/* ----- key on ----- */
void OPL_KEYON(OPL_SLOT SLOT)
{
/* sin wave restart */
SLOT.Cnt = 0;
/* set attack */
SLOT.evm = ENV_MOD_AR;
SLOT.evs = SLOT.evsa;
SLOT.evc = EG_AST;
SLOT.eve = EG_AED;
}
/* set multi,am,vib,EG-TYP,KSR,mul */
void set_mul(int slot,int v)
{
OPL_CH CH = P_CH[slot >> 1];
OPL_SLOT SLOT = CH.SLOT[slot & 1];
SLOT.mul = MUL_TABLE[v & 0x0f];
SLOT.KSR = (v & 0x10) != 0 ? (byte)0 : (byte)2;
SLOT.eg_typ = (byte)((v & 0x20) >> 5);
SLOT.vib = (byte)(v & 0x40);
SLOT.ams = (byte)(v & 0x80);
CALC_FCSLOT(CH,SLOT);
}
/* set ksl & tl */
void set_ksl_tl(int slot,int v)
{
OPL_CH CH = P_CH[slot >> 1];
OPL_SLOT SLOT = CH.SLOT[slot & 1];
int ksl = v >> 6; /* 0 / 1.5 / 3 / 6 db/OCT */
SLOT.ksl = ksl != 0 ? (byte)(3 - ksl) : (byte)31;
SLOT.TL = (int)((v & 0x3f) * (0.75 / EG_STEP())); /* 0.75db step */
if ((mode & 0x80) == 0)
{ /* not CSM latch total level */
SLOT.TLL = (int)(SLOT.TL + (CH.ksl_base >> SLOT.ksl));
}
}
/* ----- key off ----- */
void OPL_KEYOFF(OPL_SLOT SLOT)
{
if (SLOT.evm > ENV_MOD_RR)
{
/* set envelope counter from envleope output */
// WORKAROUND: The Kyra engine does something very strange when
// starting a new song. For each channel:
//
// * The release rate is set to "fastest".
// * Any note is keyed off.
// * A very low-frequency note is keyed on.
//
// Usually, what happens next is that the real notes is keyed
// on immediately, in which case there's no problem.
//
// However, if the note is again keyed off (because the channel
// begins on a rest rather than a note), the envelope counter
// was moved from the very lowest point on the attack curve to
// the very highest point on the release curve.
//
// Again, this might not be a problem, if the release rate is
// still set to "fastest". But in many cases, it had already
// been increased. And, possibly because of inaccuracies in the
// envelope generator, that would cause the note to "fade out"
// for quite a long time.
//
// What we really need is a way to find the correct starting
// point for the envelope counter, and that may be what the
// commented-out line below is meant to do. For now, simply
// handle the pathological case.
if (SLOT.evm == ENV_MOD_AR && SLOT.evc == EG_AST)
{
SLOT.evc = EG_DED;
}
else if ((SLOT.evc & EG_DST) == 0)
{
//SLOT.evc = (ENV_CURVE[SLOT.evc>>ENV_BITS]<<ENV_BITS) + EG_DST;
SLOT.evc = EG_DST;
}
SLOT.eve = EG_DED;
SLOT.evs = SLOT.evsr;
SLOT.evm = ENV_MOD_RR;
}
}
/* ---------- frequency counter for operater update ---------- */
void CALC_FCSLOT(OPL_CH CH,OPL_SLOT SLOT)
{
int ksr;
/* frequency step counter */
SLOT.Incr = CH.fc * SLOT.mul;
ksr = CH.kcode >> SLOT.KSR;
if (SLOT.ksr != ksr)
{
SLOT.ksr = (byte)ksr;
/* attack , decay rate recalcration */
SLOT.evsa = SLOT.AR(ksr);
SLOT.evsd = SLOT.DR(ksr);
SLOT.evsr = SLOT.RR(ksr);
}
SLOT.TLL = (int)(SLOT.TL + (CH.ksl_base >> SLOT.ksl));
}
/* set sustain level & release rate */
void set_sl_rr(int slot,int v)
{
OPL_CH CH = P_CH[slot >> 1];
OPL_SLOT SLOT = CH.SLOT[slot & 1];
int sl = v >> 4;
int rr = v & 0x0f;
SLOT.SL = SL_TABLE[sl];
if (SLOT.evm == ENV_MOD_DR)
{
SLOT.eve = SLOT.SL;
}
SLOT.RR = new Func <int,int>(index => DR_TABLE[index + rr << 2]);
SLOT.evsr = SLOT.RR(SLOT.ksr);
if (SLOT.evm == ENV_MOD_RR)
{
SLOT.evs = SLOT.evsr;
}
}
/* set attack rate & decay rate */
void set_ar_dr(int slot,int v)
{
OPL_CH CH = P_CH[slot >> 1];
OPL_SLOT SLOT = CH.SLOT[slot & 1];
int ar = v >> 4;
int dr = v & 0x0f;
SLOT.AR = ar != 0 ? new Func <int,int>(index => AR_TABLE[index + ar << 2]) : RATE_0;
SLOT.evsa = SLOT.AR(SLOT.ksr);
if (SLOT.evm == ENV_MOD_AR)
{
SLOT.evs = SLOT.evsa;
}
