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Comment by siraben | Hacker News Reader

One recent notable achievement by Minecraft@Home was the discovery[0] of the start screen panorama seed which was seen from Beta 1.8 up to 1.12. Reverse engineering Minecraft seeds is an impressive feat given that the search space is so large. The finding of Pewdiepie's survival Minecraft world seed was achieved (without Minecraft@Home) despite him revealing his coordinates via F3 only twice in the entire series[1][2][3].

[0] https://www.reddit.com/r/Minecraft/comments/hthrmk/big_news_...

[1] https://youtube.com/watch?v=LE8ml2hZVZM

[2] https://youtube.com/watch?v=MbAymA6OAa4

[3] https://youtube.com/watch?v=qWnTRNw4mDY

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I should also follow up with a technique that might be of interest to programmers. Some Minecraft blocks have textures that appear rotated in one of four ways. Turns out this rotation is pseudorandom, the rotation number is a result of seeding Java's rand.nextLong() with the (x,y,z) coordinate of that block.[0] This has been used for "malicious" purposes such as finding the location of a base from a single screenshot, which can lead to its destruction on anarchy servers. The author of the linked video used a CUDA search to find the location of a wall of netherrack.

[0] https://youtube.com/watch?v=6__hO4cc1pA

Aside: 2b2t is the most notable of MC anarchy servers. Whenever I read about it, I'm amazed at the machinations of the people that play there. It's kinda like reading Eve Online after action reports of their big battles. I've no inclination to play on 2b2t, but it's great reading all the same.

I have the same feeling about Dwarf Fortress. I absolutely love reading DF stories (see [0]), but the couple times I tried to play I just couldn't get into it.

[0] https://lparchive.org/Dwarf-Fortress-Boatmurdered/

I'm with you. Also hopeful that the DF steam release comes with a slightly easier to use UI.

If you want similarly hilarious stories, try rimworld.

I'm curious about what the implications of some of these projects will be for 2b2t. Given that the seed is known, couldn't people start finding bases from screenshots using some of these clusters of 'rotations of textures 'tricks?

Yes, these techniques have been used to find bases and destroy them. Along with the texture rotation trick, there's also the position of bedrock whose distribution is fixed in every Minecraft world, so if you show exposed bedrock during a base tour you are at risk of leaking coordinates. Natural terrain is also another factor, so share enough images of the area surrounding the base and it can be leaked similarly.

See https://www.youtube.com/watch?v=I7Jz9RMybfM

Shouldn't...

I know that Minecraft lazily generates the world, so the RNG for an arbitrary location has to be deterministic otherwise you get a mess.

Why isn't the RNG for tiles based on the world seed and the location? That's at least a billion times more search space, still deterministic.

>One recent notable achievement by Minecraft@Home was the discovery[0] of the start screen panorama seed which was seen from Beta 1.8 up to 1.12.

Can't this be done by reverse engineering the .jar files? You'd think that the start screen would be procedually generated from a seed (eg. rather than load_world_from_file("start_screen.map"), you'd do generate_world_from_seed("my seed"), because that's way easier than hard coding in the generated world.

The start screen is just an image with some distortion.

I never thought about cracking seeds but apparrently based on location and details of the terrain its not impossible:

https://gitlab.com/taleden/MCeed-A

There is a really interesting ongoing project to find the seed used for the default world and server icons:

Part 1: https://www.youtube.com/watch?v=lbR8ZY1Nsm8

Part 2: https://www.youtube.com/watch?v=eC7f9tMslVE

Part 2 covers most of the efforts to reverse-engineer the seed.

This is quite fascinating, I hope they find it, I'm surprised they havent just emailed Mojang about it.

Part 2 of the videos mentions that Notch replied, saying that he doesn’t remember where the image is from, and that it’s likely coming from a world generated with a random seed.

Dinnerbone has also commented on reddit threads saying they support the project, but they don't think there's anything else mojang can do to help.

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