Processing: Creative Coding and Computational Art

“Operators” will hopefully sound pretty familiar by now. Operators are the basic math
symbols used to do mathematical operations. I’ve been using the most common four (+, -,
+, and /) throughout the book, so I’ll assume you know what these basic operators do. If
not, you can always refer to the “Operators” section of Chapter 3. These symbols can be
used in conjunction with = for assignment operations, as in speed+=.5. I also cover assignment
operations in detail in Chapter 3. % is a strange operator to many people, so it may
need a little more clarification. You might remember that % is called the modulus operator,
and it used to find the remainder of a division operation. For example, 5 % 3 = 2 and 6 %
2 = 0. In the first example, 2 is the remainder of the division; in the second expression,
there is no remainder, so it equals 0. Two other operators that may need a little further
clarification are the increment and decrement operators (++ and --). I’ve used these
throughout the book as well, so you are probably familiar with how they basically work.
What I haven’t covered are the pre and post options when using them. I’ve mostly been
using them on the right side of the operand, as in speed++, but it is perfectly valid to write
the statement as ++speed. However, there is a subtle difference in how these two forms
work. For example, in the following code snippets, the pre increment expression outputs a
7 and the post increment a 6. Why?
Here’s the pre increment code:
int val = 6;
print(++val); //outputs 7
And here’s the post increment version:
int val = 6;
print(val++); //outputs 6
The pre increment performs the incrementation before the print function returns a value,
and the post version does it afterward. If you run a second print statement on the variable,
as follows, you’ll see that it now says 7:
int val = 6;
println(val++); //outputs 6
print(val); //outputs 7
Bitwise Operators
Bitwise operators act at the bit level (down at the zeros and ones), and are especially useful
for efficiently manipulating the individual RGBA color components of pixels. The four
bitwise operators included in Processing are: >> (right shift),