ref: c3197de0732d863167944ca00c82f3e7165c8409
dir: /LEAF/Src/leaf-filters.c/
/*==============================================================================
leaf-filter.c
Created: 20 Jan 2017 12:01:10pm
Author: Michael R Mulshine
==============================================================================*/
#if _WIN32 || _WIN64
#include "..\Inc\leaf-filters.h"
#include "..\Inc\leaf-tables.h"
#include "..\leaf.h"
#else
#include "../Inc/leaf-filters.h"
#include "../Inc/leaf-tables.h"
#include "../leaf.h"
#include "tim.h"
#endif
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ OnePole Filter ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ //
void tAllpass_init(tAllpass* const ft, float initDelay, uint32_t maxDelay)
{
_tAllpass* f = *ft = (_tAllpass*) leaf_alloc(sizeof(_tAllpass));
f->gain = 0.7f;
f->lastOut = 0.0f;
tLinearDelay_init(&f->delay, initDelay, maxDelay);
}
void tAllpass_free(tAllpass* const ft)
{
_tAllpass* f = *ft;
tLinearDelay_free(&f->delay);
leaf_free(f);
}
void tAllpass_initToPool (tAllpass* const ft, float initDelay, uint32_t maxDelay, tMempool* const mp)
{
_tMempool* m = *mp;
_tAllpass* f = *ft = (_tAllpass*) mpool_alloc(sizeof(_tAllpass), m);
f->gain = 0.7f;
f->lastOut = 0.0f;
tLinearDelay_initToPool(&f->delay, initDelay, maxDelay, mp);
}
void tAllpass_freeFromPool (tAllpass* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tAllpass* f = *ft;
tLinearDelay_freeFromPool(&f->delay, mp);
mpool_free(f, m);
}
void tAllpass_setDelay(tAllpass* const ft, float delay)
{
_tAllpass* f = *ft;
tLinearDelay_setDelay(&f->delay, delay);
}
void tAllpass_setGain(tAllpass* const ft, float gain)
{
_tAllpass* f = *ft;
f->gain = gain;
}
float tAllpass_tick(tAllpass* const ft, float input)
{
_tAllpass* f = *ft;
float s1 = (-f->gain) * f->lastOut + input;
float s2 = tLinearDelay_tick(&f->delay, s1) + (f->gain) * input;
f->lastOut = s2;
return f->lastOut;
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ OnePole Filter ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ //
void tOnePole_init(tOnePole* const ft, float freq)
{
_tOnePole* f = *ft = (_tOnePole*) leaf_alloc(sizeof(_tOnePole));
f->gain = 1.0f;
f->a0 = 1.0;
tOnePole_setFreq(ft, freq);
f->lastIn = 0.0f;
f->lastOut = 0.0f;
}
void tOnePole_free(tOnePole* const ft)
{
_tOnePole* f = *ft;
leaf_free(f);
}
void tOnePole_initToPool (tOnePole* const ft, float freq, tMempool* const mp)
{
_tMempool* m = *mp;
_tOnePole* f = *ft = (_tOnePole*) mpool_alloc(sizeof(_tOnePole), m);
f->gain = 1.0f;
f->a0 = 1.0;
tOnePole_setFreq(ft, freq);
f->lastIn = 0.0f;
f->lastOut = 0.0f;
}
void tOnePole_freeFromPool (tOnePole* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tOnePole* f = *ft;
mpool_free(f, m);
}
void tOnePole_setB0(tOnePole* const ft, float b0)
{
_tOnePole* f = *ft;
f->b0 = b0;
}
void tOnePole_setA1(tOnePole* const ft, float a1)
{
_tOnePole* f = *ft;
if (a1 >= 1.0f) a1 = 0.999999f;
f->a1 = a1;
}
void tOnePole_setPole(tOnePole* const ft, float thePole)
{
_tOnePole* f = *ft;
if (thePole >= 1.0f) thePole = 0.999999f;
// Normalize coefficients for peak unity gain.
if (thePole > 0.0f) f->b0 = (1.0f - thePole);
else f->b0 = (1.0f + thePole);
f->a1 = -thePole;
}
void tOnePole_setFreq (tOnePole* const ft, float freq)
{
_tOnePole* f = *ft;
f->b0 = freq * leaf.twoPiTimesInvSampleRate;
f->b0 = LEAF_clip(0.0f, f->b0, 1.0f);
f->a1 = 1.0f - f->b0;
}
void tOnePole_setCoefficients(tOnePole* const ft, float b0, float a1)
{
_tOnePole* f = *ft;
if (a1 >= 1.0f) a1 = 0.999999f;
f->b0 = b0;
f->a1 = a1;
}
void tOnePole_setGain(tOnePole* const ft, float gain)
{
_tOnePole* f = *ft;
f->gain = gain;
}
float tOnePole_tick(tOnePole* const ft, float input)
{
_tOnePole* f = *ft;
float in = input * f->gain;
float out = (f->b0 * in) + (f->a1 * f->lastOut);
f->lastIn = in;
f->lastOut = out;
return out;
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ TwoPole Filter ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ //
void tTwoPole_init(tTwoPole* const ft)
{
_tTwoPole* f = *ft = (_tTwoPole*) leaf_alloc(sizeof(_tTwoPole));
f->gain = 1.0f;
f->a0 = 1.0;
f->b0 = 1.0;
f->lastOut[0] = 0.0f;
f->lastOut[1] = 0.0f;
}
void tTwoPole_free(tTwoPole* const ft)
{
_tTwoPole* f = *ft;
leaf_free(f);
}
void tTwoPole_initToPool (tTwoPole* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tTwoPole* f = *ft = (_tTwoPole*) mpool_alloc(sizeof(_tTwoPole), m);
f->gain = 1.0f;
f->a0 = 1.0;
f->b0 = 1.0;
f->lastOut[0] = 0.0f;
f->lastOut[1] = 0.0f;
}
void tTwoPole_freeFromPool (tTwoPole* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tTwoPole* f = *ft;
mpool_free(f, m);
}
float tTwoPole_tick(tTwoPole* const ft, float input)
{
_tTwoPole* f = *ft;
float in = input * f->gain;
float out = (f->b0 * in) - (f->a1 * f->lastOut[0]) - (f->a2 * f->lastOut[1]);
f->lastOut[1] = f->lastOut[0];
f->lastOut[0] = out;
return out;
}
void tTwoPole_setB0(tTwoPole* const ft, float b0)
{
_tTwoPole* f = *ft;
f->b0 = b0;
}
void tTwoPole_setA1(tTwoPole* const ft, float a1)
{
_tTwoPole* f = *ft;
f->a1 = a1;
}
void tTwoPole_setA2(tTwoPole* const ft, float a2)
{
_tTwoPole* f = *ft;
f->a2 = a2;
}
void tTwoPole_setResonance(tTwoPole* const ft, float frequency, float radius, oBool normalize)
{
_tTwoPole* f = *ft;
if (frequency < 0.0f) frequency = 0.0f;
if (frequency > (leaf.sampleRate * 0.49f)) frequency = leaf.sampleRate * 0.49f;
if (radius < 0.0f) radius = 0.0f;
if (radius >= 1.0f) radius = 0.999999f;
f->radius = radius;
f->frequency = frequency;
f->normalize = normalize;
f->a2 = radius * radius;
f->a1 = -2.0f * radius * cosf(frequency * leaf.twoPiTimesInvSampleRate);
if ( normalize )
{
// Normalize the filter gain ... not terribly efficient.
