warp-rs

Fly a starship through the universe at warp, in your terminal.

Running it

cargo install --path .         # then just `warp`
cargo run --release            # or fly it from the clone
cargo run --release -- --demo  # autopilot, 45 seconds, no keyboard needed

It needs a terminal to fly in and says so if it has not got one; --headless is the way to send frames somewhere else.

Controls

SPACE	Engage or drop out of warp.
↑ ↓	Throttle.
C	Change camera: the cockpit, or a chase view from outside.
+ -	A fainter or a brighter sky, half a magnitude at a time.
WASD	Pitch and yaw from the cockpit; walk the camera round the ship from outside. I and K pitch too.
QE	Roll the ship, or roll the camera.
[ ]	Push the outside camera in or out. So does the wheel.
M	The ship picker, from outside.
P R	Pause, and put the view and the throttle back where the flags asked for.
ESC	Quit. So does Ctrl-C.

warp --help prints the same table, which is worth knowing on a terminal narrower than about ninety columns: the hint line along the bottom of the panel sheds detail to fit, and on eighty columns it names only the first few.

Options

Flag
--demo [SECS]	Fly on autopilot, then exit. Defaults to 45 seconds.
--screensaver	Fly on autopilot forever; any key quits. For tmux's lock-command.
--magnitude M	How faint a star the sky holds. Default 6.0; each magnitude is about four times as many. Low enough is an empty sky.
--fps N	Frame rate cap, while nothing is being typed. Default 60.
--color truecolor|256|ascii	Colour depth. 24-bit by default.
--engage	Start with the drive already lit.
--view cockpit|side	Which camera to start behind. C cycles them.
--orbit AZ,EL[,ROLL]	Where to park the outside camera, in degrees.
--ship NAME	Which ship to fly, and only visible from outside: enterprise (the default) or normandy.
--throttle 0..1	Starting throttle.
--exposure N	Tonemap exposure. Higher is brighter.
--fade SECS	How long a camera change takes, dipping through black. The sky arrives over the tail of one at the start of a run. Default 0.6; 0 cuts straight.
--aa N	Samples per subpixel, per axis, for the hull's outline. Default 3; 1 is a hard edge.
--seed N	Fix the sky. Omit for a different one each run.
--size COLSxROWS	Override the terminal size.
--headless --frames N	Print frames to stdout instead of taking over the terminal. In this mode --fps is the simulation timestep rather than a cap, so it changes the flight.

The autopilot works the throttle and the camera, so --screensaver --view side walks the shot round the hull rather than parking it, and no two runs up to warp are flown quite alike. --orbit still says where the shot starts; the camera wanders out from there. It does not steer: a flight nobody is flying holds the heading it was given and runs dead straight, and what moves is the camera and the drive. Neither --demo nor --screensaver draws the instrument panel, since there is nobody at the controls for it to be reporting to.

The sky

Stars are where their own photometry puts them. A star is drawn from the spectral census, given an absolute magnitude, and placed at the distance that makes it look as bright as it does — so the near ones are faint red dwarfs a few light years off and the bright ones are giants a thousand light years away, which is the arrangement the real sky is in.

Two things follow, and they are the reason for it. At impulse the sky does not move: 0.9 c against a nearest star four light years off is a hundredth of a subpixel a second, so the stars sit still and only the twinkle moves. And at warp — 2000 c is five and a half light years a second — the near sky tears past a far one that barely shifts, which is depth rather than speed and is the thing a fixed backdrop cannot show.

--magnitude is the knob, and it is the one astronomers use: a sky is described by how faint a star you can pick out of it, not by how many there are. + and - move it half a magnitude at a time. How many land on screen is then the field of view's business, so a wider terminal shows more sky rather than the same sky stretched.

Terminals

The renderer targets 24-bit colour and draws with the upper half block, ▀, so each cell is two roughly square pixels. It opens in 24-bit everywhere and does not inspect COLORTERM or TERM to decide: the narrower modes are asked for rather than fallen into. --color 256 snaps the frame to the xterm palette for a terminal that cannot read a 24-bit sequence, and --color ascii drops colour altogether for a brightness ramp. --color ascii sends no escape codes beyond the cursor moves the grid is painted with, so piped rather than displayed it is plain text and nothing else.

License

MIT. See LICENSE.