RNG manipulation and you - RNG theory part 1/3

Part one of the RNG manipulation explanation.
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[@PanNic97]

What a random video

[@Haha007]

PanNic97 just another random pun. XD

[@nidhiprasad9673]

Have you turned into ragou?

[@jackmama109]

Hmm yes very random, the topic of rng manipulation definitely doesn’t become a Topic of drama in the next 2 years hm

[@zorbix3652]

**WHEEZE**

[@hobrin4242]

But totally predictable, of course!

[@Earthcomputer]

Great explanation of mechanics that are so closely related to the code. The details are so complex that you basically have to be a code reader to understand everything, but this should give enough of an overview for most people. I will try to get out some more practical tutorials on my channel whilst you do a great job explaining more of the theory :)

[@packediceisthebestminecraf9007]

A stack of likes.

[@fwiffo]

I hope this is a good lesson for junior programmers. Avoid, as much as humanly possible, any kind of global or shared state. Or any kind of state. Shared state might be the most common cause of difficult-to-diagnose or hard-to-reproduce bugs. The fact that there is one instance of Random() that is shared between deterministic world generation, and random game events (dispensers, particles, mob spawning, weather, enchantments, etc. etc.) is sloppy as hell. There isn't some kind of worldwide RNG shortage! Shared state has caused all kinds of other crazy bugs in Minecraft in the past (remember that stupid bug where fence-posts and chests had globally shared hit-boxes?) I assume these bugs are ancient; pity the poor Mojang developers working on that codebase. God bless Notch, but he'll admit himself he's not a professional programmer.

[@Xcom6000]

Its often the bugs that makes this game more interesting. A clean minecraft would have been far less fun to play.

[@Arm3dWithWings]

Indeed, buggy games-> more "features." Also, pretty sure that "stupid fence hitbox bug" along with any type of pane, iron bars, etc. was used in remote redstone with globally shared hitboxes (not completely sure it was the same hitbox bug, but it was related and fixed in the same version iirc). If everything was exactly as mojang wanted, it would be pretty dull.

[@fwiffo]

Minecraft is pretty much the only piece of software that is made better by bugs, on balance.

[@JoeTaber]

The right way to fix this "bug" is to separate world gen random from other uses of random. I imagine this would be easy enough to implement as a point release fix for 12.2. (But I'm notoriously bad at estimates, so grain of salt etc.) It really seems like a very junior mistake to reuse rand between such different subsystems, and resetting the seed should be a huge red flag.

[@theosib]

This video was majorly interesting to watch!

[@Redz]

Very neat explanation about how everything rng works!

[@Haha007]

Nice video. Finaly someone shows some code of stuff that he explains. Thx for the explanation.

[@liamkeough8775]

gg mojang nice explanation

[@asailijhijr]

Dude, you are so much better at MS Paint than anybody else I've seen do coding explanations in paint.

[@mrfincher]

very nice and interesting video! love to see more!

[@shanefking898]

wow I wish to someday be as comfortable with minecraft mechanics as you are. You have taught so many people so many interesting creations. Thank you, sincerely, for your videos. One of the smartest players probably ever.

[@cezerelecrucio9717]

The idea of up and down ticks is interesting, it's almost like tickspeed is your tempo and updates happen on 8th and 16th notes instead of every quarter note like you'd expect.

[@marcelofaraujo]

Lots of fun! Thanks!

[@Nooticus]

Very informative video indeed!

[@chrisja1998]

Good Explanation xcom

[@andreaaristokrates9516]

An hour long you said? That'd be like 2/3 of one lecture, seems reasonable, but a little short. Would watch.

[@JasonGamingForever]

I am fascinated by this but please demonstrate it like when you say you can get the tree to drop a sapling then I think it would be great to see it happening

[@Xcom6000]

2No2Name made a video on this. In his video he didn't do leaves but it was about ores, same concept.

[@alexvance0]

which of the 7 categories of updates like player updates, weather, mob spawning etc- which one would breaking an ore block like diamond ore fall in, would it be player updates or tile entites? Edit: nvm, rewatched a part i was confused on and answered myself. thanks

[@HorochovPL]

Object names like theProfiler, thePlayerManager... "the" kinda hurts my eyes. Unless it's THE (one and only true) profiler. :D

[@Eta7400]

Nice! Also, just "minor" detail: in tick phases, the "redstone" you're referring to is likely tile ticks. You skipped block events (pistons, beacons, spawners, echest etc) and entities which would be between village logic (door registration/golem spawning/siege?) and tile entities

[@Xcom6000]

There are tons of code that doesn't use the world random so they can be skipped. I left the most stuff out that doesn't serve much of a purpose in RNG and made it far simpler.

[@ners6512]

Not a single dislike... Woah

[@megamlgman7662]

look what you've done

[@anthonywilson620]

So you could use this to make wither skeletons drop their skulls every time? Cool! This video is great for explaining things about code to people who don’t code, although I wouldn’t know, becuase I code with 3 languges. One question I do still have though, is would it work the same (or similar) on the Bedrock Edition of Minecraft? Probably not, right?

[@Xcom6000]

Doesn't work in the nether at all and bedrock, noone knows.

[@anthonywilson620]

Xcom6000 Guess I’ll have to start testing!

[@natetolbert3671]

You should have used this knowledge to write a mod script for Max rng returns when 1.12 was a thing. Would have been easy. Just continuously call nextint() method in a loop (with a ms or 2 delay @each iteration) and feed it the correct number. Is there a getter somewhere (maybe in the Rand class) that returns the rng value upon reset when given a seed and location?

[@natetolbert3671]

Nm it's a bit more complicated. Easier just to override method.

