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