Processing: Creative Coding and Computational Art

frame. The loop keeps running and keeps assigning 3 to recty.x, so she doesn’t move
(poor recty), even though the frame is being refreshed continuously. So why do people do
this (besides just to annoy their teachers)? I think it’s because it is so easy for us to understand
how to move that we don’t waste any brain cells thinking about it.
Let’s imagine you and I were standing across a room from one another and I’d like you to
come join me on my side of the room. More than likely, I’d just say “please come over
here.” Your brain would fill in all the details on how to pull this off, which it would then
communicate to your body and you’d begin walking across the room, most likely in a
direct path toward me. Even though I didn’t tell you a rate or direction to move, you’d
know exactly what to do. Of course, my one-year-old daughter would probably not
respond to the same verbal cue. However, if I held up a shiny object from across the room,
she’d likely begin crawling over to me, also in a straight path no less. One of our challenges
in programming is thinking beneath our intelligence. Although moving across a room may
seem like a really simple task, there are a tremendous number of assumptions and calculations
we make to achieve it, not to mention some pretty insane physics. When we model
even simple behavior on the computer, we need to account for these assumptions—which
is difficult. The correct solution to the movement problem is the following expression:
recty.x = recty.x + speed
Now this expression often looks a little confusing to people in the beginning. Why would
something be equal to itself? It seems illogical. First of all, in programming, the symbol =
doesn’t mean equals, but rather assignment. The symbol == means equals—I know this
seems weird. It might help if I write in English what’s going on in the expression recty.x =
recty.x + speed: “Add the value of the variable speed to recty’s current x property, then
assign that value back to recty’s x property, and then do it again and again. . .” Thus, after
each loop cycle, recty’s x property will increment by 3. By writing the logic out as an algorithm,
you can better understand what’s happening. In this case, recty.x keeps increasing
each loop cycle of the program, moving her across the screen. Will recty stop when she
hits the end of the frame? Nope, we didn’t tell her to. In fact, recty would continue moving
until we quit the program, but of course you won’t see her, because she’s out of the
frame. If this is still unclear, don’t worry at all. This is difficult stuff to begin to get your
head around. Another trick to help you understand this stuff is to do the calculations manually.
For example
Remember speed equals 3.
Start recty.x out at 0.
First, loop recty.x = recty.x +speed.
Now recty.x equals 3.
Second, loop recty.x = recty.x +speed.
Now, recty.x equals 6.
Third, loop recty.x = recty.x +speed.
Now recty.x equals 9.
See the pattern.
CREATIVE CODING
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