cdb attached to retail at a Holtburg cottage door while user walked the
inside-out off-center scenario. Three trace iterations identified that
retail's collision-recording happens via SPHEREPATH::set_neg_poly_hit
(fires hundreds of times during inside-out walk), NOT via the more
obvious-named COLLISIONINFO setters (which fire 0 times). Apparatus
scripts at tools/cdb/door-inside-out-v[1-3].cdb + symbol-probe.cdb.
Our codebase has NegPolyHitDispatch defined but never called. The
downstream TransitionalInsert NegPolyHit handler was a stub. Two-part
fix landed:
1. BSPQuery.FindCollisions Path 5 (Contact branch) restructured —
distinguishes full hit (hit0 == true → StepSphereUp) from near-miss
(hit0 == false but hitPoly0 != null → NegPolyHitDispatch). Mirrors
retail BSPTREE::find_collisions at
acclient_2013_pseudo_c.txt:0053a630-0053a6fb.
2. Transition.TransitionalInsert NegPolyHit handler — dispatches to
step_up + step_up_slide (NegStepUp=true) or records collision
normal + returns Collided (NegStepUp=false). Mirrors retail
CTransition::transitional_insert at
acclient_2013_pseudo_c.txt:0050b7af-0050b7e6.
Tests: all 11 fix-relevant + regression tests pass including issue #98.
VISUAL VERIFICATION (user-driven inside-out off-center): still squeezes
through. Diagnostic [neg-poly-dispatch] probe shows ZERO hits in
production. The Path 5 restructuring doesn't surface NegPolyHit
because our SphereIntersectsPolyInternal only sets hitPoly on FULL
hits — retail's sphere_intersects_poly sets var_5c (closest polygon)
even on near-misses via BSP-traversal side effect.
Remaining fix (next session): add near-miss polygon recording to
SphereIntersectsPolyInternal. Once it sets hitPoly on near-miss BSP
traversal, the Path 5 NegPolyHit dispatch (this commit) will fire
and the TransitionalInsert handler (this commit) will block.
Full handoff with cdb trace table + next-step plan:
docs/research/2026-05-25-door-bug-cdb-retail-trace-findings.md
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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