ref: 19a991d12e072f63f39deaa24ae083d6ca417b71
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"
#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_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;
}
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);
}
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);
}
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 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);
}
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);
}
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);
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 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_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);
}
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) );
}
}
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 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_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);
}
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;
}
}
/* 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_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));
}
// 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;
float a1,a2,a3,g,k;
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 = g*a1;
svf->a3 = g*a2;
}
void tSVF_free(tSVF* const svff)
{
_tSVF* svf = *svff;
leaf_free(svf);
}
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;
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 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;
}
// 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;
float a1,a2,a3,g,k;
svf->g = filtertan[input];
svf->k = 1.0f/Q;
svf->a1 = 1.0f/(1.0f+g*(g+k));
svf->a2 = g*a1;
svf->a3 = g*a2;
}
void tEfficientSVF_free(tEfficientSVF* const svff)
{
_tEfficientSVF* svf = *svff;
leaf_free(svf);
}
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 = 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;
}
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;
}
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;
}
void tFIR_free(tFIR* const firf)
{
_tFIR* fir = *firf;
leaf_free(fir->past);
leaf_free(fir);
}