Play midi notes using WebMIDI.js

*/

​

let midiVal, midiVelocity, freq, osc, env;

​

WebMidi.enable(function (err) {

    //check if WebMidi.js is enabled

    if (err) {

        console.log("WebMidi could not be enabled.", err);

    } else {

        console.log("WebMidi enabled!");

    }

​

    // name our visible MIDI input and output ports

    console.log("Inputs Ports: ");

    for (i = 0; i < WebMidi.inputs.length; i++) {

        console.log(i + ": " + WebMidi.inputs[i].name);

    }

​

    // choose an input port (0 means use the first device we see)

    inputSoftware = WebMidi.inputs[0];

    // listen to all incoming "note on" input events

    inputSoftware.addListener('noteon', "all",

        function (e) {

            // Play the note recieved

            startSound(e.note.number, e.velocity);

        }

    );

​

    // listen for noteoff events (not used) 

    inputSoftware.addListener('noteoff', "all", function (e) {} );

});

​

function setup() {

    let cnv = createCanvas(640, 480);

    osc = new p5.TriOsc();

    env = new p5.Envelope();

}

​

function draw() {

    background(220);

    text('Note info;', 10, 20);

    if (midiVal) {

        text('MIDI: ' + midiVal, 10, 40);

        text('Freq: ' + freq, 10, 60);

        circle((midiVal * 5) ,(midiVelocity * 3.8), 20);

    }

}

​

function startSound(noteVal, velocityVal) {

    osc.start();

    midiVal = noteVal;

    midiVelocity = velocityVal;

    freq = midiToFreq(noteVal);

    env.setADSR(0.001, velocityVal);

    osc.freq(freq);

    env.ramp(osc, 0, 1.0, 0);

}