Four tests were asserting pre-change behavior after intentional production
changes:
#2 BSPStepUpTests.C3_Path6_AirborneMoverHitsSteepSlope_SetsCollide
b1af56e (L.4, 2026-04-30) added a steep-normal gate in Path 6 that
fires BEFORE SetCollide. Airborne sphere hitting steep poly now returns
Slid + Collide=false (slide-tangent interim fix). Updated assertion +
renamed to ReturnsSlid.
#7 PlayerMovementControllerTests.Update_ForwardInput_MovesInFacingDirection
#8 DispatcherToMovementIntegrationTests.Dispatcher_W_held_produces_forward_motion
235de33 (L.5, 2026-04-30) added _physicsAccum accumulator gate: a single
Update(1.0f) only integrates one MaxQuantum (0.1s ~ 0.312m at walk speed),
not the full 1s. Time is carried in accumulator (not dropped). Fixed both
tests to loop Update(MaxQuantum) for ~11 ticks to accumulate >2m of real
forward motion, preserving the original distance-threshold assertion intent.
#9 PositionManagerTests.ComputeOffset_BothActive_Combined
842dfcd (L.3.2, 2026-05-03) changed ComputeOffset from additive
(rootMotion + correction) to replace semantics: when AdjustOffset returns
non-zero, it REPLACES root motion (retail Frame::operator= semantics).
offset.Y = 0 (not 0.4); root motion is dropped when catch-up engages.
Updated assertion and renamed to CorrectionReplacesRootMotion.
Suite: 9 failures → 5 (only the 5 known-bug tests remain red).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Grounded player remotes were showing a ~5 Hz Z staircase when running
up/down slopes — the rate of server UpdatePositions. Body Z stayed flat
between UPs, then ramped over ~100ms during the queue-active chase to
each new server position, then went flat again until the next UP.
Diagnosis (no diagnostic needed — the math is unambiguous):
PositionManager.ComputeOffset has two modes via
InterpolationManager.AdjustOffset:
- Queue active (body chasing a waypoint): returns
`(head − body) / dist × min(catchUpSpeed × dt, dist)`. 3D direction,
Z follows server's reported Z naturally.
- Queue empty / head-reached (within DESIRED_DISTANCE = 0.05m of the
most recent UP): returns Vector3.Zero. ComputeOffset falls back to
`seqVel × dt rotated into world` — pure animation root motion. Every
locomotion cycle bakes Z=0 in body-local, so the world result has
Z=0 too. XY advances at the running pace; Z stays at the last UP.
For a runner at maxSpeed ≈ 4 m/s with catchUpSpeed = 2× = 8 m/s and
server UPs at ~5 Hz, body covers ~0.8m per UP, chases for ~100ms
(queue-active 3D path, Z ramps), then sits in seqVel-only mode for
~100ms (Z flat) until the next UP. Visible as a 5 Hz Z staircase.
Fix mirrors retail's CTransition::adjust_offset contact-plane projection
(named-retail acclient_2013_pseudo_c.txt:272296-272346) for grounded
motion, applied at the queue-empty boundary instead of inside the sweep:
PositionManager.ComputeOffset gains an optional Vector3? terrainNormal.
When the seqVel-only fallback runs AND a non-trivial terrain normal is
supplied, project rootMotionWorld onto the plane:
result = rootMotionWorld − N × dot(rootMotionWorld, N)
Anim XY motion gains a corresponding Z component proportional to slope
angle × forward speed, so body Z follows the terrain mesh between UPs.
No-op on flat ground (N ≈ +Z, dot ≈ 0); cannot regress L.3 M2's
flat-ground verification.
GameWindow.TickAnimations grounded-remote path samples
PhysicsEngine.SampleTerrainNormal at the body's current XY each tick
and passes it to ComputeOffset. SampleTerrainNormal is a thin public
wrapper over the existing internal SampleTerrainWalkable that returns
just the plane normal (no need to expose the internal sample shape).
Diagnostic: ACDREAM_SLOPE_DIAG=1 prints a per-tick [SLOPE] line with
guid, body Z before/after, offset, queue active flag, and the sampled
plane Nz so we can grep before/after the fix and confirm Z changes
continuously between UPs on slopes.
Tests: PositionManagerTests gains two cases:
- slope projection: 30° east-tilted plane, body running due east at
4 m/s for 1s → expect (3.0, 0, −1.732) (descends along slope, not
flat). Math: dot(seqVel, N) = 2.0 → result = (4,0,0) − (0.5,0,0.866)
× 2.0 = (3.0, 0, −1.732).
- flat-ground no-op: N = +Z, expect identical Y-only motion as the
pre-fix behavior.
Build green. 357 pass / 6 pre-existing fail (same set as ec59a08;
verified by stashing this change). The pre-existing
`ComputeOffset_BothActive_Combined` failure reflects an outdated
additive-design test docstring; the M2 commit (40d88b9) deliberately
changed the implementation to REPLACE semantics to fix the prior
3×-server-pace overshoot.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
