mirror of https://github.com/nealey/vail.git
36 lines
942 B
JavaScript
36 lines
942 B
JavaScript
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/**
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* Create a noise generator with a low pass filter
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*
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* @param {AudioContext} context Audio context
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* @param {Number} lowpassFreq Low-pass filter frequency (Hz)
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* @returns {GainNode} Gain object for noise
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*/
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function Noise(context, lowpassFreq = 100) {
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let bufferSize = 17 * context.sampleRate
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let noiseBuffer = context.createBuffer(1, bufferSize, context.sampleRate)
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let output = noiseBuffer.getChannelData(0)
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for (let i = 0; i < bufferSize; i++) {
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output[i] = Math.random() * 2 - 1;
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}
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let whiteNoise = context.createBufferSource();
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whiteNoise.buffer = noiseBuffer;
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whiteNoise.loop = true;
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whiteNoise.start(0);
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let filter = context.createBiquadFilter()
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filter.type = "lowpass"
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filter.frequency.value = lowpassFreq
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let gain = context.createGain()
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gain.gain.value = 0.1
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whiteNoise.connect(filter)
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filter.connect(gain)
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return gain
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}
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}
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