bsnes/higan/nall/dsp/resample/hermite.hpp

63 lines
1.5 KiB
C++
Executable File

#ifdef NALL_DSP_INTERNAL_HPP
struct ResampleHermite : Resampler {
inline void setFrequency();
inline void clear();
inline void sample();
ResampleHermite(DSP &dsp) : Resampler(dsp) {}
real fraction;
real step;
};
void ResampleHermite::setFrequency() {
fraction = 0.0;
step = dsp.settings.frequency / frequency;
}
void ResampleHermite::clear() {
fraction = 0.0;
}
void ResampleHermite::sample() {
while(fraction <= 1.0) {
real channel[dsp.settings.channels];
for(unsigned n = 0; n < dsp.settings.channels; n++) {
real a = dsp.buffer.read(n, -3);
real b = dsp.buffer.read(n, -2);
real c = dsp.buffer.read(n, -1);
real d = dsp.buffer.read(n, -0);
const real tension = 0.0; //-1 = low, 0 = normal, +1 = high
const real bias = 0.0; //-1 = left, 0 = even, +1 = right
real mu1, mu2, mu3, m0, m1, a0, a1, a2, a3;
mu1 = fraction;
mu2 = mu1 * mu1;
mu3 = mu2 * mu1;
m0 = (b - a) * (1.0 + bias) * (1.0 - tension) / 2.0;
m0 += (c - b) * (1.0 - bias) * (1.0 - tension) / 2.0;
m1 = (c - b) * (1.0 + bias) * (1.0 - tension) / 2.0;
m1 += (d - c) * (1.0 - bias) * (1.0 - tension) / 2.0;
a0 = +2 * mu3 - 3 * mu2 + 1;
a1 = mu3 - 2 * mu2 + mu1;
a2 = mu3 - mu2;
a3 = -2 * mu3 + 3 * mu2;
channel[n] = (a0 * b) + (a1 * m0) + (a2 * m1) + (a3 * c);
}
dsp.write(channel);
fraction += step;
}
dsp.buffer.rdoffset++;
fraction -= 1.0;
}
#endif