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@Nolski
Created April 19, 2017 02:17
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/**
Copyright 2012 Michael Morris-Pearce
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
(function () {
/* Piano keyboard pitches. Names match sound files by ID attribute. */
var keys =[
'A0', 'Bb0', 'B0',
'C1', 'Db1', 'D1', 'Eb1', 'E1', 'F1', 'Gb1', 'G1', 'Ab1',
'A1', 'Bb1', 'B1',
'C2', 'Db2', 'D2', 'Eb2', 'E2', 'F2', 'Gb2', 'G2', 'Ab2',
'A2', 'Bb2', 'B2',
'C3', 'Db3', 'D3', 'Eb3', 'E3', 'F3', 'Gb3', 'G3', 'Ab3',
'A3', 'Bb3', 'B3',
'C4', 'Db4', 'D4', 'Eb4', 'E4', 'F4', 'Gb4', 'G4', 'Ab4',
'A4', 'Bb4', 'B4',
'C5', 'Db5', 'D5', 'Eb5', 'E5', 'F5', 'Gb5', 'G5', 'Ab5',
'A5', 'Bb5', 'B5',
'C6', 'Db6', 'D6', 'Eb6', 'E6', 'F6', 'Gb6', 'G6', 'Ab6',
'A6', 'Bb6', 'B6',
'C7', 'Db7', 'D7', 'Eb7', 'E7', 'F7', 'Gb7', 'G7', 'Ab7',
'A7', 'Bb7', 'B7',
'C8'
];
/* Corresponding keyboard keycodes, in order w/ 'keys'. */
/* QWERTY layout:
/* upper register: Q -> P, with 1-0 as black keys. */
/* lower register: Z -> M, , with A-L as black keys. */
var codes = [
65, 8, 97,
66, 8, 98, 8, 67, 99, 8, 68, 8, 100, 8, 69,
101, 8, 70, 8, 102, 71, 8, 103, 8, 72, 8, 104,
73, 8, 105, 8, 74, 106, 8, 75, 8,
107, 8, 76,
108, 8, 77, 8, 109, 78, 8, 110, 8, 79, 8, 111,
80, 8, 112, 8, 81, 113, 8, 82, 8,
114, 8, 83,
115, 8, 84, 8, 116, 85, 8, 117, 8,
86, 8, 118,
87, 8, 119, 8, 88, 120, 8, 89, 8,
121, 8, 90,
122
];
var pedal = 32; /* Keycode for sustain pedal. */
var tonic = 'A0'; /* Lowest pitch. */
/* Piano state. */
var intervals = {};
var depressed = {};
/* Selectors */
function pianoClass(name) {
return '.piano-' + name;
};
function soundId(id) {
return 'sound-' + id;
};
function sound(id) {
var it = document.getElementById(soundId(id));
return it;
};
/* Virtual piano keyboard events. */
function keyup(code) {
var offset = codes.indexOf(code);
var k;
if (offset >= 0) {
k = keys.indexOf(tonic) + offset;
return keys[k];
}
};
function keydown(code) {
return keyup(code);
};
function press(key) {
var audio = sound(key);
if (depressed[key]) {
return;
}
clearInterval(intervals[key]);
if (audio) {
audio.pause();
audio.volume = 1.0;
if (audio.readyState >= 2) {
audio.currentTime = 0;
audio.play();
depressed[key] = true;
}
}
$(pianoClass(key)).animate({
'backgroundColor': '#88FFAA'
}, 0);
};
/* Manually diminish the volume when the key is not sustained. */
/* These values are hand-selected for a pleasant fade-out quality. */
function fade(key) {
var audio = sound(key);
var stepfade = function() {
if (audio) {
if (audio.volume < 0.03) {
kill(key)();
} else {
if (audio.volume > 0.2) {
audio.volume = audio.volume * 0.95;
} else {
audio.volume = audio.volume - 0.01;
}
}
}
};
return function() {
clearInterval(intervals[key]);
intervals[key] = setInterval(stepfade, 5);
};
};
/* Bring a key to an immediate halt. */
function kill(key) {
var audio = sound(key);
return function() {
clearInterval(intervals[key]);
if (audio) {
audio.pause();
}
if (key.length > 2) {
$(pianoClass(key)).animate({
'backgroundColor': 'black'
}, 300, 'easeOutExpo');
} else {
$(pianoClass(key)).animate({
'backgroundColor': 'white'
}, 300, 'easeOutExpo');
}
};
};
/* Simulate a gentle release, as opposed to hard stop. */
var fadeout = true;
/* Sustain pedal, toggled by user. */
var sustaining = false;
/* Register mouse event callbacks. */
keys.forEach(function(key) {
$(pianoClass(key)).mousedown(function() {
$(pianoClass(key)).animate({
'backgroundColor': '#88FFAA'
}, 0);
press(key);
});
if (fadeout) {
$(pianoClass(key)).mouseup(function() {
depressed[key] = false;
if (!sustaining) {
fade(key)();
}
});
} else {
$(pianoClass(key)).mouseup(function() {
depressed[key] = false;
if (!sustaining) {
kill(key)();
}
});
}
});
/* Register keyboard event callbacks. */
$(document).keydown(function(event) {
if (event.which === pedal) {
sustaining = true;
$(pianoClass('pedal')).addClass('piano-sustain');
}
var code = event.which;
if (!event.shiftKey) {
code += 32;
}
press(keydown(code));
});
$(document).keyup(function(event) {
var code = event.which;
if (!event.shiftKey) {
code += 32;
}
if (event.which === pedal) {
sustaining = false;
$(pianoClass('pedal')).removeClass('piano-sustain');
Object.keys(depressed).forEach(function(key) {
if (!depressed[key]) {
if (fadeout) {
fade(key)();
} else {
kill(key)();
}
}
});
}
if (keyup(code)) {
depressed[keyup(code)] = false;
if (!sustaining) {
if (fadeout) {
fade(keyup(code))();
} else {
kill(keyup(code))();
}
}
}
});
})();
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