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 sampleRate;
  24     uint irSize;
  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     uint fdCount;
  34     const Field *field;
  35
  36     struct Elevation {
  37         ushort azCount;
  38         ushort irOffset;
  39     };
  40     Elevation *elev;
  41     const HrirArray *coeffs;
  42     const ubyte2 *delays;
  43
  44     void add_ref();
  45     void dec_ref();
  46
  47     DEF_PLACE_NEWDEL()
  48 };
  49 using HrtfStorePtr = al::intrusive_ptr<HrtfStore>;
  50
  51
  52 struct EvRadians { float value; };
  53 struct AzRadians { float value; };
  54 struct AngularPoint {
  55     EvRadians Elev;
  56     AzRadians Azim;
  57 };
  58
  59
  60 struct DirectHrtfState {
  61     std::array<float,BufferLineSize> mTemp;
  62
  63     /* HRTF filter state for dry buffer content */
  64     uint mIrSize{0};
  65     al::FlexArray<HrtfChannelState> mChannels;
  66
  67     DirectHrtfState(size_t numchans) : mChannels{numchans} { }
  68     /**
  69      * Produces HRTF filter coefficients for decoding B-Format, given a set of
  70      * virtual speaker positions, a matching decoding matrix, and per-order
  71      * high-frequency gains for the decoder. The calculated impulse responses
  72      * are ordered and scaled according to the matrix input.
  73      */
  74     void build(const HrtfStore *Hrtf, const uint irSize, const bool perHrirMin,
  75         const al::span<const AngularPoint> AmbiPoints, const float (*AmbiMatrix)[MaxAmbiChannels],
  76         const float XOverFreq, const al::span<const float,MaxAmbiOrder+1> AmbiOrderHFGain);
  77
  78     static std::unique_ptr<DirectHrtfState> Create(size_t num_chans);
  79
  80     DEF_FAM_NEWDEL(DirectHrtfState, mChannels)
  81 };
  82
  83
  84 al::vector<std::string> EnumerateHrtf(al::optional<std::string> pathopt);
  85 HrtfStorePtr GetLoadedHrtf(const std::string &name, const uint devrate);
  86
  87 void GetHrtfCoeffs(const HrtfStore *Hrtf, float elevation, float azimuth, float distance,
  88     float spread, HrirArray &coeffs, const al::span<uint,2> delays);
  89
  90 #endif /* CORE_HRTF_H */