Constant time stateless shuffling and grouping(ea.com)

50 pointsby jasondavies3 anni fa5 comments

Constant time stateless shuffling and grouping

https://www.ea.com/seed/news/constant-time-stateless-shuffling

5 comments

It is the same method that I use in clickhouse-obfuscator: https://github.com/ClickHouse/ClickHouse/tree/master/program...

bhickey3 anni fa

> The round function can use anything, including destructive operations, so a nice fast hash like PCG is a good choice.

PCG isn't a hash. Maybe they meant FNV?

karmakaze3 anni fa

I searched "PCG Hash" and found this as part of a shader:

  uint PCGHash()
  {
    rng_state = rng_state * 747796405u + 2891336453u;
    uint state = rng_state;
    uint word = ((state >> ((state >> 28u) + 4u)) ^ state) * 277803737u;
    return (word >> 22u) ^ word;
  }

This doesn't look like FNV or any other hash function I know.

bhickey3 anni fa

How odd. That isn't even a hash function!

Atrix2563 anni fa

Here's the source. Nathan Reed references a jcgt paper, which references a paper form 2012. https://www.reedbeta.com/blog/hash-functions-for-gpu-renderi...