Danl Slides

8/12/2019 Danl Slides

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Racket on the Playstation 3? Its not what you

think...

Dan Liebgold

Naughty Dog, Inc.Santa Monica, CA

RacketCon 2013
http://find/http://goback/


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Motivation

In games, programmers create code; artists, designers,

animators, sound designers create data We often want to create data like we create code

Effect definitions, animation states & blend trees, event &gameplay scripting/tuning, sound metadata

We want powerful abstractions, flexible syntax, and

language well matched to each domain Domain Specific Languages to the rescue!


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Motivation







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Motivation





http://find/


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Motivation


animators, sound designers create data

We often want to create data like we create code Effect definitions, animation states & blend trees, event &

gameplay scripting/tuning, sound metadata


http://find/


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Motivation


animators, sound designers create data

We often want to create data like we create code Effect definitions, animation states & blend trees, event &

gameplay scripting/tuning, sound metadata


http://find/


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Scheme

We had experience using Common Lisp before to create

our own implementation language (GOAL) Lisp supports creating data like code

We built DCin Racket Used Racket (MzScheme initially) because its a good Lisp,

is open source, and has quality libraries and

implementation
http://find/


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Scheme





implementation
http://find/


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Scheme





implementation
http://find/


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Scheme





implementation
http://goforward/http://find/http://goback/


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How?

Racket program that evaluated typed Racket-ish code

that generates data usable by C++ runtime.

Usage of syntax was the prime enabler of rapid DSL

development, but also a source of much inefficiency and

confusion.

Error reporting was slow to develop, since it required

careful usage of syntax info, which was difficult andconfusing.
http://find/


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How?





confusion.


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How?





confusion.


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Architecture

E l
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Example

Lets define a player start position:

(define-export *player-start*(new locator

:trans *origin*:rot (axis-angle->quaternion *y-axis* 45)

))

S i h
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Start with some types

(deftype vec4 (:align 16)

((x float)

(y float)

(z float)

(w float :default 0)

))

St t ith t
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Start with some types

(deftype vec4 (:align 16)

((x float)

(y float)

(z float)

(w float :default 0)

))

struct Vec4

{

float m_x;

float m_y;

float m_z;

float m_w;

};

T ti d


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Types continued

(deftype quaternion (:parent vec4)

())

(deftype point (:parent vec4)

((w float :default 1)))

(deftype locator ()

((trans point :inline #t)

(rot quaternion :inline #t)

))

T pes contin ed
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Types continued

(deftype quaternion (:parent vec4)

())


((w float :default 1)))

(deftype locator ()

((trans point :inline #t)

(rot quaternion :inline #t)

))

Types continued
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Types continued

(deftype quaternion (:parent vec4)())


((w float :default 1)

))

struct Locator

{

Point m_trans;

Quaternion m_rot;};

Define a function
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Define a function

(define (axis-angle->quat axis angle)

(let ((sin-angle/2 (sin (* 0.5 angle))))

(new quaternion

:x (* (-> axis x) sin-angle/2):y (* (-> axis y) sin-angle/2)

:z (* (-> axis z) sin-angle/2)

:w (cos (* 0.5 angle))

)))

Define some instances
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(define *y-axis* (new vec4 :x 0 :y 1 :z 0))

(define *origin* (new point :x 0 :y 0 :z 0))

(define-export *

player-start*(new locator

:trans *origin*

:rot (axis-angle->quaternion *y-axis* 45)

))

http://find/


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(define *y-axis* (new vec4 :x 0 :y 1 :z 0))

(define *origin* (new point :x 0 :y 0 :z 0))

(define-export *player-start*

(new locator

:trans *origin*

:rot (axis-angle->quaternion *y-axis* 45)

))

How we use these definitions in C++ code
http://find/


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How we use these definitions in C++ code

...

#include "dc-types.h"

...

const Locator * pLoc =DcLookupSymbol("*player-start*");

Point pos = pLoc->m_trans;

...


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The Last of Us on the Playstation 3
http://find/


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The Last of Uson the Playstation 3

16 programmers on the game project

20 designers

100 artists & animators

6000 DC files

120Mb of DC source, 45Mb of DC target binary files Dynamically loaded into about 5Mb of managed heap

space

http://find/


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20 designers


6000 DC files


space

http://find/


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20 designers


6000 DC files


space

http://find/


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20 designers


6000 DC files


space



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20 designers


6000 DC files


space



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y


20 designers


6000 DC files


space

Experience
http://find/


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p

Racket power, library support a big win

Syntax transformation source location and performance

hindered us

S-expression based language a tough sell to industryprogrammers, as well as designers, and non-technical

types ...especially when paired up with Emacs as the editing

platform. Although once learnt many programmers and designers

were expand and extend the language effectively

Functional nature of the system is a big win, allowing datato be flexibly transformed to just the right runtime

representation

Experience
http://find/


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p



hindered us






representation

Experience
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p



hindered us






representation

Experience
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hindered us






representation

Experience


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hindered us






representation

Experience
http://find/


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hindered us






representation

Questions?
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