An unexpected use of hash functions

Reviewing some pages, I found the following bit in this page.

On hashing: a sore point in mount.c, the fractal mountain generator, has been its hashing function. Mark VandeWettering has provided a great hashing function by Bob Jenkins. To show what a difference it makes, check out images of models made with the original hash function with a large size factor, replacement hash function I wrote (still no cigar), and Jenkins' hash function.

Another reason why hash functions should be written carefully.