Processing: Creative Coding and Computational Art

the number, as shown in the following equations—remember that any number raised to
the 0 power is equal to 1—that is, n 0 = 1):
Now let’s go back to the alpha setting in base 2:
The 255 probably rings a bell, as it’s the highest value any of the individual RGBA components
can have.
Bitwise operations to the rescue
Referring back to the Processing reference, if you call the function float r =
red(myColor); by passing in a color argument (which I’m calling myColor), the red value is
pulled out of the color and returned as a float value, which I’m assigning to the float
variable r. Well, a faster way to get the red value is to perform a bitwise operation on the
color. Now you may say, big deal, computers are fast. This is way too confusing to warrant
the little savings in time. However, imagine now you have an image that is 1,500 pixels
times 1,000 pixels (or a total of 1,500,000 pixels) and you want to do a series of manipulations
to all the pixels in the image, and maybe you even want to animate it—well, processing
time is now a huge deal, and the bitwise operators may very well save the day.
Again, here’s the expression float r = red(myColor); handled as a bitwise operation:
float r = myColor >> 16 & 0xFF;
I know this expression must look odd (and maybe even scary) to many of you—it totally
did to me. There are two distinct processes occurring on the integer in this little line of
code. The first process involves the bits of the integer being shifted 16 places to the right
(using >> 16), and after that, a bitwise AND operation (using & 0xFF) is performed, yielding
the isolated red value. I’ll look at each process separately.
Shifting bits
Shifting bits 16 places to the right literally means moving all the bits over 16 places. There
are two different bitwise shift operators in Processing: >> and ) shifts bits
to the right and the second (