How to force certain biomes to only spawn adjacent to certain other biomes?

[freeradicalx]

I'm in the planning stages for a mod that intends to eventually convert the Overworld dimension into a modern "human-influenced" landscape of wilderness, rural, suburban and urban biomes that flow seamlessly into one another ("Urban" biomes would only spawn next to other urban biomes or suburban biomes, suburban biomes would provide broad buffers between urban and rural biomes, and large rural biomes would eventually give way to occasional vanilla-style wilderness biomes). Generating the structures necessary for these biomes has already been taken care of, but I currently have no clue how to create this wilderness->urban->wilderness gradient that would effectively force certain biomes to spawn next to other certain biomes. I know this can be done because, well, beaches. I just don't see in the source how it happens. Can anyone here explain a procedure for getting this to work?

 

As a side note, I've read that world generation is based on a combination of lots of scaling/fractalization (X and Z) and perlin noise (Y, some X and Z), which seems to suggest that the shapes of biomes can't easily be controlled. Is there a way around this? Is there any easy way of getting a biome to spawn as a rough rectangle or other polygon?

 

Thanks, any answers much appreciated.

[Mazetar]

I guess that would be by doing it all by yourself?

code a generation sequence which you run after/insteadof the original one for the selected area(s)?