Noise generator, for #54

static/index.html

@@ -269,6 +269,29 @@
 							</div>
 						</div>
 		
+						<div class="field is-horizontal">
+							<div class="field-label">
+								<label class="label">
+									<span data-i18n="label.gain">noise</span>:
+									<output for="noiseGain"></output>%
+									<i class="mdi mdi-volume-off muted"></i>
+								</label>
+							</div>
+							<div class="field-body">
+								<div class="field">
+									<div class="control">
+										<input
+											id="noiseGain"
+											type="range"
+											min="0"
+											max="100"
+											value="0"
+											step="1">
+									</div>
+								</div>
+							</div>
+						</div>
+
 						<div class="field is-horizontal">
 							<div class="field-label">
 								<label class="label">

static/scripts/noise.mjs

@@ -1,35 +1,123 @@
+import {AudioSource, AudioContextTime} from "./audio.mjs"
 
 /**
- * Create a noise generator with a low pass filter
+ * Create a white noise generator with a biquad filter
  * 
  * @param {AudioContext} context Audio context
- * @param {Number} lowpassFreq Low-pass filter frequency (Hz)
- * @returns {GainNode} Gain object for noise
+ * @returns {BiquadFilterNode} Noise filter
  */
- function Noise(context, lowpassFreq = 100) {
+ function WhiteNoise(context) {
     let bufferSize = 17 * context.sampleRate
-    let noiseBuffer = context.createBuffer(1, bufferSize, context.sampleRate)
+    let noiseBuffer = new AudioBuffer({
+        sampleRate: context.sampleRate,
+        length: bufferSize,
+    })
     let output = noiseBuffer.getChannelData(0)
     for (let i = 0; i < bufferSize; i++) {
-        output[i] = Math.random() * 2 - 1;
+        output[i] = Math.random() * 2 - 1
     }
     
-    let whiteNoise = context.createBufferSource();
-    whiteNoise.buffer = noiseBuffer;
-    whiteNoise.loop = true;
-    whiteNoise.start(0);
+    let whiteNoise = context.createBufferSource()
+    whiteNoise.buffer = noiseBuffer
+    whiteNoise.loop = true
+    whiteNoise.start(0)
 
-    let filter = context.createBiquadFilter()
-    filter.type = "lowpass"
-    filter.frequency.value = lowpassFreq
+    let noiseFilter = new BiquadFilterNode(context, {type: "bandpass"})
+    whiteNoise.connect(noiseFilter)
 
-    let gain = context.createGain()
-    gain.gain.value = 0.1
+    return noiseFilter
+}
 
-    whiteNoise.connect(filter)
-    filter.connect(gain)
+class Noise extends AudioSource {
+    /**
+     * 
+     * @param {AudioContext} context 
+     */
+    constructor(context, noises=2) {
+        super(context)
 
-    return gain
+        this.whiteNoise = []
+        
+        for (let i = 0; i < noises; i++) {
+            let wn = {
+                modulator: new OscillatorNode(context),
+                modulatorGain: new GainNode(context),
+                filter: WhiteNoise(context),
+                filterGain: new GainNode(context),
+            }
+
+            wn.modulator.frequency.value = 0
+            wn.modulatorGain.gain.value = 0
+            wn.filter.frequency.value = 800
+            wn.filterGain.gain.value = 0.8 / noises
+    
+            wn.modulator.connect(wn.modulatorGain)
+            wn.modulatorGain.connect(wn.filter.frequency)
+            wn.filter.connect(wn.filterGain)
+            wn.filterGain.connect(this.masterGain)
+
+            wn.modulator.start()
+            this.whiteNoise.push(wn)
+        }
+
+        this.SetNoiseParams(0, 0.07, 70, 400, 0.4)
+        this.SetNoiseParams(1, 0.03, 200, 1600, 0.4)
+        this.masterGain.gain.value = 0.5
+    }
+
+    /**
+     * Set modulator frequency
+     * 
+     * You probably want this to be under 1Hz, for a subtle sweeping effect
+     * 
+     * @param {Number} n Which noise generator
+     * @param {Number} frequency Frequency (Hz)
+     */
+    SetNoiseModulator(n, frequency) {
+        this.whiteNoise[n].modulator.frequency.value = frequency
+    }
+
+    /**
+     * Set modulator depth
+     *
+     * The output of the modulator [-1,1] is multiplied this and added to the
+     * base frequency of the filter.
+     *
+     * @param {Number} n Which noise generator
+     * @param {Number} depth Depth of modulation
+     */
+    SetNoiseDepth(n, depth) {
+        this.whiteNoise[n].modulatorGain.gain.value = depth
+    }
+
+    /**
+     * Set noise filter base frequency
+     * 
+     * @param {Number} n Which noise generator
+     * @param {Number} frequency Frequency (Hz)
+     */
+    SetNoiseFrequency(n, frequency) {
+        this.whiteNoise[n].filter.frequency.value = frequency
+    }
+
+    /**
+     * Set gain of a noise generator
+     * 
+     * @param {Number} n Which noise generator
+     * @param {Number} gain Gain level (typically [0-1])
+     */
+    SetNoiseGain(n, gain) {
+        this.whiteNoise[n].filterGain.gain.value = gain
+    }
+
+    SetNoiseParams(n, modulatorFrequency, depth, baseFrequency, gain) {
+        this.SetNoiseModulator(n, modulatorFrequency)
+        this.SetNoiseDepth(n, depth)
+        this.SetNoiseFrequency(n, baseFrequency)
+        this.SetNoiseGain(n, gain)
     }
 }
 
+export {
+    Noise,
+}

static/scripts/vail.mjs

@@ -7,6 +7,7 @@ import * as I18n from "./i18n.mjs"
 import * as time from "./time.mjs"
 import * as Music from "./music.mjs"
 import * as Icon from "./icon.mjs"
+import * as Noise from "./noise.mjs"
 
 const DefaultRepeater = "General"
 
@@ -46,6 +47,12 @@ class VailClient {
 		// Outputs
 		this.outputs = new Outputs.Collection(globalAudioContext)
 		this.outputs.connect(globalAudioContext.destination)
+
+		// Noise
+		this.noise = new Noise.Noise(globalAudioContext)
+		this.noise.connect(globalAudioContext.destination)
+
+		// App icon
 		this.icon = new Icon.Icon()
 
 		// Keyers
@@ -90,6 +97,9 @@ class VailClient {
 		this.inputInit("#masterGain", e => {
 			this.outputs.SetGain(e.target.value / 100)
 		})
+		this.inputInit("#noiseGain", e => {
+			this.noise.SetGain(e.target.value / 100)
+		})
 		let toneTransform = {
 			note: Music.MIDINoteName,
 			freq: Music.MIDINoteFrequency,