Battletoads in Battlemaniacs Recomp

Battletoads in Battlemaniacs Recomp

A native recompilation of Battletoads in Battlemaniacs (USA), built on snesrecomp.

Battletoads in Battlemaniacs is a beat 'em up platform game developed by Rare for the Super Nintendo Entertainment System. Part of the Battletoads series, the game was released in North America by Tradewest in June 1993, in Europe by Nintendo in October 1993 and in Japan by Masaya on January 7, 1994.

Description from Wikipedia, CC BY-SA 4.0.

You must legally own a copy of the game. No ROM data is distributed with this project, in the repository or in any release. The recompiled C is generated locally from your own copy and is never committed.

☕ Keep the ports coming

This project is free and always will be. Every port in this series, Battletoads in Battlemaniacs included, is built with many hours of AI-assisted reverse engineering, and that AI time is paid. If you enjoy playing it, a coffee at buymeacoffee.com/mpolizel keeps the AI running so more SNES games can be ported to native Recomp. Any amount helps, and thank you!

Download (ready-to-run Windows build)

Get the latest battletoads-<version>-windows-x64.zip from the Releases page.

The zip is a setup pack: it contains the launcher, the recompiler and this source tree (with the framework patches already applied), but no game data. On first run:

1. Unzip anywhere and start BattletoadsInBattlemaniacsSNESRecomp.exe.
2. Let it download the portable build tools (one time per machine), or point it at a cmake-clang-v1 zip you already have.
3. Pick your own Battletoads in Battlemaniacs (USA).sfc (CRC32 617ac925).
4. Press Generate & rebuild. The playable game is built into build/ and started; run it from there afterwards.

In the launcher, Settings → Shader lists the scanline, CRT and upscaler presets; choosing one switches the renderer to OpenGL automatically. A fresh install starts with no shader (the plain picture), the lightest option for any graphics card; pick a CRT or upscaler preset there if yours has room. Your choice is saved in config.ini and kept. The upscalers include ScaleFX and the neural NNEDI3 presets.

During play, Ctrl+L (or Select+L3 on a controller) reopens the launcher: shader, window scale, volume and controls apply when you press Resume, without restarting the game. I cycles the audio interpolation between Gaussian (the console's own, the default), Cubic (crisper highs) and Sinc; it only changes what you hear, never the game, and the choice is saved in audio_interpolation.txt.

On laptops with two graphics cards (NVIDIA Optimus, AMD switchable graphics) the game asks the driver for the dedicated one. If it still runs slowly, set the game's executable to High performance in Windows Settings → System → Display → Graphics.

Updates

With Check for updates on start ticked (the default; on the launcher's main screen, next to Skip launcher on boot), the game asks GitHub for the latest release when it starts and offers to install a newer one. Accepting closes the game, downloads the new setup pack, copies it over the install folder and reopens the setup window: press Generate & rebuild. Nothing is deleted; build\ (the rebuilt game, save states, config.ini, keybinds.ini) and rom.cfg are kept. Untick the box to turn the check off (saved in update.ini).

Your saves are never lost or broken by an update. Save states made by any earlier release keep working in every later one. Before installing, the updater copies build\saves\ to save-backups\<date>_before_<version>\ and never deletes those copies; save files are left out of the copy, and if they changed anyway the backup is put back. Every release is checked against the one before it with tools/check_update_compat.ps1, which builds the previous release, makes a save state with it, installs the new pack with the previous release's own updater and rebuilds; it fails unless every save file is byte-identical and the new build continues the old save state.

See CHANGELOG.md for what changed in each release.

Status

Boots through the Tradewest and Rare logos, the title screen and the waving copyright flag into player select, the intro cutscene and the first level (Ragnarok's Canyon). Most code still runs through the snesrecomp interpreter; later levels and two-player play are not yet verified. See Porting from here.

Framework patches

patches/ holds changes to the snesrecomp and recomp-ui submodules. Reapply them after updating the submodules:

git -C snesrecomp apply ../patches/snesrecomp-nmi-idle-loop-wai.patch
git -C snesrecomp apply ../patches/snesrecomp-nmi-wai-in-handler.patch
git -C snesrecomp apply ../patches/snesrecomp-opt-bg3-row.patch
git -C snesrecomp apply ../patches/snesrecomp-raster-oam-and-hdma.patch
git -C snesrecomp apply ../patches/snesrecomp-audio-interpolation.patch
git -C snesrecomp apply ../patches/snesrecomp-glsl-passprev-and-vao.patch
git -C snesrecomp apply ../patches/snesrecomp-shader-forces-opengl.patch
git -C recomp-ui apply ../patches/recomp-ui-host-toggle.patch

snesrecomp-nmi-idle-loop-wai.patch is required for this game, as for the Donkey Kong Country ports (the same Rare engine pattern): the NMI handler resets the stack, runs the game and falls into a WAI / BRA idle loop ($80:86C2) instead of returning with RTI. Without the patch that loop ran to the interpreter's step cap and the game froze on the player-select screen. The handler is then the game's main program, so raster IRQs interrupt it as they would the main loop: the HUD split (IRQ at line 33) used to wait for the game logic to finish, and in busy scenes drew a band of HUD tiles over the level.

snesrecomp-nmi-wai-in-handler.patch makes any WAI inside an interrupt handler halt until the next interrupt, as on hardware. Here a scene change ends in WAI / BRA at $80:8DF5 while still inside NMI; the interpreter skipped the WAI and spun to its step cap, costing that frame. In Donkey Kong Country (same Rare engine) the same case after saving left the screen black.

