Learning Processing : a beginner's guide to programming images, animation, and interaction

472 Pages·2008·8.18 MB·English

by  Daniel Shiffman

Learning Processing
A Beginner’s Guide to Programming Images,
Animation, and Interaction
The Morgan Kaufmann Series
in Computer Graphics
Learning Processing Texturing & Modeling: A Procedural Andrew Glassner’s Notebook: Recreational
Daniel Shiffman Approach, Th ird Edition Computer Graphics
David S. Ebert, F. Kenton Musgrave, Andrew S. Glassner
Digital Modeling of Material Appearance
Darwyn Peachey, Ken Perlin, and
Julie Dorsey, Holly Rushmeier, and W arping and Morphing of Graphical Objects
Steven Worley
François Sillion Jonas Gomes, Lucia Darsa, Bruno
Geometric Tools for Computer Graphics Costa, and Luiz Velho
Mobile 3D Graphics with OpenGL ES
Philip Schneider and David H.
and M3G Jim Blinn’s Corner: Dirty Pixels
Eberly
Kari Pulli, Tomi Aarnio, Ville J im B linn
Miettinen, Kimmo Roimela, and Jani Understanding Virtual Reality: Interface, Rendering with Radiance: Th e Art and
Vaaralla Application, and Design Science of Lighting Visualization
W illiam B. S herman and A lan R.
Visualization in Medicine Greg Ward Larson and Rob
C raig
Bernhard Preim and Dirk Bartz Shakespeare
Jim Blinn’s Corner: Notation, Notation,
Geometric Algebra for Computer Science: As Introduction to Implicit Surfaces
Notation
Object-oriented Approach to Geometry Edited by Ju les B loomenthal
J im B linn
Leo Dorst, Daniel Fontijne, and Jim Blinn’s Corner: A Trip Down the
Stephen Mann Level of Detail for 3D Graphics Graphics Pipeline
David Luebke, Martin Reddy,
Point-Based Graphics J im B linn
Jonathan D. Cohen, Amitabh
M arkus G ross and H anspeter Varshney, Benjamin Watson, and Interactive Curves and Surfaces: A
P fister , Editors Robert Huebner Multimedia Tutorial on CAGD
High Dynamic Range Imaging: Data A lyn Rockwood and
Pyramid Algorithms: A Dynamic
Acquisition, Manipulation, and Display Peter Chambers
Programming Approach to Curves and
E rik Reinhard, Greg Ward, Sumanta Surfaces for Geometric Modeling Wavelets for Computer Graphics: Th eory
Pattanaik, and Paul Debevec Ron Goldman and Applications
Complete Maya Programming Volume II: E ric J. S tollnitz , T ony D. D eRose ,
Non-Photorealistic Computer Graphics:
An In-depth Guide to 3D Fundamentals, and D avid H. S alesin
Modeling, Rendering, and Animation
Geometry, and Modeling T homas Strothotte and Stefan Principles of Digital Image Synthesis
D avid A. D. G ould Schlechtweg Andrew S. Glassner
MEL Scripting for Maya Animators, Curves and Surfaces for CAGD: A Practical Radiosity & Global Illumination
Second Edition Guid e, Fifth Edition F rançois X. Sillion and Claude Puech
Mark R. Wilkins and Chris Kazmier
Gerald Farin Knotty: A B-Spline Visualization Program
Advanced Graphics Programming Using Subdivision Methods for Geometric Design: Jonathan Yen
OpenGL
A Constructive Approach User Interface Management Systems:
T om McReynolds and David Blythe
Joe Warren and Henrik Weimer Models and Algorithms
Digital Geometry Geometric Methods for Computer Animation: Algorithms and D an R. O lsen , Jr.
Digital Picture Analysis
Techniques Making Th em Move: Mechanics, Control,
R einhard Klette and Azriel
Rick Parent and Animation of Articulated Figures
Rosenfeld
Th e Computer Animator’s Technical Edited by N orman I. B adler , B rian
Digital Video and HDTV Algorithms and Handbook A. B arsky, and D avid Z eltzer
Interfaces
Lynn Pocock and Judson Rosebush Geometric and Solid Modeling: An
Charles Poynton
Advanced RenderMan: Creating CGI for Introduction
Real-Time Shader Programming Motion Pictures Christoph M. Hoffmann
R on F osner A nthony A. Apodaca and Larry Gritz
A n Introduction to Splines for Use in
C omplete Maya Programming: An Extensive Curves and Surfaces in Geometric Computer Graphics and Geometric Modeling
Guide to MEL and the C (cid:2) (cid:2) API Modeling: Th eory and Algorithms R ichard H. B artels , J ohn C. B eatty ,
D avid A. D. G ould J ean G allier and B rian A. B arsky
Learning
Processing
A Beginner’s Guide to
Programming Images,
Animation, and Interaction
Daniel Shiffman

