arcattackandClaude Fable 5
29035028fd
User report: lasers only visible on the window firing them. The peer's replicant emitters never learned the master fired. THE AUTHENTIC PIPE (decomp-verified): - FUN_0041c350 (the "beam keepalive" ServiceDischarge/ContinueDischarge call) does TWO things: queue the LOCAL deferred beam-effect callback (@0x4bac0c) on the app+0x34 manager -- our per-weapon render walk already plays that role -- and set the subsystem DIRTY bit, which maps to the 2007 engine's updateModel / ForceUpdate(). - Replication rides SUBSYSTEM UPDATE RECORDS inside the mech's update message: the roster walk already hands the entity's stream to every subsystem's PerformAndWatch; Simulation::WriteSimulationUpdate serializes each requested updateModel bit; Entity::UpdateMessageHandler routes received records by subsystemID to the subsystem's ReadUpdateRecord. All engine machinery -- the missing pieces were the Emitter's serialize/apply pair + the triggers. CORRECTIONS to the dormant task-33-era transcriptions (never exercised -- nothing ever set updateModel -- so the latent misreads never surfaced): - The weapon-family VTABLE SLOT MAP was swapped: slot 6 = ReadUpdateRecord, 7 = WriteUpdateRecord, 9 = TakeDamage (evidence: Mech hierarchy symmetry + body semantics; @004ba568 resolves an EntityID at rec+0x30 through the entity index -- record semantics, not Damage). Renamed across MechWeapon / Emitter / ProjectileWeapon; the real Emitter::TakeDamage @004bafc8 is undecoded (inherits MechWeapon for now). - Emitter/MechWeapon Write: `*record = 0x38/0x18` is the record LENGTH, not recordID; rec+0x30 is the TARGET's EntityID (GetEntityID()), not a colour -- the old `CopyColor(targetEntity+0x184)` was also a databinding trap. - OVERRIDE-SIGNATURE TRAP: the decls used each class's own shadowing UpdateRecord typedef as the param type, silently NOT overriding the engine virtual (the base ran instead; nothing would ever have serialized). Base-typed params (Simulation__UpdateRecord*), casts inside. - Emitter::ReadUpdateRecord reconstructed (@004ba568): target EntityID resolve (drop unknown non-null targets), MechWeapon alarm apply chain, beam fields. - ServiceDischarge/ContinueDischarge: ForceUpdate() per keepalive tick + one final record at beam end (turns the peer's beam off). - Mech::DrawWeaponBeams extracted from the player-only drive block so the walk runs for REPLICANTS (+ per-mech gun-port cache -- the process-wide statics would have served the player's segment pointers as the replicant's muzzles). VERIFIED 2-node: A fires 57 volleys -> 225 emitter records -> B applies all 225 -> B draws 414 beams (PPC blue / laser red, from A's replicant's own gun ports). Solo un-regressed (150 beams, kill chain, no crash). Also preserved: the full Mech::WriteUpdateRecord @0x4a0c2c recovery (reference/decomp/mech_writeupdate_004a0c2c.disasm.txt) with all 9 record types decoded (pose/alarm/leg-state+heat with the body-channel write-through re-sync, knockdown, death, impact, movementMode) -- transcription deferred; it replicates remote knockdown/death/heat and was not needed for beams. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
213 lines
17 KiB
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213 lines
17 KiB
Markdown
---
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id: multiplayer
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title: "Multiplayer — replication, netcode, the console"
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status: provisional
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source_sections: "PROGRESS_LOG.md §7 (Phase 7), §8 (P6); docs/HARD_PROBLEMS.md (P6)"
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related_topics: [wintesla-port, combat-damage, locomotion, decomp-reference]
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key_terms: [master, replicant, EGG, dead-reckon]
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open_questions:
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- "Cross-pod combat (damage to a replicant's master); replicant gait; pod-LAN config"
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---
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# Multiplayer
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Pod-to-pod networked play. The hard infrastructure exists (WinTesla replaced DOS `NETNUB` with a
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WinSock2 TCP stack); the work is integrating + smoke-testing it for BT. Full detail:
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`docs/PROGRESS_LOG.md §7, §8`; the problem writeup: `docs/HARD_PROBLEMS.md` (P6).
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## The stack (already reconstructed)
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- WinTesla replaced `NETNUB` with a **3446-line WinSock2 TCP** reimplementation (`MUNGA_L4/L4NET.CPP`,
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`SOCK_STREAM`/ReliableMode, zero SOCK_DGRAM); the master/replicant distributed-sim core
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(InterestManager/Entity/HostManager) is complete. So MP = integrate + smoke-test that stack (gated
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on P3 locomotion + P5 entity lifecycle + subsystem WAVEs). The rumored `L4NET.CPP:1853` send-size
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bug is DEAD CODE (`#if MESSAGE_BUFFERING`==0). [T2]
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## Master / replicant model
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- **[[master]]** = a locally-simulated entity (your mech + dummies); drives itself + EMITS update records.
