Hi. I'm John.

Sometimes I make games. Sometimes I make websites. This is my blog.

Tag Archives: how-to


How To Fix Unity3d Transparent Shader Not Respecting Z-Index

Before and After: Unity3d Transparent Shaders Respecting Z-Index

Before and after. Bright colours used to demonstrate effect of fix.

The fact that, by default, the transparent shaders in Unity3d do not work well behind or in front of objects has been a problem for years. Here’s an easy fix that might solve it for you.

Steps

  1. Make a duplicate of the transparent shader in question. For me, this was Unlit – Transparent Tint. I found it by searching my Project window in the Unity3d editor for “Unlit”.
  2. Edit the new shader in a text editor (default: MonoDevelop).
  3. On line 1, change the name of your shader to something you’ll remember. This is where it will be in your shader selection dropdown in the editor.
  4. Under the SubShader section, add +1 to the item in the “Queue” section. For me, this became “Queue” = “Transparent+1”.
  5. Save your shader.
  6. Apply it to your game object.

That’s it! With any luck, the object with your transparent shader should now appear in front of other game objects which also use a transparent shader.

Develop Locally With Linux, Apache, MySQL, and PHP

If you’d like to develop PHP and MySQL web apps in Linux but you’re not sure how to get started then feel free to follow along with this blog post. For the most part, installation and configuration is simple and straightforward.

Though this article is directed toward users of Mandriva Linux (my Linux distribution of choice for a desktop / web-development PC), the same instructions can apply to many of the different Linux distributions including Fedora, Red Hat Enterprise Linux, Ubuntu, and Eeebuntu. For a huge list and up-to-date news of Linux distributions available to you, take a look at the Distrowatch news site.

The easiest way to install all of the software in the LAMP stack (Linux Apache MySQL and PHP) quickly is to do it using the command-line (also known as the console). Since many new users are uncomfortable with the command-line, feel free to do all of these installations graphically using the software installer from your respective distribution.

If you’d like to proceed using the graphical installer built into Mandriva Linux, use the “Install & Remove Software” icon located in the main menu.

To install apache, mysql, and php using the Mandriva command-line, follow these instructions:

  • Open up a terminal by clicking on the Mandriva star and clicking on Terminal
  • Type “su” and press enter (this will log you in as the administrator or “root” user)
  • Enter your root password
  • Type “urpmi apache php mysql phpmyadmin nano”
  • If asked which version of apache, select a stable version to install (likely the first choice)
  • If asked which version of php, select the apache module version (not CGI or CLI)
  • If asked for permission to install extra software that is required for proper operation of the LAMP stack, select “yes” and proceed

Once the software has been installed, you should be able to open up Firefox and navigate to http://localhost . This should bring up a screen that says “It works!”, meaning that apache has been properly installed.

For reference, Mandriva Linux puts your web files in the directory /var/www/html . Straight away you may not be able to access those folders with your regular user so feel free to change the permissions of the directory recursively by using the command

chown -R yourusername:yourusername /var/www/html

Note that this operation is definitely not secure if you plan on actually hosting your website on the live Internet using this computer, but for local development you should be okay. :) To learn more about file and directory permissions in Linux, take a look at the official documentation.

Before you are able to access your databases through phpmyadmin, you will need to set your MySQL root password using the following command (being sure to change NEWPASSWORD to a password of your choice):

 mysqladmin -u root password NEWPASSWORD

Using Firefox (or whatever browser you normally use) navigate to http://localhost/phpmyadmin . Log into MySQL with your “root” user and the password you just entered into the command-line. This should give you access to your MySQL databases. For more information on how to use phpmyadmin, take a look at the official website.

Let’s create a small Hello World PHP web application by navigating to our web directory and creating it. Use the following commands to achieve this:

cd /var/www/html
nano test.php

In the editor screen that appears, enter

<?php echo "Hello World!"; ?>

Press CTRL-X and save the file before quitting. You should now be able to navigate to http://localhost/test.php and see your hello world application :)

Hopefully this has given you enough information to get you up and running. Please feel free to post comments if you’ve run into problems and hopefully I or another person in the community will be able to help you out.

Have fun with PHP on Linux!

HTML Input Forms – Sending in an array in PHP

Arrays? Who needs ’em?

If you’re into developing websites chances are there will be sometime during your life/career when you’ll need to have users enter data into a HTML form but you have no idea how many of a certain variable they’re going to be sending in or how much data they’re going to fill in of the same type.

An example would be a HTML form that has three input boxes, one for each of your friend’s names (first and last). You are able to enter between 1 and 3 friends into the boxes. For such an example your HTML form may look something like this:

<form method="post" action="">
    <p>Enter your friend's names (first, last):</p>
    <input maxlength="30" name="friend1" size="30" type="text" />
    <input maxlength="30" name="friend2" size="30" type="text" />
    <input maxlength="30" name="friend3" size="30" type="text" />
    <input type="submit" value="Submit" />
</form>

That all looks fairly normal. Keep in mind this is a simple example. But, what about if you’ve got the option to enter 10 friends. What about 20? You might have to re-work your form if you want to enter 20 friends. Any more than 10 and you might want to look at alternatives like importing from XML or CSV.

