# RetroArch

Note: RetroArch is not affiliated with Arch Linux.

RetroArch is a modular, command-line driven, multi-system emulator that is designed to be fast, lightweight, and portable. Some of its features can be found on few other emulators, such as real-time rewinding and game-aware shading based on the libretro API.

## Installation

Install the retroarch package or alternatively retroarch-gitAUR for the development version.

## Usage

RetroArch uses separate libraries, called "emulator cores" or "emulator implementations", available from both Community and the Libretro GitHub repository.

Each libretro core package will install a library to `/usr/lib/libretro`. The syntax to choose one when executing retroarch is:

    $ retroarch -L /usr/lib/libretro/libretro-core.so path/to/rom

A default emulation core can be defined in the configuration, obviating the need to specify it on every run.

    /etc/retroarch.cfg or ~/.config/retroarch/retroarch.cfg

    libretro_path = "/usr/lib/libretro/libretro-core.so"

## Configuration

RetroArch provides a very well commented skeleton configuration file located at `/etc/retroarch.cfg`.

Copy the skeleton configuration file to your home directory

    $ cp /etc/retroarch.cfg ~/.config/retroarch/retroarch.cfg

It supports split configuration files using the `#include "foo.cfg"` directive within the main configuration file, `retroarch.cfg`. This can be overridden using the `--appendconfig /path/to/config` parameter and is beneficial if different keybinds, video configurations or audio settings are required for the various implementations.

Tip: RetroArch is capable of loading bsnes xml filters and cg shaders that can be defined in `retroarch.cfg` as `video_bsnes_shader` and `video_cg_shader` respectively.
Note: retroarch-gitAUR requires nvidia-cg-toolkit in order to use the cg shaders.
Warning: When using ALSA it is necessary for the `audio_out_rate` to be equal to the system's default output rate, usually 48000.

### Configuring Paths

Some modifications are required to use the correct paths for Arch packages:

    assets_directory = "/usr/share/libretro/assets"
    libretro_info_path = "/usr/share/libretro/info"
    libretro_directory = "/usr/lib/libretro"
    joypad_autoconfig_dir = "/usr/share/libretro/autoconfig"

## Online updater

Recent versions of RetroArch have introduced a built-in menu for updating core files and various assets from the RetroArch Buildbot. It can be accessed from the main menu at "Online Updater"

    Online Updater

    Core Updater
    Update Core Info Files
    Update Assets
    Update Autoconfig Profiles
    Update Cheats
    Update Databases
    Update Overlays
    Update GLSL Shaders

These cores and assets are kept up to date and can be pulled from the updater at any time.

## Troubleshooting

### Input devices do not operate

It is likely to encounter problems if running on a CLI or a display server other than Xorg, because /dev/input nodes are limited to root-only access. This is solved by manually adding a rule in `/etc/udev/rules.d/99-evdev.rules`, with `KERNEL=="event*", NAME="input/%k", MODE="666"` as its contents. Reload udev rules by running:

    # udevadm control --reload-rules

If rebooting the system or replugging the devices are not options, permissions may be forced using:

    # chmod 666 /dev/input/event*

Alternatively, add your user to the "input" group, e.g.

     # usermod -a -G input user

### Poor video performance

If poor video performance is met, RetroArch may be run on a separate thread by setting `video_threaded = true` in `~/.config/retroarch/retroarch.cfg`.

This is, however, a solution that should be not be used if tweaking RetroArch's video resolution/refresh rate fixes the problem, as it makes perfect V-Sync impossible, and slightly increases latency.

### No cores found

By default RetroArch will attempt to find cores in `~/.config/retroarch/cores`. The packages in the official repositories install the cores in `/usr/lib/libretro/` and the core info files in `/usr/share/libretro/info`. The settings can be changed to look in these directories.

## See also

- RetroArch wiki on GitHub
- Documentation for developers

Categories:

- Gaming
- Emulators