The AP-152 retail review (docs/research/2026-08-06-ap152-review-retail.md)
FAILED `4abd1b5e` and is right. `ShadowObjectRegistry.BuildFloodSpheres` took
each physics-BSP part's ROOT BOUNDING SPHERE RADIUS
(FlatCollisionAssetBuilder.cs:393 -> LiveEntityCollisionBuilder.cs:137) and
centred it on the PART ORIGIN (ShadowShapeBuilder.cs:194), discarding the root
sphere's own Origin.
Re-measured independently against the installed client_portal.dat, reproducing
the reviewer's numbers exactly: 376 of 973 physics-BSP parts have
|origin| > radius/2, worst 20.762 m on a 27.708 m sphere (gfx 0x010036DD,
Setup 0x0200129A). Over the 172 Setups AP-152 moved onto that path the emitted
flood FAILED TO CONTAIN the object's own BSP sphere for 170 of them (73
CylSphere-bearing, 97 Sphere-bearing), worst shortfall 9.911 m on Setup
0x02000255 — whose one part's sphere sits 9.911 m above the part origin — and
for 43 the post-AP-152 flood was strictly SMALLER than the pre-AP-152 one.
Indoor flooding is 3-D (CellTransit.cs:601 routes every id & 0xFFFF >= 0x0100
candidate through FindTransitCellsSphere), so a tall prop or door slab was
absent from EnvCells it physically occupies and therefore never a broadphase
candidate there (TransitionTypes.cs:3763 iterates only entries already in the
cell). That is the #98 / #168 class AP-152 exists to remove.
Retail, re-disassembled from the PDB-paired binary (check_exe_pdb.py MATCH,
CodeView GUID 9e847e2f-777c-4bd9-886c-22256bb87f32), every address resolved
back through named-retail/symbols.json:
CGfxObj::physics_sphere is [gfxobj+0x74] (physics_bsp is [+0x78], as
CPartArray::CacheHasPhysicsBSP @0x00518110 reads at 0x00518127), and
acclient pseudo-C 0x00534b5b assigns it BSPTREE::GetSphere(physics_bsp).
BSPTREE::GetSphere @0x005397e0
8b01 mov eax,[ecx] ; BSPTREE::root_node
83c004 add eax,4 ; past BSPNODE::vfptr -> CSphere sphere
So retail's per-part flood sphere IS the BSP root bounding sphere,
ORIGIN INCLUDED (acclient.h: BSPNODE { vfptr; CSphere sphere; ... },
CSphere { Vector3 center; float radius; } -> radius at +0xc).
CPhysicsObj::find_bbox_cell_list @0x00510fc0 adds the object's own cell and
then walks the PART ARRAY: 0x00511012 call 0x518160
(CPartArray::calc_cross_cells_static), which dispatches [edx+0x7c] with
(num_parts, parts, cellarray). Its EnvCell body,
CEnvCell::find_transit_cells @0x0052cae0:
0x0052cb31 mov edx,[eax+0x20] ; CPhysicsPart::gfxobj (CGfxObj**)
0x0052cb36 mov esi,[ecx+0x74] ; physics_sphere (else +0x90 drawing)
0x0052cb4c add eax,0x30 ; CPhysicsPart::pos
0x0052cb5a call Position::localtolocal ; transform the sphere CENTRE
0x0052cb65 fadd [esi+0xc] ; only NOW the radius
Retail transforms the centre through the part's own Position before it ever
touches the radius. Carrying the radius alone is not an approximation of
that; it is a different sphere.
Changes:
* `ShadowShape` gains `BoundsCenter` — the bounding sphere's centre in the
shape's own local frame, scaled like LocalPosition and Radius. Zero for
Cylinder/Sphere shapes, whose LocalPosition already IS their centre.
* `ShadowShapeBuilder.FromSetup` gains a `physicsBspBounds` resolver that
supplies radius AND centre from ONE call, replacing the placeholder radius
plus a downstream substitution. `LiveEntityCollisionBuilder` now holds a
single `Func<uint, FlatCollisionSphere?>` and derives its dispatch predicate
from it, so the gate and the geometry cannot disagree and the radius cannot
be taken while the origin is dropped. That split is what produced this bug;
it no longer exists.
* `FromLandblockBspParts` carries the centre too. A landblock-baked part array
is the same CPartArray walk, so stair runs, fences and rock clusters had the
identical defect. Both storage forms (flat BSP and the graph fallback) are
covered.
