Processing: Creative Coding and Computational Art

PROCESSING: CREATIVE CODING AND COMPUTATIONAL ART
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You might be curious as to why you can get 256 unique values from a single byte (8
bits) of memory. If you get scared by this explanation, don’t worry. It’s not essential to
know! It’s because in base 2 (as opposed to the base 10 system our minds are accustomed
to), a byte is an 8-digit binary number, made up only of a combination of zeros
and ones. The number of distinct values of a binary number can be calculated by taking
2—only two possible values for each digit, 0 or 1—and raising it to the power of
the number of places or digits in the number. So 2 to the 8th power equals 256. ints
can hold up to 4 bytes (or 2 to the 32nd power), and thus can hold numbers between
–2,147,483,648 and 2,147,483,647. If you’ve been involved in digital design for some
time, you’ve probably converted images from 24-bit color to 8-bit color, going from 2
to the 24th power, or 16,777,216 possible colors, to 2 to the 8th power, or 256 possible
colors. The old web-safe palette of 216 colors was just a subset of the 8-bit palette
that looked somewhat consistent on different platforms/browsers.
When you write the variable data type and identifier (name)—for example, int
ballCount—you refer to this as declaring the variable. When you give a variable a specific
value—for example, ballCount = 3—then you say you are initializing the variable. These
two activities can be done together in one step (e.g., int ballCount = 3), or separately,
depending upon your program needs. Because variables are by default mutable, once you
initialize a variable you can still change its value whenever you need to (as long as
you assign it a value consistent with its originally declared data type). For example, try running
the following code:
int ballCount = 15;
println(ballCount);
ballCount = 10;
println(ballCount);
ballCount = 100;
println(ballCount);
When you run this sketch, you’ll get the following output:
15
10
100
Strict typing
I remember first learning Java and being confused that I had to keep writing the data types
as I declared my variables, not to mention the whole case-sensitivity issue. I was used to
old-school ActionScript, where variables could hold anything at any time. However, I’ve
come to understand and appreciate the benefits of what’s referred to as “strict typing” of
variables. Interestingly, ActionScript, which some of you may know, now uses explicit typing
of variables as well—so much for the good old days. So int ballCount can only hold
integer values and float ballSpeed can only hold float values. But why is this helpful?