BT412: fork from BT411 -- Steam + internet-multiplayer line

Identity pass (README/CLAUDE.md/CMake project bt412), the steamification roadmap (docs/BT412-ROADMAP.md), and the living context topic (context/steamification.md). Forked at BT411 4e72f0c; origin is VWE/BT412.git only -- this repo never touches the BT411 remote. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-14 07:24:05 -05:00
parent 4e72f0c4f4
commit d8dd512843
5 changed files with 292 additions and 19 deletions
@@ -5,14 +5,18 @@
 > detail is preserved verbatim in **`docs/PROGRESS_LOG.md`** (the old monolithic CLAUDE.md) — the
 > ultimate fallback if a topic digest is thin. Migration history: `phases/phase-01-context-restructure.md`.

-**Project:** Port VWE's 1995 arcade **BattleTech** (BT) pod game (MUNGA engine, Tesla platform
-4.10) to modern Windows + the pod hardware, by reconstructing the missing BT game logic from the
-`BTL4OPT.EXE` binary on top of the working WinTesla engine.
+**Project:** **BT412 — the Steamification of the BattleTech pod port.** The upstream work
+(BT411) ports VWE's 1995 arcade **BattleTech** (BT) pod game (MUNGA engine, Tesla platform 4.10)
+to modern Windows by reconstructing the missing BT game logic from the `BTL4OPT.EXE` binary on
+top of the working WinTesla engine. This repo carries that forward to a consumer Steam title:
+virtual cockpit controls (no pod hardware), single-window cockpit, in-game session front end
+replacing the operator console, Steam internet multiplayer, distributable packaging.
 **Repo of record:** the top-level `CMakeLists.txt` + `README.md` build `btl4.exe`. Layout:
-`engine/ game/ content/ docs/ reference/ tools/ context/`.
-**Current front:** `btl4.exe` runs a full single-player loop; the gauge system is complete; the
-active work is reconstructing each subsystem's authentic behavior from the binary. Details +
-what's-next: `context/project-overview.md`, `context/open-questions.md`, recent git log.
+`engine/ game/ content/ docs/ reference/ tools/ context/`. Remote: `origin` =
+`VWE/BT412.git` ONLY — this repo must never touch the BT411 remote (no cross-pull remote).
+**Current front:** the steamification — plan and phase order in `docs/BT412-ROADMAP.md`, running
+status in `context/steamification.md`. Subsystem-fidelity reconstruction continues alongside.
+Details + what's-next: `context/project-overview.md`, `context/open-questions.md`, recent git log.

 ---

@@ -57,6 +61,7 @@ precise than anything you can infer.
 | User asks about... | Read this file |
 |---|---|
 | What the project is, engine, platform, goal | `context/project-overview.md` |
+| The Steamification (BT412): plan, phases, PadRIO, Steam net, front end | `context/steamification.md` + `docs/BT412-ROADMAP.md` |
 | Missing BT source, decompilation strategy | `context/source-completeness.md` |
 | The WinTesla Windows port (renderer/audio/HAL) | `context/wintesla-port.md` |
 | Build / run / debug / repo layout / env gates | `context/build-and-run.md` + `context/decomp-reference.md` §6 |
@@ -1,10 +1,11 @@
 cmake_minimum_required(VERSION 3.20)
-project(bt411 CXX)
+project(bt412 CXX)
 set(CMAKE_CXX_STANDARD 14)

-# BattleTech 4.11 -- Virtual World Entertainment pod BattleTech (Tesla rel 4.10)
-# reconstructed on the shared RP411 Windows engine.  Build 32-bit (Win32) with
-# the VS2019 BuildTools instance -- see README.md for the exact configure line.
+# BattleTech 4.12 -- the Steamification of the BT411 pod port (Virtual World
+# Entertainment pod BattleTech, Tesla rel 4.10, reconstructed on the shared
+# RP411 Windows engine).  Build 32-bit (Win32) -- see README.md for the exact
+# configure line, docs/BT412-ROADMAP.md for the plan.
