MC-131327Opaque blocks at the top of subchunks (chunk sections) do not increase the world height to the next subchunk
How to reproduce
- Create a new superflat world with void preset
- Make it night time by running this: /time set midnight
- Fill a layer of stone at layer 63: /fill ~ 63 ~ ~20 63 ~20 stone
→
No hostile mobs are spawning - Fill a layer of stone at any other layer: /fill ~ 30 ~ ~20 30 ~20 stone
→
Mobs are spawning correctly on this layer
Note: This bug was introduced in 18w19a
Linked Issues
![[Helper] Misode](../../../data/avatars/users/93314.png){kind=small}
Created Issue:
Mobs don't spawn on blocks at layer 63
How to reproduce
- Create a new superflat world with minecraft:glass as preset
- Make it night time by running this: /time set midnight
- Fill a layer of stone at layer 63: /fill ~ 63 ~ ~20 63 ~20 stone
→ No hostile mobs are spawning- Fill a layer of stone at any other layer: /fill ~ 30 ~ ~20 30 ~20 stone
→ Mobs are spawning correctly on this layerNote: This bug was introduced in **18w19a
Attachments1
Changed Description:
How to reproduce
- Create a new superflat world with minecraft:glass as preset
- Make it night time by running this: /time set midnight
- Fill a layer of stone at layer 63: /fill ~ 63 ~ ~20 63 ~20 stone
→ No hostile mobs are spawning- Fill a layer of stone at any other layer: /fill ~ 30 ~ ~20 30 ~20 stone
→ Mobs are spawning correctly on this layerNote: This bug was introduced in
**18w19a
![[Mod] Michael Wobst](../../../data/avatars/users/37868.png){kind=small}
Changed Description:
How to reproduce
- Create a new superflat world with minecraft:glass as preset
- Make it night time by running this: /time set midnight
- Fill a layer of stone at layer 63: /fill ~ 63 ~ ~20 63 ~20 stone
→No hostile mobs are spawning- Fill a layer of stone at any other layer: /fill ~ 30 ~ ~20 30 ~20 stone
→ Mobs are spawning correctly on this layerNote: This bug was introduced in 18w19a
How to reproduce
- Create a new superflat world with minecraft:glass as preset
- Make it night time by running this: /time set midnight
- Fill a layer of stone at layer 63: /fill ~ 63 ~ ~20 63 ~20 stone
→- Fill a layer of stone at any other layer: /fill ~ 30 ~ ~20 30 ~20 stone
→Note: This bug was introduced in 18w19a
Added Linked Issues:
blocks
Added Linked Issues:
relates to
Added Affects Versions: 1.13-pre2
Added Attachments:
Changed Description:
How to reproduce
- Create a new superflat world with minecraft:glass as preset
- Make it night time by running this: /time set midnight
- Fill a layer of stone at layer 63: /fill ~ 63 ~ ~20 63 ~20 stone
→- Fill a layer of stone at any other layer: /fill ~ 30 ~ ~20 30 ~20 stone
→Note: This bug was introduced in 18w19a
How to reproduce
- Create a new superflat world with void preset
- Make it night time by running this: /time set midnight
- Fill a layer of stone at layer 63: /fill ~ 63 ~ ~20 63 ~20 stone
→- Fill a layer of stone at any other layer: /fill ~ 30 ~ ~20 30 ~20 stone
→Note: This bug was introduced in 18w19a
Changed Summary:
Mobs don't spawnonblocks at layer 63Mobs don't spawn in empty subchunks
Changed Summary:
Mobs don't spawn in empty subchunksOpaque blocks at the top of subchunks (chunk sections) do not increase the world height to the next subchunk
Added Affects Versions: 1.13-pre3
Added Affects Versions: 1.13-pre4
Added Affects Versions: 1.13-pre5
![[Mod] NeunEinser](../../../data/avatars/users/39263.png){kind=small}
Added Affects Versions: 1.13-pre6
Added Affects Versions: 1.13-pre7
Added Assignee: 
ProfMobius (Thomas Guimbretiere)
ProfMobius (Thomas Guimbretiere)Added Fixed Versions: 1.13-pre8
Added Attachments:
![[Mod] violine1101](../../../data/avatars/users/92858.png){kind=small}
Added Affects Versions: 1.13-pre8
Only 63? Not 62, not 64, not 127, only 63? Then it might have something to do with sea level (squid spawning etc.), because I don't know anything else that is fixed on level 63.
Yes, blocks at 63 and mobs spawning at 64 is the only layer it happens with.
It definetly seems to have to do with sub chunks and if there are blocks above. If you have a layer of stone at the top of a sub chunk and nothing above, no mob can spawn there.
They do spawn at layer 63, if there is also a layer of stone at 66.
Simply adding one stone block per chunk at layer 64 does not change anything tho, even tho the sub chunk level should now be raised. So maybe it's when the higest block of the highest subchunk as sky light access?
Tested what I described above at layers 15, 31, 47, 63 and 127
Confirmed for MC 1.13-pre1.
Fabian Röling: the affected layer is 63. I tried to reproduce this bug with other layers but nothing.
As you said, it might have something to do with sea level.
Subchunks are calculated individually for x/z since 1.9 or 1.10. Maybe the height map is not being adjusted properly when there's an opaque block at the top of a subchunk (previously, an opaque block at the top of a subchunk would also make the subchunk above it eligible for spawning)
To test this theory, try it at any other place where y = 16n - 1 (so 15, 31, 47, 63 etc) and see if you get the same results.
Eta740 Yeah, I did that. I checked 127 for >63 and all sub chunk borders <= 63
Actually, due to this bug
MC-68565does no longer happen, because mobs cannot spawn there at all now. The actual cause ofMC-68565si probably not fixed, tho.I tested it with a 16*16 Platform of stone in a chunk:
It looks like it is as @Eta740 said it already:
I tested it too. Eta740 is right.
Eta's theory confirmed by one more tester!
Error is present at all sub chunk borders.
Is this correct?
In that case, title should be changed to "Opaque blocks at the top of subchunks (chunk sections) do not increase the world height to the next subchunk" or something similar. Also, summary is misleading, since empty subchunks should not attempt to spawn mobs other than this 1 exception.
Better? I don't really see a problem with the description.
Cannot reproduce in MC 1.13-pre6. Can someone alse try to reproduce it?
Can still reproduce.
I can't, weird... I'll try to reproduce it again.
I did a similar test to Ray in 1.13-pre8 and got the same results. I feel this could also cause erratic spawning at sub-chunks near the surface, creating areas where mobs don't spawn at all.
This bug seems to be fixed for 1.13-pre9. In my testing, mobs spawned on all platforms regardless of whether they were below, at, or above a subchunk.
Is this still an issue in release 1.13?
If someone knew, they would add the version or comment. There are currently 3436 open bugs that do not have the version 1.13 added yet. Please don't comment on all of them.
And please remember that every comment on a report sends as many mails as the number next to "watch this issue", in this report 23 at once.
Can confirm the 'how to reproduce' doesn't work in major version 1.13. To the best of my testing, this has been fixed.
Will wait for comment of [Helper] Misode before resolving as fixed.
Kumasasa Sorry for this late response but I wasn't able to test this until now. I can indeed confirm that this is fixed in the major version 1.13.
No problem, the ticket won't run away :-P