Voronoi map generation in Civilization VII

Summary

Hello Civ fans! Ken Pruiksma, Senior Graphics Engineer at Firaxis Games, here to share some behind-the-scenes updates on map generation.When Civilization VII first shipped, the map generation technique we used focused on ensuring balanced play while following some new gameplay rules around things like Deep Ocean and Distant Lands. This technique, which has its roots in previous Civ games, created fair maps, but also made them predictable. This caused the exploration phase of the game to be potentially less rewarding (which is a problem when the first X in 4X is Explore!) We heard from you that maps felt too repetitive, and we agreed. Something else we heard loud and clear from the community is that the straight-edged coastlines that could occur between the two major halves was hindering the play experience. Part of the fantasy of Civ is that you're playing an alternative history of Earth, and when the maps don't feel plausibly Earth-like, it detracts from the experience (outside some exceptions like perfectly balanced multiplayer where you're opting into a mirrored game).So, we've made some big updates with 1.2.5. We wanted map generation that felt more natural and less repetitive, while still keeping balance in mind where it matters. Out of that work came two brand new map types to choose from: Continents and Islands (two large continents, with islands) and Pangea and Islands (one large continent, with islands). Both are built on an entirely new technique: Voronoi map generation. VORONOI MAPSI'm a graphics engineer, which means I spend most of my time making beautiful pixels, but I've always had a soft spot for procedural generation and the algorithms that drive it. When the chance came up to help the gameplay team with map generation, I couldn't resist. I had an idea about using Voronoi diagrams to dynamically grow landmasses using some rules. After throwing a quick test together, the idea showed promise. Without getting too technical, the Voronoi technique comple...