Procedural Generation is the Future

Jan 3rd 2015
Tagged: Programming

I 've been noticing a trend in gaming recently towards procedurally generated content. Minecraft has it, Starbound and Terraria have it, and randomized rogue-likes are running amok. No longer do we just play the same level over and over again until we memorize it well enough (remember Super Mario Bros?). The new gaming paradigm is one of discovery and adventure! While I know from experience that meticulously planned dungeons and carefully crafted levels can deliver an amazing experience, there are several reasons as to why I think the trend towards procedurally generated content is a good one.

These are some of the primary benefits I've discovered in using procedural generation:

  1. PG Allows you to produce near unlimited amounts of content.
  2. PG Saves disk space.
  3. PG Spikes Creativity

1) pg allows you to produce near unlimited amounts of content.

If Minecraft or Terraria had been built by hand with only one world to explore, people would have figured out its tricks, read about them online, figured out the quickest way to their goal and would be done with them by now. A key part of what makes these games special is that they have amazing replay value because the whole world changes every time you start over. You can explore as far as you like, the developer didn't need to put bounds on the world because the computer can just follow its rules and continue to create! A procedural generation approach lets your world create and discover itself!

2) pg saves disk space.

One amazing and mostly unintended benefit of generating your world on the fly is that an entire game world can be represented as a seed value of just a few letters or numbers. If a part of the world hasn't been altered, then any given section of that world can be regenerated as needed from the seed value. Since math doesn't change, it will turn out the same every time. In a world like Minecraft where the world morphs and changes, only the differences from the generated world need to be remembered and can be applied like a patch. This means that in a game like No Man's Sky with 18 quintillion planets, every one of those planets can be remembered with a single seed value taking up no more than a few bits.

3) pg spikes creativity

When things are randomly generated, sometimes they don't always go according to plan. While this is one of the bigger frustrations with creating this sort of game, it's also one of the best sources of inspiration. Did a bug in your system accidentally create an entire city under the ocean biome? Cool, that might be fun! Uh-oh, gorillas are accidentally spawning all over the north pole, what would a tribe of arctic apes look like? The unexpected nature of generators like this can spark some interesting ideas. I can't remember how many times I've been cruising through Spelunky when something so beautifully unplanned causes my run to come to a hilarious and unpredictable demise.

Case Study

Let's examine two cases, that of Assassin's Creed and that of No Man's Sky, which is unreleased at the writing of this article, however most of its design principles have been announced through various developer interviews. Assassin's Creed is made by Ubisoft, a corporate giant; ballpark estimates for the number of employees working on Assassin's Creed IV: Black Flag range between 900 and 1000 people. In the other corner we have Hello Games, a team of less than a dozen people who are developing No Man's Sky, a far reaching game about space exploration that according to the developers could have as many as 18 quintillion possible planets. How is it that it takes a team of over 900 people to craft one world, when a team of 10 can craft 18 quintillion? It's a matter of where they've invested their effort.

Ubisoft is using a more traditional development paradigm. They are designing their world by hand, carefully crafting graphical assets to fit that world as it is designed. This means that every window, building, nook and handhold are intentionally placed, by hand, in spots that a designer chose. This method, while effective, is clearly time consuming and can sometimes seem too contrived.

Hello Games on the other hand have decided to leverage the full power of their paradigm and have decided to put their hard work into creating a clever system that will do the rest of their work for them. They decided that instead of crafting worlds, they would create a world-crafter. The initial work-load to do this is substantial, but the payoff is that now they can create as many worlds as they like with little effort, able to tweak their algorithm as they go along.

The take-home point here isn't that every game should be using procedural generation, but rather that every developer should at least consider whether it's appropriate for their current use case. Who knows, could end up saving you a ton of time and adding some awesome new features.

Cheers everyone!