ExPilot

A multiplayer XPilot in the terminal, in the browser and on the desktop, on Cauldron. Classic block maps, newtonian ships, thrust and shields and fuel, cannons, wormholes, robots, items — mines, missiles, lasers, cloaks, ECM, transporters, tractor beams, deflectors, phasing, hyperjumps and the rest — teams, targets, capture the flag, races, a radar, and music that follows the fight.

A tour of the game, with its music, is on YouTube.

mix ex_pilot.play                       # this terminal, this machine's speaker
mix ex_pilot.serve --port 2222          # over ssh and in the browser, one process
mix ex_pilot.maps                       # fetch the 132 classic maps into priv/maps

The lobby

Every map under priv/maps is an arena in the lobby — Dogfight is bundled, the rest come from mix ex_pilot.maps — with its size and robot count beside its name (an arena with none is practice); robots never take every base, one is always left for you. The list scrolls (PgUp/PgDn, Home/End, the wheel); a click chooses a row and a second click joins it, Enter joins, w watches, t picks a team. An arena's world and robots start when someone joins it and stop again after two minutes with nobody in it. h opens the guide: everything you can meet in an arena, drawn beside a line on what it does and the key that uses it.

Flying

The defaults are WASD with the pointer steering: a/d turn (and the ship follows the mouse until a turn key is pressed), w or the right mouse button thrust, space or the left mouse button fire, s or left shift shield — a shielded ship shows a ring. Settings

(s on the title or in the lobby, Tab in the arena) offers arrows and vi presets, rebinding, pointer steering, effects and music levels, display and frame rate.

A game controller plays wherever the program runs on your own machine — the terminal client, the browser, the phone with a pad paired — in the Xbox layout whatever the hardware: the left stick aims — the ship turns to the way you push it — the d-pad turns left and right, the right trigger thrusts as far as you pull it (d-pad up in full), B or the right bumper fires, A or the left trigger shields,

X fires a missile, Y drops a mine, the left bumper fires the laser, pressing the sticks picks the next missile and cloaks, d-pad down is the emergency shield, Back the emergency thrust, and A or Start picks the next ship when watching. The web settings page rebinds any of it — click an action's row and press the control, or write the controls out — keeps the bindings in your account for every client, and resets to the default; "the aim stick also thrusts when pushed past its ring" makes one stick fly the ship, thrust growing with the push, as the phone's thumbstick does. A pad steering the ship lets go of the mouse's aim until the mouse moves. Over ssh the controller stays on your side of the connection, so only the keys reach the game.

A ship sits on its base until it thrusts, and launches away from the wall its base is on. Held turn keys take over from the pointer until it moves again. A ship that has just appeared — joined, respawned or at a new round — cannot be hit for three seconds and shows its shield meanwhile. A tank that has been empty for ten seconds loses the ship, on the base or off it. Ships that fly into each other crash unless shielded; shielded ships bounce apart. Walls bounce a ship that touches them slowly or with its shield up — an unshielded bounce costs fuel — and crash one that hits them faster.

The hud is a column down the left as in XPilot: the radar on top — you in yellow, teammates blue, enemies red, bases grey — then you, your items and the scores, with the arena's messages along the bottom; it counts the enemies still in the round. t talks to the arena; ? shows the keys (tap to keep, hold to peek); +/- (the wheel, a pinch) zoom out to the whole arena and back and 0 puts it back; Esc or q goes back to the lobby, ^Q quits.

Rounds

With limited lives, a ship out of lives watches the nearest ship still flying — Enter steps to the next one, for a spectator too — and the round ends as in XPilot when one ship (one team) is left standing among two or more (alone in an arena you fly for practice; nothing is won or lost): it is told it won, everyone is back on their bases four seconds later, and for you it is a summary — Victory or Defeat with the standings. Enter after a Victory joins the next arena in the list, after a Defeat the same one again; Esc returns to the lobby.

Robots

Robots launch off their bases, hunt the nearest enemy anywhere in the arena along the clearest heading toward it, brake off walls, fire within reach and go for a fuel station when the tank runs low. Each is seated with a skill of its own, drawn at random: the sharp ones aim tight, fire from far and react in three frames; the dull ones spray, wait for a closer shot, hesitate on the trigger and think three times slower. A player who finds every base taken gets a robot's, and the robot comes back when there is room again.

