About this project

Coffee GB is a desktop emulator for the original Game Boy (GB/DMG) and Game Boy Color (GBC/CGB), built for high compatibility across commercial games, unusual cartridges, homebrew, demos, and diagnostic ROMs. The reusable emulation core is written in Java, while the desktop application and orchestration layer use Kotlin and Java. Key capabilities: - Game Boy and Game Boy Color emulation, including Super Game Boy borders and palettes. - Save states and rewind: ten save slots, named states, previews, autosave/resume, BESS state interchange, screenshots, deterministic input recordings, and battery-backed saves. - Game loading via drag and drop for .gb, .gbc, and .rom files, directly or from ZIP and 7z archives. - Rollback netplay for link-cable games, with synchronized infrared communication through CGB and HuC-1/HuC-3 cartridge hardware. - GBKiss Link support for sending and receiving .gbf files through the cartridge's infrared port. - Customizable display and sound: fullscreen, scaling, rotation, grayscale, color correction, LCD ghosting, audio-device selection, volume and latency controls. - Keyboard and game-controller support, including independent controls for up to four players in compatible Super Game Boy games. - Broad cartridge and accessory support: real-time clocks, rumble, tilt controls, Game Boy Camera, Game Boy Printer, Barcode Boy, Bardigun Reader, Full Changer, Pocket Sonar, Turbo File GB/Advance, Singer/Jaguar sewing machines, and Datel Action Replay pass-through. - Game Genie and GameShark cheats with a bundled searchable libretro cheat database. Compatibility is a defining feature. The project reports 5,858 automated verdicts from 17 suite families, all passing, and a maximum score in GBEmulatorShootout. Exact-reference image suites such as Acid2, CGB-ACID-HELL, Strikethrough, CasualPokePlayer tests, and Mealybug Tearoom tests are described as pixel-perfect. Netplay uses a direct, unencrypted TCP connection, so it should only be used with trusted people and networks. Pause, save states, and rewind are unavailable during netplay. ROM files are not included. The project is available under the MIT License.