Timon Michel EinDev

## Unity-XORShift.md

      
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                macklinb
                / Unity-XORShift.md
            
            
              Created
              February 25, 2021 11:26
            
              
                C# implementation of UnityEngine.Random with (almost) 1-to-1 parity
              
          
    This is a partial C# implementation of UnityEngine.Random with (almost) 1-to-1 parity.
Unity uses Xorshift for psuedorandom number generation. In particular Xorshift128, which uses a state consisting of four unsigned 32-bit integer values. The state is initialized in UnityEngine.Random.InitState using a signed 32-bit integer seed, which is shuffled around with a technique similar to the way a Mersenne Twister is initialized.
This has been tested as far back as Unity 4.7.0f1, and as recent as Unity 2020.1.17f1.
Notes


Huge thanks to MoatShrimp for figuring out how Unity initializes the Xorshift state parameters in InitState, and floating point generation.
C# - As below. Values may differ in .NET 5.0, but thankfully Unity doesn't yet support that.
JavaScript - Check out MoatShrimp's JS implemention (and neat Undermine loot lookup tool) here: