Processing: Creative Coding and Computational Art

PROCESSING: CREATIVE CODING AND COMPUTATIONAL ART
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These operations are so common in programming that there is a shortcut syntax more
commonly used. The shortcut simply joins the mathematical and assignment operators.
For example, the last expression (y = y / 1.25;) could be shortened to the following:
y /= 1.25;
The other mathematical operations follow the same structure. Here are some examples:
float temp = 98.6;
temp += 5; // temp now equals: 103.6
temp -= .6; // temp now equals: 103
temp *= 2; // temp now equals: 206
temp %= 23; // temp now equals: 22
The last expression may look odd; it’s using the modulus operator. Remember, modulus
returns the remainder of division; 23 goes into 206 eight times, leaving a remainder of 22,
which then gets assigned back to the temp variable.
In the assignment operations you’ve been looking at thus far, the operator(s) have been
surrounded by two operands. The geeky way to refer to these types of operators is as
binary operators. Processing also uses some operators that only require one operand,
which are referred to as unary operators. Two of these very useful operators are actually
shortcuts for two other shortcuts.
If I want to add 1 to the int variable x using the shortcuts just shown, I could write the
following:
x += 1;
Using a unary operator, the expression can be shortened to the following:
x++;
You’ll also see this expression written as ++x;. It does matter, in some contexts, on which
side you put the two operators, which I’ll discuss the subtlety of later on. Besides incrementing
by one, you can also decrement by one, using x-- (also --x). I recommend learning
to use the shortcuts as soon as you can—they will save you keystrokes (possibly staving
off carpal tunnel) and make you look like you’ve been coding for years.
Conditionals
Next, I want to cover conditional statements, which you got a sneak peak of when you
looked at the relational and conditional operators. A conditional statement is sometimes
referred to as a decision statement. Essentially, is says that if a certain condition is true,
then do something; but if it is not true, do something else.
I think by now you’re probably in need of some visual digression, so we’ll cover the conditionals
by creating a little sketch (see Figure 3-3), which creates a bouncing ball: