Should I include:

for (Ball b: balls) {
  b.display();
}

in addition to

for (int i = 0; i < balls.length; i++) {
  balls[i].display();
}

Perhaps I'll wait for Chapter 23 and ArrayLists to mention the enhanced loop? Or should I redo all examples and use it throughout?

Check for consistency:

• two space indentation

Also:

• arguments separated by commas with no spaces or one space after comma?
• spaces between operators or no?

line(x + y, 100, 50, 100);
line(x+y,100,50,100);

Decisions, decisions. . .

"Duck Hunt, where a bullet is shot whenever the user claps."

would prefer something less violent.

"IntList is faster than ArrayList (since ArrayList uses Integer objects) and less fussy than typing/explaining ArrayList. It also lets you sort things directly (ascending/descending) instead of needing some odd Collections thing… Basically any time you'd want to use ArrayList, you're better off w/ IntList. As compared to int[], it's less housekeeping since you're not keeping track of the length of the array and that sort of thing."

"p. 159 You might want to explain the immensely important line “y=height” which keeps the ball from jiggling on the line by resetting it to be exactly at the line itself. This turns out to be a big problem in this kind of algorithm"

Maybe just a quick paragraph at the end of the vertex-shapes section

http://processing.org/tutorials/pshape/

mention? Array chapter?

This code does not correct for stepping over the boundaries.

When the code reaches the first boundary (c1 == 255.1, c2 == -0.1), both c1dir and c2dir are negated, but c1 and c2 retain the values 255.1 and -0.1 which will be passed to fill() on the next call to draw(). Similarly for each colour variable heading in the other direction.

Including "c1 = c1 + c1dir;" in the first conditional will repeat the boundary value, so a nice crisp bounce is produced with "c1 = c1 + 2 * c1dir;" or equivalent code.

I might also suggest using variable names other than c1dir and c2dir since they are rates of change, not merely (or perhaps not even) "directions".

A similar problem exists in the "bouncing ball" (Example 5-6) code, but is arguably less "critical" (the ball doesn't "bounce" until the centre passes the edge anyway). The bouncing ball problem is one that I still find tricky - for example, a bouncing ball under "gravity" that eventually comes to rest, and that looks good, is not so easy!

from a reader: "I don't know if, when you introduce the draw function, there was anything about bugs that can show up from changing stroke settings toward the end of repeated code. It took me a while to troubleshoot a student using noStroke near the end of a figure that, when he put it into draw, changed dramatically. Maybe a warning that the default drawing settings are not restored when the loop resets."

While everyhing needs to be checked, these chapters have a ton of changes and need to be examined closely.

• chapter 18 - data
• chapter 20 - sound

The book I'm referring to is "Learning Processing" A Beginner's Guide to Programming Images, Animation, and Interaction. In lesson 2, chapter 6, example 6.3 the code is correct but the illustration is not. It looks like it illustrates:
size(200,200);
background(255);
int y = 60;
int x = 50;
int spacing = 10;
int len = 20;
int endLegs = 150;
stroke(0);
while (x <= endLegs) {
line (x,y,x, y + len);
x = x + spacing;
}

rather than

size(200,200);
background(255);
int y = 80;
int x = 50;
int spacing = 10;
int len = 20;
int endLegs = 150;
stroke(0);
while (x <= endLegs) {
line (x,y,x, y + len);
x = x + spacing;
}

In other words, int y = 80 should be int y = 60 to match the illustration (fig 6.3).

Holding off on Chapter 12 now as the explanation will need to be updated according to how the contribution manager ends up.

need to revisit this later in the summer when 3.0 IDE work is completed or closer to completion.

I need to finalize the actual sound files used for the examples. I need:

• a song (for playback, manipulation, effects, etc.)
• a doorbell sound effect (could change to something else)
• a drumbeat(?) for sound when ball hits edge of screen

Thanks to @therewasaguy, I'll investigate http://freemusicarchive.org/, http://www.freesound.org/, and http://ccmixter.org/

Despite the time spent on the client / server is indeed asynchronous (a short simple request may invoke a long server-side response), the use of asynchronous request is incorrectly used in 18.6 and 19.1. You also address blocking, which really means "synchronous," so this is important to keep aligned.

