yaw-audio/src/yaw-vowel/filter.h

70 lines
1.6 KiB
C++

#include "DistrhoPlugin.hpp"
#include <tuple>
#include <array>
class Resonator
{
public:
Resonator():
xp(0), xpp(0), yp(0), ypp(0), app(0), ap(0), scale(1){};
void process(float *output, const float *const input, uint32_t frames);
void clear();
void set(double _app, double _ap, double _scale);
private:
float xp;
float xpp;
float yp;
float ypp;
double app;
double ap;
double scale;
};
class Filter
{
public:
Filter(){};
void process(float **outputs, const float **inputs, uint32_t frames)
{
for (uint chn = 0; chn < 2; ++chn)
{
for (uint32_t j = 0; j < frames; ++j)
{
outputs[chn][j] = inputs[chn][j];
}
for (auto& r : res[chn])
{
r.process(outputs[chn], outputs[chn], frames);
}
}
}
//Compute filter coefficients from
//frequency as a proportion of the sample rate
//REMEMBER: THAT'S DOUBLE THE Nyquist RATE, dummy
//and resonance in [0, 1]
void set(double x, double y, double p)
{
double r = p * 0.99;
double app = r * r;
double xap = (1.0 + r * r) * cos(M_PI * x);
double yap = (1.0 + r * r) * cos(M_PI * y);
double scale = sqrt(0.5 - 0.5 * r * r);
for (auto& channelFilter : res)
{
channelFilter[0].set(app, xap, scale);
channelFilter[1].set(app, xap, scale);
channelFilter[2].set(app, yap, scale);
channelFilter[3].set(app, yap, scale);
}
}
private:
std::array<std::array<Resonator, 4>, 2> res;
};