What is your favorite? Pentagon? Hexagon? Heptagon? No? What about the icosagon? The polygon() function created for this example is capable of drawing any regular polygon. Try placing different numbers into the polygon() function calls within draw() to explore.

Highlighted Features

• beginShape()
• endShape()
• vertex()

/**
 * Regular Polygon
 * 
 * What is your favorite? Pentagon? Hexagon? Heptagon? 
 * No? What about the icosagon? The polygon() function 
 * created for this example is capable of drawing any 
 * regular polygon. Try placing different numbers into the 
 * polygon() function calls within draw() to explore. 
 */

void setup() {
  size(640, 360);
}

void draw() {
  background(102);
  
  pushMatrix();
  translate(width*0.2, height*0.5);
  rotate(frameCount / 200.0);
  polygon(0, 0, 82, 3);  // Triangle
  popMatrix();
  
  pushMatrix();
  translate(width*0.5, height*0.5);
  rotate(frameCount / 50.0);
  polygon(0, 0, 80, 20);  // Icosagon
  popMatrix();
  
  pushMatrix();
  translate(width*0.8, height*0.5);
  rotate(frameCount / -100.0);
  polygon(0, 0, 70, 7);  // Heptagon
  popMatrix();
}

void polygon(float x, float y, float radius, int npoints) {
  float angle = TWO_PI / npoints;
  beginShape();
  for (float a = 0; a < TWO_PI; a += angle) {
    float sx = x + cos(a) * radius;
    float sy = y + sin(a) * radius;
    vertex(sx, sy);
  }
  endShape(CLOSE);
}