Looked in four places. The bundle has no field: a primitive has no RATC child at
all and the declaration words are constant across every element of three measured
screens -- the two grounds ui-prm-primitives.md already used to refute a
bundle-side LAYER key, and they apply identically to blend.
The colour census: every full-screen *eff00* primitive on the disc carries pure
black at its various alphas, and the only non-black primitive anywhere is
pbafc.prm, RGB 00e8e0 cyan.
The occlusion constraint cannot reach that one. pbafc.prm looked alarming at a
declared 844x600 and alpha ff; it is a small moving glint. It strobes between
alpha 255 and 124 every 2 units, travels from x=178 to x=291, and is scaled
2%x3%, so it draws about 17x18 pixels. At that size it occludes essentially
nothing.
The oracle is unavailable: GP_READY_ROOM is a recorded no-go and gameplay needs
the A press that faults the guest in this container.
But the consequence closes even though the question does not. For a BLACK quad
-- which is every primitive forced_backdrop touches -- the hypotheses differ only
in whether it hides what is beneath. Drawn first it is correct under both; drawn
last it is correct only under additive. So the rule's verdict is robust to the
open question, and the port's original "layerless sorts last" was wrong under
alpha-over and merely pointless under additive. This is explicitly NOT evidence
for alpha-over.
The investigation also found forced_backdrop judging coverage from the pivot
alone, ignoring scale -- pbafc.prm is the disc's own proof that a nominally
844x600 element can draw at 2%. Checked before changing anything: all 80 forced
instances are at scale 100% on every opaque instant, so no verdict moved. The
guard now requires scale >= 100 at the instants it counts as opaque. Defensive,
not a fix. 4 + 13 disc tests green either side.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
65d309c553