[@anunayy]

"Everyone is aware about what a chunk is".. So why did you explain it? lmao. Amazing video btw.

[@Xcom6000]

I dono : ) Nothings scripted so I repeat random stuff sometimes.

[@packediceisthebestminecraf9007]

Because minecraft bedrock players don't know what a chunk is, there is no F3 + G

[@FireDramine7]

@@packediceisthebestminecraf9007 eh I mean that says nothing. I knew what a chunk was before I knew how to orient a chunk with f3

[@packediceisthebestminecraf9007]

@@FireDramine7 That's probably because you watched a lot of minecraft vids. I didn't know what a chunk was until i started playing the java edition and i found F3 + G

[@HeroixMusic]

What is the reason behind Weather being the second thing the game checks for?

[@strawberrystrawberry7149]

its halfway through and im spacing out i am so lost. it'll definitely take me a few tries to get this information through my head- no fault of anyone but me, though! this is a really interesting topic, glad i found it :>

[@feschber]

Could you please tell me where you got the minecraft code from? I once decompiled it but all variables and functions don't have proper names then and I would have to find them all. Is that actually what you guys did or is there a different way of getting the source? 🤔 I'm very interested in reading the code so thanks in advance ☺

[@feschber]

It's so funny that they just hardcoded a seed 😄

[@feschber]

Has that got something to do with the /locate command maybe?

[@Xcom6000]

Search for MCP on youtube. Its a few steps to it but tons of tutorials on it.

[@feschber]

Xcom6000 Thanks a lot I just found it on the wiki

[@natetolbert3671]

Out of curiosity, how did you acquire the src? Did you use reverse engineer w a decompileror or was it leaked? I remember trying to find it online like 6 or 7 yrs ago.

[@elithecoder]

Minecraft is released in a jar file, which isn't compiled. JAR stands for Java Archive so it actually can be uncompressed to get the source code.

[@whatis4295]

You can use MCP to decompile the code and using some mappings, it can rename files to friendly to understand names. Minecraft is closed source, so the code is not released, especially not in the jar file, but Mojang does provide mappings to help modders.

[@DunnickFayuro]

So in theory, I could manipulate the rng to spawn only creepers in a given space?

[@Xcom6000]

In 1 chunk only, its only possible to manipulate creepers past 1 chunk in 1.8 and lower versions.

[@hobrin4242]

@@Xcom6000 ic on 2b2t we are gonna start fighting with creepers instead of crystals

[@saadamin6951]

I think why seeds are generated using perlin noise and not RNG is that because RNG is a much more intensive process than generating using math

[@fashnek]

?? RNG is math.

[@saadamin6951]

@@fashnek I meant to say "RNG is a much more intensive process for terrain generation than using perlin noise" If you still don't get it, I'm trying to say is the RNG algorithms take up more CPU power than using a perlin noise algorithm. I'm 99% nextInt and Math.random() will just take up a lot more power than int VarName=5*1;

[@hobrin4242]

Wrong! If only trees would generate at the same location every time at the same coordinates. The order of the chunk population is a factor too because I think some trees (tree A) can grow into other spots rendering them unavailable for other trees (tree B), but tree B could also grow first and block tree A. (That is just my logical explanation I thought of without looking at code, but it makes sense.) (This is a huge problem in seed overlay, a hack where you generate part of the world client side and compare it to the real world to see what exactly has changed and trace people's path)

[@anoob8582]

Mojang wants to know your location

[@ralphy1054]

Does rng manipulation work in 1.14.4 or the 1.15 snapshots?

[@nisse7798]

no

[@EchoFolf]

sadly nope

[@mamupelu565]

Where do you download minecraft source code?

[@Usedtobestankrewww]

What were you doing to find this.

[@josechristianduarter]

where did you get minecraft source code?

[@user-ut1hq1wz3q]

Жалко что нет переводов, разобраться бы во всём этом)))

[@flo0778]

I still don't understand why getting a random number for some coordinate should have any impact on the rest of the world. It should be just a deterministic hashing of the coordinates with the world static seed (ex : isMension= new Random(seed + coordinates).nextBoolean()). This code is flawded.

[@konoashi]

Because it set the random algorithm seed using structure coordinates that are themselves based on map seed (not to confuse with algo seed), then every event in the game that are pseudo random use the next(next(next(...next(seed)...))) so the last generated structure which is going to set random algo seed is going to determine the pseudo randomness.

[@flo0778]

​@@konoashi Despite "because", your statement does not address my point

[@konoashi]

@@flo0778 then I did not understand your question if there's even one in a first place

[@sanpai6785]

Doesn't that mean that technically there can be 4 mantions next to each other

[@hobrin4242]

correct, you understood that part

[@JayTailor45]

+Xcom6000 How can I get the code ?

[@dontsubme1891]

I want you to rng manipulate The Matrix

[@gwandnefusicharainerwingl4892]

Uggh Eclipse

[@25NN25]

uggh java*

[@feschber]

Why don't you like eclipse?!

[@gwandnefusicharainerwingl4892]

i just prefer intellij idea

[@brickie9816]

Is it still working on 1.15 or 1.16?

[@harrypotter5460]

No, something changed after 1.12

[@brickie9816]

@@harrypotter5460 ok thanks

[@creationfied]

?

[@venkyman4985]

which version is it?

[@Xcom6000]

1.12

[@sukikurai]

Can i just get a video telling me how to, for example, manipulate how many diamonds I get from an ore, I don’t understand most of this I just want to be able to do it

[@hamix0137]

g

[@royliu2864]

2nd comment

[@nowymail]

Requires lots of work. Doesn't work with the newest version. Meh.

[@maheshwariravichandran6866]

Read my name

[@dontsubme1891]

I want you to rng manipulate The Matrix