Items

Items appear on the map and are picked up by flying over them; the hud lists what you carry. 1 drops a mine, 2 fires a missile (n picks torpedo, smart or heat), 3 fires the laser, c cloaks, e jams, r steals with the transporter, g/b pull and push with the tractor beam, x deflects, p phases through walls, u hyperjumps, [/] emergency shield and thrust, o autopilot, v drops the ball.

Teams, targets, balls and races

On a team map teammates' shots pass through each other, the ! targets take three hits, and carrying the other team's ball from its * treasure into your own scores: the ball hangs on a string that tugs the ship and snaps when overstretched, and falls, drifts and bounces on its own when loose. A race map runs laps over the A–Z checkpoints. The music follows the kind of arena — a dogfight, capture the flag, a team battle and a race each have their own pieces.

Duels

From the browser's lobby, challenge a pilot on an arena, first to a number of kills: a private arena appears in every lobby — the two of you fly it, anyone can watch — and closes when it is won. Watching, the arrows or a drag pan the view, the wheel and a pinch zoom about the pointer, and 0 recentres it: watch a duel from above, or close in on it.

Leaders

Every round's result — kills, deaths, whether it was won, the best streak of kills without dying, the longest contact (seconds alive with an enemy within thirty tiles) — goes to the boards: today / this week / all time, by kills, kills a death, rounds won, streak, contact or laps, over every arena or one. /leaders in the browser, l in the terminal and on the desktop. Robots' results are not kept.

In the browser

The server serves the game to browsers at http://host:2280/ (--http N picks the port, --http 0 turns it off). Log in or make an account — the same accounts as ssh — pick an arena, and play on a canvas beside ssh players in the same world: a/d or the arrows turn, s/↑ or the right mouse button thrust, space or the left button fire, w/shift shield, the pointer steers, Enter steps through the ships when you are watching, m shows the frames a second, and ♪ in the bar switches the music off and on. Sound plays in the page, nothing to set up. Every arena card offers a team or a plain join and watch; the guide page shows everything in the game with its sprite.

On a phone or a tablet the arena is the game alone — no bars, nothing to scroll: a thumbstick steers and, pushed far, thrusts (it is analog: thrust grows with the push from its ring to its rim); buttons fire, shield, fire a missile and thrust; fuel and score ride over the world, ≡ opens the rest of the hud over it, ⤢ goes full screen and ✕ leaves. The settings page keeps the phone's controls in your account: which hand the stick is under (the buttons go under the other), and tilt to steer — tilting the phone turns the ship, the stick then thrusts (a touch for a little, a push for more) and steers only when pushed past its ring, so a hand on each. iOS asks once for motion access when you switch tilt on; the phone's music level is on the same page. The pages have a tab bar along the bottom; "Add to Home Screen" opens the game without the browser's bars. ?touch=1 or ?touch=0 on any address forces the phone layout either way and is remembered.

On the desktop

mix ex_pilot.desktop opens a window played with the keys like the ssh client: Enter from the title, pick where the arenas are — a server by its URL (log in or register), a node, or this app — pick an arena, Enter joins, w watches, t picks a team; in the arena Esc or q returns to the lobby. h on the title is the serve screen: ssh and web ports, interfaces, accounts file and robots, Enter starts or stops the server. --url, --name, --node, --cookie fill the fields in. Sound plays through your speaker. s on the title or in the lobby, Tab in the arena, opens the settings: sound, the pointer steering, your ship (the presets, kept in your shipshape file for the arenas this program runs — a server's arenas fly what your account there says), with the keys listed beside them.

In a terminal, with everything

mix ex_pilot.terminal                       # play here, connect elsewhere, host, leaders
mix ex_pilot.terminal --name alice --url http://arcade:2280

The terminal has the desktop's flow: Enter plays the arenas this program carries, c connects — to a server by URL or to a node — h hosts a server from inside (ssh, web, the node name and cookie others need, calling on the local network so their connect screens list it), l shows the leaders. mix ex_pilot.play is the same client with its own title and only the local arenas; mix ex_pilot.serve is the headless server.

