// https://creativecommons.org/licenses/by-sa/4.0/

// Title: Collatz Sea Tree

// Author: Juan Carlos Ponce Campuzano, @PonceCampuzano

// Created: Oct. 29, 2019

// Web editor: https://editor.p5js.org/jcponce/sketches/vh0HVREJH

//

// Forked from:

//   https://editor.p5js.org/codingtrain/sketches/XjLDE7gu6

//   by Daniel Shiffman

//   https://thecodingtrain.com/CodingInTheCabana/002-collatz-conjecture.html

//   https://youtu.be/EYLWxwo1Ed8

​

let start = 1;

let reset = start;

let angle;

let inc = 300;

let len, sw;

​

let colRed, colBlue, colGreen;

let message = true;

​

function setup() {

  createCanvas(innerWidth, innerHeight);

  background(0);

  colorMode(RGB, 1, 1, 1, 1);

​

  let minDimension = min(width, height);

​

  sw = map(minDimension, 300, 1000, 2, 7);

  strokeWeight(sw);

​

  len = map(minDimension, 300, 1000, 3, 8);

​

  angle = random(-0.25, 0.25);

​

  colRed = random(0, 1);

  //colBlue = random(0, 1);

  colGreen = random(0, 1);

​

  cursor(HAND);

​

  document.getElementById("saveI").onclick = () => {

    saveImage();

  }

}

​

function draw() {

  if (message) {

    fill(0);

    noStroke();

    rect(0, 0, width, height * 0.25);

    textSize(24);

    fill(255);

    textAlign(CENTER);

    noStroke();

    text("Click mouse to toggle", width / 2, height * 0.2);

  }

  drawMyplant();

}

​

function collatz(n) {

  // even

  if (n % 2 == 0) {

    return n / 2;

    // odd

  } else {

    return (n * 3 + 1) / 2;

  }

}

let sequence;

​

function drawMyplant() {

  sequence = [];

  let n = start;

  do {

    sequence.push(n);

    n = collatz(n);

  } while (n != 1);

  sequence.push(1);

  sequence.reverse();

​

  resetMatrix();

  translate(width / 2, height);

  for (let j = 0; j < sequence.length; j++) {

    let value = sequence[j];

    if (value % 2 == 0) {

      rotate(angle);

    } else {

      rotate(-angle);

    }

    stroke(colRed, j / sequence.length, colGreen, 0.07);

    let w = map(j / sequence.length, 0, 1, 15, 0.5);

    strokeWeight(w);

    line(0, 0, 0, -len);

    translate(0, -len);

  }

  start += inc;

​

  // reset the starting number before it gets too large

  if (start > 50000) {

    reset++;

    start = reset;

  }

​

  if (mouseIsPressed && mouseY > 45) {

    if (mouseButton == LEFT) {

      background(0);

    }

  }

}

​

function touchStarted() {

  if (mouseButton == LEFT && mouseY > 45) {

    message = false;

    angle = random(-0.25, 0.25);

    colRed = random(0, 1);

    //colBlue = random(0, 1);

    colGreen = random(0, 1);

    sequence.length = 0;

  }

}

​

function mousePressed() {

  if (mouseButton == LEFT && mouseY > 45) {

    message = false;

    angle = random(-0.25, 0.25);

    colRed = random(0, 1);

    //colBlue = random(0, 1);

    colGreen = random(0, 1);

    sequence.length = 0;

  }

}

​

function saveImage() {

  save('collatz.jpg');

}

​