ui-layout/pause-tutorial-real-vs-rebuilt.png)
*Left: the running game (Canary screenshot). Right: rebuilt from `GP_PAUSE_MENU.pak` alone.
The remaining differences are the animated frame/glow sprites (`*eff*`) that were not
placed, and the live 3D background.*
## Screen composition
The UI is **one pak per screen**`GP_TITLE`, `GP_PAUSE_MENU`, `GP_READY_ROOM`,
`GP_SAVE_LOAD`, `GP_MISSION_SELECT`, `GP_OPTIONS`, `GP_SYSTEM`, `GP_TUTORIAL`,
`GP_STAGE_CLEAR`, `GP_MOVIE_THEATER`, `GP_DEBRIEFING_PILOTLOG`, `GP_LEADERBOARD`,
`GP_MISSION_LOG`, `GP_BUNK`, `GP_DIALOG`, `GP_GAMEOVER`, `GP_CHALLENGE`,
`GP_HANGAR_ARSENAL`.
Inside a screen pak, each top-level [RATC](../INDEX.md) bundle is **one (context × language)
build of that screen**. Its own header is the screen's **element declaration table**, and
the elements themselves follow as children:
| child | what it is |
|---|---|
| `<name>.t32` | the sprite ([T8aD](texture-color-k8888.md)) |
| `<name>.rat` | that sprite's **layout record** (this document) |
| `<screen>loop1.rat` | a looping sprite animation (see below) |
### The bundle header — element declaration table
```
0x14 u32 entry count
0x20 entry[count], 60 bytes each:
+0 char[28] element name, NUL-padded ("pgp_ttrl_eff10.t32", "pgp_ttrl_btn10.rat")
+28 u32 0 on every entry seen
+32 u32 PARENT element index, or 0xffffffff for "none" ← see below
+36 u32 0xffffffff on every entry seen
+40 u32 kind flags 0 for a plain sprite, 0x3002 for a button record,
1 for an element that has a parent
+44 u32 0xffffffff, but 0 on button records
+48 u32 pivot X
+52 u32 pivot Y
+56 u32 0
```
**Corrected 2026-08-11:** this was previously written as "`+28` u32 ×4 flags" — it
is **five** words, and the second of them is not a flag.
**`+32` is a parent element index.** In the in-mission pause bundle,
`pgpeff02a.t32` carries `3` and element 3 is `pgpeff02.t32`; `pgpeff03a.t32`
carries `5` and element 5 is `pgpeff03.t32` — each `…a` variant naming its base
element. Verified on two independent language builds of that screen (4 links, no
out-of-range value anywhere in any bundle), and the tutorial bundle, which has no
`…a` variants, carries `0xffffffff` throughout.
The table lists **both** sprites and `.rat` records — it is the screen's element list.
`pgp_ttrl` declares 11: six `eff*`, `msg`, and four `.rat`s (`title`, `btn10..12`).
**Verified:** for all 7 `.t32` entries the declared pivot is *exactly* half the decoded
texture's dimensions — `eff10` 408×120 → 204,60; `eff21` 428×360 → 214,180; `msg` 381×38 →
190,19; and so on, 7/7 with no mismatch (`tools/re-capture/ratc_decls.py`).
`GP_PAUSE_MENU.pak`'s six bundles are `{in-mission, tutorial} × {English, Japanese}`, with
the two in-mission builds each present twice at identical size. The purpose of that
duplicate is **NEEDS-HUMAN** (resolution or aspect variant?), and where the other four
shipped languages live is likewise unresolved — this pak holds only EN and JP.
Naming is transparent: `pgp` = pause screen, `pgp_ttrl_` = its tutorial context, `btnNN` =
menu item, `btnNNf` = that item's **focused** sprite, `eff*` = frame/glow decoration,
`deli*` = the item divider, `title`, `msg`.
## Record layout
Big-endian u32 throughout (Xbox 360), and **tag-driven**: 4-char ASCII tags (`opt `,
`PRMD`, `end `) mark sections, so a record is a stream of blocks rather than a fixed struct.
