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/* Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009 Dean Beeler, Jerome Fisher
* Copyright (C) 2011, 2012, 2013 Dean Beeler, Jerome Fisher, Sergey V. Mikayev
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//#include <cmath>
#include "mt32emu.h"
#include "mmath.h"
namespace MT32Emu {
// Note that when entering nextPhase(), newPhase is set to phase + 1, and the descriptions/names below refer to
// newPhase's value.
enum {
// When this is the target phase, level[0] is targeted within time[0]
// Note that this phase is always set up in reset(), not nextPhase()
PHASE_ATTACK = 1,
// When this is the target phase, level[1] is targeted within time[1]
PHASE_2 = 2,
// When this is the target phase, level[2] is targeted within time[2]
PHASE_3 = 3,
// When this is the target phase, level[3] is targeted within time[3]
PHASE_4 = 4,
// When this is the target phase, immediately goes to PHASE_RELEASE unless the poly is set to sustain.
// Otherwise level[3] is continued with increment 0 - no phase change will occur until some external influence (like pedal release)
PHASE_SUSTAIN = 5,
// 0 is targeted within time[4] (the time calculation is quite different from the other phases)
PHASE_RELEASE = 6,
// 0 is targeted with increment 0 (thus theoretically staying that way forever)
PHASE_DONE = 7
};
static int calcBaseCutoff(const TimbreParam::PartialParam *partialParam, Bit32u basePitch, unsigned int key) {
// This table matches the values used by a real LAPC-I.
static const Bit8s biasLevelToBiasMult[] = {85, 42, 21, 16, 10, 5, 2, 0, -2, -5, -10, -16, -21, -74, -85};
// These values represent unique options with no consistent pattern, so we have to use something like a table in any case.
// The table entries, when divided by 21, match approximately what the manual claims:
// -1, -1/2, -1/4, 0, 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, 1, 5/4, 3/2, 2, s1, s2
// Note that the entry for 1/8 is rounded to 2 (from 1/8 * 21 = 2.625), which seems strangely inaccurate compared to the others.
static const Bit8s keyfollowMult21[] = {-21, -10, -5, 0, 2, 5, 8, 10, 13, 16, 18, 21, 26, 32, 42, 21, 21};
int baseCutoff = keyfollowMult21[partialParam->tvf.keyfollow] - keyfollowMult21[partialParam->wg.pitchKeyfollow];
// baseCutoff range now: -63 to 63
baseCutoff *= (int)key - 60;
// baseCutoff range now: -3024 to 3024
int biasPoint = partialParam->tvf.biasPoint;
if ((biasPoint & 0x40) == 0) {
// biasPoint range here: 0 to 63
int bias = biasPoint + 33 - key; // bias range here: -75 to 84
if (bias > 0) {
bias = -bias; // bias range here: -1 to -84
baseCutoff += bias * biasLevelToBiasMult[partialParam->tvf.biasLevel]; // Calculation range: -7140 to 7140
// baseCutoff range now: -10164 to 10164
}
} else {
// biasPoint range here: 64 to 127
int bias = biasPoint - 31 - key; // bias range here: -75 to 84
if (bias < 0) {
baseCutoff += bias * biasLevelToBiasMult[partialParam->tvf.biasLevel]; // Calculation range: −6375 to 6375
// baseCutoff range now: -9399 to 9399
}
}
// baseCutoff range now: -10164 to 10164
baseCutoff += ((partialParam->tvf.cutoff << 4) - 800);
// baseCutoff range now: -10964 to 10964
if (baseCutoff >= 0) {
// FIXME: Potentially bad if baseCutoff ends up below -2056?
int pitchDeltaThing = (basePitch >> 4) + baseCutoff - 3584;
if (pitchDeltaThing > 0) {
baseCutoff -= pitchDeltaThing;
}
} else if (baseCutoff < -2048) {
baseCutoff = -2048;
}
baseCutoff += 2056;
baseCutoff >>= 4; // PORTABILITY NOTE: Hmm... Depends whether it could've been below -2056, but maybe arithmetic shift assumed?
