User-observed regression 2026-04-23: acdream spawned rain particles
when retail showed no rain at the same server tick. Root cause: my
Phase 3e shortcut mapped DayGroup.Name = "Rainy" → WeatherKind.Rain →
rain particle emitter. That's not what retail does.
Parallel decompile research confirms:
- Agent A (2026-04-23-physicsscript.md): PhysicsScript runtime lives
at FUN_0051bed0 → FUN_0051bfb0, runs per PhysicsObj; sky calls it
from NOWHERE.
- Agent B (2026-04-23-sky-pes-wiring.md): FUN_00508010 (sky render
loop) never reads SkyObject.DefaultPesObjectId — the field is dead
at render time. Rain/snow particles in retail come from a separate
camera-attached weather subsystem that has NOT yet been located.
So the correct behavior is: DayGroup name should only drive
fog/ambient tone (via keyframes, already in the Snapshot path),
never spawn particle emitters. Any retail-faithful particle rain
belongs to a future phase once we find the camera-attached weather
subsystem driver.
Change: MapDayGroupNameToKind now maps all weathery substrings
(storm/snow/rain/cloud/overcast/dark/fog) → Overcast — fog-only
visuals, no particle spawn. Clear names stay Clear. The Rain, Snow,
Storm enum values remain and are still accessible via ForceWeather()
for debug overrides.
Tests updated (WeatherSystemTests): the name→kind theory now expects
Overcast for Rainy/Snowy/Stormy variants.
Also commits the four research docs from this session's parallel
hunt: PhysicsScript dat+runtime, sky↔PES wiring (negative finding),
lightning timer (negative finding — agent #3), fog on sky
(positive: retail applies fog to sky geometry).
NOTE on lightning: agent #3's research only ruled out the CLIENT-SIDE
RANDOM TIMER hypothesis for lightning. User confirms retail does have
visible lightning + thunder. A follow-up agent (#5, in flight as of
this commit) is hunting the real mechanism — PlayScript opcode,
SetLight PhysicsScript hooks, AdminEnvirons side effects, or the
weather-volume draw. This commit does NOT attempt to port lightning.
Build + 733 tests green.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
User reported rain in acdream while retail showed a clear sunny sky
after Phase 3d landed. Root cause: two independent weather systems
running in parallel.
1. Retail DayGroup picker (FUN_00501990 port, Phase 3c/3c.1) —
selected DayGroup[6] "Sunny" correctly.
2. WeatherSystem.Tick (legacy stub from pre-decompile era) —
kept rolling its own hardcoded PDF every day (60% Clear, 20%
Overcast, 12% Rain, 5% Snow, 3% Storm), independent of the
DayGroup picker. Its output drove the rain/snow particle
emitters via UpdateWeatherParticles. If its hash happened to
land on Rain for today's dayIndex, rain rendered even on a
Sunny DayGroup day.
Retail has ONE source of truth for weather: the DayGroup roll. There
is no separate weather state machine — rain/snow/storm are implied by
the DayGroup name and its per-keyframe SkyObjectReplace settings.
Fix (Phase 3e):
- WeatherSystem.SetKindFromDayGroupName(string?) — loose substring
match on the retail DayGroup name: "storm" → Storm, "snow" → Snow,
"rain" → Rain, "cloud"/"overcast"/"dark"/"fog" → Overcast, else
Clear. Case-insensitive. Covers the names observed in the live
Dereth dat dump (Sunny, Clear, Cloudy, Rainy + inferred variants).
- WeatherSystem._externallyDriven flag disables the internal
RollKind auto-roll once SetKindFromDayGroupName has been called at
least once. Tests that drive Tick() directly keep the legacy
hash-roll behavior (offline fallback). ForceWeather still works
for debug overrides.
- GameWindow.RefreshSkyForCurrentDay calls
Weather.SetKindFromDayGroupName(grp.Name) right after it installs
the new SkyStateProvider. Logs the resulting WeatherKind on the
same line as the DayGroup pick for correlation.
- New WeatherSystemTests.SetKindFromDayGroupName_MapsRetailNames
(theory, 14 cases) + SetKindFromDayGroupName_DisablesInternalRoll.
Expected effect: Sunny/Clear DayGroups → no rain emitter. Rainy/Stormy
DayGroups → rain emitter active. The user's specific scenario
(DayGroup[6] "Sunny") now correctly maps to WeatherKind.Clear and no
particles spawn.
Build + 733 tests green (+16 new).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
User observed: 'time is flipped — supposed to be day/evening, but shows
night/morning.' That's a ~half-day offset.
Root cause in ACE DerethDateTime.cs line 23:
private const double dayZeroTicks = 0; // Morningthaw 1, 10 P.Y. - Morntide-and-Half
ACE anchors tick 0 to Morntide-and-Half (slot 7 on the 0-indexed 16-slot
scale) — NOT Darktide (slot 0 = midnight) as our DayFraction function
assumed. Confirmed by DerethDateTime.cs:145:
private int hour = (int)Hours.Morntide_and_Half;
Fix: shift DayFraction by +7/16 * DayTicks (3333.75) so tick 0 maps to
its real calendar slot. Exposed as DayFractionOriginOffsetTicks constant
for documentation + downstream referencing.
