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livetrax/libs/ardour/gain_control.cc

150 lines
4.2 KiB
C++

/*
Copyright (C) 2006-2016 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.
*/
#include <cmath>
#include "pbd/convert.h"
#include "pbd/strsplit.h"
#include "ardour/dB.h"
#include "ardour/gain_control.h"
#include "ardour/session.h"
#include "ardour/vca.h"
#include "ardour/vca_manager.h"
#include "pbd/i18n.h"
using namespace ARDOUR;
using namespace std;
GainControl::GainControl (Session& session, const Evoral::Parameter &param, boost::shared_ptr<AutomationList> al)
: SlavableAutomationControl (session, param, ParameterDescriptor(param),
al ? al : boost::shared_ptr<AutomationList> (new AutomationList (param)),
param.type() == GainAutomation ? X_("gaincontrol") : X_("trimcontrol"),
Controllable::GainLike)
{
alist()->reset_default (1.0);
lower_db = accurate_coefficient_to_dB (_desc.lower);
range_db = accurate_coefficient_to_dB (_desc.upper) - lower_db;
}
double
GainControl::internal_to_interface (double v) const
{
if (_desc.type == GainAutomation) {
return gain_to_slider_position (v);
} else {
return (accurate_coefficient_to_dB (v) - lower_db) / range_db;
}
}
double
GainControl::interface_to_internal (double v) const
{
if (_desc.type == GainAutomation) {
return slider_position_to_gain (v);
} else {
return dB_to_coefficient (lower_db + v * range_db);
}
}
double
GainControl::internal_to_user (double v) const
{
return accurate_coefficient_to_dB (v);
}
double
GainControl::user_to_internal (double u) const
{
return dB_to_coefficient (u);
}
std::string
GainControl::get_user_string () const
{
char theBuf[32]; sprintf( theBuf, _("%3.1f dB"), accurate_coefficient_to_dB (get_value()));
return std::string(theBuf);
}
void
GainControl::inc_gain (gain_t factor)
{
/* To be used ONLY when doing group-relative gain adjustment, from
* ControlGroup::set_group_values().
*/
const float desired_gain = user_double();
if (fabsf (desired_gain) < GAIN_COEFF_SMALL) {
// really?! what's the idea here?
actually_set_value (0.000001f + (0.000001f * factor), Controllable::ForGroup);
} else {
actually_set_value (desired_gain + (desired_gain * factor), Controllable::ForGroup);
}
}
void
GainControl::recompute_masters_ratios (double val)
{
/* Master WRITE lock must be held */
/* V' is the new gain value for this
Mv(n) is the return value of ::get_value() for the n-th master
Mr(n) is the return value of ::ratio() for the n-th master record
the slave should return V' on the next call to ::get_value().
but the value is determined by the masters, so we know:
V' = (Mv(1) * Mr(1)) * (Mv(2) * Mr(2)) * ... * (Mv(n) * Mr(n))
hence:
Mr(1) * Mr(2) * ... * (Mr(n) = V' / (Mv(1) * Mv(2) * ... * Mv(n))
if we make all ratios equal (i.e. each master contributes the same
fraction of its own gain level to make the final slave gain), then we
have:
pow (Mr(n), n) = V' / (Mv(1) * Mv(2) * ... * Mv(n))
which gives
Mr(n) = pow ((V' / (Mv(1) * Mv(2) * ... * Mv(n))), 1/n)
Mr(n) is the new ratio number for the slaves
*/
const double nmasters = _masters.size();
double masters_total_gain_coefficient = 1.0;
for (Masters::iterator mr = _masters.begin(); mr != _masters.end(); ++mr) {
masters_total_gain_coefficient *= mr->second.master()->get_value();
}
const double new_universal_ratio = pow ((val / masters_total_gain_coefficient), (1.0/nmasters));
for (Masters::iterator mr = _masters.begin(); mr != _masters.end(); ++mr) {
mr->second.reset_ratio (new_universal_ratio);
}
}