if (baseCutoff > 255) {
baseCutoff = 255;
}
return (Bit8u)baseCutoff;
}
TVF::TVF(const Partial *usePartial, LA32Ramp *useCutoffModifierRamp) :
partial(usePartial), cutoffModifierRamp(useCutoffModifierRamp) {
}
void TVF::startRamp(Bit8u newTarget, Bit8u newIncrement, int newPhase) {
target = newTarget;
phase = newPhase;
cutoffModifierRamp->startRamp(newTarget, newIncrement);
#if MT32EMU_MONITOR_TVF >= 1
partial->getSynth()->printDebug("[+%lu] [Partial %d] TVF,ramp,%d,%d,%d,%d", partial->debugGetSampleNum(), partial->debugGetPartialNum(), newTarget, (newIncrement & 0x80) ? -1 : 1, (newIncrement & 0x7F), newPhase);
#endif
}
void TVF::reset(const TimbreParam::PartialParam *newPartialParam, unsigned int basePitch) {
partialParam = newPartialParam;
unsigned int key = partial->getPoly()->getKey();
unsigned int velocity = partial->getPoly()->getVelocity();
const Tables *tables = &Tables::getInstance();
baseCutoff = calcBaseCutoff(newPartialParam, basePitch, key);
#if MT32EMU_MONITOR_TVF >= 1
partial->getSynth()->printDebug("[+%lu] [Partial %d] TVF,base,%d", partial->debugGetSampleNum(), partial->debugGetPartialNum(), baseCutoff);
#endif
int newLevelMult = velocity * newPartialParam->tvf.envVeloSensitivity;
newLevelMult >>= 6;
newLevelMult += 109 - newPartialParam->tvf.envVeloSensitivity;
newLevelMult += ((signed)key - 60) >> (4 - newPartialParam->tvf.envDepthKeyfollow);
if (newLevelMult < 0) {
newLevelMult = 0;
}
newLevelMult *= newPartialParam->tvf.envDepth;
newLevelMult >>= 6;
if (newLevelMult > 255) {
newLevelMult = 255;
}
levelMult = newLevelMult;
if (newPartialParam->tvf.envTimeKeyfollow != 0) {
keyTimeSubtraction = ((signed)key - 60) >> (5 - newPartialParam->tvf.envTimeKeyfollow);
} else {
keyTimeSubtraction = 0;
}
int newTarget = (newLevelMult * newPartialParam->tvf.envLevel[0]) >> 8;
int envTimeSetting = newPartialParam->tvf.envTime[0] - keyTimeSubtraction;
int newIncrement;
if (envTimeSetting <= 0) {
newIncrement = (0x80 | 127);
} else {
newIncrement = tables->envLogarithmicTime[newTarget] - envTimeSetting;
if (newIncrement <= 0) {
newIncrement = 1;
}
}
cutoffModifierRamp->reset();
startRamp(newTarget, newIncrement, PHASE_2 - 1);
}
Bit8u TVF::getBaseCutoff() const {
return baseCutoff;
}
void TVF::handleInterrupt() {
nextPhase();
}
void TVF::startDecay() {
if (phase >= PHASE_RELEASE) {
return;
}
if (partialParam->tvf.envTime[4] == 0) {
startRamp(0, 1, PHASE_DONE - 1);
} else {
startRamp(0, -partialParam->tvf.envTime[4], PHASE_DONE - 1);
}
}
void TVF::nextPhase() {
const Tables *tables = &Tables::getInstance();
int newPhase = phase + 1;
switch (newPhase) {
case PHASE_DONE:
startRamp(0, 0, newPhase);
return;
case PHASE_SUSTAIN:
case PHASE_RELEASE:
// FIXME: Afaict newPhase should never be PHASE_RELEASE here. And if it were, this is an odd way to handle it.
if (!partial->getPoly()->canSustain()) {
phase = newPhase; // FIXME: Correct?
startDecay(); // FIXME: This should actually start decay even if phase is already 6. Does that matter?
return;
}
startRamp((levelMult * partialParam->tvf.envLevel[3]) >> 8, 0, newPhase);
return;
}
int envPointIndex = phase;
int envTimeSetting = partialParam->tvf.envTime[envPointIndex] - keyTimeSubtraction;
int newTarget = (levelMult * partialParam->tvf.envLevel[envPointIndex]) >> 8;
int newIncrement;
if (envTimeSetting > 0) {
int targetDelta = newTarget - target;
if (targetDelta == 0) {
if (newTarget == 0) {
targetDelta = 1;
newTarget = 1;
} else {
targetDelta = -1;
newTarget--;
}
}
newIncrement = tables->envLogarithmicTime[targetDelta < 0 ? -targetDelta : targetDelta] - envTimeSetting;
if (newIncrement <= 0) {
newIncrement = 1;
}
if (targetDelta < 0) {
newIncrement |= 0x80;
}
} else {
newIncrement = newTarget >= target ? (0x80 | 127) : 127;
}
startRamp(newTarget, newIncrement, newPhase);
}
}
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