jendrikw / binjgb

Gameboy emulator implemented in C

binjgb

A simple GB/GBC emulator.

Features

• Runs in the browser using WebAssembly
• Hacky-but-passable CGB support!
• Cycle accurate, passes many timing tests (see below)
• Supports MBC1, MBC1M, MMM01, MBC2, MBC3, MBC5 and HuC1
• Save/load battery backup
• Save/load emulator state to file
• Fast-forward, pause and step one frame
• Rewind and seek to specific cycle
• Disable/enable each audio channel
• Disable/enable BG, Window and Sprite layers
• Convenient Python test harness using hashes to validate
• (WIP) Debugger with various visualizations (see below)

DMG Screenshots

CGB Screenshots

Debugger Screenshots

Cloning

Use a recursive clone, to include the submodules:

$ git clone --recursive https://github.com/binji/binjgb

If you've already cloned without initializing submodules, you can run this:

$ git submodule update --init

Building

Requires CMake and SDL2. Debugger uses dear imgui, (included as a git submodule).

Building (Linux/Mac)

If you run make, it will run CMake for you and put the output in the bin/ directory.

$ make
$ bin/binjgb foo.gb

You can also just use cmake directly:

$ mkdir build
$ cd build
$ cmake ..
$ make

Building (Windows)

When building on Windows, you'll probably have to set the SDL2 directory:

> mkdir build
> cd build
> cmake .. -G "Visual Studio 15 2017" -DSDL2_ROOT_DIR="C:\path\to\SDL\"

Then load this solution into Visual Studio and build it. Make sure to build the INSTALL target, so the exectuables are built to the bin directory.

Building WebAssembly

You can build binjgb as a WebAssembly module. You'll need an incoming build of emscripten. See https://github.com/kripken/emscripten/wiki/WebAssembly and http://kripken.github.io/emscripten-site/docs/building_from_source/index.html#installing-from-source.

Put a symlink to Emscripten in the emscripten directory, then run make.

$ ln -s ${PATH_TO_EMSCRIPTEN} emscripten
$ make wasm

Changing the Build Configuration

If you change the build config (e.g. update the submodules), you may need to run CMake again. The simplest way to do this is to remove the out/ directory.

$ rm -rf out/
$ make

Running

$ bin/binjgb <filename>
$ bin/binjgb-debugger <filename>

Keys:

Action	Key
DPAD-UP	↑
DPAD-DOWN	↓
DPAD-LEFT	←
DPAD-RIGHT	→
B	Z
A	X
START	Enter
SELECT	Tab
Quit	Esc
Save state	F6
Load state	F9
Toggle fullscreen	F11
Disable audio channel 1-4	1-4
Disable BG layer	B
Disable Window layer	W
Disable OBJ (sprites)	O
Fast-forward	Lshift
Rewind	Backspace
Pause	Space
Step one frame	N

Running tests

Run scripts/build_tests.py to download and build the necessary testsuites. This works on Linux and Mac, not sure about Windows.

scripts/tester.py will only run the tests that match a filter passed on the command line. Some examples:

# Run all tests
$ scripts/tester.py

# Run all tests mooneye tests
$ scripts/tester.py mooneye

# Run all gpu tests
$ scripts/tester.py gpu

Test status

See test results