AMSTERDAM • BOSTON • HEIDELBERG • LONDON
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08 09 10 11 12 5 4 3 2 1
Contents

Acknowledgments vii
Introduction ix
Lesson 1: The Beginning 1
Chapter 1: Pixels 3
Chapter 2: Processing 17
Chapter 3: Interaction 31
Lesson 2: Everything You Need to Know 43
Chapter 4: Variables 45
Chapter 5: Conditionals 59
Chapter 6: Loops 81
Lesson 3: Organization 99
Chapter 7: Functions 101
Chapter 8: Objects 121
Lesson 4: More of the Same 139
Chapter 9: Arrays 141
Lesson 5: Putting It All Together 163
Chapter 10: Algorithms 165
Chapter 11: Debugging 191
Chapter 12: Libraries 195
Lesson 6: The World Revolves Around You 1 99
Chapter 13: Mathematics 201
Chapter 14: Translation and Rotation (in 3D!) 227
Lesson 7: Pixels Under a Microscope 253
Chapter 15: Images 255
Chapter 16: Video 275
Lesson 8: The Outside World 303
Chapter 17: Text 305
Chapter 18: Data Input 325
Chapter 19: Data Streams 357
Lesson 9: Making Noise 379
Chapter 20: Sound 381
Chapter 21: Exporting 397
Lesson 10: Beyond Processing 407
Chapter 22: Advanced Object-Oriented Programming 409
Chapter 23: Java 423
Appendix: Common Errors 439
Index 447
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Acknowledgments
In the fall of 2001, I wandered into the Interactive Telecommunications Program in the Tisch School of
the Arts at New York University having not written a line of code since some early 80’s experiments in
(cid:2)
BASIC on an Apple II . Th ere, in a fi rst semester course entitled Introduction to Computational Media,
I discovered programming. Without the inspiration and support of ITP, my home since 2001, this book
would have never been written.
Red Burns, the department’s chair and founder, has supported and encouraged me in my work for the
last seven years. Dan O’Sullivan has been my teaching mentor and was the fi rst to suggest that I try a
course in Processing at ITP, giving me a reason to start putting together programming tutorials. Shawn
Van Every sat next to me in the offi ce throughout the majority of the writing of this book, providing
helpful suggestions, code, and a great deal of moral support along the way. Tom Igoe’s work with physical
computing provided inspiration for this book, and he was particularly helpful as a resource while putting
together examples on network and serial communication. And it was Clay Shirky who I can thank for
one day stopping me in the hall to tell me I should write a book in the fi rst place. Clay also provided a
great deal of feedback on early drafts.
All of my fellow computational media teachers at ITP have provided helpful suggestions and feedback
along the way: Danny Rozin (the inspiration behind Chapters 15 and 16), Amit Pitaru (who helped in
particular with the chapter on sound), Nancy Lewis, James Tu, Mark Napier, Chris Kairalla, and Luke
Dubois. ITP faculty members Marianne Petit, Nancy Hechinger, and Jean-Marc Gauthier have provided
inspiration and support throughout the writing of this book. Th e rest of the faculty and staff at ITP have
also made this possible: George Agudow, Edward Gordon, Midori Yasuda, Megan Demarest, Robert
Ryan, John Duane, Marlon Evans, and Tony Tseng.
Th e students of ITP, too numerous to mention, have been an amazing source of feedback throughout
this process, having used much of the material in this book in trial runs for various courses. I have stacks
of pages with notes scrawled along the margins as well as a vast archive of e-mails with corrections,
comments, and generous words of encouragement.