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- **[[replicant]]** = a peer's mech, a local proxy; DeadReckons toward the master's replicated position.
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MUST `SetValidFlag()` at creation or every message defers forever ([[reconstruction-gotchas]] §9).
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## How a session forms
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`-net <port>` = networked mode (the pod listens on <port> for a CONSOLE, boots ConsoleOnly; game mesh
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= <port>+1). Solo (no `-net`) never touches WinSock. The mission egg's `[pilots]` section IS the
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roster (`pilot=ip[:port]` + a per-address page); each pod self-identifies by local-IP+game-port,
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connects to earlier pilots, listens for later ones — a deterministic full mesh; the mission loads when
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all connect. The **CONSOLE** (operator station — ABSENT from every archive) delivers the egg as chunked
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`ReceiveEggFileMessage` packets + the LAUNCH `RunMissionMessage`; **`tools/btconsole.py` is our console
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emulator** (⚠ `NotationFile::ReadText` expects NUL-SEPARATED lines). [T2]
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## Verified milestones (one box, two instances)
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- **P6 smoke test:** two instances share a world — console egg → TCP mesh → synchronized start →
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bidirectional entity replication (each renders its own mech + the peer's REPLICANT), 0 crashes.
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- **Movement replication:** A's mech WALKS on B's screen (the replicant tracks the master to ~1.5u via
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dead-reckoning). The authentic mission-start ladder runs (CreatingMission→…→RunningMission via the
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console LAUNCH). SIX bugs fixed to get here (dead-reckoner install, replicant-motion DeadReckon,
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master emission threshold, emission gated on RunningMission, the console-must-LAUNCH fact, replicant
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validity). [T2]
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- **Wire-format bug class found+fixed:** MakeMessages replicate RAW over TCP, so string payload must be
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INLINE (`char[N]` at the binary offsets), not a `const char*` pointer (garbage cross-pod). Check
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EVERY MakeMessage for pointer payloads. [T2]
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## Debug tooling (`BT_NET_TRACE`, permanent)
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`[net-tx]/[net-rx]` (L4NET), `[net-upd]` (update lookup), `[upd-repl]`, `[ent-exec]` (state ladder).
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Per-instance: `BT_LOG=<file>` + `BT_AFFINITY=<mask>` (CPU pin). Update stream ≈ 60 Hz × 144-byte
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records per moving master. [T2]
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## Cross-pod combat step 1+2 (task #46, 2026-07-09) [T2 findings]
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**Step 1 — target ANY peer mech: DONE + verified.** A live-mech registry (`BTRegisterMech`/
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`BTDeregisterMech` from the Mech ctor/dtor, btplayer.cpp) collects every Mech — player, dummy,
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AND peer replicants. The mech4 boresight world-pick now walks `BTGetTargetCandidates` (all mechs
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≠ shooter) and picks the CLOSEST the ray strikes, retargeting the whole fire/damage block from
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the solo `gEnemyMech` to the picked `hotTarget` (missile impact + projectile validation
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generalised via `BTIsRegisteredMech`). Verified one-box: instance A correctly enumerates B's
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mech as a live `ReplicantInstance` (inst=4), 20 zones, `ownerID=3`, alive. Solo un-regressed
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(pick→damage→kill chain clean).
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**Step 2 — cross-pod damage: SOLVED + verified end-to-end (task #47, 2026-07-09).** A one-line fix
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(`Mech::Make`) yields a full cross-pod KILL: instance A (host 2) shoots B's mech (host 3) dead over
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the network, B runs the death transition (wreck swap + explosion) on its own screen. [T2]
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**THE BUG (root cause): B's own MASTER mech was INVALID, so every dispatched network message to it was
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DEFERRED forever.** `Entity::Receive(Event*)` (ENTITY.cpp:165) does `if(!IsValid()) event->Defer();
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return;`. The reconstructed `Mech::Make` (mech.cpp) force-set `ValidFlag` ONLY for replicants (the P6
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bring-up hack for the partial MakeReady/CheckLoad handshake); a locally-created **master** never got
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validated. So A→B TakeDamage arrived, resolved to B's real master mech, Posted, drained to
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`Entity::Receive` — which saw `valid=0` and Deferred it. Handler never ran → 0 damage.