float real = 1 - radius + (f->a2 - radius) * cosf(2 * frequency * leaf.twoPiTimesInvSampleRate);
float imag = (f->a2 - radius) * sinf(2 * frequency * leaf.twoPiTimesInvSampleRate);
f->b0 = sqrtf( powf(real, 2) + powf(imag, 2) );
}
}
void tTwoPole_setCoefficients(tTwoPole* const ft, float b0, float a1, float a2)
{
_tTwoPole* f = *ft;
f->b0 = b0;
f->a1 = a1;
f->a2 = a2;
}
void tTwoPole_setGain(tTwoPole* const ft, float gain)
{
_tTwoPole* f = *ft;
f->gain = gain;
}
void tTwoPoleSampleRateChanged (tTwoPole* const ft)
{
_tTwoPole* f = *ft;
f->a2 = f->radius * f->radius;
f->a1 = -2.0f * f->radius * cosf(f->frequency * leaf.twoPiTimesInvSampleRate);
if ( f->normalize )
{
// Normalize the filter gain ... not terribly efficient.
float real = 1 - f->radius + (f->a2 - f->radius) * cosf(2 * f->frequency * leaf.twoPiTimesInvSampleRate);
float imag = (f->a2 - f->radius) * sinf(2 * f->frequency * leaf.twoPiTimesInvSampleRate);
f->b0 = sqrtf( powf(real, 2) + powf(imag, 2) );
}
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ OneZero Filter ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ //
void tOneZero_init(tOneZero* const ft, float theZero)
{
_tOneZero* f = *ft = (_tOneZero*) leaf_alloc(sizeof(_tOneZero));
f->gain = 1.0f;
f->lastIn = 0.0f;
f->lastOut = 0.0f;
tOneZero_setZero(ft, theZero);
}
void tOneZero_free(tOneZero* const ft)
{
_tOneZero* f = *ft;
leaf_free(f);
}
void tOneZero_initToPool (tOneZero* const ft, float theZero, tMempool* const mp)
{
_tMempool* m = *mp;
_tOneZero* f = *ft = (_tOneZero*) mpool_alloc(sizeof(_tOneZero), m);
f->gain = 1.0f;
f->lastIn = 0.0f;
f->lastOut = 0.0f;
tOneZero_setZero(ft, theZero);
}
void tOneZero_freeFromPool (tOneZero* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tOneZero* f = *ft;
mpool_free(f, m);
}
float tOneZero_tick(tOneZero* const ft, float input)
{
_tOneZero* f = *ft;
float in = input * f->gain;
float out = f->b1 * f->lastIn + f->b0 * in;
f->lastIn = in;
return out;
}
void tOneZero_setZero(tOneZero* const ft, float theZero)
{
_tOneZero* f = *ft;
if (theZero > 0.0f) f->b0 = 1.0f / (1.0f + theZero);
else f->b0 = 1.0f / (1.0f - theZero);
f->b1 = -theZero * f->b0;
}
void tOneZero_setB0(tOneZero* const ft, float b0)
{
_tOneZero* f = *ft;
f->b0 = b0;
}
void tOneZero_setB1(tOneZero* const ft, float b1)
{
_tOneZero* f = *ft;
f->b1 = b1;
}
void tOneZero_setCoefficients(tOneZero* const ft, float b0, float b1)
{
_tOneZero* f = *ft;
f->b0 = b0;
f->b1 = b1;
}
void tOneZero_setGain(tOneZero *ft, float gain)
{
_tOneZero* f = *ft;
f->gain = gain;
}
float tOneZero_getPhaseDelay(tOneZero* const ft, float frequency )
{
_tOneZero* f = *ft;
if ( frequency <= 0.0f) frequency = 0.05f;
f->frequency = frequency;
float omegaT = 2 * PI * frequency * leaf.invSampleRate;
float real = 0.0, imag = 0.0;
real += f->b0;
real += f->b1 * cosf(omegaT);
imag -= f->b1 * sinf(omegaT);
real *= f->gain;
imag *= f->gain;
float phase = atan2f( imag, real );
real = 0.0; imag = 0.0;
phase -= atan2f( imag, real );
phase = fmodf( -phase, 2 * PI );
return phase / omegaT;
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ TwoZero Filter ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ //
void tTwoZero_init(tTwoZero* const ft)
{
_tTwoZero* f = *ft = (_tTwoZero*) leaf_alloc(sizeof(_tTwoZero));
f->gain = 1.0f;
f->lastIn[0] = 0.0f;
f->lastIn[1] = 0.0f;
}
void tTwoZero_free(tTwoZero* const ft)
{
_tTwoZero* f = *ft;
leaf_free(f);
}
void tTwoZero_initToPool (tTwoZero* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tTwoZero* f = *ft = (_tTwoZero*) mpool_alloc(sizeof(_tTwoZero), m);
f->gain = 1.0f;
f->lastIn[0] = 0.0f;
f->lastIn[1] = 0.0f;
}
void tTwoZero_freeFromPool (tTwoZero* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tTwoZero* f = *ft;
mpool_free(f, m);
}
float tTwoZero_tick(tTwoZero* const ft, float input)
{
_tTwoZero* f = *ft;
float in = input * f->gain;
float out = f->b2 * f->lastIn[1] + f->b1 * f->lastIn[0] + f->b0 * in;
f->lastIn[1] = f->lastIn[0];
f->lastIn[0] = in;
return out;
}
void tTwoZero_setNotch(tTwoZero* const ft, float freq, float radius)
{
_tTwoZero* f = *ft;
// Should also deal with frequency being > half sample rate / nyquist. See STK
if (freq < 0.0f) freq = 0.0f;
if (radius < 0.0f) radius = 0.0f;
f->frequency = freq;
f->radius = radius;
f->b2 = radius * radius;
f->b1 = -2.0f * radius * cosf(freq * leaf.twoPiTimesInvSampleRate); // OPTIMIZE with LOOKUP or APPROXIMATION
// Normalize the filter gain. From STK.
