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>
Attribution (dat-evidenced, supersedes the misplaced-cell hypothesis):
the phantom staircase is the Holtburg MEETING HALL (AAB3 building[0],
model 0x010014C3 at AAB3-local (36,84,116)), NOT an A9B3 building - the
user stood at the A9B3/AAB3 boundary (cell-transit trail in
issue112-gate1.log) and clicked through the hall to the NPC behind it.
The hall's interior stair cells (0x100..0x106, ring climbing z 116->124.5
to the deck hatch) have geometry coincident with the shell's west wall
(both at local x=29.0). Our outdoor per-building flood admits them with
CORRECT tight clip regions (4-6 planes, door-aperture NDC boxes -
Issue113MeetingHallFloodTests proves it), but DrawEnvCellShells drew them
WHOLE: mesh_modern.vert writes gl_ClipDistance from the routed CellClip
slot, and gl_ClipDistance is ignored unless GL_CLIP_DISTANCEi is enabled -
which no caller ever did for the shell pass (born inert in 1405dd8).
Interior staircase painted across the exterior wall; unpickable because
it is cell geometry, not an entity.
Retail oracle: cell geometry IS clipped to the accumulated portal view -
Render::set_view (:343750) installs the view polygon edge planes,
DrawEnvCell submits every cell polygon with planeMask=0xffffffff (:427922)
through ACRender::polyClipFinish. Characters/meshes are NOT poly-clipped
(viewconeCheck path) - entity routing stays cleared, comment scoped.
Fix: enable GL_CLIP_DISTANCE0..7 around exactly the shell pass
(self-contained per feedback_render_self_contained_gl_state; no early-outs
between set and restore). Slot-0 fallback slices (>8-plane regions) still
draw pass-all - the assembler's scissor fallback remains unimplemented and
documented; the new flood test pins 0 such slices at the hall.
Refuted along the way (full evidence in Issue113PhantomStairsDumpTests):
- ONE misplaced interior EnvCell unifying #113+#112+collision gaps: all 17
A9B3 cottage cells share an identical dat Position (nothing to misplace);
the #112 gap is a real 20cm doorway micro-gap 0.23m outside threshold
cell 0x104 (straddles its exterior portal plane at foot radius 0.48);
missing object collision remains #99/A6.P4.
- A9B3 dat content near the spot: no stair geometry in shell (balcony at
z119 + turret roof only), cells (flat 116/118.8), statics, or stabs.
Tests: Core 1389 green (+6 dump facts) / App 224 (+1 flood replay) /
UI 420 / Net 294; pre-existing 4 #99-era failures unchanged.
Visual gate pending: user re-check of the hall west face vs retail.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
