Chris McCormick

Last week Moose and I were in Birmingham for EuroPython 2009. The conference was cool and the food was really good and we met some nice folks over a few beers. The talks I enjoyed the most were Christian Tismer's talk on Psyco, and the keynotes. I am super excited that Psyco is getting the attention it deserves and some very nice looking hardcore under-the-hood architecture improvements. Cory Doctorow did his enjoyable copyfight rant, and Sir Tony Hoare did a wonderful talk about science versus engineering. The science versus engineering aspect of software development has been on my mind a bit recently since I finished reading Recursive Functions of Symbolic Expressions and Their Computation (John McCarthy, 1960), the original LISP paper. That paper has really helped me finally understand how formal mathematics can be really effectively applied to computer programming, and different isomorphic ways of expressing the same program. Because software engineering moves at such a break-neck speed I think we sometimes forget to look back at the science in Computer Science and all of the awesome theoretical work which has been done since the 1960s. You can never have too much science.

After leaving Birmingham we headed out west into the Welsh countryside in a hire car. Wales absolutely blew us away. Our mission was to drive through both national parks and visit a few castles on the way, most of which were built in the 1200s. We stopped at Castell Dinas Bram first, which is a small ruin perched on top of a hill amongst a rolling green landscape punctuated with white housed villages. We had to make a zig zagging walk up a steep hill for 20 minutes, but the climb was definately worth it. What an amazing place. Later on during day one we drove through Snowdonia National Park. Betws-y-coed looked like a nice little town that we'd love to come back and visit some time. Around the region of Llyn Gwynant, the craggy mountains with dark lakes at the bottom of valleys were breathtaking. In the afternoon we arrived at Castell y Bere which was in the middle of nowhere and slightly less ruined than Castell Dinas Bram. On a low hill and surrounded by a ring of high mountains, this place felt very Lord of the Rings-y. Much of Wales did actually, and I guess this is where Tolkien received some of his inspiration.

On the second day we explored the southern part of Wales around Brecon Beacons National Park. We visited Carreg Cennen Castle and Dryslwyn Castle in Llanarthney. Carreg Cennen was the most commercial (there was a shop and you had to pay to see it) but was also the least ruined construction we saw, so it was fun to get a good idea of the types of rooms and the size of the walls of these castles. There was a nice spooky cave at the top of the hill, under the castle, which was the first place I've been which managed to combine a fear of heights with claustrophobia. We were in a tiny dark confined space under ground, but could still look out of the stone windows at an enormous drop over a cliff. Dryslwyn was different again and quite multi-layered as it had been built and re-built throughout the ages. At Dryslwyn I tried to climb a wall and managed to trip over in the process. My excuse is that I have been wearing shoes that are slightly too big for me and it was infact the very end of the toe of my left shoe that caught, which wouldn't have happened if I had been smarter and worn shoes that fit me better. As I reached the top of the wall I managed to get stuck somehow like that, and teetered forward towards the grass, which was a foot below the other side of the wall. Unfortunately I had a camera in one hand, so I couldn't use that hand to stop myself from receiving the full impact of the fall on my face. I don't know what the other hand was doing, but it certainly wasn't there to help me when I needed it most. My knee came to the rescue later, too late, and was completely smeared in mud and grass. Luckily there was a large and well positioned pile of sheep shit to cushion my face from serious injury.

This weekend, in between watching Captain Picard versus Gandalf and having a birthday drink, I somehow managed to find some time to work on my web based games library, currently tentatively named 'JSGameSoup'. Click through the image to try out a little demo which uses it:

This demo doesn't do that much except let you fly around, but you can see where it's leading, and what the library is basically capable of. The idea is to make a Free Software game development environment which can be trivially deployed to web browsers and portable devices like Android, Nintendo DS, etc. I want to keep it completely free of proprietary technologies so that people don't have to rely on Flash, for example, to develop games for the web and beyond. I am pretty excited with how things are going. So far it seems to work well and speedily with the three majority rendering engines; Gecko, IE, and that KHTML fork that some company started. In other words, the demo runs with acceptible quality and speed on the majority of operating systems in the majority of browsers, with no fiddly tweaking - Hooray! \o/

Even though I've only just started doing it, I am really liking this new way of making and releasing games and game libraries, where I get to release them right here on this blog to you, the three people who read it. :) I really need to set up comments here as well, so I can actually get some feedback on the releases (but please feel free to email me). I think the fact that making games feels fun again, is a very good sign that I'm on the right track.

Anyway, as usual, here is the source code:

jsgamesoup-39.zip

or if you are a bazaar user:

bzr branch http://mccormick.cx/dev/jsgamesoup/

AsteroidsTNG-40.zip

or the repo:

bzr branch http://mccormick.cx/dev/AsteroidsTNG/

JSGameSoup is LGPLv3 and AsteroidsTNG is GPLv3.

