/[svn]/linuxsampler/trunk/src/engines/common/LFOTriangleIntMath.h
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Annotation of /linuxsampler/trunk/src/engines/common/LFOTriangleIntMath.h

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Mon Sep 30 17:35:43 2019 UTC (14 months ago) by schoenebeck
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* LFOTriangleIntMath and LFOTriangleIntAbsMath: Fixed FlipPhase=true
  behaviour for start_level_mid.

* Bumped version (2.1.1.svn17).

1 schoenebeck 717 /***************************************************************************
2     * *
3 schoenebeck 3561 * Copyright (C) 2005 - 2019 Christian Schoenebeck *
4 schoenebeck 717 * *
5     * This library is free software; you can redistribute it and/or modify *
6     * it under the terms of the GNU General Public License as published by *
7     * the Free Software Foundation; either version 2 of the License, or *
8     * (at your option) any later version. *
9     * *
10     * This library is distributed in the hope that it will be useful, *
11     * but WITHOUT ANY WARRANTY; without even the implied warranty of *
12     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
13     * GNU General Public License for more details. *
14     * *
15     * You should have received a copy of the GNU General Public License *
16     * along with this library; if not, write to the Free Software *
17     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
18     * MA 02111-1307 USA *
19     ***************************************************************************/
20    
21     #ifndef __LS_LFOTRIANGLEINTMATH_H__
22     #define __LS_LFOTRIANGLEINTMATH_H__
23    
24     #include "LFOBase.h"
25    
26     namespace LinuxSampler {
27    
28     /** @brief Triangle LFO (int math implementation)
29     *
30     * This is a triangle Low Frequency Oscillator which uses pure integer
31     * math (without branches) to synthesize the triangular wave.
32     */
33     template<range_type_t RANGE>
34     class LFOTriangleIntMath : public LFOBase<RANGE> {
35     public:
36    
37     /**
38     * Constructor
39     *
40     * @param Max - maximum value of the output levels
41     */
42     LFOTriangleIntMath(float Max) : LFOBase<RANGE>::LFOBase(Max) {
43     }
44    
45     /**
46     * Calculates exactly one sample point of the LFO wave.
47     *
48     * @returns next LFO level
49     */
50     inline float render() {
51     const int signshifts = (sizeof(int) * 8) - 1;
52     iLevel += c;
53     const int iSign = (iLevel >> signshifts) | 1;
54     if (RANGE == range_unsigned)
55     return normalizer * (float) (iSign * iLevel);
56     else /* signed range */
57     return normalizer * (float) (iSign * iLevel) + offset;
58     }
59    
60     /**
61     * Update LFO depth with a new external controller value.
62     *
63     * @param ExtControlValue - new external controller value
64     */
65 schoenebeck 3118 inline void updateByMIDICtrlValue(const uint16_t& ExtControlValue) {
66     this->ExtControlValue = ExtControlValue;
67    
68 schoenebeck 717 const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
69 schoenebeck 3118 const float max = (this->InternalDepth + ExtControlValue * this->ExtControlDepthCoeff) * this->ScriptDepthFactor;
70 schoenebeck 717 if (RANGE == range_unsigned) {
71 schoenebeck 718 normalizer = max / (float) intLimit;
72 schoenebeck 717 } else { // signed range
73 schoenebeck 718 normalizer = max / (float) intLimit * 4.0f;
74 schoenebeck 717 offset = -max;
75     }
76     }
77    
78     /**
79     * Will be called by the voice when the key / voice was triggered.
80     *
81     * @param Frequency - frequency of the oscillator in Hz
82     * @param StartLevel - on which level the wave should start
83     * @param InternalDepth - firm, internal oscillator amplitude
84     * @param ExtControlDepth - defines how strong the external MIDI
85     * controller has influence on the
86     * oscillator amplitude
87 schoenebeck 718 * @param FlipPhase - inverts the oscillator wave against
88     * a horizontal axis
89 schoenebeck 717 * @param SampleRate - current sample rate of the engines
90     * audio output signal
91     */
