fix(lighting): A7 Fix D round 2 — outdoor objects get NO torches (retail useSunlight gate) (#140)

The Holtburg meeting-hall facade washed out warm/bright vs retail. The round-1
checkpoint blamed torch REACH (acdream Falloff 6×1.3=7.8m vs a supposed retail
Falloff 4). That theory is WRONG, and this commit fixes the real cause.

Empirical (HoltburgTorchFalloffProbeTests, headless dat dump via the production
LightInfoLoader): the orange entrance torch (setup 0x020005D8) is raw dat
Falloff 6 and acdream reads it FAITHFULLY — there is no Falloff-4 torch anywhere
in Holtburg. Both clients read the same dat float, so reach was never inflated.

Decomp (read verbatim + corroborated by an independent adversarial workflow):
retail's per-object torch binder minimize_object_lighting (0x0054d480) is gated
in RenderDeviceD3D::DrawMeshInternal (0x0059f398) by `if (Render::useSunlight == 0)`.
The outdoor landscape stage runs useSunlightSet(1) (PView::DrawCells 0x005a485a,
before LScape::draw), so the building EXTERIOR shell — drawn via
DrawBlock→DrawSortCell→DrawBuilding→CPhysicsPart::Draw→DrawMeshInternal — is lit
by SUN + ambient ONLY; torches are SKIPPED. The static bake
(SetStaticLightingVertexColors 0x0059cfe0) is EnvCell-only. So retail NEVER
torch-lights outdoor objects. This exactly explains the isolation test (object
point lights OFF → building matches retail).

Fix: WbDrawDispatcher.ComputeEntityLightSet gates per-object torch selection on
the object being INDOOR (ParentCellId is an EnvCell, (id&0xFFFF)>=0x0100) via the
pure predicate IndoorObjectReceivesTorches. Outdoor objects (building shells with
null ParentCellId, outdoor scenery, outdoor creatures) keep the all-(-1) light
set ⇒ sun + ambient only = retail. The indoor "no sun" half is already handled by
the global sun-kill when the player is inside a cell (UpdateSunFromSky). No
dungeon regression: EnvCell statics get ParentCellId set (keep torches).

Divergence register: AP-37 (residual: acdream keys sun/torch on the object's own
cell + a per-frame player-inside sun-kill, vs retail's per-draw-stage useSunlight;
only matters for through-doorway look-ins). The round-1 CHECKPOINT got a RESOLVED
banner correcting the reach theory.

Tests: WbDrawDispatcherTorchGateTests (7), HoltburgTorchFalloffProbeTests (dat
dump). App 280/1skip, Core 1486/2skip green. Held at the visual gate — not merged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/architecture/retail-divergence-register.md

