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

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Revision 796 - (hide annotations) (download) (as text)
Sun Oct 30 08:35:13 2005 UTC (15 years, 3 months ago) by persson
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File size: 8402 byte(s)
* fixed voice stealing - stolen voices weren't killed

1 schoenebeck 53 /***************************************************************************
2     * *
3     * LinuxSampler - modular, streaming capable sampler *
4     * *
5 schoenebeck 56 * Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6 schoenebeck 554 * Copyright (C) 2005 Christian Schoenebeck *
7 schoenebeck 53 * *
8     * This program is free software; you can redistribute it and/or modify *
9     * it under the terms of the GNU General Public License as published by *
10     * the Free Software Foundation; either version 2 of the License, or *
11     * (at your option) any later version. *
12     * *
13     * This program is distributed in the hope that it will be useful, *
14     * but WITHOUT ANY WARRANTY; without even the implied warranty of *
15     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
16     * GNU General Public License for more details. *
17     * *
18     * You should have received a copy of the GNU General Public License *
19     * along with this program; if not, write to the Free Software *
20     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
21     * MA 02111-1307 USA *
22     ***************************************************************************/
23    
24     #ifndef __LS_GIG_EGADSR_H__
25     #define __LS_GIG_EGADSR_H__
26    
27     #include "../../common/global.h"
28     #include "../../common/RTMath.h"
29    
30     namespace LinuxSampler { namespace gig {
31    
32     /**
33     * ADSR Envelope Generator
34     *
35     * Envelope Generator with stage 'Attack', 'Attack_Hold', 'Decay_1',
36     * 'Decay_2', 'Sustain' and 'Release' for modulating arbitrary synthesis
37     * parameters.
38     */
39     class EGADSR {
40     public:
41 schoenebeck 738
42     /**
43     * Used to define what kind of segment the envelope currently is at.
44     */
45     enum segment_t {
46     segment_end = 0, ///< final end state of envelope reached
47     segment_lin = 1, ///< envelope is currently at a linear segment
48     segment_exp = 2 ///< envelope is currently at a exponental segment
49     };
50    
51     /**
52     * Used to inform the EG about an event.
53     */
54     enum event_t {
55     event_stage_end,
56     event_release,
57 persson 783 event_cancel_release,
58     event_hold_end
59 schoenebeck 738 };
60    
61     /**
62     * Constructor
63     */
64     EGADSR();
65    
66     /**
67     * Change fade out time.
68     */
69     void CalculateFadeOutCoeff(float FadeOutTime, float SampleRate);
70    
71     /**
72     * Will be called by the voice when the key / voice was triggered.
73     *
74     * @param PreAttack - Preattack value for the envelope
75     * (0 - 1000 permille)
76     * @param AttackTime - Attack time for the envelope
77     * (0.000 - 60.000s)
78     * @param HoldAttack - if true, Decay1 will be postponed until the
79     * sample reached the sample loop start.
80     * @param Decay1Time - Decay1 time of the sample amplitude EG
81     * (0.000 - 60.000s)
82     * @param Decay2Time - only if !InfiniteSustain: 2nd decay stage
83     * time of the sample amplitude EG
84     * (0.000 - 60.000s)
85     * @param InfiniteSustain - if true, instead of going into Decay2
86     * stage, Decay1 level will be hold until note
87     * will be released
88     * @param SustainLevel - Sustain level of the sample amplitude EG
89     * (0 - 1000 permille)
90     * @param ReleaseTIme - Release time for the envelope
91     * (0.000 - 60.000s)
92     * @param Volume - volume the sample will be played at
93     * (0.0 - 1.0) - used when calculating the
94     * exponential curve parameters.
95     * @param SampleRate - sample rate of used audio output driver
96     */
