So I’ve been working more and more toward editable terrain.  Still not quite there yet, but am finally getting rather close.  I’ve now set up a couple of key steps towards editable terrain.  First, the subregions (and regions, for that matter) which I’ve mentioned before now know about their neighbours.  Ever since dropping the “grid”-based region approach that I used in MMORPG Tycoon 1 and 1.1, regions haven’t been able to know what other regions bordered them, simply because they were irregular;  when all you have is a big list of shapes, it can be difficult to tell which ones share borders!  But that’s now been sorted out.

This will be important for terrain editing, for smoothly blending from one terrain type into another, across subregion boundaries.

I’ve also today set up subregions to be able to specify a different style than that of their parent region.  In the screenshot here, I’m standing inside a hilly-grasslands subregion, looking towards two rolling-mountain-tundra subregions.  (the blending between regions isn’t implemented yet, which is why you can see sharp cliffs between the different subregions)

Next step will be blending terrain between subregions.  I’ve got a pretty good idea of how that’ll work.  Next after that will be actually regenerating the terrain data when the player adjusts the subregions.