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About Buckslice

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  1. Hello gamedevs, I'm making a space game in Unity, and using this implementation of 3D simplex noise for the basis of my planet generation http://cabbynode.net/downloads/Noise.cs. I'm using my own function for getting noise with octaves however, since the provided one is slightly bugged and doesn't provide good results for me. public static float fBm(Vector3 v, float seed, float scale, int octaves, bool ridged, float persistance = 0.5f, float lacunarity = 2f) { double x = v.x + seed; double y = v.y + seed; double z = v.z + seed; float total = 0.0f; float amplitude = 1f; float frequency = scale; for (int i = 0; i < octaves; i++) { total += GetNoise(x * frequency, y * frequency, z * frequency) * amplitude; amplitude *= persistance; frequency *= lacunarity; } if (ridged) { return (1f - Mathf.Abs(total)) * 2f - 1f; } else { return total; } } The main difference in my function is that the total noise value is not divided by the max possible amplitude at the end, like in the provided source. I don't like that because as the octaves go up, the high and low points of the noise kind of get averaged out and you end up with values from around -0.8 - 0.8f at 5 octaves for example. The downside of this is that my noise is no longer clamped between [-1f, 1f], so I'm looking for a way to add detail with the octaves but still have a nice range from [-1f, 1f].    Basically I want my octave'd noise to look like these pictures from the libnoise library http://libnoise.sourceforge.net/tutorials/tutorial4.html. In my version there is a lot less white and deep blue in the higher octaves compared to the original first octave. I've looked at the source but my function seems pretty much the same, nonetheless I've tinkered around with it a lot, but nothing has worked so far. Is it because I'm using 3D noise? Is there a property of perlin noise that helps with smooth octave generation that simplex lacks? From what I understood you could use any type of noise to generate these octaves (also called fractal brownian motion?). Maybe I am not applying the seed right or something.   Any help would be much appreciated, and I will make sure to post some sick screenies once I get my planets looking right. Thanks!   -Buck   ps: sorry if this is the wrong subforum, figured the math experts could help me out, hah!
  2.   Why is pZ not multiplied by currentDouble?     Thanks so much Alvaro! that was definitely the problem. I just noticed that the distortion was only happening when using the octaves function as well. I can't believe I didn't see that!   Also you're right Javier I have been just fiddling around with values to get it looking how I want. Definitely need to clean it up though. Ty for input!
  3. Hello gamedev.net,   I'm programming a 3D space game in Unity using c# and I've run into a bit of a problem with my planet generation. I have code right now that generates on icosphere and applies simplex noise to it, it looks pretty good but I'm getting weird noise striations along the side of the planet. It looks like the noise is getting stretched along parts of the planet.   I'm using this implementation of simplex noise http://cabbynode.net/downloads/Noise.cs   Here's the relevant code. it just loops through each vertex i in vertices[] which are all unit length along a subdivided icosphere and applies some noise to it. They end up ranging from about 0.85f - 1.15f afterwards and then I just scale it up for however big I want the planet to be. float random = Random.Range(100f, 1000f); for(int i = 0; i < vertices.length; i++){ float noiseDensity = 2f; Vector3 v = vertices[i]; v.Scale(new Vector3(noiseDensity, noiseDensity, noiseDensity)); float scale = .25f; float noise1 = Noise.Noise.GetOctaveNoise(v.x + random, v.y + random, v.z + random, 4) * scale; float factor = 1f - (scale / 2f) + noise1; vertices[i] = Vector3.Scale(vertices[i], new Vector3(factor, factor, factor)); } I tried sampling the noise in multiple spots and average them together to try to smooth it out but I couldn't get it looking good really. I'm quite new to noise and such but I thought if I used 3D noise it wouldn't matter what shape I applied it to, but perhaps the icosphere is the problem because you can't really map a grid to it without distortions. I really don't want to use a normal sphere though because their triangles aren't as consistent of a size. If you guys have any ideas on how I could fix this problem that would be great! I wasn't sure if this was the right forum to post on but it seemed more about the math of applying noise than about rendering or graphics. Thanks!   Here's a few pictures of how it looks:   looks good here [attachment=20446:Unity 2014-03-16 15-44-06-31.png]   turn the planet a little and you can see the weird stretching I'm talking about [attachment=20445:Unity 2014-03-16 15-45-29-03.png]   on the left it looks good but then to the right you can see the stretching [attachment=20444:Unity 2014-03-16 15-48-28-65.png]  
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