Personal site of Wouter Lindenhof


Procedural story


A little while ago I was meeting a good friend of mine and we had a lot of things to talk about. For one he had just returned from Kenya and he had a lot to show and tell and the things he told me where amazing. But as the day went one, we almost always seem to come back to one subject: Games and developing of games. Funny enough the two of us have almost had the same kind of ideas.
Both of us are developing games in our free time and both have the idea of trying to make as much as possible procedural generated. One of the things we are both interested in is creating the story. While I look for an infinite solution (where the player can play forever and has an interesting storyline) he has a more pragmatic approach.
As we discussed procedural generated stories he pointed out that a story teller needs to tell his audience what happens where and when (not to be confused with why). This triggered a thinking path I had not yet explored. Until then I had simply assumed events happen in a certain order. When a user is playing a computer game he will grow a certain emotional attachment to the player. Emotions in a story are important. For example Romeo and Juliet is a story about hate between families, love between two person and has a lot of betray. Romeo and Juliet is considered one of the classic romantic stories and by some it is considered one of the most romantic stories ever written.
So after the talk and some thinking a procedural story generator could be written as a system that tries to move from emotion to another emotion both for individuals as a culture. To give yet another example: The player gets betrayed by a general and while he was betrayed the general does end the war (and the country he fought for sees him as a hero), while at the other side (the defeating side) wants to see the general death. You now have four elements: The player, the general, the winning country and the losing country. The player is angry as he is betrayed. The general is content and pleased as he is being seen as hero. The winning country feels superior to the losing country and the losing country feels disgust towards all other elements. See the diagram.

At this point the computer needs to "write" the next part of the story. The computer could now plot a new scheme by just adding or removing some story elements. The player could for example become the leader of the rebellion or he could join the general as one of his right-hand leaving his feelings of betray or he could kill the general and become the new general. In this case I want to add another character say the princess of the winning country and make the player the leader of the rebellion. The princess finds out that the generals betray and for some reasons she encounters the player and they fall in love with each other. Yet they can't be with each other as one country hates the other ruler. The general at this point hates the player. The graph might be clearer.

Moving forward we arrive at a point in the story where the player and the princess are married and they rule both countries. The general is now hated by all. And here is another graph.

For the story generator the only thing is how the possible futures of all elements could be. Once he knows the possible futures all it has to do is create "story chapters" which move the story toward the possible features. If needed a chapter could have a branch which excludes one of the possible features, for example the player kills the general before the princess was able to find out about the betray of the player so she never finds out the wrong he did and therefore never encounters the player.
Of course a lot more thought needs to go in this, but it solved for the procedural "writers-block".

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