/***************************************************************************
* *
* Copyright (C) 2005 Christian Schoenebeck *
* Copyright (C) 2011 Christian Schoenebeck and Grigor Iliev *
* *
* This library 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 library 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 library; if not, write to the Free Software *
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
* MA 02111-1307 USA *
***************************************************************************/
#ifndef __LS_PULSELFO_H__
#define __LS_PULSELFO_H__
#include "LFOBase.h"
namespace LinuxSampler {
/** @brief Pulse LFO (int math implementation)
*
* This is a pulse Low Frequency Oscillator which uses pure integer
* math (without branches) to synthesize the pulse wave.
*/
template
class PulseLFO : public LFOBase {
public:
/**
* Constructor
*
* @param Max - maximum value of the output levels
*/
PulseLFO(float Max) : LFOBase::LFOBase(Max) {
}
/**
* Calculates exactly one sample point of the LFO wave.
*
* @returns next LFO level
*/
inline float render() {
uiLevel += c;
if (RANGE == LFO::range_unsigned)
return uiLevel <= width ? normalizer : 0;
else /* signed range */
return uiLevel <= width ? normalizer : -normalizer;
}
/**
* Update LFO depth with a new external controller value.
*
* @param ExtControlValue - new external controller value
*/
inline void updateByMIDICtrlValue(const uint16_t& ExtControlValue) {
this->ExtControlValue = ExtControlValue;
const float max = (this->InternalDepth + ExtControlValue * this->ExtControlDepthCoeff) * this->ScriptDepthFactor;
normalizer = max;
}
/**
* Will be called by the voice when the key / voice was triggered.
*
* @param Frequency - frequency of the oscillator in Hz
* @param InternalDepth - firm, internal oscillator amplitude
* @param ExtControlDepth - defines how strong the external MIDI
* controller has influence on the
* oscillator amplitude
* @param FlipPhase - inverts the oscillator wave against
* a horizontal axis
* @param SampleRate - current sample rate of the engines
* audio output signal
* @param PulseWidth - the pulse width in percents
*/
void trigger(float Frequency, uint16_t InternalDepth, uint16_t ExtControlDepth, float PulseWidth, unsigned int SampleRate) {
this->Frequency = Frequency;
this->InternalDepth = (InternalDepth / 1200.0f) * this->Max;
this->ExtControlDepthCoeff = (((float) ExtControlDepth / 1200.0f) / 127.0f) * this->Max;
this->ScriptFrequencyFactor = this->ScriptDepthFactor = 1.f; // reset for new voice
this->pFinalDepth = NULL;
this->pFinalFrequency = NULL;
const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
const float freq = Frequency * this->ScriptFrequencyFactor;
const float r = freq / (float) SampleRate; // frequency alteration quotient
c = (int) (intLimit * r);
width = (PulseWidth / 100.0) * intLimit;
uiLevel = 0;
}
virtual void trigger(float Frequency, LFO::start_level_t StartLevel, uint16_t InternalDepth, uint16_t ExtControlDepth, bool FlipPhase, unsigned int SampleRate) {
trigger(Frequency, InternalDepth, ExtControlDepth, WIDTH / 10.0f, SampleRate);
}
/**
* Should be invoked after the LFO is triggered.
* @param phase From 0 to 360 degrees.
*/
void setPhase(float phase) {
if (phase < 0) phase = 0;
if (phase > 360) phase = 360;
phase /= 360.0f;
const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
uiLevel = intLimit * phase;
}
void setFrequency(float Frequency, unsigned int SampleRate) {
this->Frequency = Frequency;
const float freq = Frequency * this->ScriptFrequencyFactor;
const unsigned int intLimit = (unsigned int) -1; // all 0xFFFF...
float r = freq / (float) SampleRate; // frequency alteration quotient
c = (int) (intLimit * r);
}
void setScriptDepthFactor(float factor, bool isFinal) {
this->ScriptDepthFactor = factor;
// set or reset this script depth parameter to be the sole
// source for the LFO depth
if (isFinal && !this->pFinalDepth)
this->pFinalDepth = &this->ScriptDepthFactor;
else if (!isFinal && this->pFinalDepth == &this->ScriptDepthFactor)
this->pFinalDepth = NULL;
// recalculate upon new depth
updateByMIDICtrlValue(this->ExtControlValue);
}
void setScriptFrequencyFactor(float factor, unsigned int SampleRate) {
this->ScriptFrequencyFactor = factor;
// in case script frequency was set as "final" value before,
// reset it so that all sources are processed from now on
if (this->pFinalFrequency == &this->ScriptFrequencyFactor)
this->pFinalFrequency = NULL;
// recalculate upon new frequency
setFrequency(this->Frequency, SampleRate);
}
void setScriptFrequencyFinal(float hz, unsigned int SampleRate) {
this->ScriptFrequencyFactor = hz;
// assign script's given frequency as sole source for the LFO
// frequency, thus ignore all other sources
if (!this->pFinalFrequency)
this->pFinalFrequency = &this->ScriptFrequencyFactor;
// recalculate upon new frequency
setFrequency(this->Frequency, SampleRate);
}
protected:
unsigned int uiLevel;
unsigned int width;
int c;
float normalizer;
};
template
class SquareLFO : public PulseLFO {
public:
SquareLFO(float Max) : PulseLFO::PulseLFO(Max) { }
};
} // namespace LinuxSampler
#endif // __LS_PULSELFO_H__