Create() or Render() for creating instances

Question

I am learning Java, LibGDX, Box2D via the use of projects and tutorials, I am following a tutorial at the moment and I wanted to raise a question regarding the render() loop and the create() method.

So first create() always gets called first, then render(). If I am creating a bunch of instances such as:

public class Game implements ApplicationListener {

    World world;
    Box2DDebugRenderer debugRenderer;
    OrthographicCamera cam;
    BodyDef bodyDef;
    CircleShape circle;
    FixtureDef fixtureDef;

Should I use the new constructor here? or should I do that in the create() method?

@Override
public void create() {

    world = new World(new Vector2(0, -10), true);
    debugRenderer = new Box2DDebugRenderer();
    cam = new OrthographicCamera(800 / 2, 480 /2);
    bodyDef = new BodyDef();
    bodyDef.type = BodyType.DynamicBody;
    bodyDef.position.set(100, 300);
    circle = new CircleShape();
    circle.setRadius(6f);
    fixtureDef = new FixtureDef();

Or should I place it in the render() method?

I am a bit unsure which is best, doing it in render seems a bit naff, would that not cause the game to constantly create new instances every loop iteration resulting in performance issues?

Oh and meant to ask, when I am defining properties of an object, such as circle.setRadius(), create method would be the right place?

Answer 1

You should definetely not use a lot of new in your render loop. On desktop this isn't really a big problem, but on handheld devices this will invoke the garbage collector too often, which will result in a laggy gameplay.

Whether you do it in the attribute declaration, or in create doesn't make a big difference. Both is done just once in your application's lifecycle.