413 lines
15 KiB
C
413 lines
15 KiB
C
/**
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* OpenAL cross platform audio library
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* Copyright (C) 2011 by Chris Robinson
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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* Or go to http://www.gnu.org/copyleft/lgpl.html
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*/
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#include "config.h"
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#include "AL/al.h"
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#include "AL/alc.h"
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#include "alMain.h"
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#include "alSource.h"
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/* External HRTF file format (LE byte order):
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*
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* ALchar magic[8] = "MinPHR00";
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* ALuint sampleRate;
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*
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* ALushort hrirCount; // Required value: 828
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* ALushort hrirSize; // Required value: 32
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* ALubyte evCount; // Required value: 19
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*
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* ALushort evOffset[evCount]; // Required values:
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* { 0, 1, 13, 37, 73, 118, 174, 234, 306, 378, 450, 522, 594, 654, 710, 755, 791, 815, 827 }
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*
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* ALushort coefficients[hrirCount][hrirSize];
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* ALubyte delays[hrirCount]; // Element values must not exceed 127
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*/
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static const ALchar magicMarker[8] = "MinPHR00";
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#define HRIR_COUNT 828
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#define ELEV_COUNT 19
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static const ALushort evOffset[ELEV_COUNT] = { 0, 1, 13, 37, 73, 118, 174, 234, 306, 378, 450, 522, 594, 654, 710, 755, 791, 815, 827 };
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static const ALubyte azCount[ELEV_COUNT] = { 1, 12, 24, 36, 45, 56, 60, 72, 72, 72, 72, 72, 60, 56, 45, 36, 24, 12, 1 };
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static struct Hrtf {
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ALuint sampleRate;
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ALshort coeffs[HRIR_COUNT][HRIR_LENGTH];
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ALubyte delays[HRIR_COUNT];
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} Hrtf = {
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44100,
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#include "hrtf_tables.inc"
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};
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// Calculate the elevation indices given the polar elevation in radians.
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// This will return two indices between 0 and (ELEV_COUNT-1) and an
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// interpolation factor between 0.0 and 1.0.
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static void CalcEvIndices(ALfloat ev, ALuint *evidx, ALfloat *evmu)
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{
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ev = (M_PI/2.0f + ev) * (ELEV_COUNT-1) / M_PI;
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evidx[0] = (ALuint)ev;
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evidx[1] = __min(evidx[0] + 1, ELEV_COUNT-1);
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*evmu = ev - evidx[0];
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}
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// Calculate the azimuth indices given the polar azimuth in radians. This
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// will return two indices between 0 and (azCount [ei] - 1) and an
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// interpolation factor between 0.0 and 1.0.
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static void CalcAzIndices(ALuint evidx, ALfloat az, ALuint *azidx, ALfloat *azmu)
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{
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az = (M_PI*2.0f + az) * azCount[evidx] / (M_PI*2.0f);
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azidx[0] = (ALuint)az % azCount[evidx];
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azidx[1] = (azidx[0] + 1) % azCount[evidx];
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*azmu = az - (ALuint)az;
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}
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// Calculates the normalized HRTF transition factor (delta) from the changes
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// in gain and listener to source angle between updates. The result is a
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// normalized delta factor than can be used to calculate moving HRIR stepping
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// values.
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ALfloat CalcHrtfDelta(ALfloat oldGain, ALfloat newGain, const ALfloat olddir[3], const ALfloat newdir[3])
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{
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ALfloat gainChange, angleChange, delta;
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// Calculate the normalized dB gain change.
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gainChange = aluFabs((log10(__max(newGain, 0.0001f)) -
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log10(__max(oldGain, 0.0001f))) / log10(0.0001f));
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// Calculate the normalized listener to source angle change when there is
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// enough gain to notice it.
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angleChange = 0.0f;
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if(gainChange > 0.0001f || newGain > 0.0001f)
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{
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// No angle change when the directions are equal or degenerate (when
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// both have zero length).
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if(newdir[0]-olddir[0] || newdir[1]-olddir[1] || newdir[2]-olddir[2])
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angleChange = aluAcos(olddir[0]*newdir[0] +
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olddir[1]*newdir[1] +
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olddir[2]*newdir[2]) / M_PI;
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}
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// Use the largest of the two changes for the delta factor, and apply a
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// significance shaping function to it.