I am also indebted to the energetic and supportive community of Processing programmers and artists. I’d
probably be out of a job if it weren’t for Casey Reas and Benjamin Fry who created Processing . I’ve learned
half of what I know simply from reading through the P rocessing source code; the elegant simplicity of the
Processing language, web site, and IDE has made programming accessible and fun for all of my students.
I’ve received advice, suggestions, and comments from many P rocessing programmers including Tom
Carden, Marius Watz, Karsten Schmidt, Robert Hodgin, Ariel Malka, Burak Arikan, and Ira Greenberg.
Th e following teachers were also helpful test driving early versions of the book in their courses: Hector
Rodriguez, Keith Lam, Liubo Borissov, Rick Giles, Amit Pitaru, David Maccarella, Jeff Gray, and
Toshitaka Amaoka.
Peter Kirn and Douglas Edric Stanley provided extraordinarily detailed comments and feedback during
the technical review process and the book is a great deal better than it would have been without their
eff orts. Demetrie Tyler did a tremendous job working on the visual design of the cover and interior of this
viii Acknowledgments
book, making me look much cooler than I am. And a thanks to David Hindman, who worked on helping
me organize the screenshots and diagrams.
I’d also like to thank everyone at Morgan Kaufmann/Elsevier who worked on producing the book:
Gregory Chalson, Tiff any Gasbarrini, Jeff Freeland, Danielle Monroe, Matthew Cater, Michele Cronin,
Denise Penrose, and Mary James.
Finally, and most important, I’d like to thank my wife, Aliki Caloyeras, who graciously stayed awake
whenever I needed to talk through the content of this book (and even when I felt the need to practice
material for class) my parents, Doris and Bernard Shiff man; and my brother, Jonathan Shiff man, who all
helped edit some of the very fi rst pages of this book, even while on vacation.
Introduction
What is this book?
Th is book tells a story. It is a story of liberation, of taking the fi rst steps toward understanding the
foundations of computing, writing your own code, and creating your own media without the bonds of
existing software tools. Th is story is not reserved for computer scientists and engineers. Th is story is
for you.
Who is this book for?
Th is book is for the beginner. If you have never written a line of code in your life, you are in the right
place. No assumptions are made, and the fundamentals of programming are covered slowly, one by one,
in the fi rst nine chapters of this book. You do not need any background knowledge besides the basics of
operating a computer—turning it on, browsing the web, launching an application, that sort of thing.
Because this book uses P rocessing (more on P rocessing in a moment), it is especially good for someone
studying or working in a visual fi eld, such as graphic design, painting, sculpture, architecture, fi lm, video,
illustration, web design, and so on. If you are in one of these fi elds (at least one that involves using a
computer), you are probably well versed in a particular software package, possibly more than one, such as
Photoshop, Illustrator, AutoCAD, Maya, After Eff ects, and so on. Th e point of this book is to release you,
at least in part, from the confi nes of existing tools. What can you make, what can you design if, instead of
using someone else’s tools, you write your own? If this question interests you, you are in the right place.
If you have some programming experience, but are interested in learning about P rocessing , this book could
also be useful. Th e early chapters will provide you with a quick refresher (and solid foundation) for the
more advanced topics found in the second half of the book.
What is Processing ?

Let’s say you are taking Computer Science 101, perhaps taught with the Java programming language.
Here is the output of the fi rst example program demonstrated in class: