Processing: Creative Coding and Computational Art

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It’s because strict typing helps create more precise and ultimately faster-running code. If you try to assign a float value—for example, 3.2—to int ballCount, Processing will spit back a compiler error that says The type of the right sub-expression, "float", is not assignable to the variable, of type "int". This may seem obnoxious and a royal pain, especially if you are used to a loosely typed language, but it really is a useful (or at least justifiable) language feature. Save for the strange worlds of quantum physics, we would expect distinct whole balls to be held in ballCount—not parts of balls. If the compiler let you assign 3.2 (maybe entered due to a typo) to ballCount, your program would probably crash later on. To debug your program, you would then have to track down a tiny but fatal type conversion error (definitely not a happy coding accident). Additionally, in languages that do permit on-the-fly data type assignment, it takes more work for the computer to figure out what type of data is held in a variable. Because you set the data type of variables when they are declared in Processing and Java, and that information gets put in the compiled bytecode, the virtual machine (the language interpreter) needs to do less work. Languages like Processing and Java that work this way are called statically typed languages. Languages like Python, on the other hand, are dynamically typed, and, due in part to dynamic typing, run slower than Java and Processing. Now, at the risk of really getting you rankled, what do you think would happen if you tried to assign 3 (an integer) to ballSpeed (declared as type float)? Surprisingly, you wouldn’t get a compiler error. Huh! That seems to go against what I just wrote about how static typing works. The reason the compiler allows it is because the compiler converts the 3 to 3.0 automatically. Let’s test this out. If I try running the following code: float ballSpeed; ballSpeed = 3; println(ballSpeed); I get the following output: 3.0 The reason the compiler lets me get away with this is because there is no danger, nor any real change, to the value. 3, 3.0, and even 3.0000000000000 are all equal. Not to get too geeky, but this type of implicit conversion is called a “widening conversion,” where an int is automatically converted into a float. The rule is that any primitive type will be converted implicitly (without any help from you) into any other type only if that type supports a larger value; a float supports a larger value than an int. In regard to Processing, that would include byte to int and int to float. Bytes can become integers and integers can become floats. Converting the other way, from a float to an int to a byte (a “narrowing conversion”) can actually also happen, but you have to do it explicitly (which involves a little work on your part), with something called type casting, which I’ll cover later in the book. For now, let’s put this theory stuff to bed and play with variables a little. Here’s a little program to create a stepped radial gradient (see Figure 3-2). Later on when I cover loops, I’ll simplify this program, and also show you how to generate a more elegant continuous gradient. You’ll create the program in three stages. The first stage will fill the CODE GRAMMAR 101 67 3
PROCESSING: CREATIVE CODING AND COMPUTATIONAL ART 68 display window background with black. The second stage will add a white ellipse, and the third stage will create the gradient. In stages 2 and 3, you just need to add the new code shown in bold. Also, try running the sketch at each stage to see the effect of adding the new code. Stage 1 just generates a black 200-by-200-pixel display window: /* title: fun with variables description: stepped radial gradient created: August 7, 2005 by: Ira Greenberg */ // set the sketch window size and background size(200,200); background(0); Stage 2 utilizes some variables and draws a white ellipse in the middle of the display window: /* title: fun with variables description: stepped radial gradient created: August 7, 2005 by: Ira Greenberg */ // declare some global variables int xpos; int ypos; int gradientWidth, gradientHeight; // set the sketch window size and background size(200,200); background(0); // radial width/height gradientWidth = gradientHeight = width; //radial center pt xpos = width/2; ypos = height/2; //turn off stroke rendering noStroke(); //create ellipses ellipse(xpos, ypos, gradientWidth, gradientHeight);
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IrA GreenberG CreATe CoDe ArT, vIsu
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Processing: Creative Coding and Com
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CONTENTS AT A GLANCE Foreword . . .
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CONTENTS Foreword . . . . . . . . .
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CONTENTS viii The joy of math . . .
