QA played the southerly at 65 km/h under a noon-blue sky with razor midday
shadows. The arithmetic said why: sky, sun and hemi all multiplied the weather
by the author's palette (darkness 0.5 on the southerly), so the dial could
zero the weather's say — 0.69 storminess became a 0.35 nudge. The grade floors
it (storminess x lerp(0.5, 1, darkness)): a full gale now goes at least half
way to slate on any palette while the wild night keeps its authored black.
Plus the two things nothing keyed at all: the sun disc lerps toward slate and
sun.shadow.radius lerps 1->7 on storminess (PCFSoft, so it is real blur).
Deterministic — pure in t, same curve the rain uses, exposed as sky.stormGrade
above the render gate for headless reads. dispose() hands back intensity,
colour and radius exactly.
Verified by eye in dev_skyfx: southerly t=55, 18.5 m/s reads slate weather.
Selftest 337/0/0 (+1 test). Mutation-checked: the old formula and a dropped
radius line both go red.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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