if ( f->b1 > 0.0f ) // Maximum at z = 0.
f->b0 = 1.0f / ( 1.0f + f->b1 + f->b2 );
else // Maximum at z = -1.
f->b0 = 1.0f / ( 1.0f - f->b1 + f->b2 );
f->b1 *= f->b0;
f->b2 *= f->b0;
}
void tTwoZero_setB0(tTwoZero* const ft, float b0)
{
_tTwoZero* f = *ft;
f->b0 = b0;
}
void tTwoZero_setB1(tTwoZero* const ft, float b1)
{
_tTwoZero* f = *ft;
f->b1 = b1;
}
void tTwoZero_setCoefficients(tTwoZero* const ft, float b0, float b1, float b2)
{
_tTwoZero* f = *ft;
f->b0 = b0;
f->b1 = b1;
f->b2 = b2;
}
void tTwoZero_setGain(tTwoZero* const ft, float gain)
{
_tTwoZero* f = *ft;
f->gain = gain;
}
void tTwoZeroSampleRateChanged(tTwoZero* const ft)
{
_tTwoZero* f = *ft;
tTwoZero_setNotch(ft, f->frequency, f->radius);
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ PoleZero Filter ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ //
void tPoleZero_init(tPoleZero* const pzf)
{
_tPoleZero* f = *pzf = (_tPoleZero*) leaf_alloc(sizeof(_tPoleZero));
f->gain = 1.0f;
f->b0 = 1.0;
f->a0 = 1.0;
f->lastIn = 0.0f;
f->lastOut = 0.0f;
}
void tPoleZero_free(tPoleZero* const pzf)
{
_tPoleZero* f = *pzf;
leaf_free(f);
}
void tPoleZero_initToPool (tPoleZero* const pzf, tMempool* const mp)
{
_tMempool* m = *mp;
_tPoleZero* f = *pzf = (_tPoleZero*) mpool_alloc(sizeof(_tPoleZero), m);
f->gain = 1.0f;
f->b0 = 1.0;
f->a0 = 1.0;
f->lastIn = 0.0f;
f->lastOut = 0.0f;
}
void tPoleZero_freeFromPool (tPoleZero* const pzf, tMempool* const mp)
{
_tMempool* m = *mp;
_tPoleZero* f = *pzf;
mpool_free(f, m);
}
void tPoleZero_setB0(tPoleZero* const pzf, float b0)
{
_tPoleZero* f = *pzf;
f->b0 = b0;
}
void tPoleZero_setB1(tPoleZero* const pzf, float b1)
{
_tPoleZero* f = *pzf;
f->b1 = b1;
}
void tPoleZero_setA1(tPoleZero* const pzf, float a1)
{
_tPoleZero* f = *pzf;
if (a1 >= 1.0f) // a1 should be less than 1.0
{
a1 = 0.999999f;
}
f->a1 = a1;
}
void tPoleZero_setCoefficients(tPoleZero* const pzf, float b0, float b1, float a1)
{
_tPoleZero* f = *pzf;
if (a1 >= 1.0f) // a1 should be less than 1.0
{
a1 = 0.999999f;
}
f->b0 = b0;
f->b1 = b1;
f->a1 = a1;
}
void tPoleZero_setAllpass(tPoleZero* const pzf, float coeff)
{
_tPoleZero* f = *pzf;
if (coeff >= 1.0f) // allpass coefficient >= 1.0 makes filter unstable
{
coeff = 0.999999f;
}
f->b0 = coeff;
f->b1 = 1.0f;
f->a0 = 1.0f;
f->a1 = coeff;
}
void tPoleZero_setBlockZero(tPoleZero* const pzf, float thePole)
{
_tPoleZero* f = *pzf;
if (thePole >= 1.0f) // allpass coefficient >= 1.0 makes filter unstable
{
thePole = 0.999999f;
}
f->b0 = 1.0f;
f->b1 = -1.0f;
f->a0 = 1.0f;
f->a1 = -thePole;
}
void tPoleZero_setGain(tPoleZero* const pzf, float gain)
{
_tPoleZero* f = *pzf;
f->gain = gain;
}
float tPoleZero_tick(tPoleZero* const pzf, float input)
{
_tPoleZero* f = *pzf;
float in = input * f->gain;
float out = (f->b0 * in) + (f->b1 * f->lastIn) - (f->a1 * f->lastOut);
f->lastIn = in;
f->lastOut = out;
return out;
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ BiQuad Filter ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ //
void tBiQuad_init(tBiQuad* const ft)
{
_tBiQuad* f = *ft = (_tBiQuad*) leaf_alloc(sizeof(_tBiQuad));
f->gain = 1.0f;
f->b0 = 0.0f;
f->a0 = 0.0f;
f->lastIn[0] = 0.0f;
f->lastIn[1] = 0.0f;
f->lastOut[0] = 0.0f;
f->lastOut[1] = 0.0f;
}
void tBiQuad_free(tBiQuad* const ft)
{
_tBiQuad* f = *ft;
leaf_free(f);
}
void tBiQuad_initToPool (tBiQuad* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tBiQuad* f = *ft = (_tBiQuad*) mpool_alloc(sizeof(_tBiQuad), m);
f->gain = 1.0f;
f->b0 = 0.0f;
f->a0 = 0.0f;
f->lastIn[0] = 0.0f;
f->lastIn[1] = 0.0f;
f->lastOut[0] = 0.0f;
f->lastOut[1] = 0.0f;
}
void tBiQuad_freeFromPool (tBiQuad* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tBiQuad* f = *ft;
mpool_free(f, m);
}
float tBiQuad_tick(tBiQuad* const ft, float input)
{
_tBiQuad* f = *ft;
float in = input * f->gain;
float out = f->b0 * in + f->b1 * f->lastIn[0] + f->b2 * f->lastIn[1];
out -= f->a2 * f->lastOut[1] + f->a1 * f->lastOut[0];
f->lastIn[1] = f->lastIn[0];
f->lastIn[0] = in;
f->lastOut[1] = f->lastOut[0];
f->lastOut[0] = out;
return out;
}
void tBiQuad_setResonance(tBiQuad* const ft, float freq, float radius, oBool normalize)
{
_tBiQuad* f = *ft;
if (freq < 0.0f) freq = 0.0f;
if (freq > (leaf.sampleRate * 0.49f)) freq = leaf.sampleRate * 0.49f;
if (radius < 0.0f) radius = 0.0f;
if (radius >= 1.0f) radius = 1.0f;
f->frequency = freq;
f->radius = radius;
f->normalize = normalize;
f->a2 = radius * radius;
f->a1 = -2.0f * radius * cosf(freq * leaf.twoPiTimesInvSampleRate);
if (normalize)
{
f->b0 = 0.5f - 0.5f * f->a2;
f->b1 = 0.0f;
f->b2 = -f->b0;
}
}
void tBiQuad_setNotch(tBiQuad* const ft, float freq, float radius)
{
_tBiQuad* f = *ft;
if (freq < 0.0f) freq = 0.0f;
if (freq > (leaf.sampleRate * 0.49f)) freq = leaf.sampleRate * 0.49f;
if (radius < 0.0f) radius = 0.0f;
f->b2 = radius * radius;
f->b1 = -2.0f * radius * cosf(freq * leaf.twoPiTimesInvSampleRate); // OPTIMIZE with LOOKUP or APPROXIMATION
// Does not attempt to normalize filter gain.
