The "stuck in falling animation against walls" live-test bug (intermittent,
hard to recover from). Two compounding issues, fixed at both layers.
(1) DoStepUp cleared CollisionInfo.ContactPlaneValid unconditionally at
the start of step-up. On step-up FAILURE, RestoreCheckPos restored
the position but the contact plane stayed cleared. Added a save/
restore around the clear so a failed step-up returns the mover to
its pre-attempt grounded state.
(2) ValidateTransition propagated the current frame's invalid contact
state into LastKnownContactPlane via:
ci.LastKnownContactPlaneValid = ci.ContactPlaneValid
This destroyed the prior frame's ground memory whenever the current
contact was momentarily lost (StepUpSlide clears ContactPlane).
Changed to: only OVERWRITE LastKnown when current is valid.
(3) The same ValidateTransition then set
oi.State &= ~(Contact | OnWalkable)
when ContactPlaneValid was false, even if LastKnown was still
valid. Added an "else if (LastKnownContactPlaneValid)" branch that
sets Contact + OnWalkable from LastKnown so the animation system
sees the mover as grounded.
Combined effect: walking into a too-tall wall now consistently slides
along the wall without ever flickering to the falling animation. The
mover's grounded state survives transient ContactPlane invalidation
during the step-up retry cycle.
Retail's `transitional_insert` has different upstream invariants that
keep ContactPlane valid more often, so retail doesn't need the
acdream-specific LastKnown fallback path. ACE has the same pattern as
retail; acdream's per-frame Resolve architecture exposes the gap that
this fix closes.
Tests:
- New D1 regression test: grounded mover into too-tall wall — must
end frame with grounded state preserved.
- New D2 regression test: same scenario — execution time bounded
(<100ms) to catch any future recursion issues.
Files:
- TransitionTypes.cs DoStepUp: save+restore ContactPlane around step-up
- TransitionTypes.cs ValidateTransition: preserve LastKnown + grounded
state from last-known when current is invalid
- BSPStepUpTests.cs: D1, D2 regression tests
Test count 825 → 825 (D1+D2 added in L.2.3 patch series). Build clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>