title: How to generate a seed from an xy coordinate
body: <p>Iv'e been working on a perlin script but have been having problems with creating simple pseudo random values.</p>
  
  <p>I need to be able to create a seed value from an xy coordinate but x+y has obvious problems with recurring values. Also they go into negative space so x^y doesn't work.</p>
  
  <p>Sorry if this has been already answered somewhere else but either I didn't understand or couldn't find it.</p>