medusa

medusa is an emulator for running Nintendo DS, Game Boy Advance and Game Boy games. It aims to be faster and more accurate than many existing Nintendo DS and Game Boy Advance emulators, as well as adding features that other emulators lack. It also supports Game Boy and Game Boy Color games.

Up-to-date news and downloads can be found at mgba.io.

Features

• Highly accurate Game Boy Advance hardware support^[1].
• Partial DS hardware support^[1].
• Game Boy/Game Boy Color hardware support.
• Fast emulation for Game Boy and Game Boy Advance. Known to run at full speed even on low end hardware, such as netbooks^[2].
• Qt and SDL ports for a heavy-weight and a light-weight frontend.
• Local (same computer) link cable support.
• Save type detection, even for flash memory size^[3].
• Support for cartridges with motion sensors and rumble (only usable with game controllers)^[2].
• Real-time clock support, even without configuration.
• Solar sensor support for Boktai games.
• Game Boy Camera and Game Boy Printer support.
• A built-in GBA BIOS implementation, and ability to load external BIOS files. DS currently requires BIOS and firmware dumps^[2].
• Turbo/fast-forward support by holding Tab.
• Rewind by holding Backquote.
• Frameskip, configurable up to 10.
• Screenshot support.
• Cheat code support^[2].
• 9 savestate slots. Savestates are also viewable as screenshots^[2].
• Video, GIF and APNG recording.
• e-Reader support.
• Remappable controls for both keyboards and gamepads.
• Loading from ZIP and 7z files.
• IPS, UPS and BPS patch support.
• Game debugging via a command-line interface and GDB remote support, compatible with IDA Pro.
• Configurable emulation rewinding.
• Support for loading and exporting GameShark and Action Replay snapshots.
• Cores available for RetroArch/Libretro and OpenEmu.
• Many, many smaller things.

Game Boy mappers

The following mappers are fully supported:

• MBC1
• MBC1M
• MBC2
• MBC3
• MBC3+RTC
• MBC5
• MBC5+Rumble
• MBC7
• Wisdom Tree (unlicensed)
• Pokémon Jade/Diamond (unlicensed)

The following mappers are partially supported:

• MBC6
• MMM01
• Pocket Cam
• TAMA5
• HuC-1
• HuC-3

Planned features

• Networked multiplayer link cable support.
• Dolphin/JOY bus link cable support.
• M4A audio mixing, for higher quality sound than hardware.
• Re-recording support for tool-assist runs.
• Lua support for scripting.
• A comprehensive debug suite.
• Wireless adapter support.
• OpenGL renderer.
• HLE support for DS BIOS and DS ARM7 processor.
• Synthesizing a customizable DS firmware to avoid needing a dump.

Supported Platforms

• Windows Vista or newer
• OS X 10.7 (Lion)^[4] or newer
• Linux
• FreeBSD

The following platforms are supported for everything except DS:

• Nintendo 3DS
• Wii
• PlayStation Vita

Other Unix-like platforms, such as OpenBSD, are known to work as well, but are untested and not fully supported.

System requirements

Requirements are minimal^[2]. Any computer that can run Windows Vista or newer should be able to handle emulation. Support for OpenGL 1.1 or newer is also required, with OpenGL 3.2 or newer for shaders and advanced features.

Downloads

Downloads can be found on the official website, in the Downloads section. The source code can be found on GitHub.

Controls

Controls are configurable in the settings menu. Many game controllers should be automatically mapped by default. The default keyboard controls are as follows for GB and GBA:

• A: X
• B: Z
• L: A
• R: S
• Start: Enter
• Select: Backspace

DS default controls are slightly different:

• A: X
• B: Z
• X: S
• Y: A
• L: Q
• R: W
• Start: Enter
• Select: Backspace

Compiling

Compiling requires using CMake 3.1 or newer. GCC and Clang are both known to work to compile medusa, but Visual Studio 2013 and older are known not to work. Support for Visual Studio 2015 and newer is coming soon.

