filter_set.h

/*
 * Copyright © 2015-2023 Synthstrom Audible Limited
 *
 * This file is part of The Synthstrom Audible Deluge Firmware.
 *
 * The Synthstrom Audible Deluge Firmware is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program.
 * If not, see <https://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "definitions_cxx.hpp"
#include "dsp/filter/hpladder.h"
#include "dsp/filter/lpladder.h"
#include "dsp/filter/svf.h"
#include "model/mod_controllable/filters/filter_config.h"
#include "util/fixedpoint.h"
#include <cstdint>
 
class Sound;
 
namespace deluge::dsp::filter {
 
union LowPass {
    LpLadderFilter ladder;
    SVFilter svf;
    LowPass() {}
};
 
union HighPass {
    HpLadderFilter ladder;
    SVFilter svf;
    HighPass() {}
};
 
class FilterSet {
public:
    void reset();
    int32_t setConfig(q31_t lpfFrequency, q31_t lpfResonance, FilterMode lpfmode, q31_t lpfMorph, q31_t hpfFrequency,
                      q31_t hpfResonance, FilterMode hpfmode, q31_t hpfMorph, q31_t filterGain, FilterRoute routing,
                      bool adjustVolumeForHPFResonance, q31_t* overallOscAmplitude);
 
    void renderLong(std::span<q31_t> buffer);
 
    // expects to receive an interleaved stereo stream
    void renderLongStereo(std::span<StereoSample> buffer);
 
    // used to check whether the filter is used at all
    bool isLPFOn() { return LPFOn; }
    bool isHPFOn() { return HPFOn; }
    bool isOn() { return HPFOn || LPFOn; }
 
private:
    FilterMode lpfMode_;
    FilterMode lastLPFMode_;
    FilterMode hpfMode_;
    FilterMode lastHPFMode_;
    FilterRoute routing_;
 
    void renderLPFLong(std::span<q31_t> buffer);
    void renderLPFLongStereo(std::span<StereoSample> buffer);
    void renderHPFLongStereo(std::span<StereoSample> buffer);
    void renderHPFLong(std::span<q31_t> buffer);
 
    // all filters share a state. This is fine since they just hold plain data and initialization is handled by
    // reset/configure calls.  This is faster than using a variant at the cost of not throwing on incorrect access.
    // However since there are no invariants to uphold, the worst case scenario is an audio glitch so whatever
    // This cuts 250 bytes from the size of this class, which is fairly significant since every voice has a filterset
    LowPass lpfilter;
    HighPass hpfilter;
 
    bool LPFOn;
    bool HPFOn;
};
} // namespace deluge::dsp::filter