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/**
* OpenAL cross platform audio library
* Copyright (C) 2011 by Chris Robinson
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
* Or go to http://www.gnu.org/copyleft/lgpl.html
*/
#include "config.h"
#include "AL/al.h"
#include "AL/alc.h"
#include "alMain.h"
typedef struct {
ALsizei num_angles;
ALsizei max_angle;
ALshort coeffs[][2][HRTF_LENGTH];
} HrtfFilterCoeffs;
#include "hrtf_tables.inc"
static void get_angle_coeffs(const HrtfFilterCoeffs *elev, ALfloat angle, const ALshort **left, const ALshort **right)
{
if(angle < 0)
{
int idx = ((angle > -elev->max_angle) ?
(int)(angle*(elev->num_angles-1)/-elev->max_angle + 0.5) :
(elev->num_angles-1));
*left = elev->coeffs[idx][1];
*right = elev->coeffs[idx][0];
}
else
{
int idx = ((angle < elev->max_angle) ?
(int)(angle*(elev->num_angles-1)/elev->max_angle + 0.5) :
(elev->num_angles-1));
*left = elev->coeffs[idx][0];
*right = elev->coeffs[idx][1];
}
}
void GetHrtfCoeffs(ALfloat elevation, ALfloat angle, const ALshort **left, const ALshort **right)
{
int idx;
if(elevation > 90.f) elevation = 90.f - (elevation - 90.f);
else if(elevation < -90.f) elevation = -90.f - (elevation - -90.f);
idx = (int)(elevation/10.0 + 0.5);
if(idx >= 9) return get_angle_coeffs(&Elev90, angle, left, right);
if(idx >= 8) return get_angle_coeffs(&Elev80, angle, left, right);
if(idx >= 7) return get_angle_coeffs(&Elev70, angle, left, right);
if(idx >= 6) return get_angle_coeffs(&Elev60, angle, left, right);
if(idx >= 5) return get_angle_coeffs(&Elev50, angle, left, right);
if(idx >= 4) return get_angle_coeffs(&Elev40, angle, left, right);
if(idx >= 3) return get_angle_coeffs(&Elev30, angle, left, right);
if(idx >= 2) return get_angle_coeffs(&Elev20, angle, left, right);
if(idx >= 1) return get_angle_coeffs(&Elev10, angle, left, right);
if(idx >= 0) return get_angle_coeffs(&Elev0, angle, left, right);
if(idx >= -1) return get_angle_coeffs(&Elev10n, angle, left, right);
if(idx >= -2) return get_angle_coeffs(&Elev20n, angle, left, right);
if(idx >= -3) return get_angle_coeffs(&Elev30n, angle, left, right);
return get_angle_coeffs(&Elev40n, angle, left, right);
}
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