Implements the rest of the §6.2 lifecycle on top of 5.1's state machine.
5.3 kickoff: the server resets every body and broadcasts the RESULTING
transforms, never a seed - §1's locked decision, because shared-seed
determinism needs both sides to consume the RNG stream in identical
order forever and the first randf() added to the reset path desyncs
silently. Countdown is derived from server_tick on both peers, and a
kickoff that lands after its own resume tick applies immediately and
skips the countdown rather than scheduling into the past.
5.4 goals: goal_scored(scoring_team, score, goal_tick, resume_tick).
Score is authoritative at sensor time, before any presentation. The
reset moved OUT of the sensor path and into the kickoff at resume_tick,
which is what stops the server resetting while clients are still
mid-celebration. Engine.time_scale is never touched.
5.2 clock: tick-derived, no Timer and no _process polling. The goal
pause shifts the absolute end_tick by (resume_tick - goal_tick) rather
than pausing anything, so no float drift accumulates across goals.
5.5 full time: clock expiry -> FULL_TIME -> sudden death on a draw or
RESULTS, golden goal in overtime, then LOBBY on both peers - clients
return to the lobby, not the main menu. get_tree().paused is never used.
Four bugs found and fixed while building this, each by a failing run
rather than by inspection:
- Tick order was load-bearing: _update_kickoff_countdown() clears the
same _kickoff_resume_tick that _update_match_state() reads to leave
WARMUP, so running the countdown first wiped the transition condition
and the match sat frozen in WARMUP forever.
- _apply_match_state resets _state_deadline_tick on every transition, so
a GOAL_PAUSE deadline assigned before _set_match_state was wiped and
the match never resumed. Deadlines are now owned by _apply_match_state.
- Freezing "all bodies" is wrong on a client. Remote ships and the ball
are permanently FREEZE_MODE_KINEMATIC and transform-driven; freezing
them all unfroze the remote ones on the way back out, so they fell
under gravity while the interpolator fought them - 210 hard snaps and
an infinite p99. A client now freezes only the one body it simulates.
- A frozen body never runs _integrate_forces, so the queued kickoff
teleport was stranded by an immediate set_deferred("freeze", true).
Freeze now happens on a strictly later tick, the same pattern Phase 2
used for _pending_reset_gen_bump_tick.
Prediction and reconciliation are suspended while the match is not live:
during a countdown or goal pause the local ship is frozen on both peers,
and running delta transport over those frozen states produced a p95
position error of 2.4e10 m. Input keeps flowing so the server's jitter
buffer does not starve into `stalled`.
Also fixed: a kickoff can arrive before match_config, and body order is
slot order - applying it early placed the BALL at positions[0], on top
of the first ship, which the ball-cam reported as "target vector can't
be zero" 95 times. It is now held until the roster exists.
Test changes: the ball-contact scenario steered by a hand-tuned fixed
heading, which 5.3 broke because kickoff applies KICKOFF_YAW_JITTER - it
flew past the ball in 3/3 runs. It now closes the loop on the actual
bearing using real input actions. Assertions that read a frozen ship
(freeze, thrust) are gated on the match being live, and the hooks now
survive the scene teardown at RESULTS instead of hanging on freed
objects for the full timeout.
Regression: 81 unit tests; free-flight LAN p99 0.143m and 80±20ms, both
0 hard snaps; transition gate 0.00%; ball contact 3/3; two-bot CI.
Closes Phase 4's outstanding action-sequence-correctness invariant, then
fixes two server-side bugs an adversarial review of that work uncovered.
Server simulation, bot observations, collision resources and tick rate are
unchanged: the server_physics_parity trace is byte-for-byte identical to
HEAD across 360 ticks including both ships' full observation vectors.
4.11 - prediction history filed under the ISSUING sequence
_send_local_input filed each post-step predicted state under the timeline's
estimate of the sequence the server would consume this tick, trailing
issuance by input_lead. The body had integrated the intent issued under
_input_seq, so predicted[S] held "state after the intent from now" while
the server's authority for S is "state after action(S)". They agree only
while the stick is still. Filing under _input_seq costs nothing: which
action the ship uses is decided in LocalNetShipController.get_action() and
is untouched.