A minimal record (a static button) is 165 bytes:
```
0x00 "RATC" magic — a RATC bundle reused as a data record
0x08 u32 payload size
0x14 u32 entry count (loop1.rat: 3, matching its 3 sprite names)
0x18 u32 design width = 1280
0x1c u32 design height = 720
0x20 char[16] the sprite this record places, e.g. "pgpbtn00.t32"
0x50 u32 pivot X = texture width / 2
0x54 u32 pivot Y = texture height / 2
...
── placement block ──
u32 scale X = 100 (percent)
u32 scale Y = 100
u32 tint = 0xffffffff (RGBA, white = untinted)
u32 X ← top-left position
u32 Y ←
u32 time (keyframe records only)
...
"opt " u32 len char[len] link to another record, e.g. "pgpbtn00f.rat"
```
- **X/Y is the sprite's top-left**, not its centre: compositing at these coordinates
reproduces the screenshot, which drawing centred on them would not.
- **The pivot at 0x50/0x54 is half the texture size** — 4 of the 5 plain sprites match
exactly (`pgpbtn00` 86×42 → 43,21; `pgpbtn05` 221×42 → 110,21; `pgptitle` 202×73 →
101,36; `pgpbtn04` 172×43 → 86,22). It is a rotation/scale centre, not a draw offset.
- **Animated elements are a keyframe list.** `pgptitle.rat` (752 B) is the same placement
block repeated with a varying trailing `time` field — the PAUSE title's fly-in.
- **`opt `** carries a length-prefixed record name. On `pgpbtn00.rat` it points at
`pgpbtn00f.rat`, i.e. *normal state → focused state*. Focused records place their sprite
42 px left and 8 px up of the base, because the focused art includes the selection ring
that hangs off the left edge; their pivot is a constant (21,25) rather than half-size.
- `<screen>loop1.rat` is **not** a screen composition — it is a looping sprite animation:
a 3-name table (`pgpeff34/35/36.t32`) plus ~30 keyframes all at one position.
- The small (380 B) top-level entries are **`PRMD` primitives**, not sprites: a colour and
four explicit corner coordinates `(0,0) (1280,0) (0,720) (1280,720)` — the full-screen
quad that dims the scene behind the pause menu — terminated by `end `.
### The records are language-independent
`pgpbtn00.rat` is **byte-identical** in the English and Japanese bundles. The layout is
authored once and only the `.t32` sprites are swapped, which has two consequences:
- The baked pivot belongs to *whichever build the record was authored from*, not to the
sprite actually shipped beside it. That is why `pgpbtn01`'s pivot (113 → a 226 px wide
texture) matches neither the English sprite (207) nor the Japanese one (148).
- The split is visible inside a single bundle: in the **English** tutorial build, every
`.t32` declaration carries the correct English pivot (7/7), while the `.rat` declarations
carry Japanese-derived ones (`btn10` → 43,21 = 86/2, the *Japanese* sprite). So the
`.t32` table is regenerated per language and the `.rat` layer is inherited from the
Japanese master.
- **Do not infer anything about a language from a texture size** — see the traps below.
## Evidence
Positions were read out of the records and checked against a screenshot of the running
game, twice, in that order — the records were never fitted to the picture.
1. **Differential.** Across `pgpbtn00/01/04/05.rat`, exactly one field varies and it steps
`268 → 338 → 408 → 478` — a constant 70 px pitch — while the field before it is 226 in
all four. A vertical menu: constant X, evenly spaced Y.
2. **Absolute placement — the decisive test.** The *tutorial* build's records give
546/288, 546/358, 546/428 and 540/119. Compositing its sprites at exactly those numbers,
with no offset and no fitting, reproduces the screenshot (image above).
3. **Pivot.** 4 of 5 plain sprites carry exactly half their texture's dimensions at
0x50/0x54 (above).
> A caution on step 2, because the first pass here got it subtly wrong: the screenshot is
> of the **tutorial** pause menu, so only the `pgp_ttrl_*` records can be checked against
> it. The in-mission records (X = 226) also map onto the same screenshot under a single
> constant offset — but that only works because both builds share the 70 px pitch, and it
> proves nothing. The in-mission coordinates remain **unverified**: confirming them needs a
> screenshot of a pause during an actual mission.
