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/*
ampmidid.cpp
Copyright (C) 2006 Michael Gogins
This file is part of Csound.
The Csound Library is free software; you can redistribute it
and/or modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Csound 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with Csound; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include <cmath>
#include "OpcodeBase.hpp"
using namespace csound;
/**
* Musically map MIDI velocity to peak amplitude
* within a specified dynamic range in decibels:
* a = (m * v + b) ^ 2
* where a = amplitude,
* v = MIDI velocity,
* r = 10 ^ (R / 20),
* b = 127 / (126 * sqrt( r )) - 1 / 126,
* m = (1 - b) / 127,
* and R = specified dynamic range in decibels.
* See Roger Dannenberg, "The Interpretation of MIDI Velocity,"
* in Georg Essl and Ichiro Fujinaga (Eds.), Proceedings of the
* 2006 International Computer Music Conference,
* November 6-11, 2006 (San Francisco:
* The International Computer Music Association), pp. 193-196.
*/
class KAMPMIDID : public OpcodeBase<KAMPMIDID> {
public:
// Outputs.
MYFLT *kamplitude;
// Inputs.
MYFLT *kvelocity;
MYFLT *irdb;
MYFLT *iuse0dbfs;
// State.
MYFLT ir;
MYFLT im;
MYFLT ib;
MYFLT onedrms;
MYFLT dbfs;
KAMPMIDID()
: kamplitude(0), kvelocity(0), irdb(0), iuse0dbfs(0), ir(0), im(0), ib(0),
onedrms(0), dbfs(1) {}
int init(CSOUND *csound) {
// Convert RMS power to amplitude (assuming a sinusoidal signal).
onedrms = MYFLT(1.0) / MYFLT(0.707);
// Convert dynamic range in decibels to RMS dynamic range.
ir = std::pow(MYFLT(10.0), *irdb / MYFLT(20.0));
// Solve for coefficients of the linear conversion function given
// RMS dynamic range.
ib = MYFLT(127.0) / (MYFLT(126.0) * std::sqrt(ir)) -
MYFLT(1.0) / MYFLT(126.0);
im = (MYFLT(1.0) - ib) / MYFLT(127.0);
if (*iuse0dbfs == FL(0.0)) {
dbfs = csound->Get0dBFS(csound);
} else {
dbfs = *iuse0dbfs;
}
return OK;
}
int kontrol(CSOUND *csound) {
IGN(csound);
*kamplitude =
dbfs * std::pow((*kvelocity * im) + ib, MYFLT(2.0)) * onedrms;
return OK;
}
};
class IAMPMIDID : public OpcodeBase<IAMPMIDID> {
public:
// Outputs.
MYFLT *iamplitude;
// Inputs.
MYFLT *ivelocity;
MYFLT *irdb;
MYFLT *iuse0dbfs;
// State.
MYFLT ir;
MYFLT im;
MYFLT ib;
MYFLT onedrms;
MYFLT dbfs;
IAMPMIDID()
: iamplitude(0), ivelocity(0), irdb(0), iuse0dbfs(0), ir(0), im(0), ib(0),
onedrms(0), dbfs(1) {}
int init(CSOUND *csound) {
// Convert RMS power to amplitude (assuming a sinusoidal signal).
onedrms = MYFLT(1.0) / MYFLT(0.707);
// Convert dynamic range in decibels to RMS dynamic range.
ir = std::pow(MYFLT(10.0), *irdb / MYFLT(20.0));
// Solve for coefficients of the linear conversion function given
// RMS dynamic range.
ib = MYFLT(127.0) / (MYFLT(126.0) * std::sqrt(ir)) -
MYFLT(1.0) / MYFLT(126.0);
im = (MYFLT(1.0) - ib) / MYFLT(127.0);
if (*iuse0dbfs == FL(0.0)) {
dbfs = csound->Get0dBFS(csound);
} else {
dbfs = *iuse0dbfs;
}
*iamplitude =
dbfs * std::pow((*ivelocity * im) + ib, MYFLT(2.0)) * onedrms;
return OK;
}
int noteoff(CSOUND *) {
return OK;
}
};
/**
* Maps an input MIDI velocity number to an output gain factor with a maximum
* value of 1, modifying the output gain by a dynamic range and a shaping
* exponent. The minimum output gain is 1 minus the dynamic
* range. A shaping exponent of 1 is a linear response; increasing the
* exponent produces an increasingly depressed knee in the gain response
* curve. This opcode was suggested by Mauro Giubileo, and its behavior
* can be seen at https://www.desmos.com/calculator/fvxupgp4ef.
*/
class AMPMIDICURVE : public OpcodeBase<AMPMIDICURVE> {
public:
MYFLT *k_gain;
MYFLT *k_midi_velocity;
MYFLT *k_dynamic_range;
MYFLT *k_exponent;
int init(CSOUND *csound) {
*k_gain = *k_dynamic_range * std::pow(*k_midi_velocity / FL(127.), *k_exponent) + FL(1.) - *k_dynamic_range;
return OK;
}
int kontrol(CSOUND *csound) {
*k_gain = *k_dynamic_range * std::pow(*k_midi_velocity / FL(127.), *k_exponent) + FL(1.) - *k_dynamic_range;
return OK;
}
};
extern "C" {
PUBLIC int csoundModuleInit_ampmidid(CSOUND *csound) {
int status = csound->AppendOpcode(
csound, (char *)"ampmidid.k", sizeof(KAMPMIDID), 0, 3, (char *)"k",
(char *)"kio",
(int (*)(CSOUND *, void *))KAMPMIDID::init_,
(int (*)(CSOUND *, void *))KAMPMIDID::kontrol_,
(int (*)(CSOUND *, void *))0);
status |= csound->AppendOpcode(
csound, (char *)"ampmidid.i", sizeof(IAMPMIDID), 0, 1, (char *)"i",
(char *)"iio",
(int (*)(CSOUND *, void *))IAMPMIDID::init_,
(int (*)(CSOUND *, void *))0,
(int (*)(CSOUND *, void *))0);
status |= csound->AppendOpcode(csound, (char *)"ampmidid", 0xffff, 0, 0, 0, 0,
0, 0, 0);
status = csound->AppendOpcode(
csound, (char *)"ampmidicurve.k", sizeof(AMPMIDICURVE), 0, 3, (char *)"k",
(char *)"kkk",
(int (*)(CSOUND *, void *))AMPMIDICURVE::init_,
(int (*)(CSOUND *, void *))AMPMIDICURVE::kontrol_,
(int (*)(CSOUND *, void *))0);
status |= csound->AppendOpcode(
csound, (char *)"ampmidicurve.i", sizeof(AMPMIDICURVE), 0, 1, (char *)"i",
(char *)"iii",
(int (*)(CSOUND *, void *))AMPMIDICURVE::init_,
(int (*)(CSOUND *, void *))0,
(int (*)(CSOUND *, void *))0);
status |= csound->AppendOpcode(csound, (char *)"ampmidicurve", 0xffff, 0, 0, 0, 0,
0, 0, 0);
return status;
}
#ifndef INIT_STATIC_MODULES
PUBLIC int csoundModuleCreate(CSOUND *csound) {
IGN(csound);
return 0;
}
PUBLIC int csoundModuleInit(CSOUND *csound) {
return csoundModuleInit_ampmidid(csound);
}
PUBLIC int csoundModuleDestroy(CSOUND *csound) {
IGN(csound);
return 0;
}
#endif
}
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