124 lines
3.4 KiB
C
124 lines
3.4 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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#define HRIR_COUNT 828
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static const ALubyte evCount = 19;
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static const ALushort evOffset[19] = { 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[19] = { 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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ALshort coeffs[HRIR_COUNT][HRIR_LENGTH];
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ALubyte delays[HRIR_COUNT];
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} Hrtf = {
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#include "hrtf_tables.inc"
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};
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static ALuint CalcEvIndex(ALdouble ev)
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{
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ev = (M_PI/2.0 + ev) * (evCount-1) / M_PI;
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return (ALuint)(ev+0.5);
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}
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static ALuint CalcAzIndex(ALint evidx, ALdouble az)
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{
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az = (M_PI*2.0 + az) * azCount[evidx] / (M_PI*2.0);
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return (ALuint)(az+0.5) % azCount[evidx];
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}
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void GetHrtfCoeffs(ALfloat elevation, ALfloat angle, const ALshort **left, const ALshort **right, ALuint *ldelay, ALuint *rdelay)
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{
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ALuint lidx, ridx;
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ALuint evidx, azidx;
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evidx = CalcEvIndex(elevation);
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azidx = CalcAzIndex(evidx, angle);
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lidx = evOffset[evidx] + azidx;
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ridx = evOffset[evidx] + ((azCount[evidx]-azidx) % azCount[evidx]);
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*ldelay = Hrtf.delays[lidx];
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*rdelay = Hrtf.delays[ridx];
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*left = Hrtf.coeffs[lidx];
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*right = Hrtf.coeffs[ridx];
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}
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void InitHrtf(void)
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{
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const char *str;
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FILE *f = NULL;
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str = GetConfigValue(NULL, "hrtf_tables", "");
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if(str[0] != '\0')
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{
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f = fopen(str, "rb");
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if(f == NULL)
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AL_PRINT("Could not open %s\n", str);
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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;
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ALboolean failed = AL_FALSE;
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struct HRTF newdata;
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size_t i, j;
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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 val;
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val = fgetc(f);
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val |= fgetc(f)<<8;
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newdata.coeffs[i][j] = val;
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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 val;
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val = fgetc(f);
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newdata.delays[i] = val;
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if(val > maxDelay)
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{
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AL_PRINT("Invalid delay at idx %d: %u (max: %u), in %s\n", i, val, maxDelay, str);
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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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AL_PRINT("Premature end of data while reading %s\n", str);
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failed = AL_TRUE;
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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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}
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}
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