The bug
Redstone wire in some situations uses different logic for connecting visually (in which direction the dust texture goes) and logically (what gets powered).
Affected situations
List might be incomplete
Last updated for 18w05a
Situation | Looks like | Is actually | Screenshot |
---|---|---|---|
Redstone wire connecting upwards to slab / stairs / glowstone | line | dot | [media] |
â Glowstone should possibly not show redstone wire on its side since all other blocks which only transfer a redstone signal upwards have no wire on their side.
Code analysis and suggested fix
See comment
Related issues
is duplicated by
relates to
Attachments
Comments

But with Glowstone and Leaves there's no Redstone on the side of the upper block. If you put there glass instead of the Leaves it's connected on the side, so I don't think it's a feature... AND: It's shown as a redstone-point, but it still works as a redstone-line.
It's the same with glowstone and slabs i think.
both redstone pieces would be points, because they are disconnected by the leaves. But because redstone automatically attaches to the torch it will turn into a line. Even without leaves and further redstone the redstone next to the lamp would turn into a line.
We will see what will happen with redstone when jeb rewrites the whole thing. DOn't expect this to be fixed before 1.5
I doubt this is intended because it's inconsistent as True Kuehli pointed out. Confirmed in 15w40b.
Reopening and cleaning up/clarifying ticket.
Not fixed in 15w46a, reopening.
Why was this reopened? I fixed the old report and this is a new problem that should be "won't fix", but I don't want to change this report to "won't fix" because it was fixed!
Redstone dust should not float in the air, but dust on the ground should point to connections.
@Jeb, sorry for the long post again, but I'd really like you to read this. I wrote a clarification of how it works, how it used to work and how it should work, as I did on the bug report of the redstone blocks (MC-5951).
When redstone dust goes up on a slab, as you know, it acts as a diode. Redstone power does go UP, but it does not travel back DOWN. Redstone always points towards power SOURCES or where its powered FROM. Thus, the redstone on top of the slab is redirected towards the source next to the slab, but the redstone next to the slab is NOT receiving power from the redstone on top of the slab and doesn't redirect. (Or stair, glowstone, lamp, anything).
Thus, the redstone next to the slab should NOT direct towards the slab. This works perfecly in 1.8 and before, as shown in the screenshot "Redstone redirection - 1.8 behaviour" which I attached. The opposite is what's shown in "Redstone redirection - 14w46a behaviour", and this is a new bug. If you want me to make a separate report, tell me, but I thought this overview might be helpful.
Besides - you don't seem to be aware of this - the redstone next to the slab still powers in all directions (if its not redirected from elsewhere). This is still the case in 14w46a (See screenshot "Redstone redirection - 14w46a behaviour") and, once again, has been the case since you could place redstone on glowstone and other non-solid blocks. This is such a fundamental component of redstone that I consider it something that should stay untouched, as the fact it works this way has been used in designing many, many, many redstone things. I wasn't aware in the last post that redstone still powers in all directions even when it has a slab with redstone on top of it next to it (and its redirected now), which I am very relieved about. But that's what makes this change so weird.
On another note, this bug was mainly meant for something else to be fixed - the behaviour in "screenshot 2". Diamond blocks are solid blocks and the redstone goes up and down. The blocks at diagonal that seem to block the redstone's path are not solid blocks, and thus they do not block the redstone's path. The glitch here is that the redstone does appear to be cut, but 'logically' as the reporter names it, it's not, and the redstone doesn't power to the side of it (As shown in "Redstone redirection - blocking with leaves"). This is definitely a bug.
I think the reporter also meant for redstone to show a vertical path when travelling up onto slabs, stairs, etcetera. As the game works now, it will show this vertical line if the redstone power travels down the block. That's not the case with the slabs and I do agree with not having redstone in mid-air. Besides, it would be kinda weird to have a dot on the ground and then a vertical line going down, wouldn't it?
I'll mention this again, redstone always points towards where it's powered FROM (unless powered from directly above/below, or through a block). If it's a dot, it powers in all directions, and if it's not, it powers on the side adjacent to where its powered from. When it's powered from 2 sides, it doesn't point 'into' or power any side.
In "screenshot 1", it shows 4 situations of diodes, where there's a dot on the ground and then redstone on top of the non-solid block next to it. On the left however, it's not a dot, because the redstone block is a source of power. Just thought I'd clear this up.
So, I suggest, once again, that you revert this bug to what it was as well, and fix the situation shown in "screenshot 2".
I think this makes total sense. I hope I'm not annoying you with my rants!
@@unknown:
I reopened this because not the whole issue was fixed. Here's a tl;dr of the issues this ticket is about:
Redstone doesn't render going up the side of non-solid blocks like hoppers, slabs, stairs or redstone blocks
Redstone doesn't point towards the side of non-solid blocks like hoppers, slabs, stairs or redstone blocks if they have a piece of redstone dust on top (even though they transmit power that direction)
Redstone is visually cut off (both in direction and in going up blocks) by non-solid full blocks like TNT, glowstone, sea lanterns or leaves but functions exactly as if the non-solid full block wasn't there
I won't go into the issues caused by your fix, see @unknown's comment for that. In short, it's even more confusing now.
For the future: If you only fix part of an issue, leave a comment explaining that so tickets aren't reopened even if you consider them done. I will leave this one open so you can decide what to do with it. In my opinion it'd be best if the whole fix was undone and the ticket marked "Won't Fix".
@[Mod] redstonehelper
Thanks for the cleaner overview of what the report is about.
Instead of doing nothing, an issue that could be fixed is the redstone not visually connecting when traveling up through non-solid full blocks, I'm talking about your third point. We could make a new label for that.
Otherwise I completely agree with you. The hopper/slab/glowstone/lamp behaviour is rather confusing, but it makes sense if you know how redstone works. You kinda want to know if the dust powers the block it's next to, and with this 'fix', it will not actually do that properly in all cases.
Redstone does render going up onto glowstone blocks in 1.8 (see screenshot: "Redstone redirection - 1.8, up onto glowstone"), which makes it more confusing indeed because glowstone has the same properties when working with redstone dust (you cant place comparators/repeaters on top of it though). Another bug you could make a separate label for...

