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openal-soft/Alc/panning.c
Chris Robinson 611bd0b2d3 Add a method to calculate gains given a sound point and its half-width, and use it for reverb 
The half-width ranges from 0 to pi, and essentially specifies the coverage area
around the listener. At 0, it's an infinitely small point sound and behaves
like a usual panning sound. At pi/2 it covers half the area, and at pi it
covers the whole area.
2012-04-28 08:21:53 -07:00

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/**
* OpenAL cross platform audio library
* Copyright (C) 1999-2010 by authors.
* 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 <math.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
#include "alMain.h"
#include "AL/al.h"
#include "AL/alc.h"
#include "alu.h"
static void SetSpeakerArrangement(const char *name, ALfloat SpeakerAngle[MAXCHANNELS],
enum Channel Speaker2Chan[MAXCHANNELS], ALint chans)
{
char *confkey, *next;
char *layout_str;
char *sep, *end;
enum Channel val;
const char *str;
int i;
if(!ConfigValueStr(NULL, name, &str) && !ConfigValueStr(NULL, "layout", &str))
return;
layout_str = strdup(str);
next = confkey = layout_str;
while(next && *next)
{
confkey = next;
next = strchr(confkey, ',');
if(next)
{
*next = 0;
do {
next++;
} while(isspace(*next) || *next == ',');
}
sep = strchr(confkey, '=');
if(!sep || confkey == sep)
{
ERR("Malformed speaker key: %s\n", confkey);
continue;
}
end = sep - 1;
while(isspace(*end) && end != confkey)
end--;
*(++end) = 0;
if(strcmp(confkey, "fl") == 0 || strcmp(confkey, "front-left") == 0)
val = FRONT_LEFT;
else if(strcmp(confkey, "fr") == 0 || strcmp(confkey, "front-right") == 0)
val = FRONT_RIGHT;
else if(strcmp(confkey, "fc") == 0 || strcmp(confkey, "front-center") == 0)
val = FRONT_CENTER;
else if(strcmp(confkey, "bl") == 0 || strcmp(confkey, "back-left") == 0)
val = BACK_LEFT;
else if(strcmp(confkey, "br") == 0 || strcmp(confkey, "back-right") == 0)
val = BACK_RIGHT;
else if(strcmp(confkey, "bc") == 0 || strcmp(confkey, "back-center") == 0)
val = BACK_CENTER;
else if(strcmp(confkey, "sl") == 0 || strcmp(confkey, "side-left") == 0)
val = SIDE_LEFT;
else if(strcmp(confkey, "sr") == 0 || strcmp(confkey, "side-right") == 0)
val = SIDE_RIGHT;
else
{
ERR("Unknown speaker for %s: \"%s\"\n", name, confkey);
continue;
}
*(sep++) = 0;
while(isspace(*sep))
sep++;
for(i = 0;i < chans;i++)
{
if(Speaker2Chan[i] == val)
{
long angle = strtol(sep, NULL, 10);
if(angle >= -180 && angle <= 180)
SpeakerAngle[i] = angle * F_PI/180.0f;
else
ERR("Invalid angle for speaker \"%s\": %ld\n", confkey, angle);
break;
}
}
}
free(layout_str);
layout_str = NULL;
for(i = 0;i < chans;i++)
{
int min = i;
int i2;
for(i2 = i+1;i2 < chans;i2++)
{
if(SpeakerAngle[i2] < SpeakerAngle[min])
min = i2;
}
if(min != i)
{
ALfloat tmpf;
enum Channel tmpc;
tmpf = SpeakerAngle[i];
SpeakerAngle[i] = SpeakerAngle[min];
SpeakerAngle[min] = tmpf;
tmpc = Speaker2Chan[i];
Speaker2Chan[i] = Speaker2Chan[min];
Speaker2Chan[min] = tmpc;
}
}
}
static ALfloat aluLUTpos2Angle(ALint pos)
{
if(pos < QUADRANT_NUM)
return aluAtan((ALfloat)pos / (ALfloat)(QUADRANT_NUM - pos));
if(pos < 2 * QUADRANT_NUM)
return F_PI_2 + aluAtan((ALfloat)(pos - QUADRANT_NUM) / (ALfloat)(2 * QUADRANT_NUM - pos));
if(pos < 3 * QUADRANT_NUM)
return aluAtan((ALfloat)(pos - 2 * QUADRANT_NUM) / (ALfloat)(3 * QUADRANT_NUM - pos)) - F_PI;
return aluAtan((ALfloat)(pos - 3 * QUADRANT_NUM) / (ALfloat)(4 * QUADRANT_NUM - pos)) - F_PI_2;
}
ALint aluCart2LUTpos(ALfloat im, ALfloat re)
{
ALint pos = 0;
ALfloat denom = aluFabs(im) + aluFabs(re);
if(denom > 0.0f)
pos = (ALint)(QUADRANT_NUM*aluFabs(im) / denom + 0.5);
if(re < 0.0f)
pos = 2 * QUADRANT_NUM - pos;
if(im < 0.0f)
pos = LUT_NUM - pos;
return pos%LUT_NUM;
}
/**
* ComputeAngleGains
*
* Sets channel gains based on a given source's angle and its half-width. The
* angle and hwidth parameters are in radians.
