void LPF18_next(LPF18 *unit, int nsmps)
{
float *in = ZIN(0);
float *out = ZOUT(0);
float fco = ZIN0(1);
float res = ZIN0(2);
float dist = ZIN0(3);
float aout = unit->aout;
float ay1 = unit->ay1;
float ay2 = unit->ay2;
float lastin = unit->lastin;
float kfcn, kp = unit->kp;
float kp1, kp1h;
if (fco != unit->last_fco) {
kfcn = 2.0f * unit->last_fco * SAMPLEDUR;
kp1 = kp+1.0f;
kp1h = 0.5f*kp1;
float newkfcn = 2.0f * fco * SAMPLEDUR;
float newkp = ((-2.7528f*newkfcn + 3.0429f)*newkfcn +
1.718f)*newkfcn - 0.9984f;
float newkp1 = kp+1.0f;
float newkp1h = 0.5f*kp1;
float kp1hinc = (newkp1h-kp1h)/nsmps;
float kpinc = (newkp-kp)/nsmps;
float kres = unit->kres;
float newkres = res * (((-2.7079f*newkp1 + 10.963f)*newkp1
- 14.934f)*newkp1 + 8.4974f);
float kresinc = (newkres-kres)/nsmps;
float value = unit->m_value;
float newvalue = 1.0f+(dist*(1.5f+2.0f*newkres*(1.0f-newkfcn)));
float valueinc = (newvalue-value)/nsmps;
unit->kp = newkp;
unit->m_value = newvalue;
unit->kres = newkres;
unit->last_fco = fco;
LOOP(nsmps,
float ax1 = lastin;
float ay11 = ay1;
float ay31 = ay2;
lastin = ZXP(in) - TANH(kres*aout);
ay1 = kp1h * (lastin + ax1) - kp*ay1;
ay2 = kp1h * (ay1 + ay11) - kp*ay2;
aout = kp1h * (ay2 + ay31) - kp*aout;
ZXP(out) = TANH(aout*value);
kp1h += kp1hinc;
kp += kpinc;
kres += kresinc;
value += valueinc;
);
single XTANH( single *arg ) {
//===========================
return( TANH( *arg ) );
}
static int32_t nlfilt2(CSOUND *csound, NLFILT *p)
{
MYFLT *ar;
uint32_t offset = p->h.insdshead->ksmps_offset;
uint32_t early = p->h.insdshead->ksmps_no_end;
uint32_t n, nsmps = CS_KSMPS;
int32_t point = p->point;
int32_t nm1 = point;
int32_t nm2 = point - 1;
int32_t nmL;
MYFLT ynm1, ynm2, ynmL;
MYFLT a = *p->a, b = *p->b, d = *p->d, C = *p->C;
MYFLT *in = p->in;
MYFLT *fp = (MYFLT*) p->delay.auxp;
MYFLT L = *p->L;
MYFLT maxamp, dvmaxamp, maxampd2;
if (UNLIKELY(fp == NULL)) goto err1; /* RWD fix */
ar = p->ar;
/* L is k-rate so need to check */
if (L < FL(1.0))
L = FL(1.0);
else if (L >= MAX_DELAY) {
L = (MYFLT) MAX_DELAY;
}
nmL = point - (int32_t) (L) - 1;
if (UNLIKELY(nm1 < 0)) nm1 += MAX_DELAY; /* Deal with the wrapping */
if (UNLIKELY(nm2 < 0)) nm2 += MAX_DELAY;
if (UNLIKELY(nmL < 0)) nmL += MAX_DELAY;
ynm1 = fp[nm1]; /* Pick up running values */
ynm2 = fp[nm2];
ynmL = fp[nmL];
nsmps = CS_KSMPS;
maxamp = csound->e0dbfs * FL(1.953125); /* 64000 with default 0dBFS */
dvmaxamp = FL(1.0) / maxamp;
maxampd2 = maxamp * FL(0.5);
if (UNLIKELY(offset)) memset(ar, '\0', offset*sizeof(MYFLT));
if (UNLIKELY(early)) {
nsmps -= early;
memset(&ar[nsmps], '\0', early*sizeof(MYFLT));
}
for (n=offset; n<nsmps; n++) {
MYFLT yn;
MYFLT out;
yn = a * ynm1 + b * ynm2 + d * ynmL * ynmL - C;
yn += in[n] * dvmaxamp; /* Must work in small amplitudes */
out = yn * maxampd2; /* Write output */
if (out > maxamp)
out = maxampd2;
else if (out < -maxamp)
out = -maxampd2;
ar[n] = out;
if (UNLIKELY(++point == MAX_DELAY)) {
point = 0;
}
yn = TANH(yn);
fp[point] = yn; /* and delay line */
if (UNLIKELY(++nmL == MAX_DELAY)) {
nmL = 0;
}
ynm2 = ynm1; /* Shuffle along */
ynm1 = yn;
ynmL = fp[nmL];
}
p->point = point;
return OK;
err1:
return csound->PerfError(csound, &(p->h),
Str("nlfilt2: not initialised"));
} /* end nlfilt2(p) */
