Add missing max. number of samples (MSAA) check

[bruvzg]

Fixes #9908.
OpenGL ref - glRenderbufferStorageMultisample

[akien-mga]

Maybe display the value of GL_MAX_SAMPLES too for clarity? Otherwise it's trial and error to find out the GPU limitation I guess?

[bruvzg]

Done

[vnen]

Hm, would be interesting to retrieve this value in-game somehow, so if we add a "Graphics Options" menu, it's possible to limit to the player's hardware capability.

[akien-mga]

More globally, we could have something like Engine.get_graphics_capabilities() which would return a dictionary of such driver-dependent values. Might be worth discussing in a new issue though so that we can list what such parameters would be :)

[fabriceci]

Hm, would be interesting to retrieve this value in-game somehow, so if we add a "Graphics Options" menu, it's possible to limit to the player's hardware capability.

Indeed !

If there is a way to retrieve this value, I'm interested.

[Calinou]

@fabriceci Is there a lot of hardware out there that doesn't support MSAA past 8×? (I don't consider 16× MSAA here as it's too expensive to be usable in a modern engine.)

Given Godot's current rendering performance, it might not make sense to expose 8× MSAA to players in the first place anyway. You'll need to give up a lot of visual effects if you want to use 8× MSAA and keep a good framerate.

To be fair, I think we should unexpose 16× MSAA from Godot 4.0 altogether as it's often buggy in graphics drivers and causes weird issues. This is because it's usually implemented as 2× SSAA + 8× MSAA in the graphics driver - we have no control over this. The difference between 8× MSAA and 16× MSAA is very small anyway, even in screenshots.

[fabriceci]

@Calinou I had the warning on mac when I try to set 16x MSAA, that what leads me to this issue, I will limit MSAA to 8X to get rid of that like you suggest and explained.

To be honest, I thought 16x was too much, but by tests, I noticed that it's the only one that be able to remove pixelation effect on cube's edges (a bit less notable here due to compression):

(8x)