Add wavetable oscillator

CMakeLists.txt

@@ -58,6 +58,7 @@ Source/Utility/dcblock.cpp
 Source/Utility/jitter.cpp
 Source/Utility/metro.cpp
 Source/Utility/port.cpp
+Source/Utility/wavetables.cpp
 )
 
 

Makefile

@@ -93,7 +93,8 @@ UTILITY_MODULES = \
 dcblock \
 jitter \
 metro \
-port 
+port \
+wavetables
 #delayline 
 #dsp 
 #looper

Source/Synthesis/wavetable_osc.h

@@ -0,0 +1,141 @@
+#pragma once
+#ifndef DSY_WAVETABLEOSC_H
+#define DSY_WAVETABLEOSC_H
+
+#include "Utility/wavetables.h"
+
+
+namespace daisysp
+{
+/**
+ * @brief Wave table oscillator
+ *
+ * Based on implementation from STK (by Perry R. Cook and Gary P. Scavone, 1995--2021)
+ */
+class WavetableOsc
+{
+  public:
+    enum Waveform
+    {
+        WAVE_SIN,
+        WAVE_TRI,
+        WAVE_SAW,
+        WAVE_SQUARE,
+        WAVE_LAST,
+    };
+
+    void Init(float sample_rate_)
+    {
+        sample_rate   = sample_rate_;
+        sr_resiprocal = 1 / sample_rate;
+        SetWaveform(WAVE_SQUARE);
+        SetFreq(440);
+        SetAmp(0.7f);
+    }
+
+    void SetWaveform(const Waveform wf)
+    {
+        switch(wf)
+        {
+            case Waveform::WAVE_SIN: SetWaveTable(&Tables::Sine); break;
+            case Waveform::WAVE_TRI: SetWaveTable(&Tables::Tri); break;
+            case Waveform::WAVE_SAW: SetWaveTable(&Tables::Saw); break;
+            case Waveform::WAVE_SQUARE: SetWaveTable(&Tables::Square); break;
+            default: SetWaveTable(&Tables::Sine);
+        }
+    }
+
+    void SetWaveTable(WaveTable *table)
+    {
+        m_table    = table;
+        table_size = m_table->buff->wt_size;
+    }
+
+    /**
+     * @brief  Set the data interpolation rate based on a looping frequency.
+     * 
+     * This function determines the interpolation rate based on the file
+     * size and the current Stk::sampleRate.  The \e frequency value
+     * corresponds to file cycles per second.  The frequency can be
+     * negative, in which case the loop is read in reverse order.
+     * 
+     * @param frequency Osc frequency in Hz.
+     */
+    void SetFreq(float frequency)
+    {
+        auto norm_freq = frequency * sr_resiprocal;
+        this->SetRate(table_size * norm_freq);
+
+        // update the current wave table selector
+        m_table->SetTopFreq(norm_freq);
+    }
+
+    /**
+     * @brief Add a phase offset in cycles, where 1.0 = fileSize.
+     * 
+     * 
+     * This function determines a time offset based on the file
+     * size and the current sample sate.  The \e angle value
+     * is a multiple of file size.
+     * 
+     * @param angle Phase offset in cycles.
+     */
+    void PhaseAdd(float angle)
+    {
+        time_ += table_size * angle;
+
+        if(time_ < 0.0f)
+            time_ += table_size;
+        else if(time_ >= table_size)
+            time_ -= table_size;
+    }
+
+    void SetAmp(const float a) { amp = a; }
+
+    /**
+     * @brief Compute a sample frame and return the value.
+     */
+    float Process()
+    {
+        while(time_ < 0.0f)
+            time_ += table_size;
+        while(time_ >= table_size)
+            time_ -= table_size;
+
+        float out = m_table->GetSample(time_);
+
+        time_ += rate_;
+
+        return out * amp;
+    }
+
+  private:
+    /**
+    * @brief Set the data read rate in samples.  The rate can be negative.
+    * 
+    * If the rate value is negative, the data is read in reverse order.
+    * 
+    * @param rate 
+    */
+    void SetRate(float rate)
+    {
+        rate_ = rate;
+
+        if(std::fmod(rate_, 1.0f) != 0.0f)
+            interpolate_ = true;
+        else
+            interpolate_ = false;
+    }
+
+    WaveTable *m_table;
+    float      sample_rate;
+    float      sr_resiprocal;
+    float      time_        = 0.f;
+    bool       interpolate_ = false;
+    float      rate_;
+    float      amp        = 1;
+    uint16_t   table_size = 1;
+};
+
+} // namespace daisysp
+#endif

Source/Utility/wavetables.cpp

@@ -0,0 +1,27 @@
+#include "wavetables.h"
+
+// hackish way to make it work for both mcu and computer
+#ifndef DSY_SDRAM_BSS
+#define DSY_SDRAM_BSS /* emtpy */
+#endif
+
+namespace daisysp
+{
+template <typename T, FFTFunction<T> fft>
+bool Tables<T, fft>::generated = false;
+
+template <typename T, FFTFunction<T> fft>
+WaveBuffer DSY_SDRAM_BSS Tables<T, fft>::buffer_pool[40];
+template <typename T, FFTFunction<T> fft>
+uint8_t Tables<T, fft>::num_buffers = 0;
+
+template <typename T, FFTFunction<T> fft>
+WaveTable Tables<T, fft>::Sine;
+template <typename T, FFTFunction<T> fft>
+WaveTable Tables<T, fft>::Square;
+template <typename T, FFTFunction<T> fft>
+WaveTable Tables<T, fft>::Tri;
+template <typename T, FFTFunction<T> fft>
+WaveTable Tables<T, fft>::Saw;
+
+} // namespace daisysp