Posted July 13, 2024 by Teknologicus
I'm using a stateless pgc hash function in 3D coordinate space to generate noise for my procedurally generated blocks. In case anyone is curious about the code, here are pcg hash functions for 1D, 2D and 3D in integer coordinates written in C++
inline constexpr uint32_t pcgHash(uint32_t x) { uint32_t state = (x * 0x2C9277B5u) + 0xAC564B05u, word = ((state >> ((state >> 28) + 4)) ^ state) * 0x108EF2D9u; return word ^ (word >> 22); } inline constexpr uint32_t pcgHash(uint32_t x, uint32_t y) { uint32_t h = pcgHash(x) + pcgHash(y); return h ^ (h >> ((x % 15) + 1)); } inline constexpr uint32_t pcgHash(uint32_t x, uint32_t y, uint32_t z) { uint32_t h = pcgHash(x) + pcgHash(y) + pcgHash(z); return h ^ (h >> ((x % 15) + 1)); }
and what the 2D noise it generates looks like via shadertoy
https://www.shadertoy.com/view/Mcsyz4
Update: The following code yields good looking noise and is slightly faster
inline constexpr uint32_t pcgHash(uint32_t x, uint32_t y) { return pcgHash(pcgHash(y) + x); }