Set plug lights to 0 when disconnected

src/engine/Engine.cpp

@@ -117,7 +117,7 @@ static void Engine_step(Engine *engine) {
 		}
 	}
 
-	float cpuLambda = engine->internal->sampleTime / 2.f;
+	const float cpuLambda = engine->internal->sampleTime / 2.f;
 
 	// Iterate modules
 	int modulesLen = engine->modules.size();

src/engine/Port.cpp

@@ -6,12 +6,12 @@ namespace rack {
 
 void Port::step() {
 	// Set plug lights
-	if (channels == 0) {
+	if (!isConnected() || getChannels() == 0) {
 		plugLights[0].setBrightness(0.f);
 		plugLights[1].setBrightness(0.f);
 		plugLights[2].setBrightness(0.f);
 	}
-	else if (channels == 1) {
+	else if (getChannels() == 1) {
 		float v = getVoltage() / 10.f;
 		plugLights[0].setBrightnessSmooth(v);
 		plugLights[1].setBrightnessSmooth(-v);
@@ -19,7 +19,7 @@ void Port::step() {
 	}
 	else {
 		float v2 = 0.f;
-		for (int c = 0; c < channels; c++) {
+		for (int c = 0; c < getChannels(); c++) {
 			v2 += std::pow(getVoltage(c), 2);
 		}
 		float v = std::sqrt(v2) / 10.f;