3D Platformer GameDev Series – Weekly Blog #5: Creating a Killzone and Setting Up Player Respawn

Wowzas! It seems like the past few weeks have just been rolling by! Alas, after spending a little over a month on learning how to setup the player and controls, I can now shift my focus to the game environment and its effect on the player. This week, I will demonstrate how to create a “killzone” – and with it, the player respawn.

So first of all, what is a “killzone“? Well, actually, this term is something that the course instructor, James Doyle, uses to define an area which kills the player upon entering it. In most 3D platformers, the main killzone is the one which defines the area that is ‘out of bounds’ – the player is usually killed if they fall or manage to jump into it. Below (click image to enlarge), you can see how such a killzone is created, re-sized, and positioned in the Unity game scene:

KillzoneObjectInGameScene

In the image above, you may have noticed that we also created and attached a new C# script (called ‘KillPlayer’) onto the ‘KillZone’ empty object. Also, enabling ‘Is Trigger‘ on the box collider added component allows us to then use a function in the script called “OnTriggerEnter“. In this case, the function will be used to respawn the player (Note: The player respawn function is being called from the GameManager script):

KillPlayerScript

So you might be asking, “Why is the Respawn function being called from the GameManager script and not coded and executed locally in the KillPlayer script?” “Individual scripts should only handle their individual elements“, James Doyle answers in response. For this reason, the Respawn function is set up in the GameManager script since the GameManager script controls things at a broader/global level. Not only does it make the code/logic easier to perform and follow, this also makes sense since player respawn can be triggered by more than just the player entering a killzone (e.g.- player being killed by an enemy, etc..). Here, we begin setting up the player respawn function in the GameManager script:

SettingUpRespawn

One thing to note above is that the newly introduced ‘Awakefunction is called before the ‘Start’ function. To keep the code more logical to follow and process, the ‘Awake’ function is used here to setup the GameManager ‘instance‘ before any code in the ‘Start’ function is executed. This is done in order for the KillPlayer script to call the Respawn function. The same is done in the PlayerController script; that is, an awake function is used to setup the PlayerController as an instance of itself when the game starts. However, to actually make the player respawn using these instances, we also require a new function called a Coroutine. A coroutine can be used to execute code to perform a series of events, and more importantly, allows the ability to pause the execution of that code in between while other code is executed (i.e.- in the update functions):

RespawningWithCoroutine

It can be a bit difficult to explain and understand the code (and I won’t go any further than what’s described above), but essentially, using a coroutine this way can allow us to achieve the following player respawn effect in the game:

BasicPlayerRespawn

Next week, we will finish setting up the player respawn by fixing the camera and jumping animation glitch upon respawning (as you may or may not have noticed) as well as including a fade out transition during the respawning.

I hope you enjoyed reading this week’s blog post. Stay tuned for next week’s!

– Taklon

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