1. eMuse “Rapid Screenplay Prototyping Language” Mark Ayzenshtat Elena Filatova Kristina Holst Vlad Shchogolev

2. Motivation Screenplays can succeed on paper but fail on stage. Screenplay is the natural blueprint or “source code” for a play. Writers and directors couldn’t care less about loops, functions, scope, etc.

3. 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

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

5. 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)

6. Semantics eMUSE has quite simple semantics No scoping All variable names must be unique Romeo: Juliet: (kisses Romeo) Illegal

7. Semantics (cont’d) eMUSE has quite simple semantics Characters and Props mentioned in the actions should be defined Juliet: (hits Romeo with Book) Character Romeo: Prop Book: Definitions Exposition

8. 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 Default eMuse Compiler ScreenplayJava

9. 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

10. Java Output Generator (cont’d) What does the generated Java source do when compiled and run? Answer: Animates the screenplay using our Animation Framework

11. 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

12. Animator Design (cont’d) 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 Stage Character Left ArmRight Arm Left LegRight Leg Head Speech Balloon Body Prop Local Global

13. Dubya shares a serene moment with Prof. Edwards. Actual Screenshot