84 lines
2.1 KiB
C++
84 lines
2.1 KiB
C++
#include "dsp.h"
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#include "oscillator.h"
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using namespace daisysp;
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static inline float Polyblep(float phase_inc, float t);
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float Oscillator::Process()
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{
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float out, t;
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switch(waveform_)
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{
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case WAVE_SIN: out = sinf(phase_ * TWOPI_F); break;
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case WAVE_TRI:
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t = -1.0f + (2.0f * phase_);
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out = 2.0f * (fabsf(t) - 0.5f);
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break;
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case WAVE_SAW: out = -1.0f * (((phase_ * 2.0f)) - 1.0f); break;
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case WAVE_RAMP: out = ((phase_ * 2.0f)) - 1.0f; break;
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case WAVE_SQUARE: out = phase_ < pw_ ? (1.0f) : -1.0f; break;
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case WAVE_POLYBLEP_TRI:
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t = phase_;
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out = phase_ < 0.5f ? 1.0f : -1.0f;
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out += Polyblep(phase_inc_, t);
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out -= Polyblep(phase_inc_, fastmod1f(t + 0.5f));
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// Leaky Integrator:
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// y[n] = A + x[n] + (1 - A) * y[n-1]
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out = phase_inc_ * out + (1.0f - phase_inc_) * last_out_;
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last_out_ = out;
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out *= 4.f; // normalize amplitude after leaky integration
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break;
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case WAVE_POLYBLEP_SAW:
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t = phase_;
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out = (2.0f * t) - 1.0f;
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out -= Polyblep(phase_inc_, t);
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out *= -1.0f;
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break;
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case WAVE_POLYBLEP_SQUARE:
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t = phase_;
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out = phase_ < pw_ ? 1.0f : -1.0f;
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out += Polyblep(phase_inc_, t);
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out -= Polyblep(phase_inc_, fastmod1f(t + (1.0f - pw_)));
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out *= 0.707f; // ?
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break;
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default: out = 0.0f; break;
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}
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phase_ += phase_inc_;
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if(phase_ > 1.0f)
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{
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phase_ -= 1.0f;
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eoc_ = true;
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}
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else
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{
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eoc_ = false;
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}
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eor_ = (phase_ - phase_inc_ < 0.5f && phase_ >= 0.5f);
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return out * amp_;
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}
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float Oscillator::CalcPhaseInc(float f)
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{
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return f * sr_recip_;
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}
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static float Polyblep(float phase_inc, float t)
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{
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float dt = phase_inc;
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if(t < dt)
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{
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t /= dt;
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return t + t - t * t - 1.0f;
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}
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else if(t > 1.0f - dt)
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{
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t = (t - 1.0f) / dt;
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return t * t + t + t + 1.0f;
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}
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else
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{
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return 0.0f;
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}
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}
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