3D handles get smaller when MSAA 16x is enabled (3.x only)

[djrm]

Operating system or device, Godot version, GPU Model and driver (if graphics related):
master bca97e3, Linux 64, Nvidia prorietary divers 387.34

Issue description:

Enabling MSAA 16x makes the editor 3D handles very tiny, it only happens when the level is 16

MSAA 16x

not MSAA 16x

Steps to reproduce:

Link to minimal example project:

[bojidar-bg]

Maybe this is related to the maximum point size on the GPU?

[akien-mga]

We have now entered release freeze for Godot 3.0 and want to focus only on release critical issues for that milestone. Therefore, we're moving this issue to the 3.1 milestone, though a fix may be made available for a 3.0.x maintenance release after it has been tested in the master branch during 3.1 development. If you consider that this issue is critical enough to warrant blocking the 3.0 release until fixed, please comment so that we can assess it more in-depth.

[reduz]

This sounds like a driver bug to me, is it really expected to work like this?

[Calinou]

I can confirm this on commit 39e8aca, on NVIDIA 396.45 on Linux.

16× MSAA:

8× MSAA:

[Calinou]

After fiddling around in nvidia-settings, I can see one possible reason for this. It seems the NVIDIA driver doesn't actually do 16× MSAA, but will rather combine SSAA and MSAA behind the scenes. This would effectively result in billboarded elements getting smaller due to the higher viewport resolution.
The joys of high-level antialiasing APIs, I guess 😉

In nvidia-settings, you can force either:

• 2× MSAA
• 4× MSAA
• 4× SSAA + 2× MSAA (= 8× AA)
• 8× MSAA
• 4× SSAA + 4× MSAA (= 16× AA)

But there's no 16× MSAA option.

Note that the available MSAA overrides will depend on your GPU (I'm using a GeForce GTX 1080).

I haven't tested 16× MSAA in the Vulkan renderer as it causes Godot to freeze and not render anything (#37917).