18.6
_a request ... is asynchronous, meaning ...
This should be is synchronous, meaning your program waits for a response from the server before continuing.

19.1
The above process is known as an asynchronous request and response
This should be The above process is known as a synchronous request and response, because the client waits until the server responds before sending another message.

imagine if you were to use asynchronous...
This should be imagine if you were to use synchronous...

...a different type of connection is used, a synchronous one...
This should be ...a different type of connection is used, an asynchronous one...

Synchronous communication is also necessary for live...
This should be Asynchronous communication is also necessary for live...

fig. 19.1 Left diagram should be Synchronous request.

I think you can essentially swap your use of synchronous/asynchronous without causing the need for any additional elaboration.

need new ones

• code from setup/draw to object needs to be fixed as so: http://www.processing.org/tutorials/objects/imgs/class.jpg
• all screenshots should be updated
• new diagram for pass by value with objects

I have a reacheBottom() method but it's never used (although it's referred to in the exercise at the end of the chapter)

  // Check if it hits the bottom
  boolean reachedBottom() { <span class="callout-bubble">In addition, we have a function that determines if the drop leaves the window.</span>
    // If we go a little past the bottom
    if (y &gt; height + r*4) {
      return true;
    } else {
      return false;
    }
  }

Take out or explain?

There is a mismatch between code and description on page 93.

The code says "background(255);" and the text below reads "Draw a black background" where it should read "Draw a white background".

In between noise and trig

• exercise will be to use map() for noise
• then use it in trig examples
• also use map() in final 2d array of cell objects example

Tracking my first pass over chapters. Specific chapter related issues will be filed separately.

• acknowledgments
• intro
• chp 1 pixels
• chp 2 Processing
• chp 3 interaction
• chp 4 variables
• chp 5 conditionals
• chp 6 loops
• chp 7 functions
• chp 8 objects
• chp 9 arrays
• chp 10 algorithms
• chp 11 debugging
• chp 12 libraries
• chp 13 mathematics
• chp 14 3D (PShape, PShader mentions?)
• chp 15 images
• chp 16 video (GStreamer, not quicktime)
• chp 17 text
• chp 18 data (Table, XML, JSON?)
• chp 19 data streams
• chp 20 sound (new library!)
• chp 21 exporting (no more applets, JS discussion)
• chp 22 advanced OOP
• chp 23 Java (generics?)
• appendix

Using the new processing.sound core library by @wirsing. My tentative plan is:

• basic sound file playback (music, sound effect)
• playback manipulation (amplitude, rate, pan)
• simple sound synthesis (a wave?)
• audio input, volume tied to ellipse size
• audio input, thresholding (trigger event on clap)
• audio input, spectrum???

I read Chapter 1 the Learning Processing book, and I think there
may be additional errata for Section 1.1, page 4, on Fig 1.2:

You say to think of the "verb" as a "function" and the "arguments" as
"objects" and in the figure you have bubbles labeled "object"
pointing at the arguments and a bubble labeled "verb" pointing at the
verb. Is that bubble meant to be labeled "function"?

img.loadPixels(); is there, but it is on the wrong line (same line as the comment) and thus not executed. Same thing for 15.8 btw.

There are some problems (inaccuracies) with the way pass-by-value and pass-by-reference are presented in the text. First, I recognize that this is a topic that is "more advanced" than the student should be, so I understand the approach of simplifying the concepts.

7.6
but will not be the case when we learn about objects in the next chapter.
This is incorrect because chapter 8 is incorrect. Objects, and all things in Java, are pass by value. The fact that an object variable is a reference to an object does not change the fact that a copy of the reference is passed to functions. I would simplify this last phrase as but is not quite the same with objects, which we will learn about in the next chapter.