i don't think that it can be fixed, because redstone signal on some blocks can travel only up, but can't travel down. How to show this?
@@unknown: I added a bullet point about your screenshot, did I describe it accurately? Do you suggest any changes to the description?
@redstonehelper I actually have no idea what that is and I dont see any comment on the screenshots! :/
@@unknown: I changed the description:
Also see "Redstone redirection - 1.8, up" - the redstone is rendering as going up the side of the full block with redstone on top even though it isn't logically oriented that way
@@unknown a simple line on solid blocks can be misleading, too:
http://s13.postimg.org/enlm87pj9/2015_11_21_04_19_56.png
just a little image showing how redstone connects:
edit: fixed a mistake in the picture
red: from
blue: to
purple: red+blue
But coloring as an indicator doesn't make much sense.(blue and purple REDstone?! And it's harder to see the power level)
@@unknown: See MC-9405 for that.

confirmed 15w49a

affects 15w49b

affects 15w50a

affects 15w51b
Seems to work as expected in 15w51b for the most part. Redstone dust connects through transparent blocks and transparent blocks that can have redstone put on them act like slabs (stairs, hoppers).
Redstonedust still does not run down the side of redstone blocks but redstone blocks are power sources so I don't think it really matters.
Don't know if it affects anything but I am using java 9
The redstone dust next to the slabs in that pic should be a dot, as it powers to the side as well. For the rest though, thats new behaviour, where it connects through unsolid blocks.
Wouldn't it be that the single redstone line leading to the slab powering to the side like a dot be the bug rather then the other way around?
Lines don't power to the side and redstone is suppose to point to connections. The connection in this case being up the slab, or other bock the acts like a slab. Also dots (and lines into blocks) do not transmit power up. So I believe that the line into the slab is correct, and the line powering like a dot a well is the bug.
If you read my earlier comments, you would know why this is. Redstone connects to sources of power, not to power destinations.
The redstone on the slab doesn't power the redstone next to the slab, thus the redstone next to the slab shouldn't connect. As a dot, it powers to all sides, so why would it make sense for it to be a line?
Because when redstone dust powers other redstone dust most people expect them to be connected.
Because redstone dots can power the block next to them but it can not power redstone dust on top of that block. So if it is going to power redstone dust on top of a slab next to it it should be a line, the same as if it was going up a solid bock. (Atleast this is what i expect it to do)

affects 16w02a
Yes Pixie, but as I said, the redstone dust on top of the slab *is not powering the redstone next to the slab*. Redstone dust does not connect to pistons, they are not a power source. They do connect to redstone torches, as they are a power source. An exception to this rule is powering redstone through blocks.
Since redstone dust is a power source for redstone dust around it, redstone dust connects to eachother visually. But since a slab creates a 1-way connection (diode), only the dust on top of the slab redirects.

affects 16w04a

confirmed for 1.9 pre-1

confirmed for 1.9 pre-2
@[Mojang] Jeb (Jens Bergensten):
This is how the redstone is supposed to be when it goes up to a slab or transparent block (only those who can handle redstone of course):
https://bugs.mojang.com/secure/attachment/104663/Redstone%20redirection%20-%201.8%20behaviour.png
This is the current visual glitch:
https://bugs.mojang.com/secure/attachment/104664/Redstone%20redirection%20-%2014w46a%20behaviour.png
NOTICE that the pistons are powered, it is INTENDED, don't change how the mechanic works BUT how it looks.
Thank you!

confirmed for 1.9.2

I can confirm for 1.10.2 what's in
[media], but all other pictures either contain intended behaviour or are not present in 1.10.2. Can anyone confirm something from the other pictures in 1.10.2?
The description should be accurate. Old screenshots may still be attached.

