Group actors into groups and remove them en masse

Development Programming & Scripting C++
1

Hi, I have procedurally generated world and I need to delete actors when they are too far away from player. My world is divided into invisible grid and I want to remove all the actors in that grid at once. How can I group them and remove them all at once?

2

This isn’t really my field of expertise, but I know that you can combine different levels using World Composition. You can also load/unload different parts of the composition, so I think this is what you are looking for.

3

I guess you mean Level Streaming, which I cannot use because I procedurally build my world at runtime, so I cannot use those functions.

Also, I already have mathematical mechanics for loading/unloading, all I need is a way to utilize them.

4

AFAIK, you have to remove each one individually. I have a spawn manager that checks for any players in the area, if none, goes through that list and remove them.

5

Yeah I expected they are removed one by one from some kind of list, but I need more than that, I need specific way I can store large amount of actors, classify them and destroy them. Some code or link for further searching, stuff like that.

6

Umm I still need the answers, please, somone…

7

Nothing?! I need the answers, at least some…

8

Store large amount of actors

Load actors into following arrays:




TArray<AActor*> ActorGroup1
TArray<AActor*> ActorGroup2
etc

for (AActor* a : ActorGroup1)
{
a.destroy()
}

Repeat.

9

Oh so I can use containers for storing pointers to all the actors I need?! Can I use TMultiMap for storing them in specific groups and then removing one key-group when needed?

10

I do not mean to offend, but this is a basic concept in programming with C++.

I have not used TMultMap. Beware that some of these containers may not be supported in Blueprints.

11

I’d like to mention that mass deleting actors will cause an fps stutter (probably a big one) if you are doing it from the main thread.

12

No offense taken, I am new at C++ and I dont intend to use Blueprints.

And is there a way to do it without significant performance drop? Or do I have to learn multi-threading? I am definitelly going to do multi-threading, but it seems like high-level stuff to learn so I have not yet touched that concept.

13

You’re better of just setting up proper culling. Another option would be to use prefabs. This will make your destroy list a lot smaller. The list itself would be TArray (Actor Object Reference).

14

I aim to have procedurally generated world that generates and destroys around player as they move, I doubt culling will be enough, as I would be left with thousands upon thousands of objects. Also what is the difference between C++ Actor class and prefab?

15

A prefab is a class containing multiple actors/components as a single prop. An example would be a building or a group of buildings, its interior décor/props, lighting, reflection spheres etc.