[MC-411] Terrain Generation Issues

I created 2 DEFAULT worlds with the seed "LightChase", one in Version 1.3.2 and the other 1.4.2 Pre-release. Both versions give me the same world with a partly generated cave (See Picture 1 and 3), a river that didn't float down (See Picture 2) at where it should be, ork trees and a lake south-eastwards (See Picture 4). I tried to recreate it several times and I was given the same result.

Then, I created a Large BIOMES world with the same seed in 1.4.2 Pre-release. This time, I was given a world with a similar cave yet fully generated (See Picture 6, notice the trees are gone), a Swamp biome which didn't show up in the Default world (See Picture 6, on the right), the same lake at the same position of the Default-world lake (See Picture 5).

I think, and I believe, that it's a generation bug occured because of a code error.

Linked issues

is duplicated by 1

MC-29466 Cave Stop Generating Before Water Sharply Resolved

relates to 1

MC-6820 The generation of terrain surface layer produces local straight glitches (fix included) Resolved

Attachments

Comments 17

Charles-William Crete 2012-10-25T11:17:11Z

Im pretty sure this is not a bug. At lease a very minor bug.

Ezekiel 2012-10-25T11:23:10Z

Sorry, this has always happened to some extent over most updates.

SteelCrow 2012-10-29T03:04:28Z

Looks normal. Not a bug. Caused by a minor change in how the seed is used. As the 1.4.2 generation will consistently produce the same terrain with the same seed, it's definatly not a bug.

Jelly Opera 2012-12-23T10:33:13Z

This generation bug has happened on all of four worlds I've generated in 1.4.6 with random (inputless) seeds. Doesn't seem normal to me at all. I have screenshots of one of the worlds.

kumasasa 2013-01-13T15:30:20Z

Resolved as duplicate of MC-6820 , there are the reasons for this behaviour.

7 more comments

bugi74 2013-01-13T15:40:37Z

The screenshot numbers seem to be mixed up (due to way how JIRA switches order when uploading more or something).

Actually, most screenshots depict a different issue than the MC-6820. I think this issue could be the same or at least related to issue MC-7200 (also reported by me and has a fix).

Would be nice to get seeds and locations if anyone spots similar straight cut surface caves/tunnels. I could easily check the bug then.

Seville Cheng 2013-01-13T15:44:09Z

@Markku Yes it's mixed up. And I agree mine is more related to MC-7200 than MC-6820.

kumasasa 2013-01-13T16:08:02Z

Ok, relinked to MC-7200 but left MC-6820 as a potential relation.

bugi74 2013-01-13T16:40:57Z

I managed to create that same world and gave a bit of surgical knife to the cave generator code...

I first applied the two fixes, but that didn't help, so this issue is NOT related to either MC-7200 or MC-6820.

I then suspected another piece of code and made a specific change to prevent that code working in the relevant coordinates (allowing that tunnel to continue no matter what that suspected code was deciding). And this time the tunnel did continue, like shown in the other screenshot. Thus that suspected piece of code is the reason...

... But the disabled piece of code is an intended feature, though implemented in a bit crude way. Namely, there is specific check in the cave generator code for NOT tunneling into water; it stops the tunnel just before it. It is not perfect, as it makes a sharp cut instead of trying to do some fancy natural shaping (difficult!).

So, this particular case is "intended feature". Changes to it should probably be a feature request along the lines of "more natural caves/tunnels near waters".

bugi74 2013-01-13T16:43:19Z

Added a screenshot for the case when the stop at water -feature is disabled for tunnel generation.

kumasasa 2013-01-13T19:19:50Z

Ok, reopened this ticket.
Leaving the links as "related to"

Ezekiel 2013-07-12T14:01:09Z

Cannot reproduce in the latest version of minecraft

Can you provide a seed?

Seville Cheng 2013-07-12T14:32:19Z

@Ezekiel As I just bought a new computer, you might have to wait for some days so that I could see whether I can reproduce it. Thank you for remembering this issue.

bugi74 2013-07-12T14:49:26Z

Can reproduce in 1.6.2. (Note, the seed, "LightChase", is in the description...)

Note, this issue is more about a somewhat extreme and visually bad effect of an intended coding feature. See my comment earlier and the 'disabled_water_stop_feature' screenshot what happens when the feature is disabled. However, the current operation obviously creates quite disturbing shapes. Mojang needs to decide whether they consider this small enough a problem to leave as "won't fix", or if they want to try to make a better tunnel "shaping" algorithm. Note also that most likely, this same "feature" is the reason why e.g. large ravines can be cut vertically sharply when a river passes through it, etc.

Tails 2013-08-30T17:51:29Z

Resolving this since the upcoming update changes terrain generation quite a bit. If there are any new issues with the new terrain generation, please create a new ticket.

Talven81 2013-11-26T18:48:04Z

No longer valid, complete rework of terrain generation code in 1.7.x

Seville Cheng 2013-11-27T05:08:47Z

@Talven81 The same bug still can be seen in 1.7.x (e.g MC-29466)