4 ms·

Perlin noise

113 points by bpierre 10y ago

kleer001 10y ago
Ah, the classic! There's tons of other lovely noises too. Interested in more? Check out some SIGGRAPH stuffs from Mr. Perlin.
drcode 10y ago
Hmm... Perlin noise is a lot more complex to generate than I was expecting.
- mrspeaker 10y ago
  You don't win an Academy Award for Technical Achievement for Math.random()!
- chipsy 10y ago
  Many folks looking for a Perlin-like effect end up using the diamond-square(or "midpoint displacement") algorithm, which has a similar look but a somewhat simpler implementation: For each segment take the midpoint of the linear interpolation and add noise at a smaller magnitude. Recurse in until you are at the desired scale. In 2D, flip the sample points between a "square" pattern and a "diamond" pattern each time to avoid a boxy tiled look. The biggest downside of this method is that it's much less flexible about scaling: to get more resolution you have to double each dimension.
amelius 10y ago
Can't this be done more easily by solving a differential equation and setting some random boundary conditions?
- banachtarski 10y ago
  No not at all. Think for a bit about what the closed form solution of the final generated function is for any of the examples given. Then think of the differential equation that it satisfies (with N boundary conditions for every segment of the partition). There's no way solving that is easier than what is done in the article. Even before doing that, there are plenty of other methods that still aren't as efficient, which was one of the main goals of the algorithm.
malanj 10y ago
When I was in high school I used Perlin noise to create some 3D terrain. Being young and naive I emailed Ken Perlin and asked him some questions about it. To my surprise he responded and was super nice :-)
- Kronopath 10y ago
  As a student at NYU working with him on one of his research projects, I can confirm that yes, he's a pretty nice guy.
VMG 10y ago
Time to post his website again http://mrl.nyu.edu/~perlin/ http://mrl.nyu.edu/~perlin/ Needs to be ported to webgl some day
- kaoD 10y ago
  > Needs to be ported to webgl some day There are many shader implementations of continuous noise. Most should be WebGL compatible. EDIT: https://github.com/ashima/webgl-noise https://github.com/ashima/webgl-noise there you go :) Includes classic noise (Perlin I guess?) and Simplex.
  - Retr0spectrum 10y ago
    There's another cool WebGL simplex demo here: http://alteredqualia.com/three/examples/webgl_terrain_dynamic.html http://alteredqualia.com/three/examples/webgl_terrain_dynami...
  - VMG 10y ago
    I posted it because he has dozens of demos like the noise generation, all written in Java unfortunately.
david-given 10y ago
See also Simplex Noise, Perlin's 2001 replacement --- it extends to an arbitrary number of dimensions, and it's cheaper: http://webstaff.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf http://webstaff.itn.liu.se/~stegu/simplexnoise/simplexnoise....
colinthompson 10y ago
This is a really nice write up! The graphs really show how a noise signal is built up of its components. Additionally, while un intentional, it also shows how Perlin noise can exhibit "gridding" artifacts from the regular spacing at integer boundaries. This is especially true when used to create tangents based on the signal.
- Sharlin 10y ago
  Yep; as described in the "Improving Noise" article, the gridding is greatly reduced if you use the "smootherstep" function which has a continuous second derivative in addition to first.
Rexxar 10y ago
Fun fact: there is a C reference implementation of Perlin noise directly in the svg specification : https://www.w3.org/TR/SVG/filters.html#feTurbulenceElement https://www.w3.org/TR/SVG/filters.html#feTurbulenceElement
jordigh 10y ago
I found the following libnoise (C++ Perlin noise lib) tutorial very helpful: http://libnoise.sourceforge.net/tutorials/index.html http://libnoise.sourceforge.net/tutorials/index.html
fordred 10y ago
I remember implementing simplex noise in verilog a few years ago. It took me a while to get my head around it, but eventually something just clicked, and the results were very impressive too.

113 points by bpierre 10y ago

Ah, the classic! There's tons of other lovely noises too. Interested in more? Check out some SIGGRAPH stuffs from Mr. Perlin.

drcode 10y ago

Hmm... Perlin noise is a lot more complex to generate than I was expecting.

mrspeaker 10y ago
You don't win an Academy Award for Technical Achievement for Math.random()!
chipsy 10y ago
Many folks looking for a Perlin-like effect end up using the diamond-square(or "midpoint displacement") algorithm, which has a similar look but a somewhat simpler implementation: For each segment take the midpoint of the linear interpolation and add noise at a smaller magnitude. Recurse in until you are at the desired scale. In 2D, flip the sample points between a "square" pattern and a "diamond" pattern each time to avoid a boxy tiled look. The biggest downside of this method is that it's much less flexible about scaling: to get more resolution you have to double each dimension.

amelius 10y ago

Can't this be done more easily by solving a differential equation and setting some random boundary conditions?

banachtarski 10y ago
No not at all. Think for a bit about what the closed form solution of the final generated function is for any of the examples given. Then think of the differential equation that it satisfies (with N boundary conditions for every segment of the partition). There's no way solving that is easier than what is done in the article. Even before doing that, there are plenty of other methods that still aren't as efficient, which was one of the main goals of the algorithm.

malanj 10y ago

When I was in high school I used Perlin noise to create some 3D terrain. Being young and naive I emailed Ken Perlin and asked him some questions about it. To my surprise he responded and was super nice :-)

Kronopath 10y ago
As a student at NYU working with him on one of his research projects, I can confirm that yes, he's a pretty nice guy.

VMG 10y ago

Time to post his website again http://mrl.nyu.edu/~perlin/ http://mrl.nyu.edu/~perlin/ Needs to be ported to webgl some day

kaoD 10y ago
> Needs to be ported to webgl some day There are many shader implementations of continuous noise. Most should be WebGL compatible. EDIT: https://github.com/ashima/webgl-noise https://github.com/ashima/webgl-noise there you go :) Includes classic noise (Perlin I guess?) and Simplex.
- Retr0spectrum 10y ago
  There's another cool WebGL simplex demo here: http://alteredqualia.com/three/examples/webgl_terrain_dynamic.html http://alteredqualia.com/three/examples/webgl_terrain_dynami...
- VMG 10y ago
  I posted it because he has dozens of demos like the noise generation, all written in Java unfortunately.

david-given 10y ago

See also Simplex Noise, Perlin's 2001 replacement --- it extends to an arbitrary number of dimensions, and it's cheaper: http://webstaff.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf http://webstaff.itn.liu.se/~stegu/simplexnoise/simplexnoise....

colinthompson 10y ago

This is a really nice write up! The graphs really show how a noise signal is built up of its components. Additionally, while un intentional, it also shows how Perlin noise can exhibit "gridding" artifacts from the regular spacing at integer boundaries. This is especially true when used to create tangents based on the signal.

Sharlin 10y ago
Yep; as described in the "Improving Noise" article, the gridding is greatly reduced if you use the "smootherstep" function which has a continuous second derivative in addition to first.

Rexxar 10y ago

Fun fact: there is a C reference implementation of Perlin noise directly in the svg specification : https://www.w3.org/TR/SVG/filters.html#feTurbulenceElement https://www.w3.org/TR/SVG/filters.html#feTurbulenceElement

jordigh 10y ago

I found the following libnoise (C++ Perlin noise lib) tutorial very helpful: http://libnoise.sourceforge.net/tutorials/index.html http://libnoise.sourceforge.net/tutorials/index.html

fordred 10y ago

I remember implementing simplex noise in verilog a few years ago. It took me a while to get my head around it, but eventually something just clicked, and the results were very impressive too.