A standalone desktop front end for the same core. It runs on macOS, Windows and Linux with no RetroArch installed, and it drives the core through the same retro_* API RetroArch uses, so every core option and save state behaves the same in both. New in v3.9.0; it carries the core’s version number.

Screenshot gallery

Click a picture to enlarge it (Esc closes, arrow keys move on). All real captures of the app with a demo library: no personal data, no signed-in account.

Library & artwork

Your games on the home screen, in Cartridges, Jaguar CD and BIOS & system tabs, with search, filters and a size slider.
Identified by CRC32 against the libretro database (No-Intro, Redump); box art comes from libretro-thumbnails on demand and is cached.
Favorites and Recently played, as tabs, strips or both; a Save states tab lists every game with states.
Jaguar CD discs get box art too, from the project’s own thumbnail mirror (libretro-thumbnails has none for the system); a disc without art gets a readable title card, or your own PNG.

The app home screen on the Cartridges tab: a Favorites strip of five games and a Recently played strip of six above a grid of Atari Jaguar box art tiles with titles. — **Home screen** Cartridges tab: Favorites and Recently played strips above the box art grid.

The Jaguar CD tab: a grid of thirteen disc tiles with Jaguar CD box art (Baldies, Battle Morph, Blue Lightning, BrainDead 13, Dragon's Lair, Highlander, Hover Strike, Iron Soldier 2, Myst, Primal Rage, Space Ace, Vid Grid, World Tour Racing), each with a CD badge and the game name. — **Jaguar CD** Thirteen discs with box art from the project’s thumbnail mirror; set your own cover with a PNG for any that lack it.

The Save states tab: games grouped by title, each with thumbnails of its Auto-save and numbered slots, timestamps and Delete buttons. — **Save states tab** Every game with states, with the screenshot saved with each; click one to start from it.

The BIOS and system tab: console boot ROM and Jaguar CD BIOS pickers, HLE or real BIOS choice, Boot buttons, an Import button and one BIOS file found. — **BIOS and system** Choose the boot ROM or CD BIOS the core uses, or boot one on its own.

Playing

Save states with thumbnails (F5, F6, F7) and a state manager; Resume where I left off keeps an Auto-save when you close a game.
Per-device and per-game remapping, all 12 keypad keys on a gamepad, the Tempest rotary, mice, light gun and Team Tap.
Cheats from the libretro database and community packs you install from the Cheats window, plus manual codes.
Netplay for the link-cable games (Doom, BattleSphere, AirCars, Ultra Vortek) on a local network; it is not rollback netplay and not for the Internet.
Several windows at once (File > New window) for local multiplayer or netplay tests on one machine.

Community cheat packs. For some cartridges the Cheats window offers a pack of extra cheats under Community cheats: press Install and the app downloads it from this website, checks it and keeps it in your data folder. Every cheat starts off. The pack names its author on screen: the packs are jguffer’s BigPEmu cheat scripts, converted by this project with the author’s permission. Cartridges only; discs have none. Check for updates (or just reopening the window, at most every 6 hours) tells you when a pack changed, and Update or Remove is one click. It is governed by the same Download art and cheat packs switch in the Library as box art, so turning that off stops all of it; installed packs keep working offline. See the privacy policy for what is sent.

A dialog titled Resume where you left off asking whether to resume Alien vs Predator from the saved time, with an Always resume checkbox and Resume and Start fresh buttons over the dimmed game. — **Resume prompt** Next boot offers to continue from the automatic save, or does it at once.

The Save states window for Tempest 2000 listing numbered slots, four with a thumbnail of the saved frame and a timestamp, the rest empty, each with Save and Load buttons. — **State manager** Ten slots with thumbnails and Save and Load buttons (F5, F6, F7).

A translucent panel over the Alien vs Predator title screen listing the Player 1 keyboard bindings: D-pad on the arrow keys, A B C on X Z C, Option on Return, and the keypad on the number row. — **Controls overlay** F3 shows the bindings in effect; it appears by itself when a game starts with a keyboard.

Settings, Input tab, Devices and players: Jaguar port 1 set to Rotary (Tempest), port 2 set to Team Tap, five player slots and tuning sliders for mouse, rotary and stick. — **Input settings** Devices and players: Tempest rotary on port 1, a Team Tap on port 2, and the player slots.

The Cheats window for Tempest 2000: the cheat set, database cheats Infinite Lives (ticked) and Start with 999999 Score, and a manual code entry row. — **Cheats** The libretro cheat database for the running game, a Community cheats section for installable packs, and manual codes.

The Netplay window over Doom: the link device choice between JagLink and Voice Modem, Host a game and Join a game tabs, a Start hosting button and a table of games that use the link. — **Netplay** Host or join link-cable play over a local network.