}
void tBiQuad_setEqualGainZeros(tBiQuad* const ft)
{
_tBiQuad* f = *ft;
f->b0 = 1.0f;
f->b1 = 0.0f;
f->b2 = -1.0f;
}
void tBiQuad_setB0(tBiQuad* const ft, float b0)
{
_tBiQuad* f = *ft;
f->b0 = b0;
}
void tBiQuad_setB1(tBiQuad* const ft, float b1)
{
_tBiQuad* f = *ft;
f->b1 = b1;
}
void tBiQuad_setB2(tBiQuad* const ft, float b2)
{
_tBiQuad* f = *ft;
f->b2 = b2;
}
void tBiQuad_setA1(tBiQuad* const ft, float a1)
{
_tBiQuad* f = *ft;
f->a1 = a1;
}
void tBiQuad_setA2(tBiQuad* const ft, float a2)
{
_tBiQuad* f = *ft;
f->a2 = a2;
}
void tBiQuad_setCoefficients(tBiQuad* const ft, float b0, float b1, float b2, float a1, float a2)
{
_tBiQuad* f = *ft;
f->b0 = b0;
f->b1 = b1;
f->b2 = b2;
f->a1 = a1;
f->a2 = a2;
}
void tBiQuad_setGain(tBiQuad* const ft, float gain)
{
_tBiQuad* f = *ft;
f->gain = gain;
}
void tBiQuadSampleRateChanged(tBiQuad* const ft)
{
_tBiQuad* f = *ft;
f->a2 = f->radius * f->radius;
f->a1 = -2.0f * f->radius * cosf(f->frequency * leaf.twoPiTimesInvSampleRate);
if (f->normalize)
{
f->b0 = 0.5f - 0.5f * f->a2;
f->b1 = 0.0f;
f->b2 = -f->b0;
}
}
// Less efficient, more accurate version of SVF, in which cutoff frequency is taken as floating point Hz value and tanf
// is calculated when frequency changes.
void tSVF_init(tSVF* const svff, SVFType type, float freq, float Q)
{
_tSVF* svf = *svff = (_tSVF*) leaf_alloc(sizeof(_tSVF));
svf->type = type;
svf->ic1eq = 0;
svf->ic2eq = 0;
svf->g = tanf(PI * freq * leaf.invSampleRate);
svf->k = 1.0f/Q;
svf->a1 = 1.0f/(1.0f + svf->g * (svf->g + svf->k));
svf->a2 = svf->g*svf->a1;
svf->a3 = svf->g*svf->a2;
if (type == SVFTypeLowpass)
{
svf->cH = 0.0f;
svf->cB = 0.0f;
svf->kAmount = 0.0f;
svf->cL = 1.0f;
}
else if (type == SVFTypeBandpass)
{
svf->cH = 0.0f;
svf->cB = 1.0f;
svf->kAmount = 0.0f;
svf->cL = 0.0f;
}
else if (type == SVFTypeHighpass)
{
svf->cH = 1.0f;
svf->cB = svf->k * -1.0f;
svf->kAmount = 1.0f;
svf->cL = -1.0f;
}
else if (type == SVFTypeNotch)
{
svf->cH = 1.0f;
svf->cB = svf->k * -1.0f;
svf->kAmount = 1.0f;
svf->cL = 0.0f;
}
else if (type == SVFTypePeak)
{
svf->cH = 1.0f;
svf->cB = svf->k * -1.0f;
svf->kAmount = 1.0f;
svf->cL = -2.0f;
}
// or maybe this?
/*
* hp=1 bp=A/Q (where A is 10^(G/40) and G is gain in decibels) and lp = 1
*/
}
void tSVF_free(tSVF* const svff)
{
_tSVF* svf = *svff;
leaf_free(svf);
}
void tSVF_initToPool (tSVF* const svff, SVFType type, float freq, float Q, tMempool* const mp)
{
_tMempool* m = *mp;
_tSVF* svf = *svff = (_tSVF*) mpool_alloc(sizeof(_tSVF), m);
svf->type = type;
svf->ic1eq = 0;
svf->ic2eq = 0;
svf->g = tanf(PI * freq * leaf.invSampleRate);
svf->k = 1.0f/Q;
svf->a1 = 1.0f/(1.0f + svf->g * (svf->g + svf->k));
svf->a2 = svf->g*svf->a1;
svf->a3 = svf->g*svf->a2;
svf->cH = 0.0f;
svf->cB = 0.0f;
svf->cL = 1.0f;
}
void tSVF_freeFromPool (tSVF* const svff, tMempool* const mp)
{
_tMempool* m = *mp;
_tSVF* svf = *svff;
mpool_free(svf, m);
}
float tSVF_tick(tSVF* const svff, float v0)
{
_tSVF* svf = *svff;
float v1,v2,v3;
v3 = v0 - svf->ic2eq;
v1 = (svf->a1 * svf->ic1eq) + (svf->a2 * v3);
v2 = svf->ic2eq + (svf->a2 * svf->ic1eq) + (svf->a3 * v3);
svf->ic1eq = (2.0f * v1) - svf->ic1eq;
svf->ic2eq = (2.0f * v2) - svf->ic2eq;
return (v0 * svf->cH) + (svf->kAmount * svf->k * v1 * svf->cB) + (v2 * svf->cL);
}
void tSVF_setFreq(tSVF* const svff, float freq)
{
_tSVF* svf = *svff;
svf->g = tanf(PI * freq * leaf.invSampleRate);
svf->a1 = 1.0f/(1.0f + svf->g * (svf->g + svf->k));
svf->a2 = svf->g * svf->a1;
svf->a3 = svf->g * svf->a2;
}
void tSVF_setQ(tSVF* const svff, float Q)
{
_tSVF* svf = *svff;
svf->k = 1.0f/Q;
svf->a1 = 1.0f/(1.0f + svf->g * (svf->g + svf->k));
svf->a2 = svf->g * svf->a1;
svf->a3 = svf->g * svf->a2;
}
void tSVF_setFreqAndQ(tSVF* const svff, float freq, float Q)
{
_tSVF* svf = *svff;
svf->k = 1.0f/Q;
svf->g = tanf(PI * freq * leaf.invSampleRate);
svf->a1 = 1.0f/(1.0f + svf->g * (svf->g + svf->k));
svf->a2 = svf->g * svf->a1;
svf->a3 = svf->g * svf->a2;
}
// Efficient version of tSVF where frequency is set based on 12-bit integer input for lookup in tanh wavetable.
