Swift Retro

This repository contains a Swift API for Gym Retro.

Installation

Prerequisites

Retro depends on the native Gym Retro library and on GLFW which is used for rendering. The native Gym Retro library can be installed by executing the following commands in a temporary working directory:

git clone git@github.com:eaplatanios/retro.git
cd retro
git checkout c-api
cmake . -G 'Unix Makefiles' -DBUILD_PYTHON=OFF -DBUILD_C=ON
make -j8 retro-c
make install

GLFW can be installed by executing the following commands:

# For MacOS:
brew install --HEAD git glfw3

# For Linux:
sudo apt install libglfw3-dev libglfw3

After having installed these libraries you should be able to use this library.

NOTE: The Swift Package Manager uses pkg-config to locate the installed libraries and so you need to make sure that pkg-config is configured correctly. That may require you to set the PKG_CONFIG_PATH environment variable correctly.

NOTE: If the rendered image does not update according to the specified frames per second value and you are using MacOS 10.14, you should update to 10.14.4 because there is a bug in previous releases of 10.14 which breaks VSync.

Example

WARNING: The below is not relevant anymore. I have been working on a new simpler and more powerful interface and plan to update the examples shown in this file soon.

The following code runs a random policy on the Airstriker-Genesis game for which a ROM is provided by Gym Retro.

let retroURL = URL(fileURLWithPath: "/Users/eaplatanios/Development/GitHub/retro-swift/retro")
let config = try! Emulator.Config(
  coreInformationLookupPath: retroURL.appendingPathComponent("cores"),
  coreLookupPathHint: retroURL.appendingPathComponent("retro/cores"),
  gameDataLookupPathHint: retroURL.appendingPathComponent("retro/data"))

// We only use the OpenGL-based renderer if the GLFW flag is enabled.
#if GLFW
var renderer = try! SingleImageRenderer(initialMaxWidth: 800)
#else
var renderer = ShapedArrayPrinter<UInt8>(maxEntries: 10)
#endif

let game = emulatorConfig.game(called: "Airstriker-Genesis")!
let emulator = try! Emulator(for: game, configuredAs: emulatorConfig)
var environment = try! Environment(using: emulator, actionsType: FilteredActions())
try! environment.render(using: &renderer)
for _ in 0..<1000000 {
  let action = environment.sampleAction()
  let result = environment.step(taking: action)
  try! environment.render(using: &renderer)
  if result.finished {
    environment.reset()
  }
}