Lag with WGLMakie

Specific Domains Visualization
8

You are of course right. That sleep call was just for illustration, I don’t plan to include that in my final code.

I timed updating the frame with:

using WGLMakie, JSServe
n = 200 # frame dimensions
img = Node(rand(UInt8, n, n))
function f() 
    img[] = rand(UInt8, n, n)
end
App() do session::Session
    image(img)
end

using BenchmarkTools
@btime f();

and got:

  # n = 100 -> 4.893 ms (10690 allocations: 586.30 KiB)
  # n = 200 -> 20.830 ms (40695 allocations: 2.07 MiB)
  # n = 400 -> 87.734 ms (160697 allocations: 8.10 MiB)
  # n = 800 -> 353.295 ms (640699 allocations: 28.87 MiB)

I also found out that the timings do not improve even if I use a function like this one:

function f(img, n) 
    for i in eachindex(img[])
        img[][i] = rand(UInt8)
    end
    img[] = img[]
end

Which reduces allocations. So most of the time is spent on data transfer? @sdanisch is this performance (about 200 x 200 pixels at 30 fps) right? Or am I missing something?