Perlin noise implementation in p5.js


I noticed the outcomes of noise() function in Processing and p5.js is different (setting the same seeds). Do they use different implementations? Why?

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Let’s take a look at the source!

You’ll have to ctrl-f “noise” to get to the definition:

As far as I can tell (on mobile :grimacing:) they use the same implementation, but use their own native Random-objects. In the end, a result of their environments.

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But I am getting different results (for the same seed). Try this simple code:

float x = 0.0;

void setup() {
  for(int i = 1; i <=10; i++) { 
   x = x + 0.01;
var x = 0.0;

function setup() {
  for(var i = 1; i <=10; i++) { 
   x = x + 0.01;

I get different values from the two sketches (I am using Processing IDE):


The two vectors do not differ for a constant and their ratio is not constant. Nevertheless, they are positively correlated (Perason 0.9999822).

@HEX0x6C We need to look into formatting the code properly in this forum. Do you know how to do that?


No. I do not. Thanks for telling.

Please format your code :blush:

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On the surface it may look identical, but we have to ask ourselves “what is being seeded?”

Java is calling this:
perlin[i] = Math.random();

while JavaScript is calling this:
perlinRandom = new Random();

I assume that Java and JS implement random seeding differently.

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All right, I did it. Thanks for your patience.

I think (I am not an expert on JavaScript random) that the issue here isn’t a Java vs JavaScript implementation of a PRNG (pseudo-random number generator)…

…it is Java vs Chrome vs Firefox vs Safari vs Opera vs etc.

So now the question is: what PRNG does JavaScript use?
The answer: none.
It’s up to the browser

From: How does JavaScript’s Math.random() generate random numbers?

If you want to be able to have specific random seeds produce the exact same effect across Java and JavaScript, and if high-quality randomness is not important to you, then one approach might be to implement your own very simple PRNG in-code in both the Java and JavaScript sketches, and completely ignore the respective language built-in random() / Math.random().

For examples and discussion of simple LCG algorithms for PRNGs, see:


So, thinking about this a little further, your essential issue is that noiseSeed() and noise() in Java are both built on java.util.Random() – and you can’t route around those internal initialization calls, even by providing your own series seeds generated by your own a non-Java source.

So, in addition to needing a cross-platform RPNG for seeds, I believe (?) (on quick inspection) that you cannot then to manually iterate a seed and pass each to noise. Instead, as the library currently stands you would also would also have to write your own Perlin functions.

If you want to start with a cross-language PNRG, I would recommend starting with an extremely simple LCG that is already implemented in Python / Java / JavaScript and gives the same results in each. See this answer re XorShift:

Note however that the given solution for Java is actually returning a long, not an int (!) There is no such thing as a primitive 32-bit unsigned int in Java.

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Okay, I have posted a preliminary cross-language implementation for random / randomSeed, here:

There is no noise / noiseSeed included yet, but that might be built on top of it.


Wow, this is awesome! Thanks for your endeavor!

Glad you like it – thanks for sharing an interesting problem. I would also be curious to hear more about what your application is for cross-language noise.

Good luck, and if you can build on it, please share!

My app is here. Originally I developed it in Processing. Then, I noticed that the sketches in P5.js and Processing generate different coils for the same hash string, hence I posted the question.

Thank you.