Alc/hrtf.h

   1 #ifndef ALC_HRTF_H
   2 #define ALC_HRTF_H
   3
   4 #include "AL/al.h"
   5 #include "AL/alc.h"
   6
   7 #include "alMain.h"
   8 #include "alstring.h"
   9 #include "atomic.h"
  10
  11
  12 /* The maximum number of virtual speakers used to generate HRTF coefficients
  13  * for decoding B-Format.
  14  */
  15 #define HRTF_AMBI_MAX_CHANNELS 18
  16
  17
  18 #define HRTF_HISTORY_BITS   (6)
  19 #define HRTF_HISTORY_LENGTH (1<<HRTF_HISTORY_BITS)
  20 #define HRTF_HISTORY_MASK   (HRTF_HISTORY_LENGTH-1)
  21
  22 #define HRIR_BITS        (7)
  23 #define HRIR_LENGTH      (1<<HRIR_BITS)
  24 #define HRIR_MASK        (HRIR_LENGTH-1)
  25
  26
  27 struct HrtfEntry;
  28
  29 struct Hrtf {
  30     RefCount ref;
  31
  32     ALuint sampleRate;
  33     ALsizei irSize;
  34
  35     ALfloat distance;
  36     ALubyte evCount;
  37
  38     const ALubyte *azCount;
  39     const ALushort *evOffset;
  40     const ALfloat (*coeffs)[2];
  41     const ALubyte (*delays)[2];
  42 };
  43
  44
  45 typedef struct HrtfState {
  46     alignas(16) ALfloat History[HRTF_HISTORY_LENGTH];
  47     alignas(16) ALfloat Values[HRIR_LENGTH][2];
  48 } HrtfState;
  49
  50 typedef struct HrtfParams {
  51     alignas(16) ALfloat Coeffs[HRIR_LENGTH][2];
  52     ALsizei Delay[2];
  53     ALfloat Gain;
  54 } HrtfParams;
  55
  56 typedef struct DirectHrtfState {
  57     /* HRTF filter state for dry buffer content */
  58     ALsizei Offset;
  59     ALsizei IrSize;
  60     struct {
  61         alignas(16) ALfloat Values[HRIR_LENGTH][2];
  62         alignas(16) ALfloat Coeffs[HRIR_LENGTH][2];
  63     } Chan[];
  64 } DirectHrtfState;
  65
  66 struct AngularPoint {
  67     ALfloat Elev;
  68     ALfloat Azim;
  69 };
  70
  71
  72 void FreeHrtfs(void);
  73
  74 vector_EnumeratedHrtf EnumerateHrtf(const_al_string devname);
  75 void FreeHrtfList(vector_EnumeratedHrtf *list);
  76 struct Hrtf *GetLoadedHrtf(struct HrtfEntry *entry);
  77 void Hrtf_IncRef(struct Hrtf *hrtf);
  78 void Hrtf_DecRef(struct Hrtf *hrtf);
  79
  80 void GetHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azimuth, ALfloat spread, ALfloat (*coeffs)[2], ALsizei *delays);
  81
  82 /**
  83  * Produces HRTF filter coefficients for decoding B-Format, given a set of
  84  * virtual speaker positions and HF/LF matrices for decoding to them. The
  85  * returned coefficients are ordered and scaled according to the matrices.
  86  */
  87 void BuildBFormatHrtf(const struct Hrtf *Hrtf, DirectHrtfState *state, ALsizei NumChannels, const struct AngularPoint *AmbiPoints, const ALfloat (*restrict AmbiMatrix)[MAX_AMBI_COEFFS], ALsizei AmbiCount, const ALfloat *restrict AmbiOrderHFGain);
  88
  89 #endif /* ALC_HRTF_H */