This weekend I continued working on tribal migrations. Though first I had to deal with tons of issues that I introduced last week with the polity prominence rewrite. Everything is mostly back to normal though. The only weirdness left being that now polities expand much more slowly because the new prominence update functions doesn't mesh very well with the old polity expansion event. That doesn't matter since that event and the group migration event are being replaced too with more appropriated migration events.

So, as I mentioned last week, the old cell group migration event is being split into two: The first event, which I have already started working on, will handle unorganized bands moving across the map. It will be mostly a simplified version of the old event that strips away any of the former's prominence transfer mechanics to prevent polities from expanding through that event. This migration algorithm is rather "mindless" and only seeks to spread groups using a logic that favors moving into cells for which the migrating bands have strong adaptations, but doesn't completely prevent groups from moving into inhospitable territory every now and then.

The second migration event will only happen to cells that have polity (tribe) prominences and will only migrate bands that are part of a tribe. These bands will move into neighboring cells just like with the old event. The difference will be that the logic that decides migration direction will be highly influenced by the intentions of the tribe to which the bands belong. The first consideration will be if the cell the bands want to move into is part of a region that the tribe is attempting to colonize. If it isn't, then it will consider instead how much pressure there is for the tribe to move outside of its current region (how overpopulated the entire region is). This event might even force a tribe to abandon cells entirely if these are too inhospitable to support large organized groups or if the tribe is being pushed out by neighboring tribes (which will be fleshed out once I start working on tribal aggression).

Next week, I'll finish work on the new unorganized band migration event and start working on the tribal migration event. Once I get those two working, I will phase out the old events. Though a lot of testing will be needed to make sure things work as expected.