void tEfficientSVF_init(tEfficientSVF* const svff, SVFType type, uint16_t input, float Q)
{
_tEfficientSVF* svf = *svff = (_tEfficientSVF*) leaf_alloc(sizeof(_tEfficientSVF));
svf->type = type;
svf->ic1eq = 0;
svf->ic2eq = 0;
svf->g = __leaf_table_filtertan[input];
svf->k = 1.0f/Q;
svf->a1 = 1.0f/(1.0f+svf->g*(svf->g+svf->k));
svf->a2 = svf->g*svf->a1;
svf->a3 = svf->g*svf->a2;
}
void tEfficientSVF_free(tEfficientSVF* const svff)
{
_tEfficientSVF* svf = *svff;
leaf_free(svf);
}
void tEfficientSVF_initToPool (tEfficientSVF* const svff, SVFType type, uint16_t input, float Q, tMempool* const mp)
{
_tMempool* m = *mp;
_tEfficientSVF* svf = *svff = (_tEfficientSVF*) mpool_alloc(sizeof(_tEfficientSVF), m);
svf->type = type;
svf->ic1eq = 0;
svf->ic2eq = 0;
svf->g = __leaf_table_filtertan[input];
svf->k = 1.0f/Q;
svf->a1 = 1.0f/(1.0f+svf->g*(svf->g+svf->k));
svf->a2 = svf->g*svf->a1;
svf->a3 = svf->g*svf->a2;
}
void tEfficientSVF_freeFromPool (tEfficientSVF* const svff, tMempool* const mp)
{
_tMempool* m = *mp;
_tEfficientSVF* svf = *svff;
mpool_free(svf, m);
}
float tEfficientSVF_tick(tEfficientSVF* const svff, float v0)
{
_tEfficientSVF* svf = *svff;
float v1,v2,v3;
v3 = v0 - svf->ic2eq;
v1 = (svf->a1 * svf->ic1eq) + (svf->a2 * v3);
v2 = svf->ic2eq + (svf->a2 * svf->ic1eq) + (svf->a3 * v3);
svf->ic1eq = (2.0f * v1) - svf->ic1eq;
svf->ic2eq = (2.0f * v2) - svf->ic2eq;
if (svf->type == SVFTypeLowpass) return v2;
else if (svf->type == SVFTypeBandpass) return v1;
else if (svf->type == SVFTypeHighpass) return v0 - (svf->k * v1) - v2;
else if (svf->type == SVFTypeNotch) return v0 - (svf->k * v1);
else if (svf->type == SVFTypePeak) return v0 - (svf->k * v1) - (2.0f * v2);
else return 0.0f;
}
void tEfficientSVF_setFreq(tEfficientSVF* const svff, uint16_t input)
{
_tEfficientSVF* svf = *svff;
svf->g = __leaf_table_filtertan[input];
svf->a1 = 1.0f/(1.0f + svf->g * (svf->g + svf->k));
svf->a2 = svf->g * svf->a1;
svf->a3 = svf->g * svf->a2;
}
void tEfficientSVF_setQ(tEfficientSVF* const svff, float Q)
{
_tEfficientSVF* svf = *svff;
svf->k = 1.0f/Q;
svf->a1 = 1.0f/(1.0f + svf->g * (svf->g + svf->k));
svf->a2 = svf->g * svf->a1;
svf->a3 = svf->g * svf->a2;
}
/* Highpass */
void tHighpass_init(tHighpass* const ft, float freq)
{
_tHighpass* f = *ft = (_tHighpass*) leaf_alloc(sizeof(_tHighpass));
f->R = (1.0f - (freq * leaf.twoPiTimesInvSampleRate));
f->ys = 0.0f;
f->xs = 0.0f;
f->frequency = freq;
}
void tHighpass_free(tHighpass* const ft)
{
_tHighpass* f = *ft;
leaf_free(f);
}
void tHighpass_initToPool (tHighpass* const ft, float freq, tMempool* const mp)
{
_tMempool* m = *mp;
_tHighpass* f = *ft = (_tHighpass*) mpool_calloc(sizeof(_tHighpass), m);
f->R = (1.0f - (freq * leaf.twoPiTimesInvSampleRate));
f->ys = 0.0f;
f->xs = 0.0f;
f->frequency = freq;
}
void tHighpass_freeFromPool (tHighpass* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tHighpass* f = *ft;
mpool_free(f, m);
}
void tHighpass_setFreq(tHighpass* const ft, float freq)
{
_tHighpass* f = *ft;
f->frequency = freq;
f->R = (1.0f - (freq * leaf.twoPiTimesInvSampleRate));
}
float tHighpass_getFreq(tHighpass* const ft)
{
_tHighpass* f = *ft;
return f->frequency;
}
// From JOS DC Blocker
float tHighpass_tick(tHighpass* const ft, float x)
{
_tHighpass* f = *ft;
f->ys = x - f->xs + f->R * f->ys;
f->xs = x;
return f->ys;
}
void tHighpassSampleRateChanged(tHighpass* const ft)
{
_tHighpass* f = *ft;
f->R = (1.0f-((f->frequency * 2.0f * 3.14f) * leaf.invSampleRate));
}
void tButterworth_init(tButterworth* const ft, int N, float f1, float f2)
{
_tButterworth* f = *ft = (_tButterworth*) leaf_alloc(sizeof(_tButterworth));
f->f1 = f1;
f->f2 = f2;
f->gain = 1.0f;
f->N = N;
if (f->N > NUM_SVF_BW) f->N = NUM_SVF_BW;
for(int i = 0; i < N/2; ++i)
{
tSVF_init(&f->low[i], SVFTypeHighpass, f1, 0.5f/cosf((1.0f+2.0f*i)*PI/(2*N)));
tSVF_init(&f->high[i], SVFTypeLowpass, f2, 0.5f/cosf((1.0f+2.0f*i)*PI/(2*N)));
}
}
void tButterworth_free(tButterworth* const ft)
{
_tButterworth* f = *ft;
for(int i = 0; i < f->N/2; ++i)
{
tSVF_free(&f->low[i]);
tSVF_free(&f->high[i]);
}
leaf_free(f);
}
void tButterworth_initToPool (tButterworth* const ft, int N, float f1, float f2, tMempool* const mp)
{
_tMempool* m = *mp;
_tButterworth* f = *ft = (_tButterworth*) mpool_alloc(sizeof(_tButterworth), m);
f->f1 = f1;
f->f2 = f2;
f->gain = 1.0f;
f->N = N;
if (f->N > NUM_SVF_BW) f->N = NUM_SVF_BW;
for(int i = 0; i < N/2; ++i)
{
tSVF_initToPool(&f->low[i], SVFTypeHighpass, f1, 0.5f/cosf((1.0f+2.0f*i)*PI/(2*N)), mp);
tSVF_initToPool(&f->high[i], SVFTypeLowpass, f2, 0.5f/cosf((1.0f+2.0f*i)*PI/(2*N)), mp);
}
}
void tButterworth_freeFromPool (tButterworth* const ft, tMempool* const mp)
{
_tMempool* m = *mp;
_tButterworth* f = *ft;
for(int i = 0; i < f->N/2; ++i)
{
tSVF_freeFromPool(&f->low[i], mp);
tSVF_freeFromPool(&f->high[i], mp);
}
mpool_free(f, m);
}
float tButterworth_tick(tButterworth* const ft, float samp)
{
_tButterworth* f = *ft;
for(int i = 0; i < ((f->N)/2); ++i)
{
samp = tSVF_tick(&f->low[i],samp);
samp = tSVF_tick(&f->high[i],samp);
}
return samp;
}