Let’s say you’ve got the option to enter up to 10 names. Your increasingly ugly form would then look like this:

<form method="post" action="">   <p>Enter your friend's names (first, last):</p>   <input maxlength="30" name="friend1" size="30" type="text" />   <input maxlength="30" name="friend2" size="30" type="text" />   <input maxlength="30" name="friend3" size="30" type="text" />   <input maxlength="30" name="friend4" size="30" type="text" />   <input maxlength="30" name="friend5" size="30" type="text" />   <input maxlength="30" name="friend6" size="30" type="text" />   <input maxlength="30" name="friend7" size="30" type="text" />   <input maxlength="30" name="friend8" size="30" type="text" />   <input maxlength="30" name="friend9" size="30" type="text" />   <input maxlength="30" name="friend10" size="30" type="text" />   <input type="submit" value="Submit" /> </form>

When you submit this form then you’ve got to check each input box to first ensure they entered a variable and then check to see what that variable is. With so many input boxes to check from it becomes a repetitive and arduous task.

Example PHP code:

// Good God.. okay let's start this horrible task
if ($_POST['friend1']) {
    doSomething($_POST['friend1']);
} else {
    complain();
}
if ($_POST['friend2']) {
    ...
} else {
    complain();
}
if ($_POST['friend3']) {
    ...
} else {
    ...
}
...
...
// There's got to be a better way!

Save time with arrays.

Using PHP and HTML, the HTML form code can be re-written to have the server create a PHP array of your friends’ names, like this:

HTML Form:

<form method="post" action="">
    <p>Enter your friend's names (first, last):</p>
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input maxlength="30" name="friend[]" size="30" type="text" />
    <input type="submit" value="Submit" />
</form>

Server-Side PHP:

// Loop through the friend array
foreach ($_POST['friend'] as $value) {
    // Do something with each valid friend entry ...
    if ($value) {
        echo $value."<br />";
        ...
    }
}

Let’s walk through that PHP code.

It’s fairly simple. We walk through the php $_POST[‘friend’] array that we retrieved from the HTML form using foreach and for all of the entries on the form that the user typed in we do something with (in this case we simply echo them to the screen).

This simple foreach loop will save you time and the good part is that you can have any number of friends on your form (I’m sure there’s a maximum somewhere though.. 256 maybe?) and this block of code will still work.

In the next article I’ll show you how to do the same thing with ColdFusion.

PHP Tricks: Eliminate any unwanted characters from a string

Hi all.

I’ve been looking for a handy/graceful way to do this for a while and I thought I’d share this little php trick with you in the hopes that it’ll save you some time if you ever need it. If anyone reading this can quickly convert this example into other languages such as perl, coldfusion, ruby, c, c++ please be my guest and post it as a comment or as a trackback to this blog.

What I wanted to do

I wanted to scrub any characters out of a string that were not alphanumeric. That is, not “a” to “z” and “0” to “9”. Thankfully, PHP has extensive regular expressions support so that’s what we’ll use.

Why

I needed to store files uploaded through PHP on my Linux machine using a filename chosen by the user. A web site I’m working on requires users to upload media (images, video, music, et. al) and in order to save the files on the hard disk. This functionality prevents code failure by making the filename valid in UNIX filesystems.

The Code

/**
 * Converts a string to a valid UNIX filename.
 * @param $string The filename to be converted
 * @return $string The filename converted
 */
function convert_to_filename ($string) {

  // Replace spaces with underscores and makes the string lowercase
  $string = str_replace (" ", "_", $string);
  $string = str_replace ("..", ".", $string);
  $string = strtolower ($string);

  // Match any character that is not in our whitelist
  preg_match_all ("/[^0-9^a-z^_^.]/", $string, $matches);

  // Loop through the matches with foreach
  foreach ($matches[0] as $value) {
    $string = str_replace($value, "", $string);
  }
  return $string;
}

Usage

Simply call the convert_to_filename function and pass the filename/string along. For example:

$valid_filename = convert_to_filename ($original_filename);

How it works

Almost the entire function is self-explanatory as long as you have a bit of experience with PHP. The part that does the actual deed may need some explanation, however. Especially if you’re relatively new to regular expressions. The part that strips the bad characters from the filename string is started first by this line, which uses a regular expression to make an array called $matches of all of the characters that are NOT a-z, 0-9, a period, or an underscore:

preg_match_all ("/[^0-9^a-z^_^.]/", $string, $matches);

Then, we simply walk through the array replacing the offending character with nothing using the PHP function str_replace.

Functions Used

The functions/constructs used in this article are

Source Control – svn + ssh (subversion to the rescue!)

