GBLib

GBLib is a cross-platform Nintendo GameBoy emulator written as a portable C++ library. Easily inject your platform specific dependencies to run anywhere.

For an example on how to build an application on top of GBLib refer to GBSdl and GBAndroid.

How do I use GBLib to make an application?

Almost all of the core emulation logic is contained inside the library itself. The only pieces you need to write are implementations to the interfaces defined in the interface directory. These implementations are for bridging your specific graphics and input handling frameworks with the emulator.

IEventHandler.h

// Processes input events to send to the joypad controller.
class IEventHandler
{
public:
    // Polls for input events, and sets the appropriate button presses on the joypad controller.
    virtual void HandleInput(JoypadController* joypadController) = 0;

    // Should the emulator quit?
    virtual bool ShouldQuit() = 0;

    // Indicates what speed multiplier the emulator should actively run at.
    virtual int SpeedMultiplier() = 0;
};

IGraphicsHandler.h

// Handles the graphics data sent from the PPU. Interface is injectable to GraphicsManager to allow
// for different rendering dependencies.
class IGraphicsHandler
{
public:
    // Initialize any dependenices. Called when LCD screen is powered on.
    virtual void Init() = 0;

    // Clear the screen (usually draw all white pixels to the screen).
    virtual void Clear() = 0;

    // Called from the ppu after all scanlines have been buffered, pixelBuffer is an array of pixels 
    // in little endian ARGB8888 format.
    virtual void Draw(const u32* pixelBuffer, int width, int height) = 0;

    // Quit and release any resources for the graphics handler.
    virtual void Quit() = 0;
};

ISerialHandler.h

// Sends bytes from a master GameBoy using an internal clock to an secondary GameBoy.
// Connection of virtual serial cable between two GameBoys should happen asyncronously
// on a seperate thread from that of the GameBoy emulator.
class ISerialHandler
{
public:
    // Returns true if a virtual "serial cable" is connected to this GameBoy.
    virtual bool IsSerialConnected() = 0;

    // Sends a byte to the other GameBoy.
    virtual void SendByte(Byte byte) = 0;

    // Returns true if a byte was recieved from another GameBoy.
    virtual bool ByteRecieved() = 0;

    // Blocks, waiting to recieve a new byte from other GameBoy.
    virtual Byte RecieveByte() = 0;
};

These interfaces have been implemented using the Simple DirectMedia Layer (SDL) in GBSdl.

How to Build

In the root directory run CMake.

cmake .

CMake will generate platform specific build tools, e.g. a Makefile on Linux or a Visual Studio Solution in Windows.

All source files reside in the src directory and header files reside in the include directory.

License

GBLib is released under the MIT license.

Testing

To run unit tests, use the test project listed under the test folder. To run Blargg's GB Test Roms, load any of the roms under rom\gb-test-roms sub module.

Media