Added DaisySP

daisysp/Effects/flanger.cpp

@@ -0,0 +1,83 @@
+#include "dsp.h"
+#include "flanger.h"
+#include <math.h>
+
+using namespace daisysp;
+
+void Flanger::Init(float sample_rate)
+{
+    sample_rate_ = sample_rate;
+
+    SetFeedback(.2f);
+
+    del_.Init();
+    lfo_amp_ = 0.f;
+    SetDelay(.75);
+
+    lfo_phase_ = 0.f;
+    SetLfoFreq(.3);
+    SetLfoDepth(.9);
+}
+
+float Flanger::Process(float in)
+{
+    float lfo_sig = ProcessLfo();
+    del_.SetDelay(1.f + lfo_sig + delay_);
+
+    float out = del_.Read();
+    del_.Write(in + out * feedback_);
+
+    return (in + out) * .5f; //equal mix
+}
+
+void Flanger::SetFeedback(float feedback)
+{
+    feedback_ = fclamp(feedback, 0.f, 1.f);
+    feedback_ *= .97f;
+}
+
+void Flanger::SetLfoDepth(float depth)
+{
+    depth    = fclamp(depth, 0.f, .93f);
+    lfo_amp_ = depth * delay_;
+}
+
+void Flanger::SetLfoFreq(float freq)
+{
+    freq = 4.f * freq / sample_rate_;
+    freq *= lfo_freq_ < 0.f ? -1.f : 1.f;  //if we're headed down, keep going
+    lfo_freq_ = fclamp(freq, -.25f, .25f); //clip at +/- .125 * sr
+}
+
+void Flanger::SetDelay(float delay)
+{
+    delay = (.1f + delay * 6.9); //.1 to 7 ms
+    SetDelayMs(delay);
+}
+
+void Flanger::SetDelayMs(float ms)
+{
+    ms     = fmax(.1, ms);
+    delay_ = ms * .001f * sample_rate_; //ms to samples
+
+    lfo_amp_ = fmin(lfo_amp_, delay_); //clip this if needed
+}
+
+float Flanger::ProcessLfo()
+{
+    lfo_phase_ += lfo_freq_;
+
+    //wrap around and flip direction
+    if(lfo_phase_ > 1.f)
+    {
+        lfo_phase_ = 1.f - (lfo_phase_ - 1.f);
+        lfo_freq_ *= -1.f;
+    }
+    else if(lfo_phase_ < -1.f)
+    {
+        lfo_phase_ = -1.f - (lfo_phase_ + 1.f);
+        lfo_freq_ *= -1.f;
+    }
+
+    return lfo_phase_ * lfo_amp_;
+}