snesrecomp-opt-bg3-row.patch fixes offset-per-tile (BG mode 2). The PPU read the BG3 offset map one line above BG3VOFS, which at VOFS 0 is the last row of the map: the waving copyright flag after the title screen came out cut into seams, with the right edge wrapped onto the left.

snesrecomp-raster-oam-and-hdma.patch is the renderer fix shared with the Super Mario Kart and Donkey Kong Country ports: per-line sprite tables, HDMA set up in vblank, and vblank writes kept in their own field. It also counts HDMA's first transfer, made in V=0's H-blank, as a table line, as the hardware does. Every HDMA split landed one line late without it (on Donkey Kong Country 2's island map the late layer split drew a bright line across the screen).

snesrecomp-audio-interpolation.patch adds the Cubic and Sinc audio interpolation (I key). They resample the dry output only; the echo buffer, OUTX, pitch modulation and save states stay those of the console's Gaussian filter, so the game runs identically in every mode.

snesrecomp-glsl-passprev-and-vao.patch fixes two shader bugs: a pass that reads PassPrev<n> back to the game frame got nothing (ScaleFX drew black), and switching to no shader mid-game drew a black screen because the shader path left the plain path's vertex attributes disabled.

recomp-ui-host-toggle.patch lets a title add one checkbox of its own beside "Skip launcher on boot"; this project uses it for the update check.

ROM identity

File	Battletoads in Battlemaniacs (USA).sfc
Publisher	Tradewest
Developer	Rare
Year	1993
Mapping	lorom
Region	USA (North America)
Coprocessor	none
CRC32	617ac925
SHA-256	b0dbd4d7e5689c32234e80b0c5362ef67c425ab72d6ddb49d1cb1133ef630ef7

tools/regen.sh refuses to run against anything else, so a mismatched revision fails immediately instead of producing subtly wrong output.

Build

git submodule update --init --recursive
bash tools/regen.sh --rom "/path/to/Battletoads in Battlemaniacs (USA).sfc"
cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j

The ROM does not have to live in the repository — keeping it on your own drive is the better habit, and SNESRECOMP_ROM sets the path once for a shell. Without either, tools/regen.sh finds the ROM at the repo root, then the path the setup wizard recorded in rom.cfg; .gitignore blocks both from ever being committed.

tools/regen.sh verifies the ROM, generates src/gen/*.c, and re-syncs recomp/funcs.h. Re-run it whenever you change anything under recomp/.

The Windows build is a window app: diagnostics go to BattletoadsInBattlemaniacsSNESRecomp.log beside the executable. -DBT_CONSOLE=ON brings the console back for debugging.

Run

./build/BattletoadsInBattlemaniacsSNESRecomp                    # launcher picks the ROM
./build/BattletoadsInBattlemaniacsSNESRecomp "/path/to/Battletoads in Battlemaniacs (USA).sfc"

With no ROM on the command line the build opens the recomp-ui launcher: a ROM picker with a verification badge, plus display / audio / input settings. Your choice is cached in rom.cfg beside the executable, so the next launch opens on it and "Skip launcher on boot" makes it immediate.

Either way the ROM is checked against the digests above before anything boots — a dump that could not have produced this build is refused at the door rather than mis-executing ten frames in.

Layout

Path	What lives there
recomp/	Analysis input: bank*.cfg, symbols.toml, generated funcs.h
rom_identity.txt	ROM digests — read by the build, tools/regen.sh and CI
src/	Host code you own: main.c, game_rtl.c, bt_update.c
src/gen/	Generated C. Never committed — regenerate locally
assets/shaders/	Scanline, CRT and upscaler presets for the launcher
patches/	Changes to the framework submodules (see above)
snesrecomp/	Framework submodule (owns lib/recomp-net, lib/retcomm-rbengine)
tools/	regen.sh — the ROM → C pipeline; import_libretro_shaders.py
scripts/	package_release.sh — player-facing zip
framework_pins.txt	Exact framework commits this project was scaffolded against

Porting from here

The scaffold stops where the game-specific work starts. In rough order:

1. Make it boot. src/game_rtl.c holds the frame driver. It starts on the framework's beam-aligned driver (snesrecomp/runner/src/beam_frame_driver.h): one frame per PPU field, interrupts taken where the beam latches them, the field rasterized from the raster journal.
2. Name things. Add entries to recomp/symbols.toml as you identify routines, then re-run tools/regen.sh. Set emit = true to promote one into ahead-of-time analysis; leave it false to keep it interpreted. See recomp/README.md.
3. Resolve dispatch misses. After every run, deal with unresolved indirect targets before anything else — they are the reason a port diverges, and they are cheap to fix early.
4. Never synthesise a result to get past uncovered code, and never edit src/gen/ by hand. Fix the config or the framework and regenerate.

Multiplayer

Two players, one controller per port (1 Player, 2 Players A and B modes).

License

This project's own source is under the MIT license in LICENSE. The framework carries its own terms (PolyForm Noncommercial 1.0.0) — see snesrecomp/LICENSE and snesrecomp/THIRD_PARTY_ATTRIBUTION.md; the changes in patches/ apply to that framework and fall under its terms. The shaders under assets/shaders/_libretro/ come from libretro/glsl-shaders and keep each author's license in their file headers. None of these cover the game data, which is not distributed here.

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