Fix popping on increase of polyphony channels (EvenVCO)

Fixes VCVRack#33

CHANGELOG.md

@@ -4,7 +4,8 @@
   * Added Noise Plethora
   * Chopping Kinky upgraded to use improved DC blocker
   * Added bypass for Spring Reverb
-  * Minor fix for Kickall trigger
+  * Bugfix: Kickall trigger input and button can now work independently
+  * Bugfix: remove pop on number of polyphony engines change
 
 ## v2.0.0
   * update to Rack 2 API (added tooltips, bypass, removed boilerplate etc)

src/EvenVCO.cpp

@@ -120,8 +120,10 @@ struct EvenVCO : Module {
 			phase[c / 4] += deltaPhase[c / 4];
 		}
 
-		// the next block can't be done with SIMD instructions:
-		for (int c = 0; c < channels; c++) {
+		// the next block can't be done with SIMD instructions, but should at least be completed with
+		// blocks of 4 (otherwise popping artfifacts are generated from invalid phase/oldPhase/deltaPhase)
+		int channelsRoundedUpNearestFour = std::ceil(channels / 4.f) * 4;
+		for (int c = 0; c < channelsRoundedUpNearestFour; c++) {
 
 			if (oldPhase[c / 4].s[c % 4] < 0.5 && phase[c / 4].s[c % 4] >= 0.5) {
 				float crossing = -(phase[c / 4].s[c % 4] - 0.5) / deltaPhase[c / 4].s[c % 4];
@@ -161,20 +163,13 @@ struct EvenVCO : Module {
 		float_4 square[4] = {};
 		float_4 triOut[4] = {};
 
-		for (int c = 0; c < channels; c++) {
+		for (int c = 0; c < channelsRoundedUpNearestFour; c++) {
 			triSquareMinBlepOut[c / 4].s[c % 4] = triSquareMinBlep[c].process();
 			doubleSawMinBlepOut[c / 4].s[c % 4] = doubleSawMinBlep[c].process();
 			sawMinBlepOut[c / 4].s[c % 4] = sawMinBlep[c].process();
 			squareMinBlepOut[c / 4].s[c % 4] = squareMinBlep[c].process();
 		}
 
-		// Outputs
-		outputs[TRI_OUTPUT].setChannels(channels);
-		outputs[SINE_OUTPUT].setChannels(channels);
-		outputs[EVEN_OUTPUT].setChannels(channels);
-		outputs[SAW_OUTPUT].setChannels(channels);
-		outputs[SQUARE_OUTPUT].setChannels(channels);
-
 		for (int c = 0; c < channels; c += 4) {
 
 			triSquare[c / 4] = simd::ifelse((phase[c / 4] < 0.5f), -1.f, +1.f);
@@ -208,6 +203,13 @@ struct EvenVCO : Module {
 			outputs[SAW_OUTPUT].setVoltageSimd(saw[c / 4], c);
 			outputs[SQUARE_OUTPUT].setVoltageSimd(square[c / 4], c);
 		}
+
+		// Outputs
+		outputs[TRI_OUTPUT].setChannels(channels);
+		outputs[SINE_OUTPUT].setChannels(channels);
+		outputs[EVEN_OUTPUT].setChannels(channels);
+		outputs[SAW_OUTPUT].setChannels(channels);
+		outputs[SQUARE_OUTPUT].setChannels(channels);
 	}
 };