65 lines
2.0 KiB
JavaScript
65 lines
2.0 KiB
JavaScript
// setup audio context
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const AudioContextConstructor = window.AudioContext || window.webkitAudioContext;
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const Context = new AudioContextConstructor();
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// create audio nodes
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const Oscillator = Context.createOscillator();
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const GainVolume = Context.createGain();
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const GainBeep = Context.createGain();
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const GainLeft = Context.createGain();
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const GainRight = Context.createGain();
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const ChannelMerge = Context.createChannelMerger(2);
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// wire up audio nodes
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Oscillator.connect(GainVolume);
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GainVolume.connect(GainBeep);
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GainBeep.connect(GainLeft);
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GainBeep.connect(GainRight);
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GainLeft.connect(ChannelMerge, 0, 0);
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GainRight.connect(ChannelMerge, 0, 1);
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ChannelMerge.connect(Context.destination);
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// start
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GainBeep.gain.value = 0;
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GainLeft.gain.value = 0;
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GainRight.gain.value = 0;
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GainVolume.gain.value = 0;
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Oscillator.start(Context.currentTime+0.0);
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const pad = 0.0015;
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/** @type {(inNode:AudioParam, inValue:number, inDelay:number)=>AudioParam} */
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const change = (inNode, inValue, inDelay) => inNode.linearRampToValueAtTime(inValue, Context.currentTime+inDelay);
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/** @type {(inNode:AudioParam, inStart:number, inDuration:number)=>void} */
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const pulse = (inNode, inStart, inDuration) =>
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{
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change(inNode, 0, inStart);
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change(inNode, 1, inStart+pad);
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change(inNode, 1, (inStart+inDuration)-pad );
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change(inNode, 0, (inStart+inDuration) );
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};
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/** @type {(inContinuous:boolean, inChannel:number, inFreq:number, indBHL:number)=>void} */
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export const Play = (inContinuous, inChannel, inFreq, indBHL) =>
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{
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Context.resume();
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GainBeep.gain.cancelScheduledValues(Context.currentTime);
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GainBeep.gain.setValueAtTime(0, Context.currentTime);
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change(GainLeft.gain, 1-inChannel, pad);
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change(GainRight.gain, inChannel, pad);
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change(Oscillator.frequency, inFreq, pad);
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change(GainVolume.gain, indBHL, pad);
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if (inContinuous)
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{
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pulse(GainBeep.gain, 0.01, 0.8);
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}
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else
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{
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pulse(GainBeep.gain, 0.01, 0.2);
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pulse(GainBeep.gain, 0.33, 0.2);
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pulse(GainBeep.gain, 0.66, 0.2);
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}
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}; |