 # Run from the content dir:  cd content && ../build/Debug/btl4.exe -egg DEV.EGG

 # --- external dependency: legacy DirectX SDK (June 2010); override with -DDXSDK=... ---
@@ -1,13 +1,19 @@
-# BattleTech 4.11 (bt411)
+# BattleTech 4.12 (bt412) — the Steamification

-A standalone Windows port of **Virtual World Entertainment's arcade *BattleTech*** (Tesla
-platform, release 4.10, ~1995–96), reconstructed on the shared **RP411 Windows engine**. The
-game boots, renders, and runs a single-player **drive → animate → target → fire → damage →
-destroy** loop across all 8 maps, with two-instance multiplayer entity replication working.
+**BattleTech** is VWE's arcade mech-combat game (Tesla platform, release 4.10, ~1995–96),
+originally played from inside Virtual World cockpit pods. This repo is the consumer line of
+that reconstruction:

-This repo is a clean, self-contained extraction of the BattleTech-specific work from the larger
-reverse-engineering workspace — engine + game + content + build, with nothing from Red Planet or
-the raw archive dumps. It builds and runs out of the box.
+| Generation | What it was |
+|------------|-------------|
+| **BattleTech 4.10** | The original pod game — DOS-era MUNGA engine, serial RIO cockpit I/O, 7-monitor cockpit, operator console |
+| **BattleTech 4.11** | The **Win32 port** — the BT game logic reconstructed from `BTL4OPT.EXE` on the shared RP411 Windows engine; DirectX 9, full single-player combat loop, two-instance LAN multiplayer |
+| **BattleTech 4.12** | **This repo: the Steamification of 4.11** — the same engine, missions, and wire protocol, made distributable on Steam and playable over the internet with no pod hardware |
+
+The plan and workstreams live in [docs/BT412-ROADMAP.md](docs/BT412-ROADMAP.md). The sister
+project **RP412** (Red Planet's steamification, shipped end-to-end: lobby → Steam-sockets mesh →
+marshaled race → results on every machine) is the proven recipe this repo follows — each pod-era
+dependency replaced by a consumer equivalent behind the engine's existing seams.

 > **License:** the game content (`content/`) and the original binary are proprietary to Virtual
 > World / the pod owner. This repository is **private**; do not redistribute.
@@ -0,0 +1,83 @@
+---
+id: steamification
+title: "BT412 Steamification — status, seams, and merge notes"
+status: living
+source_sections: "docs/BT412-ROADMAP.md; RP412 repo (C:\\vwe\\RP412) git history + docs"
+related_topics: [pod-hardware, multiplayer, gauges-hud, build-and-run, wintesla-port]
+key_terms: [egg, RIO, console]
+open_questions:
+  - "BT cockpit button-bank geometry source (no vRIO CockpitLayout exists for BT): l4gauge.cfg / pod photos / Nick"
+  - "Does BT's rebuilt L4D3D still have RP's NULL-texture AddRef crash pattern?"
+  - "Does L4CONTROLS=PAD set primaryControlType=PrimaryRIO so MechRIOMapper engages unchanged?"
+---
+# BT412 Steamification — status, seams, and merge notes
+
+BT412 = BT411 made distributable on Steam and playable over the internet with no pod
+hardware, following the recipe RP412 proved end-to-end (RP411 → RP412). The full plan
+and phase order: `docs/BT412-ROADMAP.md`. RP412 (`C:\vwe\RP412`) is the reference
+implementation — its git history from commit `467934c` onward is the steamification,
+grouped roughly: toolchain → PadRIO input → MFD-split cockpit → front end/LocalConsole
+→ NetTransport/Steam sockets → lobby → bindings/KeyLight → packaging.
