`tools/port/verify-screen` line 20 has said "use `tools/verify-capture` for the
correctness question" since P1, and there was no such file. The port has had a
harness comparing itself to sylpheed-cli -- two renderers sharing its assumptions
-- and none comparing it to the game, while its own docs said otherwise. That gap
is what ORACLE-CAPTURES.md warns about: this corpus has been bitten three times
by two renderers agreeing, and every one was obvious against a capture.
Five screens against framebuffer captures of the real game:
main_menu RMSE 14.79 0.25% differing focus state may differ
extras RMSE 15.29 0.46% focus state may differ
title RMSE 21.07 1.82% ptloop sweeps never stop
publisher_logo RMSE 10.77 1.00%
developer_logos RMSE 9.37 0.39%
NO SCREEN SHOWS A LARGE CONNECTED BLOB -- the shape a missing element makes, and
the shape all three historical failures made.
And 74.1% of main_menu's differing pixels fall inside the ORACLE'S OWN focus
signature (live-main-menu vs live-main-menu-options-focused, the same screen with
a different button lit). So the bulk of that disagreement is a state mismatch,
not a defect.
REFUTATION ATTEMPT, on ui-render-tone-curve.md's `capture = 255*(render/255)^g`.
It survives where it was measured and not past it. Binning every structurally
matched pixel by render level gives the relationship directly, and the implied
exponent is NOT constant: 1.26 at render 16, 1.10 at 32, crossing 1.0 near 44,
down to 0.69 at 96. Above ~44 the capture is BRIGHTER than the render, which one
exponent cannot express -- and that is exactly why my whole-frame fits kept
returning 1.00, the two halves cancelling. The page's own stated reach ("nothing
constrains midtones or highlights") was not a hedge, it was the finding. Its 1.49
for this screen measures 1.18-1.26 in my darks; recorded as a disagreement rather
than resolved, since they fit selected flat patches and I binned everything.
Two earlier versions of this tool reported a best-fit gamma and were wrong both
times -- once fitting across a 74% structural mismatch, once extrapolating past
the measurement's stated reach. The fix was not a better fit but a different
instrument: it prints the curve, which somebody can argue with.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N7FiFFFwbvG2uxdcEh8HyF
ca23a5479a