Note ratios

Tuning for C major, diatonic scale (white piano keys)

Use different ratios for different scales

C 1/1 ~ D 9/8 ~ E 5/4 ~ F 4/3 ~ G 3/2 ~ A 5/3 ~ B 15/8 ~ C 2/1

*/

​

let notes = [1, 1.125, 1.25, 1.333, 1.5, 1.667, 1.875, 2];

​

let sound;

let colWidth;

let currentCol;

​

function preload() {

  sound = loadSound("gong.mp3");

}

​

function setup() {

  createCanvas(400, 400);

  colorMode(HSB);

  // p5js.org/reference/#/p5.SoundFile/playMode

  sound.playMode("restart"); // try 'sustain'

​

  // set column width according

  // to length of notes' array

  colWidth = width / notes.length;

}

​

function draw() {

  background(220);

​

  for (let col = 0; col < notes.length; col++) {

    let x = col * colWidth;

​

    // if mouse is in a column

    if (mouseX > x && mouseX < x + colWidth) {

      // give it a color

      let hue = col * (360 / notes.length);

      fill(hue, 100, 100);

​

      // play a note

      if (currentCol != col) {

        sound.rate(notes[col])

        // sound.rate(notes[col] * 2)

        sound.play();

        currentCol = col;

      }

    } else {

      fill(255);

    }

    rect(x, 0, colWidth, height);

  }

}

​