Every prior Phase 4 gate held its input steady, and a steady input cannot
falsify a sequence label - the 60s runs honestly reported marker=0/3784.
New --exercise-input-transitions role toggles thrust every 6 ticks; it is
the only gate that can catch a label regression. Verified non-vacuous: the
old label fails it at 50%.
4.12 - issued-but-unsimulated sequences, and the release path
An attack (delta > 1) issues and sends several sequences for one local
physics step. Those gap sequences had no recorded prediction, so a server
ack of one reported missing_not_recorded - indistinguishable from ring
loss, costing a teleport and resync suppression several times a minute.
They are now recorded stateless via record_unsimulated() and answered with
a new "skip" decision mode. Free-flight hard snaps: 25/8/4 -> 0/0/0.
A release (delta == 0) re-recorded at the unchanged _input_seq, filing the
current intent under a sequence that went out carrying a different action;
LocalInputTimeline deliberately refuses to mutate an issued sequence, so
the ring contradicted the wire. Recording is now skipped on release ticks.
4.13 - two Phase 3 bugs silently killing player input
(a) InputJitterBuffer.consume() advanced last_applied_seq on every tick
including a starve. Since ingest() discards seq <= last_applied_seq, one
starve on a sequence the client had not sent yet stranded the stream one
ahead of arrivals permanently - both sides advancing in lockstep, every
honest packet discarded on arrival. The client's own input_lead release is
enough to trigger it, so input died for ~30 ticks roughly every 6.5s on a
clean LAN. Now only gives up on a sequence once strictly newer data proves
it lost. Silent-client stall and ring-overflow resync are unchanged.
(b) The seq-range guard bounded incoming seq against highest_ingested_seq,
which only advances inside ingest(), which that guard gates. After a ~2s
host hitch every packet was rejected forever with no diagnostic (600+
consecutive rejections reproduced via SIGSTOP). Third iteration of this
guard; each previous version bounded against a value only the accepted
path could advance. Adds an escape after 10 consecutive rejections, which
grants an attacker nothing the rate limiter does not already bound.
(c) The transitions gate reported PASS at 3.76% while input was completely
dead, because suppression stops _record_metrics - a worse outage yields
fewer samples and a LOWER rate. Now scales the required sample count with
run length and asserts the wire's server_stalled bit. Reverting both fixes
makes it fail at samples 292/600, server_stalled=true, input_lead=12.
Fixing (a) also explained a residual the review had already traced: 151 of
151 action-marker mismatches were the server repeating a stale action on a
starve, not a prediction defect. Marker is now 0.00% in all three
conditions (was 1.7-2.5%), and free-flight p99 improved to
0.141/0.168/0.154m from 0.170/0.176/0.184m.
Two pre-existing test defects fixed alongside: the ball gate asserted
RTT-masking on a link with no RTT (flaked 2 in 5; now asserted only at
rtt >= 20ms, 5/5 under latency), and the two-bot CI compared scores across
a 3-5s window (now polls the scores the server actually held; note
score_changed is emitted only on the client path).
QA: 72 unit tests; 60s free-flight at LAN/80+-20ms/5% loss; transition
gate in all three; 2.0s and 3.5s host-freeze recovery; ball contact x5;
two-bot CI x3; all three abuse roles; net/match_net/clock/lobby smokes.
Phase 4 sign-off still pending a human playtest at ~100ms RTT - the
milestone asks how it feels, which no gate here answers.
Lands the non-networked Phase 0 tasks from multiplayer-todo.md (ship/camera/
arena refactors, sim constants, background FPS handling) plus a first pass
at exposing graphics/performance settings (presets, resolution scaling,
vsync, FPS cap, perf overlay) and a GPU profiling harness for the
real-hardware follow-up in task 0.15b.
Josh Creek