eMuse

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eMuse

• Rapid Screenplay Prototyping Language

Mark Ayzenshtat Elena Filatova Kristina
Holst Vlad Shchogolev
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Motivation

• Screenplays can succeed on paper but fail on
  stage.
• Screenplay is the natural blueprint or source
  code for a play.
• Writers and directors couldnt care less about
  loops, functions, scope, etc.

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Overview

• eMuse is 2 things
• a language
• screenplay-like syntax
• allows more-or-less free-form English
• a 2D animation framework
• simple stick figures with superimposed images
• extensible custom behaviors

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Source Structure

• Title / Author
• Definitions
• Characters
• Props
• Settings
• Each of these is typed (e.g. Romeo
  LovesickTeenager)
• Exposition
• Dialogue
• Actions

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Syntax

• As close to the syntax of a play written in
  natural language as possible, e.g.
• Authors names
• All possible formats can be accepted
• Stephen A. Edwards, Sasha, etc
• Action format might include any combination (all
  combinations are parsed by one rule)
• Direct object
• Preposition
• Indirect object
• Adverb
• Francisco (appears on stage), Bernardo (takes
  sword),
• Francisco (appears away quickly)

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Semantics

• eMUSE has quite simple semantics
• No scoping
• All variable names must be unique

Romeo ltYoung noble guygt
Romeo ltOld peasantgt
Juliet (kisses Romeo)
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Semantics (contd)

• eMUSE has quite simple semantics
• Characters and Props mentioned in the actions
  should be defined

Character Romeo ltYoung noble guygt Prop
Book ltThe Dragon Bookgt
Definitions
Juliet (hits Romeo with Book)
Exposition
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Compiler

• Two halves
• Lexer, Parser, Semantic Checker
• Back end OutputGenerator
• Just an API an interface lots of different
  implementations possible
• Default Implementation Java source code

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Java Output Generator

• A Java Model API
• Models classes, methods, modifiers, etc. as Java
  objects.
• Not This writeSource(public class Foo )But
  This Class c new Class(Foo) c.addModifier
  (Modifier.kPublic)
• sourceWriter.write(c)
• Advantage generated source is readable,
  consistent

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Java Output Generator (contd)

• What does the generated Java source do when
  compiled and run?
• Answer Animates the screenplay using our
  Animation Framework

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Animator Design

• Two basic entities derived from parse tree
• Actions
• Stage objects
• Actions occur over discrete time intervals
• Stage objects are organized in a class hierarchy

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Animator Design (contd)

• Affine Transformation
• Composition of matrix multiplications define
  transformation of local to global coordinate
  system.
• used to construct scene graph in which individual
  objects can be manipulated from any node in the
  scene graph

Global
Local
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Actual Screenshot
Dubya shares a serene moment with Prof. Edwards.