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**THE FIX:** `Mech::Make` now sets `ValidFlag` for the master too (`if (mech != 0) mech->SetValidFlag();`
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— the reconstructed ctor builds the whole mech synchronously, so it's safe). NOTHING ELSE changed: the
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targeting, the virtual `victim->Dispatch`, the reroute, the wire, the receive, and the id resolution
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were all already correct. Solo un-regressed (the solo enemy was already force-valid via btplayer:839;
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the change only ADDS `ValidFlag`).
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**Verified full path** (2-node one-box, `BT_MP_FORCE_DMG` on A firing at B's replicant once/sec):
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1. A: `victim->Dispatch(&td)` (VIRTUAL — the real beam path) → `Entity::Dispatch` reads `inst=Replicant`,
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stamps `entityID=3:22` (B's master id), `if(ReplicantInstance) SendMessage(ownerID=3, EntityManagerClientID)`.
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2. Wire: `NetworkManager::Send` (L4NET.CPP:1062) → `send()` to host 3 (online).
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3. B: `ReceiveNetworkPacket` (NTTMGR.cpp:107) → `GetEntityPointer(3:22)` = `entityIndexSocket.Find`
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(HOSTMGR.h:270) → resolves to B's **master mech (classID 3001=0xBB9)** → `Post(EntityManagerEventPriority)`.
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4. B: event drains → `Entity::Receive` (now `valid=1`) → `Mech::TakeDamageMessageHandler` (mech.cpp:548)
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→ invalidZone (−1) cylinder lookup → zone damage. ~36 hits × 12 → B's mech DESTROYED + death transition.
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**Two prior mis-diagnoses corrected — both were the WRONG messageID.** `Entity::TakeDamageMessageID` is
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**18**, NOT 21 (confirmed at runtime: `td.msgID=18`, so `Simulation::NextMessageID`=3, not 6). Every
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earlier probe filtered `msgID==21`, so it NEVER matched a real
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TakeDamage — the stray `msgID=21` hits it caught were an unrelated message, and correlating their `3:19` /
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`classID 48` against the real `3:22` TakeDamage produced two phantom root causes: (a) the "cross-TU Entity
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layout divergence" (disproven separately — an `offsetof` probe showed `Entity` is IDENTICAL in both TUs:
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`sizeof=444`, `entityID@380 (0x17C)`, `ownerID@388`, `simulationFlags@32`; distinct from the REAL P5
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raw-offset stomps at `this+0x2d4..0x2f0` in `docs/HARD_PROBLEMS.md`), and (b) the "localID drops by hostID
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on the wire" claim. Both are FALSE. The id is correct end-to-end (`3:22` = B's master); nothing on the wire
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is corrupted. Lesson: when a message probe seems to see a wrong id, first confirm the numeric messageID.
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Retained gated instrument: `[mp-force]` (BT_MP_FORCE_DMG + BT_MP_LOG) — the 2-node cross-pod reproducer,
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off in solo. `[mp-hdlr]` (BT_MP_NET, mech.cpp:554) logs each applied cross-pod hit. 2-node launch recipe +
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`scratchpad/mp_test.sh`: A `-egg MP.EGG -net 1501`, B `-net 1601`, then `python tools/btconsole.py MP.EGG
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127.0.0.1:1501 127.0.0.1:1601` (MP.EGG `[pilots]` = game ports 1502/1602).
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## Interactive -net aim + drive (task #48, 2026-07-09) [T2]
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Re-measured on a 2-node one-box run. **The prior "aim ray dead / drive dead in -net" claim was STALE — both
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work:** A's aim ray is live (`noRay=0`) and A drives (`BT_AUTODRIVE`/`BT_GOTO` move it).