*/
ALvoid ComputeAngleGains(const ALCdevice *device, ALfloat angle, ALfloat hwidth, ALfloat ingain, ALfloat *gains)
{
const enum Channel *Speaker2Chan = device->Speaker2Chan;
const ALfloat *SpeakerAngle = device->SpeakerAngle;
ALfloat tmpgains[MAXCHANNELS] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
ALboolean inverted = AL_FALSE;
ALfloat langle, rangle;
ALfloat a;
ALuint i;
/* Some easy special-cases first... */
if(device->NumChan == 1 || hwidth >= F_PI)
{
/* Full coverage for all speakers. */
for(i = 0;i < device->NumChan;i++)
{
enum Channel chan = Speaker2Chan[i];
gains[chan] = ingain;
}
return;
}
if(hwidth <= 0.0f)
{
/* Infinitismally small sound point. */
for(i = 0;i < device->NumChan-1;i++)
{
if(angle >= SpeakerAngle[i] && angle < SpeakerAngle[i+1])
{
/* Sound is between speaker i and i+1 */
a = (angle-SpeakerAngle[i]) /
(SpeakerAngle[i+1]-SpeakerAngle[i]);
gains[Speaker2Chan[i]] = aluSqrt(1.0f-a) * ingain;
gains[Speaker2Chan[i+1]] = aluSqrt( a) * ingain;
return;
}
}
/* Sound is between last and first speakers */
if(angle < SpeakerAngle[0])
angle += F_PI*2.0f;
a = (angle-SpeakerAngle[i]) /
(F_PI*2.0f + SpeakerAngle[0]-SpeakerAngle[i]);
gains[Speaker2Chan[i]] = aluSqrt(1.0f-a) * ingain;
gains[Speaker2Chan[0]] = aluSqrt( a) * ingain;
return;
}
langle = angle - hwidth;
rangle = angle + hwidth;
if(langle < -F_PI)
langle += F_PI*2.0f;
if(rangle > F_PI)
rangle -= F_PI*2.0f;
if(langle > rangle)
{
/* langle and rangle are swapped to keep the langle<rangle assumption
* true, which keeps the following calculations sane. This inverts the
* results, so speakers within the original field end up as 0 and
* outside end up as 1. A fixup is done afterward to make sure the
* results are as expected. */
ALfloat tmp = rangle;
rangle = langle;
langle = tmp;
inverted = AL_TRUE;
}
/* First speaker */
i = 0;
{
ALuint last = device->NumChan-1;
if(SpeakerAngle[i] >= langle && SpeakerAngle[i] <= rangle)
tmpgains[Speaker2Chan[i]] = 1.0f;
else if(SpeakerAngle[i] < langle && SpeakerAngle[i+1] > langle)
{
a = (langle-SpeakerAngle[i]) /
(SpeakerAngle[i+1]-SpeakerAngle[i]);
tmpgains[Speaker2Chan[i]] = 1.0f - a;
}
else if(SpeakerAngle[i] > rangle)
{
a = (F_PI*2.0f + rangle-SpeakerAngle[last]) /
(F_PI*2.0f + SpeakerAngle[i]-SpeakerAngle[last]);
tmpgains[Speaker2Chan[i]] = a;
}
else if(rangle > SpeakerAngle[last])
{
a = (rangle-SpeakerAngle[last]) /
(F_PI*2.0f + SpeakerAngle[i]-SpeakerAngle[last]);
tmpgains[Speaker2Chan[i]] = a;
}
}
for(i = 1;i < device->NumChan-1;i++)
{
if(SpeakerAngle[i] >= langle && SpeakerAngle[i] <= rangle)
tmpgains[Speaker2Chan[i]] = 1.0f;
else if(SpeakerAngle[i] < langle && SpeakerAngle[i+1] > langle)