Skyhammer's cockpit view inside a rusty industrial structure, with green heads-up displays for fire, fuel, shield damage and altitude, a minimap and a Gatling gun gauge. — **A game running** Skyhammer, with the picture scaled to the window.

Blue Lightning running from a Jaguar CD image: a jet fighter seen from behind, flying low over a layer of clouds under a pale blue sky. — **A Jaguar CD game** Blue Lightning, started from its .cue file, in flight. No BIOS file needed.

Look & feel

Dark, light or your own themes: the Theme picker in Settings > Interface follows the OS or takes a fixed choice, and the theme editor changes eleven colours, the rounding and the spacing live, with a contrast check, and exports and imports theme files.
Any font installed on your computer for the interface, at 11 to 24 pt: every name in the list is drawn in its own typeface, starred fonts stay at the top, and the debug windows have a monospace font of their own.
RetroArch .slangp shader presets through librashader, with the slang-shaders CRT, scanline and interpolation families bundled; aspect fit, integer scaling or stretch.
Native menus: the macOS menu bar and Dock menu, the Windows dark title bar and Jump List, Linux desktop actions; windows can be dragged out of the main window.

The same saved moment, plain and through the bundled crt-gdv-mini-ultra-trinitron preset (an aperture-grille, Sony Trinitron style look). Both use aspect fit: the picture keeps its 4:3 shape and is letterboxed, never stretched.

The Alien vs Predator main menu (Select Character, Restore Game, High Scores, Credits) drawn sharp at its 4:3 shape inside the app window, with black bars at the sides.

The same Alien vs Predator menu through the crt-gdv-mini-ultra-trinitron shader preset, in the same 4:3 frame, with vertical aperture-grille phosphor stripes, faint scanlines and a soft glow like a Sony Trinitron tube.

Settings, Video tab: integer scaling, smooth filter, stretch, aspect ratio, VSync and fullscreen options, and a Shader section with the crt-gdv-mini-ultra-trinitron preset selected above a list of 500 built-in presets. — **Video settings** Integer scaling, filter, aspect ratio and the shader list with its CRT presets.

The Rayman title screen through the crt-lottes shader preset: a slightly curved screen with a dark rounded border, visible scanlines and a soft glow around the bright lettering. — **Another preset** crt-lottes on the Rayman title: curved glass, scanlines and glow. Presets are one click in Settings > Video.

Settings, Interface tab: Show frame rate and controls overlay options, an Appearance section with a Dark theme choice and a Customize button, and a Font section with a searchable typeface list and a size slider. — **Interface settings** Overlays, Theme and Font in one tab: frame rate, controls overlay, typeface and size.

The Font section of Settings, Interface, set to Inter: a searchable list with Built-in, Favorites and Recent groups and every name drawn in its own typeface, a preview of mixed text, and a Debugger font list with a hex and disassembly sample beside each monospace font. — **Font picker** Installed fonts drawn in their own typeface, favorites and recents, and a debugger font with samples.

The home screen library with the built-in Light theme: a pale grey background, light buttons and tabs, and the same Favorites, Recently played and box art grid. — **Light theme** The same library in the built-in Light theme.

The home screen library in a custom dark theme named Jaguar Red: near-black red background, dark red tiles and tabs, and red buttons and highlights. — **Custom theme** Jaguar Red, a dark custom theme with a red accent and rounder corners.

The home screen library in a custom light theme named Paper: cream background, sand coloured tiles, green tabs and buttons and larger rounding. — **Another theme** Paper, a warm light theme with a green accent and extra spacing.

The Theme editor window over the library in the Jaguar Red theme: a name field, hex colour boxes with swatches for home background, window, input fields, text, accent and the status colours, rounding and spacing sliders, a contrast check message and Save, Duplicate, Delete, Export and Import buttons. — **Theme editor** Eleven colours, rounding and spacing change the whole app live; contrast is checked.

Shaders are optional: if a preset does not compile or librashader is missing, the app draws the plain picture and says why. Point Preset folder at a full slang-shaders checkout for the rest, and preset parameters get sliders. Platform notes: every package bundles the librashader runtime: macOS (Apple Silicon and Intel), Windows, the AppImage, the .deb and the Flatpak (details in the packaging notes).

RetroAchievements & Discord

RetroAchievements: sign in from the Achievements menu; the login token lives in the system keychain, never your password. Softcore by default, optional hardcore (no loading states, no cheats).
The Achievements window has your profile, the game’s list with badges, and a Jaguar games tab with your progress and a Play button for games in your library. Cartridges and .cue discs are identified.
Discord Rich Presence (Settings > Discord): shows the game you are playing, its box art, how long and your achievement progress, with a Get Virtual Jaguar button for other people. On by default, needs Discord running, and you can turn it off.
See the privacy policy and terms for what the app sends where (box art and database downloads, RetroAchievements, Discord).

