Learning Processing: A Beginner's Guide to Programming Images ...

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16 16.1 Video “ I have no memory. It’s like looking in a mirror and seeing nothing but mirror. ” —Alfred Hitchcock In this chapter: – Displaying live video. – Displaying recorded video. – Creating a software mirror. – How to use a video camera as a sensor. Before Processing Video 275 Now that we have explored static images in Processing , we are ready to move on to moving images, specifi cally from a live camera (and later, from a recorded movie). Using a digital video camera connected to a PC or Mac requires a few simple steps before any code can be written. On a Mac: • Attach a camera to your computer. • Make sure any necessary software and drivers for the camera are installed. • Test the camera in another program, such as iChat, to make sure it is working. On a PC: • Attach a camera to your computer. • Make sure any necessary software and drivers for the camera are installed. • Test the camera. (Use whatever software that came with your camera that allows you to view the video stream.) • Install QuickTime (version 7 or higher). If you are using a previous version of QuickTime, you must make sure you choose “ custom ” installation and select “ QuickTime for Java. ” • You will also need to install a vdig (video digitizer) that allows QuickTime applications (what we are creating) to capture video in Windows. The vdig situation is in flux so I recommend you check this book’s web site for updates. Although no longer being developed, a free vdig is available at this site: http://eden.net.nz/7/20071008/ . You can also consider using Abstract Plane’s vdig ( http://www.abstractplane.com.au/products/vdig.jsp ), which costs a small fee, but has more advanced features. Admittedly, the process is a bit less complicated on a Mac. Th is is because Processing uses the QuickTime libraries in Java to handle video. On Apple computers, QuickTime comes preinstalled (although sometimes software updates can cause issues), whereas on Windows, we have to make sure we have taken the steps to install and properly confi gure QuickTime. At the end of this chapter, we will see
276 Learning Processing that there are few third party libraries available in Processing that do not require QuickTime for video capture on Windows. 16.2 Exercise 16-1: Hook a camera up to your computer. Does it work in another program (not Processing)? If you are on a PC, install a vdig and test. Live Video 101 Once you have made sure you have a working camera connected to your machine, you can start writing Processing code to capture and display the image. We begin by walking through the basic steps of importing the video library and using the Capture class to display live video. Step 1. Import the Processing video library. If you skipped Chapter 12 on Processing libraries, you might want to go back and review the details. Th ere is not much to it here, however, since the video library comes with the Processing application. All you need to do is import the library. Th is is done by selecting the menu option Sketch → Import Library → video, or by typing the following line of code (which should go at the very top of your sketch): import processing.video.*; Using the “ Import Library ” menu option does nothing other than automatically insert that line into your code, so manual typing is entirely equivalent. Step 2. Declare a Capture object We learned in Chapter 12 how to create objects from classes built into the Processing language. For example, we made PImage objects from the Processing PImage class. PImage, it should be noted, is part of the processing.core library and, therefore, no import statement was required. Th e processing.video library has two useful classes inside of it—Capture, for live video, and Movie, for recorded video. We will start with declaring a Capture object. Capture video; Step 3. Initialize the Capture object. Th e Capture object “ video ” is just like any other object. As we learned in Chapter 8, to construct an object, we use the new operator followed by the constructor. With a Capture object, this code typically appears in setup( ) , assuming you want to start capturing video when the sketch begins. video = new Capture();
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Learning Processing A Beginner’s
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Learning Processing A Beginner’s
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Contents Acknowledgments vii Introd
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Acknowledgments In the fall of 2001
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Introduction What is this book? Th
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Introduction xi While both of these
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Introduction xiii Th e book is desi
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Introduction xv Th is book’s web
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Introductory Exercise: Write instru
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Lesson One The Beginning 1 Pixels 2
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1 Pixels “ A journey of a thousan
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1.2 Simple Shapes Pixels 5 Th e vas
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0 1 2 3 4 5 6 7 8 9 fi g. 1.9 top l
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1.3 Pixels 9 Exercise 1-3: Reverse
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Example 1-2: noFill ( ) background(
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fi g. 1.19 Pixels 13 Exercise 1-5:
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colorMode(RGB,100); Pixels 15 Th e
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2 2.1 Processing “ Computers in t
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fi g. 2.2 Once you have opened the
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Let’s write a fi rst example ( se
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Line 9 fi g. 2.6 Processing is case
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fi g. 2.7 Processing 25 Processing
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Example 2-1: Zoog again size(200,20
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Processing 29 To see the applet wor
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3 3.1 Interaction “ Always rememb
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Let’s look at what will surely be
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3.3 Variation with the Mouse Intera
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Draw Zoog's eyes fill(0); ellipse(8
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3.4 Mouse Clicks and Key Presses In
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Draw Zoog's eyes fill(mo useX,0,mou
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Lesson Two Everything You Need to K
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4 4.1 Variables “ All of the book
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4.2 Variable Declaration and Initia
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A variable can also be initialized
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x = 5; x = a + b; x = y - 10 * 20;
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void draw() { // Draw the backgroun
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4.6 Random: Variety is the spice of
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4.7 Example 4-7: Filling variables
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5 5.1 Conditionals Conditionals 59
