/[svn]/linuxsampler/trunk/src/engines/gig/EGADSR.cpp
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Annotation of /linuxsampler/trunk/src/engines/gig/EGADSR.cpp

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Revision 53 - (hide annotations) (download)
Mon Apr 26 17:15:51 2004 UTC (19 years, 11 months ago) by schoenebeck
File size: 12720 byte(s)
* completely restructured source tree
* implemented multi channel support
* implemented instrument manager, which controls sharing of instruments
  between multiple sampler engines / sampler channels
* created abstract classes 'AudioOutputDevice' and 'MidiInputDevice' for
  convenient implementation of further audio output driver and MIDI input
  driver for LinuxSampler
* implemented following LSCP commands: 'SET CHANNEL MIDI INPUT TYPE',
  'LOAD ENGINE', 'GET CHANNELS', 'ADD CHANNEL', 'REMOVE CHANNEL',
  'SET CHANNEL AUDIO OUTPUT TYPE'
* temporarily removed all command line options
* LSCP server is now launched by default

1 schoenebeck 53 /***************************************************************************
2     * *
3     * LinuxSampler - modular, streaming capable sampler *
4     * *
5     * Copyright (C) 2003 by Benno Senoner and Christian Schoenebeck *
6     * *
7     * This program is free software; you can redistribute it and/or modify *
8     * it under the terms of the GNU General Public License as published by *
9     * the Free Software Foundation; either version 2 of the License, or *
10     * (at your option) any later version. *
11     * *
12     * This program is distributed in the hope that it will be useful, *
13     * but WITHOUT ANY WARRANTY; without even the implied warranty of *
14     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
15     * GNU General Public License for more details. *
16     * *
17     * You should have received a copy of the GNU General Public License *
18     * along with this program; if not, write to the Free Software *
19     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
20     * MA 02111-1307 USA *
21     ***************************************************************************/
22    
23     #include "EGADSR.h"
24    
25     namespace LinuxSampler { namespace gig {
26    
27     EGADSR::EGADSR(gig::Engine* pEngine, Event::destination_t ModulationDestination) {
28     this->pEngine = pEngine;
29     this->ModulationDestination = ModulationDestination;
30     Stage = stage_end;
31     Level = 0.0;
32     }
33    
34     /**
35     * Will be called by the voice for every audio fragment to let the EG
36     * queue it's modulation changes for the current audio fragment.
37     *
38     * @param Samples - total number of sample points to be rendered in this
39     * audio fragment cycle by the audio engine
40     * @param pEvents - event list with "release" and "cancel release" events
41     * @param pTriggerEvent - event that caused triggering of the voice (only if
42     * the voices was triggered in the current audio
43     * fragment, NULL otherwise)
44     * @param SamplePos - current playback position
45     * @param CurrentPitch - current pitch value for playback
46     */
47     void EGADSR::Process(uint Samples, RTEList<Event>* pEvents, Event* pTriggerEvent, double SamplePos, double CurrentPitch) {
48     Event* pTransitionEvent;
49     if (pTriggerEvent) {
50     pEvents->set_current(pTriggerEvent);
51     pTransitionEvent = pEvents->next();
52     }
53     else {
54     pTransitionEvent = pEvents->first();
55     }
56    
57     int iSample = TriggerDelay;
58     while (iSample < Samples) {
59     switch (Stage) {
60     case stage_attack: {
61     TriggerDelay = 0;
62     int to_process = RTMath::Min(AttackStepsLeft, Samples - iSample);
63     int process_end = iSample + to_process;
64     AttackStepsLeft -= to_process;
65     while (iSample < process_end) {
66     Level += AttackCoeff;
67     pEngine->pSynthesisParameters[ModulationDestination][iSample++] *= Level;
68     }
69     if (iSample == Samples) { // postpone last transition event for the next audio fragment
70     Event* pLastEvent = pEvents->last();
