BogaudioModules

commit 2aeb0c15671fad693e43ec88e1722d0d34e140d7
parent 4c9d6c319b0b27dfbd7c2163938f333eb9a43d39
Author: Matt Demanett <matt@demanett.net>
Date:   Thu, 18 Jan 2018 00:19:37 -0500

Add functions for pitch calculations in dsp lib; refactor Reftone to use them; implement Detune.

Diffstat:
M
src/Detune.cpp
 | 
52
++++++++++++++++++++++++++++++++++++++++++++++------
M
src/Reftone.cpp
 | 
12
++++++------
A
src/dsp/pitch.hpp
 | 
36
++++++++++++++++++++++++++++++++++++

3 files changed, 88 insertions(+), 12 deletions(-)
diff --git a/src/Detune.cpp b/src/Detune.cpp
@@ -1,5 +1,8 @@
 
 #include "bogaudio.hpp"
+#include "dsp/pitch.hpp"
+
+using namespace bogaudio::dsp;
 
 struct Detune : Module {
 	enum ParamsIds {
@@ -31,15 +34,52 @@ struct Detune : Module {
 		reset();
 	}
 
-	virtual void reset() override;
 	virtual void step() override;
 };
 
-void Detune::reset() {
-}
-
 void Detune::step() {
-	lights[QUANTIZE_LIGHT].value = params[QUANTIZE_PARAM].value == 1.0;
+	if (!(outputs[OUT_PLUS_OUTPUT].active || outputs[OUT_MINUS_OUTPUT].active || outputs[THRU_OUTPUT].active)) {
+		return;
+	}
+
+	float cents = params[CENTS_PARAM].value;
+	if (inputs[CV_INPUT].active) {
+		cents *= clampf(inputs[CV_INPUT].value, 0.0, 10.0) / 10.0;
+	}
+	if (params[QUANTIZE_PARAM].value > 0.5) {
+		cents = roundf(cents);
+	}
+	cents /= 100.0;
+
+	if (inputs[IN_INPUT].active) {
+		float cv = inputs[IN_INPUT].value;
+		outputs[THRU_OUTPUT].value = cv;
+		if (cents < 0.001) {
+			outputs[OUT_PLUS_OUTPUT].value = cv;
+			outputs[OUT_MINUS_OUTPUT].value = cv;
+		}
+		else {
+			float semitone = cvToSemitone(cv);
+			outputs[OUT_PLUS_OUTPUT].value = semitoneToCV(semitone + cents);
+			outputs[OUT_MINUS_OUTPUT].value = semitoneToCV(semitone - cents);
+		}
+	}
+	else {
+		const float frequency = 440.0;
+		const float cv = frequencyToCV(frequency);
+		const float semitone = frequencyToSemitone(frequency);
+		outputs[THRU_OUTPUT].value = cv;
+		if (cents < 0.001) {
+			outputs[OUT_PLUS_OUTPUT].value = cv;
+			outputs[OUT_MINUS_OUTPUT].value = cv;
+		}
+		else {
+			outputs[OUT_PLUS_OUTPUT].value = semitoneToCV(semitone + cents);
+			outputs[OUT_MINUS_OUTPUT].value = semitoneToCV(semitone - cents);
+		}
+	}
+
+	lights[QUANTIZE_LIGHT].value = params[QUANTIZE_PARAM].value > 0.5;
 }
 
 
@@ -74,7 +114,7 @@ DetuneWidget::DetuneWidget() {
 	// end generated by svg_widgets.rb
 
 	{
-		auto w = createParam<Knob26>(centsParamPosition, module, Detune::CENTS_PARAM, 0.0, 10.0, 0.0);
+		auto w = createParam<Knob26>(centsParamPosition, module, Detune::CENTS_PARAM, 0.0, 50.0, 0.0);
 		dynamic_cast<Knob*>(w)->snap = true;
 		addParam(w);
 	}
diff --git a/src/Reftone.cpp b/src/Reftone.cpp
@@ -1,6 +1,7 @@
 
 #include "bogaudio.hpp"
 #include "dsp/oscillator.hpp"
+#include "dsp/pitch.hpp"
 
 using namespace bogaudio::dsp;
 
@@ -46,18 +47,17 @@ struct Reftone : Module {
 };
 
 void Reftone::step() {
-	const float f0 = 261.626;
-	const int f0Pitch = 0;
-	const int f0Octave = 4;
-	const float twelfthRootTwo = 1.0594630943592953;
+	// C4 -- the pitch.hpp reference frequency -- in knob values:
+	const int referencePitch = 0;
+	const int referenceOctave = 4;
 
 	_pitch = clampf(params[PITCH_PARAM].value, 0.0, 11.0);
 	_octave = clampf(params[OCTAVE_PARAM].value, 1.0, 8.0);
 	_fine = clampf(params[FINE_PARAM].value, -0.99, 0.99);
-	_frequency = f0*powf(twelfthRootTwo, 12*(_octave - f0Octave) + (_pitch - f0Pitch) + _fine);
+	_frequency = semitoneToFrequency(referenceSemitone + 12*(_octave - referenceOctave) + (_pitch - referencePitch) + _fine);
 
 	if (outputs[CV_OUTPUT].active) {
-		outputs[CV_OUTPUT].value = log2f(_frequency / f0);
+		outputs[CV_OUTPUT].value = frequencyToCV(_frequency);
 	}
 	else {
 		outputs[CV_OUTPUT].value = 0.0;
diff --git a/src/dsp/pitch.hpp b/src/dsp/pitch.hpp
@@ -0,0 +1,36 @@
+#pragma once
+
+namespace bogaudio {
+namespace dsp {
+
+const float referenceFrequency = 261.626; // C4; frequency at which Rack 1v/octave CVs are zero.
+const float referenceSemitone = 60.0; // C4; value of C4 in semitones is arbitrary here, so have it match midi note numbers when rounded to integer.
+const float twelfthRootTwo = 1.0594630943592953;
+const float logTwelfthRootTwo = logf(1.0594630943592953);
+
+inline float frequencyToSemitone(float frequency) {
+	return logf(frequency / referenceFrequency) / logTwelfthRootTwo + referenceSemitone;
+}
+
+inline float semitoneToFrequency(float semitone) {
+	return powf(twelfthRootTwo, semitone - referenceSemitone) * referenceFrequency;
+}
+
+inline float frequencyToCV(float frequency) {
+	return log2f(frequency / referenceFrequency);
+}
+
+inline float cvToFrequency(float cv) {
+	return powf(2.0, cv) * referenceFrequency;
+}
+
+inline float cvToSemitone(float cv) {
+	return frequencyToSemitone(cvToFrequency(cv));
+}
+
+inline float semitoneToCV(float semitone) {
+	return frequencyToCV(semitoneToFrequency(semitone));
+}
+
+} // namespace dsp
+} // namespace bogaudio