void TVA::recalcSustain() {
// We get pinged periodically by the pitch code to recalculate our values when in sustain.
// This is done so that the TVA will respond to things like MIDI expression and volume changes while it's sustaining, which it otherwise wouldn't do.
// The check for envLevel[3] == 0 strikes me as slightly dumb. FIXME: Explain why
if (phase != TVA_PHASE_SUSTAIN || partialParam->tva.envLevel[3] == 0) {
return;
}
// We're sustaining. Recalculate all the values
const Tables *tables = &Tables::getInstance();
int newTarget = calcBasicAmp(tables, partial, system, partialParam, patchTemp, rhythmTemp, biasAmpSubtraction, veloAmpSubtraction, part->getExpression(), partial->getSynth()->controlROMFeatures->quirkRingModulationNoMix);
newTarget += partialParam->tva.envLevel[3];
// Although we're in TVA_PHASE_SUSTAIN at this point, we cannot be sure that there is no active ramp at the moment.
// In case the channel volume or the expression changes frequently, the previously started ramp may still be in progress.
// Real hardware units ignore this possibility and rely on the assumption that the target is the current amp.
// This is OK in most situations but when the ramp that is currently in progress needs to change direction
// due to a volume/expression update, this leads to a jump in the amp that is audible as an unpleasant click.
// To avoid that, we compare the newTarget with the the actual current ramp value and correct the direction if necessary.
int targetDelta = newTarget - target;
// Calculate an increment to get to the new amp value in a short, more or less consistent amount of time
Bit8u newIncrement;
bool descending = targetDelta < 0;
if (!descending) {
newIncrement = tables->envLogarithmicTime[Bit8u(targetDelta)] - 2;
} else {
newIncrement = (tables->envLogarithmicTime[Bit8u(-targetDelta)] - 2) | 0x80;
}
if (part->getSynth()->isNiceAmpRampEnabled() && (descending != ampRamp->isBelowCurrent(newTarget))) {
newIncrement ^= 0x80;
}
// Configure so that once the transition's complete and nextPhase() is called, we'll just re-enter sustain phase (or decay phase, depending on parameters at the time).
startRamp(newTarget, newIncrement, TVA_PHASE_SUSTAIN - 1);
}
void TVA::reset(const Part *newPart, const TimbreParam::PartialParam *newPartialParam, const MemParams::RhythmTemp *newRhythmTemp) {
part = newPart;
partialParam = newPartialParam;
patchTemp = newPart->getPatchTemp();
rhythmTemp = newRhythmTemp;
playing = true;
const Tables *tables = &Tables::getInstance();
int key = partial->getPoly()->getKey();
int velocity = partial->getPoly()->getVelocity();
keyTimeSubtraction = calcKeyTimeSubtraction(partialParam->tva.envTimeKeyfollow, key);
biasAmpSubtraction = calcBiasAmpSubtractions(partialParam, key);
veloAmpSubtraction = calcVeloAmpSubtraction(partialParam->tva.veloSensitivity, velocity);
int newTarget = calcBasicAmp(tables, partial, system, partialParam, patchTemp, newRhythmTemp, biasAmpSubtraction, veloAmpSubtraction, part->getExpression(), partial->getSynth()->controlROMFeatures->quirkRingModulationNoMix);
int newPhase;
if (partialParam->tva.envTime[0] == 0) {
// Initially go to the TVA_PHASE_ATTACK target amp, and spend the next phase going from there to the TVA_PHASE_2 target amp
// Note that this means that velocity never affects time for this partial.
newTarget += partialParam->tva.envLevel[0];
newPhase = TVA_PHASE_ATTACK; // The first target used in nextPhase() will be TVA_PHASE_2
} else {
// Initially go to the base amp determined by TVA level, part volume, etc., and spend the next phase going from there to the full TVA_PHASE_ATTACK target amp.
newPhase = TVA_PHASE_BASIC; // The first target used in nextPhase() will be TVA_PHASE_ATTACK
}
ampRamp->reset();//currentAmp = 0;
// "Go downward as quickly as possible".