Playing over ssh

ssh -p 2222 new@host                                       # register: pick a name and password, then play
ssh -p 2222 alice@host                                     # play
ssh -p 2222 -R 24713:127.0.0.1:4713 alice@host             # play with sound

The game synthesises its sound on the server and sends it back down the reverse tunnel to whatever listens on your machine's port 4713 — ffplay on any OS with ffmpeg (brew install ffmpeg, winget install ffmpeg, apt install ffmpeg):

while :; do ffplay -nodisp -autoexit -fflags nobuffer -analyzeduration 0 -probesize 32 -f s16le -ar 44100 -ch_layout stereo -i "tcp://127.0.0.1:4713?listen"; done

ffplay ends when a session's connection closes, so the loop puts a fresh listener up for the next one; on Windows the loop is for /L %i in (1,0,2) do ffplay … in cmd and while ($true) { ffplay … } in PowerShell. Every account has its own port on the server (24713 for the first registered, 24714 for the next…); the title screen's "No sound?" (n, or a click) shows the lines with your own port, and Esc closes it. Start the listener before or after the game. Someone with Elixir and this project on their machine can run mix ex_pilot.listen instead of ffplay; sox and pacat work too (sox -t raw -r 44100 -e signed -b 16 -c 2 - -d < <(nc -l 4713), pacat --raw --format=s16le --rate=44100 --channels=2 < <(nc -l 4713)).

The display setting picks pixels where the terminal has them, braille, or glyphs, and the frame rate (auto is the terminal's best: 15 on iTerm2 and sixel terminals, 30 elsewhere). Your own shipshape is the one your account keeps — the web settings page offers a few by name (classic, dart, wedge, wide, saucer), drawn as you pick, or takes one written in XPilot's notation, (SH: 15,0 -8,8 -8,-8)(EN: -8,0)(MG: 15,0) — and every client flies it; without one, the server reads $XDG_CONFIG_HOME/expilot/<player>.shipshape where the world runs.

When your ship is destroyed, every client says what did it — "shot by alice", "hit a wall", "hit bob's mine", "collided with carol", "ran out of fuel" — over the world from the explosion until two seconds after you are back on your base.

Your name, and the name others see

Nobody sees your account name but you and an admin. Until you choose otherwise you are seen under an anonymous name of your own — two words and a number, like amber-falcon-27, the same every visit — in the lobby, over your ship, in chat, in duels and on the boards. The web settings page shows you both, alice, seen as amber-falcon-27, and lets you choose an alias instead: one to thirty-two letters, digits, spaces, _ or -, not one another pilot is seen as or named. The boards count by account, so changing it keeps your record. Every client shows you your own name with the one others see after it, so you always know which is which.

Settings

Sound levels, the pointer and keys are kept per kind of client — the terminal, the desktop, a browser, a phone or tablet — in $XDG_CONFIG_HOME/expilot/ and in your account, so what suits a phone does not follow you to the desktop.

Serving

mix ex_pilot.serve --port 2222 --http 2280 --robots 4 runs ssh and the web in one process; --music personal | arena | dynamic | static | off and --sfx off set how much sound the server makes for each session.

mix ex_pilot.admin alice makes an account an admin, and admin joins the pages along the top of the browser: who is logged in, on what kind of client, under which name, in which arena or still in the lobby, and for how long; every arena running and how it is keeping up; every account with the name it is seen under and its record; what happened lately; and the actions — kick a session, stop an idle arena, forget an account's results, grant or revoke admin. Every page in the browser shows how many pilots are logged in; that count opens a panel with the whole list — each by the name they are seen under, where they are, and on what.

TECHNICAL.md has what a session costs, the music policies, load testing, the files on disk and how the code is put together.

License

MIT. The classic maps are community contributions with no stated licence and are fetched rather than shipped; the XPilot source is GPL and was read, not copied.

The scores under priv/scores are LilyPond engravings from the Mutopia Project (mutopiaproject.org) of music long in the public domain: Grieg's In the Hall of the Mountain King (Coyau), Joplin's The Entertainer (Chris Sawer) and Mozart's Rondo alla Turca (Rune Zedeler, Chris Sawer) are released to the public domain; the Prelude to Bizet's Carmen (Alex O'S) is under Creative Commons Attribution-ShareAlike 2.5 and Paganini's Caprice No. 24 (Samuel Rummel) under Creative Commons Attribution-ShareAlike 4.0, so the renders made from those two carry their engravers' names and the same terms. The piano is the Salamander grand, CC BY 3.0 by Alexander Holm; the basses are FreePats' fingered and picked electric bass and Karoryfer Samples' meatbass, all CC0.