Lecture 1 CS148/248 UC Santa Cruz School of Engineering January 7, 2009

UC SANTA CRUZ Class Mechanics  Syllabus:  Access to secure materials  User Name: cmps148  Password: N2I3Nz

UC SANTA CRUZ What is interactive narrative?  Somehow combine “interactivity” and “story”  What is interaction?  What is story?  The two terms seem to be in conflict “I won't go so far as to say that interactivity and storytelling are mutually exclusive, but I do believe that they exist in an inverse relationship to one another… Interactivity is almost the opposite of narrative; narrative flows under the direction of the author, while interactivity depends on the player for motive power…” Ernest Adams in Gamasutra

UC SANTA CRUZ The holy grail of interactive narrative?

UC SANTA CRUZ Live in a storyworld

UC SANTA CRUZ Questions about the holodeck  Are all holodeck experiences story?  What are the limitations of a pure, first-person, realist perspective?  Are there stories for which it is inappropriate (or at least unlikely) for the player to be the protagonist?  Let’s look at other examples that have been called interactive stories

UC SANTA CRUZ Example 1

UC SANTA CRUZ Example 2

UC SANTA CRUZ Example 3 ZORK I: The Great Underground empire Copyright (c) 1981, 1982, 1983 Infocom, Inc. All rights reserved. ZORK is a registered trademark of Infocom, Inc. Revision 88 / Serial number West of House You are standing in an open field west of a white house, with a boarded front door. There is a small mailbox here. >open mailbox Opening the mailbox reveals a leaflet. >read leaflet (taken) "WELCOME TO ZORK! ZORK is a game of adventure, danger, and low cunning. In it you will explore some of the most amazing territory ever seen by mortals. No computer should be without one!" >

UC SANTA CRUZ Example 4

UC SANTA CRUZ Example 5

UC SANTA CRUZ Unpacking “interaction” and “narrative”  First half of course will focus on understanding what we might mean by “narrative” and “interaction”  Given the previous examples, how can we move beyond spouting opinions towards having a more deeply informed understanding of interactive storytelling  To many of you, this first half of the course may feel like a humanities class  But having a deeper understanding of storytelling and designing for interaction is necessary for understanding technical approaches

UC SANTA CRUZ Artificial Intelligence and Story  Story generation  Story understanding  Drama Management  Autonomous Characters

UC SANTA CRUZ Story generation I: Morphemes & grammars  Morphemes – story events or “functions”  Vladimir Propp analyzed Russian folk tales  Example morphemes: The hero leaves home, the hero is given a difficult task, the hero defeats the villain  Grammars – hierarchic combination rules  Story grammars – use story functions by analogy to linguistic elements

UC SANTA CRUZ once upon a time there lived a dog. one day it happened that farmer evicted cat. when this happened, dog felt pity for the cat. in response, dog sneaked food to the cat. farmer punished dog. Joseph story generator – R. Raymond Lang story  setting + episodes episodes  episode + episodes episode  story_event + emotional_response + action_response Sample output & story grammar

UC SANTA CRUZ  Model authorial knowledge beyond story structure  Examples: Authorial goals, plans, knowledge about the world Story generation II: Author simulation

UC SANTA CRUZ Example character in Universe Name: Liz Chandler Marriages: Don Craig [1980] Tony Dimera Stereotypes: Actor, Knockout, Socialite, Party-goer Trait modifiers: (Sex F) (Age young-adult) (Wealth 3) (Promiscuity -3) (Intelligence 3) Description: Wealth 8Promiscuity 3Competence NIL Niceness 0Self-Conf 6Guile 7 Naiveté 7Moodiness 6Phys-Att 7 Intelligence 7Age young-adultSex F Goals: (Find-Happiness Become-Famous Meet-Famous-People)

UC SANTA CRUZ Example plot fragment Plot fragment: forced-marriage Characters: ?him ?her ?husband ?parent Constraints: (has-husband ?her) (has-parent ?husband) ( < (trait-value ?parent ‘niceness) –5) (female-adult ?her) (male-adult ?him) Goals: (churn ?him ?her) {prevent them from being happy} Subgoals:(do-threaten ?parent ?her “forget it”) (dump-lover ?her ?him) (worry-about ?him) (together * ?him) (eliminate ?parent) (do-divorce ?husband ?her) (or (churn ?him ?her) (together ?her ?him))

UC SANTA CRUZ Minstrel’s Architecture

UC SANTA CRUZ Application of TRAM:Generalize-Constraint  TRAM:Generalize-Constraint  Transform: select and generalize a feature (call it $generalized-feature) of the scene specification. Use this new scene specification as an index for imaginative recall.  Adapt: adapt the recalled solution to the current problem by adding $generalized feature back to the recalled scene

UC SANTA CRUZ Interactive Drama Plot structure Tension/Complexity Time Exposition Inciting incident Rising action Crisis Climax Falling action Denouement Characters Personality Emotion Self motivation Change Social relationships Consistency Illusion of life

UC SANTA CRUZ The Enemy  Author has control but  All interaction paths must be pre-coded by author  Can only make very small stories  Bits of story can’t be incrementally added Story AI: authorship and interaction

UC SANTA CRUZ Drama management  Policy for “story piece” selection  An alternative to explicitly coded links Story library Selection policy Actual sequence

UC SANTA CRUZ General interactive drama (story) architecture