Changing the background color of a 3D Scene in Makie

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How can I make the background color of a (3D) scene contained within an LScene ? Including backgroundcolor=:black in the scenekw arg doesn’t seem to do it, nor does setting the attribute directly on lscene.scene . However, setting the attribute on scene seems to change lscene.scene.attributes[:background].

With a bit of fumbling around I found that if I set lscene.scene.clear=true then I get the effect that I’m looking for in particular which is a black background. However if I use a different color, e.g. lscene.scene.attributes[:background] = :purple then this kills performance; also it seems that once that attribute has been set it can’t be changed.

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@airpmb, was this issue solved?

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Not as yet. Though I do wonder if it’s related to some of the other performance issues on MacOS and wonder if anyone can duplicate it on another platform.

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I’m not sure what are you looking for but the following works just fine:

using GLMakie, ColorSchemes, Colors
# archimedean spiral
a, m, z₀ = 1, 2.1, 0
φ = LinRange(0,20π,500)
r = a*φ
x, y, z = r .* cos.(φ), r .* sin.(φ), m .* r .+ z₀;

set_theme!(backgroundcolor = :black)

fig = Figure(resolution = (500, 500))
ax = LScene(fig)
lines!(x, y, z, color = z, colormap = :viridis)
axis = ax.scene[OldAxis] # you can change more colors here!
axis[:ticks][:textcolor] = :white
fig[1, 1] = ax
#save("./results/FigBlack.png", fig, px_per_unit = 1)
fig

FigBlack
For more details you can take a look at this notebook.
https://nbviewer.jupyter.org/github/lazarusA/MakieNotebooks/blob/main/MakieBlack.ipynb

Best,
Lazaro

1 Like
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@lazarusA, do you know why the following is not enough to set the background color (at least in Win10, Julia Version 1.6.0-beta1.0):

lines(x, y, z, color = z, backgroundcolor = :black)
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To be honest, nope :smiley: (this also doesn’t work for me), but probably @jules knows ?

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That works for me as well but I think the issue I’m seeing has to do with wanting to have a different background color in a 3D LScene within a larger layout which has another background color. I probably should have made that part clearer in my post.

With regards to what I was observing about performance when I used :purple I just noticed something that I hadn’t before: it seems that the background in this case actually isn’t a constant purple but actually there is a very subtle color gradient towards black at the edges:

image
image1616×1658 246 KB

The really weird thing is that not every color causes this. I just picked purple at random; when I change that one word :purple in the code to :green instead, I see no gradient and no sluggishness:

image
image2024×2080 281 KB

Fortunately, as I mentioned in the original post, :black works in that it doesn’t kill performance, and I do get what I’m looking for which is something like this:

image
image2024×2080 267 KB

(in this last I also used the set_theme! as suggested to get the grey background outside of the 3D view).

Anyhow to be clear, for now I have the output I’m looking for but I really can’t say I understand why it works, and in particularly why lscene.scene.clear=true is important, and why I sometimes see the gradient and performance behavior based just on what color I specify in the scenekw args in the LScene call.

Is someone aware of a similar example combining controls on a different-color background, with a 3D view (subscene? LScene?), all using the newer layout API?

I’ll try to get to making a MWE and post it so others can explore this if they want, but unless maybe something about the gradient makes one of you Makie experts say ‘aha’, I won’t be too sad about going forward with what I have.

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The gradient is an SSAO artifact I think, and that’s also what drags down performance. At least @ffreyer said something to that effect if I’m not mistaken, and he’s the one who implemented it and currently has a PR active to fix this (and disable SSAO by default)

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Oh, I messed up a bit there.

SSAO uses a normal buffer which gets cleared to (1,1,1) at the start of the drawing process. I use that clear value to discard pixels that have no geometry. What I overlooked is that the background color again clears that buffer, so if you set it to something other than white the ssao pipeline thinks there is geometry there. I pushed a fix in the pr that allows you to skip the whole SSAO pipeline.

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