AD-10 claims the remote slope projection is "relocated" out of the sweep
because "remote bodies don't run a full local transition sweep". That
justification is false at HEAD: RuntimeRemotePhysicsUpdater.Tick calls
PhysicsEngine.ResolveWithTransition with the remote's own body, and that
sweep runs acdream's verbatim port of CTransition::adjust_offset
(0x0050a370, pc:272271-272393) once per sub-step. So the boundary
projection is an EXTRA layer, not a relocation — and whether it is doing
anything the sweep does not is a measurement, never an argument.
This commit builds the fixture for that measurement and changes no
production code.
RuntimeRemoteSteepContactSlideTests' private Harness is extracted to
RemoteRampHarness so the new tests share it instead of cloning ~180 lines.
The extraction is behaviour-preserving; its only additions are the
fixture's own TerrainSurface (so an assertion about "is the body on the
surface" is answered by the surface geometry rather than by
re-implementing what the code under test computed), a SurfaceZ helper, and
a Tick overload that supplies a per-frame body-local root displacement —
the locomotion-cycle push a running remote actually carries. All ten Bug B
tests pass unchanged against it.
RuntimeRemoteSlopeProjectionTests then drives the production tick 30 ticks
down a 31-degree walkable ramp and asserts, on EVERY tick rather than at
the end, that the body's root stays within 5 mm of its settled offset from
the terrain beneath it. A staircase catching up on the final tick would
pass a start/end comparison; 30 unprojected ticks accumulate ~1.8 m.
Sabotage results, all from clean builds (bin/obj deleted), reported in
both directions:
* Discard the sweep's answer (Body.Position = postIntegratePos instead
of resolveResult.Position): RED at tick 1, body 0.05999 m off the
surface. This is the tracking test's discriminating sabotage.
* Flatten the ramp to gradient 0: RED on the anti-vacuity guard
(dz = 0.0000 m). That guard exists because the tracking assertion
passes trivially on flat ground, where Z never has to move.
* Short-circuit Transition.AdjustOffset to `return offset;`: GREEN.
Recorded, not hidden — it is the reason the contract's proposed T1
sabotage was rejected. On terrain the sweep has a SECOND independent
way to plant Z: ValidateWalkable's push-out re-seats the sphere at its
natural resting distance from the terrain plane every sub-step.
Removing the step-down probe as well does not change it either
(measured). The tests therefore assert the OUTCOME the projection
exists for, and say in their own doc comments that they are not unit
tests of adjust_offset and must not be cited as such.
One test the contract asked for is deliberately absent. An uphill
counterpart was written, passed, and was then found VACUOUS: on this
fixture ResolveWithTransition returns ok=False for uphill motion and the
body does not move at all, so it "tracked the surface" by standing still.
That finding is filed separately rather than shipped as a green test.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A remote observed in acdream landed on a sloped roof and froze; the server slid
on, the gap passed AP-87's 4 m threshold, and the body snapped — the visible
blip. Live probe capture, two adjacent ticks 63 ms apart:
t=88420671 rsInContact=True rsOnWalkable=False rsIsOnGround=True
bodyCpNz=0.6097 floorZ=0.6642 steep=True gravity=True
vel=(2.146,2.264,-3.549)
t=88420734 contact=True onWalkable=True <- forced against the sweep
gravity=False <- cleared
velBeforeZero=(2.146,2.264,0.000)
moved=0.0000 <- and every tick after
The roof is 52.4 degrees against a 48.4 degree limit, so acdream's classifier
was CORRECT and was then overruled. Four independent links each froze the body
on their own: a per-tick force of Contact|OnWalkable, a per-tick velocity zero,
a Gravity clear at landing, and a landing edge testing IsOnGround
(= inContact || ...) instead of OnWalkable. The tick called
HandleAllCollisions alone — the tail of SetPositionInternal without its prefix.
Retail simulates remotes locally and derives these bits rather than asserting
them: CPhysics::UseTime @0x00509950 iterates the whole object table;
update_object @0x00515D10 gates only on parent/cell/FROZEN with no
is_player fork; SetPositionInternal @0x00515330 sets CONTACT from
contact_plane_valid @0x00515430 and ON_WALKABLE from contact_plane.N.z vs
floor_z @0x00515465-@0x0051548E before handle_all_collisions @0x005154FE;
set_on_walkable @0x00511310 fires HitGround @0x00511364 / LeaveGround
@0x00511346 edge-triggered with no ownership gate; calc_acceleration
@0x00510950 zeroes only when CONTACT && ON_WALKABLE && !Sledding @0x0051096B;
calc_friction @0x0050EE70 returns at its first line when ON_WALKABLE is clear.
acdream had copied retail's airborne no-op WITHOUT retail's local simulation.
The fix is mostly deletion: stop forging the transients, stop discarding the
authoritative velocity, stop clearing Gravity, and route the remote tick
through the same SetPositionInternal commit TickHidden and the local player
already use, with the landing edge derived from the sweep's own OnWalkable.
AP-87's threshold and conditions and InterpolationManager's node_fail_counter
snap-to-tail are deliberately untouched — this removes the CAUSE of the
divergence rather than weakening the backstop.
Cross-checked against ACE: its only creature-side VectorUpdate emitters are the
jump broadcast and spell projectiles, so integrating the wire velocity cannot
double-move a walking remote; and PhysicsGlobals.DefaultState already carries
Gravity, so deleting the manufactured State |= Gravity is safe.
Register: AP-81 narrowed (its GRAVITY half retired outright), AP-87 annotated,
AP-139 filed (the interpolation-queue clear on the landing edge), AP-140 filed
(the two routing gates select snap-vs-interpolate on walkability where retail
uses CONTACT — adjust_offset @0x00555D30 gates on transient_state & 1
@0x00555D52). AP-140's follow-up is deliberately shaped as "point the two gates
at Body.InContact", NOT "re-derive Airborne", which would perturb five writers
and collide with a pinned RemoteTeleportPlacementTests assertion.
Three gaps recorded in #32 rather than papered over: the new LeaveGround
dispatch is untested for chatter; a persistently !Ok transition can latch a
remote airborne; and — the visual-gate watch item — the deleted forge was a
blanket guarantee of Contact|OnWalkable, and contact_allows_move @0x00528dd0
silently refuses action animations without both, which is the literal root
cause of closed#270. Retail-correct on a steep face, a regression anywhere
else.
10 discriminating tests over a real PhysicsEngine landblock whose contact
normal Z is 0.61 against FloorZ 0.6642 — the live roof's exact relationship.
Suite 11,019 passed / 4 skipped / 0 failed. Includes the temporary
ACDREAM_PROBE_REMOTE_LANDING / ACDREAM_PROBE_REMOTE_SLIDE probe family that
produced the capture above; strip with the family.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Erik