core/hrtf.h

   1 #ifndef CORE_HRTF_H
   2 #define CORE_HRTF_H
   3
   4 #include <array>
   5 #include <cstddef>
   6 #include <memory>
   7 #include <string>
   8
   9 #include "almalloc.h"
  10 #include "aloptional.h"
  11 #include "alspan.h"
  12 #include "atomic.h"
  13 #include "ambidefs.h"
  14 #include "bufferline.h"
  15 #include "mixer/hrtfdefs.h"
  16 #include "intrusive_ptr.h"
  17 #include "vector.h"
  18
  19
  20 struct HrtfStore {
  21     RefCount mRef;
  22
  23     uint mSampleRate : 24;
  24     uint mIrSize : 8;
  25
  26     struct Field {
  27         float distance;
  28         ubyte evCount;
  29     };
  30     /* NOTE: Fields are stored *backwards*. field[0] is the farthest field, and
  31      * field[fdCount-1] is the nearest.
  32      */
  33     al::span<const Field> mFields;
  34
  35     struct Elevation {
  36         ushort azCount;
  37         ushort irOffset;
  38     };
  39     Elevation *mElev;
  40     const HrirArray *mCoeffs;
  41     const ubyte2 *mDelays;
  42
  43     void getCoeffs(float elevation, float azimuth, float distance, float spread, HrirArray &coeffs,
  44         const al::span<uint,2> delays);
  45
  46     void add_ref();
  47     void dec_ref();
  48
  49     DEF_PLACE_NEWDEL()
  50 };
  51 using HrtfStorePtr = al::intrusive_ptr<HrtfStore>;
  52
  53
  54 struct EvRadians { float value; };
  55 struct AzRadians { float value; };
  56 struct AngularPoint {
  57     EvRadians Elev;
  58     AzRadians Azim;
  59 };
  60
  61
  62 struct DirectHrtfState {
  63     std::array<float,BufferLineSize> mTemp;
  64
  65     /* HRTF filter state for dry buffer content */
  66     uint mIrSize{0};
  67     al::FlexArray<HrtfChannelState> mChannels;
  68
  69     DirectHrtfState(size_t numchans) : mChannels{numchans} { }
  70     /**
  71      * Produces HRTF filter coefficients for decoding B-Format, given a set of
  72      * virtual speaker positions, a matching decoding matrix, and per-order
  73      * high-frequency gains for the decoder. The calculated impulse responses
  74      * are ordered and scaled according to the matrix input.
  75      */
  76     void build(const HrtfStore *Hrtf, const uint irSize, const bool perHrirMin,
  77         const al::span<const AngularPoint> AmbiPoints, const float (*AmbiMatrix)[MaxAmbiChannels],
  78         const float XOverFreq, const al::span<const float,MaxAmbiOrder+1> AmbiOrderHFGain);
  79
  80     static std::unique_ptr<DirectHrtfState> Create(size_t num_chans);
  81
  82     DEF_FAM_NEWDEL(DirectHrtfState, mChannels)
  83 };
  84
  85
  86 al::vector<std::string> EnumerateHrtf(al::optional<std::string> pathopt);
  87 HrtfStorePtr GetLoadedHrtf(const std::string &name, const uint devrate);
  88
  89 #endif /* CORE_HRTF_H */