public void use(){
		// use skill by type
		// add effects & element
		if(Game.PLAYER.reduceMana(requiredMana)){
		
		switch(type){
		case PROJECTILE: projectileAttack();
			break;
		case LASER: laserAttack();
			break;
		case IMPACT: impactAttack();
			break;
		case AURA: auraAttack();
			break;
		}
		
		}
		delta++;
		time++;
		if(delta >= Game.UPS) delta = 0;
	}