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delta = __max(gainChange, angleChange) * 2.0f;
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return __min(delta, 1.0f);
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}
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// Calculates static HRIR coefficients and delays for the given polar
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// elevation and azimuth in radians. Linear interpolation is used to
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// increase the apparent resolution of the HRIR dataset. The coefficients
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// are also normalized and attenuated by the specified gain.
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void GetLerpedHrtfCoeffs(ALfloat elevation, ALfloat azimuth, ALfloat gain, ALfloat (*coeffs)[2], ALuint *delays)
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{
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ALuint evidx[2], azidx[2];
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ALfloat mu[3];
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ALuint lidx[4], ridx[4];
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ALuint i;
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// Claculate elevation indices and interpolation factor.
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CalcEvIndices(elevation, evidx, &mu[2]);
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// Calculate azimuth indices and interpolation factor for the first
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// elevation.
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CalcAzIndices(evidx[0], azimuth, azidx, &mu[0]);
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// Calculate the first set of linear HRIR indices for left and right
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// channels.
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lidx[0] = evOffset[evidx[0]] + azidx[0];
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lidx[1] = evOffset[evidx[0]] + azidx[1];
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ridx[0] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[0]) % azCount[evidx[0]]);
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ridx[1] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[1]) % azCount[evidx[0]]);
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// Calculate azimuth indices and interpolation factor for the second
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// elevation.
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CalcAzIndices(evidx[1], azimuth, azidx, &mu[1]);
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// Calculate the second set of linear HRIR indices for left and right
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// channels.
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lidx[2] = evOffset[evidx[1]] + azidx[0];
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lidx[3] = evOffset[evidx[1]] + azidx[1];
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ridx[2] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[0]) % azCount[evidx[1]]);
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ridx[3] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[1]) % azCount[evidx[1]]);
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// Calculate the normalized and attenuated HRIR coefficients using linear
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// interpolation when there is enough gain to warrant it. Zero the
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// coefficients if gain is too low.
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if(gain > 0.0001f)
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{
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ALdouble scale = gain * (1.0/32767.0);
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for(i = 0;i < HRIR_LENGTH;i++)
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{
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coeffs[i][0] = lerp(lerp(Hrtf.coeffs[lidx[0]][i], Hrtf.coeffs[lidx[1]][i], mu[0]),
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lerp(Hrtf.coeffs[lidx[2]][i], Hrtf.coeffs[lidx[3]][i], mu[1]),
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mu[2]) * scale;
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coeffs[i][1] = lerp(lerp(Hrtf.coeffs[ridx[0]][i], Hrtf.coeffs[ridx[1]][i], mu[0]),
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lerp(Hrtf.coeffs[ridx[2]][i], Hrtf.coeffs[ridx[3]][i], mu[1]),
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mu[2]) * scale;
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}
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}
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else
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{
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for(i = 0;i < HRIR_LENGTH;i++)
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{
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coeffs[i][0] = 0.0f;
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coeffs[i][1] = 0.0f;
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}
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}
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// Calculate the HRIR delays using linear interpolation.
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delays[0] = (ALuint)(lerp(lerp(Hrtf.delays[lidx[0]], Hrtf.delays[lidx[1]], mu[0]),
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lerp(Hrtf.delays[lidx[2]], Hrtf.delays[lidx[3]], mu[1]),
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mu[2]) * 65536.0f);
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delays[1] = (ALuint)(lerp(lerp(Hrtf.delays[ridx[0]], Hrtf.delays[ridx[1]], mu[0]),
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lerp(Hrtf.delays[ridx[2]], Hrtf.delays[ridx[3]], mu[1]),
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mu[2]) * 65536.0f);
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}
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// Calculates the moving HRIR target coefficients, target delays, and
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// stepping values for the given polar elevation and azimuth in radians.
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// Linear interpolation is used to increase the apparent resolution of the
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// HRIR dataset. The coefficients are also normalized and attenuated by the
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// specified gain. Stepping resolution and count is determined using the
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// given delta factor between 0.0 and 1.0.