71     if (pLastEvent) ReleasePostponed = (pLastEvent->Type == Event::type_release);
72     }
73     if (!AttackStepsLeft) Stage = (ReleasePostponed) ? stage_release : (HoldAttack) ? stage_attack_hold : stage_decay1;
74     break;
75     }
76     case stage_attack_hold: {
77     if (SamplePos >= LoopStart) {
78     Stage = stage_decay1;
79     break;
80     }
81     int holdstepsleft = (int) (LoopStart - SamplePos / CurrentPitch); // FIXME: just an approximation, inaccuracy grows with higher audio fragment size, sufficient for usual fragment sizes though
82     int to_process = RTMath::Min(holdstepsleft, Samples - iSample);
83     int process_end = iSample + to_process;
84     if (pTransitionEvent && pTransitionEvent->FragmentPos() <= process_end) {
85     process_end = pTransitionEvent->FragmentPos();
86     Stage = (pTransitionEvent->Type == Event::type_release) ? stage_release : (InfiniteSustain) ? stage_sustain : stage_decay2;
87     pTransitionEvent = pEvents->next();
88     }
89     else if (to_process == holdstepsleft) Stage = stage_decay1;
90     while (iSample < process_end) {
91     pEngine->pSynthesisParameters[ModulationDestination][iSample++] *= Level;
92     }
93     break;
94     }
95     case stage_decay1: {
96     int to_process = RTMath::Min(Samples - iSample, Decay1StepsLeft);
97     int process_end = iSample + to_process;
98     if (pTransitionEvent && pTransitionEvent->FragmentPos() <= process_end) {
99     process_end = pTransitionEvent->FragmentPos();
100     Stage = (pTransitionEvent->Type == Event::type_release) ? stage_release : (InfiniteSustain) ? stage_sustain : stage_decay2;
101     pTransitionEvent = pEvents->next();
102     }
103     else {
104     Decay1StepsLeft -= to_process;
105     if (!Decay1StepsLeft) Stage = (InfiniteSustain) ? stage_sustain : stage_decay2;
106     }
107     while (iSample < process_end) {
108     Level += Level * Decay1Coeff;
109     pEngine->pSynthesisParameters[ModulationDestination][iSample++] *= Level;
110     }
111     break;
112     }
113     case stage_decay2: {
114     int process_end;
115     if (pTransitionEvent && pTransitionEvent->Type == Event::type_release) {
116     process_end = pTransitionEvent->FragmentPos();
117     pTransitionEvent = pEvents->next();
118     Stage = stage_release; // switch to release stage soon
119     }
120     else process_end = Samples;
121     while (iSample < process_end) {
122     Level += Level * Decay2Coeff;
123     pEngine->pSynthesisParameters[ModulationDestination][iSample++] *= Level;
124     }
125     if (Level <= EG_ENVELOPE_LIMIT) Stage = stage_end;
126     break;
127     }
128     case stage_sustain: {
129     int process_end;
130     if (pTransitionEvent && pTransitionEvent->Type == Event::type_release) {
131     process_end = pTransitionEvent->FragmentPos();
132     pTransitionEvent = pEvents->next();
133     Stage = stage_release; // switch to release stage soon
134     }
135     else process_end = Samples;
136     while (iSample < process_end) {
137     pEngine->pSynthesisParameters[ModulationDestination][iSample++] *= Level;
138     }
139     break;
140     }
141     case stage_release: {
142     int process_end;
143     if (pTransitionEvent && pTransitionEvent->Type == Event::type_cancel_release) {
144     process_end = pTransitionEvent->FragmentPos();
145     pTransitionEvent = pEvents->next();
146     Stage = (InfiniteSustain) ? stage_sustain : stage_decay2; // switch back to sustain / decay2 stage soon
147     }
148     else process_end = Samples;
149     while (iSample < process_end) {
150     Level += Level * ReleaseCoeff;
151     pEngine->pSynthesisParameters[ModulationDestination][iSample++] *= Level;
152     }
153     if (Level <= EG_ENVELOPE_LIMIT) Stage = stage_end;
154     break;
155     }
156     case stage_end: {
157     while (iSample < Samples) {
158     Level += Level * ReleaseCoeff;
159     pEngine->pSynthesisParameters[ModulationDestination][iSample++] *= Level;
160     }
161     break;
162     }
163     }
164     }
165     }
166    
167     /**
168     * Will be called by the voice when the key / voice was triggered.
