public void draw() {
// draw image each frame
image(img, 0, 0);
// check if note is white or black
// because the image is greyscale I can do this by only checking one of the colour values of
// each pixel.
// the algorithm is designed so that each row of 'barcode' in the image only gets read once.
// if the note is white, set a low note, if black set a high note.
if (red(img.pixels[(counter % 214) + (counter / 214) * 9]) > 127) {
note = 48;
} else {
note = 84;
}
// draw a point to track where the cursor is in the image.
point(counter % 214, counter / 214 * 9 + 3);
// play the note on the synth for the duration required for 120 bpm, treating each note as a
// semiquaver
synth.play(note, 100, 125);
// incrmement counter
counter = (counter + 2);
// if we've gone past the end of the image, exit the program.
if ((counter % 214) + (counter / 214) * 9 > img.width * img.height) {
exit();
}
}
public void stop() {
synth.close();
exit();
}