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.\" Man page for roids, by Terry Weissman.
.TH roids 1 "10 March 1989"
.SH NAME
\fIroids\fR \- Dodge and shoot the flying rocks.
.SH SYNOPSIS
.B roids
[-display display:number]
.SH DESCRIPTION
.I roids
is an implementation of the old Atari Asteroids game, on top of the
X11 window system.  Be warned that it only works on
.B very
fast workstations.

.SH PLAYING ROIDS
Initially, you will be presented with a black window.  Nothing will
happen until you give input focus to that window.  (How you do this
depends on your window manager; in most of them, you just move the
mouse into the
.I roids
window.  In some, you'll have to click the mouse as well.)

Once you get things going, you'll find yourself in control of a small
triangular ship, dodging big rocks.  Your controls are:

.PP
.TP 8
.B z
Rotate the ship to the left.  It will continue rotating as long as the
key stays depressed.
.PP
.TP 8
.B x
Rotate the ship to the right.  It will continue rotating as long as the
key stays depressed.
.PP
.TP 8
.B ,
Apply thrust.  Thrusting will continue as long as the key remains depressed.
.PP
.TP 8
.B .
Fire a bullet.  You may have up to four bullets flying at once.
.PP
.TP 8
.B Q
Abort the game.  This must be entered as a capital Q (the shift key
must be down).

If you prefer, you may control your ship with the mouse.  The controls
here are:

.PP
.TP 8
.B Left
Rotate the ship to point towards the mouse arrow.
.PP
.TP 8
.B Middle
Apply thrust.
.PP
.TP 8
.B Right
Fire a bullet.


.SH SCORING

Big rocks are worth 50 points.  Medium rocks are worth 100 points.
Small rocks are worth 200 points.

You have three ships.  You get a free ship every 10,000 points.




.SH CUSTOMIZING COLORS

As with all standard X applications,
.I roids
may be customized through entries in the resource manager.  This
almost always means editing your .Xdefaults file.  [Note: the entry names
must be entered in either all lower-case, or in the exact
case shown below.]

.PP
.TP 8
.B ShipColor
The color to paint your ship.  (Default is green.)
.PP
.TP 8
.B RockColor
The color to paint rocks.  (Default is gold.)
.PP
.TP 8
.B ShotColor
The color to paint shots.  (Default is red.)
.PP
.TP 8
.B ScoreColor
The color to paint the score.  (Default is violetred.)


.SH CUSTOMIZING MOUSE AND KEYBOARD

If you wish to set up your own interpretation of the mouse and
keyboard, the following actions are provided:

.PP
.TP 8
.B grab-focus
Grab the input focus.  This is only useful if bound to a mouse action.
.PP
.TP 8
.B rotate-left
Start rotating the ship to the left.
.PP
.TP 8
.B rotate-right
Start rotating the ship to the right.
.PP
.TP 8
.B rotate-off
Stop any rotation.
.PP
.TP 8
.B thrust-on
Begin thrusting.
.PP
.TP 8
.B thrust-off
Stop thrusting.
.PP
.TP 8
.B rotate-to-point
Begin rotating to point to where the mouse is pointing.  This may only be
bound to a mouse-down action.
.PP
.TP 8
.B stop-rotate
Cancel a currently executing rotate-to-point.  This may only be bound
to a mouse-up action.
.PP
.TP 8
.B rotate-moved
Change the point to rotate to.  This may only be bound to a
mouse-motion action.
.PP
.TP 8
.B fire
Fire a shot.
.PP
.TP 8
.B quit
Quit the game.
.PP

It is beyond the scope of this document to describe how to use these
actions in your .Xdefaults file to change the keyboard and mouse
interpretation.  As an example, though, here is what you would use to
get the default behavior:

Roids*Roids*translation:	\\n\\
     <Btn1Down>:	grab-focus() rotate-to-point()\\n\\
     Button1<PtrMoved>:	rotate-moved()\\n\\
     <Btn1Up>:		stop-rotate()\\n\\
     <Btn2Down>:	thrust-on()\\n\\
     <Btn2Up>:		thrust-off()\\n\\
     <Btn3Down>:	fire()\\n\\
     <KeyDown>z:	rotate-left()\\n\\
     <KeyUp>z:		rotate-off()\\n\\
     <KeyDown>x:	rotate-right()\\n\\
     <KeyUp>x:		rotate-off()\\n\\
     <KeyDown>\\\\,:	thrust-on()\\n\\
     <KeyUp>\\\\,:	thrust-off()\\n\\
     <KeyDown>.:	fire()\\n\\
     Shift<KeyDown>q:	quit()


.SH MOTIVATION

I've always wanted to write one of these games.  Unfortunately, I
don't enjoy optimizing code to be very fast, and that's what has
always been necessary for good arcade games on every machine I've
used.

Until I got my DECstation 3100.  This machine is fast enough that I
didn't have to write efficient code.
.I Roids
does stupid things like repainting the ships location 100 times a second, and
it doesn't matter.

Thus, I have written a game that (probably unnecessarily) requires a
very fast workstation.  Please don't interpret this as snobbishness on
my part ("your workstation isn't as fast as mine so you can't play my
game, nyah nyah"); it is just laziness.

.SH NOTES

There are lots more resources.  The ones above are the only ones I
want documented; the rest change the behavior of the game.  The
curious should look at the source.

The mouse controls are, in my opinion, useless.  I'd be very
interested if anyone actually likes them.  (I implemented them for a
friend who refuses to use his keyboard to play games.)

Collision detection is very good.  I actually check to see if things
touch; I refused to use the standard method of just seeing if the centers
of objects are close.  Of course, this is a large part of why
.I roids
needs a fast workstation.

.I Roids 
works only on very fast workstations.  Don't try and play it over a
network; it won't work.

.SH BUGS

The rocks look really stupid.  Anyone have some good rock designs?

You shouldn't have to re-run the program to play another game.

There should be high-score mechanisms.

Doesn't handle different visuals like a good X client should.  In
particular, if you play this on a display with a StaticGrey visual,
you will probably not be able to see anything.

The default colors don't show up well on all displays.

No enemy ships.  In a way, this is a feature; I always despised the
fact that people could get lots of points in the original Asteroids by
leaving one tiny little rock and blasting all the enemy ships.

The code really could be a lot more efficient, and therefore work well
over a larger variety of machines.


.SH AUTHOR

Terry Weissman
.br
Western Software Laboratory
.br
Digital Equipment Corporation
.br
weissman@wsl.dec.com
DataMuseum.dk

DKUUG/EUUG Conference tapes

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