What you're describe is sort of the first and last steps. As I understand it, the solution involved comparing the pattern of sand in the pack world (that they figured out from the picture) against all possible seeds.
Doing all the initial detective work allowed them to compute the xyz coords in the world, which gives the location to run the simulations.
The whole thing was abstracted away, you don't need to run Minecraft at all (so it's not like they're rending billions of images), just the function that generates the sand noise. This got written as a parallel cuda kernel and they just threw iron at it.
That then gave the 700k possible matches which were searched more thoroughly.
The matching function is very simple, it compares the generated Perlin noise to a fairly small template and as soon as there's a mismatch, it stops early. Most of the complexity in the kernel is generating the noise from a seed.
Doing all the initial detective work allowed them to compute the xyz coords in the world, which gives the location to run the simulations.
The whole thing was abstracted away, you don't need to run Minecraft at all (so it's not like they're rending billions of images), just the function that generates the sand noise. This got written as a parallel cuda kernel and they just threw iron at it.
That then gave the 700k possible matches which were searched more thoroughly.
The matching function is very simple, it compares the generated Perlin noise to a fairly small template and as soon as there's a mismatch, it stops early. Most of the complexity in the kernel is generating the noise from a seed.
https://github.com/minecrafthome/pack-sand-reversal/blob/309...