+
+**Repo rule [T0]:** `origin` = `VWE/BT412.git` only. This repo must never touch the
+BT411 remote (no cross-pull remote — deliberate difference from RP412's `rp411`
+pattern). Forked at BT411 `4e72f0c` (2026-07-14).
+
+## Status ledger
+
+- **Phase 0 bootstrap — DONE 2026-07-14.** Tree copied (working tree + full history,
+  `build/` excluded), origin re-pointed, fast-forwarded to `4e72f0c`, dev-state
+  `run/run.cmd` working-tree edit discarded (committed version is the documented solo
+  launcher), identity pass (README/CLAUDE.md/CMake `project(bt412)`), this topic +
+  roadmap authored.
+- Phase 1 (VS2022 v143): not started.
+- Phases 2–7: not started — see the roadmap.
+
+## The seams (what plugs in where) [T0 unless noted]
+
+- **Input**: `LBE4ControlsManager` PUSH model; `L4CTRL.cpp` parses `L4CONTROLS` tokens;
+  RP412 adds token `PAD` → `new PadRIO()` (a `RIOBase` implementation from
+  XInput+keyboard), and the stock RIO mapper runs against it unchanged. BT's mapper
+  selection: `btl4app.cpp MakeViewpointEntity` switch on
+  `controls->primaryControlType` (+0xc98) → `MechRIOMapper` for PrimaryRIO(4).
+- **Plasma**: BT's plasma is identical hardware to RP's (128×32, `L4PLASMA.h`);
+  RP412's `PlasmaScreen` renders the same `Video8BitBuffered` surface into a desktop
+  window, selected in `L4GREND.cpp` on `L4PLASMA=SCREEN`.
+- **Displays**: BT pod = main 800×600 3D view + 640×480 radar + five mono MFDs on one
+  spanned 1280×480 surface (+ plasma). All cockpit surfaces are bit-plane masks over
+  one shared `SVGA16` pixelBuffer (see [[gauges-hud]], [[pod-hardware]]). RP412's
+  `MFDSplitView` (`L4MFDVIEW.*` + `L4VB16.cpp` split mode, `L4MFDSPLIT=1`) composes
+  child panes on a fixed 1920×1080 canvas; 3D presents into the viewscreen pane via
+  `Present(hDestWindowOverride)`.
+- **Networking**: arcade stack unchanged (see [[multiplayer]]); RP412 moved the wire
+  behind `NetTransport` (`L4NETTRANSPORT.*`), default `WinsockNetTransport`, Steam
+  implementation `L4STEAMTRANSPORT.*` (`ISteamNetworkingSockets`, FakeIP + SDR,
+  degrade-to-TCP on any failure). Addresses stay SOCKADDR_IN-shaped so the egg
+  `[pilots] ip[:port]` roster works over both wires.
+- **Session**: console protocol (egg msgID 3, 1040-byte chunks + ACK; RunMission
+  msgID 5 ×2; console must stay connected) — `tools/btconsole.py` is the working
+  feeder and the spec for the in-process LocalConsole marshal (Phase 5).
+
+## Known merge risks (from the 3-way BT411 / RP411-baseline / RP412 comparison)
+
+- **`L4VB16.cpp` — HIGH.** RP412 rebuilt ~3846–4046 (splitViews/canvas/present); BT
+  rebuilt the same window-management region for dev-gauge docking (`BT_DEV_GAUGES`,
+  `BT_DEV_GAUGES_WINDOW`, `BT_DEV_GAUGES_DOCK`, `BT_GAUGE_SCALE`, `BT_GAUGE_SEC_ROT`,
+  `BT_ALL` — 15 sites). Hand-merge; write the 3-way diff notes HERE before editing.
+- **`L4NET.CPP` — MEDIUM.** RP412 rerouted all ~22–26 Winsock call sites through
+  `NetTransport_Get()`; BT's 5 `BT_NET_TRACE` diagnostic blocks sit exactly on those
+  send/receive sites and must be re-sited onto the seam calls.
