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#include "SC_PlugIn.h"
static InterfaceTable *ft;
struct SawDPW : public Unit
{
double mPhase; // phase of the oscillator, from -1 to 1.
float mFreqMul; // a constant for multiplying frequency
float mVal; // memory of prev value
float mFreq; // memory of prev freq, just for recalculating scalefac
float mScalefac;
};
extern "C"
{
void load(InterfaceTable *inTable);
void SawDPW_next_a(SawDPW *unit, int inNumSamples);
void SawDPW_next_k(SawDPW *unit, int inNumSamples);
void SawDPW_Ctor(SawDPW* unit);
};
void SawDPW_Ctor(SawDPW* unit)
{
if (INRATE(0) == calc_FullRate) {
SETCALC(SawDPW_next_a);
} else {
SETCALC(SawDPW_next_k);
}
unit->mFreqMul = 2.0 * SAMPLEDUR;
unit->mVal = 0.f;
unit->mFreq = 0.f;
unit->mScalefac = 0.f;
// get initial phase of oscillator
unit->mPhase = IN0(1);
SawDPW_next_a(unit, 1);
}
void SawDPW_next_a(SawDPW *unit, int inNumSamples)
{
float *out = OUT(0);
float *freq = IN(0);
float freqmul = unit->mFreqMul;
float val = unit->mVal;
double phase = unit->mPhase;
float oldval;
float prevfreq = unit->mFreq;
float scalefac = unit->mScalefac;
for (int i=0; i < inNumSamples; ++i)
{
// The "phase" is our modulo counter, -1 to 1
phase += (*freq) * freqmul;
if(phase >= 1.) phase -= 2.;
if(phase < -1.) phase += 2.;
// Square the phase to produce a parabolic wave
oldval = val;
val = (phase*phase);
// Recalculate scale factor if needed
if(*freq != prevfreq){
prevfreq = *freq;
scalefac = SAMPLERATE / (8.f * prevfreq * (1.f - prevfreq/SAMPLERATE));
}
// Differentiate and write the output, scaled to +-1
out[i] = (val-oldval) * scalefac;
prevfreq = *freq;
++freq;
}
// store state back to the struct
unit->mPhase = phase;
unit->mVal = val;
unit->mFreq = prevfreq;
unit->mScalefac = scalefac;
}
void SawDPW_next_k(SawDPW *unit, int inNumSamples)
{
float *out = OUT(0);
float freq = IN0(0) * unit->mFreqMul;
float val = unit->mVal;
double phase = unit->mPhase;
float oldval;
// Recalculate scale factor if needed
float scalefac;
if(freq != unit->mFreq){
unit->mFreq = freq;
scalefac = 1.f / (4.f * freq * (1.f - freq/SAMPLERATE));
unit->mScalefac = scalefac;
}else{
scalefac = unit->mScalefac;
}
for (int i=0; i < inNumSamples; ++i)
{
// The "phase" is our modulo counter, -1 to 1
phase += freq;
if(phase >= 1.) phase -= 2.;
if(phase < -1.) phase += 2.;
// Square the phase to produce a parabolic wave
oldval = val;
val = (phase*phase);
//Print("val %g, oldval %g\n", val, oldval);
// Differentiate and write the output, scaled to +-1
//out[i] = (val-oldval) * SAMPLERATE / (4.f * freq * (1.f - freq/SAMPLERATE)); // Differentiate and scale amplitude to +-1
out[i] = (val-oldval) * scalefac; // Differentiate and scale amplitude to +-1
}
// store state back to the struct
unit->mPhase = phase;
unit->mVal = val;
}
PluginLoad(MCLDOsc)
{
ft = inTable;
DefineSimpleUnit(SawDPW);
}
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