public void update(float delta) {
		world.step(1 / 30f, 8, 3);

		if (flap && flapCount != 1) { // only start flapping after intro.
			flappyBird.setLinearVelocity(0, 1.5f);
			flappyBird.setTransform(flappyBird.getPosition().x, flappyBird.getPosition().y, .3f);
			flap = false;
			Jukebox.play("flap");
		}
		
		if(myContactListener.getPlayerCollision()) {
			playerCollidedWithWorld  = true;
		}

		if(!playerCollidedWithWorld) {
			dipFlappyBirdToGround();			
			movePipes();
			centerFlappyBird();
		}
		else {flappyBird.setAngularVelocity(0);}
	}