Another Gameboy Emulator

C project, rendering through SDL.

Current status

Most of Game Boy games will NOT work. Known to be playable games, with glitches are: Tetris, Dr.Mario.

Features

Simple joypad support
Simple save/restore function
Embedded simple command-line debugger

Z80 GameBoy CPU

All the CPU instructions are now implemented
Code is auto-generated
- /resources/table_gb.html is the main source of data
- generator is composed of /tools/{base_gen,cb_gen,gen_z80_instructions}.sh
Current status: all CPU instruction tests but 02-interrupt, from the blargg test suite are passing.

TODO

GPU
- Background rendering is still messy, need optimization and code clearing
- Sprite rendering is basic => need to implement sprite tile options
- Troobleshoot scrolling issues
Sound support
Serial link support

How to

Build

Under Debian 9 (should work with other linux distributions derived from Debian):

apt-get install libsdl2-dev cmake
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE:STRING=Release
make

To enable the built-in debugger

cmake ../emgb -DCMAKE_BUILD_TYPE:STRING=Release -DUSE_CONSOLE_DEBUGGER=ON
make

Then type <Ctrl>+C to enter the debugger and then type help to get started.

Usage

./gb ROM_PATH

Keys used are:

W: start
X: select
V: A
C: C
arrows for D-pad
F1: save game state
F2: restore game state

Configuration

Everything lies in the ~/.emgb/ directory.

Editing the config file allows to change keybindings, colors... Most configuration entries should be self-explicit.

Lines must have the form key=value, with whitespace characters not stripped and no support for comments.

Colors can be given in hexadecimal value 0xRRGGBB.

Key names are those used by the SDL function SDL_GetKeyName. Most of the time, it's the character itself, in uppercase if relevant. Please see the SDL source code here and there for more information.

Use a joypad

Run

mkdir -p ~/.emgb
./joypad_mapping ~/.emgb

A configuration file, named after your joypad, will be created in ~/.emgb. You can test the joypad configuration with

./joypad_mapping --test ~/.emgb

Then launch normally a game, for example

./gb ../roms/Tetris.gb

Then you should see lines ressembling what follows:

looking for /home/nicolas/.emgb//8bitdo_sfc30_gamepad.mapping
loaded mapping successfully

which indicate that your joypad has been properly configured and detected.

ncarrier/emgb