# Space Travel

This is a C port of Ken Thompson's
[Space Travel](https://en.wikipedia.org/wiki/Space_Travel_\(video_game\)),
ported from PDP-7 assembly. The original source files are in `src/cmd/st*.s`
in the [pdp7-unix](https://github.com/DoctorWkt/pdp7-unix) repository.

## Install

The SDL2 library is required.

Run `make` to build `st`.

Run `make install` to install to `/usr/local/bin`.

## Controls

| Key | Action       |
|-----|--------------|
| 1   | Quit         |
| 2   | New game     |
| 3   | Thrust down  |
| 4   | Thrust up    |
| 5   | Yaw right    |
| 6   | Yaw left     |
| 7   | Scale up     |
| 8   | Scale down   |

You can also use the arrow keys for yaw and scale.

## Gameplay

> For controls, there were several buttons: jet forward, jet back, turn left,
> turn right; go up scale on the display, go down scale. The acceleration of
> the ship was fixed, but it scaled with the display scale--it was thus fixed
> in terms of pixels/sec/sec. Normally the ship was in the center of the screen
> and always pointed up; the display showed the plan view of the solar system,
> so that the "rotate" controls rotated the solar system around you on the
> display.
>
> No relativity; scale up enough and you travel to Pluto in a few seconds. But
> don't scale up too much, or you might not find the Solar System again without
> restarting.
>
> The object of the game was simply to fly around, get into orbits, land.
> "Land" meant to cross the surface with a small enough speed.
>
> *[Space Travel: Exploring the solar system and the
> PDP-7](https://www.bell-labs.com/usr/dmr/www/spacetravel.html) by Dennis
> Ritchie*

The current dominating attractor, scale, and landing status (L/CL for
landed/crash landed) are displayed at the bottom. The moving dot on the line
below the main view represents the horizontal velocity relative to the current
dominating attractor.

PERMISSION  UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP     NAME
---------- ----------- ------- ------- ------ ---------- ------------ ----------
[unknown]                    0       0 ****** -lhd- 0000 Feb  9 00:24 st-master
[unknown]                   29      29 100.0% -lh0- c39b Feb  9 00:24 st-master.gitignore
[unknown]                  284     502  56.6% -lh5- 1e87 Feb  9 00:24 st-masterMakefile
[unknown]                 1001    1888  53.0% -lh5- f76c Feb  9 00:24 st-masterREADME.md
[unknown]                 1431    7180  19.9% -lh5- 6cf9 Feb  9 00:24 st-masterfont.h
[unknown]                 6282   17362  36.2% -lh5- ff0a Feb  9 00:24 st-masterst.c
[generic]                50919  144480  35.2% -lh5- 56b6 Feb 12 01:33 st-master/st
---------- ----------- ------- ------- ------ ---------- ------------ ----------
 Total         7 files   59946  171441  35.0%            Feb 14 02:32