// The Coding Train / Daniel Shiffman

// https://thecodingtrain.com/CodingChallenges/167-prime-spiral.html

// https://youtu.be/a35KWEjRvc0

​

// Prime Spiral: https://editor.p5js.org/codingtrain/sketches/0Ud-XsaYb

// Number Spiral: https://editor.p5js.org/codingtrain/sketches/Zs65bV-Al

// Prime vs Random Spiral: https://editor.p5js.org/codingtrain/sketches/3np1hBlXD

// Shapes and Color: https://editor.p5js.org/codingtrain/sketches/mCvvSKpZ5

// Prime Spiral 3D: https://editor.p5js.org/codingtrain/sketches/-eX078HZ5

​

let x, y;

let px, py;

let step = 1;

let numSteps = 1;

let state = 0;

let turnCounter = 1;

let totalSteps;

​

class Spiral {

  constructor(x, y, w, h) {

    this.stepSize = 5;

    this.pos = createVector(x, y);

    const cols = w / this.stepSize;

    const rows = h / this.stepSize;

    this.totalSteps = cols * rows;

    this.x = 0;

    this.y = 0;

    this.px = this.x;

    this.py = this.y;

    this.step = 1;

    this.numSteps = 1;

    this.turnCounter = 1;

    this.state = 0;

  }

​

  update(testFunction) {

    push();

    translate(this.pos.x, this.pos.y);

    noStroke();

    if (testFunction(this.step)) {

      fill(255);

      circle(this.x, this.y, this.stepSize * 0.75);

    } else {

      fill(50);

      circle(this.x, this.y, this.stepSize * 0.75);

    }

    strokeWeight(1);

    stroke(255, 50);

    //line(this.x, this.y, this.px, this.py);

    pop();

    this.px = this.x;

    this.py = this.y;

​

    switch (this.state) {

      case 0:

        this.x += this.stepSize;

        break;

      case 1:

        this.y -= this.stepSize;

        break;

      case 2:

        this.x -= this.stepSize;

        break;

      case 3:

        this.y += this.stepSize;

        break;

    }

​

    if (this.step % this.numSteps == 0) {

      this.state = (this.state + 1) % 4;

      this.turnCounter++;

      if (this.turnCounter % 2 == 0) {

        this.numSteps++;

      }

    }

    this.step++;

​

    if (this.step > this.totalSteps) {

      noLoop();

    }

  }

}

​

function isRandom(value) {

  return random(1) < 1 / log(value);

}

​

function isPrime(value) {

  if (value == 1) return false;

  for (let i = 2; i <= sqrt(value); i++) {

    if (value % i == 0) {

      return false;

    }

  }

  return true;

}

​

let spiral1, spiral2;

function setup() {

  createCanvas(1000, 550);

  textFont("Courier-Bold");

  background(51);

  spiral1 = new Spiral(250, 250, 465, 465);

  spiral2 = new Spiral(750, 250, 465, 465);

    rectMode(CENTER);

  stroke(255);

  fill(0);

  rect(250, 250, 465, 465);

  rect(750, 250, 465, 465);

  fill(255);

  textSize(32);

  textAlign(CENTER);

  noStroke();

  text("prime", 250, 525);

  text("random", 750, 525);

}

​

function draw() {

  // textSize(stepSize);

  // textAlign(CENTER, CENTER);

  //text(step, x, y);

  //frameRate(1);

  for (let i = 0; i < 10; i++) {

    spiral1.update(isPrime);

    spiral2.update(isRandom);

  }

}

​