fix(render): #113 root cause #2 - GfxObj meshes draw only DrawingBSP-referenced polys (the REAL phantom staircase)

The user gate + bisect overturned the coincident-cell attribution: the
phantom staircase persists in the PRE-session build (bisect screenshot at
the hall wall) and is drawn by the ENTITY pipeline, untouched by any clip.

Root cause (dat-proven, DumpHallModel_PolyFlagHistogram): retail renders a
GfxObj by TRAVERSING its drawing BSP (D3DPolyRender); polygons present in
the Polygons dictionary but referenced by NO DrawingBSP node are never
drawn - they are physics/no-draw geometry. The Holtburg meeting hall
(0x010014C3) keeps its exterior stair-ramp as dictionary polys 0+1: in
the PhysicsBSP (ACE walks The Sentry on it at z 117-118; invisible-but-
walkable in retail) but orphaned from the draw tree (true at ALL degrade
levels - the LOD theory is dead, Degrades[0] IS the base model). The hill
cottage (0x01000827) carries 8 such orphans. Our extraction iterated the
dictionary -> drew the collision skeleton: the wall staircase up close,
the flying stairs over the cottage roofline from afar (orphan ramp spans
world 221-232 at z 116-124.5; visible over the cottage roof from the west).

Fix: PrepareGfxObjMeshData filters to CollectDrawingBspPolygonIds(gfxObj)
when a drawing BSP exists; models without one draw everything (unchanged).
Physics untouched (collision keeps the full physics set - retail parity).
CellStruct extraction not touched (different conventions; no orphan
evidence there yet).

Dat-backed pins: Issue113DrawingBspFilterTests (hall orphans == 0+1,
cottage orphans == 0..7). Suites: App 226 / Core 1392 + the 4
pre-existing #99-era failures / UI 420 / Net 294.

Note: the earlier shell-clip enable (927fd8f, scoped 9ce335e) remains
correct and orthogonal - it crops interior CELL geometry to apertures
outdoors; this commit removes the phantom SHELL geometry at its source.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
Erik 2026-06-10 20:52:52 +02:00
parent 6c9bbce433
commit e46d3d9273
3 changed files with 202 additions and 1 deletions

View file

@ -671,6 +671,98 @@ public sealed class Issue113PhantomStairsDumpTests
return inside;
}
/// <summary>
/// Round 6 (post-bisect): the phantom stairs+walkway render in BOTH builds
/// (the clip only hid the at-wall part). Retail draws NONE of it on this
/// face. Discriminator: do the meeting-hall model's ramp polys carry
/// distinctive per-poly flags (Stippling / SidesType / surfaces) that
/// retail skips and our building-mesh extraction mishandles?
/// </summary>
[Fact]
public void DumpHallModel_PolyFlagHistogram()
{
var datDir = ConformanceDats.ResolveDatDir();
if (datDir is null) { _out.WriteLine("dats unavailable — skipped"); return; }
using var dats = new DatCollection(datDir, DatAccessType.Read);
foreach (uint mid in new uint[] { 0x010014C3u, 0x01000827u })
{
var gfx = dats.Get<DatReaderWriter.DBObjs.GfxObj>(mid)!;
_out.WriteLine($"=== model 0x{mid:X8}: Flags={gfx.Flags} polys={gfx.Polygons.Count} physPolys={gfx.PhysicsPolygons?.Count ?? 0} ===");
var hist = new Dictionary<string, (int N, int Ramps)>();
foreach (var kv in gfx.Polygons)
{
var poly = kv.Value;
var pts = ResolveLocalPoly(gfx, poly);
if (pts is null) continue;
var n = NewellNormal(pts);
bool ramp = n != Vector3.Zero && MathF.Abs(n.Z) > 0.15f && MathF.Abs(n.Z) <= 0.9f;
string key = $"stip={poly.Stippling} sides={poly.SidesType} posSurf={poly.PosSurface} negSurf={poly.NegSurface}";
var e = hist.TryGetValue(key, out var v) ? v : (N: 0, Ramps: 0);
hist[key] = (e.N + 1, e.Ramps + (ramp ? 1 : 0));
}
foreach (var (key, v) in hist.OrderByDescending(k => k.Value.N))
_out.WriteLine($" [{v.N,3} polys / {v.Ramps,3} ramps] {key}");
if (gfx.PhysicsPolygons is not null && gfx.PhysicsPolygons.Count > 0)
{
int shared = gfx.Polygons.Keys.Count(k => gfx.PhysicsPolygons.ContainsKey(k));
_out.WriteLine($" physPoly ids shared with render polys: {shared}/{gfx.Polygons.Count}");
}
// Drawing-BSP coverage: retail draws a GfxObj by TRAVERSING the
// drawing BSP; polys absent from every BSP node's Polygons list are
// never drawn (orphans = physics/legacy geometry). Our extraction
// iterates the Polygons dictionary directly — it draws orphans.
if (gfx.DrawingBSP?.Root is not null)
{
var referenced = new HashSet<ushort>();
void Walk(DatReaderWriter.Types.DrawingBSPNode? node)
{
if (node is null) return;
if (node.Polygons is not null)
foreach (var pid in node.Polygons) referenced.Add((ushort)pid);
Walk(node.PosNode);
Walk(node.NegNode);
}
Walk(gfx.DrawingBSP.Root);
var orphans = gfx.Polygons.Keys.Where(k => !referenced.Contains(k)).OrderBy(k => k).ToList();
_out.WriteLine($" drawingBSP referenced={referenced.Count} dictPolys={gfx.Polygons.Count} ORPHANS={orphans.Count}");
int orphanRamps = 0; var omin = new Vector3(float.MaxValue); var omax = new Vector3(float.MinValue);
foreach (var pid in orphans)
{
var pts = ResolveLocalPoly(gfx, gfx.Polygons[pid]);
if (pts is null) continue;
foreach (var p in pts) { omin = Vector3.Min(omin, p); omax = Vector3.Max(omax, p); }
var n = NewellNormal(pts);
if (n != Vector3.Zero && MathF.Abs(n.Z) > 0.15f && MathF.Abs(n.Z) <= 0.9f) orphanRamps++;
}
if (orphans.Count > 0)
_out.WriteLine($" orphan stats: ramps={orphanRamps} AABB=({omin.X:F1},{omin.Y:F1},{omin.Z:F1})..({omax.X:F1},{omax.Y:F1},{omax.Z:F1}) ids=[{string.Join(",", orphans.Take(40))}]");
}
else
{
_out.WriteLine(" drawingBSP: NULL");
}
// Degrade chain: retail draws Degrades[0] (close detail), never the
// base, when a table exists (GfxObjDegradeResolver doc; #47).
if (gfx.Flags.HasFlag(DatReaderWriter.Enums.GfxObjFlags.HasDIDDegrade) && gfx.DIDDegrade != 0)
{
var ddi = dats.Get<DatReaderWriter.DBObjs.GfxObjDegradeInfo>(gfx.DIDDegrade);
if (ddi is null) { _out.WriteLine($" DIDDegrade=0x{gfx.DIDDegrade:X8} MISSING"); continue; }
_out.WriteLine($" DIDDegrade=0x{gfx.DIDDegrade:X8} entries={ddi.Degrades.Count}");
foreach (var d in ddi.Degrades)
{
_out.WriteLine($" degrade id=0x{d.Id:X8}");
ScanGfxStairs(dats, (uint)d.Id, $" -> ramp scan 0x{d.Id:X8}");
}
}
}
}
private void ScanModelStairs(DatCollection dats, uint modelId)
{
if ((modelId & 0xFF000000u) == 0x01000000u)