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Use floats for the BS2B filter

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This commit is contained in:
Chris Robinson 2014-06-11 09:57:48 -07:00
parent dfded9595c
commit 4c706f59d9
2 changed files with 44 additions and 44 deletions
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68
Alc/bs2b.c
View File

@ -27,6 +27,7 @@
#include <string.h>
#include "bs2b.h"
#include "alu.h"
#ifndef M_PI
#define M_PI 3.14159265358979323846
@ -35,57 +36,56 @@
/* Set up all data. */
static void init(struct bs2b *bs2b)
{
double Fc_lo, Fc_hi;
double G_lo, G_hi;
double x;
float Fc_lo, Fc_hi;
float G_lo, G_hi;
float x;
if(bs2b->srate > 192000 || bs2b->srate < 2000)
bs2b->srate = BS2B_DEFAULT_SRATE;
bs2b->srate = clampi(bs2b->srate, 2000, 192000);
switch(bs2b->level)
{
case BS2B_LOW_CLEVEL: /* Low crossfeed level */
Fc_lo = 360.0;
Fc_hi = 501.0;
G_lo = 0.398107170553497;
G_hi = 0.205671765275719;
Fc_lo = 360.0f;
Fc_hi = 501.0f;
G_lo = 0.398107170553497f;
G_hi = 0.205671765275719f;
break;
case BS2B_MIDDLE_CLEVEL: /* Middle crossfeed level */
Fc_lo = 500.0;
Fc_hi = 711.0;
G_lo = 0.459726988530872;
G_hi = 0.228208484414988;
Fc_lo = 500.0f;
Fc_hi = 711.0f;
G_lo = 0.459726988530872f;
G_hi = 0.228208484414988f;
break;
case BS2B_HIGH_CLEVEL: /* High crossfeed level (virtual speakers are closer to itself) */
Fc_lo = 700.0;
Fc_hi = 1021.0;
G_lo = 0.530884444230988;
G_hi = 0.250105790667544;
Fc_lo = 700.0f;
Fc_hi = 1021.0f;
G_lo = 0.530884444230988f;
G_hi = 0.250105790667544f;
break;
case BS2B_LOW_ECLEVEL: /* Low easy crossfeed level */
Fc_lo = 360.0;
Fc_hi = 494.0;
G_lo = 0.316227766016838;
G_hi = 0.168236228897329;
Fc_lo = 360.0f;
Fc_hi = 494.0f;
G_lo = 0.316227766016838f;
G_hi = 0.168236228897329f;
break;
case BS2B_MIDDLE_ECLEVEL: /* Middle easy crossfeed level */
Fc_lo = 500.0;
Fc_hi = 689.0;
G_lo = 0.354813389233575;
G_hi = 0.187169483835901;
Fc_lo = 500.0f;
Fc_hi = 689.0f;
G_lo = 0.354813389233575f;
G_hi = 0.187169483835901f;
break;
default: /* High easy crossfeed level */
bs2b->level = BS2B_HIGH_ECLEVEL;
Fc_lo = 700.0;
Fc_hi = 975.0;
G_lo = 0.398107170553497;
G_hi = 0.205671765275719;
Fc_lo = 700.0f;
Fc_hi = 975.0f;
G_lo = 0.398107170553497f;
G_hi = 0.205671765275719f;
break;
} /* switch */
@ -94,16 +94,16 @@ static void init(struct bs2b *bs2b)
* $x = exp(-1 / $d);
*/
x = exp(-2.0 * M_PI * Fc_lo / bs2b->srate);
x = expf(-2.0f * F_PI * Fc_lo / bs2b->srate);
bs2b->b1_lo = x;
bs2b->a0_lo = G_lo * (1.0 - x);
bs2b->a0_lo = G_lo * (1.0f - x);
x = exp(-2.0 * M_PI * Fc_hi / bs2b->srate);
x = expf(-2.0f * F_PI * Fc_hi / bs2b->srate);
bs2b->b1_hi = x;
bs2b->a0_hi = 1.0 - G_hi * (1.0 - x);
bs2b->a0_hi = 1.0f - G_hi * (1.0f - x);
bs2b->a1_hi = -x;
bs2b->gain = 1.0f / (float)(1.0 - G_hi + G_lo);
bs2b->gain = 1.0f / (1.0f - G_hi + G_lo);
} /* init */
/* Exported functions.

20
OpenAL32/Include/bs2b.h
View File

@ -51,13 +51,13 @@ struct bs2b {
int srate; /* Sample rate (Hz) */
/* Lowpass IIR filter coefficients */
double a0_lo;
double b1_lo;
float a0_lo;
float b1_lo;
/* Highboost IIR filter coefficients */
double a0_hi;
double a1_hi;
double b1_hi;
float a0_hi;
float a1_hi;
float b1_hi;
/* Global gain against overloading */
float gain;
@ -66,9 +66,9 @@ struct bs2b {
* [0] - first channel, [1] - second channel
*/
struct t_last_sample {
double asis[2];
double lo[2];
double hi[2];
float asis[2];
float lo[2];
float hi[2];
} last_sample;
};
@ -120,8 +120,8 @@ inline void bs2b_cross_feed(struct bs2b *bs2b, float *restrict samples)
bs2b->last_sample.asis[1] = samples[1];
/* Crossfeed */
samples[0] = (float)(bs2b->last_sample.hi[0] + bs2b->last_sample.lo[1]);
samples[1] = (float)(bs2b->last_sample.hi[1] + bs2b->last_sample.lo[0]);
samples[0] = bs2b->last_sample.hi[0] + bs2b->last_sample.lo[1];
samples[1] = bs2b->last_sample.hi[1] + bs2b->last_sample.lo[0];
/* Bass boost cause allpass attenuation */
samples[0] *= bs2b->gain;