void tButterworth_setF1(tButterworth* const ft, float f1)
{
_tButterworth* f = *ft;
f->f1 = f1;
for(int i = 0; i < ((f->N)/2); ++i) tSVF_setFreq(&f->low[i], f1);
}
void tButterworth_setF2(tButterworth* const ft, float f2)
{
_tButterworth* f = *ft;
f->f2 = f2;
for(int i = 0; i < ((f->N)/2); ++i) tSVF_setFreq(&f->high[i], f2);
}
void tButterworth_setFreqs(tButterworth* const ft, float f1, float f2)
{
_tButterworth* f = *ft;
f->f1 = f1;
f->f2 = f2;
for(int i = 0; i < ((f->N)/2); ++i)
{
tSVF_setFreq(&f->low[i], f1);
tSVF_setFreq(&f->high[i], f2);
}
}
void tFIR_init(tFIR* const firf, float* coeffs, int numTaps)
{
_tFIR* fir = *firf = (_tFIR*) leaf_alloc(sizeof(_tFIR));
fir->numTaps = numTaps;
fir->coeff = coeffs;
fir->past = (float*)leaf_alloc(sizeof(float) * fir->numTaps);
for (int i = 0; i < fir->numTaps; ++i) fir->past[i] = 0.0f;
}
void tFIR_free(tFIR* const firf)
{
_tFIR* fir = *firf;
leaf_free(fir->past);
leaf_free(fir);
}
void tFIR_initToPool (tFIR* const firf, float* coeffs, int numTaps, tMempool* const mp)
{
_tMempool* m = *mp;
_tFIR* fir = *firf = (_tFIR*) mpool_alloc(sizeof(_tFIR), m);
fir->numTaps = numTaps;
fir->coeff = coeffs;
fir->past = (float*) mpool_alloc(sizeof(float) * fir->numTaps, m);
for (int i = 0; i < fir->numTaps; ++i) fir->past[i] = 0.0f;
}
void tFIR_freeFromPool (tFIR* const firf, tMempool* const mp)
{
_tMempool* m = *mp;
_tFIR* fir = *firf;
mpool_free(fir->past, m);
mpool_free(fir, m);
}
float tFIR_tick(tFIR* const firf, float input)
{
_tFIR* fir = *firf;
fir->past[0] = input;
float y = 0.0f;
for (int i = 0; i < fir->numTaps; ++i) y += fir->past[i]*fir->coeff[i];
for (int i = fir->numTaps-1; i > 0; --i) fir->past[i] = fir->past[i-1];
return y;
}
//---------------------------------------------
////
/// Median filter implemented based on James McCartney's median filter in Supercollider,
/// translated from a Gen~ port of the Supercollider code that I believe was made by Rodrigo Costanzo and which I got from PA Tremblay - JS
void tMedianFilter_init (tMedianFilter* const f, int size)
{
tMedianFilter_initToPool(f, size, &leaf.mempool);
}
void tMedianFilter_free (tMedianFilter* const f)
{
tMedianFilter_freeFromPool(f, &leaf.mempool);
}
void tMedianFilter_initToPool (tMedianFilter* const mf, int size, tMempool* const mp)
{
_tMempool* m = *mp;
_tMedianFilter* f = *mf = (_tMedianFilter*) mpool_alloc(sizeof(_tMedianFilter), m);
f->size = size;
f->middlePosition = size / 2;
f->last = size - 1;
f->pos = -1;
f->val = (float*) mpool_alloc(sizeof(float) * size, m);
f->age = (int*) mpool_alloc(sizeof(int) * size, m);
for (int i = 0; i < f->size; ++i)
{
f->val[i] = 0.0f;
f->age[i] = i;
}
}
void tMedianFilter_freeFromPool (tMedianFilter* const mf, tMempool* const mp)
{
_tMempool* m = *mp;
_tMedianFilter* f = *mf;
mpool_free(f->val, m);
mpool_free(f->age, m);
mpool_free(f, m);
}
float tMedianFilter_tick (tMedianFilter* const mf, float input)
{
_tMedianFilter* f = *mf;
for(int i=0; i<f->size; i++) {
int thisAge = f->age[i];
if(thisAge == f->last) {
f->pos = i;
}
else {
thisAge++;
f->age[i] = thisAge;
}
}
while( f->pos!=0 ) {
float test = f->val[f->pos-1];
if(input < test) {
f->val[f->pos]=test;
f->age[f->pos]=f->age[f->pos-1];
f->pos -= 1;
} else {break;}
}
while(f->pos != f->last) {
float test = f->val[f->pos+1];
if( input > test) {
f->val[f->pos] = test;
f->age[f->pos] = f->age[f->pos+1];
f->pos += 1;
} else {break;}
}
f->val[f->pos] = input;
f->age[f->pos] = 0;
return f->val[f->middlePosition];
}
void tVZFilter_init (tVZFilter* const vf, VZFilterType type, float freq, float bandWidth)
{
tVZFilter_initToPool(vf, type, freq, bandWidth, &leaf.mempool);
}
void tVZFilter_free (tVZFilter* const vf)
{
tVZFilter_freeFromPool(vf, &leaf.mempool);
}
void tVZFilter_initToPool (tVZFilter* const vf, VZFilterType type, float freq, float bandWidth, tMempool* const mp)
{
_tMempool* m = *mp;
_tVZFilter* f = *vf = (_tVZFilter*) mpool_alloc(sizeof(_tVZFilter), m);
f->fc = freq;
f->type = type;
f->G = ONE_OVER_SQRT2;
f->B = bandWidth;
f->m = 0.0f;
f->s1 = 0.0f;
f->s2 = 0.0f;
f->sr = leaf.sampleRate;
f->inv_sr = leaf.invSampleRate;
tVZFilter_calcCoeffs(vf);
}
void tVZFilter_freeFromPool (tVZFilter* const vf, tMempool* const mp)
{
_tMempool* m = *mp;
_tVZFilter* f = *vf = (_tVZFilter*) mpool_alloc(sizeof(_tVZFilter), m);
mpool_free(f, m);
}
void tVZFilter_setSampleRate (tVZFilter* const vf, float sampleRate)
{
_tVZFilter* f = *vf;
f->sr = sampleRate;
f->inv_sr = 1.0f/sampleRate;
}
float tVZFilter_tick (tVZFilter* const vf, float in)
{
_tVZFilter* f = *vf;
float yL, yB, yH;
// compute highpass output via Eq. 5.1:
yH = (in - f->R2*f->s1 - f->g*f->s1 - f->s2) * f->h;
// compute bandpass output by applying 1st integrator to highpass output:
yB = tanhf(f->g*yH) + f->s1;
f->s1 = f->g*yH + yB; // state update in 1st integrator
// compute lowpass output by applying 2nd integrator to bandpass output:
yL = tanhf(f->g*yB) + f->s2;
f->s2 = f->g*yB + yL; // state update in 2nd integrator
//according to the Vadim paper, we could add saturation to this model by adding a tanh in the integration stage.
