DaisySP_TeensyDaisySP_Teensy/DaisySP/PhysicalModeling/stringvoice.cpp

#include "stringvoice.h"
#include <algorithm>
#include "../utility/dsp.h"

using namespace daisysp;

void StringVoice::Init(float sample_rate)
{
    sample_rate_ = sample_rate;

    excitation_filter_.Init(sample_rate);
    string_.Init(sample_rate_);
    dust_.Init();
    remaining_noise_samples_ = 0;

    SetSustain(false);
    SetFreq(440.f);
    SetAccent(.8f);
    SetStructure(.7f);
    SetBrightness(.2f);
    SetDamping(.7f);
}

void StringVoice::Reset()
{
    string_.Reset();
}

void StringVoice::SetSustain(bool sustain)
{
    sustain_ = sustain;
}

void StringVoice::Trig()
{
    trig_ = true;
}

void StringVoice::SetFreq(float freq)
{
    string_.SetFreq(freq);
    f0_ = freq / sample_rate_;
    f0_ = fclamp(f0_, 0.f, .25f);
}

void StringVoice::SetAccent(float accent)
{
    accent_ = fclamp(accent, 0.f, 1.f);
}

void StringVoice::SetStructure(float structure)
{
    structure = fclamp(structure, 0.f, 1.f);
    const float non_linearity
        = structure < 0.24f
              ? (structure - 0.24f) * 4.166f
              : (structure > 0.26f ? (structure - 0.26f) * 1.35135f : 0.0f);
    string_.SetNonLinearity(non_linearity);
}

void StringVoice::SetBrightness(float brightness)
{
    brightness_ = fclamp(brightness, 0.f, 1.f);
    density_    = brightness_ * brightness_;
}

void StringVoice::SetDamping(float damping)
{
    damping_ = fclamp(damping, 0.f, 1.f);
}

float StringVoice::GetAux()
{
    return aux_;
}

float StringVoice::Process(bool trigger)
{
    const float brightness = brightness_ + .25 * accent_ * (1.f - brightness_);
    const float damping    = damping_ + .25 * accent_ * (1.f - damping_);

    // Synthesize excitation signal.
    if(trigger || trig_ || sustain_)
    {
        trig_              = false;
        const float range  = 72.0f;
        const float f      = 4.0f * f0_;
        const float cutoff = fmin(
            f
                * powf(2.f,
                       kOneTwelfth * (brightness * (2.0f - brightness) - 0.5f)
                           * range),
            0.499f);
        const float q            = sustain_ ? 1.0f : 0.5f;
        remaining_noise_samples_ = static_cast<size_t>(1.0f / f0_);
        excitation_filter_.SetFreq(cutoff * sample_rate_);
        excitation_filter_.SetRes(q);
    }

    float temp = 0.f;

    if(sustain_)
    {
        const float dust_f = 0.00005f + 0.99995f * density_ * density_;
        dust_.SetDensity(dust_f);
        temp = dust_.Process() * (8.0f - dust_f * 6.0f) * accent_;
    }
    else if(remaining_noise_samples_)
    {
        temp = 2.0f * rand() * kRandFrac - 1.0f;
        remaining_noise_samples_--;
        remaining_noise_samples_ = DSY_MAX(remaining_noise_samples_, 0.f);
    }

    excitation_filter_.Process(temp);
    temp = excitation_filter_.Low();

    aux_ = temp;

    string_.SetBrightness(brightness);
    string_.SetDamping(damping);

    return string_.Process(temp);
}