README
¶
This is JohnRoids. A simple but addictive game whose sole purpose is to kill John.
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
nick@craig-wood.com
@njcw
2018-07-14
Documentation
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Overview ¶
JohnRoids - the conversion!
note that the error checking for object table full has been taken out...
make a rand_chance (x/y) function
Note that object 0 is the ship ¶
Speed goes wrong when we have the ghostship countdown ¶
Need to figure out what happens on gameover! gamepause should be in main loop really...
Try making an explode image function which makes an object per pixel in the object and gives then the right velocities to make an explosion. Could then have a fade table for each of 256 pixels. Will run out of objects pretty quickly! Perhaps only want to explode every 10th pixel in the roids or something like that. Could record the x and y of the hit and use that as the centre of the explosion.
Could reduce the width and height of the sprite by removing all the black rows at the top and the bottom left and right. This would speed up the plotter and enable us to calculate the c of g so we could split the roids so that the bits always came apart from the centre.
Could make the explosion always start from the bullet hit - this might be quite realistic.
Index ¶
- Constants
- func Asset(name string) ([]byte, error)
- func AssetDir(name string) ([]string, error)
- func AssetInfo(name string) (os.FileInfo, error)
- func AssetNames() []string
- func MustAsset(name string) []byte
- func RestoreAsset(dir, name string) error
- func RestoreAssets(dir, name string) error
- type Game
- type KeyCode
Constants ¶
const ( SW = 320 SH = 256 MinMsPerFrame = 20 )
Variables ¶
This section is empty.
Functions ¶
func Asset ¶
Asset loads and returns the asset for the given name. It returns an error if the asset could not be found or could not be loaded.
func AssetDir ¶
AssetDir returns the file names below a certain directory embedded in the file by go-bindata. For example if you run go-bindata on data/... and data contains the following hierarchy:
data/
foo.txt
img/
a.png
b.png
then AssetDir("data") would return []string{"foo.txt", "img"} AssetDir("data/img") would return []string{"a.png", "b.png"} AssetDir("foo.txt") and AssetDir("notexist") would return an error AssetDir("") will return []string{"data"}.
func AssetInfo ¶
AssetInfo loads and returns the asset info for the given name. It returns an error if the asset could not be found or could not be loaded.
func MustAsset ¶
MustAsset is like Asset but panics when Asset would return an error. It simplifies safe initialization of global variables.
func RestoreAsset ¶
RestoreAsset restores an asset under the given directory
func RestoreAssets ¶
RestoreAssets restores an asset under the given directory recursively
Source Files
Directories