SLOT.DR = dr != 0 ? new Func <int,int>(index => DR_TABLE[index + dr << 2]) : RATE_0;
SLOT.evsd = SLOT.DR(SLOT.ksr);
if (SLOT.evm == ENV_MOD_DR)
{
SLOT.evs = SLOT.evsd;
}
}
/* return : envelope output */
uint OPL_CALC_SLOT(OPL_SLOT SLOT)
{
/* calcrate envelope generator */
if ((SLOT.evc += SLOT.evs) >= SLOT.eve)
{
switch (SLOT.evm)
{
case ENV_MOD_AR: /* ATTACK . DECAY1 */
/* next DR */
SLOT.evm = ENV_MOD_DR;
SLOT.evc = EG_DST;
SLOT.eve = SLOT.SL;
SLOT.evs = SLOT.evsd;
break;
case ENV_MOD_DR: /* DECAY . SL or RR */
SLOT.evc = SLOT.SL;
SLOT.eve = EG_DED;
if (SLOT.eg_typ)
{
SLOT.evs = 0;
}
else
{
SLOT.evm = ENV_MOD_RR;
SLOT.evs = SLOT.evsr;
}
break;
case ENV_MOD_RR: /* RR . OFF */
SLOT.evc = EG_OFF;
SLOT.eve = EG_OFF + 1;
SLOT.evs = 0;
break;
}
}
/* calcrate envelope */
return(SLOT.TLL + ENV_CURVE[SLOT.evc >> ENV_BITS] + (SLOT.ams ? ams : 0));
}
/* ----- key off ----- */
void OPL_KEYOFF(OPL_SLOT SLOT)
{
if (SLOT.evm > ENV_MOD_RR)
{
/* set envelope counter from envleope output */
// WORKAROUND: The Kyra engine does something very strange when
// starting a new song. For each channel:
//
// * The release rate is set to "fastest".
// * Any note is keyed off.
// * A very low-frequency note is keyed on.
//
// Usually, what happens next is that the real notes is keyed
// on immediately, in which case there's no problem.
//
// However, if the note is again keyed off (because the channel
// begins on a rest rather than a note), the envelope counter
// was moved from the very lowest point on the attack curve to
// the very highest point on the release curve.
//
// Again, this might not be a problem, if the release rate is
// still set to "fastest". But in many cases, it had already
// been increased. And, possibly because of inaccuracies in the
// envelope generator, that would cause the note to "fade out"
// for quite a long time.
//
// What we really need is a way to find the correct starting
// point for the envelope counter, and that may be what the
// commented-out line below is meant to do. For now, simply
// handle the pathological case.
if (SLOT.evm == ENV_MOD_AR && SLOT.evc == EG_AST)
SLOT.evc = EG_DED;
else if ((SLOT.evc & EG_DST) == 0)
//SLOT.evc = (ENV_CURVE[SLOT.evc>>ENV_BITS]<<ENV_BITS) + EG_DST;
SLOT.evc = EG_DST;
SLOT.eve = EG_DED;
SLOT.evs = SLOT.evsr;
SLOT.evm = ENV_MOD_RR;
}
}
/* ----- key on ----- */
void OPL_KEYON(OPL_SLOT SLOT)
{
/* sin wave restart */
SLOT.Cnt = 0;
/* set attack */
SLOT.evm = ENV_MOD_AR;
SLOT.evs = SLOT.evsa;
SLOT.evc = EG_AST;
SLOT.eve = EG_AED;
}
/* return : envelope output */
uint OPL_CALC_SLOT(OPL_SLOT SLOT)
{
/* calcrate envelope generator */
if ((SLOT.evc += SLOT.evs) >= SLOT.eve)
{
switch (SLOT.evm)
{
case ENV_MOD_AR: /* ATTACK . DECAY1 */
/* next DR */
SLOT.evm = ENV_MOD_DR;
SLOT.evc = EG_DST;
SLOT.eve = SLOT.SL;
SLOT.evs = SLOT.evsd;
break;
case ENV_MOD_DR: /* DECAY . SL or RR */
SLOT.evc = SLOT.SL;
SLOT.eve = EG_DED;
if (SLOT.eg_typ)
{
SLOT.evs = 0;
}
else
{
SLOT.evm = ENV_MOD_RR;
SLOT.evs = SLOT.evsr;
}
break;
case ENV_MOD_RR: /* RR . OFF */
SLOT.evc = EG_OFF;
SLOT.eve = EG_OFF + 1;
SLOT.evs = 0;
break;
}
}
/* calcrate envelope */
return SLOT.TLL + ENV_CURVE[SLOT.evc >> ENV_BITS] + (SLOT.ams ? ams : 0);
}
/* ---------- frequency counter for operater update ---------- */
void CALC_FCSLOT(OPL_CH CH, OPL_SLOT SLOT)
{
int ksr;
/* frequency step counter */
SLOT.Incr = CH.fc * SLOT.mul;
ksr = CH.kcode >> SLOT.KSR;
if (SLOT.ksr != ksr)
{
SLOT.ksr = (byte)ksr;
/* attack , decay rate recalcration */
SLOT.evsa = SLOT.AR(ksr);
SLOT.evsd = SLOT.DR(ksr);
SLOT.evsr = SLOT.RR(ksr);
}
SLOT.TLL = (int)(SLOT.TL + (CH.ksl_base >> SLOT.ksl));
}