@@ -131,6 +131,7 @@ accepted-divergence entries (#96, #49, #50).
 | AP-33 | Interior-root look-in cells (**#124** sub-pass) draw their statics + DYNAMICS + emitters WHOLE — no per-part/per-object viewcone check; retail viewconeCheck's each vs the installed view (the **#131** portal closure: a server object in a look-in cell drew nowhere — dynamics-last culls cells absent from the main cone, and post-seal it z-fails anyway) | `src/AcDream.App/Rendering/RetailPViewRenderer.cs` (`DrawBuildingLookIns`) | The main viewcone has no entries for look-in cells; over-include is the safe direction (z-correct, repainted outside apertures by the root's shells); look-in cell counts are small (~1-3 cells) | A few wasted draws on content outside the doorway region (repainted); no under-draw direction remains | `viewconeCheck` 0x0054c250; nested `DrawCells` objects pc:432878 |
 | AP-34 | Landscape-stage alpha deferral is a TWO-PHASE slice split (statics-early / dynamics+particles+weather-late around the **#124** look-ins) + outdoor-root attached scene emitters moved to the post-frame pass, not retail's single deferred alpha flush. Residual: building exteriors' / outside-stage dynamics' own translucent MESH batches still draw within their stage draw call (before later stage content) | `src/AcDream.App/Rendering/RetailPViewRenderer.cs` (`DrawLandscapeThroughOutsideView` late loop) + `GameWindow` post-frame Scene pass | The MDI dispatcher draws translucency inside each Draw call; a faithful FlushAlphaList port needs a global deferred alpha list across all landscape draws — the split covers the user-visible cases (#131 portal swirl, #132 candle flame indoors + outdoors) | Translucent landscape content drawn early and screen-overlapped by content drawn later in the stage gets overpainted (no depth self-protection) — the portal-swirl/candle-flame class re-appears in the residual configurations | `D3DPolyRender::FlushAlphaList` (DrawCells pc:432722) |
 | AP-36 | Dungeon streaming gate triggers on the player's CURRENT cell being a sealed EnvCell (`CurrCell.IsEnv && !SeenOutside`), an approximation of ACE's full landblock `IsDungeon` (all-heights-zero + NumCells>0 + Buildings.Count==0). The retail BEHAVIOR (a dungeon loads no adjacent landblocks) is faithful — only the runtime TRIGGER is the cheap cell predicate instead of classifying the center landblock. **#135 pre-collapse:** at login/teleport the same collapse is triggered EARLY (the instant the streaming center is recentered onto the spawn/dest cell) via `IsSealedDungeonCell` reading the EnvCell **dat** `SeenOutside` flag — because the physics `CurrCell` is null until placement, which waits for hydration; without the early trigger the full 25×25 ocean-grid window loads then unloads (the ~30 s login FPS ramp) | `src/AcDream.App/Rendering/GameWindow.cs:6895` (per-frame predicate) + `:IsSealedDungeonCell` + `:OnLiveEntitySpawnedLocked`/`:OnLivePositionUpdated` (login/teleport pre-collapse hooks) + `src/AcDream.App/Streaming/StreamingController.cs` (collapse/expand/`PreCollapseToDungeon`) | The predicate is already computed for sun/sky gating (playerInsideCell) and exactly matches for sealed dungeons vs windowed building interiors (SeenOutside=true → not gated); no landblock re-classification needed. The dat-flag read is the same `EnvCellFlags.SeenOutside` the hydrated `ObjCell.SeenOutside` is built from (`EnvCell.cs:72`/`PhysicsDataCache.cs:224`), so the pre-collapse decision matches the eventual per-frame gate exactly | A dungeon cell that reports SeenOutside (an entrance cell open to the surface) briefly un-collapses and re-streams the window; a hypothetical windowless building back-room (IsEnv && !SeenOutside but HasBuildings) would wrongly collapse its outdoor neighbors; a sealed-dungeon entrance cell that is itself SeenOutside is simply MISSED by the early trigger and falls back to the existing late collapse (no worse than before #135) | ACE `LandblockManager.GetAdjacentIDs` (dungeons→empty) Landblock.cs:577-582; `IsDungeon` Landblock.cs:1264-1277 |