* `BuildFloodSpheres` places each sphere at
partWorldPos + rotate(BoundsCenter, partWorldRot), composed exactly as the
ShadowEntry rows are.
* The 10-sphere clamp now applies to the CYLSPHERE branch only. Retail's clamp
is inside CObjCell::find_cell_list @0x0052b9f0
(0x0052ba21 cmp eax,0xa / 0x0052ba28 mov ebp,0xa); the BSP walk has none and
the sorting-sphere overload @0x0052b990 takes one sphere. 7 installed Setups
carry more than 10 physics-BSP parts (max 49, Setup 0x02001A91) and their
tail parts were dropped from the flood entirely. Without this the new
containment assertion would have covered shapes production never floods
from.
Register. AP-155 was two divergences with different code paths, populations
and gates under one id; it is NARROWED to its static-publication half and its
flood half is split out as AP-156 WITH ITS DIRECTION CORRECTED. AP-155(b)
recorded the approximation as over-inclusive — "floods MORE cells rather than
fewer, the safe direction for membership" — and that false direction was the
stated reason the residual was safe to defer. It was under-inclusive for 170
of 172. AP-156 records the correction, this fix, and the one genuine residual:
acdream's sphere-vs-portal traversal where retail walks each part's sphere
against the cell's own portal planes. AP-155(b)'s "acdream approximates
retail's bounding BOX" was wrong too — find_bbox_cell_list forms no box.
AP-157 filed for the review's F4: retail's third branch floods from ONE
CPartArray::GetSortingSphere @0x00518b00 ([partArray+0x54]+0x70 =
CSetup::sorting_sphere; 4,154 of 5,935 installed Setups carry a non-zero one)
where acdream floods from every Sphere shape, and acdream's cylinder flood
ignores CylHeight. Deliberately NOT bundled here: different branch, disjoint
population, different live gate. Active AP rows 107 -> 109, literal count.
Tests. Both flood tests the review named substituted a CONCENTRIC Radius = 14f
at LocalPosition = Zero — the one configuration in which the defect cannot
appear. Every fixture is now off-centre by default, and
`FromSetup_CylSphereAndBspSetup_FloodsTheBspFootprint` drives the production
`physicsBspBounds` seam instead of hand-substituting. Five new facts: the
flood centres on BoundsCenter not the part origin; it rotates BoundsCenter by
the part rotation; it caps cylspheres at ten but never the BSP parts; the
landblock path carries the scaled centre in both storage forms; and an
installed-DAT containment sweep asserting every emitted BSP flood sphere
contains that part's real bounding sphere at entity scale 1.75, behind four
external controls — 973 parts, 376 off-centre, 172 affected, and 170
would-fail-if-the-origin-were-discarded, the last of which fails if the
population ever stops exercising the field.
Nine sabotages, each reverted and re-verified:
A drop BoundsCenter from the flood -> 3 Core
B rotate by entity rot, not part rot -> 1 Core (the rotation fact only)
C FromSetup discards the origin -> 1 Core + 2 App + 1 Content
(the shipped defect, now caught in three projects)
D drop entScale on BoundsCenter -> 2 App + 1 Content
E landblock flat branch drops the centre -> 1 Core
F landblock graph branch drops it -> 1 Core
G drop partScale on the landblock centre -> 1 Core
H re-apply the 10-cap to every branch -> 1 Core
I remove the cylsphere cap -> 1 Core
AP-152's own two sabotages re-run against this tree: the step-0 gate disabled
still reddens exactly its five facts with Headless 89/89 green, and
cylinder-first flooding still reddens exactly one.
Clean Release build after deleting all 44 bin/obj: 0 errors, 21 pre-existing
warnings. Complete suite 11,208 passed / 4 skipped / 0 failed, +5 on the
11,203 baseline at 4abd1b5e — Core 4264 -> 4268, Content 126 -> 127, App
unchanged (one rename, not an addition). No new skips.
NOT yet gated live. This moves shadow-cell membership for real objects, in
both directions, and the connected session must look for both: props and doors
that START blocking from a neighbouring cell (the 73 CylSphere+BSP Setups),
AND ones that STOP blocking (the 99 Sphere+BSP Setups can shrink; 43 shrink
below their pre-4abd1b5e size, which is the regression this fixes). Tall
indoor props and door slabs — the ones whose sphere sits metres above the part
origin — are where the change is largest.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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