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/* FluidSynth - A Software Synthesizer
*
* Copyright (C) 2003 Peter Hanappe and others.
*
* 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
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307, USA
*/
#include "conv.h"
namespace FluidS {
/* conversion tables */
static float fluid_cb2amp_tab[FLUID_CB_AMP_SIZE];
static float fluid_atten2amp_tab[FLUID_ATTEN_AMP_SIZE];
static float fluid_concave_tab[128];
static float fluid_convex_tab[128];
static float fluid_pan_tab[FLUID_PAN_SIZE];
/*
* void fluid_synth_init
*
* Does all the initialization for this module.
*/
void fluid_conversion_config()
{
/* centibels to amplitude conversion
* Note: SF2.01 section 8.1.3: Initial attenuation range is
* between 0 and 144 dB. Therefore a negative attenuation is
* not allowed.
*/
for (int i = 0; i < FLUID_CB_AMP_SIZE; i++)
fluid_cb2amp_tab[i] = (float) pow(10.0, (double) i / -200.0);
/* NOTE: EMU8k and EMU10k devices don't conform to the SoundFont
* specification in regards to volume attenuation. The below calculation
* is an approx. equation for generating a table equivelant to the
* cb_to_amp_table[] in tables.c of the TiMidity++ source, which I'm told
* was generated from device testing. By the spec this should be centibels.
*/
for (int i = 0; i < FLUID_ATTEN_AMP_SIZE; i++)
fluid_atten2amp_tab[i] = (float) pow(10.0, (double) i / FLUID_ATTEN_POWER_FACTOR);
/* initialize the conversion tables (see fluid_mod.c
fluid_mod_get_value cases 4 and 8) */
/* concave unipolar positive transform curve */
fluid_concave_tab[0] = 0.0;
fluid_concave_tab[127] = 1.0;
/* convex unipolar positive transform curve */
fluid_convex_tab[0] = 0;
fluid_convex_tab[127] = 1.0;
/* There seems to be an error in the specs. The equations are
implemented according to the pictures on SF2.01 page 73. */
for (int i = 1; i < 127; i++) {
double x = -20.0 / 96.0 * log((i * i) / (127.0 * 127.0)) / log(10.0);
fluid_convex_tab[i] = (float) (1.0 - x);
fluid_concave_tab[127 - i] = (float) x;
}
/* initialize the pan conversion table */
double x = M_PI / 2.0 / (FLUID_PAN_SIZE - 1.0);
for (int i = 0; i < FLUID_PAN_SIZE; i++)
fluid_pan_tab[i] = (float) sin(i * x);
}
/*
* fluid_cb2amp
*
* in: a value between 0 and 960, 0 is no attenuation
* out: a value between 1 and 0
*/
float fluid_cb2amp(float cb)
{
/*
* cb: an attenuation in 'centibels' (1/10 dB)
* SF2.01 page 49 # 48 limits it to 144 dB.
* 96 dB is reasonable for 16 bit systems, 144 would make sense for 24 bit.
*/
/* minimum attenuation: 0 dB */
if (cb < 0)
return 1.0;
if (cb >= FLUID_CB_AMP_SIZE)
return 0.0;
return fluid_cb2amp_tab[(int) cb];
}
/*
* fluid_atten2amp
*
* in: a value between 0 and 1440, 0 is no attenuation
* out: a value between 1 and 0
*
* Note: Volume attenuation is supposed to be centibels but EMU8k/10k don't
* follow this. Thats the reason for separate fluid_cb2amp and fluid_atten2amp.
*/
float fluid_atten2amp(float atten)
{
if (atten < 0)
return 1.0;
else if (atten >= FLUID_ATTEN_AMP_SIZE)
return 0.0;
else
return fluid_atten2amp_tab[(int) atten];
}
/*
* fluid_tc2sec_delay
*/
float fluid_tc2sec_delay(float tc)
{
/* SF2.01 section 8.1.2 items 21, 23, 25, 33
* SF2.01 section 8.1.3 items 21, 23, 25, 33
*
* The most negative number indicates a delay of 0. Range is limited
* from -12000 to 5000
*/
if (tc <= -32768.0f)
return (float) 0.0f;
if (tc < -12000.)
tc = (float) -12000.0f;
if (tc > 5000.0f)
tc = (float) 5000.0f;
return (float) pow(2.0, (double) tc / 1200.0);
}
/*
* fluid_tc2sec_attack
*/
float fluid_tc2sec_attack(float tc)
{
/* SF2.01 section 8.1.2 items 26, 34
* SF2.01 section 8.1.3 items 26, 34
* The most negative number indicates a delay of 0
* Range is limited from -12000 to 8000 */
if (tc<=-32768.)
return (float) 0.0;
if (tc<-12000.)
tc=(float) -12000.0;
if (tc>8000.)
tc=(float) 8000.0;
return (float) pow(2.0, (double) tc / 1200.0);
}
/*
* fluid_tc2sec
*/
float fluid_tc2sec(float tc)
{
/* No range checking here! */
return (float) pow(2.0, (double) tc / 1200.0);
}
/*
* fluid_tc2sec_release
*/
float fluid_tc2sec_release(float tc)
{
/* SF2.01 section 8.1.2 items 30, 38
* SF2.01 section 8.1.3 items 30, 38
* No 'most negative number' rule here!
* Range is limited from -12000 to 8000
*/
if (tc<=-32768.)
return (float) 0.0;
if (tc<-12000.)
tc=(float) -12000.0;
if (tc>8000.)
tc=(float) 8000.0;
return (float) pow(2.0, (double) tc / 1200.0);
}
/*
* fluid_act2hz
*
* Convert from absolute cents to Hertz
*/
float fluid_act2hz(float c)
{
return (float) (8.176 * pow(2.0, (double) c / 1200.0));
}
/*
* fluid_pan
*/
float fluid_pan(float c, int left)
{
if (left)
c = -c;
if (c < -500)
return (float) 0.0;
else if (c > 500)
return (float) 1.0;
else
return fluid_pan_tab[(int) (c + 500)];
}
/*
* fluid_concave
*/
float fluid_concave(float val)
{
if (val < 0)
return 0;
else if (val > 127)
return 1;
return fluid_concave_tab[(int) val];
}
/*
* fluid_convex
*/
float fluid_convex(float val)
{
if (val < 0)
return 0;
else if (val > 127)
return 1;
return fluid_convex_tab[(int) val];
}
}
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