public void physic() {
		target = -1;
		if (airID > Value.airCastle) {
			for(int i=Screen.enemy.length-1;i>-1;i--) {
				if (Screen.enemy[i].inGame && Screen.enemy[i].isDead == false) {
						if (towerRange.intersects(Screen.enemy[i])) {
							target = i;
						}
				}
			}
		}
		
		if (target>=0 && coolDown == 0) {
			System.out.println(coolDown);
			Screen.enemy[target].health -= 1;
			coolDown = fireRate;
			if (Screen.enemy[target].health <=0) {
				Screen.enemy[target].isDead = true;
				Screen.enemy[target].enemyWalk = 0;
			}
		} else {
			coolDown -= 1;
			if (coolDown < 0) {
				coolDown = 0;
			}
		}
	}