FastNoise2 VS manta-ray

Note the notice at the top of the readme, the author is replacing that library with FastNoise2 which is also SIMD enabled, although the library as a whole is still a work in progress, it claims to have superior performance.

I am using a very fast [noise library](https://github.com/Auburn/FastNoise2). After generating a 64x64 area of noise I turn that into a 64x64x64 array of voxel byte data. I then use my own version of this [greedy meshing algorithm](https://github.com/cgerikj/binary-greedy-meshing).

There's a nice GDC talk about noise functions here, and if you're interested in trying things out there's an Open Source noise library written by a No Man's Sky developer here.

Very cool! Have you considered using FastNoise2 as a noise source? It's SIMD optimized C++ https://github.com/Auburn/FastNoise2 But they've made C# bindings so there's less native legwork: https://github.com/Auburn/FastNoise2Bindings

Let Simplex 3D use its same gradient generator, but use 1/2 instead of 1/6 for the noise's unskew constant. This rotates the axis angles of the gradient set out of the main noise evaluation planes. I haven't implemented+run this myself, but it is implemented here in FastNoise2 (SIMD library), and I simulated the difference using OpenSimplex2 in this image (bottom with change). The result isn't perfect, but it's much nicer I think. After making this change, either set scale to 32.69428253173828125 to make a proper -1 to 1 range, or bake it into the gradient table directly.