MOLOSS Code

/**************************************************************************
   Copyright (C) 2019 Arnaud Champenois arthelion@free.fr

	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 3 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, see <http://www.gnu.org/licenses/>.
**************************************************************************/

#pragma once
#include "WaveGenerator.h"
#include "Utils.h"

/*!
 * The LFO outputs a varying triangular signal between -1 and 1, with a delay
 * The oscillation begins with a small ramp before the delay.
 * 
 */
class LFO {
public:
	LFO() {}
	~LFO() {}

	void init(double sampligfreq) {
		triGenerator.init(sampligfreq);
	}

	/*!
	 * Resets the LFO to the beginning, when delay starts.
	 * Doesn't change the phase itself which starts where it was.
	 * It continues to live after the note is off
	 */
	void noteOn() {
		phase = 0;
	}

	void resetGeneratorPhase() {
		phase = 0;
		triGenerator.resetPhase();
	}

	/*!
	 * Sets the LFO ramp delay time
	 * 
	 * \param time Time in seconds
	 */
	void setDelay(double time) {
		delayPhase = time*triGenerator.getSamplingFreq();
		lfoRampSamples = LFORamp * triGenerator.getSamplingFreq();
		delayRampPhase = delayPhase - lfoRampSamples;
	}

	/*!
	 * Next sample at the given frequency
	 * 
	 * \param frequency Current LFO frequency (which can be modulated)
	 * \return A Value between -1.0 and 1.0
	 */
	double next(double frequency) {
		if (phase < delayRampPhase) {
			phase += 1.0;
			triGenerator.next(frequency);

			return 0;
		}
		 else if (phase < delayPhase) {
			double value = ((phase- delayRampPhase) / lfoRampSamples)*triGenerator.next(frequency);
			phase += 1.0;

			return value;
		}
		 else {
			phase += 1.0;
			return triGenerator.next(frequency);
		}
	}

	void skipDelay() {
		if (phase < delayPhase)
			phase = delayPhase;
	}

	/*!
	 * Move the generator phase of a given number of samples, with a frequency
	 * 
	 * \param freq The generator frequency
	 * \param samples The number of samples to go forward
	 */
	void move(double freq, double samples) {
		triGenerator.move(freq, samples);
	}

private:
	TriangleAliased triGenerator;
	double delayPhase = 0.0; // Delay in number of samples
	double delayRampPhase = 0.0;
	double phase = 0.0; // Current phase in sample count
	double lfoRampSamples = 0.0; 
};