Question Limit visible particles to graphics buffer count

I have a graphics buffer that contains positions and some additional data.
The length of this buffer can be different each frame.
I would like to limit the number of visible particles to the length of the buffer so it will only display as many particles as defined in the graphics buffer.
What is the best way to limit this?

I am currently setting their "Alive" state in the render context by comparing the particle id with the buffer length like this:



Is this actually the best solution?

 

If you have constant buffer size and you know that number of particles would never exceed this number, then hiding some particles by killing them sounds reasonable as you don't need any other thing than spawning that exact amount of particles at the beggining.

However if you allocate+dispose that buffer over and over and it's size jumps like

3 => 10 => 16 => 6 => 12

and you want the system to have that exact number of particles equal to buffer I find it easier to control this by introducing some add/remove system. When you need 3 more particles then previously you send spawn event and spawn that number of particles, if you need 3 less, then you kill that number in update. Still, I can't remember right now if I made it work this way, because of particle id - I am not sure if that was just index of particle or it was distributed when spawned, so you would need to test.

 

That sounds like an interesting solution. The buffer is mapped to enemy positions so its count will vary a lot over time.
But I also dont have a clue how to map the buffer to particles if I actually kill/spawn them.
Besides its easy to spawn particles via event bit how can I kill a specific number of particles via events.

 

You don't do it via events, but graph properties. You set count and then you do something like this in update:

alive = particleIdOrSomething < count

 

Oh I see thats what I was doing before moving the alive part into the render context.
Thanks for explaining the difference to me in the otehr thread btw. (https://forum.unity.com/threads/how...tted-without-killing-it.1019896/#post-8734521)

I guess I will see if this is a actually a performance bottleneck later and try out your suggestion if it is.
Would be great if vfx graph would be able to scale the capacity at runtime or discard particles early based on their id though.