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Raymarching Beginners' Thread

category: code [glöplog]
las: ...but it's not "OK", it's horrible :P
added on the 2011-03-17 18:07:46 by kusma kusma
oh, and simplex noise != perlin noise. It's a similar kind of noise, but it's not perlin noise.
added on the 2011-03-17 18:09:18 by kusma kusma
Oh yeah, that one looks really horrible... But it will be ok for 4k ;)
Hmm maybe I screwed something up... Paulo - could you also test the original noise by decipher (also to be found in the toolbox thread)?
added on the 2011-03-17 19:53:52 by las las
+ that simplex noise would slow down the raymarching even more horribly.
added on the 2011-03-17 19:56:22 by las las
las: the quality of the noise isn't important if you sum many octaves (fractal plasmas etc), but if you have few octaves then it looks really bad ;)
added on the 2011-03-17 19:58:11 by kusma kusma
Perlin noise and Perlin simplex noise is not just a blurred noise texture.
http://webstaff.itn.liu.se/~stegu/TNM022-2005/perlinnoiselinks/perlin-noise-math -faq.html
Visually the interpolation points are uniformly distributed but not aligned in a point lattice.
I'd prefer the perlin interpolated algo. It looks smoother.
added on the 2011-03-18 01:31:31 by yumeji yumeji
It looks nice and all, but it is not suitable for 4k...
added on the 2011-03-18 09:42:29 by raer raer
Perlin noise in 4k: Use HLSL's noise-function in a texture shader. Texture shaders are implemented on the CPU, and the noise-function actually works then. It's a bit tricky to get the texture to tile, but can be done.
added on the 2011-03-18 09:53:50 by kusma kusma
i believe that's how Himalaya/TBC was done, right?
added on the 2011-03-18 10:13:38 by iq iq
Is there anyway to get that to work in OpenGL? Or is it better to just create a noise texture on the CPU?
added on the 2011-03-18 10:32:44 by raer raer
Quote:

Perlin noise in 4k: Use HLSL's noise-function in a texture shader. Texture shaders are implemented on the CPU, and the noise-function actually works then. It's a bit tricky to get the texture to tile, but can be done.

We used that in 2007 already. It's something like 3 function calls with D3DX.
But I prefer having everything in one shader.
added on the 2011-03-18 10:48:18 by las las
+Rendermonkey supports texture shaders (tx_1_0) - so you can use that and generate 3D textures with texture shaders.
added on the 2011-03-18 10:49:49 by las las
http://via.pulsene.ws/15uWX Did you guys check that noise ?
added on the 2011-03-18 11:28:36 by p01 p01
p01: plz, read the context. that's exactly what spawned the noise-discussion :P
added on the 2011-03-18 11:45:12 by kusma kusma
perlin!=simplex&&simplex!=perlin
added on the 2011-03-18 12:13:28 by unc unc
"Interactive Modeling of Implicit Surfaces using a Direct Visualization Approach with Signed Distance Functions"

http://cg.ibds.kit.edu/downloads/IntModelingSDF.pdf

hmm...
added on the 2011-03-18 18:59:48 by hornet hornet
Sorry, super duper busy with the baby. I was indeed missing some context and tons and tons of sleep :p
added on the 2011-03-18 19:00:20 by p01 p01
p01, you have the baby?
added on the 2011-03-18 19:04:07 by Pirx Pirx
[offtopic] Yes. She's 3.5 months old and amazing ... and demanding like all babies I guess. I took parental leave + holidays for her first year. Hopefully I'll manage to be a bit productive during this period. [/offtopic]
added on the 2011-03-18 19:10:53 by p01 p01
Great news, congratulations!
added on the 2011-03-18 19:16:08 by Pirx Pirx
What a cool paper
Congratulations p01!
My baby is 9 months now.
Understand you perfectly about the sleep issue LOL
hornet: Ohh nice at least one of the guys is a demoscener.... remember parsec? ;)
Basically that paper does introduce nothing really new and the fragment shader source example is not really helpful at all.
The approach they propose is more or less obvious. Seems as if someone over there reads this thread... ;)
added on the 2011-03-19 03:08:33 by las las

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