Changed the whole description to match the fact that only two of the screenshots are currently how it's in the game currently. In that process I also shortened it quite a bit, if someone wants to look if there's something missing, there's a "history" tab above the comments.

Affects 16w40a.

The redstone block bug (and observer block as well) might be intended. It looks like they act like slabs in the way that the power can only go up but not down.
Confirmed in version 1.12 the issue of redstone wire visual render not matching connectivity. wire_render_1.12.png
In the older "redstone redirection - 1.8 behaviour.png" picture we can see, that the redstone used to be a dot. And the dot once was a cross.
So like a single dot powering all 4 horizontal adjacent blocks, this behaviour was once consistent with the texture and should therefore be called intended.
So I suggest fixing the issue by remerging it with the dot visualisation, and then getting rid off those inconsistencies together, by displaying connections to all adjacent blocks.
PS.: Consistency helps a lot learning redstone. So I think this bug is not as unimportant as it might seem.

This is not only about the dot, for example look at this picture:
[media]Confirmed. Annoying đ
@unknown, in which version?
@Fabian Röling:
Maybe I didn't manage to say what I was trying to say. So let me take it in chronological order:
Minecraft 1.0 (1.0.0-RC1): The single redstone dust texture changed from a + to a dot. From this on it doesn't look like it is connected to all 4 adjacent blocks anymore but it still powers them.
Minecraft 1.3.1 (12w25a) until Minecraft 1.8: Redstone can now be placed on upside down halfslabs. It is possible to create what we see in the 1.8 picture. While it is irritating, it is still consistent with other behaviour, because we know, that the dot represents a connection to all 4 sides (while not showing them).
Since Minecraft 14w46a: The redstone now connects to the redstone on the slab, but still not to the pistons making it super counterintuitive why it powers them. It really should have stayed a "+" in the first place.
Also notice, how the behaviour never changed. It's just a problem of how to show it.
I hope that clarifies what I tried to say in my last post.
Yours sincerely, Shildifreak
(About the other mentioned issue of the redstone not going up the side of nonsolid blocks: In my opinion thats already how it's supposed to be, because it corresponds to the signal going up the block, but not down. If one would now add the redstone texture on the side of an upside down stair/observer/glowstone/etc. that would make things even more mixed up and irritating.)
Can confirm for 17w43a/b
Can confirm for 17w47b

I tried cleaning up the report since I was not able to reproduce or see some of the described behavior.
Please comment in case a situation is missing. Redstone blocks and hoppers look like a different bug and are reported as MC-124698.
Can confirm for 1.13-pre3
Affects 1.13-pre6
Â
Already included in affected versions đ
Affects 1.13-pre7. Could this also be related to MC-123850 (resolved in 1.13-pre7)?

This seems to be resolved in the latest 1.14 snapshots (tested in 19w14b).

Nope, I still get the same result as in the
[media]screenshot in 19w14b.
add minecraft 1.14.4

Vanilla:
Glowstone should possibly not show redstone wire on its side since all other blocks which only transfer a redstone signal upwards have no wire on their side.
This seems WAI because there is a check specifically just for glowstone
(The check was merged with isFaceSturdy() in 1.13)
Other blocks like observers and pistons now have redstone visually running up the side too
Slabs don't have a solid face on the side so it doesn't show the vertical redstone
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Visual Fix:
Change the direction redstone visually faces matching the logical direction
Code to change is in RedstoneWireBlock.java under getConnectingSide();
Currently, it checks if the block next to the dust is isFaceSturdy() OR HopperÂ
Then checks if the block is isCollisionShapeFullBlock() returns upwards if true else side if false
To change the visual, this should be changed to if isRedstoneConductor() connect Upwards
This is to be more consistent with isPowerSourceAt()
This has a side effect that redstone won't show visually on the side of non-isRedstoneConductor() blocks
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Logical Fix:
Change the direction of dust logically to match vanilla visuals
Code to change is in RedstoneWireBlock.java under isPowerSourceAt();
Currently it checks if the block next to the dust is isRedstoneConductor() and the block above is not isRedstoneConductor() then calls shouldConnectTo()
The check for if the block to the side is isRedstoneConductor() should be changed to isFaceSturdy() OR Hopper
This is to be more consistent with getConnectingSide();

20w12a
[media]Redstone(unpowered) present, all go up
[media]
Redstone not present, only middle goes up
adding the redstone after the fact doesnt make the pistons go up either

@urielsasis After investigation it seems that your bug is MC-9405
Related, but resolved as won't fix.

The "â Â Glowstone should possibly not show redstone wire on its side since all other blocks which only transfer a redstone signal upwards have no wire on their side." is no longer true, redstone blocks and glass both show the redstone going up the sides
This has been fixed in 20w18a.
https://www.minecraft.net/en-us/article/minecraft-snapshot-20w18a