Makie.jl: Animating a sequence of meshes

[nitin-ppnp]

If I have a sequence of meshes where the vertices keep on changing while the faces remain the same. How can I create an animated visualization or save in a video/gif? Sorry, but I can't figure it out from the documentation.

[SimonDanisch]

This should work:

scene = mesh(my_mesh)
meshplot = scene[end]
meshplot[1] = new_mesh

[asinghvi17]

You can make the vertices an Observable Array, and update that array.

[nitin-ppnp]

I am doing this:

scene = mesh(vertices,faces)
meshplot = scene[end]
meshplot[1].val = convert_arguments(Mesh,new_vertices,faces)[1]

I don't see any change in the rendered window.

[asinghvi17]

Try update!(scene)?

[nitin-ppnp]

Still unchanged. It did update the scene (the camera view got back to the original), but the mesh remains unchanged.

Btw, I also want to interact using the mouse while the vertices updates. I don't want it to go back to original view.

[SimonDanisch]

Why would you change my example code to:

meshplot[1].val

?!?
Updating the private field val is exactly why it doesn't update the plot...

[asinghvi17]

What happens if you do:

overts = Node(vertices)
scene = mesh(overts, faces)
overts[] = new_vertices
# update!(scene)

(This is the Observables solution, Simon's solution is equally valid).

[nitin-ppnp]

@SimonDanisch It was giving the following error:

ERROR: MethodError: Cannotconvertan object of type GLNormalMesh to an object of type Array{Float64,2}

then I checked typeof(meshplot[1]) and it was Observables.Observable{GLNormalMesh}

meshplot[1].val was of type GLNormalMesh so I tried assigning to it.

[SimonDanisch]

Ok, well the mistake must have been, that you were trying to update it with something that isn't a Mesh, but setting the val directly doesn't help with that (it just circumvents propagating the update to the plot) ;)
I thought you already have a mesh - but if you don't @asinghvi17 solution might be the way to go!

[nitin-ppnp]

@asinghvi17 Thanks! it is working as I want.

@SimonDanisch I used convert_arguments(Mesh,new_vertices,faces)[1] to get a GLNormalMesh. Do I need a different type of mesh?

[asinghvi17]

It's not the type but the way it was assigned. Try meshplot[1][] = newmesh?

[nitin-ppnp]

Got it! Working perfectly :)
I am new to Julia. Is this kind of assignment specific to Makie or something we can find in Julia too? And if it is not a lot of work for you, I would like to know why this work and the previous one doesn't.

[SimonDanisch]

Sorry, you actually run into some pretty confusing behavior of Makie - I didn't realize immediately, because you didn't post the code you actually tried ;) So you should always post what your current code looks like!
The confusing behaviour is that plot[1] returns the signal from convert_arguments(args....)
while plot[1] = new_args... actually corresponds to the input arguments.
So if you do:

meshplot = mesh(arg1, arg2, arg3)[end]
# you will need to do:
meshplot[1] = new_arg1;
meshplot[2] = new_arg2;
meshplot[3] = new_arg3;

This was a work around that I introduced at some point - will try to reevaluate if this is still needed, since it's indeed super confusing!

[nitin-ppnp]

If I am recording this sequence using record function. The camera view is reset when the record loop executes. Here is what I am doing.

msh = mesh(vertices[1,:,:],faces)

After this, I adjust the camera view using the mouse. Next I do

record(msh,"out.gif",1:size(vertices,1)) do i
       msh[end][1][] = convert_arguments(Mesh,vertices[i,:,:],faces)[1]
       end

During the recording, the camera view is reset. How can I render and save with my desired camera view?

[SimonDanisch]

put scene.center = false in front of record

[nitin-ppnp]

Awesome! center is not a member of scene so scene.center doesn't exist but scene[:center]=false works perfectly.

[SimonDanisch]

Did you try it?

julia> using Makie

julia> scene = scatter(rand(4))

julia> scene.center = false
false

Works!

[nitin-ppnp]

Sorry, my bad. It works. In REPL I was using tabs to scene. and it didn't show center so I tried scene[:center] and it worked.

[SimonDanisch]

I see ;) Yeah it's enabled via getproperty which doesn't work with autocomplete :(

[asinghvi17]

You can add it to propertynames for it to work I think?

[SimonDanisch]

Oh, good point! I was meaning to research how I can make autocomplete work :)