2D Perlin Noise (gradient noise) range = ?

Matthew Doucette · 2005-01-10T09:24:21

What is the range of 2D Perlin Noise? To be explicitly clear, I am asking about only one layer of 'gradient noise'. Gradient noise is an interpolation of gradients, which is what Perlin Noise actually is. I am *not* asking about 'value noise' which is an interpolation of values. More specifically, I am asking directly about Ken Perlin's actual 1985 implementation of Perlin Noise: http://mrl.nyu.edu/~perlin/doc/oscar.html#noise (Sorry for all that, but there is much confusion out there about what Perlin Noise actually is.) My (on paper) calculated range is -sqrt(0.5)..sqrt(0.5), not -1..1 as everyone assumes. sqrt(0.5) = 0.707106781... Upon testing, my implementation's range is also -sqrt(0.5)..sqrt(0.5). The actual range determined by polling the entire (0.0..256.0,0.0..256.0) x,y range at 0.01 intervals was: min..max=-0.694254..0.695643 (very close to -0.707..0.707) LilBudyWizer also came up with the same range in this thread: (If you choose to read the thread, please note that most responses in this thread completely misunderstood where LilBudyWizer was coming from and what he was asking.) http://www.gamedev.net/community/forums/topic.asp?topic_id=255173 ... If we are correct, to make Perlin Noise output a range of exactly -1..1, the result must be scaled by sqrt(2). Can you please test your own Perlin Noise implementations and see if you have the same results? Thanks. [Edited by - Doucette on November 29, 2004 2:28:09 PM]

Graphics and GPU Programming Programming

Started by Matthew Doucette November 29, 2004 09:11 AM

42 comments, last by Matthew Doucette 19 years, 3 months ago

Anonymous

December 10, 2004 08:22 AM

I have contacted someone who has implemented Ken Perlin's original code. They promised to take a look. In the meantime, I will try to figure out some of this Java stuff.

Quote:Original post by Dmytry
edit: can somebody tell me why "source" box extends horisontally so much?

Good question; Very annoying. At least it only affects your post and not the whole thread.

Matthew Doucette

384

Author

December 10, 2004 08:25 AM

Anonymous Poster, above, is myself.

[Edited by - Doucette on December 15, 2004 8:25:10 AM]

Matthew Doucette, Xona Games

Matthew Doucette

384

Author

December 15, 2004 10:22 AM

For all those interested, I have started a new thread to branch off on the Java compiler/editor issue:

Java compilers/editors (which to use?)
http://www.gamedev.net/community/forums/topic.asp?topic_id=288694

Matthew Doucette, Xona Games

Matthew Doucette

384

Author

January 10, 2005 09:24 AM

I have branched off on a new thread for discussion of Perlin Noise distribution:

>>> Perlin Noise Distribution <<<

Matthew Doucette, Xona Games

2D Perlin Noise (gradient noise) range = ?

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2D Perlin Noise (gradient noise) range = ?

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