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**FIXED — torso-pitch aim ray (gyro-stabilized boresight).** The aim/pick ray was the active RENDER EYE's
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view direction, which (a) inherits the mech BODY pitch — on a slope the body tilts ~8° to conform to terrain
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and the boresight pointed that far DOWN, hitting terrain ~50-100 m short of the enemy (`groundPicks`, never
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`mechPicks`); and (b) in CHASE view (the DEFAULT) is the elevated behind-the-shoulder camera, so the ray
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started over the mech's shoulder. Fix (L4VIDRND `DPLEyeRenderable::Execute`, the `BTSetAimCamera` publish):
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LEVEL the boresight (drop the view-dir pitch, rebuild an upright basis with world +Y) AND anchor its ORIGIN
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at the mech's torso (`myEntity->localToWorld` translation + ~5) instead of the render eye. The guns now fire
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along the mech's horizontal heading from the torso, independent of view mode and terrain tilt. The reticle X
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still carries the torso twist (`BTTwistToReticleX`); reticle Y any elevation. VERIFIED end-to-end: solo,
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enemy 120 m ahead, **both chase AND cockpit** view → `[target] MECH under boresight ... mechPicks=59
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groundPicks=0` → beam → `*** DESTROYED`. Also proved `PickRayHit` resolves a REPLICANT when aimed at it
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(`hit=1` at 757 m in a 2-node run); the replicant `localToWorld` is correct (DeadReckon + `localToWorld=
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localOrigin`, mech4.cpp:1191). [T2]
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**FIXED — drive-to-range (the automated cross-pod kill now runs end-to-end).** The `BT_GOTO` beeline had
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three separate faults: (1) it was gated behind `if(gBTDrive.forced)` (mech4.cpp), and `forced` was set ONLY
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by `BT_AUTODRIVE` — so `BT_GOTO` alone never drove (chicken-and-egg: the block that would drive was gated on
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the drive being on). Fix: `BT_GOTO` now enables forced mode itself + supplies its own forward throttle (a
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"beeline" must drive, not just steer), cutting throttle inside a stop radius (weapon range for `enemy`, so it
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holds and shoots instead of ramming). (2) The steering used the `gDriveHeading` SCALAR MIRROR (seeded to 0),
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but MP pilots spawn facing a non-zero heading, so the beeline steered the WRONG way. Fix: compute the heading
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error from the mech's ACTUAL forward (`localToWorld`'s -Z axis), signed angle to the target. (3) The goto turn
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was routed through `controlsMapper->turnDemand`, which read 0 in -net — the heading froze and A drove straight
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past B. Fix: apply the goto turn to the orientation integration DIRECTLY (`if(gBTGotoActive) turn=gBTGotoTurn`),
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after the mapper read. **CAUSE FOUND LATER (task #51): turnDemand zeroed because `controlMode` was pointer
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garbage — the `pilotArray[1]` shrunk-span overrun (see [[reconstruction-gotchas]] §5), MP-only because solo's
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overrun wrote 0==BasicMode. Fixed at the root (10-slot array); the direct goto-turn stays (harmless, and it
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skips the 1-frame mapper latency). KEYBOARD turning in MP was restored by the root fix.**
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VERIFIED 2-node: A `BT_GOTO="enemy"` alone (no autodrive) drives `dist 1673→231 m`, holds at range, `mechPicks=59`,
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autofire → **B hdlr=192, DESTROYED** — a fully automated human-style cross-pod kill via the real beam path
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(not the FORCE_DMG hook). Solo un-regressed (plain autodrive + goto both work). `scratchpad/mp_kill_test.sh`;
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`BT_GOTO_LOG` traces the beeline.
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## Replicant gait animation (task #50, 2026-07-09) — DONE [T2]
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A peer's replicant used to slide as a frozen statue (DeadReckon moved it; nothing animated it). Now the
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replicant block (mech4.cpp, after `DeadReckon`) derives a SIGNED speed demand from the replicated
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velocity — the master publishes `worldLinearVelocity` in every update record (`Mover::WriteUpdateRecord`
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MOVER.cpp:759), the replicant stores it in `updateVelocity.linearMotion` (:712); sign = the forward dot
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against the mech's -Z facing — writes it to `controlsMapper->speedDemand` (the LEG channel's live source)
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and advances the LEG state machine for its JOINT writes only. Travel stays DeadReckon (the returned
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distance is discarded) so position always follows the master; the clip cadence matches the replicated
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speed. ⚠ REPLICANT GAIT-SCALAR PRIMING (same class as the master's per-frame primes, which live in the
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PLAYER-only drive block): `globalTimeScale`/`idleStrideScale` read 0 on a replicant (clip frozen at
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advance-time dt*0, legState engaged but legCycle stuck 0), and `reverseSpeedMax2`@0x7a0 (the run-cycle
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rise-clamp; LoadLocomotionClips does NOT set it) read debug-heap garbage → legCycleSpeed clamped to
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-4.3e8 entering run state 13. Both primed in the replicant block; `legCycleSpeed` itself sane-banded once.
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VERIFIED 2-node: the observer's replicant runs the full lifecycle — stand→walk(5,7)→run(10,12) with
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legCycle 7.5→34 tracking the master's speed, wind-down (8) and back to Standing(0) when the master stops.
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Solo un-regressed. `BT_REPL_LOG` traces pos/vel/legState/legCycle; recipe `scratchpad/mp_gait_test.sh`.
