a pentagon and more - OpenProcessing

mySketch
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// example code adapted from listing 8.4 of Pearson (2011: 173-174)
// draw a pentagon using rotation
// adding midpoint marks
// adding extrusion from midpoint
// schien@mail.ncku.edu.tw, Fall 2020
​
​
let pentagon;
let _strutFactor = 0.2;
​
function setup() {
  createCanvas(600, 600);
  pentagon = new FractalRoot();
  pentagon.drawShape();
}
​
function draw() {
  //empty for now
}
​
// ====== FractalRoot ======
class FractalRoot {
  constructor() {
    this.pArray = [];
    let cx = width/2;
    let cy = height/2;
    for (let i=0; i<360; i+=72) {
      let x = cx+(280*cos(radians(i)));
      let y = cy+(280*sin(radians(i)));
      this.pArray.push(new PointObj(x, y));
    }
    this.rootBranch = new Branch(0, 0, this.pArray);
  }
​
  drawShape() {
    this.rootBranch.drawMe();
  }
}
​
// ====== PointObj ======
class PointObj {
  constructor(ex, ey) {
    this.x = ex;
    this.y = ey;
  }
}
​
// ====== Branch ======
class Branch {
  constructor(lev, n, points) {
    this.level = lev;
    this.num = n;
    this.outerPoints = points;
    this.midPoints = this.calcMidPoints();
    this.projPoints = this.calcProjPoints();
  }
​
  drawMe() {
    strokeWeight(5-this.level);
    for (let i=0; i<this.outerPoints.length; i++) {
      let nexti = i+1;
      if (nexti === this.outerPoints.length) {
        nexti = 0;
      }
      line(this.outerPoints[i].x, this.outerPoints[i].y, this.outerPoints[nexti].x, this.outerPoints[nexti].y);
    }
    strokeWeight(0.5);
    fill(255, 150);
    for (let j=0; j<this.midPoints.length; j++) {
      ellipse(this.midPoints[j].x, this.midPoints[j].y, 15, 15);
      line(this.midPoints[j].x, this.midPoints[j].y, this.projPoints[j].x, this.projPoints[j].y);
      ellipse(this.projPoints[j].x, this.projPoints[j].y, 15, 15);
    }
  }
  
  calcMidPoint(end1, end2) {
    let mx = (end1.x + end2.x)/2;
    let my = (end1.y + end2.y)/2;
    let mp = new PointObj(mx, my);
    return mp;
  }
​
  calcMidPoints() {
    let mpArray = [];
    for (let i=0; i<this.outerPoints.length; i++) {
      let nexti = i+1;
      if (nexti == this.outerPoints.length) {
        nexti = 0;
      }
      let thisMP = this.calcMidPoint(this.outerPoints[i], this.outerPoints[nexti]);
      mpArray.push(thisMP);
    }
    return mpArray;
  }
  
  calcProjPoint(mp, op) {
    let px = mp.x + ((op.x - mp.x) * _strutFactor);
    let py = mp.y + ((op.y - mp.y) * _strutFactor);
    let pp = new PointObj(px, py);
    return pp;
  }
​
  calcProjPoints() {
    let ppArray = [];
    for (let i=0; i<this.midPoints.length; i++) {
      let nexti = (i+3)%this.midPoints.length;
      let thisPP = this.calcProjPoint(this.midPoints[i], this.outerPoints[nexti]);
      ppArray.push(thisPP);
    }
    return ppArray;
  }
}