+- **`L4RIO.*`, `L4CTRL.cpp`, `L4GREND.cpp` — LOW.** BT never customized these
+  (verified: zero BT_ hits); take RP412's versions after the 3-way check.
+- **CMake**: engine sources are explicit per-file lines (no globs) — every ported
+  `.cpp` needs its own `add_library` line or it silently doesn't compile. New deps:
+  `xinput9_1_0.lib` (PadRIO), C++/WinRT (KeyLight, per-file C++17), Steamworks SDK +
+  `steam_api.lib` behind `option(BT412_STEAM)`.
+- **No `/Zp1` in BT's build** (RP's engine builds `/Zp1`): RP412's packing-mismatch
+  workarounds (`WINDOWS_IGNORE_PACKING_MISMATCH`, KeyLight default-packing carve-out,
+  `pack(push,8)` around Steam headers) are no-ops here — keep them for verbatim-ness,
+  but eyeball any copied code for /Zp1-layout assumptions.
+
+## Key Relationships
+- Uses: [[pod-hardware]] · [[multiplayer]] · [[gauges-hud]] · [[build-and-run]]
+- Feeds: [[open-questions]] (steamification investigate items)
@@ -0,0 +1,178 @@
+# BT 4.12 Roadmap — Steam + Internet Multiplayer
+
+Working plan for turning the 4.11 pod port into a consumer Steam title, following the
+recipe proven end-to-end by **RP412** (Red Planet 4.11 → 4.12; see
+`C:\vwe\RP412\docs\RP412-ROADMAP.md` and its git history — the reference implementation
+for every workstream here). Status: plan authored 2026-07-14. Items marked
+**[investigate]** need archaeology before they become concrete tasks.
+
+## Where 4.11 stands
+
+- **Game**: `btl4.exe`, 32-bit Win32, DirectX 9, CMake + VS2019 BuildTools (v142),
+  DXSDK June 2010, `/FORCE:MULTIPLE`. Full single-player combat loop
+  (drive → animate → target → fire → damage → destroy → respawn) on all 8 maps.
+- **Engine**: the same WinTesla MUNGA/MUNGA_L4 engine as Red Planet — the MUNGA core is
+  file-identical to RP's; BT's L4 layer adds bgfload/image + BT render work
+  (L4D3D/L4VIDEO) and dev-gauge docking in L4VB16.
+- **Networking**: same arcade stack — `MUNGA/NETWORK|HOSTMGR|INTEREST`, WinSock2 TCP in
+  `MUNGA_L4/L4NET.CPP`. Two-instance loopback MP verified including cross-pod combat,
+  kills, respawn, gait, and weapon visuals. Console feeder: `tools/btconsole.py`
+  (egg msgID 3 in 1040-byte chunks, RunMission msgID 5 ×2, must stay connected).
+- **Input/output**: pod hardware is a serial **RIO** board (stick X/Y, throttle, pedals,
+  fire/config buttons 0x40/0x45/0x46/0x47 + MFD aux buttons) — `L4RIO`/`L4SERIAL`. Dev
+  box uses keyboard debug controls (WASD etc.). Displays: **7 monitors** (main 800×600
+  3D view, radar 640×480, five mono MFDs as one spanned 1280×480 surface) + the
+  **128×32 plasma** (identical hardware to RP's; `L4PLASMA`). `BT_DEV_GAUGES` docks the
+  gauge strip into the main window (dev mode).
+- **Session control**: missions are **egg** files (NotationFile); the operator console
+  configures and launches over TCP 1501. No in-game menu; no mission-end flow (mission
+  review msgID 0x18 is a stub, `scoreAward=0`); live kill/death tally exists on the
+  Comm MFD `pilotList`.
+
+## Defaults (decided at planning, change only deliberately)
+
+- Gates mirror RP412 with a BT412 prefix: `BT412_STEAM`, `BT412KEYLIGHT`, env
+  `BT412STEAM=1`. Exe stays `btl4.exe`; CMake project is `bt412`.
