BogaudioModules

commit 407a5484cdfccaec0fbfbb3b67214904abdb062c
parent aeddb9f698094d2be9a39bd561408dd3a62825e6
Author: Matt Demanett <matt@demanett.net>
Date:   Wed,  7 Mar 2018 22:38:03 -0500

Add wavetable sine oscillator; use it in 8FO.

Diffstat:
M
src/EightFO.cpp
 | 
2
+-
M
src/EightFO.hpp
 | 
2
++
M
src/Test.cpp
 | 
2
+-
M
src/Test.hpp
 | 
9
++++++---
M
src/dsp/oscillator.cpp
 | 
34
++++++++++++++++++++++++++++++++++
M
src/dsp/oscillator.hpp
 | 
44
++++++++++++++++++++++++++++++++++++++++++++

6 files changed, 88 insertions(+), 5 deletions(-)
diff --git a/src/EightFO.cpp b/src/EightFO.cpp
@@ -116,7 +116,7 @@ void EightFO::updateOutput(bool useSample, Output& output, float& offset, float&
 					assert(false);
 				}
 				case SINE_WAVE: {
-					v = sinf((_phasor._phase + offset) * M_PI); // FIXME
+					v = _sine.nextFromPhasor(_phasor, offset);
 					break;
 				}
 				case TRIANGLE_WAVE: {
diff --git a/src/EightFO.hpp b/src/EightFO.hpp
@@ -95,6 +95,7 @@ struct EightFO : Module {
 	SchmittTrigger _resetTrigger;
 
 	Phasor _phasor;
+	SineTableOscillator _sine;
 	TriangleOscillator _triangle;
 	SawOscillator _ramp;
 	SquareOscillator _square;
@@ -129,6 +130,7 @@ struct EightFO : Module {
 	EightFO()
 	: Module(NUM_PARAMS, NUM_INPUTS, NUM_OUTPUTS, NUM_LIGHTS)
 	, _phasor(engineGetSampleRate(), 1.0f)
+	, _sine(0.0f, 0.0f)
 	, _triangle(0.0f, 0.0f)
 	, _ramp(0.0f, 0.0f)
 	, _square(0.0f, 0.0f)
diff --git a/src/Test.cpp b/src/Test.cpp
@@ -37,7 +37,7 @@ void Test::step() {
 
 	_sine2.setSampleRate(engineGetSampleRate());
 	_sine2.setFrequency(oscillatorPitch());
-	outputs[OUT2_OUTPUT].value = 5.0f * powf(_sine2.next(), 5.0f);
+	outputs[OUT2_OUTPUT].value = _sine2.next();
 
 #elif SQUARE
 	_square.setSampleRate(engineGetSampleRate());
diff --git a/src/Test.hpp b/src/Test.hpp
@@ -74,7 +74,7 @@ struct Test : Module {
 	LowPassFilter _lpf;
 #elif SINE
 	SineOscillator _sine;
-	SineOscillator _sine2;
+	SineTableOscillator _sine2;
 #elif SQUARE
 	SquareOscillator _square;
 #elif SAW
@@ -99,7 +99,7 @@ struct Test : Module {
 	, _lpf(44100.0, 1000.0, 1.0)
 #elif SINE
 	, _sine(44100.0, 1000.0, 5.0)
-	, _sine2(44100.0, 1000.0, 1.0, M_PI/1.0f)
+	, _sine2(44100.0, 1000.0, 5.0)
 #elif SQUARE
 	, _square(44100.0, 1000.0, 5.0)
 #elif SAW
@@ -117,7 +117,10 @@ struct Test : Module {
 	{
 		onReset();
 
-#ifdef SINEBANK
+#ifdef SINE
+		_sine2.setPhase(M_PI);
+
+#elif SINEBANK
 		const float baseAmplitude = 5.0;
 		switch (5) {
 			case 1: {
diff --git a/src/dsp/oscillator.cpp b/src/dsp/oscillator.cpp
@@ -39,6 +39,32 @@ float Phasor::_nextForPhase(float phase) {
 }
 
 
+void TablePhasor::generate() {
+	if (!_table) {
+		_table = new float[_length] {};
+		_generate();
+	}
+}
+
+float TablePhasor::_nextForPhase(float phase) {
+	if (!_table) {
+		generate();
+	}
+
+	while (phase >= maxPhase) {
+		phase -= maxPhase;
+	}
+	while (phase < 0.0f) {
+		phase += maxPhase;
+	}
+	float fi = phase * (_length / 2);
+	int i = (int)fi;
+	float v1 = _table[i];
+	float v2 = _table[i + 1 == _length ? 0 : i + 1];
+	return _amplitude * (v1 + (fi - i)*(v2 - v1));
+}
+
+
 // A New Recursive Quadrature Oscillator, Martin Vicanek, 2015 - http://vicanek.de/articles/QuadOsc.pdf
 void SineOscillator::setPhase(double phase) {
 	_x = cos(phase);
@@ -59,6 +85,14 @@ float SineOscillator::_next() {
 }
 
 
+void SineTableOscillator::_generate() {
+	const float twoPI = 2.0f * M_PI;
+	for (int i = 0; i < _length; ++i) {
+		_table[i] = sinf(twoPI * (i / (float)_length));
+	}
+}
+
+
 float SawOscillator::_nextForPhase(float phase) {
 	return _amplitude * (phase - halfMaxPhase);
 }
diff --git a/src/dsp/oscillator.hpp b/src/dsp/oscillator.hpp
@@ -2,6 +2,7 @@
 
 #include <stdlib.h>
 #include <stdint.h>
+#include <assert.h>
 #include <vector>
 
 #include "base.hpp"
@@ -77,6 +78,36 @@ struct Phasor : OscillatorGenerator {
 	static float phaseToRadians(float phase) { return phase * M_PI; }
 };
 
+struct TablePhasor : Phasor {
+	int _length = 0;
+	float* _table = NULL;
+	float _amplitude;
+
+	TablePhasor(
+		double sampleRate,
+		double frequency,
+		float amplitude = 1.0f,
+		int n = 10
+	)
+	: Phasor(sampleRate, frequency)
+	, _amplitude(amplitude)
+	{
+		assert(n > 0);
+		assert(n <= 16);
+		_length = 1 << n;
+	}
+	virtual ~TablePhasor() {
+		if (_table) {
+			delete[] _table;
+		}
+	}
+
+	void generate();
+	virtual void _generate() = 0;
+
+	virtual float _nextForPhase(float phase) override;
+};
+
 struct SineOscillator : OscillatorGenerator {
 	double _k1, _k2;
 	double _x;
@@ -109,6 +140,19 @@ struct SineOscillator : OscillatorGenerator {
 	virtual float _next() override;
 };
 
+struct SineTableOscillator : TablePhasor {
+	SineTableOscillator(
+		float sampleRate,
+		float frequency,
+		float amplitude = 1.0
+	)
+	: TablePhasor(sampleRate, frequency, amplitude)
+	{
+	}
+
+	virtual void _generate() override;
+};
+
 struct SawOscillator : Phasor {
 	const float halfMaxPhase = 0.5f * maxPhase;
 	float _amplitude;