Window a buffer for sampling

gistfile1.m

@implementation SamplerKit

+ (void) windowBuffer: (AVAudioPCMBuffer*)buffer rampFrames:(AVAudioFrameCount)_rampFrames{
  int frames = [buffer frameLength];

  float* _windowBuffer = (float*) malloc(sizeof(float) * frames);

  float min = 0.0f;
  float max = 1.0f;

  vDSP_vfill (&max, _windowBuffer, 1, frames);
  vDSP_vgen (&min, &max, _windowBuffer, 1, _rampFrames);
  vDSP_vsq (_windowBuffer, 1, _windowBuffer, 1, _rampFrames);
  vDSP_vrvrs (_windowBuffer, 1, frames );
  vDSP_vgen (&min, &max, _windowBuffer, 1, _rampFrames);
  vDSP_vsq (_windowBuffer, 1, _windowBuffer, 1, _rampFrames);

  for (int i=0; i < buffer.audioBufferList->mNumberBuffers; i++) {
    AudioBuffer buf = buffer.audioBufferList->mBuffers[i];
    for (int currentChannel=0; currentChannel < buf.mNumberChannels; currentChannel++) {
      vDSP_vmul( _windowBuffer, 1, buf.mData, 1, buf.mData, 1, frames );
    }
  }
}

@end