
I'm still not sure if it's best to store 2, 3 or 4 bits of info per square.
The problem with 4 bits/sq (hence 32 bits per ray) is that the LUT would be too large to fit into RAM, but unlike in 2006, it would be small enough to fit onto an SSD, and it could probably be hashable in RAM, as only a small part of it would be needed in the search from a certain position.