Game Remake

Game Remake

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Faithful C++ reimplementation of Might & Magic II (Amiga), driven by the 68k disassembly and decoded .dat / asset formats in EXTRACTED/.

Design principle

• 100% ASM/Amiga fidelity — match original 68k behaviour exactly; no invented UX. See Game remake (game/) in CLAUDE.md.
• AGA port (planned) — 6 bitplanes, extension palette, multi-monster combat art, future UI, and additive dungeons/content: EXTRACTED/docs/41-aga-port-plan.md.

Targets

Platform	Backend	C/C++ runtime
Windows, Linux, macOS	SDL2	Host libc + libstdc++
Amiga (68000+)	ACE (AmigaPorts/ACE)	mini-std + custom new/delete/operator[] — no libstdc++

Desktop builds use SDL2 directly (not ACE’s experimental SDL shim). Amiga builds link ACE for blitter/copper/input/audio and route all dynamic allocation through mm2::runtime (memAlloc / memFree).

Layout

game/
  CMakeLists.txt
  include/mm2/          Shared headers (platform-neutral game API)
  src/
    main.cpp            Entry (desktop) or thin wrapper (Amiga + ACE generic main)
    Game.cpp            High-level setup / tick / draw
    TitleScreen.cpp     Title attract/menu (320×200), logo, peekers
    ui/                 Character UI backends (AmigaClassic / Stub)
    gfx/                320×200 compositor + Mm2Font8x8.inc
    platform/sdl/       SDL2 window, input, file I/O
    platform/amiga/     ACE viewport, chip/fast mem, OS file hooks
    runtime/            Allocators, freestanding buffers
EXTRACTED/decomp/       Pure-C codecs lifted from RE (shared with editor tools)

Architecture

flowchart TB
  subgraph host [Host layer]
    SDL[SDL2 PC/Linux]
    ACE[ACE Amiga]
  end
  subgraph plat [mm2::platform]
    IO[File I/O]
    IN[Input]
    VID[Present / blit]
    CLK[Timer]
  end
  subgraph core [Game core — portable C++]
    GS[GameState A4 workspace]
    MAP[map.dat + 3D view]
    EVT[event VM 0x172CA]
    CBT[combat 0x12A22]
    SVC[town services]
  end
  subgraph data [Data layer — C codecs]
    DAT[.dat loaders]
    GFX[.32 / .anm codecs]
    STR[str.dat]
  end
  SDL --> plat
  ACE --> plat
  plat --> core
  core --> data

Loading

Implementation phases

1. Bootstrap (done) — 320×200 compositor (ScreenCompositor), title screen (intro.32 @ (3,0) + introclips.32 pegasus/peekers + nwcp.32 logo + book.32 menu on black), roster viewer (roster.dat), 2× SDL present. Menu text uses Mm2Font8x8.inc (plain ASCII). Title animation spec: EXTRACTED/docs/39-title-screen-animation.md. Character UI is pluggable — see 39-character-ui-view-create.md.
2. Data + state (in progress) — wire all .dat codecs; materialize A4 workspace (mm2_gamestate.h). Done: map.dat codec (mm2_map_codec.{h,c} + tools/mm2_map_codec.py), world/MapWorld (map+attrib, neighbor pages, screen-enter per 0x256E/0x923E), GameStateView (include/mm2/GameState.h: screen/x/y/facing
   • per-era calendar -$79DE/-$79CA), party launch → A4 apply.
3. 3D view + movement (Milestone 2 done) — 0x2900 hood renderer plus gameplay/Movement (turn @ 0x5838, step @ 0x5816, passability first gate @ 0x9424, screen edge @ 0x1D0A, time tick/light drain @ 0x69DC). Arrow/keypad → $F0..$F3 via PlaySessionInput (no WASD — doc 43 §1 rawkey table). Offline checks: view3d_middlegate_check, playscreen_golden, movement_middlegate_test, playsession_input_test, event_middlegate_test.
4. Exploration commands (Phase 2) — in-town input from doc 43: Ctrl-Q quit prompt ($12F4), Q Quick Ref party table ($595C via 0x907A), digits 1–8 in-game character sheet ($8C8A / $39B4) with digit-chain character switch, O/P right-column OPTIONS/Protect toggle (-$79B2), Protect panel Light/Magic/Forces from -$79AB..-$79A6 (0x5E28), C Controls modal (0x13CCE), sheet sub-keys E/R/D equip/remove/drop (class mask from items.dat), C/U/G/S/T stubbed toward ASM handlers. Play HUD chrome (PlayScreenChrome): black viewport/status/party fills, red -809E console box around the bottom party band (0x5600), and full-screen black + red border for Q Quick Ref / digit character sheet overlays. B/D/E/M/S/U exploration keys wired with status stubs; R Rest restores HP/SP (minimal stub toward 0x19E20). Codecs: mm2_items_codec.{h,c} + tools/mm2_items_codec.py.
5. Scripted scene graphics (Phase 4+) — events/ScriptedSceneEngine drives castle/scene illustration beats separate from the event VM (doc 46-scripted-scene-graphics.md): Corak intro (viewport ghost overlay + loc 60 str[8] + OPTIONS panel) and Guardian Pegasus C2 (intro.32 full-sheet blit — not introclips title cels —
   • loc 11 str[5] + Protect panel). Wired into GameSession (auto-queue on new-game Middlegate / first enter map 11; debug Ctrl+G / Ctrl+P). Offline demos: scripted_corak.png, scripted_pegasus.png via event_op_demo. OP_0B wired: ServiceSignResolver + ViewportAnmOverlay (62.anm blacksmith demo). GAP: Corak ghost castle-bytecode confirm (remake uses 51.anm candidate), mode $17 placement table A4-$56E, party byte 0x74 bit 0x40 pegasus gate, castle tile hook 0x78A8.
6. Event processing (Phase 4 — VM) — events/EventRuntime is the authoritative remake of the event VM (~99% ASM-faithful): loader 0x92F2, init 0x1754A, scanner 0x175E2, dispatch 0x172CA for opcodes 0x00..0x32 (dispatchOp + helpers). Docs 07-event-script-opcodes.md / 08-event-runtime.md match the C++. Text via EventTextView; town services via EventTownServices / TownServiceMenu; encounters via EventCombatEncounter. Wired into GameSession::tick() after movement (-$7952 latch). Offline: event_middlegate_test, event_op_demo → build/event_demos/.
7. Main loop — 0x1280 mode dispatch (overland, town, combat, menus).
8. Combat — round loop, player bar, monster AI, rewards.
9. Audio — Desktop: pre-rendered WAVs from EXTRACTED/audio/ via SDL (mm2::audio, see doc 58). Amiga: Paula/audio.device port still TODO (AudioStub.cpp no-op).
10. Copy protection — externalize globe/disk strings (already extracted to EXTRACTED/embedded_strings.json).

