Can someone explain noise() aka perlinNoise() function?

Processing Beginners
5

You’re using the function correctly but at the “wrong scale”.

Scale down the noise inputs (so that the noise difference between successive pixels is lesser; i.e. the frequency is reduced) and you’ll get a more expected result:

final float scale = 0.01;

void draw() {
  for(int i = 0; i < width; i++) {
    for(int j = 0; j < height; j++) {
      stroke(noise(i*scale,j*scale)*255);
      point(i,j);
    }
  }
  noLoop();
}

Note that noiseDetail() doesn’t affect the “zoom” or the pattern at a coarse level, but affects the finer detail of the noise pattern – higher values for noiseDetail are more important the more “zoomed in” the noise is.

scaled inputs, with noiseDetail = 4 (default):

image
image602×638 36 KB

scaled inputs, with noiseDetail = 8:

image
image602×638 43 KB

However, back to your original image, the zoomed out view shows us that Processing’s noise function is terrible at large scales – we can clearly see it’s not randomly noisy (in the manner we would like) at all! (Why is perlin noise looping? - #4 by jeremydouglass)