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<!DOCTYPE html>
<html>
<head>
<title>WebAudio Csound</title>
<style type="text/css">
html, body {
font-family: Monospace;
color: #bf94f7;
background-color: #000055;
}
#console {
font-family: Monospace;
color: #b5b6ff;
background-color: #000000;
font-size: 16px;
width: 805px;
display: flex;
align-items: center;
justify-content: center;
border-style: solid;
padding: 20px 0px;
}
H1 {
font-size: 36px;
}linenr
button {
margin: auto;
font-family: Monospace;
width: 155px;
padding: 10px 10px;
font-size: 24px;
background-color: #b5b6ff;
}
</style>
<script type="text/javascript" src="js/csound.js"></script>
<script type="text/javascript">
function WebMIDI_init(midi_handle) {
var haveDevs = false;
var devs = midi_handle.inputs.values();
for ( var m = devs.next(); m && !m.done; m = devs.next()) {
m.value.onmidimessage = onMIDIEvent;
haveDevs = true;
}
if (!haveDevs)
console.log("No MIDIDevs");
else {
console.log("WebMIDI support enabled");
}
}
function WebMIDI_err(err) {
console.log("Error starting WebMIDI");
}
function onMIDIEvent(event) {
switch (event.data[0] & 0xf0) {
case 0x90:
if (event.data[2]!=0) {
csound.NoteOn(1, event.data[1], event.data[2]);
return;
}
case 0x80:
csound.NoteOff(1, event.data[1], event.data[2]);
return;
}
}
// called by csound.js
function moduleDidLoad() {
csound.Play();
csound.CompileOrc(
`massign 1,1
instr 1
icps = cpsmidi()
chnset icps, \"freq\"
k1 linenr 0.5,0.01,0.1, 0.01
a1 oscili k1, icps
outs a1,a1
endin`);
if (navigator.requestMIDIAccess)
navigator.requestMIDIAccess().then(WebMIDI_init,
WebMIDI_err);
else
console.log("No WebMIDI support");
}
function attachListeners() {
var notes = ['c', 'd', 'e', 'g', 'a'];
for (i = 0; i < notes.length; i++) {
document.getElementById(notes[i]).
addEventListener("mousedown", Play);
document.getElementById(notes[i]).
addEventListener("mouseup", Stop);
document.getElementById(notes[i]).
addEventListener("mouseleave", Stop);
document.getElementById(notes[i]).
addEventListener("touchstart", Play);
document.getElementById(notes[i]).
addEventListener("touchend", Stop);
document.getElementById(notes[i]).
addEventListener("touchmove", Stop);
}
}
var count = 0;
function handleMessage(message) {
var element = document.getElementById('console');
element.value += message;
element.scrollTop = 99999; // focus on bottom
count += 1;
if (count == 1000) {
element.value = ' ';
count = 0;
}
}
var started = false;
var playing = false;
// click handler
function Play(event) {
event.preventDefault();
if (started == false) {
CsoundObj.CSOUND_AUDIO_CONTEXT.resume();
started = true;
}
let note = event.target.value;
csound.NoteOn(1, note, 60);
playing = true;
}
function Stop(event) {
event.preventDefault();
if (playing) {
let note = event.target.value;
csound.NoteOff(1, note, 60);
playing = false;
}
}
</script>
</head>
<body>
<H1> Virtual MIDI Keys </H1>
<p>
<button id="c" value=60>C</button>
<button id="d" value=62>D</button>
<button id="e" value=64>E</button>
<button id="g" value=67>G</button>
<button id="a" value=69>A</button>
</p>
<textarea class="console" rows="20" id="console">Csound: not loaded</textarea>
</body>
</html>
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