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ALuint GetMovingHrtfCoeffs(ALfloat elevation, ALfloat azimuth, ALfloat gain, ALfloat delta, ALint counter, ALfloat (*coeffs)[2], ALuint *delays, ALfloat (*coeffStep)[2], ALint *delayStep)
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{
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ALfloat step;
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ALuint evidx[2], azidx[2];
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ALfloat mu[3];
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ALuint lidx[4], ridx[4];
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ALuint i;
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ALfloat left, right;
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// Claculate elevation indices and interpolation factor.
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CalcEvIndices(elevation, evidx, &mu[2]);
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// Calculate azimuth indices and interpolation factor for the first
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// elevation.
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CalcAzIndices(evidx[0], azimuth, azidx, &mu[0]);
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// Calculate the first set of linear HRIR indices for left and right
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// channels.
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lidx[0] = evOffset[evidx[0]] + azidx[0];
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lidx[1] = evOffset[evidx[0]] + azidx[1];
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ridx[0] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[0]) % azCount[evidx[0]]);
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ridx[1] = evOffset[evidx[0]] + ((azCount[evidx[0]]-azidx[1]) % azCount[evidx[0]]);
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// Calculate azimuth indices and interpolation factor for the second
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// elevation.
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CalcAzIndices(evidx[1], azimuth, azidx, &mu[1]);
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// Calculate the second set of linear HRIR indices for left and right
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// channels.
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lidx[2] = evOffset[evidx[1]] + azidx[0];
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lidx[3] = evOffset[evidx[1]] + azidx[1];
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ridx[2] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[0]) % azCount[evidx[1]]);
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ridx[3] = evOffset[evidx[1]] + ((azCount[evidx[1]]-azidx[1]) % azCount[evidx[1]]);
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// Calculate the stepping parameters.
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delta = __max(0.015f * delta * Hrtf.sampleRate, 1.0f);
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step = 1.0f / delta;
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// Calculate the normalized and attenuated target HRIR coefficients using
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// linear interpolation when there is enough gain to warrant it. Zero
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// the target coefficients if gain is too low. Then calculate the
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// coefficient stepping values using the target and previous running
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// coefficients.
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if(gain > 0.0001f)
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{
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ALdouble scale = gain * (1.0/32767.0);
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for(i = 0;i < HRIR_LENGTH;i++)
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{
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left = coeffs[i][0] - (coeffStep[i][0] * counter);
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right = coeffs[i][1] - (coeffStep[i][1] * counter);
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coeffs[i][0] = lerp(lerp(Hrtf.coeffs[lidx[0]][i], Hrtf.coeffs[lidx[1]][i], mu[0]),
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lerp(Hrtf.coeffs[lidx[2]][i], Hrtf.coeffs[lidx[3]][i], mu[1]),
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mu[2]) * scale;
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coeffs[i][1] = lerp(lerp(Hrtf.coeffs[ridx[0]][i], Hrtf.coeffs[ridx[1]][i], mu[0]),
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lerp(Hrtf.coeffs[ridx[2]][i], Hrtf.coeffs[ridx[3]][i], mu[1]),
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mu[2]) * scale;
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coeffStep[i][0] = step * (coeffs[i][0] - left);
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coeffStep[i][1] = step * (coeffs[i][1] - right);
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}
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}
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else
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{
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for(i = 0;i < HRIR_LENGTH;i++)
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{
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left = coeffs[i][0] - (coeffStep[i][0] * counter);
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right = coeffs[i][1] - (coeffStep[i][1] * counter);
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coeffs[i][0] = 0.0f;
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coeffs[i][1] = 0.0f;
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coeffStep[i][0] = step * -left;
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coeffStep[i][1] = step * -right;
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}
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}
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// Calculate the HRIR delays using linear interpolation. Then calculate
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// the delay stepping values using the target and previous running
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// delays.
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left = delays[0] - (delayStep[0] * counter);
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right = delays[1] - (delayStep[1] * counter);
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delays[0] = (ALuint)(lerp(lerp(Hrtf.delays[lidx[0]], Hrtf.delays[lidx[1]], mu[0]),
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lerp(Hrtf.delays[lidx[2]], Hrtf.delays[lidx[3]], mu[1]),
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mu[2]) * 65536.0f);
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delays[1] = (ALuint)(lerp(lerp(Hrtf.delays[ridx[0]], Hrtf.delays[ridx[1]], mu[0]),
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lerp(Hrtf.delays[ridx[2]], Hrtf.delays[ridx[3]], mu[1]),
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mu[2]) * 65536.0f);
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delayStep[0] = (ALint)(step * (delays[0] - left));
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delayStep[1] = (ALint)(step * (delays[1] - right));
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// The stepping count is the number of samples necessary for the HRIR to
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// complete its transition. The mixer will only apply stepping for this
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// many samples.
