Yes, it's that time of year again. When some really amazing game developers try to fit as much game as they can into 4k of compressed java bytecode. There are some AMAZING games so far this year. And there are 2.75 months left in the competition....

The link above has threads to the games being entered so far. I should warn you that miners4k, speed4k, frag4k, and roll4k are quiet addictive and you'd never believe they were made in as little as 4096 bytes. Give em a try! JRE 1.4 required.

Heh, I've spent at least 4 hours playing miners4k (it's a lemmings inspired game with little miners in search of gold) and I can't get past level 3. One of the other guys beat it and he said there are some growing slime monsters in the later levels that eat your little miner guys. This game is amazing.

It's hard to say exactly what everyone is doing. Like I'm using a jframe and a buffered image and doing my own double buffering, others are using the built in double buffering (getGraphicsConfiguration()), last year I made an applet. It's pretty free form. Here are some tips someone posted;

Here's a tip; use enableEvents() to poll the keyboard directly:

Here's a screen shot of my software renderer with flat shading in about 2.7k. Unfortunately I don't have alot of time over the next two weeks to do anything with it

{"name":"j4k.png","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/5\/7\/57c11edb8da189dd4ffc74b37e5baefe.png","w":343,"h":310,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/5\/7\/57c11edb8da189dd4ffc74b37e5baefe"}

I think your code for keyevents may be smaller by a few bytes. I'm not at the point of scrounging for bytes yet, and when I do I'll have to check into that. Some of these people disassemble there code and tweak it with a java bytecode assembler. I'm not at that point yet!

Yes, System.currentTimeMillis() can be pretty erratic; but on win2000 xp its usable. This is my current main loop:

while (true) {
    if(System.currentTimeMillis()-dt > 10) {
        //Game logic, input, physics, etc go here

        dt = System.currentTimeMillis();
    }     
    paint(getGraphics());
}

So I draw as fast as it'll go, but only update the game 100 times a second. It seems to run pretty smooth on my computer.

Heh, I had the only applet in last years contest. So far as I know there is no limit on memory usage in applets. Also, applets have the method getAudioClip() you can use to play midi, wav, and au files. You might look into using those.

I have an idea on how to create ALOT of content for a sidescroller:

1) store a few tiles and sprites as byte arrays; for 16 colors tiles you can fit two pixels per byte, 4 colors can fit 4 pixels per (edit)byte. You can switch up colors by using different palletes. You could procedurally generate some tiles too by drawing into an image with gfx primitives (rects, circles etc...)

2) When you create the buffered image from the byte array multiply by a factor of two. This will give you an old school, low res pixelly style to your gfx.

3) Store tile map data in byte arrays using RLE (run length encoding) and decompress that into an int[] for your tile map.

OR

4) Use 'bitmaps' of tiles and draw them into the tile map array; ie reuse one platform, reuse a platform with a ladder, reuse a palmtree top, whatever.

I'm sure I could squeeze one hell of a lot of content using this method. The hardest part would be platformer physics.

If you have java 1.4 plus and click on the link it should kick off webstart and ask you to download and run the application. Mozilla ask me to open with default application; I'd google for how to enable webstart on whatever platform your on.

I thought about generating the sound procedurally to, I guess it would take up some space as there might be lots of class references. But I'll look into it if I have any space left when I am done with the game (even a "boing" sound when jumping in a platform game would enhance the game a lot).

It would be interesing to see the result of your method. I suspect that it might prove not to be as effective as you think. That is the size of the compressed file, it probably won't compress your data as good if you store it in a way which is more space optimal. But as I said, interesting it would be! (Yoda talk tm)

If you were in my situation. You need to be able to create bitmaps and process the pixels in these (I'm going to apply my own image effects, think "Blur"). Then use a number of these within the game for animations. Would you use Image or an BufferedImage then? (I am sure you are much better at Java than me, so I'm taking the opportunity to ask.)

Yes I agree, couldn't resist joining in. You should join as well! It would be fun with many allegroids in the compo.

Thanks once more! BufferedImage's it is!

Are you going to have the Death Star in there as well? Like in the original arcade game. Sounds cool!

My game:
I can reveal that I have my mind set on a Bomberman clone, I checked out the forums at Javagaming and couldn't find one.

It's not going to be easy though, I have the game loop ready together with a small draw tilemap test. And I am already at 3024 byte size of my class file.

I will be implementing in this order:

• Create a test tile map with two tile types; walls and walkable.

• Control of the main character as well as drawing him.

• Draw the walls more nicely (procedural graphics).

• Be able to drop bombs, which will explode and break walls.

• Computer controlled characters of the same type as our main character. Simple AI using a finite state machine.

• Main character and Computer controlled characters can not walk into square with a bomb or another character.

• Characters die from bomb explotions as well.

• Replace test map with a procedurally generated map which you give level_difficulty to as an argument.

• Make a small menu and increasingly harder levels by feeding the map generator with a higher difficulty level.

We will see if it will result in a finished game with the above qualities. Probably not, but I'll do my best.

Uncompressed and with debug information, so I might have enough space to finish it as stated above.

Nice! I hope you will have time and feel like it later on.

Seems like it. I think it's perfect with a long time span like this, not everyone can dedicate their time to game development for a couple of days. This way almost anyone have a chance of completing.

I thought I wouldn't feed it. Rash, if you use Eclipse like me it constantly compiles the game, so when I press "Run" I need to wait about 1/3 second before the game starts. It's certainly better than any C/C++ development environment I know of. But language wars are really boring, check nonnus29's sig for my opinion! It's much more fun if we keep the thread on topic.

That's nice, gives me some hope to finish the bomberman game then! If I have enough time I might create two games, it was very fun indeed!

[edit] BTW, I am DonaldEKnuth on javagaming.

[edit2]
I have a finished game now as an applet. I tried reading on how to put it in a jar file and have used jar cf jarfile.jar G.class java.policy.applet G1134013040968.html without success. It creates a jar-file, but when I double click on it I get the error "Failed to load Main-Class manifest attribute from c:\d\jarfile.jar".

Do you have any hint? I'm new to this stuff, I read in Sun's tutorial but it didn't help. Do you know how they want people to turn in their applets? (Most other people use webstart, but I've created an applet.)

Oh, nice! Thank you!

This is what I have currently, I am creating a Sokoban clone:
http://www.freeimagelibrary.com/images/mrpeanut/sokoban4kv0.png

I have lots of bytes left, I am currently at 3174 bytes with:

• Different coloring on each level based on some factors.

• >60 levels.

I might add (strikethrough means done):

• Smooth movement (the player square moves in steps now).

• More random graphics.

• A game menu.

• Some effects.

• Clean things up a bit.

• A blip sound when moving.

• Look into the webstart thingy and run it through it instead (as most seem to do).