Convert some ints into a byte array without allocations?

[Samson Smith via Digitalmars-d-learn]

I'm trying to make a fast little function that'll give me a 
random looking (but deterministic) value from an x,y position on 
a grid. I'm just going to run each co-ord that I need through an 
FNV-1a hash function as an array of bytes since that seems like a 
fast and easy way to go. I'm going to need to do this a lot and 
quickly for a real time application so I don't want to waste a 
lot of cycles converting data or allocating space for an array.

In a nutshell how do I cast an int into a byte array?
I tried this:

byte[] bytes = cast(byte[])x;
Error: cannot cast expression x of type int to byte[]

What should I be doing instead?