Docker building

The recommended way to build for most platforms is to use Docker. Several Docker images are provided that contain the requisite toolchain and dependencies for building mGBA across several platforms.

To use a Docker image to build mGBA, simply run the following command while in the root of an mGBA checkout:

docker run --rm -t -v $PWD:/home/mgba/src mgba/windows:w32

This will produce a build-win32 directory with the build products. Replace mgba/windows:w32 with another Docker image for other platforms, which will produce a corresponding other directory. The following Docker images available on Docker Hub:

• mgba/3ds
• mgba/switch
• mgba/ubuntu:xenial
• mgba/ubuntu:bionic
• mgba/ubuntu:cosmic
• mgba/ubuntu:disco
• mgba/ubuntu:eoan
• mgba/ubuntu:focal
• mgba/vita
• mgba/wii
• mgba/windows:w32
• mgba/windows:w64

*nix building

To use CMake to build on a Unix-based system, the recommended commands are as follows:

mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX:PATH=/usr ..
make
sudo make install

This will build and install medusa into /usr/bin and /usr/lib. Dependencies that are installed will be automatically detected, and features that are disabled if the dependencies are not found will be shown after running the cmake command after warnings about being unable to find them.

If you are on macOS, the steps are a little different. Assuming you are using the homebrew package manager, the recommended commands to obtain the dependencies and build are:

brew install cmake ffmpeg libzip qt5 sdl2 libedit pkg-config
mkdir build
cd build
cmake -DCMAKE_PREFIX_PATH=`brew --prefix qt5` ..
make

Note that you should not do a make install on macOS, as it will not work properly.

Windows developer building

MSYS2

To build on Windows for development, using MSYS2 is recommended. Follow the installation steps found on their website. Make sure you're running the 32-bit version ("MSYS2 MinGW 32-bit") (or the 64-bit version "MSYS2 MinGW 64-bit" if you want to build for x86_64) and run this additional command (including the braces) to install the needed dependencies (please note that this involves downloading over 1100MiB of packages, so it will take a long time):

For x86 (32 bit) builds:

pacman -Sy --needed base-devel git mingw-w64-i686-{cmake,ffmpeg,gcc,gdb,libelf,libepoxy,libzip,pkg-config,qt5,SDL2,ntldd-git}

For x86_64 (64 bit) builds:

pacman -Sy --needed base-devel git mingw-w64-x86_64-{cmake,ffmpeg,gcc,gdb,libelf,libepoxy,libzip,pkg-config,qt5,SDL2,ntldd-git}

Check out the source code by running this command:

git clone https://github.com/mgba-emu/mgba.git -b medusa medusa

Then finally build it by running these commands:

cd medusa
mkdir build
cd build
cmake .. -G "MSYS Makefiles"
make

Please note that this build of medusa for Windows is not suitable for distribution, due to the scattering of DLLs it needs to run, but is perfect for development. However, if distributing such a build is desired (e.g. for testing on machines that don't have the MSYS2 environment installed), running cpack -G ZIP will prepare a zip file with all of the necessary DLLs.

Visual Studio

To build using Visual Studio is a similarly complicated setup. To begin you will need to install vcpkg. After installing vcpkg you will need to install several additional packages:

vcpkg install ffmpeg[vpx,x264] libepoxy libpng libzip sdl2 sqlite3

Note that this installation won't support hardware accelerated video encoding on Nvidia hardware. If you care about this, you'll need to install CUDA beforehand, and then substitute ffmpeg[vpx,x264,nvcodec] into the previous command.

You will also need to install Qt. Unfortunately due to Qt being owned and run by an ailing company as opposed to a reasonable organization there is no longer an offline open source edition installer for the latest version, so you'll need to either fall back to an old version installer (which wants you to create an otherwise-useless account, but you can bypass temporarily setting an invalid proxy or otherwise disabling networking), use the online installer (which requires an account regardless), or use vcpkg to build it (slowly). None of these are great options. For the installer you'll want to install the applicable MSVC versions. Note that the offline installers do not support MSVC 2019. For vcpkg you'll want to install it as such, which will take quite a while, especially on quad core or less computers:

vcpkg install qt5-base qt5-multimedia

Next, open Visual Studio, select Clone Repository, and enter https://github.com/mgba-emu/mgba.git. When Visual Studio is done cloning, go to File > CMake and open the CMakeLists.txt file at the root of the checked out repository. From there, mGBA can be developed in Visual Studio similarly to other Visual Studio CMake projects.

