Sunday 10 March 2013

Scene2D Investigation... Result: Quack Attack Free Duck Hunt Game!

I started looking into LibGDX Scene2D recently. No real reason, other than it looked like it could be something interesting to learn, so why not! :) Best way for me to learn is to just get stuck in, so I got to work on a Duck Hunt tribute, and learned as I went along...

It's clear that Scene2D UI is the way to go for menus and the like, so much cleaner than my past approach. Scene2D UI combined with table-layout makes setting up menus and HUDs a breeze. Even better, tweaking layouts becomes pain free, a real bonus! I'll certainly be using it again in future games.

As for making use of Scene2D in the game itself (over and above the HUD), it was tricky to start with... All the tutorials I've read so far have advocated the MVC approach, and it seems that MVC is not really possible when using Scene2D (the model and view are tightly coupled). Still, I've not been doing this long enough to be stuck in my ways, so I figured I could just ignore some of what I'd learned in my earlier projects and just go with the Scene2D flow.

I was surprised that there aren't more tutorials available on the subject to be honest, but I muddled through with various bits and pieces I could find. The most valuable resource when getting started was the LibGDX suite of tests, they are always a good starting point when looking at something new. The official wiki was helpful too. It's a bit presumptuous to think that I'm in a position to write tutorials on the subject (due to me being a newbie myself), but I think I'll post a few code snippets in the coming weeks to share some getting started tips, maybe even an open source step-by-step mini game "how to" if I have the time.

I like how Scene2D lets you encapsulate Actor behaviour in its own act() method, it's pretty cool just instantiating an Actor and then just leaving it to its own devices. My first Scene2D game (Quack Attack) has the game logic class spawn a Duck object at various intervals, the Duck class itself keeps track of how it should behave (overridden act() method sets various actions for the duck to perform dependent on its current state), and it also takes care of drawing itself via the overridden draw() method. It's really nice to be able to look at that single Duck class and immediately "get" exactly what a duck will do in the game, without having to look at various other classes. I guess this is one of the main Scene2D strengths, but on the flipside it's what makes MVC impossible...

I'm sure the coupled view and controller will make things difficult on larger more complex games, but for simpler games I don't think it's a big problem. I guess if I were ever to try porting a Scene2D heavy game to a different platform it'd be a problem too, I am pretty sure porting Racing Game or Evil Monkey Touch Defense or Zombie Game to XNA would be pretty straightforward (if we ignore the tilt/touch control issue), but porting Quack Attack to a library without a similar scene graph implementation would not be so straightforward (would probably have to port the whole of Scene2D too!). Again I don't really care about that right now as I'm focusing on Android only, so I think it's quite likely that I'll be using in-game Scene2D in the future.

I've just published my first Scene2D game on Google Play, it's totally free (ad supported), so feel free to install and check it out. If you like it, I always appreciate a nice rating/review :) Check it out here:

I think it turned out quite well, and am pleased with what was achieved in a relatively short amount of time. Keep an eye out for future blog posts featuring mini Scene2D tutorials if you're interested in that kind of thing :)

Until next time - happy gaming, and happy game developing!