//
//seems like that might look like this:
// y = tanh(g*x) + s; // output computation
// s = g*x + y; // state update
//instead of this:
// y = g*x + s; // output computation
// s = g*x + y; // state update
return f->cL*yL + f->cB*yB + f->cH*yH;
}
void tVZFilter_calcCoeffs (tVZFilter* const vf)
{
_tVZFilter* f = *vf;
f->g = tanf(PI * f->fc * f->inv_sr); // embedded integrator gain (Fig 3.11)
switch( f->type )
{
case Bypass:
{
f->R2 = f->invG; // can we use an arbitrary value here, for example R2 = 1?
f->cL = 1.0f;
f->cB = f->R2;
f->cH = 1.0f;
}
break;
case Lowpass:
{
f->R2 = f->invG;
f->cL = 1.0f; f->cB = 0.0f; f->cH = 0.0f;
}
break;
case Highpass:
{
f->R2 = f->invG;
f->cL = 0.0f; f->cB = 0.0f; f->cH = 1.0f;
}
break;
case BandpassSkirt:
{
f->R2 = f->invG;
f->cL = 0.0f; f->cB = 1.0f; f->cH = 0.0f;
}
break;
case BandpassPeak:
{
f->R2 = 2.0f*tVZFilter_BandwidthToR(vf, f->B);
f->cL = 0.0f; f->cB = f->R2; f->cH = 0.0f;
}
break;
case BandReject:
{
f->R2 = 2.0f*tVZFilter_BandwidthToR(vf, f->B);
f->cL = 1.0f; f->cB = 0.0f; f->cH = 1.0f;
}
break;
case Bell:
{
float fl = f->fc*powf(2.0f, (-f->B)*0.5f); // lower bandedge frequency (in Hz)
float wl = tanf(PI*fl*f->inv_sr); // warped radian lower bandedge frequency /(2*fs)
float r = f->g/wl;
r *= r; // warped frequency ratio wu/wl == (wc/wl)^2 where wu is the
// warped upper bandedge, wc the center
f->R2 = 2.0f*sqrtf(((r*r+1.0f)/r-2.0f)/(4.0f*f->G));
f->cL = 1.0f; f->cB = f->R2*f->G; f->cH = 1.0f;
}
break;
case Lowshelf:
{
float A = sqrtf(f->G);
f->g /= sqrtf(A); // scale SVF-cutoff frequency for shelvers
f->R2 = 2*sinhf(f->B*logf(2.0f)*0.5f);
f->cL = f->G; f->cB = f->R2*A; f->cH = 1.0f;
}
break;
case Highshelf:
{
float A = sqrtf(f->G);
f->g *= sqrtf(A); // scale SVF-cutoff frequency for shelvers
f->R2 = 2.0f*sinhf(f->B*logf(2.0f)*0.5f);
f->cL = 1.0f; f->cB = f->R2*A; f->cH = f->G;
}
break;
case Allpass:
{
f->R2 = 2.0f*tVZFilter_BandwidthToR(vf, f->B);
f->cL = 1.0f; f->cB = -f->R2; f->cH = 1.0f;
}
break;
// experimental - maybe we must find better curves for cL, cB, cH:
case Morph:
{
f->R2 = f->invG;
float x = 2.0f*f->m-1.0f;
f->cL = maximum(-x, 0.0f); /*cL *= cL;*/
f->cH = minimum( x, 0.0f); /*cH *= cH;*/
f->cB = 1.0f-x*x;
// bottom line: we need to test different versions for how they feel when tweaking the
// morph parameter
// this scaling ensures constant magnitude at the cutoff point (we divide the coefficients by
// the magnitude response value at the cutoff frequency and scale back by the gain):
float s = f->G * sqrtf((f->R2*f->R2) / (f->cL*f->cL + f->cB*f->cB + f->cH*f->cH - 2.0f*f->cL*f->cH));
f->cL *= s; f->cB *= s; f->cH *= s;
}
break;
}
f->h = 1.0f / (1.0f + f->R2*f->g + f->g*f->g); // factor for feedback precomputation
}
void tVZFilter_setBandwidth (tVZFilter* const vf, float B)
{
_tVZFilter* f = *vf;
f->B = LEAF_clip(0.0f, B, 100.0f);
tVZFilter_calcCoeffs(vf);
}
void tVZFilter_setFreq (tVZFilter* const vf, float freq)
{
_tVZFilter* f = *vf;
f->fc = LEAF_clip(0.0f, freq, 0.5f*leaf.sampleRate);
tVZFilter_calcCoeffs(vf);
}
void tVZFilter_setGain (tVZFilter* const vf, float gain)
{
_tVZFilter* f = *vf;
f->G = LEAF_clip(0.000001f, gain, 100.0f);
f->invG = 1.0f/f->G;
tVZFilter_calcCoeffs(vf);
}
void tVZFilter_setMorph (tVZFilter* const vf, float morph)
{
_tVZFilter* f = *vf;
f->m = LEAF_clip(0.0f, morph, 1.0f);
tVZFilter_calcCoeffs(vf);
}
void tVZFilter_setType (tVZFilter* const vf, VZFilterType type)
{
_tVZFilter* f = *vf;
f->type = type;
tVZFilter_calcCoeffs(vf);
}
float tVZFilter_BandwidthToR(tVZFilter* const vf, float B)
{
_tVZFilter* f = *vf;
float fl = f->fc*powf(2.0f, -B*0.5f); // lower bandedge frequency (in Hz)
float gl = tanf(PI*fl*f->inv_sr); // warped radian lower bandedge frequency /(2*fs)
