How to make a square point round?

I’m new in VTK.
A square point is constructed in this example (C++ version).

I tried to find how to create a round point but found nothing that could help me. I found this article in Kitware blog how to make a sphere. This works for me, but I’d like to create a round point still. Also I found this issue, but I can’t understand this answer to get a round point.

How to create a round point? I code on Python, but I hope I will be able to understand C++ code.

Best regards,

You can use circle glyphs with vtkGlyph3D or vtkGLyph3DMapper. Probably it is also possible to write a custom shader that renders each vertex as a circle, but for this you need to figure out how shader replacements work in VTK and write the shader code (some useful shader code snippets are here).