zynaddsubfx

ZynAddSubFX open source synthesizer
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Portamento.h (4040B)

      1 /*
      2   ZynAddSubFX - a software synthesizer
      3 
      4   Portamento.h - Portamento calculation and management
      5   Copyright (C) 2021 Mark McCurry
      6   Author: Mark McCurry
      7 
      8   This program is free software; you can redistribute it and/or
      9   modify it under the terms of the GNU General Public License
     10   as published by the Free Software Foundation; either version 2
     11   of the License, or (at your option) any later version.
     12 */
     13 #ifndef PORTAMENTO_H
     14 #define PORTAMENTO_H
     15 #include "../globals.h"
     16 #include "../Params/Controller.h"
     17 #include <functional>
     18 
     19 namespace zyn {
     20 
     21 // Realtime struct governing portamento. Read by synth engines,
     22 // created and managed by parts.
     23 class Portamento {
     24     public:
     25         /**
     26          * Create a portamento.
     27          * Sets the active member if the portemento is activated.
     28          *
     29          * @param ctl The Controller which contains user patch parameters
     30          * @param synth The SYNTH_T from which to get sample rate and bufsize
     31          * @param is_running_note True if at least one note is playing
     32          * @param oldfreq_log2 Pitch of previous note
     33          * @param oldportamentofreq_log2 Starting pitch of the portamento
     34          * @param newfreq_log2 Ending pitch of the portamento
     35          */
     36         Portamento(const Controller &ctl,
     37                    const SYNTH_T &synth,
     38                    bool is_running_note,
     39                    float oldfreq_log2,
     40                    float oldportamentofreq_log2,
     41                    float newfreq_log2);
     42         /**
     43          * Initialize an already existing portamento.
     44          * Sets the active member if the portemento is activated.
     45          *
     46          * @param ctl The Controller which contains user patch parameters
     47          * @param synth The SYNTH_T from which to get sample rate and bufsize
     48          * @param is_running_note True if at least one note is playing
     49          * @param oldfreq_log2 Pitch of previous note
     50          * @param oldportamentofreq_log2 Starting pitch of the portamento
     51          * @param newfreq_log2 Ending pitch of the portamento
     52          */
     53         void init(const Controller &ctl,
     54                   const SYNTH_T &synth,
     55                   bool is_running_note,
     56                   float oldfreq_log2,
     57                   float oldportamentofreq_log2,
     58                   float newfreq_log2);
     59         /**Update portamento's freqrap to next value based upon dx*/
     60         void update(void);
     61         /**if the portamento is in use*/
     62         bool active;
     63         /**this value is used to compute the actual portamento
     64          *
     65          * This is the logarithmic power of two frequency
     66          * adjustment of the newer frequency to fit the profile of
     67          * the portamento.
     68          * This will be linear with respect to x.*/
     69         float freqdelta_log2;
     70 
     71     private:
     72         /**x is from 0.0f (start portamento) to 1.0f (finished portamento)*/
     73         float x;
     74         /**dx is the increment to x when update is called*/
     75         float dx;
     76         /** this is used for computing freqdelta_log2 value from x*/
     77         float origfreqdelta_log2;
     78 };
     79 
     80 class PortamentoRealtime {
     81     public:
     82         /**
     83          * Create a portamento realtime structure.
     84          *
     85          * @param handle handle to be used by cleanup function
     86          * @param memory Allocator used
     87          * @param cleanup Callback called from destructor
     88          * @param portamento Portamento object to be contained
     89          */
     90         PortamentoRealtime(void *handle,
     91                            Allocator &memory,
     92                            std::function<void(PortamentoRealtime *)> cleanup,
     93                            const Portamento &portamento);
     94 
     95         ~PortamentoRealtime();
     96 
     97         /**handle to be used by cleanup function in lieu of lambda capture*/
     98         void *handle;
     99         /**Allocator used to allocate memory*/
    100         Allocator &memory;
    101         /**Cleanup callback called by destructor*/
    102         std::function<void(PortamentoRealtime *)> cleanup;
    103         /**The actual portamento object*/
    104         Portamento portamento;
    105 };
    106 
    107 }
    108 
    109 #endif /* PORTAMENTO_H */