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#ifndef ALC_HRTF_H
#define ALC_HRTF_H
#include <array>
#include <cstddef>
#include <memory>
#include <string>
#include "AL/al.h"
#include "almalloc.h"
#include "alspan.h"
#include "ambidefs.h"
#include "atomic.h"
#include "vector.h"
#define HRTF_HISTORY_BITS (6)
#define HRTF_HISTORY_LENGTH (1<<HRTF_HISTORY_BITS)
#define HRTF_HISTORY_MASK (HRTF_HISTORY_LENGTH-1)
#define HRIR_BITS (7)
#define HRIR_LENGTH (1<<HRIR_BITS)
#define HRIR_MASK (HRIR_LENGTH-1)
#define MIN_IR_LENGTH (8)
using float2 = std::array<float,2>;
using HrirArray = std::array<float2,HRIR_LENGTH>;
using ubyte2 = std::array<ALubyte,2>;
struct HrtfStore {
RefCount mRef;
ALuint sampleRate;
ALuint irSize;
struct Field {
ALfloat distance;
ALubyte evCount;
};
/* NOTE: Fields are stored *backwards*. field[0] is the farthest field, and
* field[fdCount-1] is the nearest.
*/
ALuint fdCount;
const Field *field;
struct Elevation {
ALushort azCount;
ALushort irOffset;
};
Elevation *elev;
const HrirArray *coeffs;
const ubyte2 *delays;
void IncRef();
void DecRef();
DEF_PLACE_NEWDEL()
};
struct HrtfState {
alignas(16) std::array<float,HRTF_HISTORY_LENGTH> History;
};
struct HrtfFilter {
alignas(16) HrirArray Coeffs;
ALuint Delay[2];
float Gain;
};
struct DirectHrtfState {
/* HRTF filter state for dry buffer content */
ALuint IrSize{0};
al::FlexArray<HrirArray,16> Coeffs;
DirectHrtfState(size_t numchans) : Coeffs{numchans} { }
static std::unique_ptr<DirectHrtfState> Create(size_t num_chans);
DEF_FAM_NEWDEL(DirectHrtfState, Coeffs)
};
struct EvRadians { float value; };
struct AzRadians { float value; };
struct AngularPoint {
EvRadians Elev;
AzRadians Azim;
};
al::vector<std::string> EnumerateHrtf(const char *devname);
HrtfStore *GetLoadedHrtf(const std::string &name, const char *devname, const ALuint devrate);
void GetHrtfCoeffs(const HrtfStore *Hrtf, float elevation, float azimuth, float distance,
float spread, HrirArray &coeffs, ALuint (&delays)[2]);
/**
* Produces HRTF filter coefficients for decoding B-Format, given a set of
* virtual speaker positions, a matching decoding matrix, and per-order high-
* frequency gains for the decoder. The calculated impulse responses are
* ordered and scaled according to the matrix input.
*/
void BuildBFormatHrtf(const HrtfStore *Hrtf, DirectHrtfState *state,
const al::span<const AngularPoint> AmbiPoints, const float (*AmbiMatrix)[MAX_AMBI_CHANNELS],
const al::span<const float,MAX_AMBI_ORDER+1> AmbiOrderHFGain);
#endif /* ALC_HRTF_H */
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