DspRfft.cpp

/*
 *  Copyright 2010 Reality Jockey, Ltd.
 *                 info@rjdj.me
 *                 http://rjdj.me/
 *
 *  This file is part of ZenGarden.
 *
 *  ZenGarden is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  ZenGarden is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with ZenGarden.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "ArrayArithmetic.h"
#include "BufferPool.h"
#include "DspRfft.h"
#include "PdGraph.h"

MessageObject *DspRfft::newObject(PdMessage *initMessage, PdGraph *graph) {
  return new DspRfft(initMessage, graph);
}

DspRfft::DspRfft(PdMessage *initMessage, PdGraph *graph) : DspObject(0, 1, 0, 2, graph) {
  #if __APPLE__
  log2n = lrintf(log2f((float) blockSizeInt));
  fftSetup = vDSP_create_fftsetup(log2n, kFFTRadix2);
  zeroBuffer = graph->getBufferPool()->getZeroBuffer(); // cache the local zero buffer
  #else
  graph->printErr("[rfft~] is not supported on this platform. It is only supported on Apple OS X and iOS platforms.");
  #endif // __APPLE__
  
  processFunction = &processSignal;
}

DspRfft::~DspRfft() {
  #if __APPLE__
  vDSP_destroy_fftsetup(fftSetup);
  #endif // __APPLE__
}

void DspRfft::processSignal(DspObject *dspObject, int fromIndex, int toIndex) {
  DspRfft *d = reinterpret_cast<DspRfft *>(dspObject);
  
  #if __APPLE__
  DSPSplitComplex inputVector;
  inputVector.realp = d->dspBufferAtInlet[0];
  inputVector.imagp = d->zeroBuffer;
  DSPSplitComplex outputVector;
  outputVector.realp = d->dspBufferAtOutlet[0];
  outputVector.imagp = d->dspBufferAtOutlet[1];
  vDSP_fft_zop(d->fftSetup, &inputVector, 1, &outputVector, 1, d->log2n, kFFTDirection_Forward);
  
  // NOTE(mhroth): vDSP_fft_zop outputs the entire series of symmetric coefficients.
  // Pd only returns the unique values. The below code makes this object output values in the same
  // way that Pd does. But since the Apple fft and ifft functions require the symmetric values,
  // we leave it like this for now.
  
  //int halfBlockSize = blockSizeInt >> 1;
  //memset(dspBufferAtOutlet0+halfBlockSize+1, 0, (halfBlockSize-1) * sizeof(float));
  //memset(dspBufferAtOutlet[1]+halfBlockSize, 0, halfBlockSize * sizeof(float));
  #endif // __APPLE__
}