serumalt/Source/SynthVoice.cpp

#include "SynthVoice.h"

namespace serum
{

namespace
{
    inline float clampF (float v, float lo, float hi) noexcept
    {
        return v < lo ? lo : (v > hi ? hi : v);
    }
}

void SynthVoice::prepare (double sampleRate, int maxBlockSize)
{
    oscA.prepare (sampleRate);
    oscB.prepare (sampleRate);
    sub.prepare (sampleRate);
    noise.prepare (sampleRate);
    filters.prepare (sampleRate, maxBlockSize);
    for (auto& e : env)
        e.prepare (sampleRate);
    scratch.setSize (2, maxBlockSize, false, false, true);
    reset();
}

void SynthVoice::reset()
{
    oscA.reset(); oscB.reset();
    sub.reset(); noise.reset();
    filters.reset();
    for (auto& e : env)
        e.reset();
    note = -1;
    velocity = 0.0f;
    baseFreq = 0.0;
    active = released = false;
    noteId = 0;
    oscillatorsNeedNoteOn = false;
    noteRandom = 0.5f;
    scratch.clear();
}

void SynthVoice::noteOn (int noteNumber, float velocity01, double freqHz, juce::uint32 noteSeed)
{
    note      = noteNumber;
    velocity  = velocity01;
    baseFreq  = freqHz;
    active    = true;
    released  = false;
    seed      = noteSeed;
    noteId    = noteSeed;
    oscillatorsNeedNoteOn = true;   // initialise fresh oscillator phases on first render

    juce::Random rng (noteSeed);
    noteRandom = rng.nextFloat();

    sub.noteOn (freqHz, -1);
    noise.noteOn (noteSeed);

    for (auto& e : env)
        e.noteOn();
}

void SynthVoice::noteOff()
{
    if (! active || released)
        return;
    released = true;
    for (auto& e : env)
        e.noteOff();
}

void SynthVoice::render (float* outL, float* outR, int numSamples, const RenderContext& ctx) noexcept
{
    if (! active || numSamples <= 0)
        return;

    // 1. Refresh envelope parameters (cheap; also lets UI edits affect held notes).
    for (int i = 0; i < kNumEnvelopes; ++i)
        env[(size_t) i].setParams (maps::toSeconds (ctx.envAttack[i]),
                                   maps::toSeconds (ctx.envDecay[i]),
                                   ctx.envSustain[i],
                                   maps::toSeconds (ctx.envRelease[i]),
                                   ctx.envCurve[i]);

    // 2. Block-start envelope values (control-rate modulation sources).
    float envStart[kNumEnvelopes];
    for (int i = 0; i < kNumEnvelopes; ++i)
        envStart[i] = env[(size_t) i].getValue();

    // 3. Per-voice modulation source values.
    float src[kNumModSources];
    src[(int) ModSource::Lfo1] = ctx.lfoValues[0];
    src[(int) ModSource::Lfo2] = ctx.lfoValues[1];
    src[(int) ModSource::Lfo3] = ctx.lfoValues[2];
    src[(int) ModSource::Lfo4] = ctx.lfoValues[3];
    src[(int) ModSource::Env1] = envStart[0];
    src[(int) ModSource::Env2] = envStart[1];
    src[(int) ModSource::Env3] = envStart[2];
    src[(int) ModSource::Env4] = envStart[3];
    src[(int) ModSource::Velocity] = velocity;
    src[(int) ModSource::Note]     = clampF ((float) note / 127.0f, 0.0f, 1.0f);
    src[(int) ModSource::ModWheel] = ctx.modWheel;
    src[(int) ModSource::PitchBend]= ctx.pitchBend;
    src[(int) ModSource::Macro1] = ctx.macroValues[0];
    src[(int) ModSource::Macro2] = ctx.macroValues[1];
    src[(int) ModSource::Macro3] = ctx.macroValues[2];
    src[(int) ModSource::Macro4] = ctx.macroValues[3];
    src[(int) ModSource::Random] = noteRandom;

    // 4. Accumulate modulation offsets (block rate).
    std::array<float, kNumModTargets> mod { { } };
    if (ctx.matrix != nullptr)
    {
        for (const auto& c : ctx.matrix->connections)
        {
            float v = src[(int) c.source];
            if (c.bipolar && ! isBipolarSource (c.source))
                v = v * 2.0f - 1.0f;
            mod[(int) c.target] += v * c.depth;
        }
    }
    if (ctx.macros != nullptr)
    {
        for (int m = 0; m < kNumMacros; ++m)
            for (const auto& a : ctx.macros->assignments[(size_t) m])
                mod[(int) a.target] += ctx.macroValues[m] * a.depth;
    }

