public void showGameScreen() {
gameScreen = new GameScreen(startScreen.getHeight(), startScreen.getWidth());
switchTheScreens(startScreen, gameScreen);
gameScreen.gameField.engine.process();
switchTheScreens(gameScreen, startScreen);
}
public void showStartScreen() {
startScreen = new StartScreen(this);
startScreen.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
startScreen.setResizable(false);
startScreen.setVisible(true);
}