Someone

for (L2Character character : list)
        {
            if (character != null && character instanceof L2MonsterInstance)
            {
                L2MonsterInstance mob = (L2MonsterInstance) character;
                Point3D posMob = mob.getWorldPosition();
                Point3D posMe = mob.getWorldPosition();
                if (posMob.distanceSquaredTo(posMe) < (80 * 80)
                        && mob.getHeading() - Math.atan2(posMe.getX() - posMob.getX(), posMe.getY() - posMob.getY()) < 40)
                {
                    
                }
            }
        }