Building Browsergames: Swapping Weapons (PHP)

It was a close race, but in the end the results of our poll on whether users should dual wield their weapons or have to toggle which one was active have been decided: users will toggle which weapon is currently active. Today, we’re going to be implementing that functionality.

The ’swap weapon’ page is a fairly simple one – all we need is a template and some code to handle it(we even wrote most of it earlier, when we built our weapons shop). We’ll start off with the template, and call it equipment.tpl:

<html>
<head>
	<title>Equipment Management</title>
</head>
<body>
	<h3>Current Equipment:</h3>
	<p><a href='index.php'>Back to main</a></p>
	<ul>
		<li>
			Primary Hand:
			{if $phand ne ''}
				{$phand}
				<form action='weapon-shop.php' method='post'>
					<input type='hidden' name='sell' value='phand' />
					<input type='submit' value='Sell' />
				</form>
			{else}
				None
			{/if}
		</li>
		<li>
			Secondary Hand:
			{if $shand ne ''}
				{$shand}
				<form action='weapon-shop.php' method='post'>
					<input type='hidden' name='sell' value='shand' />
					<input type='submit' value='Sell' />
				</form>
			{else}
				None
			{/if}
		</li>
	</ul>
	<p>
		<form action='equipment.php' method='post'>
			<input type='submit' value='Swap' name='swap' />
		</form>
	</p>
</body>
</html>

This template is relatively simple, and essentially just the top parts of the weapon shop’s template – we even left in the ‘Sell’ buttons, so that users can sell their equipment straight from their equipment page. We have to make sure that the ’swap’ button has a ‘name’ attribute – that way we can check $_POST later to see if it was clicked. Next we’ll build equipment.php, which is responsible for retrieving the current weapons a user is using, and displaying this template:

<?php
 
require_once 'smarty.php';
 
session_start();
 
require_once 'config.php';		// our database settings
$conn = mysql_connect($dbhost,$dbuser,$dbpass)
	or die('Error connecting to mysql');
mysql_select_db($dbname);
// retrieve player's ID
$query = sprintf("SELECT id FROM users WHERE UPPER(username) = UPPER('%s')",
			mysql_real_escape_string($_SESSION['username']));
$result = mysql_query($query);
list($userID) = mysql_fetch_row($result);
 
require_once 'stats.php';	// player stats
$phand = getStat('phand',$userID);
$shand = getStat('shand',$userID);
$phand_query = sprintf("SELECT name FROM items WHERE id = %s",
				mysql_real_escape_string($phand));
$result = mysql_query($phand_query);
if($result) {
	list($phand_name) = mysql_fetch_row($result);
	$smarty->assign('phand',$phand_name);
}
$shand_query = sprintf("SELECT name FROM items WHERE id = %s",
				mysql_real_escape_string($shand));
$result = mysql_query($shand_query);
if($result) {
	list($shand_name) = mysql_fetch_row($result);
	$smarty->assign('shand',$shand_name);
}
$smarty->display('equipment.tpl');
 
?>

Essentially, all that we’re going to be adding on to this code is handling for a POST request; if something is POSTed to this page, we swap the user’s current weapons. The code is fairly simple, as you can see:

if($_POST) {
	setStat('phand',$userID,$shand);
	setStat('shand',$userID,$phand);
	$temp = $shand;
	$shand = $phand;	
	$phand = $temp;
}

And that’s all there is to it! We just add another link to our index page:

19	<p><a href='equipment.php'>Equipment Management</a></p>

And we’re finished! Here’s the code for our template:

<html>
<head>
	<title>Equipment Management</title>
</head>
<body>
	<h3>Current Equipment:</h3>
	<p><a href='index.php'>Back to main</a></p>
	<ul>
		<li>
			Primary Hand:
			{if $phand ne ''}
				{$phand}
				<form action='weapon-shop.php' method='post'>
					<input type='hidden' name='sell' value='phand' />
					<input type='submit' value='Sell' />
				</form>
			{else}
				None
			{/if}
		</li>
		<li>
			Secondary Hand:
			{if $shand ne ''}
				{$shand}
				<form action='weapon-shop.php' method='post'>
					<input type='hidden' name='sell' value='shand' />
					<input type='submit' value='Sell' />
				</form>
			{else}
				None
			{/if}
		</li>
	</ul>
	<p>
		<form action='equipment.php' method='post'>
			<input type='submit' value='Swap' name='swap' />
		</form>
	</p>
</body>
</html>

And here’s the code for the file that handles the functionality behind the template:

<?php
 
require_once 'smarty.php';
 
session_start();
 
require_once 'config.php';		// our database settings
$conn = mysql_connect($dbhost,$dbuser,$dbpass)
	or die('Error connecting to mysql');
mysql_select_db($dbname);
// retrieve player's ID
$query = sprintf("SELECT id FROM users WHERE UPPER(username) = UPPER('%s')",
			mysql_real_escape_string($_SESSION['username']));
$result = mysql_query($query);
list($userID) = mysql_fetch_row($result);
 
require_once 'stats.php';	// player stats
$phand = getStat('phand',$userID);
$shand = getStat('shand',$userID);
if($_POST) {
	setStat('phand',$userID,$shand);
	setStat('shand',$userID,$phand);
	$temp = $shand;
	$shand = $phand;	
	$phand = $temp;
}
$phand_query = sprintf("SELECT name FROM items WHERE id = %s",
				mysql_real_escape_string($phand));
$result = mysql_query($phand_query);
if($result) {
	list($phand_name) = mysql_fetch_row($result);
	$smarty->assign('phand',$phand_name);
}
$shand_query = sprintf("SELECT name FROM items WHERE id = %s",
				mysql_real_escape_string($shand));
$result = mysql_query($shand_query);
if($result) {
	list($shand_name) = mysql_fetch_row($result);
	$smarty->assign('shand',$shand_name);
}
$smarty->display('equipment.tpl');
 
?>

Luke is the primary editor of Building Browsergames, and has written a large portion of the articles that you read here. He generally has no idea what to say when asked to write about himself in the third person.

Tuesday, August 19th, 2008 buildingbrowsergames, code, php

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Building Browsergames is a blog about browsergames(also known as PBBG's). It's geared towards the beginner to intermediate developer who has an interest in building their own browsergame.

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