private void GenerateEnemies(){
        int ns = RandomEngine.randInt(2,width*height/4);
        Enemies = new ArrayList();
        int t;
        int rand;
        Enemy e;
        float x,y;
        float unitScale = constant.getFloatConstant("unitScale");
        for(int i=0;i<ns;++i){
            rand = RandomEngine.randInt(0, 10000);
            x = RandomEngine.randInt(3, width-3);
            y = RandomEngine.randInt(3, height-3);
            if(rand%200 == 0) t=2;
            else if(rand%5 == 0) t=1;
            else t=0;
            switch(t){
                case 0: e = new Worm(unitScale); break;
                case 1: e = new Ghost(unitScale); break;
                case 2: e = new Boss1(unitScale); break;
                default: e = new Worm(unitScale); break;
            }
            e.setPosition(x, y);
            Enemies.add(e);
       }
    }