Mizu is an accurate Gameboy emulator built in Rust.
- Emulating The original gameboy (DMG) and gameboy color hardware.
- Passing most hardware tests (see TESTING.md).
- Bettery save support.
- Control SRAM save file and ability to disable SRAM save.
- Accurate RTC emulation for MBC3 mapper.
- Accurate APU emulation with 48KHz audio.
- SFML gui front-end.
- Robust testing framework for continous testing.
- Easily change emulation speed.
- Functional mappers:
- NoMapper
- MBC1
- MBC2
- MBC3
- MBC5
- Printer emulation
- Save states
The SFML front-end provide these keyboard bindings:
| Key | Gameboy |
|---|---|
| J | B |
| K | A |
| U | Select |
| I | Start |
| W | Up |
| S | Down |
| A | Left |
| D | Right |
| Key | Function |
|---|---|
| Enter | A+B+Select+Start* |
| + | Increase 5 to FPS** |
| - | Recude 5 from FPS** |
| P | Open Printer |
| (NUM1~NUM0) | Save state |
| Shift + (NUM1~NUM0) | Load state |
| C | Output All audio channels (default) |
| V | Output Pulse1 audio channel only |
| B | Output Pulse2 audio channel only |
| N | Output Wave audio channel only |
| M | Output Noise audio channel only |
* I made this because in
Zelda: Link's awakeningyou need to press all of these buttons on the same frame to bring the save menu, which is annoying.
** FPS here is not the same with normal games FPS, where low FPS just makes the game laggy, here FPS control the emulation speed. Normally it will run on
60FPS. If the user set FPS to30it will emulate in half the speed, this include audio, and CPU emulation.
| Key | Function |
|---|---|
| C | Clear current image buffer |
| S | Save image buffer to file |
Gameboy Printer is a serial device that can be connected to the gameboy and used by some cartridges to print images. Popular cartidges that uses it are:
- Gameboy Camera.
- Zelda: Link's Awakening DX (to print images from the album).
- Pokemon (several versions) (to print pokemon info from the Pokedex).
The printer can be opened by pressing the P key.
The printer emulation allows to save the printed images into disk. The window
will only show 160x144 pixels, but the image is scrollable.
Save state is a very useful features emulators should have, it allows
to save the state of the whole emulator at any point in time and be loaded
any time later. mizu's save states files are saved in these folders:
Linux: /home/<user>/.local/share/mizu/saved_states
Windows: C:\Users\<user>\AppData\Local\Amjad50\Mizu\data\saved_states
macOS: /Users/<user>/Library/Application Support/Amjad50.Mizu/saved_statesThe structure of the save file is at version 2:
| Offset | Size | Field |
|---|---|---|
| 0x00 | 4 | MAGIC: "MST\xee" (4D 53 54 EE) |
| 0x04 | 8 | save state file version |
| 0x0C | 32 | cartridge sha256 hash |
| 0x2C | variable | zstd default level compressed saved state |
There is no migrations between file versions (except from 1 to 2), that means
that a file saved from a past version of the emulator will not be able to be loaded
in a future version of the emulator.
(If any suggestions on how we can achieve this, you are welcome to open a PR).
The hash is used to make sure that we are loading for the same game.
The zstd compression appeared in version 2, that is the reason we can load version s
by loading with decompression. The compressed content, is the content we get
by using the save_state library.
For installing or building mizu we would use cargo.
If you want to use the development version of mizu you can build the project
yourself. After downloading/cloning the repository, it can be build with:
$ cargo build
With release option:
$ cargo build --release
If you want to use the latest stable version from crates.io:
$ cargo install mizu
Why not?. it is fun and educational, but even though I'm planning to make it as accurate as I can. If you want to see cool emulators, check my previous work Plastic.