Hi there everyone!
I am using Niagara to render the ground of my game, for that, I am spawning thousands of GPU particles in a grid like this 200x200 tile grid:
for a static particle, the performance up to the millions is pretty chill (top down camera so it will never show milions), but I need to control each particle and update them according to interactions. Simple example: interactions makes that single tile number change to number + 1 and the rest is intact.
As far as I have tested, the only way to do that is sending to the emitter the entire tile array with the new data and updating ALL particles
So my question is, what would be the optimal way to do that?
Breaking it in chunks like minecraft? Making smaller grids and spawning a lot of niagara systems to update only chunks
Leave it be with only one system and update them all
Another magic solution to just update a single particle that I donât know yet
TLDR: I need to update a single particle data, spawn single system with lots of particles or spawn multiple systems less particles?
I might be wrong but I donât think there is a standard to something like this. The best solution, I think would be to use the debug and optimization tools built into Niagara and in the Unreal Editor to see the impact of the various options available to you. Testing things out and seeing how they affect performance.
I havenât tested it, but my guess would be the following :
instead of using an array, use 2 RTs and update it through niagara stage which writes the RT1 = RT2 + some operation mask, then swap RT1 and RT2 assignment.
The when displaying the floor, spawn particles in a grid (so assign x and y values) then read the current RT1 at that grid value.
Since youâre working on the gpu, you want to avoid random access operations and instead write things in ways that are easy to batch and execute on gpu cores.
wouldnât using Render Textures limit too much the size of the grid because of resolution and memory issues and also limit the readable data to 4 floats per texture? Is it possible to sample an unfiltered pixel-perfect RT using niagara?
wouldnât using Render Textures limit too much the size of the grid
The size of the grid shouldnât be too much of a problem since weâre only looking at a 200x200 grid.
Niagara Arrayâs of this size will be difficult to maintain + access each field manually on the gpu is slow.
limit the readable data to 4 floats per texture?
This is a valid concern, but frankly, you can just add more textures if you need more information about the grid, typical games have thousands of textures loaded at once, I donât think using 4-5 small 200x200 textures for the ground is going to be much of an issue.
Is it possible to sample an unfiltered pixel-perfect RT using niagara?
I might be mistaken, but I believe if you sample on the center of the âpixelâ it always returns a non interpolated value, no matter how itâs actually being setup.
ohh sorry, I wasnât clear on that, the 200x200 is only an example, the real grid does not have a fixed size (a map of only 200 tiles would be too small for some parts of the game like a dungeon or a race track) I think I probably wouldnât go bigger than 1000x1000 but I am trying to make it scalable
