Processing: Creative Coding and Computational Art

Figure 7-13. Damping effect on curves
In the last chapter, I demonstrated a scribble function, where endpoints of a line were sent
to a function that randomly jittered points between the terminal points, creating a more
organic-looking line. You can use trig functions in a similar capacity. I thought it might be
interesting to put the particle effect together with the trig function to create particle
waves (see Figure 7-14); it will also be a good review of using custom functions.
This is a fairly complex sketch. Each part of it is encapsulated in a function, and there are
no global variables. Thus, the individual functions speak to each other through function
calls. I recommend playing with the sketch for a while before reviewing the code. I completely
parameterized the main particle function, so it’s easy to mess with the variables
in the setup() structure—seeing how the changes affect the output, as illustrated in
Figure 7-15—before diving into the code guts.
/*
Particle Wave
Ira Greenberg, December 5, 2005
revised January 26, 2007
*/
void setup(){
size(800, 400);
background(0);
smooth();
/*lots of stuff to manipulate. I packed
the arguments into arrays just to make the
setParticles function argument/parameter
lists less unwieldy*/
//particle style
/* increase strokeWt if
you don't see any output*/
float strokeWt = 1.5;
float strokeCol= 255;
float[]strokeStyle = { strokeWt, strokeCol };
CURVES
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