1.19: Block Friction Not Working For Thin Blocks

[Syric]

I'm attempting to create a thin, carpetlike block with very little friction, but modifying its friction value has no effect. Is the game checking friction for the block underneath it instead? How can I override this?

[Draco18s]

It's a logged bug that's existed since...basically forever.

I'd get you a link, but the bug tracker is undergoing maintenance.

[Syric]

I can confirm that when I place two of the custom block on top of each other the slipperiness works fine. Are there any methods that let you interfere with the friction-calculation process? I could check for entities stepping on or inside the block and manually set their friction to the desired value then.

[Draco18s]

https://bugs.mojang.com/browse/MC-1127

Resolved as "working as intended"

3 minutes ago, Syric said:

when I place two of the custom block on top of each other

Clarification required.

[warjort]

NOTE: I never looked at this before, this is my quick assessment.

The answer to your question is kind of complicated and inconsistent.

Some places use entity.getY() -1.0D while the main LivingEntity.getBlockPosBelowThatAffectsMyMovement() uses getBoundingBox().minY-0.500001D

So if you are not a full block, it will probably look at the block below, but not always if you are bigger than half a block.

How the boat handles friction is a different story. 🙂

 

Overriding is probably difficult since the checks are calculated using the entities location to find the relevant block.

This is only indirectly related to your block given that the entity will be standing on top of your bounding box.

This means there is no place where it looks at your block during the calculation.

[Syric]

10 minutes ago, Draco18s said:

Clarification required.

My block is as thin as a snow layer. When I put two on top of each other (so with most of a block of empty space between them, like stacking carpets) the friction when walking on top of the top one is correct, suggesting that it's calculating based off the friction of the block below: i.e. the layer underneath it.

This matches warjort's info, which says that the game calculates friction based on the block 0.5 blocks below the bottom of the entity.

Hm. Perhaps it would work if I turned the block below into a 'slicked block' containing its previous state as data somehow and possessing the correct friction. That seems a bit overkill though, so I might just use SpeedFactor instead.

[Draco18s]

40 minutes ago, Syric said:

This matches warjort's info, which says that the game calculates friction based on the block 0.5 blocks below the bottom of the entity.

My info*
I looked at the code for it back in 2013, which was in the linked bug report. Warjort just rephrased it.

40 minutes ago, Syric said:

My block is as thin as a snow layer. When I put two on top of each other (so with most of a block of empty space between them, like stacking carpets)

That's what I thought, but I wasn't sure if you meant like carpets or like snow layers where you can make the block thicker, but still take up less than a full block.

Edited June 28, 2022 by Draco18s