Effect on sun: previously, server tick ~0 (just-booted ACE) produced
dayFraction 0 → midnight sky → night colors at noon real-time.
Now dayFraction 7/16 = 0.4375 → late morning sky → noon-ish colors
within 1/16 of a day, which matches what a user actually sees when
launching during daytime.
Tests updated for the corrected convention:
- DerethDateTime.DayFraction(0) = 7/16 (not 0).
- CurrentHour(0) = MorntideAndHalf (not Darktide).
- IsDaytime(0) = true.
- Midnight (Darktide, slot 0) is 9/16 of a day past tick 0.
- SkyState + WorldTimeDebug tests retargeted to the new frame.
Build green, 711 tests pass.
Ref: references/ACE/Source/ACE.Common/DerethDateTime.cs:23-25 + :145.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Small polish commit:
- Clamp ClearColor inputs to [0, 1] because retail keyframes store
sun/fog colors pre-multiplied by their brightness scalars, which can
exceed 1.0; some drivers treat ClearColor > 1 as a saturate-bright
hint and produce visible color shifts at the edges.
- 4 new tests cover WorldTimeService.SetDebugTime / ClearDebugTime /
SyncFromServer-clears-override / SetProvider hot-swap.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Expand the SkyKeyframe record with retail-exact fog fields (FogStart,
FogEnd, FogMode) per r12 §5. The existing FogDensity field is retained
for backwards compat with tests that pin it; new shipping code reads
FogStart / FogEnd / FogMode directly.
Add WeatherSystem (WeatherKind + EnvironOverride enum + 10s transition
ease + deterministic per-day-index roll) matching r12 §6.1. Roll weights
are ~60% Clear / 20% Overcast / 12% Rain / 5% Snow / 3% Storm — tuned
against retail observations. Storm mode triggers lightning flashes
every 8–30 s via an exponential-decay (200ms τ) flash level that the
shader consumes as an additive scene bump.
Add SkyDescLoader that parses the Region dat (0x13000000) into
LoadedSkyDesc — DayGroupData with SkyObjectData (visibility window +
arc sweep), per-keyframe SkyObjectReplaceData, and a shader-ready
SkyStateProvider builder. Sun/ambient colors are pre-multiplied by
DirBright/AmbBright so the shader never needs to know about retail's
scalar brightness field.
19 new tests (weather determinism, transition ease, environ override
tint, flash decay, dat-load conversion with fog + pre-mult colors).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Client-side deterministic sky + weather + day/night system per R12.
Retail's model is 95% client-side: the server just delivers its
current PortalYearTicks (double, seconds since boot-seed) at login and
in TimeSync packets; the client computes everything else locally from
the constants in r12 §1.2 + ACE DerethDateTime.cs.
Core layer (AcDream.Core/World):
- DerethDateTime: retail-exact calendar (16 hours/day, 30 days/month,
12 months/year, 7620 ticks/day, 2,743,200 ticks/year). HourName enum
covers all 16 named half-hour slots (Darktide → GloamingAndHalf);
MonthName covers the 12 Derethian months (Snowreap → Frostfell).
DayFraction, CurrentHour, IsDaytime, ToCalendar.
- SkyKeyframe + SkyStateProvider: 4-keyframe default day/dawn/noon/dusk
with linear color + angular-wrap heading interpolation + slerp-like
shortest-arc lerp so heading wraps 350° → 10° don't tween backwards
through 180°. Default keyframe colors tuned to retail screenshots
(sunrise warm, noon white, sunset red, midnight deep blue).
- WorldTimeService: owns the live clock. SyncFromServer(ticks) sets
baseline; NowTicks advances by real-time elapsed. Exposes DayFraction,
CurrentSky, CurrentSunDirection, IsDaytime for the render thread.
This is the foundation Phase G.2 (dynamic lighting) consumes: lighting
uniforms are fed from CurrentSky's SunColor / AmbientColor / sun
direction, varying smoothly across the day.
Tests (16 new):
- DerethDateTime: midnight, half-day, wrap, Dawnsong, Midsong,
day/night flag at dawn vs Darktide-Half, year rollover, month
advance.
- SkyState: 4-default keyframes, noon-exact matches frame data,
midpoint lerps between neighbours, wrap across midnight doesn't
produce NaN, sun direction returns unit vector, WorldTimeService
sync + DayFraction at noon.
Build green, 587 tests pass (up from 570).
Ref: r12 §1 (Portal Year math), §2 (sky objects), §4 (color lerp).
Ref: ACE DerethDateTime.cs + NetworkSession TimeSync handler.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
StepUpHeight: when Tab enters player mode, read Setup.StepUpHeight from the
player entity's dat and apply it to the controller (fallback 2f for non-Setup
entities or when the dat value is zero). Previously hardcoded to 5.0 which
made step-up too permissive.
Road exclusion: SceneryGenerator now skips terrain vertices where bits 0-1 of
the raw terrain word are non-zero. These bits encode the road type (GetRoad()
in ACViewer's Landblock.cs). Trees, rocks and bushes will no longer be placed
on road surfaces.
Added SceneryGenerator.IsRoadVertex(ushort) public helper + 9 unit tests
(theory + fact) verifying the road-bit convention matches TerrainInfo.Road.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
