[MC-160939] Biome borders change when upgrading a world to 1.15

The bug

When opening a world from 1.14.4 (or earlier) in 1.15 (since 19w36a), the biome orders change. This is probably a side effect of the Minecraft save files now supporting three-dimensional biomes, and as such probably intentional.

This is problematic since it breaks farms that are based on only allowing spawning places in a certain biome.

To reproduce

Create a new world with the seed 5611121500148513396 in 1.14.4
Run /tp @s -1261.5 131 132.5
Turn "Biome Blend" off
Look at the biome borders
Close the world and open it again in 1.15
→ ❌ The biome borders change

Linked issues

relates to 1

MC-244340 Biome borders change after updating to 1.18 Resolved

Attachments

Comments 9

chenyuxuan 2019-09-17T12:18:35Z

so,from now on,every element of the Array represents biome of a 4*4*4 cube?

[Mod] violine1101 2019-09-17T12:19:33Z

Seems like it, yes.

chenyuxuan 2019-09-17T12:36:57Z

but ,It seems that only first 16 elements counts......

by the way,could you please confirm a bug reported by me?It have been open for more than a week.
MC-160603

[Mod] violine1101 2019-09-17T13:01:36Z

Yes, the only thing that was changed in the snapshots was that the save file now supports three-dimensional biomes. They aren't completely implemented yet.

And yes, we'll get to every ticket eventually, testing bugs just takes a lot of time.

chenyuxuan 2019-09-17T13:21:20Z

In my opinion,It is better to not update old chunks.

only new chunks use the new format and apply the tortuous transform(noise).

otherwise,some machine built in the old version may be broken.

and it is waste to copy old chunk`s biome 64 time , as their biome is not relative to Y.

(It is easy to know that if the format of a chunk is the new one or the old one. as their length is different)

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mojira is not accessible in China.

[Mod] violine1101 2019-09-17T13:24:25Z

As the old and the new chunk biome formats are incompatible, that's not possible. The only way to 'fix' this bug is to completely redo the current biome format, which will not be done.

Please keep in mind that this is a bug tracker, and not a discussion forum. For lengthy discussions, please go to /r/Mojira.

user-f2760 2019-09-18T08:09:16Z

Why exactly is this intended though?

Couldn't the Biomes array (instead of just increasing the int count) be moved to chunk sections, rather than per collumn? This'd make much more sense as well, and not run into future problems, as well as keeping the ability to assign biomes on a 1x1 area...

Additionally, I remember the 1.14 biome rewrite to have as a goal "to not change biome generation results", this is in direct contradiction with a whole rewrite of the generation itself, less than an update ago...

Also, re violine: "The only way to 'fix' this bug is to completely redo the current biome format, which will not be done." they just did that in 36a to allow y dependent biomes already, so that's not really an argument.

(Not intending to start a discussion, just want to hear a reason from mojang)
EDIT: and the last line got completely ignored, well done. And I also wasn't questioning the devs, just wanting to know their reasoning........

[Mod] violine1101 2019-09-18T08:41:53Z

"which will not be done", since they've resolved this ticket as WAI.

This change does not change the way biomes actually generate. It only changes where the exact biome boundaries are.

And again, please keep in mind that this is a bug tracker, and not a discussion forum. For lengthy discussions, please go to /r/Mojira. This is not really the place to discuss Mojang's design decisions.

bdm68 2019-12-03T03:27:45Z

For discussion on how biomes are stored in save files, see the discussion here: A discussion for the changes to how biomes are stored in save files (Java edition)