Use antialiasing for the circles in the 3D editor rotation gizmo

[Calinou]

Follow-up to #51250.

This is a crude approach that relies on drawing a second translucent circle. While not as good as proper polygon antialiasing or 2D MSAA, it looks OK in practice.

Preview

100% editor scale

Before	After

200% editor scale

Before	After

[floppyhammer]

Could we make the axis letters still visible even when the axes point away from the camera?

In Blender:

What we have:

Such way we could avoid some weird moment at which none of the axis letters is visible and make the gizmo more recognizable.

[Calinou]

Could we make the axis letters still visible even when the axes point away from the camera?

This should be done in a separate PR. cc @LightningAA

[AaronRecord]

What we have:

@floppyhammer
Did the letters being offset weird happen before #51250? I don't think I changed any of the letter positioning code, and it still looks fine to me (at least on 3.x):

Also apparently they've updated the blender rotation rotation gizmo since 2.91 which was what I had installed, I do like the new one even more.

[AaronRecord]

This is a crude approach that relies on drawing a second translucent circle. While not as good as proper polygon antialiasing or 2D MSAA, it looks OK in practice.

Could you add a before and after screenshot so it's easier to see the difference?

Also, how much work would it take to implement proper antialiasing to draw_circle(...)?

[Calinou]

Could you add a before and after screenshot so it's easier to see the difference?

I added comparison images to the OP.

Also, how much work would it take to implement proper antialiasing to draw_circle(...)?

I don't know, I haven't read about implementing antialiasing for circles specifically (unless they're polygon-based, but I'm not sure if Godot's are).

[AaronRecord]

I'm not sure that before image is completely accurate, the text color change was from #51250 (it doesn't really matter though, it still showcases the antialiasing).

[floppyhammer]

@LightningAA Yes they did. And the offset might be caused by display scaling.

At v4.0.dev.custom_build [a4c8637], this occurs

Display Scale 150%

Display Scale 100%

[AaronRecord]

@floppyhammer I'd open a separate issue for that then to keep this PR on topic.