# A textured element carries no blend/alpha mode — ❔ undecodable, with reach

> ✅ **SUPERSEDED IN ITS CONCLUSION, 2026-08-31 — the route this page named as
> "the one left" was taken, and it answered.** The frames are drawn **ADDITIVE**
> (`RB_BLENDCONTROL0 = 0x01010101`, src `ONE` / dst `ONE`), measured off the GPU
> per draw on two screens:
> [`ui-blend-mode-measured.md`](ui-blend-mode-measured.md).
>
> What survives here is the **negative and its reach**, and it is still the
> reason the answer had to come from the running game: no field of the
> declaration entry, no word or bit of the `T8aD` header, and no field of the
> keyframe record separates the four too-dark frames from the elements rendered
> accurately beside them. The disc-side reach was also **widened** after this
> page was written — four elements over two screens, and a per-bit sweep — in
> [`data/frame-blend-field-hunt.txt`](../data/frame-blend-field-hunt.txt).
>
> ⚠️ **And the sentence this page ends the port's question with — *"any blend you
> choose is authored and must carry that label"* — is now WRONG as guidance.** It
> was true of the disc; it is not true of the game. Additive is transcribed, not
> authored. It was delivered to the port in that form and has been corrected
> there too.


**Answers `sylpheed-port`'s ask**: what blend/alpha mode do `ptframe1` and
`ptframe2` use on the main menu? They measure those two elements as the only ones
whose residual is **higher on flat pixels than on edges** (25.41/16.54 against
19.85/9.82), signed one direction, `ptframe1` rendering at 88.4 against the
capture's 129.1 with 0.1 % of pixels render-brighter — a body-intensity difference,
not a geometric one.

## The answer: it is not on the disc, and the port is authoring

⚠️ Prior work covers **`.prm` primitives**
([`ui-prm-blend-mode.md`](ui-prm-blend-mode.md), ❔ undecodable with reach) and a
**refuted** `T8aD +0x04` bit. Neither covers a `.t32` element, which is what was
asked. This does.

### Reach 1 — the declaration entry (60 bytes, all 15 words read)

| words | what they are |
|---|---|
| `+0x00`–`+0x0B` | the **name** string (`ptfr`, `ame1`, `.t32`) |
| `+0x0C`–`+0x1F` | **constant 0** across every element on the screen |
| `+0x20`, `+0x24` | constant `FFFFFFFF` |
| `+0x28` | **kind** — 0 plain, `0x10` primitive, `0x3002` button |
| `+0x2C` | **focus/nav index** — `−1` for non-buttons, 1…5 for the five buttons |
| `+0x30`, `+0x34` | position / pivot |
| `+0x38` | constant 0 |

🔴 **The two frames are `kind 0` — identical to `ptbase`, `pteff05`, `pteff10`,
`pteff12` and `ptmsg`.** Nothing in the declaration distinguishes them.

⚠️ A first pass reported `+0x00` and `+0x08` as "separating the frames". **False
positive of my own test**: those words are the name, and the frames share a prefix
and a suffix no other element has.

### Reach 2 — the sprite's own `T8aD` header, and a candidate I refuted

`+0x08` is the one word where both frames agree on a value no other menu sprite
has: **`0x8050`**. Tested disc-wide before offering it:

* **38 sprites carry `0x8050`, only 8 named `*frame*`** — not frame-specific;
* the **high byte tracks the archive** — `0x80xx` in `GP_TITLE`, `0xb1xx` in
  `GP_OPTIONS`, `0xd8xx` in `GP_GAMEOVER`, `0xf0xx` in `GP_DIALOG`.

❌ So `+0x08` is an atlas/format word, **not a mode**. The candidate is dead.

## What this means for the port

**Any blend the port picks for these elements is authored, not transcribed**, and
must be labelled that way. ✅ Their refusal to brighten the frames until they match
is the right call for the reason they gave: a blend invented on their side is
indistinguishable from a decoded one in a month — and this page is the evidence
that there is nothing to decode it *from*.

⚠️ **Reach of the negative**: one screen's declaration table read exhaustively, the
`T8aD` header's low words compared across every sprite on that screen and one
candidate word censused disc-wide. **Not looked at**: the executable's draw path,
which is where a mode selected in *code* rather than *data* would live. That is a
route, and it is the one left.