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return (ALuint)delta;
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}
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ALCboolean IsHrtfCompatible(ALCdevice *device)
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{
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if(device->FmtChans == DevFmtStereo && device->Frequency == Hrtf.sampleRate)
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return ALC_TRUE;
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ERR("Incompatible HRTF format: %s %uhz (%s %uhz needed)\n",
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DevFmtChannelsString(device->FmtChans), device->Frequency,
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DevFmtChannelsString(DevFmtStereo), Hrtf.sampleRate);
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return ALC_FALSE;
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}
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void InitHrtf(void)
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{
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const char *fname;
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FILE *f = NULL;
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fname = GetConfigValue(NULL, "hrtf_tables", "");
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if(fname[0] != '\0')
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{
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f = fopen(fname, "rb");
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if(f == NULL)
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ERR("Could not open %s\n", fname);
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}
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if(f != NULL)
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{
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const ALubyte maxDelay = SRC_HISTORY_LENGTH-1;
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ALboolean failed = AL_FALSE;
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struct Hrtf newdata;
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ALchar magic[9];
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ALsizei i, j;
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if(fread(magic, 1, sizeof(magicMarker), f) != sizeof(magicMarker))
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{
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ERR("Failed to read magic marker\n");
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failed = AL_TRUE;
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}
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else if(memcmp(magic, magicMarker, sizeof(magicMarker)) != 0)
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{
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magic[8] = 0;
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ERR("Invalid magic marker: \"%s\"\n", magic);
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failed = AL_TRUE;
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}
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if(!failed)
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{
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ALushort hrirCount, hrirSize;
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ALubyte evCount;
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newdata.sampleRate = fgetc(f);
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newdata.sampleRate |= fgetc(f)<<8;
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newdata.sampleRate |= fgetc(f)<<16;
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newdata.sampleRate |= fgetc(f)<<24;
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hrirCount = fgetc(f);
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hrirCount |= fgetc(f)<<8;
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hrirSize = fgetc(f);
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hrirSize |= fgetc(f)<<8;
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evCount = fgetc(f);
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if(hrirCount != HRIR_COUNT || hrirSize != HRIR_LENGTH || evCount != ELEV_COUNT)
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{
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ERR("Unsupported value: hrirCount=%d (%d), hrirSize=%d (%d), evCount=%d (%d)\n",
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hrirCount, HRIR_COUNT, hrirSize, HRIR_LENGTH, evCount, ELEV_COUNT);
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failed = AL_TRUE;
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}
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}
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if(!failed)
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{
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for(i = 0;i < HRIR_COUNT;i++)
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{
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ALushort offset;
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offset = fgetc(f);
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offset |= fgetc(f)<<8;
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if(offset != evOffset[i])
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{
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ERR("Unsupported evOffset[%d] value: %d (%d)\n", i, offset, evOffset[i]);
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failed = AL_TRUE;
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}
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}
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}
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if(!failed)
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{
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for(i = 0;i < HRIR_COUNT;i++)
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{
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for(j = 0;j < HRIR_LENGTH;j++)
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{
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ALshort coeff;
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coeff = fgetc(f);
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coeff |= fgetc(f)<<8;
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newdata.coeffs[i][j] = coeff;
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}
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}
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for(i = 0;i < HRIR_COUNT;i++)
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{
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ALubyte delay;
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delay = fgetc(f);
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newdata.delays[i] = delay;
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if(delay > maxDelay)
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{
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ERR("Invalid delay[%d]: %d (%d)\n", i, delay, maxDelay);
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failed = AL_TRUE;
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}
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}
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if(feof(f))
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{
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ERR("Premature end of data\n");
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failed = AL_TRUE;
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}
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}
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fclose(f);
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f = NULL;
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if(!failed)
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Hrtf = newdata;
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else
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ERR("Failed to load %s\n", fname);
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}
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}
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