engines/gig/EGADSR.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 Christian Schoenebeck                              *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 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 General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#ifndef __LS_GIG_EGADSR_H__
#define __LS_GIG_EGADSR_H__

#include "../../common/global.h"
#include "../../common/RTMath.h"

namespace LinuxSampler { namespace gig {

/**
 * ADSR Envelope Generator
 *
 * Envelope Generator with stage 'Attack', 'Attack_Hold', 'Decay_1',
 * 'Decay_2', 'Sustain' and 'Release' for modulating arbitrary synthesis
 * parameters.
 */
class EGADSR {
    public:

        /**
         * Used to define what kind of segment the envelope currently is at.
         */
        enum segment_t {
            segment_end = 0, ///< final end state of envelope reached
            segment_lin = 1, ///< envelope is currently at a linear segment
            segment_exp = 2  ///< envelope is currently at a exponental segment
        };

        /**
         * Used to inform the EG about an event.
         */
        enum event_t {
            event_stage_end,
            event_release,
            event_cancel_release
        };

        /**
         * Constructor
         */
        EGADSR();

        /**
         * Change fade out time.
         */
        void CalculateFadeOutCoeff(float FadeOutTime, float SampleRate);

        /**
         * Will be called by the voice when the key / voice was triggered.
         *
         * @param PreAttack       - Preattack value for the envelope
         *                          (0 - 1000 permille)
         * @param AttackTime      - Attack time for the envelope
         *                          (0.000 - 60.000s)
         * @param HoldAttack      - if true, Decay1 will be postponed until the
         *                          sample reached the sample loop start.
         * @param LoopStart       - sample position where sample loop starts
         *                          (if any)
         * @param Decay1Time      - Decay1 time of the sample amplitude EG
         *                          (0.000 - 60.000s)
         * @param Decay2Time      - only if !InfiniteSustain: 2nd decay stage
         *                          time of the sample amplitude EG
         *                          (0.000 - 60.000s)
         * @param InfiniteSustain - if true, instead of going into Decay2
         *                          stage, Decay1 level will be hold until note
         *                          will be released
         * @param SustainLevel    - Sustain level of the sample amplitude EG
         *                          (0 - 1000 permille)
         * @param ReleaseTIme     - Release time for the envelope
         *                          (0.000 - 60.000s)
         * @param Volume          - volume the sample will be played at
         *                          (0.0 - 1.0) - used when calculating the
         *                          exponential curve parameters.
         * @param SampleRate      - sample rate of used audio output driver
         */
        void trigger(uint PreAttack, float AttackTime, bool HoldAttack, long LoopStart, float Decay1Time, double Decay2Time, bool InfiniteSustain, uint SustainLevel, float ReleaseTime, float Volume, uint SampleRate); //FIXME: we should better use 'float' for SampleRate

        /**
         * Returns true in case envelope hasn't reached its final end state yet.
         */
        inline bool active() {
            return (bool) Segment;
        }

        /**
         * Returns what kind of segment the envelope currently is at.
         */
        inline segment_t getSegmentType() {
            return Segment;
        }

        /**
         * Advance envelope by \a SamplePoints steps.
         */
        inline void increment(int SamplePoints) {
            StepsLeft = RTMath::Max(0, StepsLeft - SamplePoints);
        }

        /**
         * Returns amount of steps until the end of current envelope stage.
         */
        inline int toStageEndLeft() {
            return StepsLeft;
        }

        /**
         * Should be called to inform the EG about an external event and
         * also whenever an envelope stage is completed. This will handle
         * the envelope's transition to the respective next stage.
         *
         * @param Event        - what happened
         * @param SamplePos    - current sample playback position
         * @param CurrentPitch - current frequency alternation quotient
         */
        void update(event_t Event, double SamplePos, float CurrentPitch, uint SampleRate);

        /**
         * Calculates exactly one, the next sample point of EG
         * (linear segment). Call this if envelope is currently in a linear
         * segment.
         *
         * @returns next envelope level
         */
        inline float processLin() {
            return (Level += Coeff);
        }

