Rewrites src/AcDream.Core/Physics/InterpolationManager.cs from the spec
in docs/research/2026-05-04-l3-port/04-interp-manager.md. Public API
preserved (Vector3-returning AdjustOffset, Enqueue, Clear, IsActive,
Count) so PositionManager + GameWindow callers continue to compile;
internals are full retail spec.
Bug fixes vs prior port (audit 04-interp-manager.md § 7):
#1 progress_quantum accumulates dt (sum of frame deltas), not step
magnitude. Retail line 353140; the prior port's `+= step` made
the secondary stall ratio meaningless.
#3 Far-branch Enqueue (dist > AutonomyBlipDistance = 100m) sets
_failCount = StallFailCountThreshold + 1 = 4, so the next
AdjustOffset call's post-stall check fires an immediate blip-to-
tail snap. Retail line 352944. Prior port silently drifted
toward far targets at catch-up speed instead of teleporting.
#4 Secondary stall test ports the retail formula verbatim:
cumulative / progress_quantum / dt < CREATURE_FAILED_INTERPOLATION_PERCENTAGE.
Audit notes the units are 1/sec (likely Turbine bug or x87 FPU
misread by Binary Ninja) — mirrored byte-for-byte regardless.
#5 Tail-prune is a tail-walking loop, not a single-tail compare.
Multiple consecutive stale tail entries within DesiredDistance
(0.05 m) of the new target collapse together. Retail line 352977.
#6 Cap-eviction at the HEAD when count reaches 20 (already correct
in the prior port; verified).
New API: Enqueue gains an optional `currentBodyPosition` parameter so
the far-branch detection can reference the body when the queue is
empty. Backward-compatible (default null = pre-far-branch behavior).
UseTime collapsed into AdjustOffset's tail (post-stall blip check)
since acdream has no per-tick UseTime call separate from
adjust_offset; identical semantic outcome.
State fields renamed to retail names with sentinel values:
_frameCounter, _progressQuantum, _originalDistance (init = 999999f
sentinel per retail line 0x00555D30 ctor), _failCount.
Tests:
- 17/17 InterpolationManagerTests green.
- New test Enqueue_FarBranch_PrearmsImmediateBlipOnNextAdjustOffset
pins the bug #3 fix: enqueueing 150 m away triggers a same-tick
blip (delta length ≈ 150 m), and the queue clears.
Spec tree: 17 research docs (00–14) under docs/research/2026-05-04-l3-port/.
00-master-plan + 00-port-plan describe the 8-phase rollout. 01-per-tick,
03-up-routing, 04-interp-manager, 05-position-manager-and-partarray,
06-acdream-audit, 14-local-player-audit are the L.3 spec used by this
commit and the M2 follow-up.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Addresses code-quality review findings on commit f43f168:
C-1: Stall detection re-implemented to match retail (acclient lines
353071-353275). Tracks _progressQuantum (sum of step values per window)
+ _distanceAtWindowStart (set at window start). Primary check:
cumulative_progress < MIN_DISTANCE_TO_REACH_POSITION (0.20m absolute).
Secondary check: cumulative_progress / _progressQuantum < 0.30.
Either failing increments fail counter; blip-to-tail at >3 consecutive
fails (already correct).
C-2: Renamed StallFailCountForBlip -> StallFailCountThreshold with
clearer XML doc explaining the > vs >= semantics (blip fires when fail
count EXCEEDS the threshold, i.e. on the 4th consecutive failed window).
I-1: _haveBaselineDistance sentinel prevents first-window false
positive that was triggering spurious fails on every new motion sequence
(old code defaulted _distanceAtWindowStart to 0, making cumulative
progress always negative on frame 5).
I-3: dt <= 0 || NaN guard at AdjustOffset entry prevents NaN
propagation into PhysicsBody.Position.
I-4: Internal field renames for clarity:
_failFrameCounter -> _framesSinceLastStallCheck
_failDistanceLastCheck -> merged into _distanceAtWindowStart
I-5: Added internal Count property + InternalsVisibleTo (via
AssemblyAttribute in .csproj) so Enqueue_DropsOldestWhenAtCap20
actually verifies cap enforcement. Added assertion that head is the
second-enqueued position after overflow.
3 new tests (AdjustOffset_FirstWindow_DoesNotFalseFail,
AdjustOffset_DtZeroOrNegative_ReturnsZero,
Enqueue_AtCap20_HeadIsSecondOriginal), 16 total. All green.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Pure-data class + 13 unit tests.
Ports retail's CPhysicsObj::InterpolateTo (acclient @ 0x005104F0)
and InterpolationManager::adjust_offset (@ 0x00555D30) — FIFO position-
waypoint queue (cap 20) + per-frame catch-up math walking the body
toward the head node at 2 × motion-table-max-speed (clamped, with
7.5 m/s fallback). Reach @ 0.05m. Duplicate-prune @ 0.05m.
Stall detection: every 5 frames; if progress < 30% of expected,
increment fail counter; > 3 fails → blip-to-TAIL (resolved via
decomp dive of UseTime @ 0x00555F20: tail_ is the snap target,
not head_).
Constants verified from binary at named addresses (not guesses):
MAX_INTERPOLATED_VELOCITY_MOD=2.0, MAX_INTERPOLATED_VELOCITY=7.5,
MIN_DISTANCE_TO_REACH_POSITION=0.20, DESIRED_DISTANCE=0.05.
Composed into RemoteMotion in subsequent task; not yet used.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
