[kyma] Add basic oscillator

src/kyma/main.cpp

@@ -1,19 +1,30 @@
+#include "mc/dsp/oscillator.hpp"
+
 #include "daisy_patch_sm.h"
 
-daisy::patch_sm::DaisyPatchSM patch;
+auto oscillator = mc::Oscillator<float>{};
+auto patch      = daisy::patch_sm::DaisyPatchSM{};
 
-void AudioCallback(daisy::AudioHandle::InputBuffer in, daisy::AudioHandle::OutputBuffer out, size_t size)
+static auto process(daisy::AudioHandle::InputBuffer /*in*/, daisy::AudioHandle::OutputBuffer out, size_t size) -> void
 {
-    for (size_t i = 0; i < size; i++)
+    auto* leftOut  = out[0];
+    auto* rightOut = out[0];
+
+    for (size_t i = 0; i < size; ++i)
     {
-        out[0][i] = in[0][i];
-        out[1][i] = in[1][i];
+        auto const sample = oscillator();
+        leftOut[i]        = sample;
+        rightOut[i]       = sample;
     }
 }
 
 int main(void)
 {
+    oscillator.setShape(mc::OscillatorShape::Sine);
+    oscillator.setFrequency(440.0F);
+    oscillator.setSampleRate(patch.AudioSampleRate());
+
     patch.Init();
-    patch.StartAudio(AudioCallback);
+    patch.StartAudio(process);
     while (true) {}
 }

src/kyma/mc/dsp/constants.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+namespace mc::numbers
+{
+
+template<typename FloatType>
+constexpr auto pi = static_cast<FloatType>(3.141592653589793);
+
+template<typename FloatType>
+constexpr auto twoPi = pi<FloatType> * static_cast<FloatType>(2);
+
+}  // namespace mc::numbers

src/kyma/mc/dsp/oscillator.hpp

@@ -0,0 +1,119 @@
+#pragma once
+
+#include "constants.hpp"
+
+namespace mc
+{
+
+enum struct OscillatorShape
+{
+    Sine,
+    Triangle,
+    Saw,
+    Square,
+};
+
+template<typename SampleType>
+struct Oscillator
+{
+    Oscillator() = default;
+
+    auto setShape(OscillatorShape shape) noexcept -> void;
+    auto setPhase(SampleType phase) noexcept -> void;
+    auto setFrequency(SampleType frequency) noexcept -> void;
+    auto setSampleRate(SampleType sampleRate) noexcept -> void;
+
+    [[nodiscard]] auto operator()() noexcept -> SampleType;
+
+private:
+    [[nodiscard]] auto sine() noexcept -> SampleType;
+    [[nodiscard]] auto triangle() noexcept -> SampleType;
+    [[nodiscard]] auto saw() noexcept -> SampleType;
+    [[nodiscard]] auto pulse(SampleType puslseWidth) noexcept -> SampleType;
+
+    OscillatorShape _shape{};
+    SampleType _phase{0};
+    SampleType _frequency{0};
+    SampleType _puslseWidth{0.5};
+    SampleType _sampleRate{0};
+};
+
+template<typename SampleType>
+auto Oscillator<SampleType>::setShape(OscillatorShape shape) noexcept -> void
+{
+    _shape = shape;
+}
+
+template<typename SampleType>
+auto Oscillator<SampleType>::setPhase(SampleType phase) noexcept -> void
+{
+    _phase = phase;
+}
+
+template<typename SampleType>
+auto Oscillator<SampleType>::setFrequency(SampleType frequency) noexcept -> void
+{
+    _frequency = frequency;
+}
+
+template<typename SampleType>
+auto Oscillator<SampleType>::setSampleRate(SampleType sampleRate) noexcept -> void
+{
+    _sampleRate = sampleRate;
+}
+
+template<typename SampleType>
+auto Oscillator<SampleType>::operator()() noexcept -> SampleType
+{
+    if (_shape == OscillatorShape::Sine) { return sine(); }
+    if (_shape == OscillatorShape::Triangle) { return triangle(); }
+    if (_shape == OscillatorShape::Saw) { return saw(); }
+    if (_shape == OscillatorShape::Square) { return pulse(_puslseWidth); }
+    return 0.0F;
+}
+
+template<typename SampleType>
+auto Oscillator<SampleType>::sine() noexcept -> SampleType
+{
+    auto output = std::sin(_phase * numbers::twoPi<SampleType>);
+
+    _phase += 1.0F / (_sampleRate / _frequency);
+    _phase -= std::floor(_phase);
+
+    return output;
+}
+
+template<typename SampleType>
+auto Oscillator<SampleType>::pulse(SampleType puslseWidth) noexcept -> SampleType
+{
+    if (puslseWidth < 0.0F) { puslseWidth = 0.0F; }
+    if (puslseWidth > 1.0F) { puslseWidth = 1; }
+
+    if (_phase >= 1.0F) { _phase -= 1.0F; }
+    _phase += (1.0F / (_sampleRate / (_frequency)));
+
+    if (_phase < puslseWidth) { return SampleType{-1}; }
+    return 1.0F;
+}
+
+template<typename SampleType>
+auto Oscillator<SampleType>::saw() noexcept -> SampleType
+{
+    auto output = _phase;
+
+    if (_phase >= 1.0F) { _phase -= SampleType{2}; }
+    _phase += (1.0F / (_sampleRate / (_frequency))) * SampleType{2};
+
+    return output;
+}
+
+template<typename SampleType>
+auto Oscillator<SampleType>::triangle() noexcept -> SampleType
+{
+    if (_phase >= 1.0F) { _phase -= 1.0F; }
+    _phase += (1.0F / (_sampleRate / (_frequency)));
+    if (_phase <= SampleType{0.5}) { return (_phase - SampleType{0.25}) * SampleType{4}; }
+    return ((1.0F - _phase) - SampleType{0.25}) * SampleType{4};
+}
+
+}  // namespace mc