        /**
         * Calculates exactly one, the next sample point of EG
         * (exponential segment). Call this if envelope is currently in an
         * exponential segment.
         *
         * @returns next envelope level
         */
        inline float processExp() {
            return (Level = Level * Coeff + Offset);
        }

        /**
         * Returns current envelope level without modifying anything. This
         * might be needed once the envelope reached its final end state,
         * because calling processLin() or processExp() at this point will
         * result in undesired behavior.
         */
        inline float getLevel() {
            return Level;
        }

    private:

        enum stage_t {
            stage_attack,
            stage_attack_hold,
            stage_decay1_part1,
            stage_decay1_part2,
            stage_decay2,
            stage_sustain,
            stage_release_part1,
            stage_release_part2,
            stage_fadeout,
            stage_end
        };

        float     Level;
        float     Coeff;
        float     Offset;
        int       StepsLeft;
        segment_t Segment;
        stage_t   Stage;
        event_t   PostponedEvent; ///< only used in Attack stage to postpone transition events until attack time is reached
        bool      HoldAttack;
        bool      InfiniteSustain;
        long      LoopStart;
        float     Decay1Time;
        float     Decay1Level2;
        float     Decay1Slope;
        float     Decay2Time;
        float     SustainLevel;
        float     ReleaseCoeff;
        float     ReleaseCoeff2;
        float     ReleaseCoeff3;
        float     ReleaseLevel2;
        float     ReleaseSlope;
        float     invVolume;
        float     ExpOffset;
        float     FadeOutCoeff; ///< very fast ramp down for e.g. voice stealing

        void enterAttackStage(const uint PreAttack, const float AttackTime, const uint SampleRate, const double SamplePos, const float CurrentPitch);
        void enterAttackHoldStage(const double SamplePos, const float CurrentPitch);
        void enterDecay1Part1Stage(const uint SampleRate);
        void enterDecay1Part2Stage();
        void enterDecay2Stage(const uint SampleRate);
        void enterSustainStage();
        void enterReleasePart1Stage();
        void enterReleasePart2Stage();
        void enterFadeOutStage();
        void enterEndStage();
};

