public void planNextStep(double s_elapsed) {
    for (Scenery scenery : sceneries) {
      scenery.planNextAction(s_elapsed);
    }
    for (Powerup powerup : powerups) {
      powerup.planNextAction(s_elapsed);
    }
    for (Shot shot : shots) {
      shot.planNextAction(s_elapsed);
    }
    for (ProximityBomb bomb : bombs) {
      bomb.planNextAction(s_elapsed);
    }
    for (Robot robot : robots) {
      robot.planNextAction(s_elapsed);
    }
    for (Pyro pyro : pyros) {
      pyro.planNextAction(s_elapsed);
    }
    for (MapObject object : misc_objects) {
      object.planNextAction(s_elapsed);
    }
  }