Toolchain building

If you have devkitARM (for 3DS), devkitPPC (for Wii), devkitA64 (for Switch), or vitasdk (for PS Vita), you can use the following commands for building:

mkdir build
cd build
cmake -DCMAKE_TOOLCHAIN_FILE=../src/platform/3ds/CMakeToolchain.txt ..
make

Replace the -DCMAKE_TOOLCHAIN_FILE parameter for the following platforms:

• 3DS: ../src/platform/3ds/CMakeToolchain.txt
• Switch: ../src/platform/switch/CMakeToolchain.txt
• Vita: ../src/platform/psp2/CMakeToolchain.vitasdk
• Wii: ../src/platform/wii/CMakeToolchain.txt

Dependencies

medusa has no hard dependencies, however, the following optional dependencies are required for specific features. The features will be disabled if the dependencies can't be found.

• Qt 5: for the GUI frontend. Qt Multimedia or SDL are required for audio.
• SDL: for a more basic frontend and gamepad support in the Qt frontend. SDL 2 is recommended, but 1.2 is supported.
• zlib and libpng: for screenshot support and savestate-in-PNG support.
• libedit: for command-line debugger support.
• ffmpeg or libav: for video and GIF recording.
• libzip or zlib: for loading ROMs stored in zip files.
• SQLite3: for game databases.
• libelf: for ELF loading.

SQLite3, libpng, and zlib are included with the emulator, so they do not need to be externally compiled first.

Footnotes

[1] Currently missing features on GBA are

• OBJ window for modes 3, 4 and 5 (Bug #5)

Missing features on DS are

• Audio:
  • Master audio settings
  • Sound output capture
  • Microphone
• Graphics:
  • Edge marking/wireframe
  • Highlight shading
  • Fog
  • Anti-aliasing
  • Alpha test
  • Position test
  • Vector test
  • Bitmap rear plane
  • Large bitmap mode 6
  • 1-dot depth clipping
  • Vector matrix memory mapping
  • Polygon/vertex RAM entry count memory mapping
  • Rendered line count memory mapping
  • Horizontal scrolling on 3D background
  • Some bitmap OBJ mappings
  • DMA FIFO backgrounds
• Other:
  • Cache emulation/estimation
  • Slot-2 access/RAM/rumble
  • BIOS protection
  • Display start DMAs
  • Most of Wi-Fi
  • RTC interrupts
  • Manual IPC sync IRQs
  • Lid switch
  • Power management
  • Touchscreen temperature/pressure support
  • Various MMIO registers
  • DSi cart protections

[2] Many feature are still missing on the DS, including savestates, cheats, rumble, HLE BIOS, and more.

[3] Flash memory size detection does not work in some cases. These can be configured at runtime, but filing a bug is recommended if such a case is encountered.

[3] 10.7 is only needed for the Qt port. The SDL port is known to work on 10.5, and may work on older.

Copyright

medusa is Copyright © 2013 – 2020 Jeffrey Pfau. It is distributed under the Mozilla Public License version 2.0. A copy of the license is available in the distributed LICENSE file.

medusa contains the following third-party libraries:

• inih, which is copyright © 2009 – 2020 Ben Hoyt and used under a BSD 3-clause license.
• blip-buf, which is copyright © 2003 – 2009 Shay Green and used under a Lesser GNU Public License.
• LZMA SDK, which is public domain.
• MurmurHash3 implementation by Austin Appleby, which is public domain.
• getopt for MSVC, which is public domain.
• SQLite3, which is public domain.

If you are a game publisher and wish to license medusa for commercial usage, please email licensing@mgba.io for more information.