The Sign in to RetroAchievements window over a running game: a note that the password is sent once and wiped, User name and Password fields, and Sign in and Cancel buttons. — **Sign in** The password goes to retroachievements.org once; only the login token is kept, in the system keychain.

The Achievements window on the This game tab for Ultra Vortek over its title screen: the game icon, a progress bar at 61 percent, 11 of 18 achievements and 145 of 215 points, then a list with grey locked badges followed by coloured unlocked badges, each with a title, description, points, how many players earned it and the unlock date. — **This game** Badge art, points, rarity and unlock dates, with filters, sorting and search.

The Achievements window on the Jaguar games tab filtered to In my library: nine games, cartridges and Jaguar CD discs, each with its icon, achievement count, points, a progress bar and a Play button; the running game shows Playing. — **Jaguar games** Every Jaguar and Jaguar CD game with achievements, your progress, and Play for those in your library.

Settings, Discord tab: Show what I'm playing on Discord, Show game artwork and Show buttons options, a status line and a note listing exactly what is shared, and a collapsed Application ID section. — **Discord** What is shared with Discord, and switches for artwork and buttons. Off here.

The RetroAchievements pictures use the app’s built-in mock server, so no real account or sign-in was involved. It answers with the real, public achievement list and artwork of the games shown (from retroachievements.org and its image host); the account, progress and unlock dates are made up. Discord was off for its picture.

Developer tools

A Tools menu for the game that is running: memory viewer and editor, palette (CLUT) editor, cheat scanner, Object Processor list, blitter log, texture browser and audio scope.
A CPU debugger with 68000, GPU and DSP tabs: registers, disassembly, breakpoints, step, step over and run to cursor (F9 breaks, F10 steps).
Writes go to RAM freely; hardware registers need a tick-box, and everything is off under RetroAchievements hardcore. RetroArch is unaffected.
gdb: the core also speaks the GDB remote protocol, so a real gdb can set breakpoints, read memory and registers and step the 68000 (the GPU and DSP via monitor commands). Off by default, loopback only. LLDB can attach but cannot debug the 68000. The GDB remote debugging guide has the rest.

$ virtualjaguar --option virtualjaguar_gdb_stub=enabled --option virtualjaguar_gdb_wait=enabled game.jag
$ gdb -ex 'set endian big' -ex 'target remote 127.0.0.1:2345'
(gdb) x/3i $pc
(gdb) stepi

The first option turns the stub on (Settings, search “gdb”, does the same; reopen the game); the second halts the 68000 before its first instruction so gdb attaches at the start. Use a gdb with m68k support (Homebrew gdb; gdb-multiarch on Debian and Ubuntu); set endian big is needed, or every word reads byte-swapped.

The CPU debugger window halted on a 68000 instruction: data and address registers, status register flags, a disassembly with the current line marked, and a breakpoints list, with a HALTED bar at the top of the window. — **CPU debugger** 68000, GPU and DSP tabs: registers, disassembly, breakpoints, step. Shown halted.

The Memory window over Alien vs Predator: a region picker, 8, 16 or 32 bit view, a go-to box and a hex dump of main RAM with an ASCII column. — **Memory viewer** Hex view and editor over RAM and the hardware registers.

The Object list window: the decoded Object Processor display list with branch, stop and bitmap objects, their addresses, sizes and depths, and a preview of the selected bitmap. — **Object list** The whole display list decoded, with a bitmap preview.

The Cheat scanner window: a value size picker, Signed and Aligned options, an initial value mode and Start search, Undo and New search buttons. — **Cheat scanner** Search RAM for a changing value; finds become ordinary cheats.

The Palette (CLUT) window over Alien vs Predator: a CRY or RGB16 choice and a 16 by 16 grid of colour swatches spanning the hue and brightness range. — **Palette (CLUT)** The 256-entry colour lookup table as CRY or RGB16; click a swatch to edit it.

The Blitter log window: counters for shown, seen and missed launches and a table of blits with frame, command flags, A1 and A2 addresses, size and engine. — **Blitter log** Every blit the game launches, newest first, with a filter and a full decode of each.

The Textures window with Dump textures while playing ticked: a count of 856 captured tiles for Alien vs Predator, filter and size controls, and a grid of tile thumbnails. — **Texture browser** Dump the tiles a game blits, then export them or swap in your own art.

The Audio scope window: left and right waveform plots over 1024 samples and level meters with peak markers near minus 13 decibels. — **Audio scope** What the core sends to the audio device: left and right waveforms and peak meters.

The Virtual Jaguar app

About the packages