{
a = (langle-SpeakerAngle[i]) /
(SpeakerAngle[i+1]-SpeakerAngle[i]);
tmpgains[Speaker2Chan[i]] = 1.0f - a;
}
else if(SpeakerAngle[i] > rangle && SpeakerAngle[i-1] < rangle)
{
a = (rangle-SpeakerAngle[i-1]) /
(SpeakerAngle[i]-SpeakerAngle[i-1]);
tmpgains[Speaker2Chan[i]] = a;
}
}
/* Last speaker */
i = device->NumChan-1;
{
if(SpeakerAngle[i] >= langle && SpeakerAngle[i] <= rangle)
tmpgains[Speaker2Chan[i]] = 1.0f;
else if(SpeakerAngle[i] > rangle && SpeakerAngle[i-1] < rangle)
{
a = (rangle-SpeakerAngle[i-1]) /
(SpeakerAngle[i]-SpeakerAngle[i-1]);
tmpgains[Speaker2Chan[i]] = a;
}
else if(SpeakerAngle[i] < langle)
{
ALfloat nextangle = SpeakerAngle[0] + F_PI*2.0f;
a = (langle-SpeakerAngle[i]) /
(nextangle-SpeakerAngle[i]);
tmpgains[Speaker2Chan[i]] = 1.0f - a;
}
else if(SpeakerAngle[0] > langle)
{
a = (langle-SpeakerAngle[i] - F_PI*2.0f) /
(SpeakerAngle[0]-SpeakerAngle[i] - F_PI*2.0f);
tmpgains[Speaker2Chan[i]] = 1.0f - a;
}
}
if(inverted)
{
for(i = 0;i < device->NumChan;i++)
{
enum Channel chan = device->Speaker2Chan[i];
gains[chan] = aluSqrt(1.0f - tmpgains[chan]) * ingain;
}
}
else
{
for(i = 0;i < device->NumChan;i++)
{
enum Channel chan = device->Speaker2Chan[i];
gains[chan] = aluSqrt(tmpgains[chan]) * ingain;
}
}
}
ALvoid aluInitPanning(ALCdevice *Device)
{
const char *layoutname = NULL;
enum Channel *Speaker2Chan;
ALfloat *SpeakerAngle;
ALfloat Alpha, Theta;
ALint pos;
ALuint s;
Speaker2Chan = Device->Speaker2Chan;
SpeakerAngle = Device->SpeakerAngle;
switch(Device->FmtChans)
{
case DevFmtMono:
Device->NumChan = 1;
Speaker2Chan[0] = FRONT_CENTER;
SpeakerAngle[0] = F_PI/180.0f * 0.0f;
layoutname = NULL;
break;
case DevFmtStereo:
Device->NumChan = 2;
Speaker2Chan[0] = FRONT_LEFT;
Speaker2Chan[1] = FRONT_RIGHT;
SpeakerAngle[0] = F_PI/180.0f * -90.0f;
SpeakerAngle[1] = F_PI/180.0f * 90.0f;
layoutname = "layout_stereo";
break;
case DevFmtQuad:
Device->NumChan = 4;
Speaker2Chan[0] = BACK_LEFT;
Speaker2Chan[1] = FRONT_LEFT;
Speaker2Chan[2] = FRONT_RIGHT;
Speaker2Chan[3] = BACK_RIGHT;
SpeakerAngle[0] = F_PI/180.0f * -135.0f;
SpeakerAngle[1] = F_PI/180.0f * -45.0f;
SpeakerAngle[2] = F_PI/180.0f * 45.0f;
SpeakerAngle[3] = F_PI/180.0f * 135.0f;
layoutname = "layout_quad";
break;
case DevFmtX51:
Device->NumChan = 5;
Speaker2Chan[0] = BACK_LEFT;
Speaker2Chan[1] = FRONT_LEFT;
Speaker2Chan[2] = FRONT_CENTER;
Speaker2Chan[3] = FRONT_RIGHT;
Speaker2Chan[4] = BACK_RIGHT;
SpeakerAngle[0] = F_PI/180.0f * -110.0f;
SpeakerAngle[1] = F_PI/180.0f * -30.0f;
SpeakerAngle[2] = F_PI/180.0f * 0.0f;
SpeakerAngle[3] = F_PI/180.0f * 30.0f;
SpeakerAngle[4] = F_PI/180.0f * 110.0f;
layoutname = "layout_surround51";