}} // namespace LinuxSampler::gig

#endif // __LS_GIG_EGADSR_H__
1	/***************************************************************************
2	* *
3	* LinuxSampler - modular, streaming capable sampler *
4	* *
5	* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6	* Copyright (C) 2005 Christian Schoenebeck *
7	* *
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
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	event_cancel_release
58	};
59
60	/**
61	* Constructor
62	*/
63	EGADSR();
64
65	/**
66	* Change fade out time.
67	*/
68	void CalculateFadeOutCoeff(float FadeOutTime, float SampleRate);
69
70	/**
71	* Will be called by the voice when the key / voice was triggered.
72	*
73	* @param PreAttack - Preattack value for the envelope
74	* (0 - 1000 permille)
75	* @param AttackTime - Attack time for the envelope
76	* (0.000 - 60.000s)
77	* @param HoldAttack - if true, Decay1 will be postponed until the
78	* sample reached the sample loop start.
79	* @param LoopStart - sample position where sample loop starts
80	* (if any)
81	* @param Decay1Time - Decay1 time of the sample amplitude EG
82	* (0.000 - 60.000s)
83	* @param Decay2Time - only if !InfiniteSustain: 2nd decay stage
84	* time of the sample amplitude EG
85	* (0.000 - 60.000s)
86	* @param InfiniteSustain - if true, instead of going into Decay2
87	* stage, Decay1 level will be hold until note
88	* will be released
89	* @param SustainLevel - Sustain level of the sample amplitude EG
90	* (0 - 1000 permille)
91	* @param ReleaseTIme - Release time for the envelope
92	* (0.000 - 60.000s)
93	* @param Volume - volume the sample will be played at
94	* (0.0 - 1.0) - used when calculating the
95	* exponential curve parameters.
96	* @param SampleRate - sample rate of used audio output driver
97	*/
98	void trigger(uint PreAttack, float AttackTime, bool HoldAttack, long LoopStart, float Decay1Time, double Decay2Time, bool InfiniteSustain, uint SustainLevel, float ReleaseTime, float Volume, uint SampleRate); //FIXME: we should better use 'float' for SampleRate
99
100	/**
101	* Returns true in case envelope hasn't reached its final end state yet.
102	*/
103	inline bool active() {
104	return (bool) Segment;
105	}
106
107	/**
108	* Returns what kind of segment the envelope currently is at.
109	*/
110	inline segment_t getSegmentType() {
111	return Segment;
112	}
113
114	/**
115	* Advance envelope by \a SamplePoints steps.
116	*/
117	inline void increment(int SamplePoints) {
118	StepsLeft = RTMath::Max(0, StepsLeft - SamplePoints);
119	}
120
121	/**
122	* Returns amount of steps until the end of current envelope stage.
123	*/
124	inline int toStageEndLeft() {
125	return StepsLeft;
126	}
127
128	/**
129	* Should be called to inform the EG about an external event and
130	* also whenever an envelope stage is completed. This will handle
131	* the envelope's transition to the respective next stage.
132	*
133	* @param Event - what happened
134	* @param SamplePos - current sample playback position
135	* @param CurrentPitch - current frequency alternation quotient
136	*/
137	void update(event_t Event, double SamplePos, float CurrentPitch, uint SampleRate);
138
139	/**
140	* Calculates exactly one, the next sample point of EG
141	* (linear segment). Call this if envelope is currently in a linear
142	* segment.
143	*
144	* @returns next envelope level
145	*/
146	inline float processLin() {
147	return (Level += Coeff);
148	}
149
150	/**
151	* Calculates exactly one, the next sample point of EG
152	* (exponential segment). Call this if envelope is currently in an
153	* exponential segment.
154	*
155	* @returns next envelope level
156	*/
157	inline float processExp() {
158	return (Level = Level * Coeff + Offset);
159	}
160
161	/**
162	* Returns current envelope level without modifying anything. This
163	* might be needed once the envelope reached its final end state,
164	* because calling processLin() or processExp() at this point will
165	* result in undesired behavior.
166	*/
167	inline float getLevel() {
168	return Level;
169	}
170
171	private:
172
173	enum stage_t {
174	stage_attack,
175	stage_attack_hold,
176	stage_decay1_part1,
177	stage_decay1_part2,
178	stage_decay2,
179	stage_sustain,
180	stage_release_part1,
181	stage_release_part2,
182	stage_fadeout,
183	stage_end
184	};
185
186	float Level;
187	float Coeff;
188	float Offset;
189	int StepsLeft;
190	segment_t Segment;
191	stage_t Stage;
192	event_t PostponedEvent; ///< only used in Attack stage to postpone transition events until attack time is reached
193	bool HoldAttack;
194	bool InfiniteSustain;
195	long LoopStart;
196	float Decay1Time;
197	float Decay1Level2;
198	float Decay1Slope;
199	float Decay2Time;
200	float SustainLevel;
201	float ReleaseCoeff;
202	float ReleaseCoeff2;
203	float ReleaseCoeff3;
204	float ReleaseLevel2;
205	float ReleaseSlope;
206	float invVolume;
207	float ExpOffset;
208	float FadeOutCoeff; ///< very fast ramp down for e.g. voice stealing
209
210	void enterAttackStage(const uint PreAttack, const float AttackTime, const uint SampleRate, const double SamplePos, const float CurrentPitch);
211	void enterAttackHoldStage(const double SamplePos, const float CurrentPitch);
212	void enterDecay1Part1Stage(const uint SampleRate);
213	void enterDecay1Part2Stage();
214	void enterDecay2Stage(const uint SampleRate);
215	void enterSustainStage();
216	void enterReleasePart1Stage();
217	void enterReleasePart2Stage();
218	void enterFadeOutStage();
219	void enterEndStage();
220	};
221
222	}} // namespace LinuxSampler::gig
223
224	#endif // __LS_GIG_EGADSR_H__