Login - hash problem

Hi, i have a login system for my game on unity, people need to register at the website then they can log into the game, on my website when they register the password comes to a salt hash in the db, so iam wondering how can this php script (password) convert what they type in game to a salt hash

 <?php
         $user_name = $_REQUEST['user_name'];
         $password = $_REQUEST['password'];
         
         $database = mysql_connect('localhost', '*******', '******') or die('Could not connect: ' . mysql_error());
         mysql_select_db('******') or die('Could not select database');
     
         $query="SELECT * FROM users WHERE user_name='".mysql_real_escape_string($user_name)."'AND password='".$password."'"; 
         $result=mysql_query($query);
     
         if (mysql_num_rows($result)>0) 
             echo "right";
         else
             echo "wrong";
     ?>
 

iam sorry for my english and i hope you understand and this is a part of my login script:

 string login_URL = loginURL + "?user_name=" + userNamez + "&password=" + passWordz;