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Finally, for testing multiple condi
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Conditionals 63 It is worth pointin
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Conditionals 65 Getting into the ha
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Our fi rst instinct might be to wri
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5.5 Multiple Rollovers Conditionals
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Conditionals 71 We can then check t
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5.7 Conditionals 73 Exercise 5-8: E
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Reversing the Polarity of a Number
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One way to solve this problem is to
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Display the square fill(0); noStrok
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6 Loops “ Repetition is the reali
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Loops 83 (see Chapter 5). However,
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while (y < 100) { // Loop! } 3. Wha
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while (x < = endLegs) { line(x,y,x,
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Th e same exact loop can be program
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Loops 91 Th is was a nice simplifi
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6.6 Loop Inside the Main Loop Loops
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6.7 float distance = abs(mouseX - i
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Draw Zoog's legs stroke(0); line(x-
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Lesson Three Organization 7 Functio
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7 7.1 Functions “ When it’s all
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7.2 “ User Defi ned ” Functions
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Example 5-6: Bouncing ball // Decla
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7.5 Functions 107 Exercise 7-3: Tak
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Functions 109 It should be fairly a
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int globalX = 0; int globalY = 100;
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void setup() { println( "a"); funct
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If we did not include a return stat
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7.8 Zoog Reorganization Zoog is now
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void draw() { } background(0); // D
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8 8.1 Objects “ No object is so b
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Setup: Draw: Initialize car color.
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Objects 125 • The Class Name—Th
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Objects 127 One other thing; with t
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fi g. 8.1 fi g. 8.2 fi g. 8.4 fi g.
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Objects 131 Nevertheless, this is q
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void draw() { } background(100); ba
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Objects 135 modular, reusable packa
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Lesson Three Project Step 1. Take y
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Lesson Four More of the Same 9 Arra
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9 Arrays “ I might repeat to myse
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Car myCar80 Car myCar81 Car myCar82
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9.3 Declaring and Creating an Array
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9.4 Initializing an Array One way t
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Example 9-5: Using a for loop to in
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Arrays 151 Now comes the hard part.
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9.7 Arrays 153 Exercise 9-7: Rewrit
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9.8 Interactive Objects Arrays 155
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Check if point is inside of Stripe
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alls[i].gravity(); balls[i].move();
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Draw Zoog's arms with a for loop fo
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Lesson Five Putting It All Together
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10 10.1 Algorithms “ Lather. Rins
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Translating the preceding algorithm
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void draw() { background(255); stro
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Example 10-2: Bouncing ball class c
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Now that the function is complete,
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10.6 // Constructor Ball(float temp
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Algorithms 177 With the above logic
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Drop() { r = 8; // All raindrops ar
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Example 10-7: Drops one at a time /
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Algorithms 183 Notice how every sin
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oolean intersecting = ball1.interse
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} void setLocation(float tempX, flo
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Algorithms 189 It is important to r
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11 Debugging “ Th e diff erence b
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Debugging 193 Once all the code is
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12 Libraries “ If truth is beauty
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or /Applications/Processing 0135/ c
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Lesson Six The World Revolves Aroun
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13 Mathematics Mathematics 201 “
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Mathematics 203 Th erefore, modulo
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Th e probability of a coin fl ippin
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13.6 Perlin Noise Mathematics 207 O
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Mathematics 209 How quickly we incr
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It is fairly intuitive for us to th
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fi g. 13.9 y-axis sine(theta) � y
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Example 13-6: Oscillation float the
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Mathematics 217 In 1975, Benoit Man
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Mathematics 219 said about recursio
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Mathematics 221 A two-dimensional a
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Example 13-10: Two-dimensional arra
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Page 246 and 247: 14 14.1 Translation and Rotation (i
Page 248 and 249: Our fi rst instinct might be to add
Page 250 and 251: Example 14-3: A rectangle moving al
Page 252 and 253: When using the OPENGL mode, you mus
Page 254 and 255: Translation and Rotation (in 3D!) 2
Page 256 and 257: 14.5 fill(150,150); vertex(-t, t,-t
Page 258 and 259: 14.6 Example 14-5: Rectangle rotati
Page 266 and 267: fill(0,100); // Note the use of pus
Page 268 and 269: 14.9 Example 14-17: Nested push and
