Add disable_descend group to disable active descend in climbable or liquid node

[Wuzzy2]

Fixes #11452

This PR adds the group disable_descend to disable players from actively climbing down / moving down in climbable or liquid nodes when you hit the Sneak/Aux1 key.

This is the logical counterpart to disable_jump, which disables climbing/moving upwards instead. I thought it was strange you could disable climbing upwards, but the other way.

How to test

Check out the new climbable nodes in DevTest.

[rubenwardy]

Unfortunately, this feature is not on the roadmap and hasn't received a concept approval. Under the new rules, non-roadmap non-bugfix PRs have 7 days to be concept approved, otherwise they should be closed. These PRs can also have preapproval if they fix an issue that is concept approved

If a core dev wants to support this PR, they may reopen it and apply the "Supported by core dev" label

[Wuzzy2]

What a great way to discourage community members from contributing ever to Minetest again! Nobody even looked at this PR and it is already dead. Contributing to Minetest is so frustrating.

To be honest, this is a really shitty policy. Unless your goal is to get the number of contributors down to 0 as fast as possible.

[SmallJoker]

Well actually this is a very simple implementation and might open up some new possibilities for ITB-style puzzles.

[Wuzzy2]

Thank you, SmallJoker. Does this count as a concept approval? If yes, then please add the "supported by core dev label".

[Wuzzy2]

Bump.

[SmallJoker]

Needs rebase.

[Wuzzy2]

Rebased.

These are the DevTest nodes to test:

• testnodes:liquid_nodescend (new)
• testnodes:climbable_nodescend (new)
• testnodes:liquid_nojump
• testnodes:climbable
• testnodes:climbable_nojump
• testnodes:climbable_move_resistance_4

[Zughy]

Uhm.. I personally don't understand what's the use of a non descendible liquid. Like.. it's a liquid. I think the real problem is disable_jump impeding people to climb and swim upwards: a good game designer wouldn't put ladders when they don't want you to climb. Imho this only makes things messier, hence 👎

[Wuzzy2]

"makes things messier" is a terrible argument if not clarified. That is highly subjective, plus, did you look at the code? It's just a very few lines of code, most of the code added for this PR is just DevTest stuff, not the actual implementation. If even this small change already is too messy, then you can use this argument as justification to reject everything.

Mainly, this change is for consistency. If there is a way to block the upwards movement, it only makes sense to also block the downwards movement. Unsurprisingly, the code for this is very simple.

I think the real problem is disable_jump impeding people to climb and swim upwards

That's not a problem at all. It works exactly as intended and never caused any trouble. Nor do I think my PR does any harm at all.

Some use cases:

• Mystery goo: You can walk on it and don't sink in, but if you walk in from the side, you can rise
• Force field: Blocks that only allow you to move through in one direction (possibly for some puzzle game)

And if you think that's too esoteric, I don't care. :P Minetest is more than just Minetest Game.

[MisterE123]

while I agree with Zughy that the 'disable jump' feature of liquids is a bad design, we are now stuck with that design. this PR is a logical next step in that design, and so, unless we are going to get rid of the disable jump liquid feature and implement disabling jump in another way, we should go ahead with this.

if you can disable jump in a node, you should also be able to disable decending.

Note that no one will actually be using this feature for literal liquids. But as we know, liquid node features are used for much more than liquids. Lets either redesign the whole thing, or do this. Doing this is much easier.

An immediate usecase of this feature is a node that lets you move thru it, but not move up or down in it. (suspension field?) that would be great for puzzle maps. you could extend this to add player velocity upwards to make an antigravity beam.

there are valid usecases for this. lets not do the:

"use-case does not make sense to me so it must be useless"
classic devs``` - quote from greenxenith on discord recently

[Wuzzy2]

Fixes #11452.

(posted to force a link to appear at that issue)

[Zughy]

@Wuzzy2 rebase needed

[Wuzzy2]

Rebase completed. I have no right to remove the label.

[SmallJoker]

Checked my pending reviews and I seem to totally have forgotten about this one.
Sorry - apparently the PR needs a rebase again.

[Wuzzy2]

Rebase completed.

[SmallJoker]

Works

[Desour]

Tested, works. LGTM. 👍