/[svn]/linuxsampler/trunk/src/engines/common/SawLFO.h
ViewVC logotype

Contents of /linuxsampler/trunk/src/engines/common/SawLFO.h

Parent Directory Parent Directory | Revision Log Revision Log


Revision 2225 - (show annotations) (download) (as text)
Tue Aug 2 13:44:57 2011 UTC (12 years, 7 months ago) by iliev
File MIME type: text/x-c++hdr
File size: 5905 byte(s)
* sfz engine: implemented opcodes lfoN_phase, lfoN_phase_onccX,
  lfoN_pitch, lfoN_pitch_onccX

1 /***************************************************************************
2 * *
3 * Copyright (C) 2005 Christian Schoenebeck *
4 * Copyright (C) 2011 Christian Schoenebeck and Grigor Iliev *
5 * *
6 * This library is free software; you can redistribute it and/or modify *
7 * it under the terms of the GNU General Public License as published by *
8 * the Free Software Foundation; either version 2 of the License, or *
9 * (at your option) any later version. *
10 * *
11 * This library is distributed in the hope that it will be useful, *
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
14 * GNU General Public License for more details. *
15 * *
16 * You should have received a copy of the GNU General Public License *
17 * along with this library; if not, write to the Free Software *
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
19 * MA 02111-1307 USA *
20 ***************************************************************************/
21
22 #ifndef __LS_SAWLFO_H__
23 #define __LS_SAWLFO_H__
24
25 #include "LFOBase.h"
26
27 namespace LinuxSampler {
28
29 /** @brief Saw LFO (int math implementation)
30 *
31 * This is a saw Low Frequency Oscillator which uses pure integer
32 * math (without branches) to synthesize the saw wave.
33 */
34 template<range_type_t RANGE, bool SAWUP>
35 class SawLFO : public LFOBase<RANGE> {
36 public:
37
38 /**
39 * Constructor
40 *
41 * @param Max - maximum value of the output levels
42 */
43 SawLFO(float Max) : LFOBase<RANGE>::LFOBase(Max) {
44 }
45
46 /**
47 * Calculates exactly one sample point of the LFO wave.
48 *
49 * @returns next LFO level
50 */
51 inline float render() {
52 const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
53
54 uiLevel += c;
55 if (RANGE == range_unsigned)
56 return normalizer * (float) (SAWUP ? uiLevel : intLimit - uiLevel);
57 else /* signed range */
58 return normalizer * (float) (SAWUP ? uiLevel : intLimit - uiLevel) + offset;
59 }
60
61 /**
62 * Update LFO depth with a new external controller value.
63 *
64 * @param ExtControlValue - new external controller value
65 */
66 inline void update(const uint16_t& ExtControlValue) {
67 const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
68 const float max = this->InternalDepth + ExtControlValue * this->ExtControlDepthCoeff;
69 if (RANGE == range_unsigned) {
70 normalizer = max / (float) intLimit;
71 } else { // signed range
72 normalizer = max / (float) intLimit * 2.0f;
73 offset = -max;
74 }
75 }
76
77 /**
78 * Will be called by the voice when the key / voice was triggered.
79 *
80 * @param Frequency - frequency of the oscillator in Hz
81 * @param StartLevel - not implemented
82 * @param InternalDepth - firm, internal oscillator amplitude
83 * @param ExtControlDepth - defines how strong the external MIDI
84 * controller has influence on the
85 * oscillator amplitude
86 * @param FlipPhase - not implemented
87 * @param SampleRate - current sample rate of the engines
88 * audio output signal
89 */
90 virtual void trigger(float Frequency, start_level_t StartLevel, uint16_t InternalDepth, uint16_t ExtControlDepth, bool FlipPhase, unsigned int SampleRate) {
91 this->InternalDepth = (InternalDepth / 1200.0f) * this->Max;
92 this->ExtControlDepthCoeff = (((float) ExtControlDepth / 1200.0f) / 127.0f) * this->Max;
93
94 const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
95 const float r = Frequency / (float) SampleRate; // frequency alteration quotient
96 c = (int) (intLimit * r);
97
98 uiLevel = 0;
99 }
100
101 /**
102 * Should be invoked after the LFO is triggered.
103 * @param phase From 0 to 360 degrees.
104 */
105 void setPhase(float phase) {
106 if (phase < 0) phase = 0;
107 if (phase > 360) phase = 360;
108 phase /= 360.0f;
109 const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
110 uiLevel = intLimit * phase;
111 }
112
113 protected:
114 unsigned int uiLevel;
115 int c;
116 float offset; ///< only needed for signed range
117 float normalizer;
118 };
119
120
121 template<range_type_t RANGE>
122 class SawUpLFO : public SawLFO<RANGE, true> {
123 public:
124 SawUpLFO(float Max) : SawLFO<RANGE, true>::SawLFO(Max) { }
125 };
126
127 template<range_type_t RANGE>
128 class SawDownLFO : public SawLFO<RANGE, false> {
129 public:
130 SawDownLFO(float Max) : SawLFO<RANGE, false>::SawLFO(Max) { }
131 };
132
133 } // namespace LinuxSampler
134
135 #endif // __LS_SAWLFO_H__

  ViewVC Help
Powered by ViewVC