Little Spikey Land - java

Well now with the release of the latest version of JPL I have finally got restoring from backups implemented. People have been asking me to do it for a while, but it's only recently that I have had the time and a spare Psion to backup, then wipe, then restore.

In principle this was the only thing that MacConnect could do that JPL could not, so although it's not quite equivalent to PsiWin yet JPL is definitely on the way!

posted at 8:04 PM John

Well now I'm happy!

I have made the parameter that controls an agents "field of vision" evolvable. In this case all agents started off with fields of vision of 180° (ie they can see in front and to the left and right). I created two species one coloured blue and specified as being herbivores, the other coloured red and carnivorous. The interesting thing is that after a while the carnivores and herbivores have differentiated by field of vision quite well.

In the above picture you can see (from the black lines) that the herbivore now has a field of vision that allows it see partially behind it. This is great for when it is being chased (particularly as the carnivores are slightly faster). Conversely the carnivore has a field of vision that is slightly more forward looking. This lets it stay a bit more "focused" on it's target.

The best thing about this is that this is what you would expect from real life predators and prey. Think cat (forward looking) versus mouse (eyes on side of head, lets it look around).

The only weird (but still interesting) thing at the moment is that the predators tend to stay in one place and turn on the spot. This seem to work fairly well as they can scan the "horizon" for incoming herbivores and pounce on them when they appear!

posted at 6:08 PM John

Here is a screen shot of part of my mini project. It shows the "Species Dialog" that lets you control the parameters of the agents. The coolest thing about it, is that you can change the number of sensors and the agents field of vision. You can have forward looking predators and prey with 360° vision if you want, or combinations in between.

Edited on: Saturday, November 22, 2003 10:53 PM
posted at 10:52 PM John

Did a bit of work on making myself a gallery generation program. Basically I want something so that I don't have to do too much to add new pictures, but that will give me a fair bit of flexibility. As like a lot of programmers I have chosen to "roll my own". It's partly for the sake of it and partly so I can make it do exactly what I want it to do.

Anyway, here is a screen shot of a gallery it has made. The interesting thing here is that the thumbnails were generated automatically and still look reasonable, even though the original pictures were all sorts of different sizes. At the moment it is biased towards using the top left of an image for a thumbnail, but I want to make that user controllable too. In the mean time it'll be a nice bit of "relief" programming when I want to procrastinate. ;^)

Also done another inked picture.

Edited on: Friday, October 17, 2003 8:39 PM
posted at 8:38 PM John

Well I finally took the plunge and upgraded to MacOS X. I know that Panther (OS X.3) is out in about 2 weeks, but I went for Jaguar (OS X.2) as I didn't want to wait. When it comes down to it Jaguar runs Java 1.4 and that's what I really want.

So far I am impressed with OS X. It's really nice being able to force quit programs that freeze and not take the system with down too. It's also pretty looking ;^). Oh and my favourite little feature is that when you drag an item off of the Dock (to remove it) it then disappears with a little cloud of smoke and an accompanying sound! I think it's the little touches that will make OS X fun.

My only niggle is that Safari (Apples custom built browser) won't do google queries from the main page, but it will from it's built in google search box thing. It's a bit bizarre, as Internet Explorer handles this fine. I suspect it's partly my setup, i.e. connecting through a Windows 98 box. I do also get similar problems with my Linux box, so I am not too worried.

Beyond that my scanner, cd burner and graphics tablet all work fine. The graphics tablet lets me use Inkwell, which is quite good fun, but I'm not sure how useful it will be in "real life". I did have to get a new USB serial adapter, but that was only £20 from Expansys so not bad.

I also got JPL running and it seems to work pretty well. Considering I have been developing it on entirely different operating systems it runs well. At least now I can fix some of those little problems (mainly with GUI elements). Anyway here is a screen shot of it running.

Edited on: Friday, October 10, 2003 7:59 PM
posted at 7:56 PM John

I wrote a little java version of the MacOS program called "Stickies", which lets you leave virtual post-it^TM notes on your screen. It's called Jammies, because Jam is sticky and I couldn't think up a better name. I have it setup so that it starts up when I login. It should remember how it was when you left it (including whether it was minimised or not). It's only a tiny program so Java is probably overkill. Maybe I should write a tiny C version for Linux...

... just uploaded a version which slightly simplifies changing colors and closing notes.

Edited on: Monday, October 06, 2003 12:35 AM
posted at 9:51 PM John

It's been a while since I bought any Java books and now I've just gone and got two. I guess it's because I'm heading off to Uni again and want to brush up on a few things.

The first book was JDK 1.4 Tutorial, which covers the new features of java 1.4. It makes trying to grok the new APIs a lot easier.

The second is Java Extreme Programming Cookbook which I have wanted for some time. This one is going to be very useful as it covers things like Ant and JUnit. I've already set up an Ant build file for JPL and I shall soon be writing some unit tests, which will help ensure my code is much more robust.

Edited on: Monday, August 25, 2003 5:29 PM
posted at 5:07 PM John