This repository contains a Gameboy emulator core with a choice of three frontends:

• Native binary, only tested on Linux
• asm.js, compiled using Emscripten
• Google Chrome Native Client (NaCl) application

Online demos are available at http://ajor.co.uk/gameboy/

The Gameboy's direction keys are mapped to the arrow keys.

Start button = enter
Select button = backspace
A button = z
B button = x

Save files are compatible with other popular Gameboy emulators.

Audio support is not complete.

Memory bank controllers (MBCs) 1 and 3 are the only ones currently supported, although the vast majority of Gameboy games use one of these two (or no MBC at all). The Real Time Clock (RTC) used in MBC3 is not implemented, so games which use it to keep track of time while the Gameboy is powered off will not function correctly in some aspects.

Scanlines are rendered individually, with each scanline being rendered in one go at the end of the H-Blank period. This means games which modify the data to be drawn mid-scanline do not render correctly - e.g. Prehistorik Man title sequence.

TODO results

• A C++14 compiler
• CMake 2.8.12+
• GLFW3
• GLEW

Compile using CMake (defaults to release configuration):

mkdir build
cd build
cmake ../
make

./gb rom

• Emscripten SDK
• Node.js
• CMake 2.8.12+

Compile using CMake, substituting the path to the Emscripten.cmake toolchain file on your system:

mkdir build
cd build
cmake ../ -DCMAKE_TOOLCHAIN_FILE=/usr/lib/emscripten/cmake/Modules/Platform/Emscripten.cmake
make

Place glfw/emscripten.html and the generated gb.js and gb.js.mem files in the same directory and open in a web browser.

• Chrome Native Client SDK
• CMake 2.8.12+

Compile using CMake, replacing [NaCl toolchain bin dir] with the path to the PNaCl toolchain directory for your platform, e.g.: ~/nacl_sdk/pepper_46/toolchain/linux_pnacl/bin

mkdir build
cd build
cmake ../ -DNACL_TOOLCHAIN_BIN=[NaCl toolchain bin dir] -DCMAKE_TOOLCHAIN_FILE=../nacl/NaCl.cmake
make

Place the generated gb.pexe binary along with nacl/index.html and nacl/gameboy.nmf from this repository on a web server and open in Google Chrome.

It can be run from your own computer using Python's HTTP server module:

python2 -m SimpleHTTPServer

or:

python3 -m http.server