float r = gl/f->g; // ratio between warped lower bandedge- and center-frequencies
// unwarped: r = pow(2, -B/2) -> approximation for low
// center-frequencies
return sqrtf((1.0f-r*r)*(1.0f-r*r)/(4.0f*r*r));
}
void tDiodeFilter_init (tDiodeFilter* const vf, float cutoff, float resonance)
{
tDiodeFilter_initToPool(vf, cutoff, resonance, &leaf.mempool);
}
void tDiodeFilter_free (tDiodeFilter* const vf)
{
tDiodeFilter_freeFromPool(vf, &leaf.mempool);
}
void tDiodeFilter_initToPool (tDiodeFilter* const vf, float cutoff, float resonance, tMempool* const mp)
{
_tMempool* m = *mp;
_tDiodeFilter* f = *vf = (_tDiodeFilter*) mpool_alloc(sizeof(_tDiodeFilter), m);
// initialization (the resonance factor is between 0 and 8 according to the article)
f->f = tan(PI * cutoff/leaf.sampleRate);
f->r = (7.f * resonance + 0.5f);
f->Vt = 0.5f;
f->n = 1.836f;
f->zi = 0.0f; //previous input value
f->gamma = f->Vt*f->n;
f->s0 = 0.01f;
f->s1 = 0.02f;
f->s2 = 0.03f;
f->s3 = 0.04f;
f->g0inv = 1.f/(2.f*f->Vt);
f->g1inv = 1.f/(2.f*f->gamma);
f->g2inv = 1.f/(6.f*f->gamma);
}
void tDiodeFilter_freeFromPool (tDiodeFilter* const vf, tMempool* const mp)
{
_tMempool* m = *mp;
_tDiodeFilter* f = *vf = (_tDiodeFilter*) mpool_alloc(sizeof(_tDiodeFilter), m);
mpool_free(f, m);
}
float tanhXdX(float x)
{
float a = x*x;
// IIRC I got this as Pade-approx for tanh(sqrt(x))/sqrt(x)
return ((a + 105.0f)*a + 945.0f) / ((15.0f*a + 420.0f)*a + 945.0f);
}
float tDiodeFilter_tick (tDiodeFilter* const vf, float in)
{
_tDiodeFilter* f = *vf;
// the input x[n+1] is given by 'in', and x[n] by zi
// input with half delay
float ih = 0.5f * (in + f->zi);
// evaluate the non-linear factors
float t0 = f->f*tanhXdX((ih - f->r * f->s3)*f->g0inv)*f->g0inv;
float t1 = f->f*tanhXdX((f->s1-f->s0)*f->g1inv)*f->g1inv;
float t2 = f->f*tanhXdX((f->s2-f->s1)*f->g1inv)*f->g1inv;
float t3 = f->f*tanhXdX((f->s3-f->s2)*f->g1inv)*f->g1inv;
float t4 = f->f*tanhXdX((f->s3)*f->g2inv)*f->g2inv;
// This formula gives the result for y3 thanks to MATLAB
float y3 = (f->s2 + f->s3 + t2*(f->s1 + f->s2 + f->s3 + t1*(f->s0 + f->s1 + f->s2 + f->s3 + t0*in)) + t1*(2.0f*f->s2 + 2.0f*f->s3))*t3 + f->s3 + 2.0f*f->s3*t1 + t2*(2.0f*f->s3 + 3.0f*f->s3*t1);
if (isnan(y3))
{
__HAL_TIM_SET_COMPARE(&htim3, TIM_CHANNEL_2, 400);
}
float tempy3denom = (t4 + t1*(2.0f*t4 + 4.0f) + t2*(t4 + t1*(t4 + f->r*t0 + 4.0f) + 3.0f) + 2.0f)*t3 + t4 + t1*(2.0f*t4 + 2.0f) + t2*(2.0f*t4 + t1*(3.0f*t4 + 3.0f) + 2.0f) + 1.0f;
if (isnan(tempy3denom))
{
__HAL_TIM_SET_COMPARE(&htim3, TIM_CHANNEL_2, 400);
}
if (tempy3denom == 0.0f)
{
tempy3denom = 0.000001f;
}
y3 = y3 / tempy3denom;
if (isnan(y3))
{
__HAL_TIM_SET_COMPARE(&htim3, TIM_CHANNEL_2, 400);
}
if (t1 == 0.0f)
{
t1 = 0.000001f;
}
if (t2 == 0.0f)
{
t2 = 0.000001f;
}
if (t3 == 0.0f)
{
t3 = 0.000001f;
}
// Other outputs
float y2 = (f->s3 - (1+t4+t3)*y3) / (-t3);
float y1 = (f->s2 - (1+t3+t2)*y2 + t3*y3) / (-t2);
float y0 = (f->s1 - (1+t2+t1)*y1 + t2*y2) / (-t1);
float xx = (in - f->r*y3);
// update state
f->s0 += 2.0f * (t0*xx + t1*(y1-y0));
if (isnan(f->s0))
{
__HAL_TIM_SET_COMPARE(&htim3, TIM_CHANNEL_2, 400);
}
if (isinf(f->s0))
{
__HAL_TIM_SET_COMPARE(&htim3, TIM_CHANNEL_2, 400);
}
f->s1 += 2.0f * (t2*(y2-y1) - t1*(y1-y0));
f->s2 += 2.0f * (t3*(y3-y2) - t2*(y2-y1));
f->s3 += 2.0f * (-t4*(y3) - t3*(y3-y2));
f->zi = in;
return y3*f->r;
}
void tDiodeFilter_setFreq (tDiodeFilter* const vf, float cutoff)
{
_tDiodeFilter* f = *vf;
f->f = tanf(PI * LEAF_clip(10.0f, cutoff, 20000.0f)*leaf.invSampleRate);
}
void tDiodeFilter_setQ (tDiodeFilter* const vf, float resonance)
{
_tDiodeFilter* f = *vf;
f->r = LEAF_clip(0.5, (7.f * resonance + 0.5f), 8.0f);
}