Processing: Creative Coding and Computational Art

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are filled with black. Using the intialNode variable allows the first plotted node’s color to be changed when the mouse is over it, providing some interactive direction to the user. // function returns true/false if mouse is over initial node boolean isInitialNode(){ boolean isOnNode = false; if (nodeXPos.length>2){ if (dist(mouseX, mouseY, nodeXPos[0], nodeYPos[0]) < nodeRadius){ isOnNode = true; } } return isOnNode; } The isInitialNode() function returns true if there are more than two nodes plotted and the mouse is over the initially plotted node. If neither of these conditions is true, the function returns false. Notice how I declared the function using the boolean keyword in front of the function name; this enforces that the function must return a Boolean value. Note also that the Boolean variable isOnNode, which I declared within the function, only exists locally (has local scope) within the function. void mousePressed(){ if(isShapeClosed){ // after shape is closed empty arrays nodeXPos = subset(nodeXPos, 0, 0); nodeYPos = subset(nodeYPos, 0, 0); xSpeed = subset(xSpeed, 0, 0); ySpeed = subset(ySpeed, 0, 0); jitter = subset(jitter, 0, 0); elasticity = subset(elasticity, 0, 0); //reset variable to false isShapeClosed = false; } if(!isInitialNode()){ // if not on initial node plot at mouse position // increase size of node coordinate arrays nodeXPos = append(nodeXPos, mouseX); nodeYPos = append(nodeYPos, mouseY); // increase size of dynamics arrays xSpeed = append(xSpeed, 0); jitter = append(jitter, random(-jitterRange, jitterRange)); elasticity = append(elasticity, random(elasticRangeMin, ➥ elasticRangeMax)); ySpeed = append(ySpeed, 0); } else { // set to true to avoid additional nodes on shape INTERACTIVITY 577 12
PROCESSING: CREATIVE CODING AND COMPUTATIONAL ART 578 isShapeClosed = true; } } The mousePressed() function begins with a conditional block that initializes the sketch arrays when the shape is closed; this allows new shapes to be plotted when the mouse is pressed (only after the shape has been closed and has begun animating). I used Processing’s subset() function to reset the primitive arrays. The function returns a subset of an array. The first argument is the array to subset, the second argument is the place in the array to begin the subset, and the third argument is the number of positions in the array to include in the subset. Since I used 0, 0 for the starting point and number of positions in the subset, an empty array was returned. Notice that I assigned the empty array back to the same array I used in the first argument; this may look odd, but it is perfectly legal. At the end of the conditional block, I reset the variable isShapeClosed to false to allow new nodes to be plotted. The next conditional block, if(!isInitialNode()), uses the ! operator with the function call isInitialNode(). The function call returns a Boolean value (true or false). Prefacing the function call with the exclamation mark means that the conditional test will evaluate to true when the function call returns false (i.e., when the user is not pressing on the initial node). This kind of logic can hurt your head. Instead of using !isInitialNode(), you could also use isInitialNode() == false or isInitialNode() != true to handle the test. Within the conditional block, I used Processing’s append() function. This function increases the length of arrays. The function takes two arguments: the first argument is the array to append to, and the second is the value to add to the array. Like subset(), the append() function returns the changed array, which I reassigned to the same array variable. On each mouse press, all six of the arrays are appended to. Finally, if the user clicks the initial node, the arrays are not expanded, but the Boolean variable isShapeClosed is set to true. void moveShape(){ //animate after shape is closed if (isShapeClosed){ for (int i=0; iwidth-nodeRadius){ nodeXPos[i] = width-nodeRadius; xSpeed[i]*=-1; } // left display window edge if (nodeXPos[i]
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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
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algorithms. To learn more about Coh
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landfill/), and Feed (www.potatolan
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periodicals such as Art Journal, Wi
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And many more . . . While I have in
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2 CREATIVE CODING
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I think what was reinforced for me
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customized commands, and run loops.
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of code that work like processing m
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introduced to become larger, more c
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Without getting too geeky, the main
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A framework is just a concept for b
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algorithm in a math class in high s
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frame. The loop keeps running and k
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the time to play at whatever level
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} pts[counter2].y-yg); xg*=-1; coun
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The overall movement was good, but
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Obviously, there are a lot of thing
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} } // generates organic looking br
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3 CODE GRAMMAR 101
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Your first program In most programm
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message comes up on the bar in the
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Since the getBreed() method would r
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Variables Variables are essential t
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It’s because strict typing helps
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Stage 3 adds the gradient: /* title
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Next, I assign values to some primi
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In the first preceding example, add
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Assignment operators The only other
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* title: Bouncing Ball description:
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Animation is a perfect example of t
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if (hunger= starving) { eatAnything
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Ternary operator The last condition
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The items array has 50 places reser
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println(x); x += 1; } while(x
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Figure 3-4. Continuous radial gradi
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int ballCount = 500; int ballSize =
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Hopefully, you were able to success
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function call above*/ // fill(i*255
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If you run this, you should see a 1
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yspeed*=-1; } } Within the draw() f
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void checkCollisions(int xp, int yp
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createRect(50, 50, 100, 100, 20, 5,
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4 COMPUTER GRAPHICS, THE FUN, EASY
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Some of the reasons coding graphics
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When working in a 3D coordinate sys
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plotted, the vertices are connected
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eally shines. And remember, as you
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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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Page 557 and 558: PROCESSING: CREATIVE CODING AND COM
Page 594 and 595: 12 INTERACTIVITY
Page 596 and 597: } public void mouseClicked(MouseEve
Page 598 and 599: void setup(){ size(400, 400); // in
Page 600 and 601: initialize x, y x = width/2.0; y =
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Page 606 and 607: As usual, I declare global variable
Page 610 and 611: } } } } } // bottom display window
Page 612 and 613: color btnUpState = color(200, 200,
Page 614 and 615: float xSpeed = 0; color movingSquar
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Page 618 and 619: mouse trails if (isTrailable){ fill
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Page 644: 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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