Processing: Creative Coding and Computational Art

manipulation is one area in which bitwise operations are pretty handy, and why I believe
they were included in Processing.
OK, but I still haven’t really told you anything about bitwise operations. To begin to understand
them, you need to think a little about how numbers are represented on the computer,
and to do that you need to go all the way down to the periodic table and the
element silicon. (Oh boy.)
Semiconductors
I suspect by now, most of you realize computers groove on zeros and ones. Why? Well, this
is actually a pretty interesting story (that I will very highly abridge). The brain of the computer,
or the CPU, is made up of a lot of little data processing units called transistors; you
can actually buy CPUs now that have over 1 billion transistors etched onto a 1-inch-square
silicon chip, with wiring over a thousand times thinner than a human hair. (Which maybe
offers some insight into the famous question, “How many angels can fit on the head of a
pin?”) Angels aside, transistors are like little switches that open and close, controlling how
electricity flows.
Silicon, a really common and cheap element (think sand on the beach), has one very significant
property. Its outer shell (we’re on the periodic table now, down at the atomic
level) has four measly electrons that all bond with other nearby silicon atoms, forming
crystal lattice structures.
A somewhat valuable by-product of this tendency to form crystal lattice
structures is the diamond, made from carbon, which is right above silicon on
the periodic table, and has a similar property.
Because all four of silicon’s outer electrons form these perfect bonds, there are no free
electrons roaming around, which is not a good thing in regard to electricity, as electricity
requires these free electrons to flow. So silicon, unlike a metal such as copper, is not considered
a conductor. However, it’s not considered an insulator either (like rubber, for
instance). Instead, silicon is classified as a semiconductor. You’ve probably heard the term
semiconductor before, as the entire computer industry is built on semiconductors. So if
silicon can’t conduct electricity, why do we use it, and what the heck does this all have to
do with color?
There is a process called doping (no, I’m not contesting Lance Armstrong’s seventh Tour
de France win) that allows silicon to be developed into a controllable conductive material.
The controllable part is what is key here. Using doping, it’s possible, applying the right
amount of current to the silicon transistors, to cause them to conduct electricity; you can
think of the process almost like pushing on a hinged gate—the gate stays shut until
enough force is exerted on it. These relatively simple and inexpensive gates are the basis
of computing, and ultimately why we have bitwise operations.
Since the gates can only either be open or closed, you can use just two values to represent
the different possible states of the gate: 1 for open and 0 for closed. A single transistor
MATH REFERENCE
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