ISSUES #83 Phase A1.6. Phase A1 gated the mesh-AABB-fallback path on
!_isLandblockStab, but Setup-derived CylSphere/Sphere/Radius-fallback
registrations (lines 5910-6005) still ran for stabs. A landblock stab
whose source is a Setup (0x02xxxxxx) with defined CylSpheres got BOTH
per-part BSP shadows AND a CylSphere shadow with id=entity.Id,
producing an invisible collision cylinder at the stab origin
alongside the correct BSP walls. User reported this as "thin air" hits
outside specific Holtburg buildings.
Retail's CBuildingObj uses BSP exclusively. Setup CylSphere/Sphere
data is for scenery (trees with trunk cylinders) and creatures.
Fix: extend A1's _isLandblockStab gate to wrap the Setup-derived
registration block (cylsphere, sphere, radius-fallback). One AND
clause on the outer `if (setup is not null)`.
Probe evidence (launch-a15-verify.utf8.log):
- 0xC0A9B45D (6 hits in outdoor cell 0xA9B40029) — Setup CylSphere on
stab. src=0x020002FC. Pre-A1.5 it would also have been registered
in adjacent landcells.
- 0xC0A9B463 (2 hits) — Setup Sphere on stab. src=0x020000E6.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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