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CONTENTS x Applying OOP to shape cr
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CONTENTS xii Environment . . . . .
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FOREWORD If you are like me (and th
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ABOUT THE AUTHOR With an eclectic b
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ACKNOWLEDGMENTS I am very fortunate
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INTRODUCTION Welcome to Processing:
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INTRODUCTION xxii Intended audience
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INTRODUCTION xxiv Setting up Proces
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INTRODUCTION xxvi Hopefully by now
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INTRODUCTION xxviii Figure 3. Scree
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INTRODUCTION xxx New or changed cod
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1 CODE ART
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The problem with a Photoshop filter
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Figure 1-3. Example of ancient art
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then jump 400 years to 1614 and Joh
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fertile imagination remained intact
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As an aside, it’s worth observing
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John Whitney Sr., 1918-1995 John Wh
Page 48 and 49: algorithms. To learn more about Coh
Page 50 and 51: landfill/), and Feed (www.potatolan
Page 52 and 53: periodicals such as Art Journal, Wi
Page 54 and 55: And many more . . . While I have in
Page 58 and 59: 2 CREATIVE CODING
Page 60 and 61: I think what was reinforced for me
Page 62 and 63: customized commands, and run loops.
Page 64 and 65: of code that work like processing m
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Page 68 and 69: Without getting too geeky, the main
Page 70 and 71: A framework is just a concept for b
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Page 74 and 75: frame. The loop keeps running and k
Page 76 and 77: the time to play at whatever level
Page 78 and 79: } pts[counter2].y-yg); xg*=-1; coun
Page 80 and 81: The overall movement was good, but
Page 82 and 83: Obviously, there are a lot of thing
Page 84 and 85: } } // generates organic looking br
Page 88 and 89: 3 CODE GRAMMAR 101
Page 90 and 91: Your first program In most programm
Page 92 and 93: message comes up on the bar in the
Page 94 and 95: Since the getBreed() method would r
Page 96 and 97: Variables Variables are essential t
Page 100 and 101: Stage 3 adds the gradient: /* title
Page 102 and 103: Next, I assign values to some primi
Page 104 and 105: In the first preceding example, add
Page 106 and 107: Assignment operators The only other
Page 108 and 109: * title: Bouncing Ball description:
Page 110 and 111: Animation is a perfect example of t
Page 112 and 113: if (hunger= starving) { eatAnything
Page 114 and 115: Ternary operator The last condition
Page 116 and 117: The items array has 50 places reser
Page 118 and 119: println(x); x += 1; } while(x
Page 120 and 121: Figure 3-4. Continuous radial gradi
Page 122 and 123: int ballCount = 500; int ballSize =
Page 124 and 125: Hopefully, you were able to success
Page 126 and 127: function call above*/ // fill(i*255
Page 128 and 129: If you run this, you should see a 1
Page 130 and 131: yspeed*=-1; } } Within the draw() f
Page 132 and 133: void checkCollisions(int xp, int yp
Page 134 and 135: createRect(50, 50, 100, 100, 20, 5,
Page 138 and 139: 4 COMPUTER GRAPHICS, THE FUN, EASY
Page 140 and 141: Some of the reasons coding graphics
Page 142 and 143: When working in a 3D coordinate sys
Page 144 and 145: plotted, the vertices are connected
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need to be stored in memory, and th
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Within each of these application ar
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don’t realize you’re doing it
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Geometry Like algebra, geometry dat
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(second-degree) curve has one turni
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or possibly even a complete crash o
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This linear motion would plot as a
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and began doubling. By step 80, the
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*Simple Repeating Wave Pattern Ira
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float waveGap = 10; float frequency
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a piece of paper and do a little mo
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Interactivity Figure 4-13. Puff Peo
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Events will be covered and implemen
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PROCESSING: CREATIVE CODING AND COM
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6 LINES
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Figure 6-2. Two-point sketch Adding
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Streamlining the sketch with a whil
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type into the sketch. Although the
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Figure 6-7. Randomized particle spr
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Figure 6-9. Multiple randomized par
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Coding a grid To begin, I’ll show
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Notice that you can make the value
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float steps = totalPts+1; int total
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Creating space through fades Your l
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for (int j=0; j
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Figure 6-19. Yin Yang Fade sketch,
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coordinates of the line. For exampl
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Figure 6-24. End cap variation exam
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Figure 6-25. Auto Layout sketch Thi
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int xPadding = 150; int yPadding =
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Figure 6-27. Table Layout II sketch
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for (int i=0; i
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This is the same drawTable() functi
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easy. The benefit of internally rec
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I call my custom function makeRect(
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As you might suspect, anti-aliasing
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call scribble function strokeWeight
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else { } // extra line needed to at
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smooth(); float x = random(width);
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Figure 6-36. Concentric Maze sketch
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void setup(){ //these values can be
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Create a Triangle size(400, 400); b
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Figure 6-39. Create 3 Triangles ske
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Poly Pattern I (table structure) /*
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Poly Pattern II (spiral) /* Poly Pa
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Poly Pattern III (polystar) /* Poly
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Figure 6-46. Poly Pattern III (poly