92     void trigger(float Frequency, start_level_t StartLevel, uint16_t InternalDepth, uint16_t ExtControlDepth, bool FlipPhase, unsigned int SampleRate) {
93 schoenebeck 3118 this->Frequency = Frequency;
94 senkov 719 this->InternalDepth = (InternalDepth / 1200.0f) * this->Max;
95     this->ExtControlDepthCoeff = (((float) ExtControlDepth / 1200.0f) / 127.0f) * this->Max;
96 schoenebeck 3118 this->ScriptFrequencyFactor = this->ScriptDepthFactor = 1.f; // reset for new voice
97 schoenebeck 718 if (RANGE == range_unsigned) {
98     this->InternalDepth *= 2.0f;
99     this->ExtControlDepthCoeff *= 2.0f;
100     }
101 schoenebeck 3561 this->pFinalDepth = NULL;
102     this->pFinalFrequency = NULL;
103 schoenebeck 717
104     const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
105 schoenebeck 3118 const float freq = Frequency * this->ScriptFrequencyFactor;
106     const float r = freq / (float) SampleRate; // frequency alteration quotient
107 schoenebeck 717 c = (int) (intLimit * r);
108    
109     switch (StartLevel) {
110 schoenebeck 718 case start_level_max:
111     iLevel = (FlipPhase) ? 0 : intLimit >> 1;
112 schoenebeck 717 break;
113 schoenebeck 718 case start_level_mid:
114 schoenebeck 3611 iLevel = (FlipPhase) ? intLimit / 4 * 3 : intLimit >> 2;
115 schoenebeck 717 break;
116 schoenebeck 718 case start_level_min:
117     iLevel = (FlipPhase) ? intLimit >> 1 : 0;
118 schoenebeck 717 break;
119     }
120     }
121 iliev 2225
122     /**
123     * Should be invoked after the LFO is triggered.
124     * @param phase From 0 to 360 degrees.
125     */
126     void setPhase(float phase) {
127     if (phase < 0) phase = 0;
128     if (phase > 360) phase = 360;
129     phase /= 360.0f;
130     const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
131     unsigned int uiPhase = intLimit * phase + iLevel;
132     if (uiPhase > intLimit / 2) iLevel = uiPhase - intLimit;
133     else iLevel = uiPhase;
134     }
135 iliev 2227
136     void setFrequency(float Frequency, unsigned int SampleRate) {
137 schoenebeck 3118 this->Frequency = Frequency;
138     const float freq = Frequency * this->ScriptFrequencyFactor;
139 iliev 2227 const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
140 schoenebeck 3118 float r = freq / (float) SampleRate; // frequency alteration quotient
141 iliev 2227 c = (int) (intLimit * r);
142     }
143 schoenebeck 717
144 schoenebeck 3561 void setScriptDepthFactor(float factor, bool isFinal) {
145 schoenebeck 3118 this->ScriptDepthFactor = factor;
146 schoenebeck 3561 // set or reset this script depth parameter to be the sole
147     // source for the LFO depth
148     if (isFinal && !this->pFinalDepth)
149     this->pFinalDepth = &this->ScriptDepthFactor;
150     else if (!isFinal && this->pFinalDepth == &this->ScriptDepthFactor)
151     this->pFinalDepth = NULL;
152     // recalculate upon new depth
153 schoenebeck 3118 updateByMIDICtrlValue(this->ExtControlValue);
154     }
155    
156     void setScriptFrequencyFactor(float factor, unsigned int SampleRate) {
157     this->ScriptFrequencyFactor = factor;
158 schoenebeck 3561 // in case script frequency was set as "final" value before,
159     // reset it so that all sources are processed from now on
160     if (this->pFinalFrequency == &this->ScriptFrequencyFactor)
161     this->pFinalFrequency = NULL;
162     // recalculate upon new frequency
163 schoenebeck 3118 setFrequency(this->Frequency, SampleRate);
164     }
165    
166 schoenebeck 3561 void setScriptFrequencyFinal(float hz, unsigned int SampleRate) {
167     this->ScriptFrequencyFactor = hz;
168     // assign script's given frequency as sole source for the LFO
169     // frequency, thus ignore all other sources
170     if (!this->pFinalFrequency)
171     this->pFinalFrequency = &this->ScriptFrequencyFactor;
172     // recalculate upon new frequency
173     setFrequency(this->Frequency, SampleRate);
174     }
175    
176 senkov 720 protected:
177 schoenebeck 717 int iLevel;
178     int c;
179     float offset; ///< only needed for signed range
180     float normalizer;
181     };
182    
183     } // namespace LinuxSampler
184    
185     #endif // __LS_LFOTRIANGLEINTMATH_H__

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