https://cycling74.com/forums/topic/wdl-oliplug-project-for-gen-code-export/?reply_id=311742

in constructor

  //Fill the mAudioToResample array with 100 cycles of a 441hz sine wave
  double recip = 1. / 44100.;
  double phase = 0.;
  
  for (int i = 0; i< 44100; i++)
  {
    mAudioToResampleL[i] = sin( phase * 6.283185307179586);
    mAudioToResampleR[i] = mAudioToResampleL[i] * -1.;   // just for example
    phase += recip * 441.;
    if (phase > 1.) phase -= 1.;
  }
  
  mSampleIndxL = 0;
  mSampleIndxR = 0;
  mResamplerL.SetMode(true, 1, false, 0, 0);
  mResamplerR.SetMode(true, 1, false, 0, 0);
  mResamplerL.SetFilterParms();
  mResamplerR.SetFilterParms();
  mResamplerL.SetFeedMode(false);
  mResamplerR.SetFeedMode(false);
  mResamplerL.SetRates(44100., GetSampleRate());
  mResamplerR.SetRates(44100., GetSampleRate());

IPlugGenTwoInputs

class IPlugGenTwoInputs : public IPlug
{
public:
  IPlugGenTwoInputs(IPlugInstanceInfo instanceInfo);
  ~IPlugGenTwoInputs();

  void Reset();
  void OnParamChange(int paramIdx);
  void ProcessDoubleReplacing(double** inputs, double** outputs, int nFrames);

private:
  
  int mSampleIndxL, mSampleIndxR;
  WDL_Resampler mResamplerL, mResamplerR;
  WDL_ResampleSample mAudioToResampleL[44100];
  WDL_ResampleSample mAudioToResampleR[44100];
  double mGain;
  CommonState *gen;
};

process replacing

void IPlugGenTwoInputs::ProcessDoubleReplacing(double** inputs, double** outputs, int nFrames)
{
  // Mutex is already locked for us.
  
  double* inL = inputs[0];
  double* inR = inputs[1];
  
  // DO LEFT CHANNEL ---------------------------------------------------------
  
  WDL_ResampleSample *resampledAudioL=NULL;
  int numSamplesL = mResamplerL.ResamplePrepare(nFrames, 1, &resampledAudioL);
  
  for (int s = 0; s < numSamplesL; s++)
  {
    if (mSampleIndxL >= 44100)
      mSampleIndxL = 0;
      
    resampledAudioL[s] = mAudioToResampleL[mSampleIndxL++] * mGain;
  }
  
  if (mResamplerL.ResampleOut(inL, numSamplesL, nFrames, 1) != nFrames)
  {
    //failed somehow
    memset(inL, 0 , nFrames * sizeof(double));
  }
  
  // DO RIGHT CHANNEL ---------------------------------------------------------
  
  WDL_ResampleSample *resampledAudioR=NULL;
  int numSamplesR = mResamplerR.ResamplePrepare(nFrames, 1, &resampledAudioR);
  
  for (int s = 0; s < numSamplesR; s++)
  {
    if (mSampleIndxR >= 44100)
      mSampleIndxR = 0;
      
    resampledAudioR[s] = mAudioToResampleR[resampledAudioR++] * mGain;
  }
  
  if (mResamplerR.ResampleOut(inR, numSamplesR, nFrames, 1) != nFrames)
  {
    //failed somehow
    memset(inR, 0 , nFrames * sizeof(double));
  }
  //---------------------------------------------------------
  
  //input buffers now contain the two resampled sound sources
  perform(gen, inputs, num_inputs(), outputs, num_outputs(), nFrames);
}