// Since the current value is 0, the LA32Ramp will notice that we're already at or below the target and trying to go downward,
// and therefore jump to the target immediately and raise an interrupt.
startRamp(Bit8u(newTarget), 0x80 | 127, newPhase);
}
static bool isvalid(const char in) {
const char ill[]=ILLEGAL;
return (Bit8u(in)>0x1F) && (!strchr(ill,in));
}
static bool isvalid(const char in)
{
return (Bit8u(in) > 0x1F) && (!strchr(":.;,=+ \t/\"[]<>|", in));
}
Tables::Tables() {
for (int lf = 0; lf <= 100; lf++) {
// CONFIRMED:KG: This matches a ROM table found by Mok
float fVal = (2.0f - LOG10F(float(lf) + 1.0f)) * 128.0f;
int val = int(fVal + 1.0);
if (val > 255) {
val = 255;
}
levelToAmpSubtraction[lf] = Bit8u(val);
}
envLogarithmicTime[0] = 64;
for (int lf = 1; lf <= 255; lf++) {
// CONFIRMED:KG: This matches a ROM table found by Mok
envLogarithmicTime[lf] = Bit8u(ceil(64.0f + LOG2F(float(lf)) * 8.0f));
}
#if 0
// The table below is to be used in conjunction with emulation of VCA of newer generation units which is currently missing.
// These relatively small values are rather intended to fine-tune the overall amplification of the VCA.
// CONFIRMED: Based on a table found by Mok in the LAPC-I control ROM
// Note that this matches the MT-32 table, but with the values clamped to a maximum of 8.
memset(masterVolToAmpSubtraction, 8, 71);
memset(masterVolToAmpSubtraction + 71, 7, 3);
memset(masterVolToAmpSubtraction + 74, 6, 4);
memset(masterVolToAmpSubtraction + 78, 5, 3);
memset(masterVolToAmpSubtraction + 81, 4, 4);
memset(masterVolToAmpSubtraction + 85, 3, 3);
memset(masterVolToAmpSubtraction + 88, 2, 4);
memset(masterVolToAmpSubtraction + 92, 1, 4);
memset(masterVolToAmpSubtraction + 96, 0, 5);
#else
// CONFIRMED: Based on a table found by Mok in the MT-32 control ROM
masterVolToAmpSubtraction[0] = 255;
for (int masterVol = 1; masterVol <= 100; masterVol++) {
masterVolToAmpSubtraction[masterVol] = Bit8u(106.31 - 16.0f * LOG2F(float(masterVol)));
}
#endif
for (int i = 0; i <= 100; i++) {
pulseWidth100To255[i] = Bit8u(i * 255 / 100.0f + 0.5f);
//synth->printDebug("%d: %d", i, pulseWidth100To255[i]);
}
// The LA32 chip contains an exponent table inside. The table contains 12-bit integer values.
// The actual table size is 512 rows. The 9 higher bits of the fractional part of the argument are used as a lookup address.
// To improve the precision of computations, the lower bits are supposed to be used for interpolation as the LA32 chip also
// contains another 512-row table with inverted differences between the main table values.
for (int i = 0; i < 512; i++) {
exp9[i] = Bit16u(8191.5f - EXP2F(13.0f + ~i / 512.0f));
}
// There is a logarithmic sine table inside the LA32 chip. The table contains 13-bit integer values.
for (int i = 1; i < 512; i++) {
logsin9[i] = Bit16u(0.5f - LOG2F(sin((i + 0.5f) / 1024.0f * FLOAT_PI)) * 1024.0f);
}
// The very first value is clamped to the maximum possible 13-bit integer
logsin9[0] = 8191;
// found from sample analysis
static const Bit8u resAmpDecayFactorTable[] = {31, 16, 12, 8, 5, 3, 2, 1};
resAmpDecayFactor = resAmpDecayFactorTable;
}
