Data

Tools

Indexes

Applications

Experiments

Awesome

An open API service indexing awesome lists of open source software.

https://github.com/ronf/webrtc-spacewar

Browser-based version of classic Spacewar! game which uses WebSockets and WebRTC
https://github.com/ronf/webrtc-spacewar

Last synced: over 1 year ago
JSON representation

Browser-based version of classic Spacewar! game which uses WebSockets and WebRTC

Awesome Lists containing this project

README 

          
WebRTC Spacewar

===============



WebRTC Spacewar is a browser-based recreation of the PDP-1 `Spacewar!`__

game, based on an X11 version I wrote in C back in 1992.



__ https://en.wikipedia.org/wiki/Spacewar!



.. image:: images/spacewar.png

    :target: https://www.timeheart.net/spacewar



Motivation

----------



I created the original version of Spacewar to show how to build a

network-based multi-player game without a server. Clients communicated

directly with one another to share game state. For a two player game,

players specified each other's IP address when starting the game. More

than two players was also supported, by having all the players specify

a common IP multicast group address. Game updates would be sent to that

address and delivered to all other clients which joined that multicast

group. Each client would then independently render a view of all the

ships without the need for a central server. With synchronized clocks,

the clients came very close to all showing the same result within the

limits of the network latency, and any errors due to latency would

automatically be corrected by later game updates.



With this new version of Spacewar, my initial goals were:



  * Learn something about what Javascript is capable of in modern

    web browsers

  * Learn how WebSockets work and what they're capable of



Due to web browser security restrictions, a true peer-to-peer version

of the game in a browser with no server at all wasn't possible, but I

wanted to keep all the actual game logic completely within the browser,

implementing only a very basic WebSocket "relay" that replaced the

IP multicast communication in my original version. More details on

this WebSocket relay can be found `here`__.



__ ws-relay.rst



Once I had the WebSocket version of the game running, I decided it

would also be interesting to use this project as an opportunity to

learn more about what WebRTC was capable of, getting closer to the

true peer-to-peer nature of my original implementation by using

WebRTC data channels to send game state directly between clients.

Unfortunately, WebRTC doesn't support IP multicast, so that had to

be simulated by building a mesh of unicast connections between the

clients. Also, to set up WebRTC, a signaling channel had to be

provided, but the WebSocket relay I had already written turned out

to be perfect for that.



Game Basics

-----------



The basic game controls let you turn your ship, thrust in whatever

direction you are facing, and fire missiles in that direction. You can

fire two missiles per second, and they'll deactivate after five seconds,

or sooner if they hit something.



Be sure to take into account the sun's gravity when maneuvering and

aiming your missiles. If you like, you can slingshot your ship or your

missiles around the sun, but don't get too close or you'll be sucked

in, and be careful not to shoot yourself!



If a ship collides with the sun, another ship, or a missile, it will be

destroyed, causing debris to spread out in the direction the ship was

moving. Beware! A ship can also be destroyed by colliding with debris!

After a few seconds, a destroyed ship will be returned back to a

circular orbit around the sun.



If you fly off the edge of the screen, you can use the zoom keys to zoom

out, and if you really get lost you can hit `Enter` to go into hyperspace,

returning back to a circular orbit around the sun a few seconds later.

This can also be used to avoid collisions, though there's no guarantee

you won't collide with something when you come out of hyperspace.



You can also drag with the mouse to change your current view, or zoom

in and out with the scroll wheel or trackpad. Touch gestures can also

be used on devices that support them, including pinch to zoom.



Clicking on the sun will reset the view back to its initial default (same

as hitting `R`). Clicking on a ship will lock the view onto that ship,

keeping it in the center of the screen for a "first person" view of the

action. This is also a good way to see the details of the ship designs

by clicking on them and then zooming all the way in.



Observer mode lets you watch a game without having your own ship. You

can use `O` to toggle between observing and actively playing.



You can use `P` to stop and start the game without leaving the web page.



Primary controls:

^^^^^^^^^^^^^^^^^



================== ================

Key                Control          

================== ================

A, H, Left Arrow   Rotate left

S, J, Right Arrow  Rotate right

D, K, Up Arrow     Thrust

F, L, Spacebar     Launch missile

Enter, Return      Enter hyperspace

================== ================



Additional controls:

^^^^^^^^^^^^^^^^^^^^



=========== ====================

Key         Control

=========== ====================

Z           Zoom view in

X           Zoom view out

R           Reset view

C           Toggle config panel

N           Toggle names

O           Toggle observer mode

P           Play/pause game

T           Toggle timing panel

=========== ====================



Game Configuration

------------------



The configuration panel for the game will be brought up the first time

you play, and can also be brought back by hitting `C`. You can configure

a name to show under your ship and also choose whether to use WebRTC

or WebSockets for sending game updates. If you enable WebRTC, you can

also configure a STUN or TURN server. I provide a default TURN server

for the version of this game that I host myself.



Any configuration you enter is stored locally using browser local storage,

so it should be remembered across game sessions.



Acknowledgments

----------------



I want to thank some of my former coworkers at Xerox PARC for

contributing ship designs used in my original implementation of

Spacewar, which I have carried forward here!



Next Steps

----------



Find out how to install your own instance of Spacewar `here`__, or

click on the following to play my existing instance of the game:



__ INSTALL.rst



.. raw:: html