+- AppID: Spacewar **480** via hand-created `steam_appid.txt` (gitignored, never packed)
+  until a real AppID exists.
+- Mech catalog: base 8 (`avatar bhk1 loki madcat owens sunder thor vulture`) + variants
+  (`ava1 lok1 lok2 mad1 mad2 own1 snd1 thr1 vul1 blkhawk`); trim any that fail to load.
+- Results v1: read the live Comm-MFD `pilotList` tally (kills + observed deaths) at
+  stop; EndMission wire scores when remote-pod marshaling needs them.
+- `L4VB16.cpp` end-state: `MFDSplitView` is the successor to the dev-gauge dock; keep
+  `BT_DEV_GAUGES` gated until parity, then retire.
+- **This repo never touches the BT411 remote.** `origin` = `VWE/BT412.git` only.
+
+## Phase 1 — Toolchain: VS2022 (v143)
+
+RP412's step 1: unblocks everything, no design risk.
+
+- Configure `-G "Visual Studio 17 2022" -A Win32` (drop the 2019
+  `CMAKE_GENERATOR_INSTANCE`). **Stay Win32** — DXSDK June 2010 x86 libs are the hard
+  constraint. BT's CMake has no `/Zp1`, so RP's packing-mismatch defines don't apply.
+- Apply RP412 BUILD.md §3 source fixes as v143 errors demand: `MUNGA/TIME.h` Time
+  copy-ctor; `MUNGA/NETWORK.h` inline `operator==`; `L4DINPUT.cpp` DIEnum callback
+  renames; `CAMMGR.cpp` `std::ios::in`; `legacy_stdio_definitions.lib` for dxerr.
+- [investigate] RP412's `L4D3D.cpp` NULL-texture AddRef guard — BT's L4D3D is heavily
+  rebuilt; port the guard if the crash pattern survives.
+- **Verify**: v143 build boots DEV.EGG; two-instance loopback + btconsole.py — drive,
+  fire, cross-pod kill, respawn.
+
+## Phase 2 — Input layer: RIOBase / PadRIO (Workstream A.1)
+
+Rule for every touched engine file: 3-way check (BT copy vs RP411 baseline vs RP412);
+identical-to-baseline → take RP412's file verbatim, diverged → hand-apply the diff.
+
+- Port `L4RIO.h/.cpp` (RIOBase split), new `L4PADRIO.*`, `L4PADBINDINGS.*`; the
+  `L4CTRL.cpp` hook (`new PadRIO()` for token `PAD`). BT never customized these —
+  expected clean.
+- CMake: explicit source lines (no globs); link `xinput9_1_0.lib`.
+- Confirm `L4CONTROLS=PAD` yields `primaryControlType=PrimaryRIO` so the stock
+  `MechRIOMapper` engages unchanged (`btl4app.cpp MakeViewpointEntity`) — RP precedent:
+  stock VTVRIOMapper ran against PadRIO unmodified.
+- Author the default BT `bindings.txt` (vRIO grammar): stick/throttle/pedal axes, fire
+  buttons, MFD aux banks.
+- Fix desktop-unreachable controls: secondary-MFD view cycling (mapper cases
+  0x13d/0x13e are dead DOS F3/F4 codes). Weapon regrouping comes alive via the RIO
+  path for free.
+- **Verify**: full mech drive+fight from pad+keyboard, no COM ports; pad hot-plug;
+  `L4CONTROLS=RIO` pod regression still initializes.
+
+## Phase 3 — Cockpit on the desktop (Workstream A.2)
+
+- **3a PlasmaScreen** (low risk, land first): `L4PLASMASCREEN.*` verbatim + the
+  `L4GREND.cpp` selector diff. `L4PLASMA=SCREEN`.
