Processing: Creative Coding and Computational Art

Figure 6-39. Create 3 Triangles sketch
Polygons and patterns
Now that you have a basic understanding about how the trig functions can be used to
identify a point on a circle, you can exploit that knowledge to generate any regular polygon.
(Even if you don’t yet fully grasp—or even care—how the trig functions work, you
can still use them. In fact, through using them, you’ll get a better understanding of how
they work than through reading about them). The following example incorporates the
beginShape() and endShape(CLOSE) functions in a basic polygon-creation algorithm (the
output is shown in Figure 6-40):
/*
Poly Maker
Ira Greenberg, November 26, 2005
revised October 18, 2006
*/
void setup(){
size(400, 400);
background(0);
smooth();
noFill();
makePoly(width/2, height/2, 9, 150, 255, 8, MITER);
}
void makePoly(int x, int y, int points, float radius, ➥
int strokeCol, float strokeWt, int strokeJn){
float px=0, py=0;
float angle = 0;
stroke(strokeCol);
strokeJoin(strokeJn);
strokeWeight(strokeWt);
beginShape();
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