Reversing Factorio's RNG

https://gegell.github.io/posts/factorio-rng/

If we take a look at how the function is implemented in the game we can see that it basically just takes the RNG roll and compares it against some thresholds. It stops as soon as it finds a threshold which is no longer beaten by the roll.

This means that each craft which involves quality rolls will take exactly 1 RNG call. And for each call we can compute the expected quality level by just comparing against all the thresholds, which stay constant during the game. Thus they can be precomputed in-game with some arithmetic combinators.