scale! is inconsistently applied to campixel and background axis for LScene

[moyner]

• [Makie 0.24.8 / GLMakie 0.13.8] what version of Makie are you running? (]st -m Makie)
• [Yes] can you reproduce the bug with a fresh environment ? (]activate --temp; add Makie)
• [Tested on macOS and Windows 11] What platform + GPU are you on?
• [GLMakie] Which backend are you using? (GLMakie, CairoMakie, WGLMakie, RPRMakie)
• [] Please provide an minimal example of the failing code. If the problem is with the visualization, please provide a picture or video of it.

There seems to be a couple of issues with the scaling for LScene. I could be doing this the wrong way, though, but I have some workflows where scaling is used and this popped up. Two examples:

Scaling of background mesh

using GLMakie
using GLMakie.GeometryBasics

c = Cylinder(Point3f(-1, 0, 0), Point3f(0, 0, 1), 0.3f0)
fig, ax, plt = mesh(c)
ax2 = LScene(fig[1, 2])
mesh!(ax2, c)
scale!(ax2.scene, 1.0, 1.0, 3.0)
fig

Campixel subscene

c = Cylinder(Point3f(-1, 0, 0), Point3f(0, 0, 1), 0.3f0)
fig, ax1, plt = mesh(c)
ax2 = LScene(fig[1, 2])
mesh!(ax2, c)
for ax in [ax1, ax2]
    bgscene = Scene(ax.scene)
    campixel!(bgscene)
    w, h = size(bgscene) # get the size of the scene in pixels
    # this draws a line at the scene window boundary
    bg = [sin(i/w) + cos(j/h) for i in 1:w, j in 1:h]
    bg_plt = image!(bgscene, [0.5*i/w + (1.0 - (j/h)^1.5) for i in 1:w, j in 1:h],
        colormap = :viridis,
        colorrange = (minimum(bg), maximum(bg))
    )
    translate!(bg_plt, 0, 0, -10000)
end
# Every so slightly scale axis2
scale!(ax2.scene, 1.0, 1.0, 1.0001)
fig

In this case, the background disappears whenever scaling is used. Re-drawing it after scaling does not seem to help.

[ffreyer]

This is just how transformations are composed across scenes and plots. Each level calculates a model matrix from scale!(), traslate!() and rotate!(). They then apply starting from the plot to the root scene. Here you have:

fig.scene - identity transformation
  ax2.blockscene - identity transformation
    ax2.scene - z scale
      bgscene - identity transformation
        bg_plt - z translation

which means you apply (without the identities):

scalematrix(Vec3f1, 1, 1.0001)) * (translationmatrix(0, 0, -10_000) * vertices)

This gets you outside the clipping limits of -10_000 .. 10_000.

[moyner]

Thanks a lot! This explanation fixes my background issues if I just divide the translation by the known z scaling. I think the old Axis3D is still acting strangely when scaling and translating, or is there something I have missed there?

[ffreyer]

You can also move the background scene one level higher, to ax2.blockscene, or create the image plot with transformation = :nothing to avoid inheriting from the scene.

I think the old Axis3D is still acting strangely when scaling and translating, or is there something I have missed there?

The old Axis3D isn't set up to work with scene transformations. At the moment this is what happens:

f,a,p = scatter(rand(Point3f, 10))
display(f)

# scales the scatter plot and the visuals of the axis by 2
# limits do not update here, so the "0.5" tick is now shown at 2*0.5, for example
scale!(a.scene, 2,2,2)

# triggers a limit reset
# limits do consider transformations, so ticks are build for 2 * rand(Point3f, 10)
# scene transformations also still apply, so the axis ends up placing ticks for
# 2 * rand(Point3f, 10) in a 2 * (2 * rand(Point3f, 10)) box
scatter!(a, rand(Point3f, 10)) # causes a limit reset

This is probably fairly easy to fix by adding transformation = :nothing here:

Makie.jl/Makie/src/basic_recipes/axis.jl

Lines 61 to 100 in 996f586

	return Attributes(
	visible = true,
	showticks = (true, true, true),
	showaxis = (true, true, true),
	showgrid = (true, true, true),
	scale = Vec3f(1),
	padding = 0.1,
	inspectable = false,
	clip_planes = Plane3f[],
	fonts = theme(scene, :fonts),
	names = Attributes(
	axisnames = ("x", "y", "z"),
	textcolor = (:black, :black, :black),
	rotation = axisnames_rotation3d,
	fontsize = (6.0, 6.0, 6.0),
	align = axisnames_align3d,
	font = lift(to_3tuple, theme(scene, :font)),
	gap = 3
	),
	ticks = Attributes(
	ranges_labels = (automatic, automatic),
	formatter = Formatters.plain,
	textcolor = (tick_color, tick_color, tick_color),
	rotation = tickrotations3d,
	fontsize = (tsize, tsize, tsize),
	align = tickalign3d,
	gap = 3,
	font = lift(to_3tuple, theme(scene, :font)),
	),
	frame = Attributes(
	linecolor = (grid_color, grid_color, grid_color),
	linewidth = (grid_thickness, grid_thickness, grid_thickness),
	axislinewidth = (axis_linewidth, axis_linewidth, axis_linewidth),
	axiscolor = (:black, :black, :black),
	)
	)

or here (I'm not sure if it works from inside @recipe)

Makie.jl/Makie/src/makielayout/blocks/scene.jl

Line 32 in 996f586

Makie.axis3d!(ls.scene, limits)

to prevent axis from being scaled by scene transformations. To get scene transformations to trigger limit resets in Axis3D, adding ls.scene.transformations.model to the lift inputs should be enough here

Makie.jl/Makie/src/makielayout/blocks/scene.jl

Line 20 in 996f586

limits = lift(blockscene, ls.scene.theme.limits) do lims

You can fix this locally by replacing the axis with the same changes:

f,a,p = scatter(rand(Point3f, 10))

delete!(a.scene, a.scene.plots[1])
limits = lift(a.blockscene, a.scene.theme.limits, a.scene.transformation.model) do lims, _
    if lims === Makie.automatic
        dl = boundingbox(a.scene, p -> Makie.isaxis(p) || Makie.not_in_data_space(p))
        if any(isinf, widths(dl)) || any(isinf, Makie.origin(dl))
            Rect3d((0.0, 0.0, 0.0), (1.0, 1.0, 1.0))
        else
            dl
        end
    else
        lims
    end
end
Makie.axis3d!(a.scene, limits, transformation = :nothing)
sort!(a.scene.plots, by = !Makie.isaxis)
``