## It generalizes — the title screen
The same method run against `GP_TITLE.pak` reproduces the **main menu**, which is a
different screen with a different item count and a different pitch:
![main menu real vs rebuilt](captures/ui-layout/title-mainmenu-real-vs-rebuilt.png)
`ptbtn01..05.rat` give X = 542 for all five and Y = 162 / 242 / 322 / 402 / 482 — an
**80 px** pitch, where the pause menu used 70. Measured against the screenshot, the sprite
tops land at a constant **+46 px** for all five (one reads 45, a 1-px edge-detection
wobble), and 46 is exactly the 45 px of Xenia window chrome plus one. So the record's Y is
the sprite's top edge in the guest framebuffer, to the pixel, on a second screen.
`GP_TITLE.pak` also splits by sub-screen the way the pause pak splits by context:
`ptbtn00` alone (the `PRESS Ⓐ BUTTON` prompt), `ptbtn01..05` (main menu), `ptbtn11..13`
(the EXTRAS submenu), plus `pgloading_*` for the loading screen.
## Two traps this caught
Both were mistakes made during this analysis, caught by comparing against the real game —
recording them because a static-only reading would have shipped them:
- **Texture width does not identify a language.** English `RESUME` (166 px) and Japanese
`再開` (86 px) differ hugely, but Japanese `通信ログ` (148 px) is within a few px of an
English label. The first language assignment made here was wrong; rendering the sprites
is the only reliable check. (The records being language-independent makes this worse:
a record's baked pivot implies a texture width that matches *no* shipped sprite.)
- **The in-mission and tutorial pause menus are different sprite sets, not one set
re-packed.** In-mission is `RESUME / RADIO LOG / OPTIONS / BACK TO TITLE` (4 items,
`pgpbtnNN`); the tutorial is `RESUME / OPTIONS / BACK TO MENU` (3 items,
`pgp_ttrl_btn1N`). Matching the 3-item screenshot against the 4-item set suggests a
runtime slot-packing rule that does not exist.
## Next
- **Half of this gap is now closed.** The `eff*` / `deli*` / `msg` sprites have no
`.rat` of their own, and `loop1.rat` is an animation, so the question was where the
screen's draw list lives. **It is the bundle's own declaration table** (above): that
table is not the child listing — the children are grouped by type (every `.t32`, then
every `.rat`), while the declaration table names *elements*, in a plausible back-to-front
order, and it is exactly the missing set that appears there. For the in-mission pause
menu it lists 23: `eff11/12/10`, `eff02(+a)`, `eff03(+a)`, `eff01`, `title.rat`,
`btn00/01/04/05.rat`, `msg`, `deli1…4`, `eff30…33`, `loop1.rat`. Note what it does
**not** list: the focused button variants, which are reached through each base record's
`opt ` link — so the table is the screen's element set, not a resource inventory.
- **And the position is there too — the gap is closed.** Immediately after the
declaration table the bundle carries a **placement region, one group per element**:
```
group header: u32 element index (0,1,2… — the correspondence is stated, not inferred)
u32 keyframe count
then `count` keyframes, 40 bytes apart, each holding the familiar block:
u32 scale X = 100 u32 scale Y = 100
u32 tint = 0xffffffff
u32 X u32 Y (+ a trailing time field)
```
For the tutorial pause bundle this yields 11 groups for 11 elements, and every
group's header index and count match the blocks actually present. The values are
self-evidently right: the three menu buttons sit at X=546, **70 px apart**
(288 / 358 / 428), the title at (540,119), the message at (451,545), and the
`eff*` sprites carry multi-position fly-ins.
**Cross-checked against the records themselves:** `pgp_ttrl_btn10.rat` places its
sprite at **(546,288)** — identical to its inline group. So the inline region is
the same placement data, and it covers the `eff*` / `deli*` / `msg` elements that
have no record of their own.
A screen is therefore fully reconstructible from its bundle alone: **element list
and order** (declaration table) + **placement and animation** (this region) +
sprites, with `opt ` supplying focused states.
- The same method should now unroll the other screens directly; `GP_HANGAR_ARSENAL.pak`
(789 T8aD + 510 RATC) is the big one, and the ARSENAL `DATA SHEET` panel documented in
[weapon-datasheet-runtime.md](../weapon-datasheet-runtime.md) is a ready-made oracle for it.
- Tooling: `crates/sylpheed-formats/examples/ui_screen.rs` (inventory a screen pak, carve a
named RATC child), `sylpheed-cli pak textures` (decode every sprite).