port: the loading screens are no longer black -- it was the paint order

verify-screen's header has said since P1 that build_12/build_15 render pure black
in both renderers, with an open question whether that was the port's bug or the
decoders' reading of rest. Measured today: max 214.5 on both sides, mean 1.949
port against 1.918 reference. Not blank, and they agree.

It was the paint order. My own earlier measurement had already answered it and I
had not connected them: removing the forced-backdrop pass makes the first element
pgloading_loop5 and the black screen returns. pgloading_eff00 carries layer: null,
layer_source: none -- the only elements in the export with neither a read nor an
implied key -- so its position rests entirely on the occlusion constraint.

The guard stays, with the stale paragraph kept as history. It was right when
written, and a guard that stops firing is the kind that rots out of a tool.

Refutation attempt on the Decoder's census scope: my six transient
ptlogo_back2eff* on title are also GP_TITLE, so if they were fallback fires their
count of four would be wrong. Their claim survives -- all six reach rest by the
plateau path, alpha 255->255 with identical pos and scale, so the fallback never
runs. The two censuses differ in scope, not in fact.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N7FiFFFwbvG2uxdcEh8HyF

docs/port/DECISIONS.md

@@ -9,7 +9,7 @@ dies, which is what this file is for.
 
 <!-- INDEX: generated by tools/port/index-decisions -- do not hand-edit -->
 
-151 sections. Search this before re-deriving anything.
+152 sections. Search this before re-deriving anything.
 
 * [P0 — the exporter, 2026-08-28](#p0--the-exporter-2026-08-28)
 * [P1 — Godot draws the screen, 2026-08-28](#p1--godot-draws-the-screen-2026-08-28)
@@ -162,6 +162,7 @@ dies, which is what this file is for.
 * [🔴 CORRECTION: the port did not move away from the game — I scored the wrong frame](#correction-the-port-did-not-move-away-from-the-game--i-scored-the-wrong-frame)
 * [The `rest()` flash defect reaches four screens I ship — and the port already survives it](#the-rest-flash-defect-reaches-four-screens-i-ship--and-the-port-already-survives-it)
 * [Correction: those two are the *sound* path, which makes the rule stronger](#correction-those-two-are-the-sound-path-which-makes-the-rule-stronger)
+* [The two loading screens are no longer black, and it was the paint order](#the-two-loading-screens-are-no-longer-black-and-it-was-the-paint-order)
 
 <!-- /INDEX -->
 ## P0 — the exporter, 2026-08-28
@@ -8804,3 +8805,51 @@ eight — both titles, both splashes and their region twins, and both loading
 screens. ✅ None of it reaches shipped output: the port poses `pose_at(hold)` and
 agrees with every capture it has. The number bounds what would break the day
 anything scored a `rest` frame against an oracle.
+
+## The two loading screens are no longer black, and it was the paint order
+
+`verify-screen`'s header has carried, since P1, that `build_12` and `build_15`
+*"render as pure black in BOTH renderers, mean 0 and max 0"*, with an open
+question: *"whether that is the port's bug or the decoders' reading of `rest`"*.
+
+✅ **Both halves are now settled, and the answer is neither.** Measured today:
+
+| | max | mean |
+|---|---|---|
+| port | 214.5 | 1.949 |
+| reference | 214.5 | 1.918 |
+
+Not blank, on either side, and the two agree — the rows read `OK` on a real
+comparison rather than on nothing-against-nothing.
+
+🔴 **It was the paint order, not `rest`.** My own earlier measurement had already
+answered it and I had not connected the two: removing the forced-backdrop pass
+makes these screens' first element `pgloading_loop5`, *"and the black screen
+returns"*. `pgloading_eff00` is the full-frame opaque untextured quad, and it
+carries `layer: null`, `layer_source: none` — the only elements in the export with
+neither a read nor an implied key. Its position rests entirely on the occlusion
+constraint. The rule that fixed it is the one the Decoder supplied and I
+implemented this session.
+
+⚠️ **The guard stays and the stale paragraph stays with it**, marked as history.
+It was correct when written — two of sixteen rows were reporting this script's
+strongest verdict for comparing nothing against nothing — and a guard that stops
+firing is exactly the kind that rots out of a tool. A reader who hits a blank pair
+tomorrow needs the reasoning, not just the verdict.
+
+### Refutation attempt: does the Decoder's census miss my title screens?
+
+Their `GP_TITLE` census is *"5 fires, 4 visible, all four on the splash screens"*.
+My own census found six transient `ptlogo_back2eff*` elements on `title` and seven
+on `title_jp` — also `GP_TITLE` builds. If those were fallback fires, their count
+of four would be wrong.
+
+✅ **Their claim survives.** All six reach `rest` by the **plateau** path — alpha
+255→255 with identical `pos` *and* `scale` across the pair — so `rest_plateau()`
+handles them and the dwell fallback never runs. They are not fires.
+
+📌 Which is their own point back at them, now with my screens as evidence: my
+census counts a **superset spanning both paths**, and the difference between the
+two numbers is not disagreement but scope. A plateau that happens to sit on a
+transient's peak is invisible to a fallback census and still produces a rest frame
+the game never shows.

tools/port/verify-screen

@@ -202,6 +202,20 @@ print(json.load(open("export/"+f))["source"]["build"])' "$name")
   # is the port's bug or the decoders' reading of `rest` is open; what is not
   # open is that a blank pair may not be scored.
   #
+  # ✅ RESOLVED 2026-08-30, AND THE PARAGRAPH ABOVE IS NOW HISTORY. It was the
+  # PAINT ORDER, not `rest`. `pgloading_eff00` carries `layer: null`,
+  # `layer_source: none` -- the only elements in the export with neither a read
+  # nor an implied key -- so without the forced-backdrop pass the first element
+  # becomes `pgloading_loop5` and the opaque quad paints over everything. With
+  # the pass, both screens render at max 214.5 in BOTH renderers (mean 1.949
+  # port, 1.918 reference) and the rows read `OK` on a real comparison.
+  #
+  # ⚠️ The guard STAYS. It is not firing today, which is exactly when a guard
+  # quietly rots -- and it was right when it was written: two of sixteen rows
+  # were comparing nothing against nothing and reporting this script's
+  # strongest verdict. Leaving the reasoning above intact is deliberate; a
+  # reader who hits a blank pair tomorrow needs it.
+  #
   # So blankness is checked FIRST and reported as its own verdict. It is not a
   # failure -- the port may legitimately have nothing to draw -- but it is not a
   # pass either, and `status` is left alone so an unrelated screen's DIFFERS is