Digimon World 3 Recomp

Digimon World 3 (PS1, USA) running as a native program on your PC. It isn't an emulator. The game's code was translated ahead of time into code your machine runs directly, so it starts fast, sits well on handhelds and gives us room to do things an emulator can't do cleanly.

You need your own copy of the game. Nothing from the disc is in this repo or in any download from it.

Status: beta. The whole game boots and plays on Linux, macOS (Apple silicon) and Windows. Expect rough edges, and please report them.

Features

• Three looks:

  Original (exactly what the PlayStation showed) Enhanced (same look, sharper, no dither, no wobbling polygons) Remaster (everything cranked).

• 3D rendered at up to 8x the original resolution.

• HD backgrounds. The field maps are pre-rendered pictures, so we can swap in AI-upscaled ones. You make them from your own disc on your own PC, the setup walks you through it, and it's optional.

• Seamless maps. No more dark squares popping in at the edges of a field while you walk.

• Widescreen at 16:9, 16:10 or 21:9 without stretching the picture.

• HDR, FSR, SMAA, sharpening, colour grading, and a CRT look if you want scanlines.

• Save states anywhere, on top of the normal memory card saves (those are plain files you can back up).

• Fast-forward, or run the whole game at 2x to 4x with the music staying in tune.

• Text speed up to instant, encounter rate (half, double or off), an XP multiplier and a god mode. All of it is off by default, so the game plays like the original until you say otherwise.

• Separate music and effects volume.

• Controller support with Xbox, PlayStation or Nintendo button prompts, and everything is rebindable.

• Borderless, windowed or exclusive fullscreen on whichever monitor you pick.

Every option lives in an in-game settings screen, and in a plain settings.toml.

Running it

1. Get a dump of your own disc as a .cue / .bin pair.
2. Start the program. First launch opens a setup window that asks for the .cue, checks it's the right game (SLUS-01436) and remembers it. Then it builds the game from your disc on your PC. That takes a minute or a few, it only happens once, and nothing gets downloaded for it. --setup opens the window again.
3. Optional: say yes to HD backgrounds in the same window. It downloads an upscaler and a model, checks them against fixed hashes, and builds a pack from your disc. That takes a long time and needs a Vulkan GPU, but you can cancel and pick it up later.

Technical

The recompiler reads the main executable and all 263 overlays off the disc, finds every function, and writes C for each one. That C is compiled for your platform and linked against a runtime that does the rest of the console: GPU, SPU, GTE, CD drive, memory cards, timers, DMA and a native BIOS. No CPU emulation, no interpreter, and no fallback if the recompiler missed something. A missing function stops the game with a clear message.

• Renderers: Metal, Vulkan and Direct3D 12 through plume, plus a software rasterizer. All 3D and post-processing happens on the GPU.
• Platforms: Linux x86-64 and arm64, macOS on Apple silicon, Windows x64.
• Save states record where the game is in the original's addresses, so they don't depend on which build made them.
• The generated C is architecture neutral, so one machine can produce it for the others.
• Licensed GPL-3.0.

Building

The recompiled code comes from your disc.

1. Put your disc at game/Digimon World 3 (USA).bin / .cue (git-ignored), or point -DDW3_GAME_DIR= at its folder.

2. Generate the recompiled code. Do this once, and again when config/dw3.toml or the recompiler changes:

   cmake --preset <preset>
   cmake --build --preset <preset> --target dw3extract psxrecomp
   build/<preset>/tools/dw3extract/dw3extract "game/Digimon World 3 (USA).cue" extract game/extracted
   cmake --build --preset <preset> --target recompile      # writes generated/
   

3. Configure again so CMake sees generated/, then build and test:

   cmake --preset <preset>
   cmake --build --preset <preset>
   ctest --preset <preset> -LE scenario -j8      # unit tests; -L scenario runs the in-game tests and needs the disc
   

The program ends up at build/<preset>/app/dw3recomp.

Platform	Presets
Linux x86-64	linux-x64-debug, linux-x64-release
Linux arm64	linux-arm64-* (native), linux-arm64-cross-* (from x86-64, tests under qemu)
macOS (Apple silicon)	macos-arm64-debug, macos-arm64-release
Windows x64	windows-x64-debug, windows-x64-release (on Windows), windows-x64-cross-* (from Linux)

You need clang, CMake 3.24 or newer, Ninja, glslang and SDL3. On Linux you also need the Vulkan headers and loader. GoogleTest, toml++, zstd and plume are fetched for you. On Bazzite or Silverblue do all of this in a distrobox.

Without generated/ everything else still builds and the unit tests run (that is what CI does), but there's no game code in the program. It needs a game module instead.

Game modules

The recompiled code can also be built as a shared library and loaded at run time, with --module PATH. The library gets the runtime's services through a small table when it loads, so it has no link-time dependency on the program and loads the same way on every OS. -DDW3_BUILD_GAME_MODULE=ON builds one from generated/.

The packages contain the program and a small toolchain (a zig compiler plus two source files) and no game code. The setup recompiles your disc with the same recompiler as the build above, compiles the result with that toolchain and keeps the module in your user data folder, named after the recompiler version and the disc. dw3recomp --prepare does the same from the command line. Tagging v* runs the release workflow, which builds and tests every platform and publishes the packages as a pre-release.

Layout

Path	Contents
tools/psxdisc	cue/bin, raw sector, ISO9660 and PS-X EXE library
tools/dw3extract	disc lister and extractor, including the hidden AAA/ tree
tools/psxrecomp	MIPS R3000A to C recompiler
tools/texpack	texture pack builder for HD backgrounds
runtime/	console hardware, BIOS, game module loader, platform layer
app/	the program: window, input, settings, setup window, presenters
host/	boot and run logic shared by the app and the scenario runner
render/	GPU renderers and the software rasterizer
config/	recompiler configuration for DW3
tests/	unit tests and in-game scenarios
packaging/	macOS .app and dmg scripts, Windows and Linux packaging
docs/	architecture, building and settings

License

GPL-3.0. See LICENSE.