break;
case DevFmtX51Side:
Device->NumChan = 5;
Speaker2Chan[0] = SIDE_LEFT;
Speaker2Chan[1] = FRONT_LEFT;
Speaker2Chan[2] = FRONT_CENTER;
Speaker2Chan[3] = FRONT_RIGHT;
Speaker2Chan[4] = SIDE_RIGHT;
SpeakerAngle[0] = F_PI/180.0f * -90.0f;
SpeakerAngle[1] = F_PI/180.0f * -30.0f;
SpeakerAngle[2] = F_PI/180.0f * 0.0f;
SpeakerAngle[3] = F_PI/180.0f * 30.0f;
SpeakerAngle[4] = F_PI/180.0f * 90.0f;
layoutname = "layout_side51";
break;
case DevFmtX61:
Device->NumChan = 6;
Speaker2Chan[0] = SIDE_LEFT;
Speaker2Chan[1] = FRONT_LEFT;
Speaker2Chan[2] = FRONT_CENTER;
Speaker2Chan[3] = FRONT_RIGHT;
Speaker2Chan[4] = SIDE_RIGHT;
Speaker2Chan[5] = BACK_CENTER;
SpeakerAngle[0] = F_PI/180.0f * -90.0f;
SpeakerAngle[1] = F_PI/180.0f * -30.0f;
SpeakerAngle[2] = F_PI/180.0f * 0.0f;
SpeakerAngle[3] = F_PI/180.0f * 30.0f;
SpeakerAngle[4] = F_PI/180.0f * 90.0f;
SpeakerAngle[5] = F_PI/180.0f * 180.0f;
layoutname = "layout_surround61";
break;
case DevFmtX71:
Device->NumChan = 7;
Speaker2Chan[0] = BACK_LEFT;
Speaker2Chan[1] = SIDE_LEFT;
Speaker2Chan[2] = FRONT_LEFT;
Speaker2Chan[3] = FRONT_CENTER;
Speaker2Chan[4] = FRONT_RIGHT;
Speaker2Chan[5] = SIDE_RIGHT;
Speaker2Chan[6] = BACK_RIGHT;
SpeakerAngle[0] = F_PI/180.0f * -150.0f;
SpeakerAngle[1] = F_PI/180.0f * -90.0f;
SpeakerAngle[2] = F_PI/180.0f * -30.0f;
SpeakerAngle[3] = F_PI/180.0f * 0.0f;
SpeakerAngle[4] = F_PI/180.0f * 30.0f;
SpeakerAngle[5] = F_PI/180.0f * 90.0f;
SpeakerAngle[6] = F_PI/180.0f * 150.0f;
layoutname = "layout_surround71";
break;
}
if(layoutname && Device->Type != Loopback)
SetSpeakerArrangement(layoutname, SpeakerAngle, Speaker2Chan, Device->NumChan);
for(pos = 0; pos < LUT_NUM; pos++)
{
ALfloat *PanningLUT = Device->PanningLUT[pos];
/* clear all values */
for(s = 0; s < MAXCHANNELS; s++)
PanningLUT[s] = 0.0f;
if(Device->NumChan == 1)
{
PanningLUT[Speaker2Chan[0]] = 1.0f;
continue;
}
/* source angle */
Theta = aluLUTpos2Angle(pos);
/* set panning values */
for(s = 0; s < Device->NumChan - 1; s++)
{
if(Theta >= SpeakerAngle[s] && Theta < SpeakerAngle[s+1])
{
/* source between speaker s and speaker s+1 */
Alpha = (Theta-SpeakerAngle[s]) /
(SpeakerAngle[s+1]-SpeakerAngle[s]);
PanningLUT[Speaker2Chan[s]] = aluSqrt(1.0f-Alpha);
PanningLUT[Speaker2Chan[s+1]] = aluSqrt( Alpha);
break;
}
}
if(s == Device->NumChan - 1)
{
/* source between last and first speaker */
if(Theta < SpeakerAngle[0])
Theta += F_PI*2.0f;
Alpha = (Theta-SpeakerAngle[s]) /
(F_PI*2.0f + SpeakerAngle[0]-SpeakerAngle[s]);
PanningLUT[Speaker2Chan[s]] = aluSqrt(1.0f-Alpha);
PanningLUT[Speaker2Chan[0]] = aluSqrt( Alpha);
}
}
}
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