Port CTransition::step_up (Path 5) and SPHEREPATH::set_collide (Path 6)
from the retail decomp, turning wall-slides into proper step-up climbs
and airborne-to-roof landings.
Path 5 (grounded mover hits polygon):
- StepSphereUp calls DoStepUp which runs DoStepDown with StepUp=true
- DoStepDown now includes the retail Placement validation step
(ACE Transition.cs:731-741) — sphere must not be inside solid geometry
after finding a contact plane; this correctly blocks the tall-wall case
- FindObjCollisions now allocates a local ShadowEntry list per call to
prevent "collection modified" exceptions when DoStepUp recurses back
through TransitionalInsert → FindObjCollisions
- BSPQuery.FindCollisions passes engine through to StepSphereUp
Path 6 (airborne mover hits polygon):
- SpherePath.SetCollide: saves backup pos, records StepUpNormal, sets
WalkInterp=1 — then returns Adjusted so TransitionalInsert retries
- SpherePath.StepUpSlide: clears ContactPlane, sets SlidingNormal for
the tall-wall fallback
- TransitionalInsert Collide branch: re-tests as Placement when
ContactPlaneValid; on failure restores backup and returns Collided
Test fixes (BSPStepUpTests.cs + BSPStepUpFixtures.cs):
- Tests use foot-position convention (CurPos = foot, sphere center =
CurPos + (0,0,r)); from/to corrected from sphere-center to foot coords
- MakeTestEngine terrainZ param: 0f for grounded tests (keeps Contact
state between sub-steps), -50f for airborne/roof tests
- to.X adjusted so sub-steps land sphere inside (not exactly touching)
the wall, avoiding the EPSILON-shrink false-negative edge case
- All 12 BSPStepUp tests now GREEN; full suite 823/823
Retail refs:
CTransition::step_up — acclient_2013_pseudo_c.txt:273099 / ACE:746
CTransition::step_down — acclient_2013_pseudo_c.txt:273069 / ACE:710
SPHEREPATH::set_collide — acclient_2013_pseudo_c.txt:321594 / ACE:279
CTransition::transitional_insert Collide — pseudo_c:273193 / ACE:891
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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