Remove shadow_sky_body_orbit_tilt setting with the next major release

[Zughy]

Partly fixes #13705 , it needs to disappear from settings as well (@rubenwardy ?)
See #13705 (comment)

To do

This PR is Ready for Review.

How to test

1. Stand on one leg
2. tilt your head by 57° to the right
3. start jumping
4. read

[grorp]

shadow_sky_body_orbit_tilt is a pure client-side setting, so removing it would be no compatibility breakage. You can hardcode a default value of 0.0f for body_orbit_tilt instead of reading the default value from shadow_sky_body_orbit_tilt.

The setting was reintroduced to fix an uninitalized value on the client in some cases. See this comment by x2048:

the problem was in not having a default value in SkyboxParams when deserialization fails of skips the value. I've returned the setting to act as a drop-in value in these cases.

Originally posted by x2048 in #13340 (comment)

It should cause no problems to have a hardcoded default value instead.

[Zughy]

@grorp I hope it's correct

[grorp]

This is what I meant. In theory, this should be backwards compatible, except for singleplayer-only games with a shadow_sky_body_orbit_tilt setting in their game-specific minetest.conf.

Going one step further, we could replace the nil server-side default value with a default value of 0.0 as well, but that could break mods which do something like this:

if not player:get_sky().body_orbit_tilt then
   player:set_sky({ body_orbit_tilt = 60 })
end

---

Anyway, this PR needs a zipgrep. And probably it should get a review by x2048 when you're ready.

[rubenwardy]

Searched in .lua and .conf files:

[Zughy]

@x2048 thoughts?

[SmallJoker]

I don't see how such minor change in settings would need any special treatment. The functionality is not lost. Simply remove all traces of shadow_sky_body_orbit_tilt (looking at doc/breakages.md) and merge this thing. No need to make a big fuss about it.

[grorp]

@rubenwardy Could you do a zipgrep for "body_orbit_tilt" as well? Then we would know whether we can also remove the special nil logic for body_orbit_tilt in set_sky.

(EDIT: With special nil logic, I mean the INVALID_SKYBOX_TILT thing. I didn't see SmallJoker's comment before writing this.)

[rubenwardy]

@rubenwardy Could you do a zipgrep for "body_orbit_tilt" as well?

This is also not present in any .lua or .conf files

[x2048]

@Zughy I guess you'll have to decide it without me: https://irc.minetest.net/minetest-dev/2023-10-01#i_6119219

[rubenwardy]

what action/change does this need?

[grorp]

what action/change does this need?

Removing the INVALID_SKYBOX_TILT thing as well, it only exists because of the setting.

But I'd also be fine with just removing the setting and keeping the INVALID_SKYBOX_TILT thing.

[Zughy]

...and I've fucked up my git history

[Zughy]

Well, let's cut the chase: this PR was initially just a documentation PR. It's clear I have no idea of what I'm doing now and that grorp is babysitting me. Considering also the current git history, I simply invite anyone to take over, as I feel we're all wasting our time at the moment. Closing and labelling for adoption