Page 270 and 271: stroke(0); fill(175); ellipse(0,0,d
Page 272 and 273: Lesson Seven Pixels Under a Microsc
Page 274 and 275: 15 Images Images 255 “ Politics w
Page 276 and 277: And yet: PImage img = loadImage( "f
Page 278 and 279: 15.3 My Very First Image Processing
Page 280 and 281: Images 261 Even better, if we just
Page 282 and 283: Images 263 // Create a grayscale co
Page 284 and 285: Images 265 15.6 Intro to Image Proc
Page 286 and 287: Images 267 Since we are altering th
Page 288 and 289: 15.9 More on fi lter( ): fi lter(mo
Page 290 and 291: Images 271 Example 15-13 performs a
Page 292 and 293: Example 15-14: “ Pointillism ”
Page 296 and 297: Video 277 Th e above line of code i
Page 298 and 299: void draw() { // Check to see if a
Page 300 and 301: 16.3 Recorded Video Video 281 Displ
Page 302 and 303: 16.4 Video 283 Exercise 16-3: Using
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Page 306 and 307: } } // Each rect is colored white w
Page 308 and 309: 16.5 Video as Sensor, Computer Visi
Page 310 and 311: Now, we are ready to compare the co
Page 312 and 313: 16.6 Video 293 Exercise 16-5: Take
Page 314 and 315: void setup() { size(320,240); video
Page 316 and 317: Example 16-13: Simple motion detect
Page 318 and 319: 16.8 // Step 4, compare colors (pre
Page 320 and 321: Lesson Seven Project Develop a soft
Page 322 and 323: Lesson Eight The Outside World 17 T
Page 324 and 325: 17 17.1 Text “ I could entertain
Page 326 and 327: Exercise 17-2: Loop through and pri
Page 328 and 329: 17.3 Displaying Text Text 309 We wi
Page 330 and 331: println(PFont.list()); For demonstr
Page 332 and 333: X = �50 fi g. 17.4 float w = text
Page 334 and 335: Example 17-4: Text mirror import pr
Page 336 and 337: textFont(f); // Set the font transl
Page 338 and 339: Exercise 17-9: Using textWidth( ) ,
Page 340 and 341: Example 17-7: Boxes along a curve P
Page 342 and 343: Text 323 Exercise 17-10: Create a s
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18 Data Input “ A million monkeys
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Example 18-1: User input PFont f; /
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Data Input 329 Th e reverse of spli
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Example 18-2: Graphing comma separa
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Data Input 333 Th e rollover( ) fun
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18.4 diameter = diameter_; } // Tru
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} // Find the index of the end tag
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void mousePressed() { // Increment
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18.6 for (int i = 0; i < kinglear.l
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Create and make an asynchronous req
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� student � � id � 002 �
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Requests for XML data are made via
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18.8 Using the Processing XML Libra
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XMLElement diameterElement = childr
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Example 18-10: A Yahoo search impor
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However, if you request a URL on a
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19 19.1 Data Streams “ I’m mad
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import processing.net.* ; Server se
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Data Streams 361 Once the server is
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19.4 void draw() { background(255);
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Data Streams 365 must be networked
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Data Streams 367 will send X , Y co
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Data Streams 369 Here is the full S
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Here is the entire client sketch: 1
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Data Streams 373 Serial communicati
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Data Streams 375 of information, ca
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Corresponding Arduino code: int sen
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Lesson Nine Making Noise 20 Sound 2
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20 Sound “ Check. Check. Check 1.
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void setup() { Sonia.start(this); }
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void mousePressed() { // If the use
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Sound 387 check and see if a sound
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Is a point inside the doorbell (use
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Pressing the mouse stops and starts
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20.6 void draw() { background(255,1
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In code, this translates to: // If
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21 Exporting “ Wait a minute. I t
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Th is code can be inserted anywhere
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void setup() { size(400, 400); begi
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Exporting 403 save( ) takes one arg
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Exporting 405 Example 21-5 records
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Lesson Ten Beyond Processing 22 Adv
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22 Advanced Object-Oriented Program
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class Point { float x,y; Point(floa
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Advanced Object-Oriented Programmin
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Advanced Object-Oriented Programmin
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class Circle extends Shape { // inh
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for (int i = 0; i < dogs.length; i
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22.5 Example 22-2: Polymorphism //
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23 23.1 Java “ I l o ve c off ee,
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Java 425 instead of Processing , sp
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fi g. 23.2 Java 427 Just as with th
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Particle p = parray[i]; p.run(); p.
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Hint: Add a function that returns a
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Example 23-4: Super fancy ArrayList
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Java 435 It is sad when these error
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Th e tutorials will cover the same
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Appendix: Common Errors Appendix 43
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Error: No accessible fi eld named
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void draw() { thing.display(); } Co
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Error: Perhaps you wanted the overl
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Index AIFF (Audio Interchange File
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Fill( ) function 10 , 11 , 256 , 30
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One-dimensional Perlin noise 208 OP
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solar system, processing 247-9 vert
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