+- **3b Single-window MFD split** (`L4MFDSPLIT=1`) — **the HIGH-risk hand-merge**:
+  RP412 rebuilt `L4VB16.cpp` ~3846–4046 (splitViews, fixed 1920×1080 canvas,
+  3D Present into the viewscreen pane via `hDestWindowOverride`); BT rebuilt the same
+  region for dev-gauge docking (`BT_DEV_GAUGES*`, `BT_GAUGE_*`, `BT_ALL` — 15 sites).
+  Write 3-way diff notes into `context/steamification.md` **before** editing.
+  `L4MFDVIEW.*` copied as skeleton; replace RP's pod tables with BT's display set
+  (viewscreen, radar, five mono MFDs sliced from the 1280×480 span, plasma glass).
+- **[investigate]** BT cockpit button-bank geometry: no vRIO `CockpitLayout` exists for
+  the BT pod. Sources: `content/GAUGE/l4gauge.cfg`, pod photos, ask Nick. Land
+  panes-without-buttons first; clicks inject `PadRIO::SetScreenButton`, lamps light
+  from `GetLampState` once geometry lands.
+- **Verify**: one cockpit window, 3D presents into its pane (smoke BT's rebuilt L4D3D
+  present path EARLY), live MFDs/radar/plasma; pod multi-surface path (`L4GAUGE`)
+  unbroken.
+
+## Phase 4 — NetTransport seam + Steam transport (Workstream C.1)
+
+- `L4NETTRANSPORT.*` verbatim (abstract seam + `WinsockNetTransport` default;
+  SOCKADDR_IN-shaped addresses keep egg `[pilots] ip[:port]` working in both worlds).
+- `L4NET.CPP`: apply RP412's refactor (~22–26 Winsock sites → `NetTransport_Get()`);
+  **re-site the 5 `BT_NET_TRACE` blocks** onto the seam calls.
+- `L4STEAMTRANSPORT.*` near-verbatim, gate `BT412_STEAM`; vendor
+  `extern/steamworks_sdk_164/` (copy from RP412).
+- CMake: seam always compiled; `option(BT412_STEAM)` gates the transport TU + define +
+  SDK include + `steam_api.lib` + post-build dll copy.
+- **Verify**: (1) loopback + btconsole.py full MP parity through the seam (TCP);
+  (2) Steam smoke — transport installs, FakeIP allocated, graceful TCP degrade when
+  Steam is absent; (3) real Steam-sockets session (may defer to Phase 6).
+
+## Phase 5 — Front end + LocalConsole marshal (Workstream B — bulk of new code)
+
+- **5a `game/reconstructed/btl4fe.cpp`** (skeleton: RP412 `RP_L4/RPL4FE.cpp`): no
+  `-egg`/`-net` → setup menu. Catalog: 8 maps
+  (`cavern grass rav polar3 polar4 arena1 arena2 dbase`), mechs per defaults,
+  scenario=freeforall, time/weather/temperature/length, pilot name.
+  `BTMission::ToEggString` against the verified egg format (`content/MP.EGG`,
+  `DEV.EGG`) incl. GDI-rendered 128×32 `[ordinals]`/name plasma bitmaps → the standard
+  egg-load path.
+- **5b `game/reconstructed/btl4console.cpp`** (skeleton: `RPL4CONSOLE.cpp`): in-process
+  console on its own thread over NetTransport — egg chunks + ACK, RunMission ×2
+  (mirror btconsole.py), stays connected (fixes the console-loss listener bug for
+  solo), owns the mission clock, StopMission at `length=` expiry, launcher-role loop,
+  `InstallNetworkRace` marshal for remote pods.
+- **5c Score intake — genuinely new for BT** (no mission-end flow exists): a
+  `gConsoleScoreSink` equivalent through `BTPlayer`; v1 results screen = kills/deaths
+  per pilot from the Comm-MFD `pilotList` tally at stop.