    // 5. Modulated oscillator parameters.
    OscParams a = ctx.oscA;
    OscParams b = ctx.oscB;
    a.level    = clampF (a.level  + mod[(int) ModTarget::OscALevel], 0.0f, 1.0f);
    a.pan      = clampF (a.pan    + mod[(int) ModTarget::OscAPan], -1.0f, 1.0f);
    a.wtPos    = clampF (a.wtPos  + mod[(int) ModTarget::OscAWtPos], 0.0f, 1.0f);
    a.unison   = (int) std::llround (clampF ((float) a.unison + mod[(int) ModTarget::OscAUnison] * 16.0f, 1.0f, 16.0f));
    a.detune   = clampF (a.detune + mod[(int) ModTarget::OscADetune], 0.0f, 1.0f);
    a.spread   = clampF (a.spread + mod[(int) ModTarget::OscASpread], 0.0f, 1.0f);
    a.warpAmt  = clampF (a.warpAmt+ mod[(int) ModTarget::OscAWarpAmt], 0.0f, 1.0f);

    b.level    = clampF (b.level  + mod[(int) ModTarget::OscBLevel], 0.0f, 1.0f);
    b.pan      = clampF (b.pan    + mod[(int) ModTarget::OscBPan], -1.0f, 1.0f);
    b.wtPos    = clampF (b.wtPos  + mod[(int) ModTarget::OscBWtPos], 0.0f, 1.0f);
    b.unison   = (int) std::llround (clampF ((float) b.unison + mod[(int) ModTarget::OscBUnison] * 16.0f, 1.0f, 16.0f));
    b.detune   = clampF (b.detune + mod[(int) ModTarget::OscBDetune], 0.0f, 1.0f);
    b.spread   = clampF (b.spread + mod[(int) ModTarget::OscBSpread], 0.0f, 1.0f);
    b.warpAmt  = clampF (b.warpAmt+ mod[(int) ModTarget::OscBWarpAmt], 0.0f, 1.0f);

    // 6. Frequency (pitch bend + mod matrix pitch + per-osc coarse/fine).
    const double semis = ctx.pitchBend * ctx.pitchBendRange + mod[(int) ModTarget::Pitch] * 24.0;
    const double bent  = baseFreq * std::pow (2.0, semis / 12.0);
    const double freqA = bent * std::pow (2.0, (double) a.coarse / 12.0 + (double) a.fine / 1200.0);
    const double freqB = bent * std::pow (2.0, (double) b.coarse / 12.0 + (double) b.fine / 1200.0);

    // Initialise phases only for a fresh note; update held-note unison parameters
    // without resetting existing phases when modulated at control rate.
    if (oscillatorsNeedNoteOn)
    {
        oscA.noteOn (freqA, a, seed);
        oscB.noteOn (freqB, b, seed + 1);
        oscillatorsNeedNoteOn = false;
    }
    else
    {
        oscA.setParams (a);
        oscB.setParams (b);
    }

    // 7. Modulated filter parameters.
    FilterBankParams fb = ctx.filters;
    fb.f1Cutoff = clampF (fb.f1Cutoff + mod[(int) ModTarget::Filter1Cutoff], 0.0f, 1.0f);
    fb.f1Res    = clampF (fb.f1Res    + mod[(int) ModTarget::Filter1Res], 0.0f, 1.0f);
    fb.f1Drive  = clampF (fb.f1Drive  + mod[(int) ModTarget::Filter1Drive], 0.0f, 1.0f);
    fb.f2Cutoff = clampF (fb.f2Cutoff + mod[(int) ModTarget::Filter2Cutoff], 0.0f, 1.0f);
    fb.f2Res    = clampF (fb.f2Res    + mod[(int) ModTarget::Filter2Res], 0.0f, 1.0f);
    fb.f2Drive  = clampF (fb.f2Drive  + mod[(int) ModTarget::Filter2Drive], 0.0f, 1.0f);
    fb.mix      = clampF (fb.mix      + mod[(int) ModTarget::FilterMix], 0.0f, 1.0f);
    fb.out      = clampF (fb.out      + mod[(int) ModTarget::FilterOut], 0.0f, 1.5f);

    // 8. Amp modulation + velocity.
    const float ampMod  = 1.0f + mod[(int) ModTarget::Amp];
    const float velGain = velocity * velocity + 0.001f;

    // 9. Generate oscillators/sub/noise into scratch.
    float* sL = scratch.getWritePointer (0);
    float* sR = scratch.getWritePointer (1);
    const Wavetable& wtA = ctx.wavetables->getTable (a.wave);
    const Wavetable& wtB = ctx.wavetables->getTable (b.wave);
    const double subMult = (ctx.subOct == -2) ? 0.25 : (ctx.subOct == -1) ? 0.5 : 1.0;
    const float subLevel = clampF (ctx.subLevel + mod[(int) ModTarget::SubLevel], 0.0f, 1.0f);
    const float noiseLevel = clampF (ctx.noiseLevel + mod[(int) ModTarget::NoiseLevel], 0.0f, 1.0f);

    for (int i = 0; i < numSamples; ++i)
    {
        float l = 0.0f, r = 0.0f;
        oscA.processAdd (wtA, a, freqA, l, r);
        oscB.processAdd (wtB, b, freqB, l, r);

        float mono = 0.0f;
        if (ctx.subOn)
            sub.processAdd (bent * subMult, ctx.subShape, subLevel, mono);
        if (ctx.noiseOn)
            noise.processAdd (ctx.noiseType, noiseLevel, mono);
        l += mono;
        r += mono;

        sL[i] = l;
        sR[i] = r;
    }

    // 10. Filter bank (control rate).
    filters.process (sL, sR, numSamples, fb, (float) baseFreq);

    // 11. Amp envelope (per sample) and advance the remaining envelopes.
    for (int i = 0; i < numSamples; ++i)
    {
        const float amp = env[0].process();
        env[1].process();
        env[2].process();
        env[3].process();

        const float gain = amp * ampMod * velGain;
        outL[i] += sL[i] * gain;
        outR[i] += sR[i] * gain;
    }

    // 12. Release completes when the amp envelope has fully decayed.
    if (released && ! env[0].isActive())
        active = false;
}

} // namespace serum