Live verification (2026-04-23, Phase 3c launch): acdream picked
DayGroup[17] "Rainy" for PY106 day46 while retail at the same server
tick showed clear blue sky with white clouds (Sunny-ish). Root cause:
our port passed the RELATIVE year (106, i.e. years since tick-0) into
the LCG seed, while retail's TimeOfDay+0x64 is ABSOLUTE Year =
floor(...) + ZeroYear (baseYear=10 for Dereth GameTime). The offset
seeds the LCG with `seed = 106×7620+46` vs retail's `seed =
116×7620+46` — `10 × SecondsPerDay = 76200` apart, guaranteed to
land on a different DayGroup index.
Fix:
- DerethDateTime.ZeroYear constant (= 10) + AbsoluteYear(ticks) helper.
- GameWindow.RefreshSkyForCurrentDay feeds AbsoluteYear into the picker.
- LoadedSkyDesc.ActiveDayGroup(ticks) same.
- Calendar display and generic Year(ticks) stay relative; only the
LCG-seed path uses the offset. Matches retail FUN_005a7510:5300 which
explicitly adds baseYear to the relative year before stashing in
TimeOfDay+0x64.
Build + 717 tests green. Next visual check should show matching
weather with retail client side-by-side.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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