MC-124985Terrain population is different from old generation
See attached screenshots. Trees, ores, sand patches, flowers, tall grass, lava and waterfalls, etc are different.
For reference, the screenshot without lavafalls is 18w06a and the other one is 1.12.2.
Linked Issues
Normal
![[Mod] redstonehelper](../../../data/avatars/users/10122.svg){kind=small}
Created Issue:
Terrain population is different from old generation
See attached screenshots. Trees, ores, sand patches, flowers, tall grass, lava and waterfalls, etc are different.
Attachments2
See attached screenshots. Trees, ores, sand patches, flowers, tall grass, lava and waterfalls, etc are different.
For reference, the screenshot without lavafalls is 18w06a and the other one is 1.12.2.
![[Mod] Neko](../../../data/avatars/users/92901.png){kind=small}
relates to
relates to
![[Mod] Michael Wobst](../../../data/avatars/users/37868.png){kind=small}
ProfMobius (Thomas Guimbretiere)is duplicated by
![[Mod] NeunEinser](../../../data/avatars/users/39263.png){kind=small}
relates to
The Bug
It seems like, this bug was missed when world generation changed back in 1.13.
Compared to 1.12.2, mushrooms generate much less commonly in 1.13 and any version after that.
Note that there are differences in population in general (see MC-124985), which is why for example trees and lily pads won't match up
How to reproduce
- Generate a new world with seed 91 in 1.12.2 and run /tp @s -330.81 65.75 164.31 124.50 27.15
- Generate a world with the same seed in the current version and run /execute in minecraft:overworld run tp @s -330.81 65.75 164.31 124.50 27.15
Look around in both swamps and notice how mushrooms are way more sparse in the current version, compared to 1.12
Code analysis by Bartosz Skrzypczak in MC-229557:
The issue has been verified in mod dev environment by adding a conditional breakpoint on block place in RandomPatchFeature#place with condition "new ChunkPos(context.origin()).equals(new ChunkPos(mutableBlockPos)) && blockState.getBlock() == Blocks.BROWN_MUSHROOM" - the breakpoint never hits, so no mushroom blocks are ever placed in the chunk where features are actually generated.
The worldgen refactor changed the way decorations are seeded, so changes are expected. Heightmap should be unaffected though.