There comes a point in any developer’s life where he/she must work with one or more people on the same project. What’s the correct procedure? How is this done? There are a number of different ways. Some good, some bad.

The Bad: You may have a method in place where only one person can be working on a file at one time. You have to notify the other developers that the file is free when you’re done with it. They download the latest copy every time and so do you so as to not overwrite the work that was just completed.

Some of you may say “Well, why is this bad? We’ve done this for months! It’s worked out pretty well so far!” There are a number of different answers to this question, which I’m going to deal with right now.

This is a bad method because time is money and this method is much, much slower. What is a programmer to do while he or she is waiting for the file to be free for editing? Read blogs?

Time is money.

If the company had source control, both programmers could essentially be working on the same file at the same time. I say essentially because technically they both have their own versions of it and the source control program (Subversion is the one I would like to write about today) will merge their changes together intelligently. Oh wait, this isn’t good. Now you won’t have time to read my blog because you’ll be working!

The second reason the “one person, one file, one time” method is bad is because it’s extremely risky for accidentally deleting work and wasting hours of productivity. As a developer, you should be constantly using and building work methods that prevent failure at any level you are involved with.

How would you feel if you worked on a function for two hours, then because someone overwrote the file with their copy all your work was lost? The reverse is also true: How would you feel if when you saved your work you accidentally overwrote a day’s worth of work and changes?

Time is money. Again.

“But before you save your file you can make a backup of the original file!” I hear you saying, way in the back. Of course you could, but how far do you want to take that methodology? Will you remember every time? Will everyone who works on the project remember, every time? What if it’s a one-line fix? “Oh, I’ll just log in quickly and fix that typo.” and the like are sentences that run shivers down my spine when thinking about using this method.

So the person logs in and fixes the typo. Because it was a small fix, they never checked to see if anyone was working on the file. So now we’ve got two changes that need to be merged somehow. I’m sure that person will be wondering the next day why the typo has reappeared after you save your file!

Okay. So what’s the solution then, smarty-pants?

The good: The solution is source control. It’s not new. It’s been tested and proven multiple times in the computing industry and there are some big players that use it. There are a multitude of different kinds that do some different things, but to the layman the simplest way to look at it is to use a common source control program called Subversion. Everyone’s heard of it, a ton of people use it. Nerds of different flavors will tell you there are better ones out there, and that may be true, but Subversion works. For a lot of folks.

The concept is simple: A project is set up in the Subversion software. Two programmers “check out” (think of checking out at a grocery store) a copy of the project on their computer or development server and work completely independently.

Programmer “Jane” and “Jack” are both working on the same project. Jane is building a module not related to Jack but in a few cases they may modify the same files. That’s no cause for concern, deliberation, or communication. They happily keep on working until their particular task is complete.

Jane finishes first and “checks in” her work by “committing” her work to the Subversion server. Everything goes as planned and her work is then “committed” to the main project files. Jack finishes his work a few minutes later and attempts to check in his work. Uh-oh! Jack’s copy of the project is slightly out-of-date! No big deal, he issues the “svn update” command and all of the files Jane edited are updated on Jack’s computer. Any changes to the files that they both worked on are merged automatically.

After he has updated his copy of the project he commits his files and goes home for the day.

Wow! Sounds great. But what happens if Jack deletes parts of the source code that Jane edited?

This sort of thing is called a conflict. They’re pretty rare and in most cases you can resolve the conflict in a few minutes. When you edit a file that is marked “in conflict” by Subversion, it shows the added and removed portions. You can make adjustments based on which is correct and issue the “svn resolve” command to consider the issue resolved then commit the correct version.

Cool beans. How do I start?

First, you install Subversion on your server. Programmers will connect to this machine, “check out” a copy of the project, and begin work. In most cases, installing Subversion takes less than 10 minutes. You should check with your particular Operating System documentation to see how to install Subversion, but in Mandriva Linux you can do it through the command-line with this command (logged in as root):

# urpmi subversion

After installing Subversion, you will need to pick a spot on your hard drive where you want your project files to be located. For me, that’s almost always /home/svn. Change directory to your project directory and type:

# svnadmin create <projectname>

This will create a directory and place the important Subversion bits inside it for this all to function. Make sure the directory (and all subdirectories) are writeable by the group of users that will be working on the project by first first changing the ownership to a particular user and group with this command (run as root):

# chown -R user:devgroup <projectname>

This command makes the project directory and any directory inside of it owned by user and associated with the devgroup group. After this you will need to set the permissions on the directory so that the devgroup has read, write, and execute access to this directory. We do that by executing this command (run as root):

# chmod -R 775 <projectname>

Great! Our project is ready to roll. Note that this assumes you have ssh enabled on this server (very likely by in Linux, FreeBSD, and in fact most others *nix variants).

Next, we’ll need to check out a copy of our project. Stay tuned for that tutorial, coming soon!