8.7
With objects, this is not the case, and the result is a bit more intuitive. If changes are made to an object after it is passed into a function, those changes will affect that object used anywhere else throughout the sketch. This is known as pass by reference since instead of a copy, a reference to the actual object itself is passed into the function.
This paragraph is wrong, but I feel like there are only two solutions: either simplify this in the main copy as just With objects, this is not the case: if changes are made to an object after it is passed into a function, those changes will affect that object used anywhere else throughout the sketch and provide details about object variables being references in the sidebar; or delve into how objects are represented in memory and so on. One of the best illustrations for this concept is in the Head First Java book. However, in keeping with the spirit of your book, I would simplify this concept, removing the incorrect statement, and perhaps address the "why" in a gray sidebar box like you did in a few other places.

Need to double check the in this chapter lists at the start of each chapter, in particular for the ones that have changed majorly

• Video
• Data
• Sound
• Exporting

and all others

Reference these in chapter 18 / data?

quick intro then reference nature of code

Ch20 Sound Example 20-2. caption reads Doorbell with Sonia :-)

Suggested Label: book content

I don't think I would cover it earlier but perhaps alluding / hinting to images would be helpful.

"The book has extensive about image manipulation. However I miss images in the first chapters. I found that students like to draw the Zoog, but they are also curious to work with real images. Maybe parts of the Zoog can be a transparant PNG and an SVG. In this way students exercise with images as well. However this could also introduce to many new concepts in the first chapters."

I might as well include color screenshots for digital versions of book.

• images/01fig18.jpg
  [ ]

Need to rewrite

Processing 3.0 will have new, friendlier error messages. Need to make sure I am using the right language.

https://github.com/shiffman/Learning-Processing-2.0/blob/master/ch06.html#L509

For example, chapter 6: “No accessible field named “variableName” was found”

Hi, Shiffman

Details i have send to you by e-mail,[email protected].
if you receive my e-mail, could you reply me? Thanks very much!

Best,
Fengquan

needs a major update using current technologies and 2.0 API

not sure about this one:

On page 91, Example 6-7, the code in the first box should (only) be:

void setup() {
size(200,200);
}

IOW, the code:

void draw() {
background(0);

should be moved out of the first box and placed at the top of the second box.

need instructions for installing the video library

I think you have it backwards on page 109. (See
http://stackoverflow.com/questions/427653/arguments-or-parameters and
http://en.wikipedia.org/wiki/Parameter_%28computer_programming%29)

I find it easier to teach as: Parameters are Placeholders (both begin
with "P"), and Arguments are the Actual values that fill them in (both
begin with "A")

Need a better naming convention --

LP_1_10_Description.pde

or something

need new ones, in particular data.txt should be data.csv.

I stumbled a little with the section on PImage. In a future edition, I would suggest adding that the filename extensions, ".jpg", ".png" etc. are required. When I tried without them, I got a bunch of error messages and it took me awhile to realize that without the extensions, it doesn't work. I skimmed back over the chapter and didn't read mention of this (perhaps I missed it).

In the example on using a for loop to load images into an array, top of p. 261, I wondered about the sample filenames there "animal1.jpg", "animal2,jpg". Since in the for loop the first time through, i = 0, if there is no "animal0.jpg" won't you get an error?

At the end of chapter 11 mention something about the new 3.0 debugger, possibly with a screenshot.

Teaching at ITP, I've found that continuing to play with an elaborate design throughout the first half of the book doesn't necessarily work well and I usually have students start over with something simpler after creating their "Zoog." But maybe in the book, this works well and I should keep it. Something to consider.

Need to publish solution

Create a sketch that starts with characters randomly scattered (and rotated). Have them slowly move back toward their “home” location. Use an object-oriented approach as seen in Example 17-6.1

One way to solve this is to use interpolation. Interpolation refers to the process of calculating values in between two given pieces of data. In this exercise, we want to know the in-between x locations (and y locations) from the random starting point to the target location in the String. One interpolation method is to simply take the average. Think of it as walking to a wall by always taking a step halfway.
x = (x + targetX)/2; y = (y + targetY)/2;
Another possibility is to simply go 10% of the way there.
x = 0.9_x + 0.l_targetX;
y = 0.9_y + 0.l_targetY;
Processing’s lerp( ) function will do interpolation for you. Visit the reference page for more information: http://processing.org/reference/lerp_.html.
Consider making your sketch interactive. Can you push the letters around using the mouse?