alc/filters/splitter.h

   1 #ifndef FILTER_SPLITTER_H
   2 #define FILTER_SPLITTER_H
   3
   4 #include <cstddef>
   5
   6 #include "alspan.h"
   7
   8
   9 /* Band splitter. Splits a signal into two phase-matching frequency bands. */
  10 template<typename Real>
  11 class BandSplitterR {
  12     Real mCoeff{0.0f};
  13     Real mLpZ1{0.0f};
  14     Real mLpZ2{0.0f};
  15     Real mApZ1{0.0f};
  16
  17 public:
  18     BandSplitterR() = default;
  19     BandSplitterR(const BandSplitterR&) = default;
  20     BandSplitterR(Real f0norm) { init(f0norm); }
  21
  22     void init(Real f0norm);
  23     void clear() noexcept { mLpZ1 = mLpZ2 = mApZ1 = 0.0f; }
  24     void process(const al::span<const Real> input, Real *hpout, Real *lpout);
  25
  26     void processHfScale(const al::span<Real> samples, const Real hfscale);
  27
  28     /* The all-pass portion of the band splitter. Applies the same phase shift
  29      * without splitting the signal. Note that each use of this method is
  30      * indepedent, it does not track history between calls.
  31      */
  32     void applyAllpass(const al::span<Real> samples) const;
  33 };
  34 using BandSplitter = BandSplitterR<float>;
  35
  36 #endif /* FILTER_SPLITTER_H */