base.hpp

#pragma once
#include "dsp/stereo_sample.h"
#include <cmath>
#include <span>
 
namespace deluge::dsp::reverb {
struct Base {
    Base() = default;
    virtual ~Base() = default;
 
    virtual void process(std::span<int32_t> input, std::span<StereoSample> output) = 0;
 
    constexpr void setPanLevels(const int32_t amplitude_left, const int32_t amplitude_right) {
        amplitude_right_ = amplitude_right;
        amplitude_left_ = amplitude_left;
    }
    enum class FilterType { LowPass, HighPass };
    template <FilterType filtertype>
    static constexpr float calcFilterCutoff(float f) {
        float minFreq;
        float maxFreq;
        // this exp will be between 1 and 4.48, half the knob range is about 2
        // for the HPF the result will then be from 0 to 500Hz with half the knob range at 300hz
        // then shift to 20-520Hz as there is a low end buildup in the reverb that should always be filtered out
        // for the LPF the result will be from 0 to 20000 with half the knob range at 5678.537hz
        if constexpr (filtertype == FilterType::LowPass) {
            minFreq = 0.0f;
            maxFreq = 5083.74f;
        }
        else if constexpr (filtertype == FilterType::HighPass) {
            minFreq = 20.0f;
            maxFreq = 150.0f;
        }
        float fc_hz = minFreq + (std::exp(1.5f * f) - 1) * maxFreq;
        float fc = fc_hz / float(kSampleRate);
        float wc = fc / (1 + fc);
        return wc;
    }
 
    // Dummy functions
    virtual void setRoomSize(float value) {}
    [[nodiscard]] virtual float getRoomSize() const { return 0; };
 
    virtual void setHPF(float f) {}
    [[nodiscard]] virtual float getHPF() const { return 0; }
 
    virtual void setLPF(float f) {}
    [[nodiscard]] virtual float getLPF() const { return 0; }
 
    virtual void setDamping(float value) {}
    [[nodiscard]] virtual float getDamping() const { return 0; }
 
    virtual void setWidth(float value) {}
    [[nodiscard]] virtual float getWidth() const { return 0; };
 
    [[nodiscard]] constexpr int32_t getPanLeft() const { return amplitude_left_; }
    [[nodiscard]] constexpr int32_t getPanRight() const { return amplitude_right_; }
 
private:
    int32_t amplitude_right_ = 0;
    int32_t amplitude_left_ = 0;
};
} // namespace deluge::dsp::reverb