Hide volumetric fog, SSIL and SDFGI on Mobile/Compatibility renderers

[Calinou]

These features are only supported in the Clustered Forward renderer.

See #55880.

[BastiaanOlij]

I've never liked us doing this in Godot 3 and I'm not sure if we should be doing so in Godot 4.

In Godot 3 I kind of got it with how different the GLES2 and GLES3 renderers became which made it unrealistic to create a game that targeted both renders.

But with Godot 4 this is far more likely where someone creates a game that will use the desktop renderer when deployed to high end computers and the mobile renderer when deployed on lower end or mobile devices.
You don't want to get into a situation where settings are lost just because the developer switches to the mobile renderer to test their game.

[Calinou]

@BastiaanOlij I suppose we could use the read-only property hint which was added in 4.0. This way, settings are still shown and serialized (if previously modified) but you can't modify them.

[BastiaanOlij]

@Calinou maybe, my point merely is that someone might want to support both and removing the settings or even making them read only, just makes that harder to do (for me this btw is a real world scenario, I might be using the desktop renderer for deploying to Windows and the mobile renderer for deploying to Quest, and at times that means running the mobile renderer on desktop to speed up testing).

That said, I guess in such a scenario I need to build something on top of this anyway because I would want to have the settings that are shared between the two renderers be different. Looking for instance at the limitations our R10G10B10A2 buffers on the mobile renderer give will likely mean that I'll want to tweak settings so they look good when the mobile renderer is used.

It almost begs the question if the two renderers need their own set of settings, now there is a hornets nest I'd rather not touch :)

we have discussed a different direction

[Calinou]

Closing per the above comments. This is superseded by #72659, which only changes the documentation but leaves the properties editable regardless of the current rendering method.