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/*
Copyright (C) 2000-2007 Paul Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __ardour_gtk_log_meter_h__
#define __ardour_gtk_log_meter_h__
#include "ardour/dB.h"
#if 1
static inline float
_log_meter (float power, double lower_db, double upper_db, double non_linearity)
{
return (power < lower_db ? 0.0 : pow((power-lower_db)/(upper_db-lower_db), non_linearity));
}
static inline float
alt_log_meter (float power)
{
return _log_meter (power, -192.0, 0.0, 8.0);
}
#endif
/* prototypes - avoid compiler warning */
static inline float log_meter (float db);
static inline float meter_deflect_ppm (float);
static inline float meter_deflect_din (float);
static inline float meter_deflect_nordic (float);
static inline float meter_deflect_vu (float);
static inline float meter_deflect_k (float, float);
static inline float
log_meter (float db)
{
float def = 0.0f; /* Meter deflection %age */
if (db < -70.0f) {
def = 0.0f;
} else if (db < -60.0f) {
def = (db + 70.0f) * 0.25f;
} else if (db < -50.0f) {
def = (db + 60.0f) * 0.5f + 2.5f;
} else if (db < -40.0f) {
def = (db + 50.0f) * 0.75f + 7.5f;
} else if (db < -30.0f) {
def = (db + 40.0f) * 1.5f + 15.0f;
} else if (db < -20.0f) {
def = (db + 30.0f) * 2.0f + 30.0f;
} else if (db < 6.0f) {
def = (db + 20.0f) * 2.5f + 50.0f;
} else {
def = 115.0f;
}
/* 115 is the deflection %age that would be
when db=6.0. this is an arbitrary
endpoint for our scaling.
*/
return def/115.0f;
}
static inline float
log_meter0dB (float db)
{
float def = 0.0f; /* Meter deflection %age */
if (db < -70.0f) {
def = 0.0f;
} else if (db < -60.0f) {
def = (db + 70.0f) * 0.25f;
} else if (db < -50.0f) {
def = (db + 60.0f) * 0.5f + 2.5f;
} else if (db < -40.0f) {
def = (db + 50.0f) * 0.75f + 7.5f;
} else if (db < -30.0f) {
def = (db + 40.0f) * 1.5f + 15.0f;
} else if (db < -20.0f) {
def = (db + 30.0f) * 2.0f + 30.0f;
} else if (db < 0.0f) {
def = (db + 20.0f) * 2.5f + 50.0f;
} else {
def = 100.0f;
}
return def/100.0f;
}
static inline float
meter_deflect_ppm (float db)
{
if (db < -30) {
// 2.258 == ((-30 + 32.0)/ 28.0) / 10^(-30 / 20);
return (dB_to_coefficient(db) * 2.258769757f);
} else {
const float rv = (db + 32.0f) / 28.0f;
if (rv < 1.0) {
return rv;
} else {
return 1.0;
}
}
}
static inline float
meter_deflect_din (float db)
{
float rv = dB_to_coefficient(db);
rv = sqrtf (sqrtf (2.3676f * rv)) - 0.1803f;
if (rv >= 1.0) {
return 1.0;
} else {
return (rv > 0 ? rv : 0.0);
}
}
static inline float
meter_deflect_nordic (float db)
{
if (db < -60) {
return 0.0;
} else {
const float rv = (db + 60.0f) / 54.0f;
if (rv < 1.0) {
return rv;
} else {
return 1.0;
}
}
}
static inline float
meter_deflect_vu (float db)
{
const float rv = 6.77165f * dB_to_coefficient(db);
if (rv > 1.0) return 1.0;
return rv;
}
static inline float
meter_deflect_k (float db, float krange)
{
db+=krange;
if (db < -40.0f) {
return (dB_to_coefficient(db) * 500.0f / (krange + 45.0f));
} else {
const float rv = (db + 45.0f) / (krange + 45.0f);
if (rv < 1.0) {
return rv;
} else {
return 1.0;
}
}
}
#endif /* __ardour_gtk_log_meter_h__ */
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