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port: the 11.5 px was the fit's resolution -- and the lesson inverts

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The Decoder closed it by ADDING OBSERVABLES, not by tuning. The vertex buffer
carries positions and colours at the same instant, so all four quantities must
agree on one t: quad A x solves to 357.88 and quad B x to 357.58, both +/-0.12
units, against 355.75 +/-1.54 and 354.09 +/-1.89 from the alphas. Alpha moves
only 0.27-0.33 levels per unit, so one byte of quantisation is worth 1.5-1.9
units -- 6-8 px of sweep at 4 px/unit. That is the whole of the 11.5 px. At
t=357.7 the centres land within 0.70 px and both alphas inside one level.

THE LESSON IS THE EARLIER ONE INVERTED AND IT IS THE HALF WORTH KEEPING.
Checking a wrong rule against alpha made it look confirmed; here the same
insensitivity MANUFACTURED a residual that did not exist. An insensitive quantity
does not merely fail to falsify -- it invents error. Solve on the fastest-moving
field, check the slow one, never the reverse. I was already looking for a pivot
rule to explain 11.5 px when they wrote; there was nothing to find.

REFUTATION ATTEMPT, survived with a nuance: they state the leaf pivot is (200,90)
on a 399x180 sprite, "the pivot is the centre, so rotation displaces it by
nothing". Checked against my export -- pivot [200,90], sprite 399x180, true
centre 199.5,90. It survives, but the sprite is ODD-WIDTH so the pivot is the
centre to within half a pixel rather than exactly. No consequence against their
0.70 px agreement; worth stating because "displaces it by nothing" is the kind of
sentence that later gets leaned on for a sub-pixel claim.

verify-capture now poses the title at t=357.7 rather than 355: RMSE 21.07 ->
20.92, differing 1.82% -> 1.81%. Marginal, and it is the right pose for a stated
reason rather than a better number.

AND ptlogo_eff2 IS WITHHELD FOR A BETTER REASON THAN MINE. I had it on caution
about untested generalisation; the Decoder points out it is on title_jp and
MISSION section 7 scopes out "localisation beyond English", so it is not a
question this port has to answer and the parked Japanese capture does not need
reviving for it. authored/rendering.json now gives scope first and undecidability
second. Widening scope to close a residual would have been the wrong trade.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N7FiFFFwbvG2uxdcEh8HyF
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Sylpheed port agent
2026-08-29 18:25:04 +00:00
parent e5be03709a
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@@ -4257,3 +4257,56 @@ at alpha 160 and 80, each rotating 360° over 960 units — 16 s per revolution.
**If parent scale gates the leaf it is a 0.95 s flash; if the leaf runs free it
spins for 16 s.** Nothing on the disc chooses, `title_jp` has no oracle capture,
and the Japanese-locale capture MISSION has parked is what would settle it.
## The 11.5 px was the fit's resolution, and the lesson inverts
The Decoder closed it **by adding observables, not by tuning** — the vertex
buffer carries positions *and* colours at the same instant, so all four
quantities must agree on one `t`:
| observable | solved t | precision |
|---|---|---|
| quad A x | **357.88** | ±0.12 units |
| quad B x | **357.58** | ±0.12 units |
| quad A alpha | 355.75 | ±1.54 units |
| quad B alpha | 354.09 | ±1.89 units |
Alpha moves only 0.27–0.33 levels per keyframe unit, so **one byte of
quantisation is worth 1.5–1.9 units, which at 4 px/unit is 6–8 px of sweep**.
That is the whole of the 11.5 px. At t = 357.7 the centres land within 0.70 px
and both alphas inside one level.
⚠️ **The lesson is the earlier one inverted, and this is the half worth keeping.**
Checking a wrong rule against alpha made it *look confirmed*. Here the same
insensitivity **manufactured a residual that did not exist**. So an insensitive
quantity does not merely fail to falsify — **it invents error.** Solve on the
fastest-moving field; check the slow one; never the reverse.
I was already looking for a pivot rule to explain 11.5 px when they wrote. There
was nothing to find.
### Refutation attempt — the pivot claim, checked here and survived with a nuance
They state the leaf pivot is (200, 90) on a 399×180 sprite, *"the pivot is the
centre, so rotation displaces it by nothing."* Checked against my own export:
pivot **[200, 90]**, sprite **399×180**, true centre **199.5, 90**.
✅ Survives. ⚠️ With one correction of no consequence: the sprite is **odd-width**,
so the pivot is the centre to within **half a pixel**, not exactly. Against their
−0.70/−0.48 px agreement that changes nothing, and it is worth stating only
because "displaces it by nothing" is the kind of sentence that later gets leaned
on for a sub-pixel claim.
`verify-capture` now poses the title at **t=357.7** rather than 355: RMSE
21.07 → **20.92**, differing 1.82 % → **1.81 %**. Marginal, and it is the right
pose for a stated reason rather than a better number.
### `ptlogo_eff2` is withheld for a better reason than mine
I was withholding it out of caution about untested generalisation. The Decoder
points out something stronger: **it is on `title_jp`, and MISSION §7 scopes out
"localisation beyond English"** — so it is not a question the menu port has to
answer at all, and the parked Japanese-locale capture does not need reviving on
its account. `authored/rendering.json` now says that first and the undecidability
second. **Widening scope to close a residual would have been the wrong trade**,
and it is the human's call either way.