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7 CURVES
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size(200, 200); background(255); in
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You should notice some familiar str
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int margin = height/15; strokeWeigh
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Figure 7-8. Revealing the points ma
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* Curves II Ira Greenberg, December
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lower particle speed ySpeed[i]*=gra
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Figure 7-11. Curves simulating a fo
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Figure 7-13. Damping effect on curv
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particle style strokeWeight(strokeS
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By using functions to organize a pr
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for (int i=0; i
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Figure 7-18. Generating a curve wit
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float x = 0, y = 0; int loopLimit =
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concentric circles size(200, 200);
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Pie charts, although valuable as vi
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curve() and bezier() The next two P
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Next is an interactive example that
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Figure 7-27. Interpolating a Bézie
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ezier(350, 100, 400, 150, 350, 250,
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Figure 7-30. Spline curve using Pro
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curve segments noFill(); // comment
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control handles fill(255); ellipse(
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Figure 7-32. bezier() vs. bezierVer
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curveVertex(92+x, 15); curveVertex(
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strokeWeight(.75); stroke(0); rectM
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Figure 7-35. Bézier Ellipse sketch
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I included one last example (shown
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curveTightness(tightness); beginSha
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Summary Curves, and the math behind
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10 COLOR AND IMAGING
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left squares fill(255, 120, 0); rec
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the color. Up to this point in the
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} radius*=ratio; ratio-=.1; } } els
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Figure 10-4. Alpha sketch In this e
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A quick review of creating transfor
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* Nematode - stage 1 Ira Greenberg,
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Figure 10-8. Nematode sketch (stage
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Figure 10-9. Finished Nematode sket
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the decreasing wavelengths of the i
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values, just to illustrate the poss
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lerpColor() uses the same approach
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I want to mention two final points
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column for (int i=x; i
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needs to be increased, as radius in
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Figure 10-19. Wave Gradient sketch
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for (int i=0; i
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Figure 10-23. Load an Image sketch
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The image() function has an extra f
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In the last example, I created an a
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Figure 10-27. Simple Image Encrypti
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Figure 10-28. Pixilate sketch The n
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Figure 10-30. Tint sketch Speeding
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* Tint (using bitwise operations) C
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the book that a primitive type is d
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The mask works like an alpha channe
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ect(random(width), random(height),
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This last sketch couldn’t be simp
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separate out and invert component c
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Figure 10-39. GRAY Filter sketch Th
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adius is set high, the blurring can
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lend() PImage Method sketch // both
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Figure 10-45. blend() Function with
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The next sketch utilizes some for l
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In the last example, I used Process
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Inheritance In OOP, inheritance des
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AXIS_VERTICAL from outside the Grad
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y axis if(axis == AXIS_VERTICAL){ f
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calculate differences between color
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c7 = color(0); c8 = color(255); r1
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In the “Imaging” section, you d
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12 INTERACTIVITY
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} public void mouseClicked(MouseEve
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void setup(){ size(400, 400); // in
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initialize x, y x = width/2.0; y =
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float friction = .85; float[]jitter
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nodeYPos = append(nodeYPos, mouseY)
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As usual, I declare global variable
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are filled with black. Using the in
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} } } } } // bottom display window
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color btnUpState = color(200, 200,
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float xSpeed = 0; color movingSquar
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xSpeed-=.2; btn1Background = btnDow
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mouse trails if (isTrailable){ fill
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isTrailsSelected, which changes the
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shapes. The following example, in s
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set initial button background color
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also makes the code a little harder
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stroke(200); rect(eraserBtn[0], era
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} sliderValue = (sliderHandle[0]-sl
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if (!isBrushSelected){ if (mouseX>b
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selection can be active at a time.
