I'm developing one-dimensional terrain generation in my game.
I give the program a seed and based on that I need to be able to walk forwards and backwards on a line that is drawn between a series of points with the same interval but a different height.
So I need a random number generator where I can request both the next and previous number from a given state.
Most PRNGs I can find generate numbers only in the forward direction, and have no ability to operate in reverse. Is there a random generator I can use that can run both forwards and backwards?