Contours + Observable often disappear and leave blank axis (WebGL)

[aplavin]

When using an observable in contour, and updating the observable, the plotted contours often (not always) disappear – leaving a blank axis.

MWE short script:

using WGLMakie

fig = Figure()

shiftobs = Observable((0., 0.))
data0 = rand(100, 100)
data = @lift circshift(data0, round.(Int, $shiftobs))

contour(fig[1,1], data)

display(fig)

for i in 1:10
    shiftobs[] = (i, i)
    sleep(0.2)
end

Video recording of me running this script twice. First run goes fine for a few iterations and then blanks, second run it blanks almost immediately:

Screen.Recording.2024-04-17.at.08.29.16.mov

The exact same code works using GLMakie instead of WGL.

• are you running newest version (version from docs) ? Yes
• can you reproduce the bug with a fresh environment ? (]activate --temp; add Makie) Yes
• What platform + GPU are you on? Macbook M2, running WGLMakie in VSCode or Pluto with the same results