// Buffon's Needle Pi Day 2023 Challenge

// https://thecodingtrain.com/challenges/176-buffon-needle

// https://youtu.be/h5ZNcAPXxew

​

// Code:  https://editor.p5js.org/codingtrain/sketches/eMaEGlfmu

​

let count = 3;

​

function setup() {

  createCanvas(720, 360);

  noLoop();

}

​

function mousePressed() {

  redraw();

  // save(`graph${count}.png`);

  count++;

}

​

function draw() {

  clear();

  background(255);

  let buffer = 8;

​

  let x = width / buffer;

  let w = width - (2 / buffer) * width;

  let h = w / PI;

  let y = height - h / 2;

  strokeWeight(2);

  stroke(0);

  line(x, y, x, y - h);

  line(x, y, x + w, y);

​

  noStroke();

  fill(0);

  textFont("courier");

  textSize(24);

  textAlign(CENTER, CENTER);

  text("0", x, y + 20);

  text("π/2", x + w / 2, y + 20);

  text("π", x + w, y + 20);

​

  text("0", x - 20, y);

  text("½", x - 20, y - h / 2);

  text("1", x - 20, y - h);

​

  textSize(48);

  text("θ", x + w + 48, y);

  text("x", x, y - h - 48);

​

  if (count > 0) {

    strokeWeight(2);

    stroke(0);

    fill(45, 197, 244, 150);

    rect(x, y - h / 2, w, h / 2);

  }

​

  strokeWeight(4);

  stroke(0);

  noFill();

  if (count > 1) {

    fill(240, 99, 164);

  }

  beginShape();

  for (let a = 0; a <= PI; a += PI / 20) {

    let px = map(a, 0, PI, x, x + w);

    let py = map((1 / 2) * sin(a), 0, 1, y, y - h);

    vertex(px, py);

  }

  endShape();

​

  strokeWeight(8);

  stroke(0);

  point(x, y);

  point(x + w / 2, y);

  point(x + w, y);

  point(x, y - h / 2);

  point(x, y - h);

}

​