Default settings, presets and configuration for dynamic shadows

[x2048]

This PR tunes the way dynamic shadows are configured on the client:

• Fixes State that dynamic shadows, even if activated, need games/mods to opt-in to be displayed #12260
• Tunes the default parameter values
• Tunes the quality presets

The new presets follow these ratios with every quality level:

• Texture resolution is doubled (x2)
• Max shadow distance is multiplied by 1.5

The result is that pixel density and shadow quality near player also increases with every preset.

To do

This PR is a Work in Progress

How to test

1. Start minetest
2. Go to settings, enable shaders
3. Change the presets for dynamic shadows.

[x2048]

Modified look:

[kilbith]

Give me that instead and get rid of the shadow update frames bullshit.

[x2048]

I've made two polls on Discord, here are the results:

I have reduced maximum rendering distance for many presets based on this feedback, to favor more quality over coverage. I also doubled shadow map resolution for High and Ultra High, going for 8192 in Ultra High.

[lhofhansl]

I don't think we even need that max-shadow distance as config option.
We can always make it view_range * 1.5.

[x2048]

@lhofhansl Going to very high view range will kill the shadow quality near the player, and shadow distance is not a priority for high-quality preset. I still think we should have a limit for shadow range.

[lhofhansl]

So with #12364 and can leave shadow_update_frames the way it is, right?

[x2048]

So, this is the current proposal. The presets are as follows:

Preset	Texure resolution	Maximum Range	Filtering	Effects
Very Low	512	62	No filtering	None
Low	1024	93	No filtering	None
Medium	2048	140	3x3 / 9	None
High	4096	210	5x5 / 25	Colored Shadows
Very High	8192	300	5x5 / 25	Colored Shadows

Comments, feedback are welcome.

[lhofhansl]

Hard to say whether these pre-sets are good for everyone. These seem to be good enough.

[lhofhansl]

I still would like if we could derive more things: For example the max shadow distance and shadow map resolution from the view range instead of specific config options... But I happily take this.

[SmallJoker]

Looks good; works.