Fireball Rain Issues

By Will Fox

5/10/2023

Hey everyone!

This week, my group and I are still focusing on debugging our game since this is our final month of working on it. So, I decided to focus on our first boss, The Lich, who can be a little buggy at times. The Lich has a large scale attack called Fireball Rain that - you guessed it - rains fireballs. However, the fireballs can act a little goofy at times and can also be a little too much for the player.

So, what's up with the fireballs acting goofy? Well, each fireball raindrop is supposed to explode upon impact with the ground. However - and this is still an unsolved mystery - it doesn't work every time. About 50% of the fireballs that hit the ground actually explode while the other 50% just phase through the floor. This is obviously not intended and also makes the game easier than we want since the fireball explosion is what actually deals the damage. So, here is how I went about fixing it.

It was pretty simple, to be honest. Unreal Engines collision can be pretty funky sometimes and not work probably due to background processing and whatnot, so we have to come up with some ways to work around it.  I started by creating an actor that contained only a collision box volume and put it in the boss level. I then spread it out so that it covered the entire ground and was flush with it. Then, I went into the actors blueprint and got the "On Component Begin Overlap" node from the box collision component. From there, I used the "other actor" pin to determine if the thing overlapping the box was a fireball. The way I did this was simply by casting the actor to a fireball and if the cast failed, then the actor isn't a fireball. If it IS a fireball, it will call an event attached to the fireball that will spawn the fireball explosion and delete the actor. This is essentially a fail safe in case the fireball doesn't explode on initial impact with the ground. (It works well, by the way)

The other "must have" that needed to be added to the fireball is an impact zone. See, when you have a thousand fireballs raining from the sky, it's probably a good idea to at least let the player know where they are going to land. Again, this is a super easy thing to add. I just added a decal object to the fireball itself and stretched it out really long so that no matter how high above the ground the fireball is, the decal will always be projected onto the ground - aka, wherever the fireball is going to land. It's that easy! Plus, decals work with materials which are super fun to mess with and you can get some really neat effects so I strongly suggest playing with them. That's all for this week! Thanks for reading.