The code of the Asteroids themselves is quite similar to what I posted before, except that it uses canvas commands now, instead of processingjs commands to draw. Here's the code that drives the ship:

function Ship(world) {
    this.world = world;
    this.world.player = this;
    this.x = gs.width / 2;
    this.y = gs.height / 2;
    this.angle = 0;
    this.speed = 0;
    this.points = [[0, -13], [-7, 7], [7, 7]];
    this.poly = [];
    this.lastsmoke = null;

    this.keyHeld_37 = this.keyDown_37 = function () {
        this.angle -= 0.1;
    }

    this.keyHeld_39 = this.keyDown_39 = function () {
        this.angle += 0.1;
    }

    this.keyDown_38 = function () {
        this.speed = 1;
    }

    this.keyHeld_38 = function () {
        if (this.speed < 3.0)
            this.speed += 0.3;
    }

    this.keyDown = function (keyCode) {
        //console.log(keyCode);
    }

    this.update = function() {
        if (this.speed > 0.1)
            this.speed -= 0.1;
        else
            this.speed = 0;
        this.x = (this.x + this.speed * Math.sin(this.angle) + gs.width) % gs.width;
        this.y = (this.y - this.speed * Math.cos(this.angle) + gs.height) % gs.height;
        for (n=0; n<this.points.length; n++) {
            this.poly[n] = [this.points[n][0] * Math.cos(this.angle) - this.points[n][1] * Math.sin(this.angle) + this.x, this.points[n][0] * Math.sin(this.angle) + this.points[n][1] * Math.cos(this.angle) + this.y];
        }
        if (this.speed && (!gs.inEntities(this.lastsmoke) || gs.distance([this.lastsmoke.x, this.lastsmoke.y], [this.x, this.y]) > 15)) {
            this.lastsmoke = new Smoke(this.x - 9 * Math.sin(this.angle), this.y + 9 * Math.cos(this.angle));
            gs.addEntity(this.lastsmoke);
        }
    }

    this.draw = function(c) {
        c.strokeStyle = 'rgba(255, 255, 255, 1.0)';
        gs.polygon(this.poly);
    }
}

And here is the object/class defining the little smoke particles which come out of the ship:

function Smoke(x, y) {
    this.x = x;
    this.y = y;
    this.life = 1.0;

    this.draw = function(c) {
        c.strokeStyle = 'rgba(200, 200, 200, ' + this.life + ')';
        c.beginPath();
        c.arc(this.x, this.y, 2, 0, Math.PI*2, true);
        c.closePath();
        c.stroke();
    }

    this.update = function() {
        this.life -= 0.08;
        if (this.life < 0)
        {
            gs.delEntity(this);
            this.life = 0.01;
        }
    }
}

The whole game is launched like this, where gs is the JSGameSoup() object that is automatically created by the framework:

w = new World();
gs.addEntity(w);
gs.addEntity(new Ship(w));
for (n=0; n<3; n++) {
    gs.addEntity(new Asteroid(w));
}

To me this code feels like it does quite a lot for just a little bit of work, and that's always nice.

There's something about sarien.net that really floats my boat. Maybe it's the 8 bit goodness, or maybe it's the multiplayer twist, or maybe it's the crazy technology they're using. Whatever it is, I think sarien.net is awesome.

I love that they use the term DHTML rather than any of the fancy new monikers which Javascript + markup have take on in recent years.

Prototyping is a great way of making games. You make lots of small, quick prototypes, and iterate on them to "find the fun". Scripting languages like Python and Lua are really useful in this process and there are lots of nice libraries like Pygame to assist in the process.

It would be cool to be able to include players in the prototyping loop so that your game ideas can be tried out infront of an audience and get feedback early in the process. The democratisation of game design, I guess.

I've been thinking about this a lot lately, especially as I've been going through the frustrating process of trying to get my recent gamejam entry to work under Windows. It's a pygame based game which should port trivially, but it's still a fair bit of hair-tearing work. It's not much fun to have to do such a huge amount of laborious work just to get your game ideas infront of people so that they can play them, and tell you what they think.

To this end I've been working on the Javascript game library which I wrote about earlier. Recently my efforts have been in separating it from the processingjs library into a standalone system which will run on all the major browsers. Firefox, Safari, IE6, IE7 are currently tested and working.

Hopefully you'll be seeing more links like this on here in future:

.:[ circles demo ]:.

Download a zipfile of the source of the JSGameSoup library here:

http://mccormick.cx/dev/blogref/jsgamesoup-30.zip

Or check out a branch with bzr:

bzr branch http://mccormick.cx/dev/jsgamesoup/

Patches welcome!

Another random bit of code I wrote this weekend is a set of scripts which retrieve data out of the Google universe. So far these scripts support authenticating and fetching Google Calendars, a Google Reader OPML file, and the Google Bookmarks xml file. If you'd like to get the source with bzr:

bzr co http://mccormick.cx/dev/google-services-backup/

Or download a zipfile from here:

http://mccormick.cx/dev/google-services-backup-4.zip

The code is GPL.

I like Google's services, and use several of them, but I was motivated to write these scripts after reading the following:

• Bruce Schneier on cloud computing, and what it means for control over our data
• Bruce Schneier's "An Expectation of Privacy" which touches on similar issues
• This poor fellow's story of the unexpected suspension of his Google account

"Remember when Facebook recently changed its terms of service to take further control over your data? They can do that whenever they want, you know.

We have no choice but to trust these companies with our security and privacy, even though they have little incentive to protect them."

-- Bruce Schneier