Box2DSprite: easily draw Sprites on Box2D Bodies and Fixtures

Shared Code
#1

I wrote a little subclass of Sprite to make it easier to draw my Sprites at the correct position using Box2D and LibGDX. You can find it on Bitbucket.

Just create a Box2DSprite and put it in the user data of a Body or Fixture and it will draw positioned, sized and rotated according to what you put it in.

Code example:

Body body = world.createBody(bodyDef);
Fixture fixture = body.createFixture(fixtureDef);
Box2DSprite box2DSprite = new Box2DSprite(someSpriteOrTextureYouHave);
body.setUserData(box2DSprite); // will draw on whole body
fixture.setUserData(box2DSprite); // will only draw on the Fixture

To render, simply do:

batch.begin();
// renders all the Box2DSprites in the given Box2D World
Box2DSprite.draw(batch, world);
// renders just this Box2DSprite, but you have to give in the Body or Fixture to render on (this way, it doesn't have to be in the user data)
box2DSprite.draw(batch, body);
box2DSprite.draw(batch, fixture);
batch.end();

Here is a little example Screen:
example

NOTE: To use this, you also need my Box2DUtils class which is dependent on GeometryUtils.

[b]This is now part of [url=http://dermetfan.bplaced.net/libgdx-utils.php]libgdx-utils[/url][/b].
#2

The last part of the code, in the render, what is “fixtureToRenderOn”? I don’t understand it…

#3

I guess it’s pretty much simply the Fixture instance you want to render.
‘fixtureToRenderOn’ might be a little bit mis-named.

#4

Yep, exactly this. Since a FixtureSprite doesn’t hold a reference to a Fixture, you have to provide one. I changed the name to something longer and more confusing (hopefully not ;D).

#5

How about ‘fixture’? :smiley:

#6

Why didn’t I get this idea in the beginning? :clue:

#7

I’m having problems with put a image in a body, so, now I will try this method.

#8

AnimatedFixtureSprite now also available. You need an AnimatedSprite to use it.
Updated original post.
You find basically everything in one place here.

#9

Greetings.

I’m trying to get your code to work but was unable to.

First off: I had to change your draw method in your FixtureSprite.java because world.getBodies(tmpBodies) wouldn’t work (The method getBodies() in the type World is not applicable for the arguments (Array))

I replaced it with the following code:


public static void draw(SpriteBatch batch, World world) {
    Iterator<Body> wIt = world.getBodies();
        while(wIt.hasNext()) {
            Body body = wIt.next();
            for(Fixture fixture : body.getFixtureList())
                if(fixture.getUserData() instanceof FixtureSprite)
                    ((FixtureSprite) fixture.getUserData()).draw(batch, fixture);
         }
}

After this i created a SpriteFixture with a 64x64px Texture and added it to my circleBody (Radius 15F)

circleBody.addUserData(spriteFixture);

and tried both render methods without success.

Do you have an simple example for us?

Kind regards,

Drabla

#10

Thanks for your interest in this :slight_smile:

You changed the draw method to pretty much what it was before some LibGDX update. I suggest you update to the latest nightlies, it should work without changes then.

Note that the line

world.createBody(bodyDef).createFixture(fixtureDef).setUserData(new FixtureSprite(sprite));

adds the FixtureSprite to the user data of the Fixture, not the Body. This is because it allows to render on each Fixture of a Body seperately, which gives this the name FixtureSprite :wink:

Here’s an example (I also added it to the original post). If the link doesn’t work for some reason, use this one.

#11

Oh my, thank you :slight_smile: Sorry for wasting your time ^^ It’s late it guess .>

Everything works perfectly now. Thanks for sharing!

Kind regards,
Drabla

#12

Very nice. I’m also very interested in the AnimatedFixtureSprite. Thanks for putting in the time and effort to make these utilities!

#13

I am going to be “that guy”.

How do I actually download the source in a zip, the branch gives a totally different commit, can’t see the files anywhere.

Also looks great, new to game development and drawing sprites to the bodies is just cumbersome hehe.

#14

Sorry, the links were a bit outdated.
This is now included in my mini library which grew a bit so it’s in its own repository now. You can download a jar there and put it in your project like you’re used to from other libraries.

#15

Thanks! I am looking forward to using this.

Currently practicing by making games from the past, Pong, Pac-man etc etc, all these little libraries help me keep things neat and lower the confusion! :smiley: :smiley:

#16

I have just one more question.

I will obviously be using this in my own projects, will I have to change the package declerations all the time or is there some sort of method to do this automatically, I mean at the top it has:

package net.dermetfan.libgdx.math;

Which is obviously different from my projects package, but even if I change it, when I go to reuse…well, repeats all over :smiley:

Any ideas?

#17

Glad it helps you :slight_smile: The library also contains other classes that might be useful for you, like the AnimatedSprite (there’s a Box2D version as well).

[quote=“Gibbo3771,post:16,topic:42439”]
Just don’t copy and paste the source in your game :wink:

[quote=“dermetfan,post:14,topic:42439”]
This means:

  • download this
  • move it into the folder called “libs” in your core project
  • right-click the project and go to Properties -> Java Build Path -> Libraries
  • click “Add JARs…”
  • select libgdx-utils.jar from the libs folder

- optional: if you’d like to be able to click the class names with ctrl + click to see the source: download this, click the arrow left to libgdx-utils.jar (which is now in the list), double click “Source attachement” and select libgdx-utils-sources.jar (which you also have to put into your project)

  • click ok and ok again, done

Since you’re starting out with LibGDX, I’m also using this post to shamelessly point you to my tutorials ;D

#18

Tutorials are always welcome :smiley:

I have no issue actually creating a game being honest, I can create side scrolling platformer games without any graphics…only problem I have is how to organize all the code, Java is new to me as well, I have an ok understanding of it but far from expert. Just struggle with some things, once I learn how to properly use classes my code will be more efficient I hope :D, by properly use I mean appropriate use :stuck_out_tongue:

Watching the second episode atm, looking forward to the rest. You sound crazy nervous :stuck_out_tongue:

#19

Oh great, the organization and java knowledge will come over time :slight_smile: It’s basically just OO design.
Really? I actually wasn’t, it was just pretty new to me so I just had to concentrate very much ;D