github.com/ncw/johnroids

This is JohnRoids. A simple but addictive game whose sole purpose is to kill John.

Play the game online.

See also Technical Writeup

I wrote this game originally in 1991 on my Acorn Archimedes to annoy John when I was bored one rainy afternoon. John came round and instead of being annoyed played the game for hours and hours - there is obviously some kind of perverse thrill in shooting oneself!

Back in 1991 digitised pictures were still something of a rarity. I made the one of John from a camcorder video and an extremely hacky black and white video digitiser which I built myself. Note there are actually two images of John - one looking happy and the other not!

The original was written entirely in ARM assembler to make it go fast enough. However I thought the program deserved not to wither away so in 2001 I ported it to C and SDL and in 2018 ported it to Go to run in the browser so many more hours can be wasted shooting at John.

When you run the game you'll notice the playing area is rather small (320x256 pixels). I'm afraid this was all that was available in 1991! I tried making the playing area bigger but the game lost some of its visceral thrill, so you are left with a small screen. If you want it bigger use the zoom function of your browser.

This is an entirely faithful conversion of the original except for the fact that I haven't put the sound back in yet. The original samples are in a very strange format I haven't managed to translate.

You can find the source code on github - report issues and send fixes there please!

The instructions are printed on the screen to start, but to summarise they are:

Z      - Rotate left
X      - Rotate right
Shift  - Fire thruster
Return - Fire gun
Space  - Start the game

If you press "Toggle Keyboard" you'll get an onscreen keyboard which works pretty well on mobile devices.

Shoot everything before it touches you. Note that you lose a point of score for every bullet you fire. Some of the roids may shoot at you - using thrust is a good idea at this point. Things get very hectic as you go through the levels.

Installation

This repository contains 3 implementation of johnroids for SDL, gopherjs and go/wasm.

If you want to try it locally then do

go get github.com/ncw/johnroids/...

And run the johnroids-sdl binary.

Note that you'll need the SDL headers and libraries installed for this to work.

You can play the gopherjs and go/wasm versions online.

To build these versions cd to johnroids-js then make build then make serve. You may have to alter the path to your go1.11 binary in the Makefile.

Enjoy

Nick Craig-Wood
[e-mail]
@njcw
2018-07-14