bsnes/nall/dsp/resampler/cubic.hpp

71 lines
1.6 KiB
C++

#pragma once
#include <nall/queue.hpp>
#include <nall/dsp/dsp.hpp>
namespace nall::DSP::Resampler {
struct Cubic {
inline auto reset(double inputFrequency, double outputFrequency = 0, uint queueSize = 0) -> void;
inline auto setInputFrequency(double inputFrequency) -> void;
inline auto pending() const -> bool;
inline auto read() -> double;
inline auto write(double sample) -> void;
private:
double inputFrequency;
double outputFrequency;
double ratio;
double fraction;
double history[4];
queue<double> samples;
};
auto Cubic::reset(double inputFrequency, double outputFrequency, uint queueSize) -> void {
this->inputFrequency = inputFrequency;
this->outputFrequency = outputFrequency ? outputFrequency : this->inputFrequency;
ratio = inputFrequency / outputFrequency;
fraction = 0.0;
for(auto& sample : history) sample = 0.0;
samples.resize(queueSize ? queueSize : this->outputFrequency * 0.02); //default to 20ms max queue size
}
auto Cubic::setInputFrequency(double inputFrequency) -> void {
this->inputFrequency = inputFrequency;
ratio = inputFrequency / outputFrequency;
}
auto Cubic::pending() const -> bool {
return samples.pending();
}
auto Cubic::read() -> double {
return samples.read();
}
auto Cubic::write(double sample) -> void {
auto& mu = fraction;
auto& s = history;
s[0] = s[1];
s[1] = s[2];
s[2] = s[3];
s[3] = sample;
while(mu <= 1.0) {
double A = s[3] - s[2] - s[0] + s[1];
double B = s[0] - s[1] - A;
double C = s[2] - s[0];
double D = s[1];
samples.write(A * mu * mu * mu + B * mu * mu + C * mu + D);
mu += ratio;
}
mu -= 1.0;
}
}