Change default knob value to 0.5. Add vco.js.

examples/hello.js

@@ -29,7 +29,7 @@ function process(args) {
 		var rgb = hsvToRgb(h, 1, 1)
 		args.lights[i] = rgb
 		args.switchLights[i] = rgb
-		args.outputs[i] = Math.sin(2 * Math.PI * h) * 10
+		args.outputs[i] = Math.sin(2 * Math.PI * h) * 5 + 5
 	}
 }
 

examples/vco.js

@@ -0,0 +1,28 @@
+// Voltage-controlled oscillator example
+// by Andrew Belt
+
+// JavaScript isn't ideal for audio generating and processing due to it being 10-100 less efficient than C++, but it's still an easy way to learn simple DSP.
+
+config.frameDivider = 1
+
+var phase = 0
+function process(args) {
+	// Knob ranges from -5 to 5 octaves
+	var pitch = args.knobs[0] * 10 - 5
+	// Input follows 1V/oct standard
+	pitch += args.inputs[0]
+
+	// The relationship between 1V/oct pitch and frequency is `freq = 2^pitch`.
+	// Default frequency is middle C (C4) in Hz.
+	// https://vcvrack.com/manual/VoltageStandards.html#pitch-and-frequencies
+	var freq = 261.6256 * Math.pow(2, pitch)
+	display("Freq: " + freq.toFixed(3) + " Hz")
+
+	// Accumulate phase
+	phase += args.sampleTime * config.frameDivider * freq
+	// Wrap phase around range [0, 1]
+	phase %= 1
+
+	// Convert phase to sine output
+	args.outputs[0] = Math.sin(2 * Math.PI * phase) * 5
+}

src/Prototype.cpp

@@ -43,7 +43,7 @@ struct Prototype : Module {
 	Prototype() {
 		config(NUM_PARAMS, NUM_INPUTS, NUM_OUTPUTS, NUM_LIGHTS);
 		for (int i = 0; i < NUM_ROWS; i++)
-			configParam(KNOB_PARAMS + i, 0.f, 1.f, 0.f, string::f("Knob %d", i + 1));
+			configParam(KNOB_PARAMS + i, 0.f, 1.f, 0.5f, string::f("Knob %d", i + 1));
 		for (int i = 0; i < NUM_ROWS; i++)
 			configParam(SWITCH_PARAMS + i, 0.f, 1.f, 0.f, string::f("Switch %d", i + 1));