+| AP-37 | Per-object torch (point/spot) lighting is gated on the OBJECT's own cell: an object selects the static wall-torches ONLY when its `ParentCellId` is an EnvCell (`(id & 0xFFFF) >= 0x0100`); outdoor objects (building exterior shells with null ParentCellId, outdoor scenery, outdoor creatures) get the SUN + ambient and NO torches. This is the faithful port of retail's `useSunlight` gate — `DrawMeshInternal` (0x0059f398) calls `minimize_object_lighting` only `if (Render::useSunlight == 0)`, and the outdoor landscape stage runs `useSunlightSet(1)` (`PView::DrawCells` 0x005a485a, before `LScape::draw`) so outdoor objects are never torch-lit (closes the Holtburg meeting-hall facade torch-flood — A7 Fix D round 2, the dat's intensity-100 `falloff 6` orange torches were washing the exterior shell). **Residual approximation:** the sun/no-sun half is a per-FRAME global keyed on the PLAYER being inside a cell (`UpdateSunFromSky` zeroes the sun when `playerInsideCell`), NOT retail's per-draw-STAGE `useSunlight` toggle. So a mixed-stage frame (standing in a doorway / look-in) lights through-aperture objects with the player's regime, not the object's stage regime | `src/AcDream.App/Rendering/Wb/WbDrawDispatcher.cs` (`IndoorObjectReceivesTorches` + `ComputeEntityLightSet`); sun half `src/AcDream.App/Rendering/GameWindow.cs:10421` (`UpdateSunFromSky`) | The visible case — player OUTSIDE, looking at an outdoor building/scenery — is now exactly faithful (sun+ambient, no torches); player INSIDE a cell gets torches with the sun globally killed = faithful indoor regime. Cross-aperture mismatch only affects objects seen THROUGH a doorway from the other lighting context | A through-aperture interior object viewed from outside gets the sun (player outside) instead of retail's indoor torches-no-sun; an outdoor object viewed from inside gets no sun (player inside) instead of retail's sunlit outside stage — doorway/look-in frames only, not the standalone outdoor or indoor case | `useSunlight` gate `DrawMeshInternal` 0x0059f398; `useSunlightSet` 0x0054d450; outside stage `PView::DrawCells` 0x005a485a (`useSunlightSet(1)`); `minimize_object_lighting` 0x0054d480; `config_hardware_light` Range=falloff×`rangeAdjust`(1.5) 0x0059ad30 |
 | AP-35 | Point/spot lights are now PER-VERTEX Gouraud (`pointContribution` ~line 153 of `mesh_modern.vert`) matching retail's `SetStaticLightingVertexColors` bake path. Half-Lambert wrap (`(1/1.5)·(N·D + 0.5·d)`) AND norm distance attenuation (`distsq>1 ? distsq·d : d`) ARE ported (A7 Fix A, `aa94ced`). Point-light sum clamped to [0,1] on its own accumulator before adding ambient+sun (A7 Fix D D-1, mirrors retail's per-vertex bake clamp). CPU oracle: `src/AcDream.Core/Lighting/LightBake.cs`, locked by `tests/AcDream.Core.Tests/Lighting/LightBakeConformanceTests.cs`. **Residual (two parts):** (a) acdream lights in-shader each frame (per-frame GPU evaluate); retail bakes into the vertex buffer ONCE — an architecture/performance difference; the wrap + norm + clamp formula is the same, but bake-once is cheaper for static geometry; (b) acdream's `SelectForObject` keeps only the 8 NEAREST reaching point/spot lights per object/cell (`MaxLightsPerObject=8`, see AP-16), whereas retail's bake sums ALL reaching static lights per vertex — a surface reached by >8 point lights is dimmer in acdream than retail's bake result (rare in practice; a room has a handful of torches) | `src/AcDream.App/Rendering/Shaders/mesh_modern.vert` (`pointContribution` ~line 153; wrap ~line 163; norm ~line 167; point-sum clamp line 210) | Per-vertex Gouraud + wrap + norm + clamp all match retail. The two residuals are: (a) per-frame GPU vs bake-once — architecture/perf only; (b) 8-light cap dimming when >8 lights reach one surface — rare. `LightInfoLoader.cs:81` folds static_light_factor 1.3 into Range | (a) A new frame-time consumer bypassing `accumulateLights` would need to replicate the wrap + norm formula; per-frame GPU re-evaluate has higher per-frame cost than bake for static geometry. (b) A densely lit scene (>8 torches reaching one wall) renders dimmer than retail — see AP-16 for the 8-cap ownership | `calc_point_light` 0x0059c8b0 (line 0x0059c9a2 ramp; 0x0059c925 wrap); `SetStaticLightingVertexColors` 0x0059cfe0; static_light_factor 0x00820e24 |
 
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