rmx-19/Source/SynthEngine.h

#pragma once
#include <juce_audio_processors/juce_audio_processors.h>
#include "Params.h"

struct VParams
{
    float osc1w = 2, osc2w = 3, detune = 8, oscMix = 52.f;
    float fltType = 1, fltCut = 3400.f, fltRes = 0.18f, fltEnv = 52.f, fltKey = 40.f;
    float ampA = 0.008f, ampD = 0.26f, ampS = 0.70f, ampR = 0.35f;
    float fA = 0.02f, fD = 0.16f, fS = 0.26f, fR = 0.25f;
    float lfoRate = 4.2f, lfoShape = 0, lfoDepth = 0.22f, lfoTarget = 0;
    float fxType = 1, fxAmt = 0.30f, fxTime = 0.28f;
    float vol = 0.85f, pan = 0.0f, poly = 10.f, glide = 0.f, tune = 0.f;
    float hq = 0.0f;
    float arpOn = 0, arpRate = 2, arpPattern = 0, arpOct = 1, arpGate = 70;

    void update (const juce::AudioProcessorValueTreeState& apvts)
    {
        auto get = [&] (const char* id) { return apvts.getRawParameterValue (id) -> load(); };
        osc1w    = get ("osc1wave"); osc2w = get ("osc2wave"); detune = get ("detune");
        oscMix   = get ("oscmix");
        fltType  = get ("flttype");  fltCut = get ("fltcut"); fltRes = get ("fltres");
        fltEnv   = get ("fltenv");   fltKey = get ("fltkey");
        ampA     = get ("ampA");     ampD = get ("ampD");     ampS = get ("ampS");
        ampR     = get ("ampR");
        fA       = get ("fenvA");    fD = get ("fenvD");      fS = get ("fenvS");
        fR       = get ("fenvR");
        lfoRate  = get ("lforate");  lfoShape = get ("lfoshape"); lfoDepth = get ("lfodepth");
        lfoTarget= get ("lfotarget");
        fxType   = get ("fxtype");   fxAmt = get ("fxamt");   fxTime = get ("fxtime");
        vol      = get ("vol");      pan = get ("pan");       poly = get ("poly");
        glide    = get ("glide");    tune = get ("tune");
        hq       = get ("hq");
        arpOn    = get ("arpon");
        arpRate  = get ("arprate");
        arpPattern = get ("arppattern");
        arpOct   = get ("arpoct");
        arpGate  = get ("arpgate");
    }
};

// ---------------------------------------------------------------------------

class Env
{
public:
    enum State { Off, Atk, Dec, Sus, Rel };

    void setRates (float a, float d, float s, float r, double sr)
    {
        srInv = 1.0 / sr;
        attTau = 1.0f / (0.001f + 0.25f * a);
        decTau = 1.0f / (0.001f + 0.35f * d);
        relTau = 1.0f / (0.001f + 0.30f * r);
        susL = s;
    }

    void noteOn () { st = Atk; }

    void noteOff ()
    {
        if (st != Off && st != Rel) st = Rel;
    }

    void reset (float v = 0.0f) { cur = v; st = Off; }

    float next()
    {
        switch (st)
        {
            case Atk:
                cur += (1.0f - cur) * std::min (1.0f, (float) (attTau * srInv) * 8.0f);
                if (cur >= 1.0f) { cur = 1.0f; st = Dec; }
                break;
            case Dec:
                cur = susL + (cur - susL) * std::exp (-decTau * (float) srInv);
                if (std::abs (cur - susL) < 0.001f) { cur = susL; st = Sus; }
                break;
            case Sus: break;
            case Rel:
                cur *= std::exp (-relTau * (float) srInv);
                if (cur < 0.0002f) { cur = 0.0f; st = Off; }
                break;
            case Off: break;
        }
        return cur;
    }

    bool running() const     { return st != Off; }
    float getCur() const     { return cur; }
    State getState() const   { return st; }

private:
    float cur = 0.0f, susL = 0.7f;
    float attTau = 1.0f, decTau = 1.0f, relTau = 1.0f;
    double srInv = 1.0 / 48000.0;
    State st = Off;
};

// ---------------------------------------------------------------------------

class SynthEngine
{
public:
    SynthEngine();
    ~SynthEngine();

    void setSampleRate (double sr);
    void noteOn  (int midiNote, float velocity);
    void noteOff (int midiNote);
    void allNotesOff (bool immediate);
    void sustainPedal (bool down);
    void pitchBend (float cents);
    void modWheel (float v);

    void render (const VParams& p, float* left, float* right, int numSamples);

    int  activeVoices() const noexcept  { return active; }

private:
    struct Voice
    {
        bool  active = false;
        int   note = 0;
        float vel = 1.0f;
        float panL = 0.71f, panR = 0.71f;
        float curFreq = 0.0f, targetFreq = 0.0f;
        double ph1 = 0.0, ph2 = 0.0, lfoPh = 0.0;
        float lfoSH = 0.0f;
        int   lfoIdx = 0;
        Env amp, flt;
        float lp = 0.0f, bp = 0.0f, f1c = 0.0f;
        float fcSm = 0.0f;
        float outSmooth = 0.0f;
    };

    static constexpr int maxVoice = 16;
    Voice voices[maxVoice];
    double sr = 48000.0;
    int active = 0;
    int polyLimit = 16;
    float mod = 0.0f, bendCents = 0.0f, bendSmooth = 0.0f;
    bool pedal = false;
    float lastNoteFreq = 440.0f, lastGlide = 0.0f, lastPan = 0.0f;
    int stealIdx = 0;
    juce::Random rng;
    juce::Array<int> sustainedNotes;

    float osc (int wave, double ph);
    Voice* acquireVoice();
};