GameScreen.java

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Screen;
import com.badlogic.gdx.graphics.GL10;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.math.Matrix4;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Body;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;
import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer;
import com.badlogic.gdx.physics.box2d.CircleShape;
import com.badlogic.gdx.physics.box2d.Fixture;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.PolygonShape;
import com.badlogic.gdx.physics.box2d.World;


public class GameScreen implements Screen {

  private static final float WORLD_TO_BOX = 0.01f;
	private static final float BOX_TO_WORLD = 100f;
	private OrthographicCamera camera;
	private BodyDef groundDef;
	private Body groundBody;
	private BodyDef playerDef;
	private Body playerBody;
	
	private World world;
	private Box2DDebugRenderer debugRenderer;
	
	@Override
	public void dispose() {
		// TODO Auto-generated method stub

	}

	@Override
	public void hide() {
		// TODO Auto-generated method stub

	}

	@Override
	public void pause() {
		// TODO Auto-generated method stub

	}

	@Override
	public void render(float arg0) {
		Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
		
		camera.update();
		GL10 gl = Gdx.app.getGraphics().getGL10();
		camera.apply(gl);
		Matrix4 cameraCopy = camera.combined.cpy();
		debugRenderer.render(world, cameraCopy.scl(BOX_TO_WORLD));
		
		world.step(1/60f, 6, 2);
	}

	@Override
	public void resize(int arg0, int arg1) {
		// TODO Auto-generated method stub

	}

	@Override
	public void resume() {
		// TODO Auto-generated method stub

	}

	@Override
	public void show() {
		camera = new OrthographicCamera();
		camera.setToOrtho(false);
		world = new World(new Vector2(0, -10), true);
		debugRenderer = new Box2DDebugRenderer();
		
		groundDef = new BodyDef();
		groundDef.position.set(new Vector2((Gdx.graphics.getWidth() / 2) * WORLD_TO_BOX, 16f * WORLD_TO_BOX));
		groundBody = world.createBody(groundDef);
		PolygonShape groundShape = new PolygonShape();
		groundShape.setAsBox((Gdx.graphics.getWidth() / 2) * WORLD_TO_BOX, 16f * WORLD_TO_BOX);
		groundBody.createFixture(groundShape, 0f);
		groundShape.dispose();
		
		playerDef = new BodyDef();
		playerDef.type = BodyType.DynamicBody;
		playerDef.position.set(new Vector2(100 * WORLD_TO_BOX, 400 * WORLD_TO_BOX));
		playerBody = world.createBody(playerDef);
		
		PolygonShape playerShape = new PolygonShape();
		playerShape.setAsBox(50 * WORLD_TO_BOX, 50 * WORLD_TO_BOX);
		
		FixtureDef fixtureDef = new FixtureDef();
		fixtureDef.shape = playerShape;
		fixtureDef.density = 0.5f; 
		fixtureDef.friction = 0.4f;
		fixtureDef.restitution = 0.6f;
		
		Fixture fixture = playerBody.createFixture(fixtureDef);
		
		playerShape.dispose();
	}

}