Clean up VuMeter2.

include/dsp/digital.hpp

@@ -143,6 +143,10 @@ struct Counter {
 		period = 1;
 	}
 
+	void setPeriod(int period) {
+		this->period = period;
+	}
+
 	/** Returns true if the counter reaches `period` and resets. */
 	bool process() {
 		if (++count >= period) {

include/dsp/vumeter.hpp

@@ -33,22 +33,44 @@ struct VuMeter {
 DEPRECATED typedef VuMeter VUMeter;
 
 
+/** Models a VU meter with smoothing.
+Supports peak and RMS (root-mean-square) metering
+Usage example for a strip of lights with 3dB increments:
+
+	// Update VuMeter state every frame.
+	vuMeter.process(deltaTime, output);
+	// Iterate lights every ~512 frames (less than a screen refresh).
+	for (int i = 0; i < 6; i++) {
+		float b = vuMeter.getBrightness(-3.f * (i + 1), -3.f * i);
+		// No need to use setSmoothBrightness() since VuMeter2 smooths the value for you.
+		lights[i].setBrightness(b);
+	}
+*/
 struct VuMeter2 {
 	enum Mode {
 		PEAK,
 		RMS
 	};
 	Mode mode = PEAK;
-	float v = 0.f;
+	/** Either the smoothed peak or the mean-square of the brightness, depending on the mode. */
+	float v;
 	/** Inverse time constant in 1/seconds */
-	float lambda = 0.f;
+	float lambda = 30.f;
+
+	VuMeter2() {
+		reset();
+	}
 
 	void reset() {
 		v = 0.f;
 	}
 
 	void process(float deltaTime, float value) {
-		if (mode == PEAK) {
+		if (mode == RMS) {
+			value = std::pow(value, 2);
+			v += (value - v) * lambda * deltaTime;
+		}
+		else {
 			value = std::abs(value);
 			if (value >= v) {
 				v = value;
@@ -57,22 +79,18 @@ struct VuMeter2 {
 				v += (value - v) * lambda * deltaTime;
 			}
 		}
-		else {
-			value = std::pow(value, 2);
-			v += (value - v) * lambda * deltaTime;
-		}
 	}
 
 	/** Returns the LED brightness measuring tick marks between dbMin and dbMax.
 	For example, `getBrightness(-6.f, 0.f)` will be at minimum brightness at -6dB and maximum brightness at 0dB.
-	Set dbMin == dbMax == 0.f for a clip indicator.
+	Set dbMin == dbMax == 0.f for a clip indicator that turns fully on when db >= dbMax.
 	Expensive, so call this infrequently.
 	*/
 	float getBrightness(float dbMin, float dbMax) {
 		float db = amplitudeToDb((mode == RMS) ? std::sqrt(v) : v);
-		if (db > dbMax)
+		if (db >= dbMax)
 			return 1.f;
-		else if (db < dbMin)
+		else if (db <= dbMin)
 			return 0.f;
 		else
 			return math::rescale(db, dbMin, dbMax, 0.f, 1.f);