[MC-124950] Cave generation is different from old generation

The bug

If you generate a new world with the same seed in the versions 1.12.2, only the overall terrain seems to be the same. Caves generate entirely different. That affects the nether as well, in fact the nether seems to use the same generator as the overworld now.

This is seed 1 looking up from 0 0 0 in 1.12.2

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This is the same seed in 18w06a:

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Linked issues

is duplicated by 2

MC-125039 Caves changed in new world generator Resolved

MC-125618 New underground world generation differs from 1.12.2 Resolved

relates to 2

MC-125037 Biomes on land and landscape changed in new world generator Resolved

MC-125088 Zombie village instead of normal village and vice versa in new world generation Resolved

Attachments

Comments 2

ProfMobius (Thomas Guimbretiere) 2018-02-12T09:57:43Z

The reseeding of decorations is different but more coherent after the refactor. Heightmaps should be identical, but everything produced post initial heightmap generation might show variations.

NeunEinser 2018-02-12T12:10:38Z

Interesting, thanks for the clarification!
Initial heightmap seems to be the same indeed, some cave entrances or lakes and such might obviously change the height map after the initial terrain was generated, though. 😉