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ectBackground = color(255, 0, 0); }
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is smaller (vertically) than the en
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keys 2-8 control number of edges fo
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strokeWeight(strokeWt); float angle
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Summary We began this chapter compa
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A PROCESSING LANGUAGE API
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http://processing.org/. My main obj
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its binary equivalent. I used some
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part of the article as well. My sug
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Example 1: A Java approach void set
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The combination of these two struct
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Example 3: Creating a honeycomb gra
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Conditionals Conditionals and the r
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Shape // top and bottom boundaries
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You’ll notice that by default, th
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start dragging if flag true for (in
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pushMatrix(); rotateY(-frameCount*P
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egular polygon size(400, 400); smoo
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texture(images[3]); vertex(w, -h/2,
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lots of arrays float[]x = new float
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Keyboard Figure A-9. Box Springs sk
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entering CMD). When using a command
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hour hand strokeWeight(2); stroke(5
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In the next example, I use beginRec
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Transformations include moving, sca
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float ang; int rows = 20; int cols
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vertex(-w/2 + shiftX, -h/2 + shiftY
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Lights The Lights section includes
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system, you can try lowering the re
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ankAngle+=bankSpeed; vert = -600 +z
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Setting The Setting section include
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ellipseMode(CORNER); fill(200, 200,
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of this part of the API. These myst
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Image The Image section relates ver
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Loading & Displaying The Loading &
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these elements is the creation of a
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Typography Processing utilizes mult
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This will output a list of all the
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“Operators” will hopefully soun
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The noise() function is an advanced
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B MATH REFERENCE
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After multiplying, you can reduce t
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Here’s an example: When dividing,
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Figure B-1. Using a right triangle
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Here’s how the process works: pic
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In Figure B-5, the point p is at 45
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ect (px, py, 5, 5); stroke(100); li
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manipulation is one area in which b
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the number, as shown in the followi
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Here’s the output: c1 in binary =
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This sketch outputs the following:
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I’m not going to provide examples
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simple-looking paint bucket tool in
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Figure B-7. Color variations filter
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INDEX 776 SYMBOLS AND NUMERICS /* a
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INDEX 778 beginShape function, 209
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INDEX 780 clipping planes, frustum,
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INDEX 782 naming conventions/rules,
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INDEX 784 functions, 440 loadPixels
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INDEX 786 filter function, 452-459
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INDEX 788 minute, 708 modelX/modelY
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INDEX 790 H haptics, 108 has-a rela
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INDEX 792 MouseListener interface,
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INDEX 794 M Mac keyboard shortcuts,
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INDEX 796 classes, 304, 321 constan
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INDEX 798 coding in 3D, 616 mapping
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INDEX 800 procedures see functions
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INDEX 802 Hybrid Shape, 366, 368 Hy
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INDEX 804 radians, converting betwe
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INDEX 806 Nematode sketch, 411, 413
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INDEX 808 text Orbiting Text sketch
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INDEX 810 VERY_HIGH option, encrypt
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