fix(#79/#93): mesh-empty hydration gate was dropping light-only fixtures

Root-caused via dat-truth inspection, not inference: the A7.L1 visible-
cell scoping fix (previous commit) had zero visual effect because the
Town Network fountain room (cell 0x00070144) registers ZERO lights of
its own — confirmed directly against the dat, not assumed. The room's
one dat-authored fixture, Setup 0x02000365 (a ceiling light 5m above the
fountain, warm color, intensity 100), has a single visual part that is a
#136-class runtime-hidden marker. Flattened mesh ref count: 0. GameWindow
's per-stab hydration loop treated meshRefs.Count==0 as "doesn't exist"
and dropped the whole entity before the Setup's Lights were ever read —
so a mesh-less "light attach point" fixture, a normal AC dat authoring
pattern, could never register. Retail's light registration (add_light,
CEnvCell::UnPack) is architecturally independent of a fixture's own mesh
visibility.

Fix: track the stab's Setup.Lights.Count alongside meshRefs during
hydration; keep the entity (with empty MeshRefs — nothing to draw, still
something to light) whenever either is nonzero. Extracted the decision
into EntityHydrationRules.ShouldKeepEntity (pure, unit-tested) since
GameWindow's hydration loop isn't independently testable. Confirmed no
downstream consumer assumes MeshRefs.Count >= 1 (WbDrawDispatcher already
guards on it before any indexing).

Core 2666+2skip / App 741+2skip / UI 425 / Net 385 green. Apparatus:
Issue93TownNetworkFountainRoomLightInspectionTests (dat-truth dump,
reusable for other rooms in this class).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
This commit is contained in:
Erik 2026-07-09 11:11:16 +02:00
parent d275ed554e
commit 9ebb206086
4 changed files with 221 additions and 2 deletions

View file

@ -7263,6 +7263,14 @@ public sealed class GameWindow : IDisposable
var meshRefs = new List<AcDream.Core.World.MeshRef>();
var interiorBounds = new AcDream.Core.Meshing.LocalBoundsAccumulator();
// #79/#93 (2026-07-09): a Setup-sourced stab whose sole visual part is a
// runtime-hidden marker (#136) flattens to zero mesh refs even though its
// Setup carries real Lights — a "light attach point" fixture (e.g. the Town
// Network fountain room's ceiling light, Setup 0x02000365). Track the dat
// Setup's Lights.Count here so the meshRefs==0 gate below doesn't also drop
// the entity that would otherwise carry those lights to the registration
// pass (GameWindow.cs ~7900).
int stabLightCount = 0;
if ((stab.Id & 0xFF000000u) == 0x01000000u)
{
var gfx = _dats.Get<DatReaderWriter.DBObjs.GfxObj>(stab.Id);
@ -7285,6 +7293,7 @@ public sealed class GameWindow : IDisposable
if (setup is not null)
{
_physicsDataCache.CacheSetup(stab.Id, setup);
stabLightCount = setup.Lights.Count;
var flat = AcDream.Core.Meshing.SetupMesh.Flatten(setup);
if (dumpStab)
{
@ -7321,12 +7330,14 @@ public sealed class GameWindow : IDisposable
}
}
if (meshRefs.Count == 0)
if (!AcDream.Core.Meshing.EntityHydrationRules.ShouldKeepEntity(meshRefs.Count, stabLightCount))
{
if (dumpStab)
Console.WriteLine($"[dump-entity] HYDRATE src=0x{stab.Id:X8} cell=0x{envCellId:X8} meshRefs=0 -> entity dropped");
Console.WriteLine($"[dump-entity] HYDRATE src=0x{stab.Id:X8} cell=0x{envCellId:X8} meshRefs=0 lights=0 -> entity dropped");
continue;
}
if (meshRefs.Count == 0 && dumpStab)
Console.WriteLine($"[dump-entity] HYDRATE src=0x{stab.Id:X8} cell=0x{envCellId:X8} meshRefs=0 lights={stabLightCount} -> KEPT as mesh-less light carrier");
// Stabs inside EnvCells are already in landblock-local coordinates
// (same space as LandBlockInfo.Objects stabs). Adding cellOrigin would