teskje/goomba

A cycle-accurate GameBoy emulator written in Rust

Goomba

Goomba is a GameBoy emulator written in Rust.

Try it at https://teskje.github.io/goomba!

Usage

Goomba can run natively on desktop platforms and inside the browser.

Desktop

You can run Goomba natively using the cargo run command. It expects you to specify the path to a ROM (.gb) file:

$ cargo run --release -- roms/zelda.gb 

This opens a window showing the GameBoy display.

Controls are:

Joypad Button	Keyboard Key
Up	Arrow Up
Down	Arrow Down
Left	Arrow Left
Right	Arrow Right
A	x
B	z
Start	Enter
Select	Backspace

Upon quitting the emulator, a dialog opens that allows you to save the current cartridge RAM. Saving the RAM is necessary to be able to continue playing from in-game save points. To do so, specify the .gb-ram file as an additional argument to the cargo run command:

$ cargo run --release -- roms/zelda.gb --ram-path roms/zelda.gb-ram

You can also save a snapshot of the game by pressing ctrl-s. This opens a dialog that lets you save a .gb-save file, which can be used to later load the same game state again:

$ cargo run --release -- roms/zelda.gb-save

Note that .gb-save files are generally not compatible across different code versions.

Browser

To run Goomba in the browser, you need to first install the web bundler trunk. Then run it to serve Goomba locally:

$ trunk serve --release web/index.html
[...]
2023-05-21T14:03:06.846895Z  INFO ✅ success
2023-05-21T14:03:06.847740Z  INFO 📡 serving static assets at -> /
2023-05-21T14:03:06.847797Z  INFO 📡 server listening at http://127.0.0.1:8080

At http://127.0.0.1:8080 you are now presented with Goomba's web UI.

Use the leftmost menu button to load a ROM to play. The keyboard controls are the same as for desktop. On mobile devices that don't have a keyboard, you can control the game using the joypad instead.

You can save the cartridge RAM using the "save" button in the menu. The resulting .gb-ram file can be provided when you next load the game through the "load" button. Be sure the select both the .gb and the .gb-ram file in the file dialog.

TODOs

• Audio emulation
• GameBoy Color support