Talk:Perlin noise: Difference between revisions

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Revision as of 17:49, 5 March 2014

Correctness

The D implementation generates exactly the same outputs of the Java version. I have used the D code to generate this image (with the grayscale code visible in the D entry): http://oi62.tinypic.com/2pt9flx.jpg

Is such image correct? Isn't a correct Perlin noise image without sharp borders, like this?

http://4.bp.blogspot.com/-u4wfD21sIvU/UsI85U78XYI/AAAAAAAAAx8/NG2fEzYjTUA/s1600/perlin2.png

Your image is not correct. The perlin noise has a range between -1 and 1, and you use this to convert it into an unsigned byte:

Gray(cast(ubyte)(p * 256))

Try this:

Gray(cast(ubyte)((p+1)/2 * 256))

Also, your image will look smoother than the example you found on blogspot.com, since this imag is made with several octaves.

--Grondilu (talk) 17:49, 5 March 2014 (UTC)

@@ Line 5: / Line 5: @@
 http://4.bp.blogspot.com/-u4wfD21sIvU/UsI85U78XYI/AAAAAAAAAx8/NG2fEzYjTUA/s1600/perlin2.png
+:Your image is not correct.  The perlin noise has a range between -1 and 1, and you use this to convert it into an unsigned byte:
+:<code>Gray(cast(ubyte)(p * 256))</code>
+:Try this:
+:<code>Gray(cast(ubyte)((p+1)/2 * 256))</code>
+:Also, your image will look smoother than the example you found on blogspot.com, since this imag is made with several octaves.
+:--[[User:Grondilu|Grondilu]] ([[User talk:Grondilu|talk]]) 17:49, 5 March 2014 (UTC)