+- **5d `game/btl4main.cpp` WinMain wiring** (skeleton: RP412 `RPL4.CPP` diff):
+  front-end-mode detection, single-binary `for(;;)` loop (results → menu → launch),
+  host/member branch, self-documenting `environ.ini` parsing, minidump crash filter,
+  `SC_KEYMENU` swallow, `BT412STEAM` env → `SteamNetTransport_Install()`.
+- **Verify**: no-args boot → menu → LAUNCH → mission → stop at set length → results →
+  fresh menu; `-egg DEV.EGG` stays unmarshaled (dev shortcut); btconsole.py external
+  feed still works; marshaled 2-instance loopback collects both score lines.
+
+## Phase 6 — Steam lobby (Workstream C.2)
+
+- **`game/reconstructed/btl4lobby.cpp`** (skeleton: `RPL4LOBBY.cpp` — mechanics
+  generic): lobby owner = console; member data = FakeIP + fake console/game ports +
+  persona + loadout (**mech**/color/badge); nonced launch roster → `RegisterPeer` all →
+  owner hosts via egg+marshal, members join as network pods; Push/PullRaceResults
+  distribute the score sheet. FE gains HOST/JOIN screens.
+- Author `docs/STEAM-3-MACHINE-TEST.md` for BT (adapt RP412's; keep its gotchas:
+  disable Steam Input on 480, one Steam account per machine, abort key).
+- **Verify**: 3-machine Steam test — lobby → mesh → marshaled timed mission →
+  kills/deaths → stop → results everywhere → rematch. Known MP fidelity gaps (peer
+  warp spheres, missile clusters, PNAME/PLACE billboards) do not block.
+
+## Phase 7 — Polish, packaging, release
+
+- KeyLight RGB mirror: `L4KEYLIGHT.*` verbatim (C++/WinRT TU — per-file C++17 props),
+  gate `BT412KEYLIGHT`.
+- `pack-dist.ps1` adapted: `btl4.exe`+pdb, `BTL4.RES`, `BTDPL.INI`,
+  `VIDEO/ GAUGE/ AUDIO/`, eggs, `steam_api.dll`, OpenAL runtime, generated commented
+  `environ.ini`, `start-windowed.bat`, README.txt, refuse-while-running.
+- `tools/two-pod-test.ps1` adapted (feeder = btconsole.py). Version banner `4.12.x`;
+  tag the release on gitea.
+- **Verify**: dist zip runs on a clean machine (no DXSDK); solo loop; packaged
+  2-machine Steam session.
+
+## Copy matrix (from RP412)
+
+| Treatment | Files |
+|-----------|-------|
+| **Verbatim** (after 3-way check) | `L4PADRIO.*`, `L4PADBINDINGS.*`, `L4PLASMASCREEN.*`, `L4NETTRANSPORT.*`, `L4STEAMTRANSPORT.*` (gate rename), `L4KEYLIGHT.*` (gate rename), `extern/steamworks_sdk_164/` |
+| **Diff-apply / hand-merge** | `L4RIO.*`, `L4CTRL.cpp`, `L4GREND.cpp` (expected clean); `L4NET.CPP` (medium — BT_NET_TRACE); `L4VB16.cpp` (**high** — dev-gauge collision); `L4VIDEO.*`; v143 source fixes |
+| **Adapt** (RP skeleton, BT tables/fields) | `L4MFDVIEW.*`, `btl4lobby`, `pack-dist.ps1`, `two-pod-test.ps1`, `environ.ini` template, STEAM-3-MACHINE-TEST doc |
+| **New** | `btl4fe`, `btl4console`, score sink + results screen, BT `bindings.txt`, CMake Steam gating, `context/steamification.md` |
+
+## Standing regressions (after every engine-file merge)
+
+1. Solo: `run\run.cmd` boots DEV.EGG; drive → fire → kill → respawn works.
+2. Loopback MP via btconsole.py keeps entity/combat replication.
+3. Pod paths (`L4CONTROLS=RIO`, `L4GAUGE`, `L4PLASMA=com2`) still compile and
+   initialize.