Processing: Creative Coding and Computational Art

Figure 6-27. Table Layout II sketch
This was a pretty brute-force and inefficient way to add randomization to the algorithm,
and you should notice all the magic numbers lurking in the line() function calls (yuck).
But running the sketch, you’ll see that things are beginning to get more interesting.
Wouldn’t it be cool if you could do this to HTML table structures (on purpose)? I also
added some more formatting to the code to make it more modular, such as the
drawTable() function.
When you add your own custom functions to Processing, you also need to include
Processing’s setup() function. setup() is executed only once when a sketch launches, and
is a good place to initialize program variables. Since setup(), like all functions, is structured
with external curly braces surrounding a main block, it follows the same rules of
scope as I discussed with for loops—variables declared within the block are only visible
from within the block (they have local scope). If you want variables to be accessible
throughout the entire program, you need to declare them outside of the setup() function,
at the top of the program.
Although functions add another layer of abstraction to your code, they provide tremendous
processing power, as they modularize a process, allowing it to be used like an independent
machine or engine. By utilizing user-defined inputs (parameters) with a function,
the same function can generate a wide range of output possibilities. In the next example, I
added a number of parameters to the drawTable() function, greatly increasing the sketch’s
expressive potential. Three examples of the sketch’s output are shown in Figures 6-28,
6-29, and 6-30.
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