Imperial College’s bid to host the Inter Varsity Dancesport Competition in 2006 has been succesful and I’m on the “support team”.

Wohoo!

The current version of Galaxia Reborn is now available to play with. You can’t actually do that much but some things are still fun to play with.

Signup works but doesn’t actually give you anything you can use so just login as “Q” with password “q”.

You can move ships around and build more at the colony (you have to find the colony first though :P) although you can’t send them into space just yet. Also, the entire interface has been translated into Finnish (well almost. Two little bits were added afterwards but they’ll get done soon enough). Thanks for that go to my girlfriend Julia. If anyone is interested in translating the interface into a different language let me know . You’ll get a permanent link on the info panel at the bottom for people using your language as well as a mention in any credits.

Galaxia Reborn

Another installation that was easier than I expected.

I now have PHP5 installed alongside PHP4. It lowers efficiency a bit since it’s installed as CGI instead of an Apache module but for testing it’s fine :)

For anyone planing on doing this who isn’t too familiar with installing stuff via the command line on Unix-like OSes (like me), there is a very usefulguide from Scott Huring.

Not that it really makes much difference yet, I’m now running MySQL 4!

The upgrade was easier than I expected with the only problem not strictly being an upgrade problem (I had to manually kill MySQL and restart it to get it to recreate my socket file). This is all preparation for installing PHP5 so everyone can actually see Galaxia Reborn.

Just to clear things up about why I mention this when there are a few other similar things out there. This one truly is decentralised. Somewhere on the page you use as an ID is the address to your OpenID server. This site has a diagram explaining it all.

Well I have OpenID working at a basic level in Galaxia for signing up and logging in.

For signups though a user still needs to provide a username eventually to replace the url which will generally be too long.

I just noticed something on LiveJournal I hadn’t noticed before… OpenID. It’s a clever idea - a truly distributed identity management system. The idea is to allow you to login to websites using just a URL (in my case http://www.oliverbrown.me.uk/) and have everything done automatically.

In detail:

You login into a website that supports OpenID (like LiveJournal). The browser then checks that URL you gave for a bit of HTML that specifies your home server. The website then redirects your browser to that server and logs you in (and because of the joy of cookies etc. this should be automatic). The server then asks if you really want to share your identity with the site you specified and if so redirects back to the original site which now knows you are who you say you are (i.e. the owner of the url and actually registered with the server you specified).

It’s confusing but clever :)

Introduction to XGS

This won’t sound that impressive since noone has seen any of GR working but I have scripting working at a minimal level in Galaxia Reborn.

I gave a ship the following script:

<xgs> <script event="entersector"> <savetomemory name="w" value="($w+1)%4" /> <setcourse target="$waypoints.$w" /> </script> </xgs>

$waypoints is simply an array of four coordinates. The function savetomemory just saves data to the ship which is read back in when the script next executes.

Not something I want to go into in depth, I just figured I should mentioned it before I post something since it’s all over the news while I type. http://uk.news.yahoo.com/050707/140/fmtu4.html

Guess I picked the right time to leave London.

The user scripting I mentioned before I went to Brussels is now basically done. The most amazing part is that I did most of it while I was in Brussels on a computer without PHP (amazing because apart from a few minor typos it actually worked).

The whole thing is actually simpler than I expected it to be and as such it can do stuff I didn’t plan. The first is maths expressions. This is something that may cause a problem however since it just just evals the code (after substituting variables and stripping possible harmful stuff).

The coolest feature I think though is handling aggregate data types. When you call a script you also pass it an array of variables. These variables can be of any type from integers or strings to arrays or objects (or even resources); it’s upto the functions you define to actually handle them. Now different elements of arrays and properties of objects can be accessed using a slghtly suspect-looking dot notation. So (from a working example I wrote) you could use something like $fleets.1.name which would access the name of the second element of the fleets array.

It’s worth pointing out that I decided to stick with numbering arrays from 0 since as a programmer that’s what I’m used to.

Anyway when I say that is accesses the name of the second element, it checks the type of the element and accessed it as an array ($fleets[1]['name']) or a property ($fleets[1]->name) as appropriate.

You can also do $fleets.$n.name to access the name of the nth element (although be warned that if n doesn’t reference a key of the fleets array then it won’t work obviously). Which brings me to biggest problem with it at the moment… everything fails silently if something isn’t right.

The way the scripting is called is also more flexible than I originally planned. The first way is:

$xgs->parseXGS('event', 'fleetentersector', $script, $vars);

$script is the a well formed XML script and $vars is an associative array of variables. Any script tags with an attributes of event equal to fleetentersector (<script event="fleetentersector">). This is was done mainly with Galaxia in mind so players could create different types of scripts other than ones designed to respond to events (i.e. use it just to create a batch command system).

The second far more flexible way to use it is:

$xgs->parseXPath($xpath, $script, $vars);

Where $xpath is an XPath expression selecting the root node of the script. Just to point out the first example actually just calls that with XPath expression "script[@$type='$att']" ($type is the attribute name and $att its value).