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NOTE: the update-record velocity is currently the master's ACTUAL travel velocity (worldLinearVelocity
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from the leg channel); the binary publishes the BODY channel's smoothed projection (projectedVelocity,
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disasm +0x2a0). Swapping the source is a fidelity refinement DEFERRED — it risks a verified working feed
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for a smoothing nuance. [T3 on that nuance]
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## Remaining (P6 phase 4 / Phase 7)
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The pod-LAN config (real IPs, bare-IP pilot entries); update-record velocity sourced from the body-channel
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projection (above). See [[open-questions]]. [T3]
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## MP-front scout (task #45, 2026-07-09) — the P6 chain SURVIVES the combat/HUD rework [T2]
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Re-ran the one-box smoke test on the current build (world-pick targeting, weapon groups, death
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transition, HUD all landed since P6): console egg → mesh → RunningMission on BOTH instances, 174+
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×144-byte update records EACH side (msgID=6), 2 mech trees per instance, 0 crashes over ~6 min.
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**Gap map to a first playable LAN fight** (in wiring order):
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1. **Enemy selection**: the world-pick tests only `gEnemyMech` (the solo dummy, btplayer.cpp:791).
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MP: the pick must test every OTHER mech (the peer replicants) — generalize to a candidate walk
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(mech entities != viewpoint). Small.
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2. **Cross-pod damage**: dispatch TakeDamage at the REPLICANT → verify the engine reroute carries
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it to the owning master (the KB claims Dispatch reroutes; not yet exercised with our STEP-6
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handler). The master takes real zone damage + runs its own death transition (task #42 placed the
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death dispatch victim-side — MP-correct by construction).
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3. **Victim visuals on the shooter's screen**: the wreck swap gates on zone/graphic state the
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REPLICANT copy may never see (zone damage may not replicate — only pose updates confirmed).
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Check DamageZone/subsystem state in the update stream; else replicate the death as an event.
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4. ✅ **Cross-pod beam visuals — DONE (task #51, 2026-07-09).** The keepalive theory needed one
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correction: `FUN_0041c350` = (a) queue the LOCAL deferred beam-effect callback (@0x4bac0c) on the
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app+0x34 manager (our per-weapon render walk plays that role) AND (b) set the subsystem DIRTY bit —
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which maps to the 2007 engine's `updateModel`/`ForceUpdate()`. The REPLICATION rides **subsystem
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update records inside the mech's update message**: the roster walk passes the entity's stream to
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every subsystem's `PerformAndWatch`; `Emitter::WriteUpdateRecord` (@004ba65c, corrected: record
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LENGTH not recordID; rec+0x30 = the TARGET's **EntityID** not a colour) serializes
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firingActive/beamEndpoint/beamFlag/targetID; the engine's `Entity::UpdateMessageHandler` routes
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records by `subsystemID` to `Emitter::ReadUpdateRecord` (@004ba568 — was MIStranscribed as
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TakeDamage; the whole weapon-family slot map was swapped: slot 6=Read, 7=Write, 9=TakeDamage — see
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mechweap.hpp). `ServiceDischarge`/`ContinueDischarge` call `ForceUpdate()` per keepalive tick +
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once at beam end. The render walk was extracted to `Mech::DrawWeaponBeams` (per-mech port cache)
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and runs for REPLICANTS. ⚠ two silent-failure traps fixed: the overrides originally used the
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class's own shadowing `UpdateRecord` typedef as the param type → never overrode the engine virtual
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(base ran, nothing serialized); and `recordLength` must be each level's sizeof or the stream
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framing misparses. VERIFIED 2-node: A fires 57 volleys → 225 records → B applies 225 → draws 414
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replicant beams (PPC blue / laser red from A's replicant's gun ports). Solo un-regressed.
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REMAINING (deferred): the MECH-level writer @0x4a0c2c (recovered + preserved:
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`reference/decomp/mech_writeupdate_004a0c2c.disasm.txt`; 9 record types decoded — 0/1/4 pose
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variants, 2 alarm, 3 leg-state+heat with body-channel write-through re-sync, 5 knockdown
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(SetBodyAnimation(0x20) write-through), 6 death, 7 impact, 8 movementMode) — transcribing it
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would replicate remote KNOCKDOWN/death/heat states; beams did not need it.
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5. **2-window driving**: input gates on window focus (alternate windows; `BT_KEY_NOFOCUS` for
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harness). DEATHS scoring should light via the existing BTPostKillScore MP branch. Respawn =
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the P5 teardown debt (deferred until needed).
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## Key Relationships
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- Base: [[wintesla-port]] (L4NET). Depends on: [[locomotion]] (update writer), [[combat-damage]]
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(entity lifecycle). Detail: `docs/HARD_PROBLEMS.md` (P6).
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