AuroraOpenALSoft/Alc/hrtf.h

#ifndef ALC_HRTF_H
#define ALC_HRTF_H

#include "AL/al.h"
#include "AL/alc.h"

enum DevFmtChannels;

struct Hrtf;

#define HRIR_BITS        (7)
#define HRIR_LENGTH      (1<<HRIR_BITS)
#define HRIR_MASK        (HRIR_LENGTH-1)
#define HRTFDELAY_BITS    (20)
#define HRTFDELAY_FRACONE (1<<HRTFDELAY_BITS)
#define HRTFDELAY_MASK    (HRTFDELAY_FRACONE-1)

const struct Hrtf *GetHrtf(enum DevFmtChannels chans, ALCuint srate);
ALCboolean FindHrtfFormat(enum DevFmtChannels *chans, ALCuint *srate);

void FreeHrtfs(void);

ALuint GetHrtfIrSize(const struct Hrtf *Hrtf);
void GetLerpedHrtfCoeffs(const struct Hrtf *Hrtf, ALfloat elevation, ALfloat azimuth, ALfloat (*coeffs)[2], ALuint *delays);

#endif /* ALC_HRTF_H */
Move HRTF macros and function declarations to a separate header 2014-02-24 05:11:01 +00:00			`#ifndef ALC_HRTF_H`
			`#define ALC_HRTF_H`

			`#include "AL/al.h"`
			`#include "AL/alc.h"`

			`enum DevFmtChannels;`

			`struct Hrtf;`

			`#define HRIR_BITS (7)`
			`#define HRIR_LENGTH (1<<HRIR_BITS)`
			`#define HRIR_MASK (HRIR_LENGTH-1)`
			`#define HRTFDELAY_BITS (20)`
			`#define HRTFDELAY_FRACONE (1<<HRTFDELAY_BITS)`
			`#define HRTFDELAY_MASK (HRTFDELAY_FRACONE-1)`

Don't pass the device to HRTF methods 2014-06-20 23:43:14 +00:00			`const struct Hrtf *GetHrtf(enum DevFmtChannels chans, ALCuint srate);`
			`ALCboolean FindHrtfFormat(enum DevFmtChannels chans, ALCuint srate);`
Move HRTF macros and function declarations to a separate header 2014-02-24 05:11:01 +00:00
			`void FreeHrtfs(void);`

			`ALuint GetHrtfIrSize(const struct Hrtf *Hrtf);`
Use a different method for HRTF mixing This new method mixes sources normally into a 14-channel buffer with the channels placed all around the listener. HRTF is then applied to the channels given their positions and written to a 2-channel buffer, which gets written out to the device. This method has the benefit that HRTF processing becomes more scalable. The costly HRTF filters are applied to the 14-channel buffer after the mix is done, turning it into a post-process with a fixed overhead. Mixing sources is done with normal non-HRTF methods, so increasing the number of playing sources only incurs normal mixing costs. Another benefit is that it improves B-Format playback since the soundfield gets mixed into speakers covering all three dimensions, which then get filtered based on their locations. The main downside to this is that the spatial resolution of the HRTF dataset does not play a big role anymore. However, the hope is that with ambisonics- based panning, the perceptual position of panned sounds will still be good. It is also an option to increase the number of virtual channels for systems that can handle it, or maybe even decrease it for weaker systems. 2014-11-22 12:20:17 +00:00			`void GetLerpedHrtfCoeffs(const struct Hrtf Hrtf, ALfloat elevation, ALfloat azimuth, ALfloat (coeffs)[2], ALuint *delays);`
Move HRTF macros and function declarations to a separate header 2014-02-24 05:11:01 +00:00
			`#endif /* ALC_HRTF_H */`