97 persson 783 void trigger(uint PreAttack, float AttackTime, bool HoldAttack, float Decay1Time, double Decay2Time, bool InfiniteSustain, uint SustainLevel, float ReleaseTime, float Volume, uint SampleRate); //FIXME: we should better use 'float' for SampleRate
98 schoenebeck 738
99     /**
100     * Returns true in case envelope hasn't reached its final end state yet.
101     */
102     inline bool active() {
103     return (bool) Segment;
104     }
105    
106     /**
107     * Returns what kind of segment the envelope currently is at.
108     */
109     inline segment_t getSegmentType() {
110     return Segment;
111     }
112    
113     /**
114     * Advance envelope by \a SamplePoints steps.
115     */
116     inline void increment(int SamplePoints) {
117     StepsLeft = RTMath::Max(0, StepsLeft - SamplePoints);
118     }
119    
120     /**
121     * Returns amount of steps until the end of current envelope stage.
122     */
123     inline int toStageEndLeft() {
124     return StepsLeft;
125     }
126    
127     /**
128     * Should be called to inform the EG about an external event and
129     * also whenever an envelope stage is completed. This will handle
130     * the envelope's transition to the respective next stage.
131     *
132     * @param Event - what happened
133     */
134 persson 783 void update(event_t Event, uint SampleRate);
135 schoenebeck 738
136     /**
137     * Calculates exactly one, the next sample point of EG
138     * (linear segment). Call this if envelope is currently in a linear
139     * segment.
140     *
141     * @returns next envelope level
142     */
143     inline float processLin() {
144     return (Level += Coeff);
145     }
146    
147     /**
148     * Calculates exactly one, the next sample point of EG
149     * (exponential segment). Call this if envelope is currently in an
150     * exponential segment.
151     *
152     * @returns next envelope level
153     */
154     inline float processExp() {
155     return (Level = Level * Coeff + Offset);
156     }
157    
158     /**
159     * Returns current envelope level without modifying anything. This
160     * might be needed once the envelope reached its final end state,
161     * because calling processLin() or processExp() at this point will
162     * result in undesired behavior.
163     */
164     inline float getLevel() {
165     return Level;
166     }
167    
168 persson 796 void enterFadeOutStage();
169    
170 schoenebeck 738 private:
171    
172 schoenebeck 53 enum stage_t {
173     stage_attack,
174     stage_attack_hold,
175 schoenebeck 738 stage_decay1_part1,
176 persson 614 stage_decay1_part2,
177 schoenebeck 53 stage_decay2,
178     stage_sustain,
179 schoenebeck 738 stage_release_part1,
180 persson 614 stage_release_part2,
181 schoenebeck 252 stage_fadeout,
182 schoenebeck 53 stage_end
183     };
184    
185 schoenebeck 738 float Level;
186     float Coeff;
187     float Offset;
188     int StepsLeft;
189     segment_t Segment;
190     stage_t Stage;
191     bool HoldAttack;
192     bool InfiniteSustain;
193     float Decay1Time;
194     float Decay1Level2;
195     float Decay1Slope;
196     float Decay2Time;
197     float SustainLevel;
198     float ReleaseCoeff;
199     float ReleaseCoeff2;
200     float ReleaseCoeff3;
201     float ReleaseLevel2;
202     float ReleaseSlope;
203     float invVolume;
204     float ExpOffset;
205     float FadeOutCoeff; ///< very fast ramp down for e.g. voice stealing
206    
207 persson 783 void enterAttackStage(const uint PreAttack, const float AttackTime, const uint SampleRate);
208     void enterAttackHoldStage();
209 schoenebeck 738 void enterDecay1Part1Stage(const uint SampleRate);
210 persson 768 void enterDecay1Part2Stage(const uint SampleRate);
211 schoenebeck 738 void enterDecay2Stage(const uint SampleRate);
212     void enterSustainStage();
213     void enterReleasePart1Stage();
214     void enterReleasePart2Stage();
215     void enterEndStage();
216 schoenebeck 53 };
217    
218     }} // namespace LinuxSampler::gig
219    
220     #endif // __LS_GIG_EGADSR_H__

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