Sonic Radiant

Sonic Radiant is a portability and modernization fork of jnmartin84/sonic-r, the reverse-engineered C reimplementation of the 1998 Windows release of Sonic R.

The goal is simple: keep the original game logic recognizable and maintainable, while making the project practical to run on modern PCs and additional hardware. Sonic Radiant does not include Sega's retail game data.

Supported targets

Platform	Status	Main backend
Windows	Supported / release build	SDL2 + OpenGL
Linux	Source build	SDL2 + OpenGL
macOS	Source build	SDL2 + OpenGL
Android	Supported / release build (arm64-v8a)	SDL2 + OpenGL ES 1.1
Nintendo Switch	Supported / release build	libnx + EGL/OpenGL
Sega Dreamcast	Supported by the inherited project	KallistiOS

Highlights

• A compact first-run game-data importer instead of a separate themed installer.
• Automatic detection of a valid original Sonic R CUE/BIN image.
• Native Windows CUE picker if automatic detection fails.
• Direct extraction of the retail data track and lossless CD audio import.
• A native Nintendo Switch port with controller, save, audio, rendering, and network integration.
• A native Android port with first-run CUE/BIN import, adaptive multitouch controls, Bluetooth/USB gamepad support, and app-private runtime storage.
• Automatic aspect-ratio rendering from 4:3 through widescreen and ultrawide, with Hor+ gameplay projection and aspect-safe HUD behavior.
• Local multiplayer support where the target supports it.
• LAN, direct-connect, and matchmaker-based networking infrastructure.
• Transactional automatic updates for Windows and Nintendo Switch.
• No retail game assets, authentication credentials, console keys, or private signing material in the repository or release packages.

First launch

You must own and provide your own copy of Sonic R.

Windows

For a fresh installation, download Sonic-Radiant-Windows.zip, extract it to a normal writable folder, and run Sonic-Radiant.exe.

If game data is not already present, Sonic Radiant opens its setup panel inside the game window. It searches for a supported .cue plus its referenced .bin files. If it cannot find them automatically, Windows opens a native file picker.

The source disc image is never modified. Once extraction succeeds, the original CUE/BIN files are no longer required for normal play.

Nintendo Switch

Download Sonic-Radiant-Switch.zip. It contains both the NRO and the optional NSP forwarder. Copy the NRO to exactly:

sdmc:/switch/sonicr/Sonic-Radiant.nro

Launch it through hbmenu or the Sonic Radiant forwarder. If retail data is not present, place the original CUE/BIN files somewhere on the SD card and relaunch; the importer scans the Sonic Radiant directory and common SD-card locations.

The runtime directory intentionally remains sdmc:/switch/sonicr/ so existing saves, game data, diagnostics, and the forwarder continue to work across updates.

Android

Download Sonic-Radiant-Android.apk and install it on a 64-bit ARM Android device. On first launch, select the folder containing your original Sonic R PC CUE/BIN files. Sonic Radiant copies the source image into app-private storage, validates it, and installs the runtime data without modifying the original files.

The Android build includes adaptive on-screen controls. Connecting a supported Bluetooth or USB controller automatically hides and disables the touch overlay.

Automatic updater

Sonic Radiant checks the project's GitHub releases for a newer version. Only non-draft releases are considered. The updater downloads the platform ZIP, verifies the ZIP's SHA-256 digest reported by GitHub, extracts only the running platform binary, validates the ZIP member CRC, and then promotes it transactionally.

Windows update flow

1. Download Sonic-Radiant-Windows.zip to a temporary update archive.
2. Verify the archive SHA-256 and extract Sonic-Radiant.exe to .new.
3. Start a temporary handoff helper copied from the currently running EXE.
4. Exit the current game process.
5. Preserve the previous executable as .old.
6. Promote the verified .new executable.
7. Launch the new build automatically.

Switch update flow

1. Download Sonic-Radiant-Switch.zip while the current NRO remains loaded.
2. Verify the archive SHA-256 and extract Sonic-Radiant.nro to .new.
3. Preserve the previous file as Sonic-Radiant.nro.old.
4. Promote the verified NRO to Sonic-Radiant.nro.
5. Use libnx envSetNextLoad() so hbloader starts the new NRO when the current process exits.

The updater intentionally does not reinstall the NSP. The forwarder always points to the stable sdmc:/switch/sonicr/Sonic-Radiant.nro path, so normal updates only need to replace the NRO.

Both paths are designed to keep or restore the previous binary if an update cannot be promoted safely.

Retail data and saves

Retail Sonic R data is not distributed by this project. The importer creates the expected runtime folders from a copy supplied by the user, including the original data directories and MUSIC/ tracks.

User-created/runtime files stay beside the game data and are not replaced by the updater. Important examples include:

File / folder	Purpose
SAVE/SONICR.SAV	Progress and records
SONICR.INF	Game options
KEYS.BIN	Keyboard bindings
JOYSTICK.INF / SAVE/PADS.CFG	Gamepad configuration
GHOST/	Time Attack ghosts
ONLINE.DAT	Matchmaker sign-in state; private, never publish it

Build from source

Desktop

cd source/sdl
make

For the optimized desktop release build:

cd source/sdl
make release

Nintendo Switch

With devkitPro/devkitA64 and the required Switch libraries installed:

cd source/sdl
make -f Makefile.switch -j8

The result is source/sdl/Sonic-Radiant.nro.

Android

The Android target builds for 64-bit ARM devices. Initialize the submodules, install the Android SDK/NDK versions listed in the Android guide, then build the APK with Gradle:

git submodule update --init --recursive
cd source/android
./gradlew assembleDebug

The APK is written to source/android/app/build/outputs/apk/debug/. For an optimized release package, run ./gradlew assembleRelease. Release APKs must be signed before distribution; see the Android guide for the signing model. Retail game data is never bundled in the APK. On first launch, the Android launcher asks the user to select the folder containing their original CUE/BIN disc image and copies only those source files into app-private storage before the existing importer verifies and extracts them.

More detailed platform documentation:

• Desktop guide
• Android guide
• Nintendo Switch guide
• Dreamcast guide
• Porting guide
• Contributing
• Credits

Repository layout

DATA/                  Sonic Radiant runtime support files
assets/branding/       Application icon / branding
docs/                  Platform and developer documentation
dreamcast/             Dreamcast tooling inherited from the project
source/sdl/            Desktop + Nintendo Switch implementation
source/dc/             Dreamcast implementation
source/android/        Android Gradle project and pinned SDL dependencies

Credits

Sonic Radiant is created and maintained by RadiantDelux.

The original reverse-engineered Sonic R reimplementation was created by jnmartin84 and upstream contributors. Sonic Radiant is built on that work and keeps the upstream repository linked prominently for full historical attribution. See CREDITS.md for additional contributors and dependencies.

License and legal notice

Sonic Radiant is licensed under the GNU Affero General Public License v3.0, matching its upstream foundation. See LICENSE.

Sonic R, Sonic the Hedgehog, Sega, Traveller's Tales, and related trademarks, characters, and retail assets belong to their respective rights holders. Sonic Radiant is an unofficial fan preservation/portability project and is not affiliated with or endorsed by Sega.

This repository and its releases do not contain the original retail game data.