61 lines
1.5 KiB
JavaScript
61 lines
1.5 KiB
JavaScript
// let freq = 440
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const tons = [264, 275, 297, 316.8, 330, 352, 371.25, 396, 412.5, 440, 475.2, 495]
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// const tons = [396, 417, 528. 639, 741, 852, 963]
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/*
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* Play one note
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*/
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note = (context, freq, counter) => {
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// console.log("Note n°", counter, freq)
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const oscil = context.createOscillator()
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oscil.type = 'triangle'
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oscil.frequency.value = freq
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const gainNode = context.createGain()
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oscil.connect(gainNode)
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gainNode.connect(context.destination)
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const notesPerSecond = 5 // In Hertz
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// All are in seconds
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const start = counter / notesPerSecond
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const duration = 1.2 / notesPerSecond
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const ramp = .2 / notesPerSecond / 3 // Exponential increase
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// Increase volume
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gainNode.gain.setTargetAtTime(1, start, ramp)
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// Decrease volume
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gainNode.gain.setTargetAtTime(0, start + duration - ramp * 3, ramp)
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oscil.start(start)
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oscil.stop(start + duration)
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}
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/*
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* From the current URL generate an UUID
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*/
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getUuidFromUrl = () =>
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document.location.pathname
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.split('')
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.reverse()
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.filter(l => l.match(/[0-9a-f]/))
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.join('')
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/*
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* Launch notes based on the current URL
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*/
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launchNotes = (event, counter = 0, uuid = getUuidFromUrl()) => {
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if (counter >= uuid.length || counter >= 5) return
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const context = new AudioContext()
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const freq = tons[parseInt(uuid[counter], 16) % tons.length] / 2
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// freq *= Math.max(1, parseInt(uuid[counter], 16)) / Math.max(1, parseInt(uuid[counter + 1], 16))
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// freq = Math.min(2000, Math.round(freq))
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note(context, freq, counter)
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launchNotes(event, counter + 1, uuid)
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}
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