Book Image

Processing 2: Creative Programming Cookbook

Book Image

Processing 2: Creative Programming Cookbook

Overview of this book

Processing is probably the best known creative coding environment that helps you bridge the gap between programming and art. It enables designers, artists, architects, students and many others to explore graphics programming and computational art in an easy way, thus helping you boost your creativity. "Processing 2: Creative Programming Cookbook" will guide you to explore and experience the open source Processing language and environment, helping you discover advanced features and exciting possibilities with this programming environment like never before. You'll learn the basics of 2D and 3D graphics programming, and then quickly move up to advanced topics such as audio and video visualization, computer vision, and much more with this comprehensive guide. Since its birth in 2001, Processing has grown a lot. What started out as a project by Ben Fry and Casey Reas has now become a widely used graphics programming language. Processing 2 has a lot of new and exciting features. This cookbook will guide you to explore the completely new and cool graphics engine and video library. Using the recipes in this cookbook, you will be able to build interactive art for desktop computers, Internet, and even Android devices! You don't even have to use a keyboard or mouse to interact with the art you make. The book's next-gen technologies will teach you how to design interactions with a webcam or a microphone! Isn't that amazing? "Processing 2: Creative Programming Cookbook" will guide you to explore the Processing language and environment using practical and useful recipes.
Table of Contents (18 chapters)
Processing 2: Creative Programming Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Blob tracking


Now that you know how to apply a thresholding algorithm on a webcam feed, it's time to do some analysis on those pixels. We'll draw a rectangle around all white pixels in the image. This is a very basic brightness tracking algorithm and is useful when you want to create a simple interactive installation with a webcam.

How to do it...

We'll start by importing the video library and declaring some variables. We need a Capture object to access the webcam and an integer variable to use as a threshold value. The other integer variables are used to track the boundaries around the white pixels in the image.

import processing.video.*;
  
Capture webcam;
int threshold;
  
int topLeftX;
int topLeftY;
int bottomRightX;
int bottomRightY;
  
void setup()
{
  size( 640, 480 );

  webcam = new Capture( this, width, height, 30);
  webcam.start();
  
  threshold = 127;

  topLeftX = width;
  topLeftY = height;

  bottomRightX = 0;
  bottomRightY = 0;
}

Inside the draw() function, we'll apply the...