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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
This commit is contained in:
Sylpheed port agent
2026-08-29 18:25:04 +00:00
parent 42474642e0
commit 8994ca7c59
3 changed files with 89 additions and 15 deletions
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24
authored/rendering.json
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@@ -13,19 +13,29 @@
"one consistent time, then PREDICTED the quad centres to ~11 px. That covers",
"`ptloop01` and `ptloop02` and nothing else."
],
"draw_leaf_for": ["ptloop01", "ptloop02"],
"draw_leaf_for": [
"ptloop01",
"ptloop02"
],
"draw_leaf_why": [
"The two the decode covers. `docs/re/structures/ui-leaf-vs-parent-alpha.md`.",
"",
"NOT DRAWN, though the exporter flags them and ships their data:",
"",
" `title_jp/ptlogo_eff2` -- parent 125% at (412,96), leaf 100% at (402,66).",
" It is the same SHAPE as the ptloop case and it is the element DECISIONS has",
" recorded since P1 as the largest render disagreement in the export. The",
" Decoder said in as many words: 'I have not tested it.' Drawing it would be",
" extending a decode past the case it was fitted on, which is the failure",
" this port has made four times this session.",
" `title_jp/ptlogo_eff2` -- OUT OF SCOPE, which is a better reason than",
" the caution this entry first gave. MISSION section 7 scopes out",
" 'localisation beyond English', and this element exists only on the",
" Japanese title. So it is not a thing the menu port has to answer, and the",
" parked Japanese-locale capture does not need reviving on its account --",
" that is the human's call and not something either agent widens quietly.",
"",
" It is ALSO undecidable here even if it were in scope. Its 125% is a POP,",
" not a steady scale: scale-0 -> 125% -> scale-0 between t=50 and t=107,",
" about 0.95 s. The leaf draws at 100%, as two superimposed copies at alpha",
" 160 and 80, each rotating 360 degrees over 960 units -- 16 s a turn. 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 and title_jp has no oracle",
" capture.",
" `build_12,15/pgloading_loop5` -- leaf scale (0,0). A zero scale is one of",
" the three historical failures this corpus names, so it is exactly where a",
" guess is most expensive.",

53
docs/port/DECISIONS.md
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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.

27
tools/port/verify-capture
View File

@@ -52,18 +52,29 @@ CAPS=docs/re/captures/title-builds
MAP=(
"main_menu:$CAPS/live-main-menu.png:menu"
"extras:$CAPS/live-extras.png:menu"
# ⚠️ THE TITLE IS POSED AT t=355 UNITS, NOT AT ITS SETTLE, and the time is
# ⚠️ THE TITLE IS POSED AT t=357.7 UNITS, NOT AT ITS SETTLE, and the time is
# MEASURED rather than chosen. The two `ptloop` sweeps are a continuous
# animation whose leaf group ends at t=600 with the quads parked off-screen at
# x=1521, so posing at the settle compares a still frame against a capture
# taken mid-sweep and simply omits them. The Decoder fitted t=355 from the
# game's own composed alpha -- per-draw vertex colours 195 and 182 against the
# two leaf ramps -- and the same t then predicted the quad centres to ~11 px.
# taken mid-sweep and simply omits them.
#
# t=357.7 is the Decoder's REFINED fit, and the refinement is worth knowing.
# Its first value, 355, came from the two per-draw alpha bytes alone and left
# an 11.5 px residual that looked like a pivot problem. Solving the same
# instant on the vertex POSITIONS instead gives t=357.88 and 357.58 to
# +/-0.12 units, against +/-1.54 and +/-1.89 from the alphas -- alpha moves
# only 0.27-0.33 levels per unit, so one byte of quantisation is worth 6-8 px
# of sweep. At 357.7 the centres land within 0.70 px and both alphas inside one
# level. THE 11.5 px WAS THE FIT'S RESOLUTION, NOT GEOMETRY.
#
# ⚠️ And there is no pivot correction: the leaf pivot is (200, 90) on a 399x180
# sprite, so it is the centre to within half a pixel -- checked here against
# the export rather than taken.
#
# ⚠️ It is NOT the time that minimises the difference: t=390 measures 1.65 %
# against 1.82 % here. Picking that one would be fitting the pose to the
# score, which is the thing this harness exists not to do.
"title:$CAPS/live-title-build4-no-plate.png:t355"
"title:$CAPS/live-title-build4-no-plate.png:t357"
"publisher_logo:$CAPS/live-splash-publisher.png:screen"
"developer_logos:$CAPS/live-splash-developer.png:screen"
)
@@ -83,8 +94,8 @@ for row in "${MAP[@]}"; do
godot --path port --resolution 1280x720 -- "--menu=$name" --script=wait \
"--shots=$OUT/$name" >"$OUT/$name.log" 2>&1 || true
[ -f "$OUT/${name}_00_start.png" ] && cp "$OUT/${name}_00_start.png" "$OUT/$name.render.png"
elif [ "$pose" = t355 ]; then
godot --path port --resolution 1280x720 -- "--screen=$name" --time=5.9167 \
elif [ "$pose" = t357 ]; then
godot --path port --resolution 1280x720 -- "--screen=$name" --time=5.9617 \
"--capture=$OUT/$name.render.png" >"$OUT/$name.log" 2>&1 || true
else
godot --path port --resolution 1280x720 -- "--screen=$name" --time=99 \
@@ -98,7 +109,7 @@ for row in "${MAP[@]}"; do
note=""
case "$name" in
main_menu|extras) note="rendered with authored initial focus" ;;
title) note="posed at t=355, the Decoder's fitted sweep time" ;;
title) note="posed at t=357.7, the Decoder's refined sweep fit" ;;
esac
# Where the difference lives. This comes FIRST because it is what the gamma
# sweep has to be protected from.