Added DaisySP

daisysp/Synthesis/formantosc.cpp

@@ -0,0 +1,96 @@
+#include "dsp.h"
+#include "formantosc.h"
+#include <math.h>
+
+using namespace daisysp;
+
+void FormantOscillator::Init(float sample_rate)
+{
+    carrier_phase_ = 0.0f;
+    formant_phase_ = 0.0f;
+    next_sample_   = 0.0f;
+
+    carrier_frequency_ = 0.0f;
+    formant_frequency_ = 100.f;
+    phase_shift_       = 0.0f;
+
+    sample_rate_ = sample_rate;
+}
+
+float FormantOscillator::Process()
+{
+    float this_sample = next_sample_;
+    float next_sample = 0.0f;
+    carrier_phase_ += carrier_frequency_;
+
+    if(carrier_phase_ >= 1.0f)
+    {
+        carrier_phase_ -= 1.0f;
+        float reset_time = carrier_phase_ / carrier_frequency_;
+
+        float formant_phase_at_reset
+            = formant_phase_ + (1.0f - reset_time) * formant_frequency_;
+        float before        = Sine(formant_phase_at_reset + phase_shift_
+                            + (ps_inc_ * (1.0f - reset_time)));
+        float after         = Sine(0.0f + phase_shift_ + ps_inc_);
+        float discontinuity = after - before;
+        this_sample += discontinuity * ThisBlepSample(reset_time);
+        next_sample += discontinuity * NextBlepSample(reset_time);
+        formant_phase_ = reset_time * formant_frequency_;
+    }
+    else
+    {
+        formant_phase_ += formant_frequency_;
+        if(formant_phase_ >= 1.0f)
+        {
+            formant_phase_ -= 1.0f;
+        }
+    }
+
+    phase_shift_ += ps_inc_;
+    ps_inc_ = 0.f;
+
+    next_sample += Sine(formant_phase_ + phase_shift_);
+
+    next_sample_ = next_sample;
+    return this_sample;
+}
+
+void FormantOscillator::SetFormantFreq(float freq)
+{
+    //convert from Hz to phase_inc / sample
+    formant_frequency_ = freq / sample_rate_;
+    formant_frequency_ = formant_frequency_ >= .25f ? .25f : formant_frequency_;
+    formant_frequency_
+        = formant_frequency_ <= -.25f ? -.25f : formant_frequency_;
+}
+
+void FormantOscillator::SetCarrierFreq(float freq)
+{
+    //convert from Hz to phase_inc / sample
+    carrier_frequency_ = freq / sample_rate_;
+    carrier_frequency_ = carrier_frequency_ >= .25f ? .25f : carrier_frequency_;
+    carrier_frequency_
+        = carrier_frequency_ <= -.25f ? -.25f : carrier_frequency_;
+}
+
+void FormantOscillator::SetPhaseShift(float ps)
+{
+    ps_inc_ = ps - phase_shift_;
+}
+
+inline float FormantOscillator::Sine(float phase)
+{
+    return sinf(phase * TWOPI_F);
+}
+
+inline float FormantOscillator::ThisBlepSample(float t)
+{
+    return 0.5f * t * t;
+}
+
+inline float FormantOscillator::NextBlepSample(float t)
+{
+    t = 1.0f - t;
+    return -0.5f * t * t;
+}