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/*
* Copyright (C) 2021 Linux Studio Plugins Project <https://lsp-plug.in/>
* (C) 2021 Stefano Tronci <stefano.tronci@protonmail.com>
*
* This file is part of lsp-dsp-units
* Created on: 13 Jun 2021
*
* lsp-plugins is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* lsp-plugins 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with lsp-plugins. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef LSP_PLUG_IN_DSP_UNITS_NOISE_LCG_H_
#define LSP_PLUG_IN_DSP_UNITS_NOISE_LCG_H_
#include <lsp-plug.in/dsp-units/util/Randomizer.h>
#include <lsp-plug.in/dsp-units/iface/IStateDumper.h>
namespace lsp
{
namespace dspu
{
enum lcg_dist_t
{
LCG_UNIFORM, // Uniform over [-1, 1), X fAmplitude + fOffset
LCG_EXPONENTIAL, // Double sided exponential over [-1, 1], X fAmplitude + fOffset
LCG_TRIANGULAR, // Triangular over [-1, 1], X fAmplitude + fOffset
LCG_GAUSSIAN, // Gaussian of mean 0 and standard deviation 1, X fAmplitude + fOffset
LCG_MAX
};
/** LCG stands for Linear Congruential Generator.
* LCG generate pseudorandom sequences by using a recurrence relation.
* This relation is defined in the Randomizer class.
* This class builds upon Randomizer by providing support for common distributions.
* Output noise is easily scalable, and offset is also supported.
*
*/
class LSP_DSP_UNITS_PUBLIC LCG
{
private:
LCG & operator = (const LCG &);
LCG(const LCG &);
private:
lcg_dist_t enDistribution;
float fAmplitude;
float fOffset;
Randomizer sRand;
public:
explicit LCG();
~LCG();
void construct();
void destroy();
public:
/** Initialize random generator
*
* @param seed seed
*/
void init(uint32_t seed);
/** Initialize random generator, take current time as seed
*/
void init();
/** Set the distribution for the noise.
*
* @param dist distribution for the noise sequence.
*/
inline void set_distribution(lcg_dist_t dist)
{
if ((dist < LCG_UNIFORM) || (dist >= LCG_MAX))
return;
enDistribution = dist;
}
/** Set the amplitude of the LCG sequence.
*
* @param amplitude amplitude value for the sequence.
*/
inline void set_amplitude(float amplitude)
{
if (amplitude == fAmplitude)
return;
fAmplitude = amplitude;
}
/** Set the offset of the LCG sequence.
*
* @param offset offset value for the sequence.
*/
inline void set_offset(float offset)
{
if (offset == fOffset)
return;
fOffset = offset;
}
/** Get a sample from the LCG generator.
*
* @return the next sample in the LCG sequence.
*/
float process_single();
/** Output sequence to the destination buffer in additive mode
*
* @param dst output wave destination
* @param src input source, allowed to be NULL
* @param count number of samples to synthesise
*/
void process_add(float *dst, const float *src, size_t count);
/** Output sequence to the destination buffer in multiplicative mode
*
* @param dst output wave destination
* @param src input source, allowed to be NULL
* @param count number of samples to process
*/
void process_mul(float *dst, const float *src, size_t count);
/** Output sequence to a destination buffer overwriting its content
*
* @param dst output wave destination
* @param src input source, allowed to be NULLL
* @param count number of samples to process
*/
void process_overwrite(float *dst, size_t count);
/**
* Dump the state
* @param dumper dumper
*/
void dump(IStateDumper *v) const;
};
}
}
#endif /* LSP_PLUG_IN_DSP_UNITS_NOISE_LCG_H_ */
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