RE references: EXTRACTED/docs/README.md, EXTRACTED/mm2.capstone.annotated.asm, per-location events in EXTRACTED/docs/events/.

Build (desktop / SDL2)

Requires CMake ≥ 3.16, C++17, network on first configure (SDL2 fetched via FetchContent).

cd game
cmake -S . -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build
./build/mm2 ../          # pass MM2 data directory (contains map.dat, town.32, …)
./build/mm2 ../ --ui=stub   # text-only character UI fallback

Character UI plugin

View Party (P) and Create (C) use a swappable layer (game/include/mm2/ui/):

Backend	Select
AmigaClassic (default)	--ui=classic, MM2_UI=classic, or -DMM2_UI=classic
Stub (text overlay)	--ui=stub, MM2_UI=stub, or -DMM2_UI=stub

Requires book.32 in the data directory for the classic sheet backdrop. See EXTRACTED/docs/39-character-ui-view-create.md.

Validate .32 decode (C codec vs Python reference):

cmake --build build
python ../tools/test_image32_golden.py --data-dir ..

Build (Amiga / ACE)

Same setup as ../Amiga/LandsOfLore: VS Code “Amiga Debug” (BartmanAbyss amiga-debug) provides m68k-amiga-elf-gcc, elf2hunk, and sys-include. The toolchain is auto-detected under %USERPROFILE%/.vscode/extensions/bartmanabyss.amiga-debug-* (override with -DAMIGA_VSCODE_BIN=…/bin/win32).

cd game
cmake --preset m68k-bartman-1.8.2
cmake --build build/m68k-bartman-1.8.2 --parallel
# -> build/m68k-bartman-1.8.2/mm2.exe (ELF2HUNK hunk executable)

Each Amiga link copies all *.dat, *.32, and *.anm from the MM2 repo root (../ relative to game/) into the same folder as mm2.exe, so the default data dir . matches WinUAE’s working directory. Rebuild after you change data files on disk. Optional: still pass ../../.. (or another path) as argv[1] if you prefer not to copy.

Presets live in CMakePresets.json; toolchain files in cmake/ (mm2-m68k-bartman.cmake, AmigaCMakeCrossToolchains/m68k-bartman.cmake). ACE is fetched from AmigaPorts/ACE main with ACE_USE_AGA_FEATURES enabled. VS Code kit: .vscode/cmake-kits.json + amiga.json.

Amiga uses -fno-exceptions -fno-rtti and CppStdCompat.h instead of libstdc++.

6bpp AGA screen (LoL screen.c pattern, TAG_VPORT_BPP 6 not LoL’s 8): src/platform/amiga/mm2_amiga_display.c, defines in include/mm2/platform/amiga/Mm2AmigaConfig.h. Rendering is planar end-to-end (mm2_amiga_planar.c): .32 assets decode straight to bitplanes and blit via ACE — no chunky RGBA buffer and no c2p needed. presentFrame() ignores the RGBA argument and just paces/refreshes the display.

Conventions

• Endianness: .dat multibyte fields are little-endian on disk (see root CLAUDE.md).
• Graphics: planar 5-bp .32 / .anm image chunks — mm2_image32_codec.c.
• Naming: lifted routines keep sub_<addr>_<purpose> until fully understood.
• No Blitz3D: original 68k ASM is the source of truth for runtime behaviour.