Apoca Force WAIFUs

Showing Unity’s NavMesh in-game

As part of a school assignment in the past year, my team and I created Apoca Force, a tower defense game where WAIFUs (World Apocalypse Intercepting Frontline Units) are deployed onto a battlefield to combat an undead horde. In this game, WAIFUs serve as the eponymous towers of the genre, but with a twist — by spending some resource, they can be moved after they are deployed.

To denote the areas that WAIFUs can walk on, we created an interface that highlighted walkable areas on the map when players decide to move their WAIFUs. This is what we ended up with:

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Dust to Dust

Organising your Unity Inspector fields with a dropdown filter

Over the past 4 months, my team and I have been working on a rogue-like hack-and-slash game for our school’s final year project called Dust to Dust. We have very high ambitions for the game, and we had never worked on projects as large of a scale as this. Of course, by doing that, the challenges we encountered got bigger as well. We had to keep track of many parameters in developing a role-playing video game, and quickly realised that the time taken to find Inspector properties in the project was getting longer and longer. Furthermore, the project was on a 15-week timeline, so every minute was valuable.

Hence, we needed an effective solution that would ease navigation in the project, and — like before — it became clear that we had to once again extend the Unity Editor to suit our needs.

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reCAPTCHA Meerkats
Image by Mike Birdy, from https://stocksnap.io/photo/animals-mammals-VJ91Z8LULN

Verifying Google reCAPTCHA v2 checkbox on PHP

17 July 2020: Updated the class provided in this article to make it easier to use.

For those of you using Google reCAPTCHA to weed out spam on your websites, here’s a code snippet for verifying the reCAPTCHA v2 tickbox response on the server-side using PHP.

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Ex-Terminator

Creating Reorderable Lists in the Unity Inspector

Update: Like this article? Then check out this other article on creating a dropdown filter for the Unity Inspector.

Over the last 5 months or so, me and my team have been involved in the development of a hybrid tower defense and RTS game called Ex-Terminator (click on the link to try it out, it’s free!) as part of a school project. During the course of developing the game, we quickly realised that, in order to allow us to have the flexibility to experiment with our level design, we had to experiment with a class in Unity called the ReorderableList.

If you’ve read some of the other articles here, you’d have noticed that we normally link Unity classes to its page on the Unity Scripting Reference. We didn’t do so here because there is no official documentation for it at the time this article was written. The ReorderableList class is filed under the namespace of UnityEditorInternal, which also doesn’t have official documentation. We’ve decided to write an article about it, however, because of how useful it is, and because of how little information there is currently about it online.

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Debugging with Beverage

Fixing an Apache cron log rotation error

If you manage a Unix-like server, every now and then, you might get an email from the server notifying you of important errors that occur in your server. Here’s one that I got earlier today from an Ubuntu 18.04 server of mine:

Cron <root@terresquall> test -x /usr/sbin/anacron || ( cd / && run-parts –report /etc/cron.daily )

/etc/cron.daily/logrotate:
error: error running shared postrotate script for ‘/var/log/apache2/*.log ‘
run-parts: /etc/cron.daily/logrotate exited with return code 1

Mail sent at 06:39

It’s never fun to receive server admin emails like this, because it means that your server has issues, but the message tends to be really ambiguous, so it’s really hard to figure out what the issue is. Obviously, I didn’t know what the issues were, so I had to do some research.

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Unity Editor Scene view

Checking the type of GameObject you are colliding with in Unity

In any given game, you are probably going to find dozens, if not hundreds of different objects colliding or intersecting with one another. Hence, one of the first things you learn in Unity is how to identify the type of object you have touched. These are the most common ways to do so among beginners:

void OnTriggerEnter(Collider other) {
     // If a GameObject has an "Enemy" tag, remove him. 
    if(other.tag == "Enemy") {
        Destroy(other.gameObject);
    }
}
void OnCollisionEnter(Collision collisionData) {
    // If a GameObject has an "Enemy" tag, remove him.
    if(collisionData.collider.tag == "Enemy") {
        Destroy(other.gameObject);
    }
} 

Essentially, the idea is checking whether the object we are colliding with or touching has been labelled with an Enemy tag, before we perform any action on the object.

Where tags are assigned.
Image source: Unity Manual: Tags

While it is simple and easy-to-understand, there are better ways of identifying objects we are colliding with.

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2D vector math hero - polar movement

Vector math for polar movement in 2D games (Unity)

Polar movement, i.e. moving objects at an angle, is something that people starting out in games programming often have trouble with. Coordinate systems are easy to understand, and so is moving things left and right or up and down; but what if you want to move at angles that are not parallel to an axis, like 30° upwards, or towards a target? How do you get a vector that represents that direction of movement?

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Collision Detection Modes in Unity

Collision detection modes in Unity’s Rigidbody component

It isn’t particularly difficult to set up physics-based movement for objects in Unity — simply add a Rigidbody component onto an object that has a Collider component, and you’ll have yourself an object that moves and collides realistically with other objects.

Discrete collision
This was set up in 10 minutes.

If you start having fast-moving objects however, you might start to see these objects tunnel through obstacles.

Discrete collision tunnelling
Just like quantum physics. Sort of.
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