Hoshe's blocking find: district_pos_at divided the latitude axis by
tex_h where the server forward map uses ta.h.saturating_sub(1)
(district_profile.rs:1436; ground-truth inverse aliveness_probe.rs:511)
— every off-equator click descended into the wrong district, up to
~20km drift, live-repro'd at 10.2km. Fixed to /(tex_h - 1.0) with the
reference implementation's degenerate-texture guard; verified against
the repro (row 50: old formula recovered 41, fixed recovers 50 exact).
Columns were already correct (longitude wraps — the asymmetry the
docstring documented but the code didn't implement).
Regression tests transcribe the server forward formula (source cited)
and round-trip three off-equator rows — one per hemisphere plus
near-pole — asserting EXACT recovery; a dedicated drift guard is
framed as Tyre's C2 (a client-side twin of a server mapping owns its
own round-trip proof). Root-caused the coverage hole: the old
equator test sampled tex_h*0.5 believing it was the equator pixel —
the true equator is (tex_h-1)*0.5, so the test never verified what it
claimed; corrected with the why documented.
Araminta's find: the descend reticle drew unconditionally on hover —
over a city the marker flared white (city-click signal) while the
reticle+extent label promised descent, though the click correctly
resolved to city data. Extracted _should_draw_descend_reticle() with
the missing _hovered_city.is_empty() clause; three state tests pin
shows-over-map / hides-over-city / hides-when-idle.
test_atlas_descend_entry 32/32; adjacent clusters no ripple; gdlint
clean (atlas_viewer.gd at exactly the 1000-line cap).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
jpmschweitzerandClaude Fable 5
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