mirror of https://github.com/bsnes-emu/bsnes.git
101 lines
3.8 KiB
C++
Executable File
101 lines
3.8 KiB
C++
Executable File
/***************************************************************************
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* Copyright (C) 2008 by Sindre Aamås *
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* aamas@stud.ntnu.no *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License version 2 as *
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* published by the Free Software Foundation. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License version 2 for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* version 2 along with this program; if not, write to the *
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* Free Software Foundation, Inc., *
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
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***************************************************************************/
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#ifndef BLACKMANSINC_H
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#define BLACKMANSINC_H
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#include "convoluter.h"
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#include "subresampler.h"
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#include "makesinckernel.h"
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#include "cic4.h"
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#include <cmath>
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#include <cstdlib>
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template<unsigned channels, unsigned phases>
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class BlackmanSinc : public SubResampler {
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PolyPhaseConvoluter<channels, phases> convoluters[channels];
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short *kernel;
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static double blackmanWin(const long i, const long M) {
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static const double PI = 3.14159265358979323846;
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return 0.42 - 0.5 * std::cos(2 * PI * i / M) + 0.08 * std::cos(4 * PI * i / M);
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}
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void init(unsigned div, unsigned phaseLen, double fc);
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public:
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enum { MUL = phases };
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typedef Cic4<channels> Cic;
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static float cicLimit() { return 4.7f; }
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class RollOff {
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static unsigned toTaps(const float rollOffWidth) {
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static const float widthTimesTaps = 4.5f;
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return std::ceil(widthTimesTaps / rollOffWidth);
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}
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static float toFc(const float rollOffStart, const int taps) {
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static const float startToFcDeltaTimesTaps = 1.69f;
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return startToFcDeltaTimesTaps / taps + rollOffStart;
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}
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public:
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const unsigned taps;
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const float fc;
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RollOff(float rollOffStart, float rollOffWidth) : taps(toTaps(rollOffWidth)), fc(toFc(rollOffStart, taps)) {}
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};
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BlackmanSinc(unsigned div, unsigned phaseLen, double fc) { init(div, phaseLen, fc); }
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BlackmanSinc(unsigned div, RollOff ro) { init(div, ro.taps, ro.fc); }
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~BlackmanSinc() { delete[] kernel; }
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std::size_t resample(short *out, const short *in, std::size_t inlen);
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void adjustDiv(unsigned div);
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unsigned mul() const { return MUL; }
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unsigned div() const { return convoluters[0].div(); }
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};
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template<const unsigned channels, const unsigned phases>
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void BlackmanSinc<channels, phases>::init(const unsigned div, const unsigned phaseLen, const double fc) {
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kernel = new short[phaseLen * phases];
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makeSincKernel(kernel, phases, phaseLen, fc, blackmanWin);
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for (unsigned i = 0; i < channels; ++i)
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convoluters[i].reset(kernel, phaseLen, div);
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}
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template<const unsigned channels, const unsigned phases>
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std::size_t BlackmanSinc<channels, phases>::resample(short *const out, const short *const in, const std::size_t inlen) {
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std::size_t samplesOut;
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for (unsigned i = 0; i < channels; ++i)
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samplesOut = convoluters[i].filter(out + i, in + i, inlen);
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return samplesOut;
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}
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template<const unsigned channels, const unsigned phases>
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void BlackmanSinc<channels, phases>::adjustDiv(const unsigned div) {
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for (unsigned i = 0; i < channels; ++i)
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convoluters[i].adjustDiv(div);
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}
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#endif
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