169     *
170     * @param PreAttack - Preattack value for the envelope (0 - 1000 permille)
171     * @param AttackTime - Attack time for the envelope (0.000 - 60.000s)
172     * @param HoldAttack - If true, Decay1 will be postponed until the sample reached the sample loop start.
173     * @param LoopStart - Sample position where sample loop starts (if any)
174     * @param Decay1Time - Decay1 time of the sample amplitude EG (0.000 - 60.000s).
175     * @param Decay2Time - Only if !InfiniteSustain: 2nd decay stage time of the sample amplitude EG (0.000 - 60.000s).
176     * @param InfiniteSustain - If true, instead of going into Decay2 phase, Decay1 level will be hold until note will be released.
177     * @param SustainLevel - Sustain level of the sample amplitude EG (0 - 1000 permille).
178     * @param ReleaseTIme - Release time for the envelope (0.000 - 60.000s)
179     * @param Delay - Number of sample points triggering should be delayed.
180     */
181     void EGADSR::Trigger(uint PreAttack, double AttackTime, bool HoldAttack, long LoopStart, double Decay1Time, double Decay2Time, bool InfiniteSustain, uint SustainLevel, double ReleaseTime, uint Delay) {
182     this->TriggerDelay = Delay;
183     this->Stage = stage_attack;
184     this->SustainLevel = (SustainLevel) ? (SustainLevel > EG_ENVELOPE_LIMIT) ? (float) SustainLevel / 1000.0 : EG_ENVELOPE_LIMIT : 1.0;
185     this->InfiniteSustain = InfiniteSustain;
186     this->HoldAttack = HoldAttack;
187     this->LoopStart = LoopStart;
188     this->ReleasePostponed = false;
189    
190     // calculate attack stage parameters (lin. curve)
191     AttackStepsLeft = (long) (AttackTime * pEngine->pAudioOutputDevice->SampleRate());
192     if (AttackStepsLeft) {
193     Level = (float) PreAttack / 1000.0;
194     AttackCoeff = (1.0 - Level) / AttackStepsLeft;
195     }
196     else {
197     Level = 1.0;
198     AttackCoeff = 0.0;
199     }
200    
201     // calculate decay1 stage parameters (exp. curve)
202     Decay1StepsLeft = (long) (Decay1Time * pEngine->pAudioOutputDevice->SampleRate());
203     Decay1Coeff = (Decay1StepsLeft) ? exp(log(this->SustainLevel) / (double) Decay1StepsLeft) - 1.0
204     : 0.0;
205    
206     // calculate decay2 stage parameters (exp. curve)
207     if (!InfiniteSustain) {
208     if (Decay2Time < EG_MIN_RELEASE_TIME) Decay2Time = EG_MIN_RELEASE_TIME;
209     long Decay2Steps = (long) (Decay2Time * pEngine->pAudioOutputDevice->SampleRate());
210     Decay2Coeff = (Decay2Steps) ? exp((log(EG_ENVELOPE_LIMIT) - log(this->SustainLevel)) / Decay2Steps + log(this->SustainLevel)) - this->SustainLevel
211     : 0.0;
212     }
213    
214     // calcuate release stage parameters (exp. curve)
215     if (ReleaseTime < EG_MIN_RELEASE_TIME) ReleaseTime = EG_MIN_RELEASE_TIME; // to avoid click sounds at the end of the sample playback
216     ReleaseStepsLeft = (long) (ReleaseTime * pEngine->pAudioOutputDevice->SampleRate());
217     ReleaseCoeff = exp((log(EG_ENVELOPE_LIMIT) - log(this->SustainLevel)) / ReleaseStepsLeft + log(this->SustainLevel)) - this->SustainLevel;
218    
219     dmsg(4,("PreAttack=%d, AttackLength=%d, AttackCoeff=%f, Decay1Coeff=%f, Decay2Coeff=%f, ReleaseLength=%d, ReleaseCoeff=%f\n",
220     PreAttack, AttackStepsLeft, AttackCoeff, Decay1Coeff, Decay2Coeff, ReleaseStepsLeft, ReleaseCoeff));
221     }
222    
223     }} // namespace LinuxSampler::gig

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