public class MyWorld extends World
{
    public int wave;
    private int wave_delay0 = 200;
    private int wave_delay1 = 500;
    private int wave_delay2 = 100;
    private int wave_delay3 = 100;
    private int wave_delay4 = 100;
    private int wave_delay5 = 100;
    private int wave_delay6 = 100;
    
    public MyWorld()
    {    
        super(800, 600, 1); 
        this.addObject(new Player(),550,50);
        wave = 0;
        this.addObject(new IntroText(),getWidth()/2, getHeight()/2);
    }
    public void act()
    {
       wave();          
    }
    public void wave()
    {
        int spawn_x = Greenfoot.getRandomNumber(750);
        int spawn_y = Greenfoot.getRandomNumber(550);
        
       
        switch (wave) 
        {
            case 0:
            wave_delay0 -= 1;
                if(wave_delay0 == 0){
                    wave++;
            
                }
            break;
            case 1:
            wave_delay1 -= 1;
            for (int i = 0; i < 3; i++) 
            {
               this.addObject(new Enemy(),spawn_x,spawn_y);               
            }
                if(wave_delay1 == 0){
                    wave++;
            
                }
            break;
        }
       
    }
}