a noisy spiral (2025)

// make source code public

// schien@mail.ncku.edu.tw, Spring 2025

//

// the baby-step way to draw a circle

// program for lectures on "The Wrong Way to Draw a Circle"

// schien@mail.ncku.edu.tw

// Fall 2018

//

// adjusted for let/var differenciation (prefer let scoping)

// schien@mail.ncku.edu.tw, Spring 2023

//

// adjusted canvas, circle sizes

// schien@mail.ncku.edu.tw, Spring 2024

//

// turn it into a noisy spiral

// schien@mail.ncku.edu.tw, Spring 2024

//

​

function setup() {

  createCanvas(800, 800);

  noLoop();

​

}

​

function draw() {

  background(255);

  strokeWeight(4);

  noFill();

​

  let radius = 30;

  let centerX = width / 2;

  let centerY = height / 2

​

  // the easy way

  stroke(0, 30);

  circle(centerX, centerY, 2 * radius);

​

  // in steps

  stroke(20, 50, 70);

  let x, y, rad = 0;

  let xn, yn, radn = 0;

  let radiusNoise = random(10);

  for (let ang = 0; ang < 360 * 9; ang += 5) {

    radius += 1;

    radiusNoise += 0.05;

    let thisR = radius + noise(radiusNoise) * 200 - 100;

    if (radn == rad) {

      rad = radians(ang);

      x = centerX + thisR * cos(rad);

      y = centerY + thisR * sin(rad);

    }

    //point(x, y);

    radn = radians(ang + 5);

    xn = centerX + thisR * cos(radn);

    yn = centerY + thisR * sin(radn);

    line(x, y, xn, yn);

    x = xn;

    y = yn;

  }

}