Greenfoot limits

Greenfoot is an engine (I guess). This means that Greenfoot offers an API with methods useful for making small games and scenarios. Having that said Greenfoot is coded using Java, which means that Greenfoot is basicly Java. You can't really convert Greenfoot projects into simple Java unless you implement all the Greenfoot methods yourself which isn't that easy. Though you can easily convert Java projects into Greenfoot projects, because Greenfoot is using Java.

Oh okay I get it now. As I said Greenfoot gives you methods for working with small games and scenarios in 2D. If you want to make 3D games you should find another engine or API or whatever. Even though 3D is possible i Greenfoot (like in this scenario) it's not what Greenfoot is made for.

Greenfoot is good at what it's designed for - making it simple to create 2D games - but 3D is where it falls down. I've made 3D games for it (which I haven't uploaded due to them not running well - I do have some example 3D scenarios uploaded though), and honestly it just doesn't fit nicely into the way Greenfoot is designed. Multiplayer, however, *is* possible in Greenfoot (which I don't think many people realize). However, it doesn't really work on scenarios uploaded to the Greenfoot gallery. It does, however, work on downloaded versions of scenarios. For example, I have a multiplayer game (which I never uploaded due to multiplayer not working on the gallery) which my brother and I play from time to time (he on his computer, me on mine, connected over the network), and it works. 3D and online multiplayer are advanced topics though (the jump from 2D to 3D is very large), and once you get to the point where you want to be making those I suggest using a different engine. I personally recommend Unity - you can't do Java in it, but you can code C# in Unity (along with a couple of other languages if you want), which is a very similar language to Java.

A Greenfoot game is already Java. Greenfoot is a development environment and a graphics library for Java.

What will be new in the construction of classes and in general if I switch to java? Is it hard to switch or are there many new things to learn before starting to code? P.S.: I don't want to switch now :P but maybe in some month or so I wanted to learn 3D

Greenfoot IS Java. As others have said, it is a 2D graphics engine and a Java IDE. If you want 3D, you need a different engine (check out J-Monkey) but the syntax is the same (except of course you won't have Greenfoot classes like Actor and World, instead you'll have a very different set of classes to work with). In other words, everything you learn to do in Greenfoot will give you Java experience that will help you with any other Java you do in the future.

If you're using Greenfoot you're already using Java. It doesn't make sense to say "switch to Java". I guess what you mean is "move away from Greenfoot". If you want to write similar games as you do in Greenfoot, but without using Greenfoot, then yes, there is a lot to learn; you'll need to deal with Swing or an equivalent toolkit to do your user interface, and you'll need to write code to manage the things that Greenfoot does automatically (like paint the world and the actors in it). But the language is the same.

Yes I should say move away from Greenfoot then. What I don't realize is what Greenfoot does automatically. When you say painting you mean that on java without Greenfoot you have to make function to paint every pixel of an image? What is Swing? And what exactly is an IDE?

It means you have to write code to paint the images, yes, but it doesn't necessarily mean you have to work at the pixel level. Greenfoot uses Swing (and AWT) to do its image manipulation and painting. It's the standard GUI toolkit for Java. See wikipedia. An Integrated Development Environment .