The port pre-registered a test and ran it: against live-splash-publisher.png
a cropped render scores RMSE 558.1 (0.85%) and a scaled one 10118.8
(15.4%). Cropping is 18x better.
Confirmed here independently, from a different observable: the committed
captures are 1279x675, 1280x690 and 1252x754. VARYING heights. A fixed
presenter resample produces one size; crops of differently-sized windows
produce exactly that spread. And ui-render-tone-curve.md had already
recorded every capture aligning at dy=0 dx=0 with correlation 0.9466, which
a 0.9375 vertical scale cannot produce -- the evidence was in the corpus
before I wrote the claim.
So the captures are crops of a 1:1 surface, and every RMSE, glyph count and
surface mean against them is pixels to pixels with no filter to caveat. The
blanket "everything measured off a PNG carries the resample" is withdrawn.
Not refuted: the cvar reading. Canary does letterbox by default. What is
refuted is my inference that the corpus's capture path went through it.
Whether the presenter is bypassed, the window is 1:1, or the tool crops
before saving is open and unestablished.
The error is the one this session keeps paying for: I read a configuration
and inferred a consequence FOR THE DATA without testing it against the
data. The test costs one render and one RMSE and I had every capture needed
to run it.
Also downgrades my refutation of the corpus's oracle principle from
"survives with a qualifier" to "survives, and my qualifier was wrong",
kept rather than deleted because the failure is the instructive part.
Section 1 (gamma: VdGetCurrentDisplayGamma is kStub, the splash shader has
no pow/ramp/lookup) and the two-path distinction stand unchanged.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jc4pciRArGHfxGGhEbwp5t
Answers question 3 of the 2026-09-02 play-test, from Canary's own source.
Gamma: Canary applies NONE. VdGetCurrentDisplayGamma is declared kStub and
only reports kernel_display_gamma_type (default 2, TV/BT.709) to the guest
so D3D can build a ramp. And the guest does not apply one either, for the
splash: its dumped pixel shader is four ALU ops -- tfetch2D, three muls, a
max -- with no pow, no ramp, no lookup.
Geometry: yes, the presenter resamples. present_letterbox defaults true and
present_safe_area_x/y default to 100, so the guest's 1280x720 is scaled to
fit the window and letterboxed with nothing cropped. That accounts for a
number the corpus has carried without explaining: captures measure the game
surface at 1279x675, and a single-pixel oracle placed at 1280x720
coordinates read the copyright line instead.
The structural consequence is the useful part. There are two measurement
paths and only one has Canary in it:
pixels guest draw -> EDRAM -> resolve -> front buffer ->
presenter (scale + letterbox) -> X11 -> screenshot -> PNG
=> carries a resample
vertex stream guest CPU writes a vertex buffer -> the draw logger reads
guest memory directly
=> carries nothing
The per-frame alpha series is the second path, which is why it can be
stated as the game's values rather than as pixels we measured. Everything
measured off a PNG carries the resample: every RMSE against a capture,
every glyph count, every surface mean.
Refutation attempt on this corpus's own founding principle, "the oracle is
the real game running in Canary, captured": it SURVIVES but needs a
qualifier it has never carried. A PNG capture is the oracle plus a
resample. Harmless for ordering, counts, durations and change; a filter in
the path for anything pixel-exact. The vertex stream is the stronger oracle
and should be preferred where the question can be asked of it.
Not measured: the resample's actual filter. I read the cvars saying scaling
happens, not the kernel doing it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jc4pciRArGHfxGGhEbwp5t
