June 29, 2009

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:

AsteroidsTNG revision 40

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.

June 19, 2009

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.

sarien.net - King's Quest 3

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.

June 14, 2009

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!

June 8, 2009

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:

"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

June 8, 2009

This weekend I wrote a Django powered replacement for this blog which was previously running on the text-file based pybloxsom engine. Unfortunately I found the pybloxsom code too time-consuming to understand and modify, and so I've re-written it using the Django framework which I know much better. It still uses a text-file storage backend, but the code is smaller and easier to understand. You can download the source code to 'django-bloxsom' here:

http://mccormick.cx/dev/djangobloxsom-6.zip

Or with bzr:

bzr co http://mccormick.cx/dev/djangobloxsom/

The templates are hardcoded for my site, but are easy enough to modify, and the code is fairly generic. The textfile based blog data is cached so it doesn't get read from disk every time the page is accessed, so you can use something like memcached for lightning fast page loading. I am hoping to add comments, and pagination soon since these are the features I couldn't work out how to add to pybloxsom. Anyway, hopefully this will be useful to someone.