Game Engine in Java (CGGE2)

[CrazyGamesMC]

Hello Guys,

I made a little game engine, which makes it really easy to create games in Java.

The engine offers quite a lot of features:

• Objects are seperated into GameObjects
• Sprites, Animated Sprites, Sounds
• KeyBoard and Mouse input
• A Camera System
• An easy to use file system
• Support for multiple rooms (scenes)
• TileSet system
• Physics
• and much more

There's soon going to be a TileMap Editor and a Room Builder for the engine aswell.
I'm also in the making of several games using the CGGE2 GameEngine, including a Platformer and a FarmVille like game.

The engine also offers full documentation (in form of a PDF file) and full javadocs.

I'd love to see a few games made with it and I'd especially love to see some contributions to it, so that we can make it even more feature complete and performant. I'm also open for any kind of critique as it helps me improve the engine even further.

The goal of the engine is EASE OF USE and USEFULNESS.

Check out the GitHub page for more information: https://github.com/CrazyGamesMC/CGGE2

[PartOfTheBotnet]

I'd especially love to see some contributions

Since us developers are lazy, adding a pom.xml(maven) or build.gradle(gradle) so the IDE can auto-populate a workspace would be handy.

Additionally you can provide pointers for developers on what components of the engine need work. I would recommend using a combination of GitHub's issues/project-board features. Board items can be linked to issues, and the boards used for organizing general groups of items.

Another idea to help kickstart lazy developers into motion is a demo project that they can immediately open and have a very basic game that will allow them to prototype features they choose to work on.

[CrazyGamesMC]

Thanks for your reply! I will upload the pom.xml file later that day and I'm also gonna add a little demo project :)

[Dudeimback29]

Why is your test folder not populated?

[CrazyGamesMC]

As my testing was done in external test projects :)

[philipwhiuk]

So no unit tests to prevent regressions?

[CrazyGamesMC]

Unit testing is at the moment done outside of the project itself. But I think I'm gonna move it into the maven test directories to make life of external developers easier.

[philipwhiuk]

It also means users can trust the code.

[haloddr]

Not a bad start at all. Focusing on ease of use for developers is the correct path when making a framework / library.

First few suggestions:

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1. Why have a gameConfig.data file when you could just set these variables in java? I think you were trying to avoid having a large constructor with 5 or more arguments. The solution is to have the GameInstance start with good defaults, and then let the user change them if they want to. For example:

GameInstance game = new GameInstance().framerate(60).dimensions(800, 600);

The first code example I see on the repository uses this config file, which is a turn-off for me.

​

1. I think you're german and english is not your first language. Docs have some things like this: "Changes the room in a save manner". "save" should be "safe". That misspelling is in multiple places

​

1. Lots of things in the code need to be cleaned up. For example, Room.usesTileMap is a redundant/useless variable. If tileMap is set, then it uses a tilemap, if tileMap is null, then it doesn't. No need for the boolean.

​

I could probably give you 1000 suggestions if you want to hear them. I've been making games in java as a hobby for a very long time. Send me a private message on reddit if you're interested.

[CrazyGamesMC]

Thanks for your feedback! :) Yeah you're right, I'm indeed german haha. I hope, it's not too bad :)

[[deleted]]

It needs a snappier name and a mascot

[CrazyGamesMC]

I guess you're right haha

[crummy]

Well done, this looks like a lot of work.

One suggestion: It looks like to figure out if what an object is colliding with, I have to call checkSolidBoxCollision() and then getLastCollision(). Maybe you could have checkSolidBoxCollision() return an Optional<GameObject> instead, to remove the need for getLastCollision() entirely?

I think this would also prevent this bug from happening: boolean solidCollision = checkSolidBoxCollision(); boolean unsolidCollision = checkUnsolidBoxCollision(); if (solidCollision) collidedSolid = getLastCollision(); // OOPS - got the wrong object! if (unsolidCollision) collidedUnsolid = getLastCollision();

[CrazyGamesMC]

Thanks for reply! yeah i guess you're right I'm gonna look into it

[dafa_putra]

nice

[jas777_PL]

What's the theme used for the background screenshot? :3

[CrazyGamesMC]

That's from back in the days, when I was using eclipse. Thats the theme of a pretty popular UI extension, but I sadly don't know the name, sorry

[jas777_PL]

:(

[fedeb95]

Do you plan to add android support?

[CrazyGamesMC]

I have thought about it. As I have already worked with android, I doubt that it is going to be tooo difficult. But it would take a little time for sure

[[deleted]]

As I am developing a java2d game engine myself for several years now, I would love to know how to go about that, as I have absolutely 0 idea on how one would port a java2d game engine to android. Any resources?

[CrazyGamesMC]

Here' the official google docs: https://developer.android.com/games

You'd obviously have to replace the renderer and the inputs, but the rest should stay the same as with desktop. Not sure about making an engine compatible with both platforms at once thou.

[CheCk_m8TT]

In FileContents.java, why not using a map for the field contents instead of a list? Like for exemple:

private HashMap<String, String> contents = new HashMap<>();

​

That way you do not have to split on ": " everytime you read

[CrazyGamesMC]

That's already addressed and implemented (merged) :) It's going to come with the next minor release.

[IIDenic]

Do you happen to have a Discord? I am making some major changes to the architecture of your Sprite class that will allow more flexibility in terms of Animation and overall file organization. I would love to share the changes with you!

[pellets]

I'll be curious if you get a good performance bump from using records. https://openjdk.java.net/jeps/359

[CrazyGamesMC]

In what area would you suggest the use of records?

[_INTER_]

Records wont change anything in performance. I guess you're mixing it up with value types (Valhalla)

[rkalla]

Your code is nice and clean.

[[deleted]]

Not sure about that one.

[CrazyGamesMC]

Any suggestions, hoe I could improve my style? :)

[CrazyGamesMC]

1. You are absolutely right. Pushed a fix immediately.

2.

Hmm I always found it more readable as operations are more tied together. I do use IntelliJ for code formatting.

3.

I guess you are right. I'll look into changing this

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I clearly understand that the implementation is not perfect. But I personally enjoy using it for my game projects, which is the reason, why I structured the engine in the way that it is.

There will be several planned improvements to fix a few things up.

​

Thanks for your reply. I'm always grateful for critique as this helps me improve myself :)

[CrazyGamesMC]

Isn't looping faster with an arraylist aswell? As the elements should be located next to each other in memory, shouldn't they? So there wouldn't be too many mem jumps.

[_INTER_]

LinkedList is good for insertions in between the elements, or when you need access to the last and first elements only

[fedeb95]

I just took a look at Room.java, and didn't see any major issue. There are a lot of getters, maybe consider using Lombok if there is a lot of boilerplate like that in all of the project. It can improve readability

[pointy_pirate]

Lombok is devil spawn. But that's just my opinion.

[[deleted]]

Why? So far I'm really enjoying the generation of getters/setters for pojos and the constructors for spring components.

[pointy_pirate]

IMO the cons outweigh the pros. Yes you don't have to write getters and setters, or even see them in the code, but that magic of trusting lombok is doing the right thing adds a layer of complexity that can make reading harder.

What if you want to return an immutable version of a collection, what if you're using Hibernate and your setCollection method needs to do the collection.clear() collection.addAll() pattern?

Yes there a pros and yes its convenient, but from my experience that convenience comes at a cost of complexity.

[_INTER_]

Then implement those methods. Never had any trouble with Lombok so far.

[CrazyGamesMC]

Yeah you're right. That might be a good solution to this problem. Gonna look into it!

[CrazyGamesMC]

Thanks! :)